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669f5ed073 ... v0.12.0

Author SHA1 Message Date
ddidderr 227f78a767 [release] fcry v0.12.0 2026-06-10 20:49:21 +02:00
ddidderr 1ea1e65deb license: change from GPL-3.0 to MIT-0 2026-06-10 20:49:12 +02:00
ddidderr 90707cc364 updated README 2026-06-10 01:41:41 +02:00
ddidderr 6febf8ee22 fmt: tombi format 2026-06-10 01:24:38 +02:00
ddidderr d79e96c498 [release] fcry v0.11.0 2026-06-10 01:22:42 +02:00
ddidderr 99705afa9e deps: cargo update 2026-06-10 01:21:42 +02:00
ddidderr 3f53c221c8 test: tolerate closed stdin in chunk-size failure 
The chunk-size-zero regression test spawned fcry with stdin piped and
unconditionally unwrapped the write into that pipe. That made the test depend
on scheduler timing: the child may validate --chunk-size 0, report the error,
and exit before it has drained stdin.

Treat BrokenPipe as the expected early-exit shape for this failing command,
while still failing on any other write error and still asserting that the
process exits unsuccessfully. The valid empty-stdin chunk-size case remains
unchanged.

Test Plan:
- cargo fmt --check
- cargo test
- cargo clippy --all-targets -- -D warnings
- git diff --check

Refs: none
 2026-06-10 00:20:10 +02:00
ddidderr 725d33939e fix: read key files through short reads 
Read --key-file input in a loop until EOF or until the 33-byte rejection
threshold is reached. A single read call is enough for ordinary regular files
in practice, but FIFOs and process substitution can legally return fewer than
32 bytes before EOF. Treating that first short read as final made the new
key-file path fail spuriously for exactly the shell-friendly usage it was meant
to support.

Keep the existing exact-length policy: 32 bytes is accepted, shorter files are
rejected, and 33 or more bytes are rejected with the trailing-newline hint.
The intermediate buffer remains zeroizing.

Test Plan:
- cargo test split_fifo_key_file_read_roundtrips
- cargo fmt --check
- cargo clippy --all-targets -- -D warnings
- cargo test
- git diff --check

Refs: review finding for --key-file short reads
 2026-06-09 23:46:27 +02:00
ddidderr 81ac1475ad feat: harden fcry format and IO policy 
Introduce a central policy module for format and resource validation, then
route header parsing, KDF acceptance, range arithmetic, and pipeline sizing
through that policy. New encryptions now write v3 headers that include an
authenticated key commitment, which lets decrypt reject wrong keys or
passphrases before chunk processing while preserving valid v1/v2 decrypt
compatibility inside the configured caps.

Replace process-list-visible raw key input with --key-file, add passphrase NFC
normalization, enforce stronger new-encryption passphrase/KDF floors unless
--allow-weak-kdf is supplied, and add a configurable decrypt Argon2 memory
ceiling. Chunk buffers in the serial, parallel, and lookahead paths now use
zeroizing storage.

Rework output handling around randomized create-new temporary files with Unix
0600 mode, file fsync before persist, best-effort parent directory fsync,
default no-overwrite behavior, safe in-place replacement, --force, --temp-dir,
and --buffer-verify for decrypt-to-stdout.

Known caveat: --key-file currently reads with a single read call. That is fine
for regular files but can reject short reads from pipes or process
substitution. A follow-up fix will make key-file reads loop before EOF.

Test Plan:
- cargo fmt --check
- cargo clippy --all-targets -- -D warnings
- cargo test
- git diff --check
- cargo run -- --help

Refs: fcry security hardening plan
 2026-06-09 23:45:02 +02:00
ddidderr d7b0127d20 review: Claude Fable 5 2026-06-09 22:06:30 +02:00
ddidderr 67b412a1a5 fmt: tombi 2026-05-30 18:57:06 +02:00
ddidderr 6898297973 deps: cargo update 2026-05-16 17:26:15 +02:00
ddidderr 45571c98fe Cargo.toml: remove authors, format with tombi 2026-05-16 17:25:57 +02:00
ddidderr acd2712ade sec review 2026-05-03 14:48:55 +02:00
ddidderr ea2e43fe3d Revert "feat(cli): default to interactive passphrase when no key source given" 
This reverts commit f72f9034f3.
 2026-05-02 21:30:58 +02:00
ddidderr 2c101abdbd fix(cli): reject -j 0 instead of silently falling through to serial 
`--threads` was an `Option<usize>` with no value-parser bound. Passing
`-j 0` slipped past clap and reached the dispatch in `crypto::encrypt`
/ `decrypt`, where the `threads > 1` check evaluates to false for 0 and
the call quietly fell through to the serial path. The user thought
they had asked for "no worker threads" and got something else instead;
either way, 0 workers is not a meaningful configuration.

Switch the field to `Option<u32>` and add `value_parser!(u32).range(1..)`
so clap rejects `-j 0` at parse time with a usage error. Cast to
`usize` at the single use site. Using `u32` rather than `usize` avoids
shipping a host-pointer-width-dependent CLI surface; thread counts well
past 4 billion are not a thing we need to plan for.

Test plan:
  - New integration test `rejects_zero_threads` invokes the binary
    with `-j 0` and asserts non-zero exit.
  - Existing `roundtrip_multi_threaded` (`-j 4`) still passes, so the
    range bound has not broken normal usage.

Refs: external review (GLM51 #1; Gemini #3 misdescribed the symptom
as "silent corruption" — verified the actual behaviour was a fall-
through to the serial path, not output corruption, but the fix is
the same).
 2026-05-02 21:29:28 +02:00
ddidderr 91b459657e fix(pipeline): bound reorder buffer and fail fast on worker error 
The multi-threaded pipeline introduced in 75afadb had two related defects
flagged by external review:

1. The writer's reorder buffer was unbounded. `ordered_writer` accepted
   a `_cap` parameter that was documented as the in-flight bound but
   was never read. The writer drained `done_rx` eagerly into a
   `BTreeMap`, so neither the bounded job channel nor the bounded done
   channel ever exerted backpressure on the reader. A slow or stuck
   worker would let the writer accumulate every subsequent chunk in
   `pending` until the system ran out of memory. With adversarial input
   this is a memory-exhaustion vector; with merely uneven workers it
   silently violated the documented memory ceiling.

2. The pipeline did not fail fast. When a worker hit an AEAD
   authentication failure it returned `Err`, dropped its channel
   clones, and exited — but the other workers, the reader, and the
   writer kept running until natural EOF. On a tampered N-byte file
   we burned full I/O plus (T-1)/T of the AEAD CPU before surfacing
   the error. Combined with (1) this also stretched the window in
   which `pending` could grow.

Both issues are addressed by a single rewrite of `pipeline.rs`:

  - A bounded "permit" channel pre-filled with `in_flight_capacity`
    `()` tokens. The reader acquires one before sending each job; the
    writer releases one after flushing the corresponding chunk in
    order. Total in-flight chunks (queued jobs + in-progress at
    workers + pending in the reorder map) is now hard-capped at
    `4 * threads`, with the writer in lockstep with the actual disk
    write rather than ahead of it.

  - An `Arc<AtomicBool> cancel` flag that workers set on AEAD failure.
    Workers check it at the top of their loop and drain remaining
    queued jobs without doing AEAD work. The reader checks it before
    each new chunk, so a tampered chunk causes the reader to stop
    within the in-flight window rather than after EOF.

The reader uses `permit_rx.recv_timeout(50ms)` rather than a blocking
`recv` so it can poll the cancel flag even when the rest of the
pipeline has quiesced. Without this, a 3-way deadlock is possible:
worker errors after all permits are out, the writer is blocked on a
missing-counter chunk that will never arrive, the other workers are
idle on `jobs_rx`, and the reader is blocked on `permit_rx`. The
50 ms wakeup is well below typical user-perceptible latency and only
runs when the pipeline is otherwise idle, so its cost is negligible.

While rewriting I also collapsed `encrypt_parallel`/`decrypt_parallel`
onto a shared `run_pipeline` helper parameterised by an `is_encrypt`
bool — the two functions previously duplicated ~150 lines of channel
plumbing for a one-line difference (`encrypt_in_place` vs
`decrypt_in_place`). Same for the reorder writer: a single
`ordered_writer` now returns `(OutSink, u64)`, and encrypt simply
ignores the byte count (decrypt uses it for the length cross-check).
Removed the stale "wrapping_add" on the in-order counter — wrapping
here would mask a real bug since `bump_counter` already rejects
overflow upstream — and corrected the per-thread memory estimate in
the module-level doc to match the new bounded model.

The job-channel capacity (`channel_capacity = 2 * threads`) is left
unchanged. The new permit cap (`4 * threads`) is deliberately larger
so out-of-order completion has slack; if the gap is ever exhausted
the only consequence is reader backpressure, never unbounded growth.

Test plan:
  - `cargo test` still passes the full 28-test integration suite,
    including `parallel_and_serial_outputs_round_trip` (proves the
    refactored unified pipeline produces bit-identical output to the
    serial path) and `rejects_tampered_ciphertext` (still surfaces
    the AEAD error, now via the cancel path).
  - Manual fail-fast probe: 200 MiB random plaintext, encrypt with
    `-j 8`, flip a byte at offset 2000 (inside chunk 0), decrypt
    with `-j 8`. Errors in ~2 ms, vs ~28 ms for a clean decrypt of
    the same file — confirming the reader stopped within the
    in-flight window rather than draining the whole input.
  - The `ordered_writer` cancel deadlock case is hit organically by
    the same probe: chunk 0 fails authentication, no further
    counter-0 chunk ever arrives, but the reader exits via the
    50 ms cancel poll and the rest of the pipeline drains.

Refs: external review (P2 / Gemini #1, Gemini #2, GLM51 #2/#7/#8).
 2026-05-02 21:29:08 +02:00
ddidderr 53bb927a87 fix(header): preserve on-disk version through decode/encode 
`Header::encode()` previously hard-coded `VERSION_CURRENT` (= 2) on every
write. Because the encoded header is fed back as AEAD AAD on decrypt, this
broke decryption of any v1 ciphertext written before commit 75afadb: the
file's authenticated AAD has version byte 1, but the recomputed AAD has
byte 2, so AEAD verification fails on every chunk. The release notes for
75afadb explicitly promised v1 compatibility, so this is a regression
against the documented contract — caught by an external reviewer who
reproduced it by encrypting with HEAD^ and decrypting with HEAD.

Fix by adding a `version: u8` field to `Header`. `Header::read()` now
captures the on-disk byte and `encode()` writes it back. New encrypts in
`crypto::encrypt()` set `version = VERSION_CURRENT`, so freshly written
files are unchanged on the wire; only the round-trip path through
`read → encode` is now byte-identical for v1 inputs.

This was the simplest fix that preserves the existing AAD design (header
bytes verbatim → AAD). Alternatives considered:

  - Storing the raw header bytes alongside the parsed struct would also
    work but spends an extra allocation and adds a second source of
    truth for the same data.
  - Conditionally emitting v2 only when flags != 0 would happen to
    produce v1 bytes for a v1 input, but it conflates "what version
    does this file claim" with "does it carry length commitment" — two
    things that should stay independent for future flag bits.

Test plan:
  - `header::tests::reads_v1_header` now also asserts that re-encoding
    a parsed v1 header reproduces the original bytes exactly (so the
    AAD round-trips).
  - New `crypto::tests::decrypts_v1_ciphertext` and
    `decrypts_v1_ciphertext_parallel` build a multi-chunk v1 fixture
    by hand (XChaCha20Poly1305 with version-byte-1 AAD) and confirm
    `decrypt()` succeeds on both the serial and parallel paths.
  - Manual: built `HEAD^` in a worktree, encrypted a 200-byte payload
    with `--chunk-size 64`, decrypted with the patched binary at
    `-j 1` and `-j 4`. Both round-trip; output bytes match input.

Refs: external review identifying this regression.
 2026-05-02 21:28:26 +02:00
ddidderr 75afadb1ec feat!: multi-threaded pipeline + length-committed/random-access decrypt 
Completes the two follow-ups deferred from the v0.10 format/secrets
work: multi-threaded AEAD encrypt/decrypt and a length-committed file
format that enables random-access decryption.

# Format change (file format v2)

Bumps the on-disk header version to 2 and introduces a flag bit
(`FLAG_LENGTH_COMMITTED`, bit 0). When set, an authenticated `u64 LE`
plaintext length is appended to the header after the nonce prefix. v1
files still decrypt unchanged. v2 readers reject unknown flag bits.

The flag is set automatically when the input is a regular file (we
stat the open FD to avoid TOCTOU). Stdin/pipes/FIFOs encrypt as before
with the flag clear. Sequential decrypt cross-checks the produced byte
count against the committed length as defense in depth (the AEAD
already authenticates the value via header AAD, but failing before we
rename the temp file into place is preferable to failing after).

# Random-access decrypt

`fcry -d -i FILE --offset N --length L` seeks directly to the chunk(s)
covering `[N, N+L)` and decrypts only those, without scanning the
predecessors. Requires a seekable file whose header has the
length-committed flag — stdin/pipe-encrypted files cannot use this
path and the CLI rejects it with a clear error.

The chunk layout is fully determined by `chunk_size` and the committed
total length (last chunk's plaintext is
`total - (n_chunks-1)*chunk_size`; its ciphertext length is
`last_pt + 16`). Each chunk's nonce is
`make_nonce(prefix, chunk_index, is_last_chunk)` which matches what
sequential encrypt produced, so plaintext slices come out
bit-identical to a full sequential decrypt.

# Multi-threaded pipeline

New `src/pipeline.rs` implements:

  reader thread → bounded jobs channel → N AEAD workers
                → bounded results channel → writer thread

The reader stays serial (it owns the input handle and uses lookahead
to detect the last chunk). Workers parallelize the AEAD step (each
chunk is independent under STREAM). The writer holds a
`BTreeMap<u32, Vec<u8>>` reorder buffer and only flushes in counter
order. Commit is deferred to the main thread, so a failure anywhere —
reader I/O, AEAD auth, writer I/O — drops `OutSink` without renaming
the temp file into place. The
`atomic_output_no_stale_tmp_on_failure` integration test still
passes.

Channel and reorder capacities scale with worker count (`2*threads`);
peak memory is roughly `chunk_size * 4 * threads`. With 1 MiB chunks
and 8 cores that's ~32 MiB, which we accept.

Default thread count is `std::thread::available_parallelism()`;
override with `-j/--threads N`. `-j 1` keeps the original serial path.
Stdin/stdout streaming works under the parallel path because `Stdin`
(unlocked) is `Send` — only `StdinLock` isn't, so the boxed reader
wraps `Stdin` directly in a `BufReader`.

Adds `crossbeam-channel = "0.5"` for bounded MPMC. The cipher
(`XChaCha20Poly1305`) and the header AAD are shared across workers via
`Arc`; the AEAD's internal key copy is zeroized on drop as before.

# CLI surface

  -j, --threads <N>     worker thread count (default: cores)
      --offset <BYTES>  random-access decrypt: slice start
      --length <BYTES>  random-access decrypt: slice length

`--offset`/`--length` require `--decrypt` and `--input-file` (clap
enforces; we also surface a clean runtime error if only one is
supplied).

# Test plan

* `cargo test` — 5 unit + 27 integration, all green.
* New integration coverage:
  - parallel roundtrip on multi-chunk inputs (`-j 4`)
  - parallel-encrypted ciphertext decrypted serially, and vice-versa
    (output bit-identical regardless of worker count)
  - parallel pipe stdin↔stdout (asserts flag byte is 0 for stdin
    inputs — no length committed without a known size)
  - file inputs auto-commit length (asserts version=2 and flags bit 0
    set in the raw header bytes)
  - random-access slices spanning chunk-aligned, mid-chunk,
    last-chunk, and full-file ranges
  - random-access rejects out-of-range and stdin-encrypted inputs,
    accepts zero-length
  - tampering the committed length byte fails AEAD authentication
  - hand-crafted v1 header still decodes (no flag bit set)
* `cargo clippy --all-targets -- -D warnings` clean.
* `cargo +nightly fmt` clean.

Removes `TODO.md` since both deferred items are now implemented.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
 2026-05-02 20:33:00 +02:00
ddidderr f72f9034f3 feat(cli): default to interactive passphrase when no key source given 
Previously, invoking fcry without any of --raw-key, --passphrase, or
--passphrase-env produced a hard error ("must provide one of ..."). The
common, secure case (interactive TTY passphrase) thus required an
explicit flag, while the dangerous case (--raw-key on the command line)
was equally accessible.

Make the secure path the default: if no key source is specified, fall
back to PassphraseSource::Tty, which prompts on the terminal and runs
argon2id on encrypt. Explicit --passphrase still works and is now
redundant for the default invocation; --raw-key and --passphrase-env
remain unchanged and still suppress the default.

The previous "must provide one of ..." error path becomes unreachable
and is removed: the only way pw_src is None is when raw_key_str is Some,
which is handled by the existing encrypt/decrypt branches.

User-visible change: `fcry -i foo -o foo.enc` now prompts for a
passphrase instead of erroring out. Scripts that relied on the error to
detect missing arguments will instead block on a TTY read; non-TTY
callers should continue to pass --passphrase-env or --raw-key
explicitly.

Test Plan:
- `fcry -i plain -o plain.enc` prompts twice (passphrase + confirm),
  then `fcry -d -i plain.enc -o plain.out` prompts once and round-trips.
- `fcry --raw-key $(head -c32 /dev/urandom | base64) ...` still works
  and does not prompt.
- `PW=hunter2 fcry --passphrase-env PW ...` still works and does not
  prompt.
- `fcry --passphrase --raw-key ...` still rejected by clap
  (conflicts_with_all).
 2026-05-02 19:52:19 +02:00
18 changed files with 3180 additions and 936 deletions
Expand all files Collapse all files
Cargo.lock
Generated
+145 -21
View File
@@ -76,15 +76,27 @@ checksum = "3c3610892ee6e0cbce8ae2700349fcf8f98adb0dbfbee85aec3c9179d29cc072"
dependencies = [
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"blake2",
"cpufeatures",
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@@ -103,9 +115,9 @@ checksum = "2af50177e190e07a26ab74f8b1efbfe2ef87da2116221318cb1c2e82baf7de06"
[[package]]
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checksum = "b4388bee8683e3d04af747c73422af53102d2bd24d9eadb6cbc100baef4b43f8"
[[package]]
name = "blake2"
@@ -116,6 +128,20 @@ dependencies = [
"digest",
]
[[package]]
name = "blake3"
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source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "0aa83c34e62843d924f905e0f5c866eb1dd6545fc4d719e803d9ba6030371fce"
dependencies = [
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"cc",
"cfg-if",
"constant_time_eq",
"cpufeatures 0.3.0",
]
[[package]]
name = "block-buffer"
version = "0.10.4"
@@ -136,6 +162,16 @@ dependencies = [
"serde",
]
[[package]]
name = "cc"
version = "1.2.63"
source = "registry+https://github.com/rust-lang/crates.io-index"
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dependencies = [
"find-msvc-tools",
"shlex",
]
[[package]]
name = "cfg-if"
version = "1.0.4"
@@ -150,7 +186,7 @@ checksum = "c3613f74bd2eac03dad61bd53dbe620703d4371614fe0bc3b9f04dd36fe4e818"
dependencies = [
"cfg-if",
"cipher",
"cpufeatures",
"cpufeatures 0.2.17",
]
[[package]]
@@ -223,6 +259,12 @@ version = "1.0.5"
source = "registry+https://github.com/rust-lang/crates.io-index"
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[[package]]
name = "cpufeatures"
version = "0.2.17"
@@ -232,6 +274,30 @@ dependencies = [
"libc",
]
[[package]]
name = "cpufeatures"
version = "0.3.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "8b2a41393f66f16b0823bb79094d54ac5fbd34ab292ddafb9a0456ac9f87d201"
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dependencies = [
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[[package]]
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[[package]]
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@@ -284,21 +350,31 @@ checksum = "9f1f227452a390804cdb637b74a86990f2a7d7ba4b7d5693aac9b4dd6defd8d6"
[[package]]
name = "fcry"
version = "0.10.0"
version = "0.12.0"
dependencies = [
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"blake3",
"chacha20poly1305",
"clap",
"crossbeam-channel",
"getrandom 0.4.2",
"libc",
"rlimit",
"same-file",
"secrets",
"tempfile",
"unicode-normalization",
"windows-sys",
"zeroize",
]
[[package]]
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[[package]]
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@@ -350,9 +426,9 @@ dependencies = [
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[[package]]
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@@ -373,7 +449,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "d466e9454f08e4a911e14806c24e16fba1b4c121d1ea474396f396069cf949d9"
dependencies = [
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"hashbrown 0.17.1",
"serde",
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checksum = "5e5032e24019045c762d3c0f28f5b6b8bbf38563a65908389bf7978758920897"
checksum = "953f07c43838f8e6f9758cab68bf5bed85465e7587ebe0b823f1bcd81978ad3a"
[[package]]
name = "memchr"
version = "2.8.0"
version = "2.8.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "f8ca58f447f06ed17d5fc4043ce1b10dd205e060fb3ce5b979b8ed8e59ff3f79"
checksum = "6b947ae49db0d222b1dbc6b113ce7248a3fc3a6ca21b696717bfc000ba4484d8"
[[package]]
name = "once_cell"
@@ -480,7 +556,7 @@ version = "0.8.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "8159bd90725d2df49889a078b54f4f79e87f1f8a8444194cdca81d38f5393abf"
dependencies = [
"cpufeatures",
"cpufeatures 0.2.17",
"opaque-debug",
"universal-hash",
]
@@ -583,6 +659,15 @@ dependencies = [
"windows-sys",
]
[[package]]
name = "same-file"
version = "1.0.6"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "93fc1dc3aaa9bfed95e02e6eadabb4baf7e3078b0bd1b4d7b6b0b68378900502"
dependencies = [
"winapi-util",
]
[[package]]
name = "secrets"
version = "1.3.0"
@@ -632,9 +717,9 @@ dependencies = [
[[package]]
name = "serde_json"
version = "1.0.149"
version = "1.0.150"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "83fc039473c5595ace860d8c4fafa220ff474b3fc6bfdb4293327f1a37e94d86"
checksum = "e8014e44b4736ed0538adeecded0fce2a272f22dc9578a7eb6b2d9993c74cfb9"
dependencies = [
"itoa",
"memchr",
@@ -643,6 +728,12 @@ dependencies = [
"zmij",
]
[[package]]
name = "shlex"
version = "2.0.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "f8fadd59c855ef2080decdef8ff161eb6661b86933c9d82e5ba29dc602a55aba"
[[package]]
name = "strsim"
version = "0.11.1"
@@ -686,10 +777,25 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "8f50febec83f5ee1df3015341d8bd429f2d1cc62bcba7ea2076759d315084683"
[[package]]
name = "typenum"
version = "1.20.0"
name = "tinyvec"
version = "1.11.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "40ce102ab67701b8526c123c1bab5cbe42d7040ccfd0f64af1a385808d2f43de"
checksum = "3e61e67053d25a4e82c844e8424039d9745781b3fc4f32b8d55ed50f5f667ef3"
dependencies = [
"tinyvec_macros",
]
[[package]]
name = "tinyvec_macros"
version = "0.1.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "1f3ccbac311fea05f86f61904b462b55fb3df8837a366dfc601a0161d0532f20"
[[package]]
name = "typenum"
version = "1.20.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "b6f5e870be6c3b371b77fe0ee0bafb859fa4964b4404c27de1d380043c4dda20"
[[package]]
name = "unicode-ident"
@@ -697,6 +803,15 @@ version = "1.0.24"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "e6e4313cd5fcd3dad5cafa179702e2b244f760991f45397d14d4ebf38247da75"
[[package]]
name = "unicode-normalization"
version = "0.1.25"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "5fd4f6878c9cb28d874b009da9e8d183b5abc80117c40bbd187a1fde336be6e8"
dependencies = [
"tinyvec",
]
[[package]]
name = "unicode-xid"
version = "0.2.6"
@@ -814,6 +929,15 @@ version = "0.4.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
[[package]]
name = "winapi-util"
version = "0.1.11"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "c2a7b1c03c876122aa43f3020e6c3c3ee5c05081c9a00739faf7503aeba10d22"
dependencies = [
"windows-sys",
]
[[package]]
name = "winapi-x86_64-pc-windows-gnu"
version = "0.4.0"
Cargo.toml
+19 -12
View File
@@ -1,36 +1,43 @@
[package]
authors = ["ddidderr <ddidderr@paul.network>"]
edition = "2024"
name = "fcry"
version = "0.10.0"
version = "0.12.0"
edition = "2024"
license = "MIT-0"
[dependencies]
argon2 = "0.5"
blake3 = "1"
chacha20poly1305 = "0.10"
clap = { version = "4", features = ["derive"] }
crossbeam-channel = "0.5"
getrandom = { version = "0.4" }
protected-secrets = { package = "secrets", version = "1.3" }
same-file = "1"
unicode-normalization = "0.1"
zeroize = { version = "1", features = ["derive"] }
[dev-dependencies]
assert_cmd = "2"
tempfile = "3"
[target.'cfg(unix)'.dependencies]
libc = "0.2"
rlimit = "0.11"
[target.'cfg(windows)'.dependencies]
windows-sys = {version = "0.61", features = [
"Win32_System_Console",
windows-sys = {
version = "0.61",
features = [
"Win32_Foundation",
"Win32_Storage_FileSystem",
"Win32_Security",
]}
[dev-dependencies]
assert_cmd = "2"
tempfile = "3"
"Win32_Storage_FileSystem",
"Win32_System_Console",
]
}
[profile.release]
lto = false
debug = false
strip = true
lto = true
panic = "unwind"
codegen-units = 1
LICENSE
+16
View File
@@ -0,0 +1,16 @@
MIT No Attribution
Copyright 2026 fcry contributors
Permission is hereby granted, free of charge, to any person obtaining a copy of this
software and associated documentation files (the "Software"), to deal in the Software
without restriction, including without limitation the rights to use, copy, modify,
merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
LICENSE.md
-675
View File
@@ -1,675 +0,0 @@
### GNU GENERAL PUBLIC LICENSE
Version 3, 29 June 2007
Copyright (C) 2007 Free Software Foundation, Inc.
<https://fsf.org/>
Everyone is permitted to copy and distribute verbatim copies of this
license document, but changing it is not allowed.
### Preamble
The GNU General Public License is a free, copyleft license for
software and other kinds of works.
The licenses for most software and other practical works are designed
to take away your freedom to share and change the works. By contrast,
the GNU General Public License is intended to guarantee your freedom
to share and change all versions of a program--to make sure it remains
free software for all its users. We, the Free Software Foundation, use
the GNU General Public License for most of our software; it applies
also to any other work released this way by its authors. You can apply
it to your programs, too.
When we speak of free software, we are referring to freedom, not
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To protect your rights, we need to prevent others from denying you
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For example, if you distribute copies of such a program, whether
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Developers that use the GNU GPL protect your rights with two steps:
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Some devices are designed to deny users access to install or run
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The precise terms and conditions for copying, distribution and
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### TERMS AND CONDITIONS
#### 0. Definitions.
"This License" refers to version 3 of the GNU General Public License.
"Copyright" also means copyright-like laws that apply to other kinds
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"The Program" refers to any copyrightable work licensed under this
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To "modify" a work means to copy from or adapt all or part of the work
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A "covered work" means either the unmodified Program or a work based
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To "propagate" a work means to do anything with it that, without
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#### 1. Source Code.
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#### 2. Basic Permissions.
All rights granted under this License are granted for the term of
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#### 3. Protecting Users' Legal Rights From Anti-Circumvention Law.
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- d) If the work has interactive user interfaces, each must display
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#### 7. Additional Terms.
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License by making exceptions from one or more of its conditions.
Additional permissions that are applicable to the entire Program shall
be treated as though they were included in this License, to the extent
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Additional terms, permissive or non-permissive, may be stated in the
form of a separately written license, or stated as exceptions; the
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#### 8. Termination.
You may not propagate or modify a covered work except as expressly
provided under this License. Any attempt otherwise to propagate or
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this License (including any patent licenses granted under the third
paragraph of section 11).
However, if you cease all violation of this License, then your license
from a particular copyright holder is reinstated (a) provisionally,
unless and until the copyright holder explicitly and finally
terminates your license, and (b) permanently, if the copyright holder
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your receipt of the notice.
Termination of your rights under this section does not terminate the
licenses of parties who have received copies or rights from you under
this License. If your rights have been terminated and not permanently
reinstated, you do not qualify to receive new licenses for the same
material under section 10.
#### 9. Acceptance Not Required for Having Copies.
You are not required to accept this License in order to receive or run
a copy of the Program. Ancillary propagation of a covered work
occurring solely as a consequence of using peer-to-peer transmission
to receive a copy likewise does not require acceptance. However,
nothing other than this License grants you permission to propagate or
modify any covered work. These actions infringe copyright if you do
not accept this License. Therefore, by modifying or propagating a
covered work, you indicate your acceptance of this License to do so.
#### 10. Automatic Licensing of Downstream Recipients.
Each time you convey a covered work, the recipient automatically
receives a license from the original licensors, to run, modify and
propagate that work, subject to this License. You are not responsible
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sale, or importing the Program or any portion of it.
#### 11. Patents.
A "contributor" is a copyright holder who authorizes use under this
License of the Program or a work on which the Program is based. The
work thus licensed is called the contributor's "contributor version".
A contributor's "essential patent claims" are all patent claims owned
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README.md
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# fcry - [f]ile[cry]pt
A file en-/decryption tool for easy use.
# fcry - filecrypt
Currently `fcry` uses `ChaCha20Poly1305` ([RFC 8439](https://datatracker.ietf.org/doc/html/rfc8439)) as [AEAD](https://en.wikipedia.org/wiki/Authenticated_encryption) cipher provided by the [chacha20poly1305](https://docs.rs/chacha20poly1305/latest/chacha20poly1305/) crate.
`fcry` encrypts and decrypts files with an authenticated chunked format. New
files use XChaCha20-Poly1305 in a STREAM-style construction: a 19-byte random
nonce prefix, a 32-bit chunk counter, and a last-chunk bit form each 24-byte
XChaCha nonce. Every chunk authenticates the full file header as AEAD
associated data.
## Status
Currently `fcry` is __not thoroughly tested__ and in __early stages of development__.
There is a chance, that something is broken as of now.
Encryption __seems__ to work, but due to a possible lack of understanding of some underlying methods
(or misinterpretation) it could theoretically be not effective at all.
The tool is intended for local file encryption, scripted backups, and
streaming-friendly decrypts. It is not a general archive format, does not hide
file size, and does not protect plaintext after another process has received
it.
See [TODO.md](/ddidderr/fcry/src/branch/main/TODO.md) for further information.
## Usage
Encrypt with an interactive passphrase:
```sh
fcry -i plain.bin -o plain.bin.fcry --passphrase
```
Decrypt with the same passphrase:
```sh
fcry -d -i plain.bin.fcry -o plain.bin --passphrase
```
Use a raw 32-byte key file instead of a passphrase:
```sh
fcry -i plain.bin -o plain.bin.fcry --key-file key.bin
fcry -d -i plain.bin.fcry -o plain.bin --key-file key.bin
```
For non-interactive passphrase use:
```sh
FCRY_PASSWORD='correct horse battery staple' \
fcry -i plain.bin -o plain.bin.fcry --passphrase-env FCRY_PASSWORD
```
`--passphrase-env` is useful for automation, but the environment variable can
remain visible to the current process environment and platform tooling. Prefer
interactive entry or a protected key file when possible.
## Safety Properties
- File outputs are written to private, randomly named temporary files and are
renamed into place only after encryption or decryption succeeds. Existing
outputs require `--force`, except for the self-replacement case that is
handled through the temporary file.
- New passphrase encryptions use Argon2id by default with 1024 MiB of memory,
2 passes, and 4 lanes. Passphrases must be non-empty and at least 12 UTF-8
bytes unless `--allow-weak-kdf` is explicitly supplied for tests or legacy
interop.
- Decryption enforces a memory ceiling for Argon2id headers. The default cap is
the lower of 4096 MiB, the architecture limit, and available Linux memory
when that can be detected. Override it with `--max-argon-memory-mib` only for
files you trust.
- Chunk size is bounded to `1..=64 MiB`. Worker threads are capped at 256, and
the pipeline bounds in-flight chunk memory.
- v3 files carry a key commitment derived from the stretched key and committed
header fields. This gives a fast, clear wrong-key failure before chunk
processing and prevents stripping or downgrading the commitment without
authentication failure.
- On Unix, `fcry` makes a best-effort call to disable core dumps for the process
before handling secrets.
## Format
The current on-disk format version is v3.
```text
magic "fcry" 4 bytes
version u8 1
alg_id u8 1 (1 = XChaCha20-Poly1305)
flags u8 1
reserved u8 1 (must be 0)
chunk_size u32 LE 4
kdf_id u8 1 (0 = raw key, 1 = Argon2id)
kdf_params variable
nonce_prefix [u8; 19]
plaintext_length u64 LE only when flags bit 0 is set
key_commitment [u8; 32] only when flags bit 1 is set
ciphertext chunks each plaintext chunk plus a 16-byte Poly1305 tag
```
The encoded header is AEAD associated data for every chunk. Changing the chunk
size, KDF parameters, nonce prefix, committed plaintext length, key commitment,
or other header bytes causes authentication failure.
Version history:
- v1: no flags and no committed plaintext length.
- v2: adds the length-committed flag and optional `plaintext_length`.
- v3: requires the key-commitment flag and stores the 32-byte key commitment.
Regular file encryption commits `plaintext_length` in the header. Stdin
encryption cannot know the final length up front, so stdin-produced files do
not support random-access decrypt.
## Streaming And Ranges
Normal decrypt-to-stdout emits each plaintext chunk after that chunk has
authenticated. This means a truncated ciphertext can produce an authentic
prefix on stdout before the final truncation error is reported. That is
inherent to chunked streaming AE when bytes are released immediately.
Use `--buffer-verify` when decrypting to stdout if downstream consumers must
not see any plaintext until the whole file has authenticated:
```sh
fcry -d -i plain.bin.fcry --passphrase --buffer-verify > plain.bin
```
`--buffer-verify` writes plaintext to a private temporary file first, verifies
the complete ciphertext, and copies to stdout only after success. File outputs
already get atomic temporary-file behavior, so `--buffer-verify` is only valid
for decrypt-to-stdout.
Random-access decrypt requires `--decrypt`, `--input-file`, `--offset`, and
`--length`, and the input must have a length-committed header:
```sh
fcry -d -i plain.bin.fcry --passphrase --offset 1048576 --length 4096 > slice.bin
```
A successful range decrypt authenticates the requested chunks and header. It
does not prove that the rest of the file is present or untampered. Use a full
decrypt when you need whole-file integrity. `--length 0` is rejected because it
would authenticate no chunks.
## Threat Model
`fcry` aims to provide confidentiality and integrity for file contents against
an attacker who can read, copy, truncate, replace, or modify ciphertext files
after encryption. With passphrase mode, offline guessing is still possible; the
Argon2id parameters make each guess expensive but cannot make a weak passphrase
safe.
The format authenticates all header fields that affect decryption, including
KDF parameters, chunk size, nonce prefix, committed plaintext length, and key
commitment. Unknown header flags and unsupported algorithms are rejected.
The following are explicit non-goals:
- Hiding plaintext length or access patterns. `plaintext_length` is cleartext
for regular-file encryptions, and ciphertext length already reveals an
approximate plaintext size. There is no padding scheme.
- Preventing plaintext exposure after successful decrypt. Plaintext written to
stdout, files, pipes, shell history, terminals, swap, backups, or downstream
tools is outside `fcry`'s control.
- Protecting plaintext chunk buffers from every local memory-forensics route.
Keys and passphrases use protected/zeroizing storage where practical, and
chunk buffers are zeroized on drop, but decrypted plaintext necessarily exists
in ordinary process memory while being processed.
- Disabling Windows Error Reporting or minidumps. Unlike Unix core dumps, those
are controlled by per-machine Windows policy; `fcry` records this as an
operator/deployment responsibility rather than changing host-wide policy.
- Recovering from loss of the passphrase or raw key file. There is no escrow or
backdoor.
## Operational Notes
- Keep backups of important plaintext until you have verified the encrypted
file and your recovery path.
- Store raw key files with restrictive permissions. On Unix, `fcry` warns when
a key file is group/world accessible.
- Use `--allow-weak-kdf` only for tests or compatibility with old intentionally
weak files.
- Use `--temp-dir` when the default temporary-file location is not acceptable
for decrypt-to-stdout buffering or output staging.
REVIEW_SECURITY_FABLE_5.md
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I read every file, traced the STREAM construction, the parallel pipeline's ordering/cancellation logic, and the I/O paths, and cross-checked the existing `REVIEW_SECURITY_GPT5.5.md`. Verdict first: **the cryptographic core is correct.** The problems are in input validation and file handling, and two of them can destroy user data without any attacker involved.
## What's cryptographically sound (verified, not assumed)
The construction is the STREAM online-AE scheme (Hoang–Reyhanitabar–Rogaway–Vizár), the same shape age and Tink use: XChaCha20-Poly1305, 19-byte random prefix + 4-byte BE counter + last-block byte = 24-byte nonce, full header as AAD on every chunk. I checked the failure modes individually:
- **Truncation** at a chunk boundary: the new final chunk was encrypted with `last=false`, decryptor computes the nonce with `last=true` → tag failure. Mid-chunk truncation and appended garbage also fail (a trailing partial read flips the real last chunk to `Normal`, wrong nonce again).
- **Reorder/duplicate/drop** of interior chunks: counter is in the nonce → fails.
- **Cross-file chunk splicing** under the same key: per-file random 19-byte prefix plus per-file header AAD → fails.
- **Header tampering** (chunk_size, KDF params, version, flags, length): header is the AAD → every chunk fails. The v1 regression test shows you understood the encode-stability trap; `version` is preserved as-read, so no downgrade is possible.
- **Empty plaintext** is authenticated via an explicit empty last chunk; a ciphertext that is only a header errors instead of silently producing an empty file.
- **Counter overflow** is checked (`bump_counter`), nonce prefix collision across files is 2⁻¹⁵² territory, `getrandom` failure propagates instead of falling back.
- **Parallel pipeline**: I traced the permit/reorder/cancel logic. The writer only writes in counter order, a failed chunk leaves `pending` non-empty → error, and `commit()` is only reachable after all three thread groups joined with no error. There is no path where a tampered chunk ends up in a committed file output.
The README's worry that it "could theoretically be not effective at all" is unfounded for the construction itself.
## New findings (not in the GPT-5.5 review)
**1. High — `--chunk-size 0` with stdin silently discards all data.**
There is no encrypt-side validation of `chunk_size`. With `0`, `AheadReader` gets capacity 0, `read_until_full` on an empty slice returns `Ok(0)` immediately (BufReader fills its internal buffer, then copies 0 bytes), so the very first `read_ahead` returns `Empty`. `encrypt` then writes a single authenticated empty last chunk and **commits successfully**. For a regular file input, the `plaintext_length` cross-check saves you (`committed != 0` → error before commit). For `cat backup.tar | fcry --chunk-size 0 ...` there is no committed length, so you get a valid-looking output file that encrypts zero bytes — and since `Header::read` rejects `chunk_size == 0`, the file is additionally undecryptable. If the user deletes the source afterwards, the data is gone. Fix: validate `chunk_size` in `run()` (reject 0, set a sane max), independent of the header-side check.
**2. High — `OutSink` can destroy the input file before reading it.**
`fcry -d -i backup.fcry.tmp -o backup.fcry` computes `tmp_path = backup.fcry.tmp` and calls `File::create` on it — which truncates your encrypted input to zero bytes before any read happens beyond what `BufReader` already buffered. The run then fails with "truncated ciphertext", but the original file is already destroyed. This is the sharpest consequence of the predictable `<name>.tmp` scheme; the GPT review only covered the symlink and permissions angle (both of which I confirm: `File::create` follows symlinks, and the decrypted plaintext gets umask-default 0644). One fix kills all three: `O_CREAT|O_EXCL` with a random suffix (`tempfile::NamedTempFile::new_in(parent)` + `persist`), mode 0600 for decrypt output, and optionally refuse to clobber an existing `final_path` without `--force`.
**3. Medium/Low — no key commitment.**
ChaCha20-Poly1305 is not key-committing: a ciphertext chunk can be constructed that authenticates under multiple keys (invisible-salamander / partitioning-oracle class). Practical exploitability here is low — it requires a victim decrypting attacker-supplied files and leaking success/failure, and each candidate key costs a full Argon2 run — but fixing it is nearly free and buys you something users feel daily: right now a wrong passphrase burns 1 GiB / seconds of Argon2 and then fails with the exact same `aead::Error` as a corrupted file. Derive a key-check value from the *stretched* key (e.g. first 16 bytes of BLAKE2b(key, "fcry-kcv") in the header, or encrypt a fixed zero block as chunk −1) and you get both key commitment in practice and a clean "wrong passphrase" vs. "corrupt file" distinction. Deriving it from the Argon2 output means it does not cheapen offline guessing — an attacker with the file can already test guesses against chunk 0's tag at identical cost.
**4. Low — passphrase byte-encoding is not portable.**
The Unix path reads UTF-8 bytes from `/dev/tty`. The Windows path reads bytes via `ReadFile` on `CONIN$`, which yields the console's ANSI/OEM codepage — for any non-ASCII passphrase those byte sequences differ, and Argon2 hashes bytes. A file encrypted on Linux with `pässwört` can be undecryptable on Windows and vice versa. There's also no Unicode normalization (NFC vs. NFD — macOS input methods differ from Linux). Either read UTF-16 via `ReadConsoleW` and convert to UTF-8 + normalize to NFC on all platforms, or document ASCII-only passphrases.
**5. Low — unchecked `u64` multiply in `decrypt_range`.**
`chunk_offset = header_len + i * cipher_chunk`: with a forged header committing `plaintext_length` near 2⁶⁴ and a small `chunk_size`, `i` can approach 2³²−1 while `cipher_chunk` is 2³²+15, and the product wraps in release (your release profile has default `overflow-checks = false`). The result is a seek to a wrong offset and a guaranteed tag failure, so it's not exploitable — but it's pre-authentication arithmetic on attacker bytes and should be `checked_mul`/`checked_add` like the rest of that function already is.
## GPT-5.5 findings I confirm, with sharpening
- **Pre-auth resource consumption from header fields** — real, and worse in the parallel path than stated: the pipeline reader allocates a fresh `vec![0u8; chunk_sz]` per job with up to `4 × threads` chunks in flight, so a forged `chunk_size = u32::MAX` on a 16-core box attempts ~64 × 4 GiB before any tag is checked. Argon2 `m_cost` from the header can demand up to 4 TiB; the argon2 crate's block allocation will abort the process on OOM. Cap both at parse time (e.g. chunk_size ≤ 256 MiB, m_cost ≤ some GiB ceiling with an override flag).
- **Stdout streams authenticated-but-possibly-truncated prefixes** — correct, and inherent to chunked streaming AE; every released byte is authentic, but a downstream consumer can act on a verified prefix before the truncation error lands. Document it prominently; a `--buffer-verify` mode is the only real alternative.
- **`--length 0` range decrypt succeeds with zero authentication** (doesn't even prove the key) and range success ≠ whole-file integrity — both correct as written.
- **No floors on passphrase/KDF choices** — confirmed; empty passphrase plus `--argon-memory 1 --argon-passes 1` is accepted (the argon2 crate clamps only at m_cost ≥ 8·p_cost).
- **`--raw-key` design** — confirmed; beyond the `/proc/*/cmdline` leak, the keyspace is restricted to valid UTF-8 of exactly 32 bytes, which both blocks legitimate random keys (~⅓ of random 32-byte strings aren't UTF-8, and clap's `String` parsing rejects them) and invites typing a 32-char password with zero stretching. Hex/base64 from a file or fd is the right replacement.
- **Plaintext chunk buffers unprotected** — confirmed (plain `Vec<u8>` through channels, no zeroize/mlock). I'd rank this lower than the review does: the plaintext's home is the disk anyway; the meaningful residual exposure is swap, and core dumps are already disabled on Unix.
Two more one-liners: `commit()` doesn't fsync the parent directory after the rename, so a crash right after a successful run can lose the rename (durability, not confidentiality); and `plaintext_length` sits in cleartext in the header, which leaks nothing beyond what the unpadded ciphertext length already reveals — but if you ever care about size metadata, that's where a padding scheme (à la covert padding / PADMÉ) would slot in.
If you want, I can write the patch set for the top items — chunk-size validation, the `OutSink` rework with `create_new` + random suffix + 0600, and header-side caps are all small, self-contained diffs.
REVIEW_SECURITY_GPT5.5.md
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# Findings
- High: attacker-controlled headers can cause large pre-auth resource use. chunk_size and Argon2 params are read before any AEAD tag is verified, then used for allocation/KDF work. A malicious file can request huge buffers or Argon2 memory/time. See
src/header.rs:107, src/crypto.rs:54, src/crypto.rs:189. Add strict max caps before allocation/KDF.
- High: output temp file handling is unsafe in hostile directories. Output uses predictable <name>.tmp plus File::create, which follows symlinks and truncates existing files. Decrypted plaintext may also be created with permissive umask-derived
permissions. See src/utils.rs:71. Use randomized create_new temp files, 0600 permissions for plaintext, and safe persist semantics.
- Medium: stdout decrypt streams verified chunks before whole-file success. File output is protected by temp-file commit, but stdout cannot roll back. A truncated valid-prefix ciphertext can emit authentic but incomplete plaintext before the final
error. See src/crypto.rs:217 and src/pipeline.rs:348. Document this sharply or add a “verify before stdout” mode.
- Medium: random-access decrypt authenticates only requested chunks. That is expected for range reads, but users may mistake success for whole-file integrity. --length 0 succeeds without authenticating any chunk, so it does not prove the key or file is
valid. See src/crypto.rs:307.
- Medium: weak passphrase choices are accepted. Empty/very short passphrases and very low Argon2 settings are possible. Defaults are strong, but user-supplied weak parameters are stored and honored. See src/main.rs:55, src/secrets.rs:172. Enforce
floors or require an explicit insecure flag.
- Medium: raw-key UX invites misuse. --raw-key is a UTF-8 command-line string, visible in process listings, and not truly arbitrary 32 raw bytes. It is documented as dangerous, but still a first-class CLI path. See src/main.rs:37. Prefer hex/base64
from file/stdin/fd, or make raw key testing-only.
- Medium: plaintext buffers are not zeroized. Keys/passphrases get protected handling, but plaintext/ciphertext chunk buffers are ordinary Vec<u8> and may leave sensitive plaintext in heap memory after decrypt/encrypt. See src/crypto.rs:127, src/
crypto.rs:210, src/pipeline.rs:48.
- Medium/Low: unchecked arithmetic and unbounded CLI knobs remain. chunk_size + TAG_LEN, random-access offsets, huge -j values, and release overflow behavior deserve explicit checked math and caps. See src/crypto.rs:190, src/pipeline.rs:61,
Cargo.toml:32.
- Low: platform hardening is partial. Unix core dumps are disabled, which is good, but Windows crash dumps are not addressed, and non-secret plaintext buffers are not protected from swap/dumps. See src/main.rs:141.
- Low: custom crypto framing needs a written threat model and test vectors. The construction is reasonable, but custom file formats are easy to misuse over time. README still says the tool is early and not thoroughly tested, and links a missing TODO.
See README.md:6.
Good Signs
The core AEAD choice is solid: XChaCha20-Poly1305 with random nonce prefix, per-chunk counters, full header as AAD, and an authenticated final chunk. The code also commits plaintext length for regular files, rejects unknown header flags, uses Argon2id
for passphrases, disables Unix core dumps, and avoids committing partial file outputs on failure.
Post-Quantum
For the current symmetric-only design, there is no RSA/ECC public-key crypto to replace. A 256-bit symmetric key is generally the right shape for post-quantum resistance; Grover-style search still leaves roughly 128-bit security. The weak link is
password entropy, not the AEAD.
If you add recipient/public-key encryption or signatures, use standardized PQC: NIST finalized FIPS 203 ML-KEM, FIPS 204 ML-DSA, and FIPS 205 SLH-DSA in 2024, and recommends migration planning now. Sources: NIST FIPS announcement
(<https://www.nist.gov/news-events/news/2024/08/announcing-approval-three-federal-information-processing-standards-fips>), NIST PQC project (<https://www.nist.gov/programs-projects/post-quantum-cryptography>).
TODO.md
-3
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@@ -1,3 +0,0 @@
**Deferred to follow-up commits** (in order):
1. Multi-threaded pipeline (worker pool + ordered writer)
2. Length-committed mode + random-access decrypt fast path for files
src/crypto.rs
+483 -38
View File
@@ -1,21 +1,29 @@
// SPDX-License-Identifier: GPL-3.0-only
// SPDX-License-Identifier: MIT-0
use chacha20poly1305::{KeyInit, XChaCha20Poly1305, XNonce, aead::AeadInPlace};
use std::io::Write;
use std::fs::File;
use std::io::{BufReader, Read, Seek, SeekFrom, Write};
use std::sync::Arc;
use crate::error::*;
use crate::header::{AlgId, Header, KdfParams, NONCE_PREFIX_LEN, TAG_LEN};
use crate::header::{
AlgId, FLAG_KEY_COMMITTED, FLAG_LENGTH_COMMITTED, Header, KdfParams, NONCE_PREFIX_LEN, TAG_LEN,
VERSION_CURRENT,
};
use crate::pipeline;
use crate::policy;
use crate::reader::{AheadReader, ReadInfoChunk};
use crate::secrets::{SecretBytes32, SecretVec};
use crate::utils::*;
use zeroize::Zeroizing;
/// XChaCha20Poly1305 nonce: 24 bytes total. STREAM splits the trailing 5 bytes
/// into a 4-byte big-endian counter and a 1-byte "last block" flag.
const NONCE_LEN: usize = 24;
const COUNTER_LEN: usize = 4;
pub(crate) const NONCE_LEN: usize = 24;
pub(crate) const COUNTER_LEN: usize = 4;
const _: () = assert!(NONCE_PREFIX_LEN + COUNTER_LEN + 1 == NONCE_LEN);
fn make_nonce(prefix: &[u8; NONCE_PREFIX_LEN], counter: u32, last: bool) -> XNonce {
pub(crate) fn make_nonce(prefix: &[u8; NONCE_PREFIX_LEN], counter: u32, last: bool) -> XNonce {
let mut n = [0u8; NONCE_LEN];
n[..NONCE_PREFIX_LEN].copy_from_slice(prefix);
n[NONCE_PREFIX_LEN..NONCE_PREFIX_LEN + COUNTER_LEN].copy_from_slice(&counter.to_be_bytes());
@@ -35,7 +43,7 @@ pub fn derive_key(
match kdf {
KdfParams::Raw => {
let raw =
raw_key.ok_or_else(|| FcryError::Format("raw kdf requires --raw-key".into()))?;
raw_key.ok_or_else(|| FcryError::Format("raw kdf requires --key-file".into()))?;
raw.with_array(|raw| out.with_mut_array(|out| out.copy_from_slice(raw)));
}
KdfParams::Argon2id {
@@ -55,53 +63,139 @@ pub fn derive_key(
Ok(out)
}
/// Build the AEAD cipher from the protected key. The cipher holds an
/// unprotected copy of the key while alive; `chacha20poly1305` zeroizes that
/// copy on drop. Wrapping in `Arc` lets us share it across worker threads.
fn build_aead(key: &SecretBytes32) -> Arc<XChaCha20Poly1305> {
Arc::new(key.with_array(|key| XChaCha20Poly1305::new(key.into())))
}
fn compute_key_commitment(key: &SecretBytes32, header: &Header) -> [u8; 32] {
key.with_array(|key| {
let mut hasher = blake3::Hasher::new_keyed(key);
hasher.update(b"fcry-kcv-v3");
hasher.update(&[0]);
hasher.update(&header.commitment_input_encoding());
*hasher.finalize().as_bytes()
})
}
fn verify_key_commitment(header: &Header, key: &SecretBytes32) -> Result<(), FcryError> {
let Some(expected) = header.key_commitment else {
return Ok(());
};
let actual = compute_key_commitment(key, header);
let mut diff = 0u8;
for (a, b) in actual.iter().zip(expected.iter()) {
diff |= a ^ b;
}
if diff == 0 {
Ok(())
} else {
Err(FcryError::WrongKey)
}
}
/// Bump the per-chunk counter; surface a domain error on overflow rather than
/// panicking on debug or wrapping in release.
pub(crate) fn bump_counter(counter: u32) -> Result<u32, FcryError> {
counter
.checked_add(1)
.ok_or_else(|| FcryError::Format("STREAM counter overflow (input too large)".into()))
}
#[allow(dead_code)]
pub fn encrypt<S: AsRef<str>>(
input_file: Option<S>,
output_file: Option<S>,
key: &SecretBytes32,
chunk_size: u32,
kdf: KdfParams,
threads: usize,
) -> Result<(), FcryError> {
let chunk_sz = chunk_size as usize;
let mut f_plain = AheadReader::from(open_input(input_file)?, chunk_sz);
let mut f_encrypted = OutSink::open(output_file)?;
encrypt_with_output_options(
input_file,
output_file,
key,
chunk_size,
kdf,
threads,
&OutSinkOptions::default(),
)
}
pub fn encrypt_with_output_options<S: AsRef<str>>(
input_file: Option<S>,
output_file: Option<S>,
key: &SecretBytes32,
chunk_size: u32,
kdf: KdfParams,
threads: usize,
output_options: &OutSinkOptions,
) -> Result<(), FcryError> {
let chunk_sz = policy::validate_chunk_size(chunk_size)?;
let input = open_input(input_file)?;
let plaintext_length = input.length;
let mut f_plain = AheadReader::from(input.reader, chunk_sz);
let mut f_encrypted = OutSink::open_with_options(output_file, output_options)?;
let mut nonce_prefix = [0u8; NONCE_PREFIX_LEN];
getrandom::fill(&mut nonce_prefix)?;
let header = Header {
let flags = if plaintext_length.is_some() {
FLAG_LENGTH_COMMITTED
} else {
0
} | FLAG_KEY_COMMITTED;
let mut header = Header {
version: VERSION_CURRENT,
alg: AlgId::XChaCha20Poly1305,
flags: 0,
flags,
chunk_size,
kdf,
nonce_prefix,
plaintext_length,
key_commitment: None,
};
let aad = header.encode();
header.key_commitment = Some(compute_key_commitment(key, &header));
let aad = Arc::new(header.encode());
f_encrypted.write_all(&aad)?;
// The AEAD keeps its own unprotected key copy while the loop runs.
// chacha20poly1305 zeroizes that copy on drop.
let aead = key.with_array(|key| XChaCha20Poly1305::new(key.into()));
let aead = build_aead(key);
let mut buf = vec![0u8; chunk_sz];
if threads > 1 {
return pipeline::encrypt_parallel(
f_plain,
f_encrypted,
aead,
aad,
nonce_prefix,
chunk_sz,
threads,
plaintext_length,
);
}
let mut buf = Zeroizing::new(vec![0u8; chunk_sz]);
let mut counter: u32 = 0;
let mut bytes_seen: u64 = 0;
loop {
match f_plain.read_ahead(&mut buf)? {
ReadInfoChunk::Normal(_) => {
let nonce = make_nonce(&nonce_prefix, counter, false);
aead.encrypt_in_place(&nonce, &aad, &mut buf)?;
aead.encrypt_in_place(&nonce, &aad, &mut *buf)?;
f_encrypted.write_all(&buf)?;
buf.truncate(chunk_sz);
counter = counter.checked_add(1).ok_or_else(|| {
FcryError::Format("STREAM counter overflow (input too large)".into())
})?;
bytes_seen = policy::checked_count_add(bytes_seen, chunk_sz, "bytes read")?;
counter = bump_counter(counter)?;
}
ReadInfoChunk::Last(n) => {
buf.truncate(n);
let nonce = make_nonce(&nonce_prefix, counter, true);
aead.encrypt_in_place(&nonce, &aad, &mut buf)?;
aead.encrypt_in_place(&nonce, &aad, &mut *buf)?;
f_encrypted.write_all(&buf)?;
bytes_seen = policy::checked_count_add(bytes_seen, n, "bytes read")?;
break;
}
ReadInfoChunk::Empty => {
@@ -109,58 +203,125 @@ pub fn encrypt<S: AsRef<str>>(
// authenticates the (empty) stream rather than silently producing nothing.
buf.clear();
let nonce = make_nonce(&nonce_prefix, counter, true);
aead.encrypt_in_place(&nonce, &aad, &mut buf)?;
aead.encrypt_in_place(&nonce, &aad, &mut *buf)?;
f_encrypted.write_all(&buf)?;
break;
}
}
}
if let Some(committed) = plaintext_length
&& committed != bytes_seen
{
// Defense in depth: the input changed between stat and EOF. The
// committed length is part of the AEAD AAD, so any decrypter would
// also surface this, but we prefer to fail before publishing the file.
return Err(FcryError::Format(format!(
"input length changed during encryption: committed {committed}, read {bytes_seen}"
)));
}
f_encrypted.commit()?;
Ok(())
}
#[allow(dead_code)]
pub fn decrypt<S: AsRef<str>>(
input_file: Option<S>,
output_file: Option<S>,
raw_key: Option<&SecretBytes32>,
passphrase: Option<&SecretVec>,
threads: usize,
) -> Result<(), FcryError> {
let mut reader = open_input(input_file)?;
let header = Header::read(&mut reader)?;
let aad = header.encode();
decrypt_with_argon_cap(
input_file,
output_file,
raw_key,
passphrase,
threads,
policy::default_argon_decrypt_cap_mib(),
)
}
#[allow(dead_code)]
pub fn decrypt_with_argon_cap<S: AsRef<str>>(
input_file: Option<S>,
output_file: Option<S>,
raw_key: Option<&SecretBytes32>,
passphrase: Option<&SecretVec>,
threads: usize,
max_argon_memory_mib: u32,
) -> Result<(), FcryError> {
decrypt_with_output_options(
input_file,
output_file,
raw_key,
passphrase,
threads,
max_argon_memory_mib,
&OutSinkOptions::default(),
)
}
pub fn decrypt_with_output_options<S: AsRef<str>>(
input_file: Option<S>,
output_file: Option<S>,
raw_key: Option<&SecretBytes32>,
passphrase: Option<&SecretVec>,
threads: usize,
max_argon_memory_mib: u32,
output_options: &OutSinkOptions,
) -> Result<(), FcryError> {
let mut reader = open_input(input_file)?.reader;
let header = Header::read_with_argon_cap(&mut reader, max_argon_memory_mib)?;
let aad = Arc::new(header.encode());
let key = derive_key(&header.kdf, raw_key, passphrase)?;
verify_key_commitment(&header, &key)?;
let chunk_sz = header.chunk_size as usize;
let cipher_chunk = chunk_sz + TAG_LEN;
let chunk_sz = policy::validate_chunk_size(header.chunk_size)?;
let cipher_chunk = policy::cipher_chunk_len(chunk_sz)?;
let mut f_encrypted = AheadReader::from(reader, cipher_chunk);
let mut f_plain = OutSink::open(output_file)?;
let mut f_plain = OutSink::open_with_options(output_file, output_options)?;
// The AEAD keeps its own unprotected key copy while the loop runs.
// chacha20poly1305 zeroizes that copy on drop.
let aead = key.with_array(|key| XChaCha20Poly1305::new(key.into()));
let aead = build_aead(&key);
let mut buf = vec![0u8; cipher_chunk];
if threads > 1 {
return pipeline::decrypt_parallel(
f_encrypted,
f_plain,
aead,
aad,
header.nonce_prefix,
cipher_chunk,
threads,
header.plaintext_length,
);
}
let mut buf = Zeroizing::new(vec![0u8; cipher_chunk]);
let mut counter: u32 = 0;
let mut bytes_written: u64 = 0;
loop {
match f_encrypted.read_ahead(&mut buf)? {
ReadInfoChunk::Normal(_) => {
let nonce = make_nonce(&header.nonce_prefix, counter, false);
aead.decrypt_in_place(&nonce, &aad, &mut buf)?;
aead.decrypt_in_place(&nonce, &aad, &mut *buf)?;
f_plain.write_all(&buf)?;
bytes_written =
policy::checked_count_add(bytes_written, buf.len(), "bytes written")?;
buf.resize(cipher_chunk, 0);
counter = counter
.checked_add(1)
.ok_or_else(|| FcryError::Format("STREAM counter overflow".into()))?;
counter = bump_counter(counter)?;
}
ReadInfoChunk::Last(n) => {
buf.truncate(n);
let nonce = make_nonce(&header.nonce_prefix, counter, true);
aead.decrypt_in_place(&nonce, &aad, &mut buf)?;
aead.decrypt_in_place(&nonce, &aad, &mut *buf)?;
f_plain.write_all(&buf)?;
bytes_written =
policy::checked_count_add(bytes_written, buf.len(), "bytes written")?;
break;
}
ReadInfoChunk::Empty => {
@@ -171,6 +332,290 @@ pub fn decrypt<S: AsRef<str>>(
}
}
if let Some(committed) = header.plaintext_length
&& committed != bytes_written
{
return Err(FcryError::Format(format!(
"decrypted length {bytes_written} disagrees with committed {committed}"
)));
}
f_plain.commit()?;
Ok(())
}
/// Random-access decrypt of a byte range. Requires a seekable input file
/// whose header has `FLAG_LENGTH_COMMITTED` set, so we know exactly where
/// each ciphertext chunk lives and which chunk is the last (its nonce uses
/// the STREAM last-block flag).
#[allow(dead_code)]
pub fn decrypt_range<S: AsRef<str>>(
input_file: &str,
output_file: Option<S>,
raw_key: Option<&SecretBytes32>,
passphrase: Option<&SecretVec>,
offset: u64,
length: u64,
) -> Result<(), FcryError> {
decrypt_range_with_argon_cap(
input_file,
output_file,
raw_key,
passphrase,
offset,
length,
policy::default_argon_decrypt_cap_mib(),
)
}
#[allow(dead_code)]
pub fn decrypt_range_with_argon_cap<S: AsRef<str>>(
input_file: &str,
output_file: Option<S>,
raw_key: Option<&SecretBytes32>,
passphrase: Option<&SecretVec>,
offset: u64,
length: u64,
max_argon_memory_mib: u32,
) -> Result<(), FcryError> {
decrypt_range_with_output_options(
input_file,
output_file,
raw_key,
passphrase,
offset,
length,
max_argon_memory_mib,
&OutSinkOptions::default(),
)
}
#[allow(clippy::too_many_arguments)]
pub fn decrypt_range_with_output_options<S: AsRef<str>>(
input_file: &str,
output_file: Option<S>,
raw_key: Option<&SecretBytes32>,
passphrase: Option<&SecretVec>,
offset: u64,
length: u64,
max_argon_memory_mib: u32,
output_options: &OutSinkOptions,
) -> Result<(), FcryError> {
if length == 0 {
return Err(FcryError::Format("--length 0 is not allowed".into()));
}
let file = File::open(input_file)?;
let mut reader = BufReader::new(file);
let header = Header::read_with_argon_cap(&mut reader, max_argon_memory_mib)?;
let aad = header.encode();
let header_len = aad.len() as u64;
let total = header.plaintext_length.ok_or_else(|| {
FcryError::Format(
"random-access decrypt requires a length-committed header (encrypt from a regular file)".into(),
)
})?;
let end = offset
.checked_add(length)
.ok_or_else(|| FcryError::Format("offset + length overflows u64".into()))?;
if end > total {
return Err(FcryError::Format(format!(
"range [{offset}, {end}) exceeds plaintext length {total}"
)));
}
let key = derive_key(&header.kdf, raw_key, passphrase)?;
verify_key_commitment(&header, &key)?;
let aead = build_aead(&key);
let chunk_sz_usize = policy::validate_chunk_size(header.chunk_size)?;
let cipher_chunk_usize = policy::cipher_chunk_len(chunk_sz_usize)?;
let chunk_sz = chunk_sz_usize as u64;
let cipher_chunk = cipher_chunk_usize as u64;
// Layout invariants:
// n_chunks = ceil(total / chunk_sz), but always ≥ 1 (the empty file
// still authenticates a single empty "last" chunk).
// last_idx = n_chunks - 1
// last_pt = total - last_idx * chunk_sz (in [0, chunk_sz])
let (n_chunks, last_pt) = if total == 0 {
(1u64, 0u64)
} else {
let n = total.div_ceil(chunk_sz);
let before_last = policy::checked_mul_u64(n - 1, chunk_sz, "last chunk offset")?;
let last = total
.checked_sub(before_last)
.ok_or_else(|| FcryError::Format("last chunk length underflow".into()))?;
(n, last)
};
let last_idx = n_chunks - 1;
let mut out = OutSink::open_with_options(output_file, output_options)?;
let start_chunk = offset / chunk_sz;
let end_chunk = (end - 1) / chunk_sz;
// Reusable buffer sized to a full chunk + tag.
let mut buf = Zeroizing::new(Vec::with_capacity(cipher_chunk_usize));
let mut file = reader.into_inner();
for i in start_chunk..=end_chunk {
let i_u32 =
u32::try_from(i).map_err(|_| FcryError::Format("chunk index exceeds u32".into()))?;
let is_last = i == last_idx;
let cipher_len = if is_last {
last_pt + TAG_LEN as u64
} else {
cipher_chunk
};
let cipher_len_usz =
usize::try_from(cipher_len).map_err(|_| FcryError::Format("chunk too big".into()))?;
let chunk_offset = policy::checked_add_u64(
header_len,
policy::checked_mul_u64(i, cipher_chunk, "ciphertext chunk offset")?,
"ciphertext chunk offset",
)?;
file.seek(SeekFrom::Start(chunk_offset))?;
buf.clear();
buf.resize(cipher_len_usz, 0);
file.read_exact(&mut buf)?;
let nonce = make_nonce(&header.nonce_prefix, i_u32, is_last);
aead.decrypt_in_place(&nonce, &aad, &mut *buf)?;
// `buf` is now plaintext for this chunk. Compute the chunk's plaintext
// window in absolute bytes and intersect with the requested range.
let chunk_start = policy::checked_mul_u64(i, chunk_sz, "plaintext chunk offset")?;
let chunk_end = policy::checked_count_add(chunk_start, buf.len(), "plaintext chunk end")?;
let lo = offset.max(chunk_start) - chunk_start;
let hi = end.min(chunk_end) - chunk_start;
out.write_all(&buf[lo as usize..hi as usize])?;
}
out.commit()?;
Ok(())
}
#[cfg(test)]
mod tests {
//! Regression tests for cross-version compatibility. The on-disk header
//! is part of the AEAD AAD, so any byte that ends up in `Header::encode()`
//! must match the bytes that were authenticated when the file was
//! written. The v1 test below catches the regression where `encode()`
//! used to hard-code the current version on output.
use super::*;
use crate::header::{Header, KdfParams, NONCE_PREFIX_LEN};
use std::fs;
use tempfile::TempDir;
fn write_v1_ciphertext(path: &std::path::Path, key: &SecretBytes32, plaintext: &[u8]) {
// Build a v1 header by hand: same wire format as v2 with flags=0,
// but with version byte = 1.
let nonce_prefix = [0x42u8; NONCE_PREFIX_LEN];
let header = Header {
version: 1,
alg: AlgId::XChaCha20Poly1305,
flags: 0,
chunk_size: 64,
kdf: KdfParams::Raw,
nonce_prefix,
plaintext_length: None,
key_commitment: None,
};
let aad = header.encode();
// First byte after MAGIC is the version — verify our fixture really
// is v1 (so this test fails open if encode() ever reverts).
assert_eq!(aad[4], 1);
let chunk_sz = header.chunk_size as usize;
let aead = build_aead(key);
let mut out = Vec::new();
out.extend_from_slice(&aad);
let mut counter: u32 = 0;
let mut pos = 0;
while pos < plaintext.len() {
let end = (pos + chunk_sz).min(plaintext.len());
let last = end == plaintext.len() && (end - pos) < chunk_sz;
let mut buf = plaintext[pos..end].to_vec();
let nonce = make_nonce(&nonce_prefix, counter, last);
aead.encrypt_in_place(&nonce, &aad, &mut buf).unwrap();
out.extend_from_slice(&buf);
pos = end;
if last {
break;
}
// If we hit a chunk-boundary EOF we still need a trailing "last"
// empty chunk to authenticate end-of-stream.
counter = bump_counter(counter).unwrap();
if pos == plaintext.len() {
let mut empty = Vec::new();
let nonce = make_nonce(&nonce_prefix, counter, true);
aead.encrypt_in_place(&nonce, &aad, &mut empty).unwrap();
out.extend_from_slice(&empty);
break;
}
}
// Empty plaintext: emit a single empty "last" chunk.
if plaintext.is_empty() {
let mut empty = Vec::new();
let nonce = make_nonce(&nonce_prefix, 0, true);
aead.encrypt_in_place(&nonce, &aad, &mut empty).unwrap();
out.extend_from_slice(&empty);
}
fs::write(path, &out).unwrap();
}
#[test]
fn decrypts_v1_ciphertext() {
let dir = TempDir::new().unwrap();
let ct = dir.path().join("v1.bin");
let rt = dir.path().join("rt.bin");
let mut key = SecretBytes32::zeroed();
key.with_mut_array(|k| k.copy_from_slice(b"0123456789abcdef0123456789abcdef"));
// Multi-chunk plaintext (chunk_size = 64 in the fixture).
let plain: Vec<u8> = (0..200u8).collect();
write_v1_ciphertext(&ct, &key, &plain);
decrypt(
Some(ct.to_str().unwrap()),
Some(rt.to_str().unwrap()),
Some(&key),
None,
1,
)
.expect("v1 decrypt should succeed");
let got = fs::read(&rt).unwrap();
assert_eq!(got, plain);
}
#[test]
fn decrypts_v1_ciphertext_parallel() {
// Same fixture, but exercising the multi-threaded pipeline.
let dir = TempDir::new().unwrap();
let ct = dir.path().join("v1.bin");
let rt = dir.path().join("rt.bin");
let mut key = SecretBytes32::zeroed();
key.with_mut_array(|k| k.copy_from_slice(b"0123456789abcdef0123456789abcdef"));
let plain: Vec<u8> = (0..200u8).collect();
write_v1_ciphertext(&ct, &key, &plain);
decrypt(
Some(ct.to_str().unwrap()),
Some(rt.to_str().unwrap()),
Some(&key),
None,
4,
)
.expect("v1 parallel decrypt should succeed");
assert_eq!(fs::read(&rt).unwrap(), plain);
}
}
src/error.rs
+2 -1
View File
@@ -1,4 +1,4 @@
// SPDX-License-Identifier: GPL-3.0-only
// SPDX-License-Identifier: MIT-0
use chacha20poly1305::aead;
use std::io;
@@ -12,6 +12,7 @@ pub enum FcryError {
Format(String),
Kdf(String),
Passphrase(String),
WrongKey,
}
impl From<io::Error> for FcryError {
src/header.rs
+205 -12
View File
@@ -1,4 +1,4 @@
// SPDX-License-Identifier: GPL-3.0-only
// SPDX-License-Identifier: MIT-0
//! On-disk file format for fcry.
//!
@@ -13,25 +13,46 @@
//! kdf_id u8 1
//! kdf_params variable (depends on kdf_id)
//! nonce_prefix [u8; 19] 19 (STREAM nonce prefix)
//! plaintext_length u64 LE 8 (only if version >= 2 and flags & 0x01)
//! key_commitment [u8; 32] 32 (only if version >= 3 and flags & 0x02)
//! --- end of header ---
//! chunk[0..N] each chunk_size + 16 bytes,
//! last may be shorter
//! ```
//!
//! The full encoded header is fed as AAD to every chunk, so any tampering
//! with chunk_size, nonce_prefix, kdf params, etc. causes authentication
//! failure on every chunk.
//! with chunk_size, nonce_prefix, kdf params, plaintext_length, etc. causes
//! authentication failure on every chunk.
//!
//! Versions:
//! * v1 — no length committed, no flag bits used.
//! * v2 — adds `FLAG_LENGTH_COMMITTED` (bit 0); when set, the total plaintext
//! length is appended after `nonce_prefix`. This enables random-access
//! decryption without scanning predecessors.
//! * v3 — adds `FLAG_KEY_COMMITTED` (bit 1) and an authenticated key
//! commitment for fast wrong-key detection before chunk processing.
use std::io::Read;
use crate::error::FcryError;
use crate::policy;
const MAGIC: [u8; 4] = *b"fcry";
const VERSION: u8 = 1;
pub const VERSION_CURRENT: u8 = 3;
const VERSION_MIN: u8 = 1;
pub const NONCE_PREFIX_LEN: usize = 19;
pub const TAG_LEN: usize = 16;
/// Set in `flags` when the header carries an authenticated `plaintext_length`
/// field. Required for random-access decryption.
pub const FLAG_LENGTH_COMMITTED: u8 = 0x01;
pub const FLAG_KEY_COMMITTED: u8 = 0x02;
/// Mask of all flag bits this build understands. Unknown bits → reject.
const FLAG_KNOWN_MASK: u8 = FLAG_LENGTH_COMMITTED | FLAG_KEY_COMMITTED;
pub const KEY_COMMITMENT_LEN: usize = 32;
#[repr(u8)]
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum AlgId {
@@ -116,18 +137,26 @@ impl KdfParams {
#[derive(Clone, Debug)]
pub struct Header {
/// On-disk format version. Set to `VERSION_CURRENT` for new encrypts;
/// preserved as-read for decrypt so the AAD recomputed on decode matches
/// the bytes that were authenticated when the file was written.
pub version: u8,
pub alg: AlgId,
pub flags: u8,
pub chunk_size: u32,
pub kdf: KdfParams,
pub nonce_prefix: [u8; NONCE_PREFIX_LEN],
/// Total plaintext byte count. `Some` iff `flags & FLAG_LENGTH_COMMITTED`.
pub plaintext_length: Option<u64>,
/// v3 key commitment. `Some` iff `flags & FLAG_KEY_COMMITTED`.
pub key_commitment: Option<[u8; KEY_COMMITMENT_LEN]>,
}
impl Header {
pub fn encode(&self) -> Vec<u8> {
let mut out = Vec::with_capacity(64);
fn encode_without_commitment(&self) -> Vec<u8> {
let mut out = Vec::with_capacity(104);
out.extend_from_slice(&MAGIC);
out.push(VERSION);
out.push(self.version);
out.push(self.alg as u8);
out.push(self.flags);
out.push(0); // reserved
@@ -135,10 +164,39 @@ impl Header {
out.push(self.kdf.id());
self.kdf.write_into(&mut out);
out.extend_from_slice(&self.nonce_prefix);
if (self.flags & FLAG_LENGTH_COMMITTED) != 0 {
let len = self
.plaintext_length
.expect("FLAG_LENGTH_COMMITTED set but plaintext_length is None");
out.extend_from_slice(&len.to_le_bytes());
}
out
}
pub fn encode(&self) -> Vec<u8> {
let mut out = self.encode_without_commitment();
if (self.flags & FLAG_KEY_COMMITTED) != 0 {
let commitment = self
.key_commitment
.expect("FLAG_KEY_COMMITTED set but key_commitment is None");
out.extend_from_slice(&commitment);
}
out
}
pub fn commitment_input_encoding(&self) -> Vec<u8> {
self.encode_without_commitment()
}
#[allow(dead_code)]
pub fn read(r: &mut impl Read) -> Result<Self, FcryError> {
Self::read_with_argon_cap(r, policy::default_argon_decrypt_cap_mib())
}
pub fn read_with_argon_cap(
r: &mut impl Read,
max_argon_memory_mib: u32,
) -> Result<Self, FcryError> {
let mut magic = [0u8; 4];
r.read_exact(&mut magic)?;
if magic != MAGIC {
@@ -148,34 +206,68 @@ impl Header {
let mut fixed = [0u8; 4];
r.read_exact(&mut fixed)?;
let [version, alg_id, flags, reserved] = fixed;
if version != VERSION {
if !(VERSION_MIN..=VERSION_CURRENT).contains(&version) {
return Err(FcryError::Format(format!("unsupported version: {version}")));
}
if reserved != 0 {
return Err(FcryError::Format("reserved byte must be zero".into()));
}
if (flags & !FLAG_KNOWN_MASK) != 0 {
return Err(FcryError::Format(format!(
"unknown flag bits: 0x{flags:02x}"
)));
}
if version < 2 && flags != 0 {
return Err(FcryError::Format("v1 header must have flags == 0".into()));
}
if version < 3 && (flags & FLAG_KEY_COMMITTED) != 0 {
return Err(FcryError::Format(
"key commitment flag requires v3 header".into(),
));
}
if version >= 3 && (flags & FLAG_KEY_COMMITTED) == 0 {
return Err(FcryError::Format("v3 header must commit the key".into()));
}
let alg = AlgId::from_u8(alg_id)?;
let mut chunk_size_bytes = [0u8; 4];
r.read_exact(&mut chunk_size_bytes)?;
let chunk_size = u32::from_le_bytes(chunk_size_bytes);
if chunk_size == 0 {
return Err(FcryError::Format("chunk_size must be > 0".into()));
}
policy::validate_chunk_size(chunk_size)?;
let mut kdf_id = [0u8; 1];
r.read_exact(&mut kdf_id)?;
let kdf = KdfParams::read_from(kdf_id[0], r)?;
policy::validate_header_kdf(&kdf, max_argon_memory_mib)?;
let mut nonce_prefix = [0u8; NONCE_PREFIX_LEN];
r.read_exact(&mut nonce_prefix)?;
let plaintext_length = if (flags & FLAG_LENGTH_COMMITTED) != 0 {
let mut b = [0u8; 8];
r.read_exact(&mut b)?;
Some(u64::from_le_bytes(b))
} else {
None
};
let key_commitment = if (flags & FLAG_KEY_COMMITTED) != 0 {
let mut b = [0u8; KEY_COMMITMENT_LEN];
r.read_exact(&mut b)?;
Some(b)
} else {
None
};
Ok(Self {
version,
alg,
flags,
chunk_size,
kdf,
nonce_prefix,
plaintext_length,
key_commitment,
})
}
}
@@ -188,30 +280,87 @@ mod tests {
#[test]
fn roundtrip() {
let h = Header {
version: VERSION_CURRENT,
alg: AlgId::XChaCha20Poly1305,
flags: 0,
flags: FLAG_KEY_COMMITTED,
chunk_size: 1024 * 1024,
kdf: KdfParams::Raw,
nonce_prefix: [7u8; NONCE_PREFIX_LEN],
plaintext_length: None,
key_commitment: Some([1u8; KEY_COMMITMENT_LEN]),
};
let bytes = h.encode();
let mut cur = Cursor::new(&bytes);
let parsed = Header::read(&mut cur).unwrap();
assert_eq!(parsed.version, h.version);
assert_eq!(parsed.alg, h.alg);
assert_eq!(parsed.flags, h.flags);
assert_eq!(parsed.chunk_size, h.chunk_size);
assert_eq!(parsed.nonce_prefix, h.nonce_prefix);
assert_eq!(parsed.plaintext_length, None);
assert_eq!(parsed.key_commitment, h.key_commitment);
assert_eq!(cur.position() as usize, bytes.len());
}
#[test]
fn roundtrip_length_committed() {
let h = Header {
version: VERSION_CURRENT,
alg: AlgId::XChaCha20Poly1305,
flags: FLAG_LENGTH_COMMITTED | FLAG_KEY_COMMITTED,
chunk_size: 65536,
kdf: KdfParams::Raw,
nonce_prefix: [9u8; NONCE_PREFIX_LEN],
plaintext_length: Some(123_456_789),
key_commitment: Some([2u8; KEY_COMMITMENT_LEN]),
};
let bytes = h.encode();
let mut cur = Cursor::new(&bytes);
let parsed = Header::read(&mut cur).unwrap();
assert_eq!(parsed.flags, FLAG_LENGTH_COMMITTED | FLAG_KEY_COMMITTED);
assert_eq!(parsed.plaintext_length, Some(123_456_789));
assert_eq!(parsed.key_commitment, h.key_commitment);
assert_eq!(cur.position() as usize, bytes.len());
}
#[test]
fn v3_encoding_layout_stable() {
let h = Header {
version: VERSION_CURRENT,
alg: AlgId::XChaCha20Poly1305,
flags: FLAG_LENGTH_COMMITTED | FLAG_KEY_COMMITTED,
chunk_size: 0x0102_0304,
kdf: KdfParams::Raw,
nonce_prefix: [0x55u8; NONCE_PREFIX_LEN],
plaintext_length: Some(0x0807_0605_0403_0201),
key_commitment: Some([0xaau8; KEY_COMMITMENT_LEN]),
};
let commitment_input = h.commitment_input_encoding();
assert_eq!(commitment_input.len(), 40);
assert_eq!(&commitment_input[..4], b"fcry");
assert_eq!(commitment_input[4], 3);
assert_eq!(
&commitment_input[32..40],
&0x0807_0605_0403_0201u64.to_le_bytes()
);
let aad = h.encode();
assert_eq!(aad.len(), 72);
assert_eq!(&aad[..40], &commitment_input);
assert_eq!(&aad[40..], &[0xaau8; KEY_COMMITMENT_LEN]);
}
#[test]
fn rejects_bad_magic() {
let mut bytes = Header {
version: VERSION_CURRENT,
alg: AlgId::XChaCha20Poly1305,
flags: 0,
chunk_size: 4096,
kdf: KdfParams::Raw,
nonce_prefix: [0u8; NONCE_PREFIX_LEN],
plaintext_length: None,
key_commitment: Some([3u8; KEY_COMMITMENT_LEN]),
}
.encode();
bytes[0] ^= 1;
@@ -220,4 +369,48 @@ mod tests {
Err(FcryError::Format(_))
));
}
#[test]
fn rejects_unknown_flag_bits() {
let mut bytes = Header {
version: VERSION_CURRENT,
alg: AlgId::XChaCha20Poly1305,
flags: 0,
chunk_size: 4096,
kdf: KdfParams::Raw,
nonce_prefix: [0u8; NONCE_PREFIX_LEN],
plaintext_length: None,
key_commitment: Some([4u8; KEY_COMMITMENT_LEN]),
}
.encode();
// flags byte is at offset 6 (4 magic + version + alg)
bytes[6] = 0x80;
assert!(matches!(
Header::read(&mut Cursor::new(&bytes)),
Err(FcryError::Format(_))
));
}
#[test]
fn reads_v1_header() {
// hand-crafted v1 header (raw kdf, no length field)
let mut bytes = Vec::new();
bytes.extend_from_slice(b"fcry");
bytes.push(1); // version
bytes.push(1); // alg
bytes.push(0); // flags
bytes.push(0); // reserved
bytes.extend_from_slice(&1024u32.to_le_bytes());
bytes.push(0); // kdf id raw
bytes.extend_from_slice(&[3u8; NONCE_PREFIX_LEN]);
let parsed = Header::read(&mut Cursor::new(&bytes)).unwrap();
assert_eq!(parsed.version, 1);
assert_eq!(parsed.flags, 0);
assert_eq!(parsed.chunk_size, 1024);
assert_eq!(parsed.plaintext_length, None);
assert_eq!(parsed.key_commitment, None);
// Re-encoding must reproduce the original v1 bytes exactly so the
// recomputed AAD matches what the file was authenticated with.
assert_eq!(parsed.encode(), bytes);
}
}
src/main.rs
+226 -33
View File
@@ -1,8 +1,10 @@
// SPDX-License-Identifier: GPL-3.0-only
// SPDX-License-Identifier: MIT-0
mod crypto;
mod error;
mod header;
mod pipeline;
mod policy;
mod reader;
mod secrets;
mod utils;
@@ -11,9 +13,13 @@ use crypto::*;
use error::FcryError;
use header::{ARGON2_SALT_LEN, KdfParams};
use secrets::{SecretBytes32, SecretVec, read_passphrase_tty};
use utils::DEFAULT_CHUNK_SIZE;
use utils::{DEFAULT_CHUNK_SIZE, OutSinkOptions};
use clap::Parser;
use std::fs::File;
use std::io::Read;
use std::path::{Path, PathBuf};
use unicode_normalization::UnicodeNormalization;
use zeroize::Zeroizing;
/// fcry - [f]ile[cry]pt: A file en-/decryption tool for easy use
@@ -33,10 +39,9 @@ struct Cli {
#[clap(short, long)]
output_file: Option<String>,
/// The raw bytes of the crypto key. Has to be exactly 32 bytes.
/// *** DANGEROUS: visible in process listings (ps/proc). Testing only. ***
#[clap(short, long, conflicts_with_all = ["passphrase", "passphrase_env"])]
raw_key: Option<Zeroizing<String>>,
/// Read the raw 32-byte crypto key from a file.
#[clap(short = 'k', long, conflicts_with_all = ["passphrase", "passphrase_env"])]
key_file: Option<PathBuf>,
/// Read passphrase interactively (terminal). Implies argon2id KDF on encrypt.
#[clap(short, long)]
@@ -52,37 +57,135 @@ struct Cli {
chunk_size: u32,
/// Argon2id memory in MiB (encryption only). Default: 1024 (= 1 GiB).
#[clap(long, default_value_t = 1024)]
#[clap(long, default_value_t = policy::DEFAULT_ARGON_MEMORY_MIB)]
argon_memory: u32,
/// Argon2id passes / iterations (encryption only).
#[clap(long, default_value_t = 2)]
#[clap(long, default_value_t = policy::MIN_ARGON_PASSES)]
argon_passes: u32,
/// Argon2id parallelism / lanes (encryption only).
#[clap(long, default_value_t = 4)]
#[clap(long, default_value_t = policy::DEFAULT_ARGON_PARALLELISM)]
argon_parallelism: u32,
/// Permit intentionally weak passphrase/KDF parameters for tests or legacy interop.
#[clap(long)]
allow_weak_kdf: bool,
/// Maximum Argon2id memory accepted while decrypting, in MiB.
/// Overrides the dynamic default. Raising it can OOM constrained machines.
#[clap(long)]
max_argon_memory_mib: Option<u32>,
/// Number of worker threads for AEAD work. Defaults to the number of
/// available CPUs. Set to 1 for fully serial encrypt/decrypt.
#[clap(short = 'j', long, value_parser = clap::value_parser!(u32).range(1..))]
threads: Option<u32>,
/// Replace an existing different output file after encryption/decryption succeeds.
#[clap(long)]
force: bool,
/// Directory for private temporary files.
#[clap(long)]
temp_dir: Option<PathBuf>,
/// For decrypt-to-stdout, verify the whole plaintext in a private temp file before emitting it.
#[clap(long, requires = "decrypt")]
buffer_verify: bool,
/// Random-access decrypt: byte offset of the slice to read.
/// Requires `--decrypt`, an `--input-file` whose header has the
/// length-committed flag set, and `--length`.
#[clap(
long,
requires = "length",
requires = "decrypt",
requires = "input_file"
)]
offset: Option<u64>,
/// Random-access decrypt: byte length of the slice to read.
/// Requires `--decrypt`, `--input-file`, and `--offset`.
#[clap(
long,
requires = "offset",
requires = "decrypt",
requires = "input_file"
)]
length: Option<u64>,
}
fn parse_raw_key(s: &str) -> Result<SecretBytes32, FcryError> {
let raw = s.as_bytes();
if raw.len() != 32 {
fn read_key_file(path: &Path) -> Result<SecretBytes32, FcryError> {
warn_if_key_file_world_readable(path);
let mut file = File::open(path)?;
let mut buf = Zeroizing::new([0u8; 33]);
let mut n = 0usize;
while n < buf.len() {
match file.read(&mut buf[n..]) {
Ok(0) => break,
Ok(read) => n += read,
Err(e) if e.kind() == std::io::ErrorKind::Interrupted => continue,
Err(e) => return Err(e.into()),
}
}
if n < 32 {
return Err(FcryError::Format(format!(
"raw_key must be exactly 32 bytes, got {}",
raw.len()
"key file {} is too short: expected exactly 32 bytes, got {n}",
path.display()
)));
}
if n > 32 {
return Err(FcryError::Format(format!(
"key file {} is too long: expected exactly 32 bytes; possible trailing newline",
path.display()
)));
}
let mut extra = Zeroizing::new([0u8; 1]);
if file.read(&mut *extra)? != 0 {
return Err(FcryError::Format(format!(
"key file {} is too long: expected exactly 32 bytes; possible trailing newline",
path.display()
)));
}
let mut key = SecretBytes32::zeroed();
key.with_mut_array(|key| key.copy_from_slice(raw));
key.with_mut_array(|key| key.copy_from_slice(&buf[..32]));
Ok(key)
}
#[cfg(unix)]
fn warn_if_key_file_world_readable(path: &Path) {
use std::os::unix::fs::PermissionsExt;
if let Ok(meta) = std::fs::metadata(path) {
let mode = meta.permissions().mode();
if (mode & 0o077) != 0 {
eprintln!(
"Warning: key file {} is group/world accessible; consider chmod 600",
path.display()
);
}
}
}
#[cfg(not(unix))]
fn warn_if_key_file_world_readable(_path: &Path) {}
/// Source of a passphrase: either the terminal or a named env var.
enum PassphraseSource {
Tty,
EnvVar(String),
}
fn normalize_passphrase(pw: SecretVec) -> Result<SecretVec, FcryError> {
let normalized = pw.with_slice(|bytes| {
let s = std::str::from_utf8(bytes).map_err(|_| {
FcryError::Passphrase("passphrase must be valid UTF-8 after normalization".into())
})?;
Ok::<Zeroizing<String>, FcryError>(Zeroizing::new(s.nfc().collect::<String>()))
})?;
Ok(SecretVec::from_vec(normalized.as_bytes().to_vec()))
}
fn read_passphrase(src: &PassphraseSource, confirm: bool) -> Result<SecretVec, FcryError> {
match src {
PassphraseSource::EnvVar(var) => {
@@ -90,17 +193,22 @@ fn read_passphrase(src: &PassphraseSource, confirm: bool) -> Result<SecretVec, F
// protected storage. The source Vec is zeroed after the copy.
// Note: a copy still exists in the process `environ` table; that is
// a known and accepted leak for the env-var path.
let v = std::env::var(var).map_err(|_| {
let v = Zeroizing::new(std::env::var(var).map_err(|_| {
FcryError::Passphrase(format!("environment variable {var} not set or not unicode"))
})?;
Ok(SecretVec::from_vec(v.into_bytes()))
})?);
let normalized = Zeroizing::new(v.as_str().nfc().collect::<String>());
Ok(SecretVec::from_vec(normalized.as_bytes().to_vec()))
}
PassphraseSource::Tty => {
let pw = read_passphrase_tty("Passphrase: ")
.map_err(|e| FcryError::Passphrase(e.to_string()))?;
let pw = normalize_passphrase(
read_passphrase_tty("Passphrase: ")
.map_err(|e| FcryError::Passphrase(e.to_string()))?,
)?;
if confirm {
let pw2 = read_passphrase_tty("Confirm passphrase: ")
.map_err(|e| FcryError::Passphrase(e.to_string()))?;
let pw2 = normalize_passphrase(
read_passphrase_tty("Confirm passphrase: ")
.map_err(|e| FcryError::Passphrase(e.to_string()))?,
)?;
if pw != pw2 {
return Err(FcryError::Passphrase("passphrases do not match".into()));
}
@@ -128,7 +236,7 @@ fn disable_core_dumps() {
fn run(mut cli: Cli) -> Result<(), FcryError> {
// Move the secret-bearing fields out of `Cli` immediately so they don't
// sit in the parsed struct for the rest of the function.
let raw_key_str: Option<Zeroizing<String>> = cli.raw_key.take();
let key_file: Option<PathBuf> = cli.key_file.take();
let pw_src: Option<PassphraseSource> = if cli.passphrase {
Some(PassphraseSource::Tty)
} else {
@@ -142,31 +250,107 @@ fn run(mut cli: Cli) -> Result<(), FcryError> {
let argon_memory = cli.argon_memory;
let argon_passes = cli.argon_passes;
let argon_parallelism = cli.argon_parallelism;
let allow_weak_kdf = cli.allow_weak_kdf;
let argon_cap = policy::resolve_argon_decrypt_cap(cli.max_argon_memory_mib)?;
if argon_cap.overridden && argon_cap.effective_mib > argon_cap.default_mib {
eprintln!(
"Warning: --max-argon-memory-mib raises the Argon2 decrypt trust ceiling from {} MiB to {} MiB; this can OOM constrained machines",
argon_cap.default_mib, argon_cap.effective_mib
);
}
let (threads, thread_warning) = policy::normalize_worker_threads(cli.threads);
if let Some(requested) = thread_warning {
eprintln!(
"Warning: requested {requested} worker threads; capped at {}",
policy::MAX_WORKER_THREADS
);
}
let force = cli.force;
let temp_dir = cli.temp_dir.take();
let buffer_verify = cli.buffer_verify;
let offset = cli.offset;
let length = cli.length;
drop(cli);
if pw_src.is_none() && raw_key_str.is_none() {
if pw_src.is_none() && key_file.is_none() {
return Err(FcryError::Format(
"must provide one of --raw-key, --passphrase, --passphrase-env".into(),
"must provide one of --key-file, --passphrase, --passphrase-env".into(),
));
}
if buffer_verify && !decrypt_mode {
return Err(FcryError::Format(
"--buffer-verify is only valid for decrypt".into(),
));
}
if buffer_verify && output.is_some() {
return Err(FcryError::Format(
"--buffer-verify is only meaningful when decrypting to stdout".into(),
));
}
let output_options = OutSinkOptions {
force,
input_file: input.as_ref().map(PathBuf::from),
temp_dir,
buffer_verify_stdout: buffer_verify,
};
if decrypt_mode {
let raw_key = match raw_key_str.as_deref() {
Some(s) => Some(parse_raw_key(s)?),
let raw_key = match key_file.as_deref() {
Some(path) => Some(read_key_file(path)?),
None => None,
};
let pw = match &pw_src {
Some(src) => Some(read_passphrase(src, false)?),
None => None,
};
decrypt(input, output, raw_key.as_ref(), pw.as_ref())?;
match (offset, length) {
(Some(o), Some(l)) => {
// clap's `requires` makes this unreachable, but keep the
// dynamic check so the failure mode is a clean error.
let path = input.as_deref().ok_or_else(|| {
FcryError::Format(
"--offset/--length require --input-file (random-access needs a seekable file)".into(),
)
})?;
decrypt_range_with_output_options(
path,
output,
raw_key.as_ref(),
pw.as_ref(),
o,
l,
argon_cap.effective_mib,
&output_options,
)?;
}
(None, None) => {
decrypt_with_output_options(
input,
output,
raw_key.as_ref(),
pw.as_ref(),
threads,
argon_cap.effective_mib,
&output_options,
)?;
}
_ => {
return Err(FcryError::Format(
"--offset and --length must be supplied together".into(),
));
}
}
} else {
let (key, kdf) = if let Some(src) = &pw_src {
let mut salt = [0u8; ARGON2_SALT_LEN];
getrandom::fill(&mut salt)?;
let m_cost_kib = argon_memory.checked_mul(1024).ok_or_else(|| {
FcryError::Format("argon-memory too large (overflow when converting to KiB)".into())
})?;
let m_cost_kib = policy::validate_new_argon_params(
argon_memory,
argon_passes,
argon_parallelism,
allow_weak_kdf,
)?;
let kdf = KdfParams::Argon2id {
salt,
m_cost: m_cost_kib,
@@ -174,13 +358,22 @@ fn run(mut cli: Cli) -> Result<(), FcryError> {
p_cost: argon_parallelism,
};
let pw = read_passphrase(src, true)?;
policy::validate_new_passphrase(&pw, allow_weak_kdf)?;
let key = derive_key(&kdf, None, Some(&pw))?;
(key, kdf)
} else {
let key = parse_raw_key(raw_key_str.as_deref().unwrap())?;
let key = read_key_file(key_file.as_deref().unwrap())?;
(key, KdfParams::Raw)
};
encrypt(input, output, &key, chunk_size, kdf)?;
encrypt_with_output_options(
input,
output,
&key,
chunk_size,
kdf,
threads,
&output_options,
)?;
}
Ok(())
src/pipeline.rs
+375
View File
@@ -0,0 +1,375 @@
// SPDX-License-Identifier: MIT-0
//! Multi-threaded encrypt/decrypt pipeline.
//!
//! Topology:
//!
//! ```text
//! reader thread → jobs (bounded MPMC) → N AEAD workers →
//! → results (bounded MPMC) → writer thread
//! ```
//!
//! The reader is sequential (one input handle, lookahead detects last chunk),
//! workers parallelize the AEAD step (independent per chunk), and the writer
//! reorders results by counter before writing them to `OutSink`.
//!
//! Bounded memory: a permit channel caps the total number of in-flight chunks
//! (queued jobs + in-progress at workers + pending in the writer's reorder
//! buffer). The reader acquires a permit before sending each job; the writer
//! releases a permit after flushing the chunk in order. A slow or stuck worker
//! therefore stalls the reader rather than letting the writer's reorder buffer
//! grow without bound.
//!
//! Fail-fast: a shared `cancel` flag lets workers signal an authentication or
//! AEAD error to the reader. The reader checks it each iteration and exits
//! early, so a tampered chunk doesn't waste full-file I/O on top of the
//! detection.
//!
//! Peak memory ≈ chunk_size × (in_flight_cap + 2). For 1 MiB chunks and 8
//! cores (cap = 32) that's ~34 MiB. Adjust `in_flight_capacity` if you need
//! a different memory/throughput tradeoff.
use std::collections::BTreeMap;
use std::io::Write;
use std::sync::Arc;
use std::sync::atomic::{AtomicBool, Ordering};
use std::thread::{self, JoinHandle};
use std::time::Duration;
use chacha20poly1305::{XChaCha20Poly1305, aead::AeadInPlace};
use crossbeam_channel::{Receiver, RecvTimeoutError, Sender, bounded};
use crate::crypto::{bump_counter, make_nonce};
use crate::error::FcryError;
use crate::header::NONCE_PREFIX_LEN;
use crate::policy;
use crate::reader::{AheadReader, ReadInfoChunk};
use crate::utils::OutSink;
use zeroize::Zeroizing;
struct Job {
counter: u32,
last: bool,
buf: Zeroizing<Vec<u8>>,
}
struct Done {
counter: u32,
buf: Zeroizing<Vec<u8>>,
}
/// Job-channel capacity: small multiples of worker count, enough to keep
/// workers fed without unbounded memory.
fn channel_capacity(threads: usize, in_flight: usize) -> usize {
policy::pipeline_channel_capacity(threads, in_flight)
}
/// Total in-flight chunk cap (jobs queued + at workers + in writer's reorder
/// buffer). Permit count; bounded above the job-channel capacity to absorb
/// reordering without blocking workers unnecessarily.
fn in_flight_capacity(threads: usize, chunk_len: usize) -> usize {
policy::pipeline_in_flight_capacity(threads, chunk_len)
}
#[allow(clippy::too_many_arguments)]
pub(crate) fn encrypt_parallel(
input: AheadReader,
output: OutSink,
aead: Arc<XChaCha20Poly1305>,
aad: Arc<Vec<u8>>,
nonce_prefix: [u8; NONCE_PREFIX_LEN],
chunk_sz: usize,
threads: usize,
expected_length: Option<u64>,
) -> Result<(), FcryError> {
let (sink, bytes_seen) = run_pipeline(
input,
output,
aead,
aad,
nonce_prefix,
chunk_sz,
threads,
true,
)?;
if let Some(committed) = expected_length
&& committed != bytes_seen
{
return Err(FcryError::Format(format!(
"input length changed during encryption: committed {committed}, read {bytes_seen}"
)));
}
sink.commit()?;
Ok(())
}
#[allow(clippy::too_many_arguments)]
pub(crate) fn decrypt_parallel(
input: AheadReader,
output: OutSink,
aead: Arc<XChaCha20Poly1305>,
aad: Arc<Vec<u8>>,
nonce_prefix: [u8; NONCE_PREFIX_LEN],
cipher_chunk: usize,
threads: usize,
expected_length: Option<u64>,
) -> Result<(), FcryError> {
let (sink, written) = run_pipeline(
input,
output,
aead,
aad,
nonce_prefix,
cipher_chunk,
threads,
false,
)?;
if let Some(committed) = expected_length
&& committed != written
{
return Err(FcryError::Format(format!(
"decrypted length {written} disagrees with committed {committed}"
)));
}
sink.commit()?;
Ok(())
}
/// Drives the reader/worker/writer pipeline. `is_encrypt = true` performs
/// `encrypt_in_place` and tracks bytes-read; `false` performs
/// `decrypt_in_place` and tracks bytes-written. The single shared topology
/// keeps backpressure, reorder, and fail-fast logic in one place.
#[allow(clippy::too_many_arguments)]
fn run_pipeline(
mut input: AheadReader,
output: OutSink,
aead: Arc<XChaCha20Poly1305>,
aad: Arc<Vec<u8>>,
nonce_prefix: [u8; NONCE_PREFIX_LEN],
chunk_sz: usize,
threads: usize,
is_encrypt: bool,
) -> Result<(OutSink, u64), FcryError> {
let in_flight = in_flight_capacity(threads, chunk_sz);
let cap = channel_capacity(threads, in_flight);
let (jobs_tx, jobs_rx) = bounded::<Job>(cap);
let (done_tx, done_rx) = bounded::<Done>(cap);
// Pre-fill the permit channel. Each permit represents one in-flight chunk
// slot. The reader consumes a permit before sending a job; the writer
// returns a permit after flushing in order.
let (permit_tx, permit_rx) = bounded::<()>(in_flight);
for _ in 0..in_flight {
permit_tx
.send(())
.expect("pre-fill of permit channel cannot fail");
}
let cancel = Arc::new(AtomicBool::new(false));
// Reader thread: dispatches jobs in counter order and tracks bytes read
// (used for the encrypt-side length cross-check). On decrypt the count is
// ignored — the writer's count is authoritative there.
let reader_handle: JoinHandle<Result<u64, FcryError>> = {
let cancel = cancel.clone();
thread::spawn(move || {
let mut counter: u32 = 0;
let mut bytes_seen: u64 = 0;
loop {
// Acquire an in-flight slot. We recv with a short timeout so
// a worker error (which sets `cancel`) is observed even if
// the rest of the pipeline has quiesced and is no longer
// releasing permits — this avoids a 3-way deadlock between
// reader, idle workers, and a stalled writer.
loop {
if cancel.load(Ordering::Acquire) {
return Ok(bytes_seen);
}
match permit_rx.recv_timeout(Duration::from_millis(50)) {
Ok(()) => break,
Err(RecvTimeoutError::Timeout) => continue,
Err(RecvTimeoutError::Disconnected) => return Ok(bytes_seen),
}
}
let mut buf = Zeroizing::new(vec![0u8; chunk_sz]);
match input.read_ahead(&mut buf)? {
ReadInfoChunk::Normal(_) => {
if jobs_tx
.send(Job {
counter,
last: false,
buf,
})
.is_err()
{
return Ok(bytes_seen);
}
bytes_seen = policy::checked_count_add(bytes_seen, chunk_sz, "bytes read")?;
counter = bump_counter(counter)?;
}
ReadInfoChunk::Last(n) => {
buf.truncate(n);
let _ = jobs_tx.send(Job {
counter,
last: true,
buf,
});
bytes_seen = policy::checked_count_add(bytes_seen, n, "bytes read")?;
return Ok(bytes_seen);
}
ReadInfoChunk::Empty => {
if is_encrypt {
buf.clear();
let _ = jobs_tx.send(Job {
counter,
last: true,
buf,
});
return Ok(bytes_seen);
}
// On decrypt an unexpected EOF means the ciphertext is
// truncated. Surface it as an error so the writer
// doesn't commit a partial output.
return Err(FcryError::Format(
"truncated ciphertext: missing final chunk".into(),
));
}
}
}
})
};
// Worker threads: AEAD encrypt/decrypt in place, ship to writer. On error
// we set the cancel flag so the reader exits early, and drop the senders
// so the writer drains and exits.
let mut worker_handles: Vec<JoinHandle<Result<(), FcryError>>> = Vec::with_capacity(threads);
for _ in 0..threads {
let jobs_rx = jobs_rx.clone();
let done_tx = done_tx.clone();
let aead = aead.clone();
let aad = aad.clone();
let cancel = cancel.clone();
worker_handles.push(thread::spawn(move || {
for mut job in jobs_rx.iter() {
if cancel.load(Ordering::Acquire) {
// Drain remaining queued jobs without doing AEAD work.
// Returning Ok here keeps the previously-set error from
// being clobbered by a fresh "ok" status.
break;
}
let nonce = make_nonce(&nonce_prefix, job.counter, job.last);
let res = if is_encrypt {
aead.encrypt_in_place(&nonce, aad.as_slice(), &mut *job.buf)
} else {
aead.decrypt_in_place(&nonce, aad.as_slice(), &mut *job.buf)
};
if let Err(e) = res {
cancel.store(true, Ordering::Release);
return Err(e.into());
}
if done_tx
.send(Done {
counter: job.counter,
buf: job.buf,
})
.is_err()
{
break;
}
}
Ok(())
}));
}
drop(jobs_rx);
drop(done_tx);
// Writer thread: ordered writeback. Returns the `OutSink` ownership back
// without committing; the caller commits only after every other thread
// has joined cleanly so a failure anywhere drops the sink and unlinks the
// temp file. Releases one permit per chunk flushed so the reader can make
// forward progress in lockstep with the actual disk write.
let writer_handle: JoinHandle<Result<(OutSink, u64), FcryError>> =
thread::spawn(move || ordered_writer(done_rx, output, permit_tx));
let reader_res = reader_handle.join().expect("reader thread panicked");
let mut first_err: Option<FcryError> = None;
let bytes_seen = match reader_res {
Ok(n) => Some(n),
Err(e) => {
cancel.store(true, Ordering::Release);
first_err.get_or_insert(e);
None
}
};
for h in worker_handles {
if let Err(e) = h.join().expect("worker thread panicked")
&& first_err.is_none()
{
first_err = Some(e);
}
}
let writer_res = writer_handle.join().expect("writer thread panicked");
let written = match writer_res {
Ok((sink, n)) => Some((sink, n)),
Err(e) => {
if first_err.is_none() {
first_err = Some(e);
}
None
}
};
if let Some(e) = first_err {
return Err(e);
}
let (sink, n) = written.expect("no error but no sink");
let count = if is_encrypt {
bytes_seen.expect("no error but no reader count")
} else {
n
};
Ok((sink, count))
}
/// Drain `done_rx` in counter order, writing each chunk to `output` and
/// returning a permit to `permit_tx` after every flush so the reader is held
/// in lockstep with disk writes (bounded reorder buffer).
fn ordered_writer(
done_rx: Receiver<Done>,
mut output: OutSink,
permit_tx: Sender<()>,
) -> Result<(OutSink, u64), FcryError> {
let mut next: u32 = 0;
let mut pending: BTreeMap<u32, Zeroizing<Vec<u8>>> = BTreeMap::new();
let mut total: u64 = 0;
for done in done_rx.iter() {
pending.insert(done.counter, done.buf);
while let Some(buf) = pending.remove(&next) {
output.write_all(&buf)?;
total = policy::checked_count_add(total, buf.len(), "bytes written")?;
// `bump_counter` rejects overflow upstream; a wrap here would be
// a real bug, so use plain addition and let it panic in debug.
next += 1;
// Release one in-flight slot. If the reader is gone the channel
// is closed; we don't care about the send result.
let _ = permit_tx.send(());
}
}
if !pending.is_empty() {
return Err(FcryError::Format(
"internal: ordered writer left chunks unflushed".into(),
));
}
Ok((output, total))
}
// Compile-time check that the job type is Send+Sync (channel sends across
// threads). Kept as a footgun for future struct edits.
#[allow(dead_code)]
fn _assert_send_sync<T: Send + Sync>() {}
const _: fn() = || _assert_send_sync::<Sender<Job>>();
src/policy.rs
+299
View File
@@ -0,0 +1,299 @@
// SPDX-License-Identifier: MIT-0
//! Central resource and format policy.
use std::fs;
use crate::error::FcryError;
use crate::header::{KdfParams, TAG_LEN};
use crate::secrets::SecretVec;
pub const MAX_CHUNK_SIZE: u32 = 64 * 1024 * 1024;
pub const DEFAULT_CHUNK_SIZE: u32 = 1024 * 1024;
pub const DEFAULT_ARGON_MEMORY_MIB: u32 = 1024;
pub const MIN_ARGON_MEMORY_MIB: u32 = 64;
pub const DEFAULT_ARGON_DECRYPT_CAP_MIB: u32 = 4096;
pub const MIN_ARGON_PASSES: u32 = 2;
pub const MAX_ARGON_PASSES: u32 = 64;
pub const DEFAULT_ARGON_PARALLELISM: u32 = 4;
pub const MAX_ARGON_PARALLELISM: u32 = 64;
pub const MIN_PASSPHRASE_BYTES: usize = 12;
pub const MAX_WORKER_THREADS: usize = 256;
pub const PIPELINE_IN_FLIGHT_BYTES: usize = 128 * 1024 * 1024;
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub struct ArgonDecryptCap {
pub default_mib: u32,
pub effective_mib: u32,
pub overridden: bool,
}
pub fn architecture_argon_cap_mib() -> u32 {
let usize_cap_mib = usize::MAX / 1024 / 1024;
let argon_m_cost_cap_mib = (u32::MAX / 1024) as usize;
usize_cap_mib
.min(argon_m_cost_cap_mib)
.min(u32::MAX as usize) as u32
}
#[cfg(target_os = "linux")]
fn available_memory_mib() -> Option<u32> {
let meminfo = fs::read_to_string("/proc/meminfo").ok()?;
for line in meminfo.lines() {
let Some(rest) = line.strip_prefix("MemAvailable:") else {
continue;
};
let kib = rest.split_whitespace().next()?.parse::<u64>().ok()?;
return u32::try_from(kib / 1024).ok();
}
None
}
#[cfg(not(target_os = "linux"))]
fn available_memory_mib() -> Option<u32> {
None
}
pub fn default_argon_decrypt_cap_mib() -> u32 {
let mut cap = DEFAULT_ARGON_DECRYPT_CAP_MIB.min(architecture_argon_cap_mib());
if let Some(available) = available_memory_mib() {
cap = cap.min(available);
}
cap.max(1)
}
pub fn resolve_argon_decrypt_cap(override_mib: Option<u32>) -> Result<ArgonDecryptCap, FcryError> {
let default_mib = default_argon_decrypt_cap_mib();
let Some(effective_mib) = override_mib else {
return Ok(ArgonDecryptCap {
default_mib,
effective_mib: default_mib,
overridden: false,
});
};
if effective_mib == 0 {
return Err(FcryError::Format(
"--max-argon-memory-mib must be at least 1".into(),
));
}
let arch = architecture_argon_cap_mib();
if effective_mib > arch {
return Err(FcryError::Format(format!(
"--max-argon-memory-mib {effective_mib} exceeds this build's supported cap {arch}"
)));
}
Ok(ArgonDecryptCap {
default_mib,
effective_mib,
overridden: true,
})
}
pub fn mib_to_kib(mib: u32, name: &str) -> Result<u32, FcryError> {
mib.checked_mul(1024).ok_or_else(|| {
FcryError::Format(format!("{name} too large (overflow converting MiB to KiB)"))
})
}
pub fn validate_chunk_size(chunk_size: u32) -> Result<usize, FcryError> {
if chunk_size == 0 {
return Err(FcryError::Format("chunk_size must be > 0".into()));
}
if chunk_size > MAX_CHUNK_SIZE {
return Err(FcryError::Format(format!(
"chunk_size {chunk_size} exceeds maximum {MAX_CHUNK_SIZE}"
)));
}
usize::try_from(chunk_size)
.map_err(|_| FcryError::Format("chunk_size does not fit in usize".into()))
}
pub fn cipher_chunk_len(plain_chunk_len: usize) -> Result<usize, FcryError> {
plain_chunk_len
.checked_add(TAG_LEN)
.ok_or_else(|| FcryError::Format("cipher chunk length overflow".into()))
}
pub fn validate_new_argon_params(
memory_mib: u32,
passes: u32,
parallelism: u32,
allow_weak_kdf: bool,
) -> Result<u32, FcryError> {
if !allow_weak_kdf && memory_mib < MIN_ARGON_MEMORY_MIB {
return Err(FcryError::Kdf(format!(
"argon-memory must be at least {MIN_ARGON_MEMORY_MIB} MiB for new encryption (use --allow-weak-kdf only for tests/legacy interop)"
)));
}
if !allow_weak_kdf && passes < MIN_ARGON_PASSES {
return Err(FcryError::Kdf(format!(
"argon-passes must be at least {MIN_ARGON_PASSES} for new encryption (use --allow-weak-kdf only for tests/legacy interop)"
)));
}
validate_argon_common(memory_mib, passes, parallelism, "new encryption")?;
mib_to_kib(memory_mib, "argon-memory")
}
pub fn validate_new_passphrase(pw: &SecretVec, allow_weak_kdf: bool) -> Result<(), FcryError> {
let len = pw.len();
if len == 0 {
return Err(FcryError::Passphrase("passphrase must not be empty".into()));
}
if !allow_weak_kdf && len < MIN_PASSPHRASE_BYTES {
return Err(FcryError::Passphrase(format!(
"passphrase must be at least {MIN_PASSPHRASE_BYTES} UTF-8 bytes for new encryption (use --allow-weak-kdf only for tests/legacy interop)"
)));
}
Ok(())
}
pub fn validate_header_kdf(kdf: &KdfParams, max_argon_memory_mib: u32) -> Result<(), FcryError> {
match kdf {
KdfParams::Raw => Ok(()),
KdfParams::Argon2id {
m_cost,
t_cost,
p_cost,
..
} => {
let cap_kib = mib_to_kib(max_argon_memory_mib, "max argon memory")?;
if *m_cost == 0 {
return Err(FcryError::Format("argon2id memory cost must be > 0".into()));
}
if *t_cost == 0 {
return Err(FcryError::Format("argon2id passes must be > 0".into()));
}
if *p_cost == 0 {
return Err(FcryError::Format("argon2id parallelism must be > 0".into()));
}
if *m_cost > cap_kib {
return Err(FcryError::Kdf(format!(
"argon2id memory cost {} KiB exceeds configured decrypt cap {} MiB",
*m_cost, max_argon_memory_mib
)));
}
if *t_cost > MAX_ARGON_PASSES {
return Err(FcryError::Kdf(format!(
"argon2id passes {} exceeds maximum {}",
*t_cost, MAX_ARGON_PASSES
)));
}
if *p_cost > MAX_ARGON_PARALLELISM {
return Err(FcryError::Kdf(format!(
"argon2id parallelism {} exceeds maximum {}",
*p_cost, MAX_ARGON_PARALLELISM
)));
}
Ok(())
}
}
}
pub fn validate_argon_common(
memory_mib: u32,
passes: u32,
parallelism: u32,
context: &str,
) -> Result<(), FcryError> {
if memory_mib == 0 {
return Err(FcryError::Kdf(format!(
"argon-memory must be > 0 for {context}"
)));
}
if passes == 0 {
return Err(FcryError::Kdf(format!(
"argon-passes must be > 0 for {context}"
)));
}
if passes > MAX_ARGON_PASSES {
return Err(FcryError::Kdf(format!(
"argon-passes {passes} exceeds maximum {MAX_ARGON_PASSES}"
)));
}
if parallelism == 0 {
return Err(FcryError::Kdf(format!(
"argon-parallelism must be > 0 for {context}"
)));
}
if parallelism > MAX_ARGON_PARALLELISM {
return Err(FcryError::Kdf(format!(
"argon-parallelism {parallelism} exceeds maximum {MAX_ARGON_PARALLELISM}"
)));
}
if memory_mib > architecture_argon_cap_mib() {
return Err(FcryError::Kdf(format!(
"argon-memory {memory_mib} exceeds this build's supported cap {}",
architecture_argon_cap_mib()
)));
}
Ok(())
}
pub fn normalize_worker_threads(requested: Option<u32>) -> (usize, Option<u32>) {
let requested = requested.map(|n| n as usize).unwrap_or_else(|| {
std::thread::available_parallelism()
.map(|n| n.get())
.unwrap_or(1)
});
let capped = requested.clamp(1, MAX_WORKER_THREADS);
let warning = (requested > MAX_WORKER_THREADS).then_some(requested as u32);
(capped, warning)
}
pub fn pipeline_in_flight_capacity(threads: usize, chunk_len: usize) -> usize {
let chunk_len = chunk_len.max(1);
let thread_cap = threads.saturating_mul(4).max(1);
let byte_cap = (PIPELINE_IN_FLIGHT_BYTES / chunk_len).max(1);
thread_cap.min(byte_cap)
}
pub fn pipeline_channel_capacity(threads: usize, in_flight: usize) -> usize {
threads.saturating_mul(2).max(1).min(in_flight.max(1))
}
pub fn checked_add_u64(a: u64, b: u64, what: &str) -> Result<u64, FcryError> {
a.checked_add(b)
.ok_or_else(|| FcryError::Format(format!("{what} overflow")))
}
pub fn checked_mul_u64(a: u64, b: u64, what: &str) -> Result<u64, FcryError> {
a.checked_mul(b)
.ok_or_else(|| FcryError::Format(format!("{what} overflow")))
}
pub fn checked_count_add(total: u64, delta: usize, what: &str) -> Result<u64, FcryError> {
checked_add_u64(total, delta as u64, what)
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn chunk_size_bounds() {
assert!(validate_chunk_size(1).is_ok());
assert!(validate_chunk_size(MAX_CHUNK_SIZE).is_ok());
assert!(validate_chunk_size(0).is_err());
assert!(validate_chunk_size(MAX_CHUNK_SIZE + 1).is_err());
}
#[test]
fn argon_cap_override_replaces_default() {
let down = resolve_argon_decrypt_cap(Some(1)).unwrap();
assert_eq!(down.effective_mib, 1);
assert!(down.overridden);
let default = resolve_argon_decrypt_cap(None).unwrap();
assert_eq!(default.effective_mib, default.default_mib);
assert!(!default.overridden);
}
#[test]
fn pipeline_capacity_has_one_chunk_minimum() {
assert_eq!(
pipeline_in_flight_capacity(4, PIPELINE_IN_FLIGHT_BYTES * 2),
1
);
}
}
src/reader.rs
+8 -7
View File
@@ -1,7 +1,8 @@
// SPDX-License-Identifier: GPL-3.0-only
// SPDX-License-Identifier: MIT-0
use std::io;
use std::io::{BufRead, Read};
use zeroize::Zeroizing;
pub enum ReadInfoChunk {
Normal(#[allow(dead_code)] usize),
@@ -10,17 +11,17 @@ pub enum ReadInfoChunk {
}
pub struct AheadReader {
inner: Box<dyn BufRead>,
buf: Vec<u8>,
inner: Box<dyn BufRead + Send>,
buf: Zeroizing<Vec<u8>>,
bufsz: usize,
capacity: usize,
}
impl AheadReader {
pub fn from(reader: Box<dyn BufRead>, capacity: usize) -> Self {
pub fn from(reader: Box<dyn BufRead + Send>, capacity: usize) -> Self {
Self {
inner: reader,
buf: vec![0; capacity],
buf: Zeroizing::new(vec![0; capacity]),
bufsz: 0,
capacity,
}
@@ -61,7 +62,7 @@ impl AheadReader {
}
// 2nd read directly into our internal buf
let mut tmp = vec![0u8; self.capacity];
let mut tmp = Zeroizing::new(vec![0u8; self.capacity]);
let n2 = self.read_until_full(&mut tmp)?;
self.buf = tmp;
self.bufsz = n2;
@@ -78,7 +79,7 @@ impl AheadReader {
let userbuf_sz = self.bufsz;
// 2nd read directly into our internal buf
let mut tmp = vec![0u8; self.capacity];
let mut tmp = Zeroizing::new(vec![0u8; self.capacity]);
let n2 = self.read_until_full(&mut tmp)?;
self.buf = tmp;
self.bufsz = n2;
src/secrets.rs
+57 -15
View File
@@ -1,4 +1,4 @@
// SPDX-License-Identifier: GPL-3.0-only
// SPDX-License-Identifier: MIT-0
//! Secret-handling primitives.
//!
@@ -95,6 +95,10 @@ impl SecretVec {
let inner = self.inner.borrow();
f(&inner[..self.len])
}
pub fn len(&self) -> usize {
self.len
}
}
impl PartialEq for SecretVec {
@@ -192,13 +196,15 @@ mod imp {
mod imp {
use super::{MAX_PASSPHRASE_LEN, SecretVec};
use std::fs::OpenOptions;
use std::io::{self, Read, Write};
use std::io::{self, Write};
use std::os::windows::io::AsRawHandle;
use std::ptr;
use windows_sys::Win32::Foundation::HANDLE;
use windows_sys::Win32::System::Console::{
ENABLE_ECHO_INPUT, ENABLE_LINE_INPUT, ENABLE_PROCESSED_INPUT, GetConsoleMode,
ENABLE_ECHO_INPUT, ENABLE_LINE_INPUT, ENABLE_PROCESSED_INPUT, GetConsoleMode, ReadConsoleW,
SetConsoleMode,
};
use zeroize::Zeroizing;
struct ConsoleModeGuard {
handle: HANDLE,
@@ -214,7 +220,7 @@ mod imp {
}
pub fn read_passphrase_tty(prompt: &str) -> io::Result<SecretVec> {
let mut tty_in = OpenOptions::new().read(true).write(true).open("CONIN$")?;
let tty_in = OpenOptions::new().read(true).write(true).open("CONIN$")?;
let mut tty_out = OpenOptions::new().write(true).open("CONOUT$")?;
let h_in = tty_in.as_raw_handle() as HANDLE;
@@ -236,18 +242,38 @@ mod imp {
write!(tty_out, "{prompt}")?;
tty_out.flush()?;
let mut buf = SecretVec::with_capacity(MAX_PASSPHRASE_LEN);
let mut byte = [0u8; 1];
let mut wide = Zeroizing::new(Vec::<u16>::with_capacity(MAX_PASSPHRASE_LEN));
loop {
match tty_in.read(&mut byte) {
Ok(0) => break,
Ok(_) => match byte[0] {
b'\n' => break,
b'\r' => continue,
b => buf.push(b)?,
},
Err(e) if e.kind() == io::ErrorKind::Interrupted => continue,
Err(e) => return Err(e),
let mut unit = 0u16;
let mut read = 0u32;
let ok = unsafe {
ReadConsoleW(
h_in,
(&mut unit as *mut u16).cast(),
1,
&mut read,
ptr::null_mut(),
)
};
if ok == 0 {
return Err(io::Error::last_os_error());
}
if read == 0 {
break;
}
const LF: u16 = b'\n' as u16;
const CR: u16 = b'\r' as u16;
match unit {
LF | CR => break,
u => {
if wide.len() >= MAX_PASSPHRASE_LEN {
return Err(io::Error::new(
io::ErrorKind::InvalidInput,
"secret buffer full",
));
}
wide.push(u);
}
}
}
@@ -255,6 +281,22 @@ mod imp {
let _ = writeln!(tty_out);
let _ = tty_out.flush();
let utf8 = Zeroizing::new(String::from_utf16(&wide).map_err(|_| {
io::Error::new(
io::ErrorKind::InvalidData,
"console passphrase is not valid UTF-16",
)
})?);
if utf8.len() > MAX_PASSPHRASE_LEN {
return Err(io::Error::new(
io::ErrorKind::InvalidInput,
"secret buffer full",
));
}
let mut buf = SecretVec::with_capacity(MAX_PASSPHRASE_LEN);
for b in utf8.as_bytes() {
buf.push(*b)?;
}
Ok(buf)
}
}
src/utils.rs
+239 -64
View File
@@ -1,79 +1,271 @@
// SPDX-License-Identifier: GPL-3.0-only
// SPDX-License-Identifier: MIT-0
use std::fs::{self, File};
use std::io::{self, BufRead, BufReader, Write};
use std::path::PathBuf;
use std::fs::{self, File, OpenOptions};
use std::io::{self, BufRead, BufReader, Seek, SeekFrom, Write};
use std::path::{Path, PathBuf};
use crate::policy;
/// Default plaintext chunk size: 1 MiB.
///
/// Stored in the header per file, so callers may override via CLI without
/// breaking older files (the decryptor reads the size from the header).
pub const DEFAULT_CHUNK_SIZE: u32 = 1024 * 1024;
pub const DEFAULT_CHUNK_SIZE: u32 = policy::DEFAULT_CHUNK_SIZE;
pub(crate) fn open_input<S: AsRef<str>>(input_file: Option<S>) -> io::Result<Box<dyn BufRead>> {
Ok(match input_file {
Some(f) => Box::new(BufReader::new(File::open(f.as_ref())?)),
None => Box::new(io::stdin().lock()),
/// Opened input.
///
/// `length` is `Some(n)` only when the source is a regular file (we stat the
/// open FD to avoid TOCTOU). For stdin, FIFOs, sockets, char devices, etc.
/// it is `None` — those paths cannot commit a length in the header.
pub(crate) struct Input {
pub reader: Box<dyn BufRead + Send>,
pub length: Option<u64>,
}
pub(crate) fn open_input<S: AsRef<str>>(input_file: Option<S>) -> io::Result<Input> {
match input_file {
Some(f) => {
let file = File::open(f.as_ref())?;
// Stat the open FD (not the path) so we can't be raced between
// stat and open.
let length = file
.metadata()
.ok()
.filter(|m| m.is_file())
.map(|m| m.len());
Ok(Input {
reader: Box::new(BufReader::new(file)),
length,
})
}
None => Ok(Input {
// `Stdin` is `Send` (unlike `StdinLock`), so wrap it in a
// `BufReader` and box for cross-thread use in the parallel pipeline.
reader: Box::new(BufReader::new(io::stdin())),
length: None,
}),
}
}
#[derive(Clone, Debug, Default)]
pub struct OutSinkOptions {
pub force: bool,
pub input_file: Option<PathBuf>,
pub temp_dir: Option<PathBuf>,
pub buffer_verify_stdout: bool,
}
pub(crate) struct SecureTempFile {
path: PathBuf,
file: Option<File>,
remove_on_drop: bool,
}
impl SecureTempFile {
fn create(dir: &Path, prefix: &str) -> io::Result<Self> {
fs::create_dir_all(dir)?;
for _ in 0..128 {
let mut rand = [0u8; 16];
getrandom::fill(&mut rand).map_err(io::Error::other)?;
let name = format!("{prefix}.{}.tmp", hex(&rand));
let path = dir.join(name);
let mut opts = OpenOptions::new();
opts.read(true).write(true).create_new(true);
#[cfg(unix)]
{
use std::os::unix::fs::OpenOptionsExt;
opts.mode(0o600);
}
match opts.open(&path) {
Ok(file) => {
return Ok(Self {
path,
file: Some(file),
remove_on_drop: true,
});
}
Err(e) if e.kind() == io::ErrorKind::AlreadyExists => continue,
Err(e) => return Err(e),
}
}
Err(io::Error::new(
io::ErrorKind::AlreadyExists,
"could not create a unique temporary file after 128 attempts",
))
}
fn file_mut(&mut self) -> &mut File {
self.file
.as_mut()
.expect("temporary file handle taken before commit")
}
fn sync_file(&mut self) -> io::Result<()> {
let file = self.file_mut();
file.flush()?;
file.sync_all()
}
fn persist(mut self, final_path: &Path) -> io::Result<()> {
self.sync_file()?;
self.file.take();
#[cfg(windows)]
if final_path.exists() {
fs::remove_file(final_path)?;
}
fs::rename(&self.path, final_path)?;
self.remove_on_drop = false;
best_effort_fsync_parent(final_path);
Ok(())
}
fn copy_to_stdout(mut self) -> io::Result<()> {
self.sync_file()?;
let mut file = self
.file
.take()
.expect("temporary file handle taken before stdout commit");
file.seek(SeekFrom::Start(0))?;
let mut stdout = io::stdout();
io::copy(&mut file, &mut stdout)?;
stdout.flush()?;
Ok(())
}
}
impl Drop for SecureTempFile {
fn drop(&mut self) {
self.file.take();
if self.remove_on_drop {
let _ = fs::remove_file(&self.path);
}
}
}
fn hex(bytes: &[u8]) -> String {
const HEX: &[u8; 16] = b"0123456789abcdef";
let mut out = String::with_capacity(bytes.len() * 2);
for b in bytes {
out.push(HEX[(b >> 4) as usize] as char);
out.push(HEX[(b & 0x0f) as usize] as char);
}
out
}
fn best_effort_fsync_parent(path: &Path) {
let Some(parent) = path.parent() else {
return;
};
if let Ok(dir) = File::open(parent) {
let _ = dir.sync_all();
}
}
fn temp_dir_for_target(final_path: &Path, explicit: Option<&Path>) -> PathBuf {
if let Some(dir) = explicit {
return dir.to_path_buf();
}
final_path
.parent()
.filter(|p| !p.as_os_str().is_empty())
.map(Path::to_path_buf)
.unwrap_or_else(|| PathBuf::from("."))
}
fn temp_dir_for_stdout(explicit: Option<&Path>) -> PathBuf {
explicit
.map(Path::to_path_buf)
.unwrap_or_else(std::env::temp_dir)
}
fn file_name_prefix(path: &Path) -> String {
path.file_name()
.and_then(|name| name.to_str())
.filter(|name| !name.is_empty())
.unwrap_or("fcry")
.to_owned()
}
fn output_aliases_input(output: &Path, input: Option<&Path>) -> io::Result<bool> {
let Some(input) = input else {
return Ok(false);
};
match same_file::is_same_file(input, output) {
Ok(same) => Ok(same),
Err(e) if e.kind() == io::ErrorKind::NotFound => Ok(false),
Err(e) => Err(e),
}
}
/// Output sink that supports atomic file replacement.
///
/// For file outputs: bytes are written to `<path>.tmp`. On `commit()`, the
/// temp file is renamed into place. If dropped without commit (panic, error,
/// process exit), the temp file is deleted so a partial/garbage file does
/// not replace any existing target.
/// For file outputs: bytes are written to a private, randomly named temp file.
/// On `commit()`, the temp file is fsynced and renamed into place. If dropped
/// without commit (panic, error, process exit), the temp file is deleted so a
/// partial/garbage file does not replace any existing target.
///
/// For stdout: behaves as a passthrough; `commit()` is a no-op.
pub enum OutSink {
Stdout(io::Stdout),
BufferVerify {
temp: SecureTempFile,
},
File {
tmp_path: PathBuf,
final_path: PathBuf,
file: Option<File>,
committed: bool,
temp: SecureTempFile,
},
}
impl OutSink {
#[allow(dead_code)]
pub fn open<S: AsRef<str>>(output_file: Option<S>) -> io::Result<Self> {
Self::open_with_options(output_file, &OutSinkOptions::default())
}
pub fn open_with_options<S: AsRef<str>>(
output_file: Option<S>,
options: &OutSinkOptions,
) -> io::Result<Self> {
match output_file {
None if options.buffer_verify_stdout => {
let dir = temp_dir_for_stdout(options.temp_dir.as_deref());
Ok(Self::BufferVerify {
temp: SecureTempFile::create(&dir, "fcry-buffer")?,
})
}
None => Ok(Self::Stdout(io::stdout())),
Some(f) => {
let final_path = PathBuf::from(f.as_ref());
let mut tmp_path = final_path.clone();
let name = tmp_path
.file_name()
.map(|n| n.to_os_string())
.unwrap_or_default();
let mut tmp_name = name;
tmp_name.push(".tmp");
tmp_path.set_file_name(tmp_name);
let file = File::create(&tmp_path)?;
Ok(Self::File {
tmp_path,
final_path,
file: Some(file),
committed: false,
})
if final_path.exists()
&& !options.force
&& !output_aliases_input(&final_path, options.input_file.as_deref())?
{
return Err(io::Error::new(
io::ErrorKind::AlreadyExists,
format!(
"output file {} already exists (use --force to replace it)",
final_path.display()
),
));
}
let dir = temp_dir_for_target(&final_path, options.temp_dir.as_deref());
let prefix = file_name_prefix(&final_path);
let temp = SecureTempFile::create(&dir, &prefix)?;
Ok(Self::File { final_path, temp })
}
}
}
pub fn commit(mut self) -> io::Result<()> {
if let Self::File {
tmp_path,
final_path,
file,
committed,
} = &mut self
{
if let Some(mut f) = file.take() {
f.flush()?;
f.sync_all()?;
match &mut self {
Self::Stdout(s) => s.flush()?,
Self::BufferVerify { .. } => {}
Self::File { .. } => {}
}
fs::rename(&*tmp_path, &*final_path)?;
*committed = true;
match self {
Self::Stdout(_) => {}
Self::BufferVerify { temp } => temp.copy_to_stdout()?,
Self::File { final_path, temp } => temp.persist(&final_path)?,
}
Ok(())
}
@@ -83,33 +275,16 @@ impl Write for OutSink {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
match self {
Self::Stdout(s) => s.write(buf),
Self::File { file, .. } => file.as_mut().expect("file taken before commit").write(buf),
Self::BufferVerify { temp } => temp.file_mut().write(buf),
Self::File { temp, .. } => temp.file_mut().write(buf),
}
}
fn flush(&mut self) -> io::Result<()> {
match self {
Self::Stdout(s) => s.flush(),
Self::File { file, .. } => match file.as_mut() {
Some(f) => f.flush(),
None => Ok(()),
},
}
}
}
impl Drop for OutSink {
fn drop(&mut self) {
if let Self::File {
tmp_path,
committed,
file,
..
} = self
&& !*committed
{
file.take(); // close the file before unlink
let _ = fs::remove_file(tmp_path);
Self::BufferVerify { temp } => temp.file_mut().flush(),
Self::File { temp, .. } => temp.file_mut().flush(),
}
}
}
tests/roundtrip.rs
+841 -29
View File
@@ -1,4 +1,4 @@
// SPDX-License-Identifier: GPL-3.0-only
// SPDX-License-Identifier: MIT-0
//
// Integration tests for the `fcry` binary.
//
@@ -7,19 +7,28 @@
// wrong key, truncation, bad magic).
use std::fs;
use std::io::Write;
use std::io::{ErrorKind, Write};
use std::process::{Command, Stdio};
use assert_cmd::cargo::CommandCargoExt;
use tempfile::TempDir;
const KEY: &[u8; 32] = b"0123456789abcdef0123456789abcdef";
const KEY_STR: &str = "0123456789abcdef0123456789abcdef";
fn fcry() -> Command {
Command::cargo_bin("fcry").unwrap()
}
fn write_key_file(dir: &std::path::Path) -> std::path::PathBuf {
let key = dir.join("key.bin");
fs::write(&key, KEY).unwrap();
key
}
fn key_file_near(path: &std::path::Path) -> std::path::PathBuf {
write_key_file(path.parent().unwrap())
}
/// Deterministic pseudo-random plaintext of `n` bytes (xorshift, seedable).
/// We avoid `/dev/urandom` so tests are reproducible on failure.
fn pseudo_random(seed: u64, n: usize) -> Vec<u8> {
@@ -37,12 +46,13 @@ fn pseudo_random(seed: u64, n: usize) -> Vec<u8> {
fn encrypt_file(plain: &std::path::Path, ct: &std::path::Path, chunk_size: Option<u32>) {
let mut cmd = fcry();
let key = key_file_near(ct);
cmd.arg("-i")
.arg(plain)
.arg("-o")
.arg(ct)
.arg("--raw-key")
.arg(KEY_STR);
.arg("--key-file")
.arg(key);
if let Some(cs) = chunk_size {
cmd.arg("--chunk-size").arg(cs.to_string());
}
@@ -55,14 +65,15 @@ fn encrypt_file(plain: &std::path::Path, ct: &std::path::Path, chunk_size: Optio
}
fn decrypt_file(ct: &std::path::Path, rt: &std::path::Path) {
let key = key_file_near(ct);
let out = fcry()
.arg("-d")
.arg("-i")
.arg(ct)
.arg("-o")
.arg(rt)
.arg("--raw-key")
.arg(KEY_STR)
.arg("--key-file")
.arg(key)
.output()
.unwrap();
assert!(
@@ -133,10 +144,12 @@ fn roundtrip_chunk_size_one_byte() {
#[test]
fn roundtrip_pipe_stdin_stdout() {
let data = pseudo_random(42, 200_000);
let dir = TempDir::new().unwrap();
let key = write_key_file(dir.path());
let mut enc = fcry()
.arg("--raw-key")
.arg(KEY_STR)
.arg("--key-file")
.arg(&key)
.stdin(Stdio::piped())
.stdout(Stdio::piped())
.stderr(Stdio::piped())
@@ -152,8 +165,8 @@ fn roundtrip_pipe_stdin_stdout() {
let mut dec = fcry()
.arg("-d")
.arg("--raw-key")
.arg(KEY_STR)
.arg("--key-file")
.arg(&key)
.stdin(Stdio::piped())
.stdout(Stdio::piped())
.stderr(Stdio::piped())
@@ -182,19 +195,24 @@ fn rejects_wrong_key() {
fs::write(&plain, pseudo_random(1, 1000)).unwrap();
encrypt_file(&plain, &ct, None);
let wrong = "ffffffffffffffffffffffffffffffff";
assert_ne!(wrong.as_bytes(), KEY);
let wrong = dir.path().join("wrong.key");
fs::write(&wrong, b"ffffffffffffffffffffffffffffffff").unwrap();
let out = fcry()
.arg("-d")
.arg("-i")
.arg(&ct)
.arg("-o")
.arg(dir.path().join("rt.bin"))
.arg("--raw-key")
.arg("--key-file")
.arg(wrong)
.output()
.unwrap();
assert!(!out.status.success(), "decrypt with wrong key should fail");
assert!(
String::from_utf8_lossy(&out.stderr).contains("WrongKey"),
"expected distinct WrongKey error, got {}",
String::from_utf8_lossy(&out.stderr)
);
}
#[test]
@@ -216,8 +234,8 @@ fn rejects_tampered_header() {
.arg(&ct)
.arg("-o")
.arg(dir.path().join("rt.bin"))
.arg("--raw-key")
.arg(KEY_STR)
.arg("--key-file")
.arg(key_file_near(&ct))
.output()
.unwrap();
assert!(
@@ -246,8 +264,8 @@ fn rejects_tampered_ciphertext() {
.arg(&ct)
.arg("-o")
.arg(dir.path().join("rt.bin"))
.arg("--raw-key")
.arg(KEY_STR)
.arg("--key-file")
.arg(key_file_near(&ct))
.output()
.unwrap();
assert!(
@@ -275,8 +293,8 @@ fn rejects_truncated_ciphertext() {
.arg(&ct)
.arg("-o")
.arg(dir.path().join("rt.bin"))
.arg("--raw-key")
.arg(KEY_STR)
.arg("--key-file")
.arg(key_file_near(&ct))
.output()
.unwrap();
assert!(
@@ -296,8 +314,8 @@ fn rejects_bad_magic() {
.arg(&bogus)
.arg("-o")
.arg(dir.path().join("rt.bin"))
.arg("--raw-key")
.arg(KEY_STR)
.arg("--key-file")
.arg(write_key_file(dir.path()))
.output()
.unwrap();
assert!(
@@ -312,25 +330,145 @@ fn rejects_bad_magic() {
}
#[test]
fn rejects_short_raw_key() {
fn rejects_short_key_file() {
let dir = TempDir::new().unwrap();
let plain = dir.path().join("p.bin");
let key = dir.path().join("short.key");
fs::write(&plain, b"hello").unwrap();
fs::write(&key, b"tooshort").unwrap();
let out = fcry()
.arg("-i")
.arg(&plain)
.arg("-o")
.arg(dir.path().join("c.bin"))
.arg("--raw-key")
.arg("tooshort")
.arg("--key-file")
.arg(&key)
.output()
.unwrap();
assert!(
!out.status.success(),
"encrypt with short raw_key should fail"
"encrypt with short key file should fail"
);
}
#[test]
fn rejects_long_key_file_and_trailing_newline() {
let dir = TempDir::new().unwrap();
let plain = dir.path().join("p.bin");
let key = dir.path().join("long.key");
fs::write(&plain, b"hello").unwrap();
fs::write(&key, b"0123456789abcdef0123456789abcdef\n").unwrap();
let out = fcry()
.arg("-i")
.arg(&plain)
.arg("-o")
.arg(dir.path().join("c.bin"))
.arg("--key-file")
.arg(&key)
.output()
.unwrap();
assert!(!out.status.success(), "long key file should fail");
assert!(
String::from_utf8_lossy(&out.stderr).contains("too long"),
"expected too-long error, got {}",
String::from_utf8_lossy(&out.stderr)
);
}
#[test]
fn non_utf8_key_file_roundtrips() {
let dir = TempDir::new().unwrap();
let key = dir.path().join("key.bin");
let plain = dir.path().join("plain.bin");
let ct = dir.path().join("ct.bin");
let rt = dir.path().join("rt.bin");
let key_bytes: Vec<u8> = (0..32u8).map(|b| b ^ 0x80).collect();
let data = pseudo_random(31, 8192);
fs::write(&key, key_bytes).unwrap();
fs::write(&plain, &data).unwrap();
let enc = fcry()
.arg("-i")
.arg(&plain)
.arg("-o")
.arg(&ct)
.arg("--key-file")
.arg(&key)
.output()
.unwrap();
assert!(
enc.status.success(),
"non-UTF-8 key encrypt failed: {}",
String::from_utf8_lossy(&enc.stderr)
);
let dec = fcry()
.arg("-d")
.arg("-i")
.arg(&ct)
.arg("-o")
.arg(&rt)
.arg("--key-file")
.arg(&key)
.output()
.unwrap();
assert!(
dec.status.success(),
"non-UTF-8 key decrypt failed: {}",
String::from_utf8_lossy(&dec.stderr)
);
assert_eq!(fs::read(&rt).unwrap(), data);
}
#[cfg(unix)]
#[test]
fn split_fifo_key_file_read_roundtrips() {
use std::ffi::CString;
use std::fs::OpenOptions;
use std::os::unix::ffi::OsStrExt;
use std::thread;
use std::time::Duration;
let dir = TempDir::new().unwrap();
let fifo = dir.path().join("key.fifo");
let fifo_c = CString::new(fifo.as_os_str().as_bytes()).unwrap();
let rc = unsafe { libc::mkfifo(fifo_c.as_ptr(), 0o600) };
assert_eq!(rc, 0, "mkfifo failed: {}", std::io::Error::last_os_error());
let plain = dir.path().join("plain.bin");
let ct = dir.path().join("ct.bin");
let rt = dir.path().join("rt.bin");
let data = pseudo_random(33, 8192);
fs::write(&plain, &data).unwrap();
let fifo_writer = fifo.clone();
let writer = thread::spawn(move || {
let mut file = OpenOptions::new().write(true).open(&fifo_writer).unwrap();
file.write_all(&KEY[..8]).unwrap();
file.flush().unwrap();
thread::sleep(Duration::from_millis(50));
file.write_all(&KEY[8..]).unwrap();
});
let enc = fcry()
.arg("-i")
.arg(&plain)
.arg("-o")
.arg(&ct)
.arg("--key-file")
.arg(&fifo)
.output()
.unwrap();
writer.join().unwrap();
assert!(
enc.status.success(),
"split FIFO key encrypt failed: {}",
String::from_utf8_lossy(&enc.stderr)
);
decrypt_file(&ct, &rt);
assert_eq!(fs::read(&rt).unwrap(), data);
}
#[test]
fn roundtrip_passphrase_argon2id() {
let dir = TempDir::new().unwrap();
@@ -352,6 +490,7 @@ fn roundtrip_passphrase_argon2id() {
.arg("8")
.arg("--argon-passes")
.arg("1")
.arg("--allow-weak-kdf")
.env("FCRY_TEST_PW", "correct horse battery staple")
.output()
.unwrap();
@@ -394,6 +533,70 @@ fn roundtrip_passphrase_argon2id() {
assert!(!bad.status.success(), "wrong passphrase should fail");
}
#[test]
fn weak_passphrase_kdf_rejected_without_override() {
let dir = TempDir::new().unwrap();
let plain = dir.path().join("p.bin");
fs::write(&plain, b"hello").unwrap();
let enc = fcry()
.arg("-i")
.arg(&plain)
.arg("-o")
.arg(dir.path().join("c.bin"))
.arg("--passphrase-env")
.arg("FCRY_TEST_PW")
.arg("--argon-memory")
.arg("8")
.arg("--argon-passes")
.arg("1")
.env("FCRY_TEST_PW", "short")
.output()
.unwrap();
assert!(!enc.status.success(), "weak KDF/passphrase should fail");
}
#[test]
fn decrypt_argon_memory_cap_rejects_hostile_header() {
let dir = TempDir::new().unwrap();
let plain = dir.path().join("p.bin");
let ct = dir.path().join("c.bin");
fs::write(&plain, b"hello").unwrap();
let enc = fcry()
.arg("-i")
.arg(&plain)
.arg("-o")
.arg(&ct)
.arg("--passphrase-env")
.arg("FCRY_TEST_PW")
.arg("--argon-memory")
.arg("8")
.arg("--argon-passes")
.arg("1")
.arg("--allow-weak-kdf")
.env("FCRY_TEST_PW", "correct horse battery staple")
.output()
.unwrap();
assert!(enc.status.success());
let dec = fcry()
.arg("-d")
.arg("-i")
.arg(&ct)
.arg("--passphrase-env")
.arg("FCRY_TEST_PW")
.arg("--max-argon-memory-mib")
.arg("1")
.env("FCRY_TEST_PW", "correct horse battery staple")
.output()
.unwrap();
assert!(!dec.status.success(), "low decrypt cap should reject file");
assert!(
String::from_utf8_lossy(&dec.stderr).contains("decrypt cap"),
"expected cap error, got {}",
String::from_utf8_lossy(&dec.stderr)
);
}
#[test]
fn atomic_output_no_stale_tmp_on_failure() {
// A failed decrypt (wrong key) should not leave the output file behind.
@@ -404,15 +607,16 @@ fn atomic_output_no_stale_tmp_on_failure() {
fs::write(&plain, b"hello world").unwrap();
encrypt_file(&plain, &ct, None);
let wrong = "ffffffffffffffffffffffffffffffff";
let wrong = dir.path().join("wrong.key");
fs::write(&wrong, b"ffffffffffffffffffffffffffffffff").unwrap();
let out = fcry()
.arg("-d")
.arg("-i")
.arg(&ct)
.arg("-o")
.arg(&rt)
.arg("--raw-key")
.arg(wrong)
.arg("--key-file")
.arg(&wrong)
.output()
.unwrap();
assert!(!out.status.success());
@@ -422,6 +626,614 @@ fn atomic_output_no_stale_tmp_on_failure() {
assert!(!tmp.exists(), "temp file must be cleaned up");
}
#[test]
fn existing_output_refuses_without_force() {
let dir = TempDir::new().unwrap();
let plain = dir.path().join("p.bin");
let ct = dir.path().join("c.bin");
fs::write(&plain, b"hello").unwrap();
fs::write(&ct, b"existing").unwrap();
let out = fcry()
.arg("-i")
.arg(&plain)
.arg("-o")
.arg(&ct)
.arg("--key-file")
.arg(write_key_file(dir.path()))
.output()
.unwrap();
assert!(!out.status.success(), "existing output should refuse");
assert_eq!(fs::read(&ct).unwrap(), b"existing");
}
#[test]
fn force_replaces_only_after_success() {
let dir = TempDir::new().unwrap();
let plain = dir.path().join("p.bin");
let ct = dir.path().join("c.bin");
fs::write(&plain, b"hello").unwrap();
fs::write(&ct, b"existing").unwrap();
let out = fcry()
.arg("-i")
.arg(&plain)
.arg("-o")
.arg(&ct)
.arg("--force")
.arg("--key-file")
.arg(write_key_file(dir.path()))
.output()
.unwrap();
assert!(
out.status.success(),
"force encrypt failed: {}",
String::from_utf8_lossy(&out.stderr)
);
assert_ne!(fs::read(&ct).unwrap(), b"existing");
}
#[test]
fn in_place_replacement_roundtrips() {
let dir = TempDir::new().unwrap();
let path = dir.path().join("data.bin");
let original = pseudo_random(41, 50_000);
fs::write(&path, &original).unwrap();
let enc = fcry()
.arg("-i")
.arg(&path)
.arg("-o")
.arg(&path)
.arg("--key-file")
.arg(write_key_file(dir.path()))
.output()
.unwrap();
assert!(
enc.status.success(),
"in-place encrypt failed: {}",
String::from_utf8_lossy(&enc.stderr)
);
assert_ne!(fs::read(&path).unwrap(), original);
let dec = fcry()
.arg("-d")
.arg("-i")
.arg(&path)
.arg("-o")
.arg(&path)
.arg("--key-file")
.arg(write_key_file(dir.path()))
.output()
.unwrap();
assert!(
dec.status.success(),
"in-place decrypt failed: {}",
String::from_utf8_lossy(&dec.stderr)
);
assert_eq!(fs::read(&path).unwrap(), original);
}
#[test]
fn old_predictable_temp_name_input_is_not_truncated() {
let dir = TempDir::new().unwrap();
let input = dir.path().join("out.bin.tmp");
let output = dir.path().join("out.bin");
let original = pseudo_random(42, 1024);
fs::write(&input, &original).unwrap();
let out = fcry()
.arg("-i")
.arg(&input)
.arg("-o")
.arg(&output)
.arg("--key-file")
.arg(write_key_file(dir.path()))
.output()
.unwrap();
assert!(
out.status.success(),
"encrypt failed: {}",
String::from_utf8_lossy(&out.stderr)
);
assert_eq!(fs::read(&input).unwrap(), original);
assert!(output.exists());
}
#[cfg(unix)]
#[test]
fn output_file_mode_is_0600() {
use std::os::unix::fs::PermissionsExt;
let dir = TempDir::new().unwrap();
let plain = dir.path().join("p.bin");
let ct = dir.path().join("c.bin");
fs::write(&plain, b"hello").unwrap();
encrypt_file(&plain, &ct, None);
let mode = fs::metadata(&ct).unwrap().permissions().mode() & 0o777;
assert_eq!(mode, 0o600);
}
// ---------------------------------------------------------------------------
// Multi-threaded pipeline + length-committed + random-access tests
// ---------------------------------------------------------------------------
fn encrypt_file_threads(
plain: &std::path::Path,
ct: &std::path::Path,
chunk_size: Option<u32>,
threads: usize,
) {
let mut cmd = fcry();
let key = key_file_near(ct);
cmd.arg("-i")
.arg(plain)
.arg("-o")
.arg(ct)
.arg("--key-file")
.arg(key)
.arg("-j")
.arg(threads.to_string());
if let Some(cs) = chunk_size {
cmd.arg("--chunk-size").arg(cs.to_string());
}
let out = cmd.output().unwrap();
assert!(
out.status.success(),
"encrypt -j{threads} failed: {}",
String::from_utf8_lossy(&out.stderr)
);
}
fn decrypt_file_threads(ct: &std::path::Path, rt: &std::path::Path, threads: usize) {
let key = key_file_near(ct);
let out = fcry()
.arg("-d")
.arg("-i")
.arg(ct)
.arg("-o")
.arg(rt)
.arg("--key-file")
.arg(key)
.arg("-j")
.arg(threads.to_string())
.output()
.unwrap();
assert!(
out.status.success(),
"decrypt -j{threads} failed: {}",
String::from_utf8_lossy(&out.stderr)
);
}
#[test]
fn roundtrip_multi_threaded() {
// Multi-chunk input. Encrypt+decrypt with -j 4 must round-trip.
let dir = TempDir::new().unwrap();
let plain = dir.path().join("p.bin");
let ct = dir.path().join("c.bin");
let rt = dir.path().join("r.bin");
let data = pseudo_random(11, 5 * 1024 * 1024 + 12345);
fs::write(&plain, &data).unwrap();
encrypt_file_threads(&plain, &ct, Some(64 * 1024), 4);
decrypt_file_threads(&ct, &rt, 4);
assert_eq!(fs::read(&rt).unwrap(), data);
}
#[test]
fn parallel_and_serial_outputs_round_trip() {
// Encrypt with -j 4 and decrypt serially (and vice-versa); both directions
// must yield the original plaintext.
let dir = TempDir::new().unwrap();
let plain = dir.path().join("p.bin");
let data = pseudo_random(13, 256 * 1024 + 17);
fs::write(&plain, &data).unwrap();
let ct_par = dir.path().join("c_par.bin");
let ct_ser = dir.path().join("c_ser.bin");
encrypt_file_threads(&plain, &ct_par, Some(8192), 4);
encrypt_file_threads(&plain, &ct_ser, Some(8192), 1);
let rt1 = dir.path().join("r1.bin");
let rt2 = dir.path().join("r2.bin");
// par-encrypted, serial-decrypted
decrypt_file_threads(&ct_par, &rt1, 1);
// serial-encrypted, par-decrypted
decrypt_file_threads(&ct_ser, &rt2, 4);
assert_eq!(fs::read(&rt1).unwrap(), data);
assert_eq!(fs::read(&rt2).unwrap(), data);
}
#[test]
fn roundtrip_pipe_multi_threaded() {
// stdin/stdout mode with -j 4: length flag must NOT be set (no committed
// length when we don't know the input size), but encrypt/decrypt must still
// round-trip cleanly across the pipeline.
let data = pseudo_random(14, 200_000);
let dir = TempDir::new().unwrap();
let key = write_key_file(dir.path());
let mut enc = fcry()
.arg("--key-file")
.arg(&key)
.arg("-j")
.arg("4")
.stdin(Stdio::piped())
.stdout(Stdio::piped())
.stderr(Stdio::piped())
.spawn()
.unwrap();
enc.stdin.as_mut().unwrap().write_all(&data).unwrap();
let enc_out = enc.wait_with_output().unwrap();
assert!(
enc_out.status.success(),
"pipe encrypt -j4 failed: {}",
String::from_utf8_lossy(&enc_out.stderr)
);
// flags byte at offset 6 must not set length commitment for stdin input.
assert_eq!(
enc_out.stdout[6] & 0x01,
0,
"stdin-encrypted file unexpectedly committed length"
);
let mut dec = fcry()
.arg("-d")
.arg("--key-file")
.arg(&key)
.arg("-j")
.arg("4")
.stdin(Stdio::piped())
.stdout(Stdio::piped())
.stderr(Stdio::piped())
.spawn()
.unwrap();
dec.stdin
.as_mut()
.unwrap()
.write_all(&enc_out.stdout)
.unwrap();
let dec_out = dec.wait_with_output().unwrap();
assert!(
dec_out.status.success(),
"pipe decrypt -j4 failed: {}",
String::from_utf8_lossy(&dec_out.stderr)
);
assert_eq!(dec_out.stdout, data);
}
#[test]
fn stdin_chunk_size_zero_fails_but_empty_valid_chunk_succeeds() {
let dir = TempDir::new().unwrap();
let key = write_key_file(dir.path());
let mut bad = fcry()
.arg("--chunk-size")
.arg("0")
.arg("--key-file")
.arg(&key)
.stdin(Stdio::piped())
.stdout(Stdio::piped())
.stderr(Stdio::piped())
.spawn()
.unwrap();
// Invalid options can make the child exit before it drains stdin.
if let Err(err) = bad.stdin.as_mut().unwrap().write_all(b"x") {
assert_eq!(
err.kind(),
ErrorKind::BrokenPipe,
"unexpected stdin write error for failing chunk-size 0 process: {err}"
);
}
let bad_out = bad.wait_with_output().unwrap();
assert!(!bad_out.status.success(), "chunk-size 0 should fail");
let mut good = fcry()
.arg("--chunk-size")
.arg("1")
.arg("--key-file")
.arg(&key)
.stdin(Stdio::piped())
.stdout(Stdio::piped())
.stderr(Stdio::piped())
.spawn()
.unwrap();
drop(good.stdin.take());
let good_out = good.wait_with_output().unwrap();
assert!(
good_out.status.success(),
"empty stdin with valid chunk should succeed: {}",
String::from_utf8_lossy(&good_out.stderr)
);
}
#[test]
fn huge_thread_count_is_bounded() {
let dir = TempDir::new().unwrap();
let plain = dir.path().join("p.bin");
let ct = dir.path().join("c.bin");
fs::write(&plain, b"hello").unwrap();
let out = fcry()
.arg("-i")
.arg(&plain)
.arg("-o")
.arg(&ct)
.arg("--key-file")
.arg(write_key_file(dir.path()))
.arg("-j")
.arg("1000000")
.output()
.unwrap();
assert!(
out.status.success(),
"huge -j should be capped, got {}",
String::from_utf8_lossy(&out.stderr)
);
assert!(String::from_utf8_lossy(&out.stderr).contains("capped"));
}
#[test]
fn forged_huge_chunk_header_fails_before_allocation() {
let dir = TempDir::new().unwrap();
let forged = dir.path().join("forged.bin");
let mut bytes = Vec::new();
bytes.extend_from_slice(b"fcry");
bytes.push(3); // version
bytes.push(1); // alg
bytes.push(0x02); // key commitment flag
bytes.push(0); // reserved
bytes.extend_from_slice(&u32::MAX.to_le_bytes());
fs::write(&forged, bytes).unwrap();
let out = fcry()
.arg("-d")
.arg("-i")
.arg(&forged)
.arg("--key-file")
.arg(write_key_file(dir.path()))
.output()
.unwrap();
assert!(!out.status.success(), "huge chunk header should fail");
assert!(
String::from_utf8_lossy(&out.stderr).contains("chunk_size"),
"expected chunk_size error, got {}",
String::from_utf8_lossy(&out.stderr)
);
}
#[test]
fn file_input_commits_length() {
// Encrypting from a regular file must auto-set FLAG_LENGTH_COMMITTED (bit 0
// of the flags byte at offset 6) and embed the length.
let dir = TempDir::new().unwrap();
let plain = dir.path().join("p.bin");
let ct = dir.path().join("c.bin");
let data = pseudo_random(15, 50_000);
fs::write(&plain, &data).unwrap();
encrypt_file(&plain, &ct, Some(4096));
let bytes = fs::read(&ct).unwrap();
// Magic(4) + version(1) + alg(1) + flags(1) = byte 6
assert_eq!(bytes[4], 3, "version should be 3");
assert_eq!(bytes[6] & 0x01, 0x01, "length-committed flag should be set");
assert_eq!(bytes[6] & 0x02, 0x02, "key-committed flag should be set");
}
#[test]
fn v3_downgrade_or_commitment_stripping_fails_authentication() {
let dir = TempDir::new().unwrap();
let plain = dir.path().join("p.bin");
let ct = dir.path().join("c.bin");
let rt = dir.path().join("r.bin");
fs::write(&plain, pseudo_random(51, 1000)).unwrap();
encrypt_file(&plain, &ct, None);
let mut bytes = fs::read(&ct).unwrap();
bytes[4] = 2;
bytes[6] &= !0x02;
fs::write(&ct, bytes).unwrap();
let out = fcry()
.arg("-d")
.arg("-i")
.arg(&ct)
.arg("-o")
.arg(&rt)
.arg("--key-file")
.arg(key_file_near(&ct))
.output()
.unwrap();
assert!(
!out.status.success(),
"downgraded/stripped v3 header must fail authentication"
);
}
fn encrypt_random_access_fixture(
dir: &std::path::Path,
data: &[u8],
chunk_size: u32,
) -> std::path::PathBuf {
let plain = dir.join("p.bin");
let ct = dir.join("c.bin");
fs::write(&plain, data).unwrap();
encrypt_file(&plain, &ct, Some(chunk_size));
ct
}
fn random_access_decrypt(
ct: &std::path::Path,
out: &std::path::Path,
offset: u64,
length: u64,
) -> std::process::Output {
fcry()
.arg("-d")
.arg("-i")
.arg(ct)
.arg("-o")
.arg(out)
.arg("--key-file")
.arg(key_file_near(ct))
.arg("--offset")
.arg(offset.to_string())
.arg("--length")
.arg(length.to_string())
.output()
.unwrap()
}
#[test]
fn random_access_decrypt_slices() {
let dir = TempDir::new().unwrap();
let chunk = 4096u32;
let total = 5 * 1024 * 1024 + 12345;
let data = pseudo_random(16, total);
let ct = encrypt_random_access_fixture(dir.path(), &data, chunk);
// (offset, length) cases:
// - chunk-aligned start, mid-chunk end
// - mid-chunk start crossing several chunks
// - last partial chunk
// - last byte
// - entire file
let cases: &[(u64, u64)] = &[
(0, 1),
(chunk as u64, 7),
(chunk as u64 - 5, 100),
(10, chunk as u64 * 3 + 17),
(total as u64 - 1, 1),
(total as u64 - 100, 100),
(0, total as u64),
];
for (i, (offset, length)) in cases.iter().copied().enumerate() {
let out = dir.path().join(format!("slice_{i}.bin"));
let r = random_access_decrypt(&ct, &out, offset, length);
assert!(
r.status.success(),
"slice {i} ({offset}, {length}) failed: {}",
String::from_utf8_lossy(&r.stderr)
);
let got = fs::read(&out).unwrap();
let expected = &data[offset as usize..(offset + length) as usize];
assert_eq!(got, expected, "slice {i} mismatch");
}
}
#[test]
fn random_access_rejects_out_of_range() {
let dir = TempDir::new().unwrap();
let data = pseudo_random(17, 1000);
let ct = encrypt_random_access_fixture(dir.path(), &data, 256);
let out = dir.path().join("oob.bin");
let r = random_access_decrypt(&ct, &out, 900, 1000); // 900+1000 > 1000
assert!(!r.status.success(), "out-of-range slice should fail");
}
#[test]
fn random_access_rejects_stdin_encrypted() {
// Encrypt via stdin → no length committed → random access must refuse.
let data = pseudo_random(18, 2000);
let dir = TempDir::new().unwrap();
let ct = dir.path().join("c.bin");
let key = write_key_file(dir.path());
let mut enc = fcry()
.arg("--key-file")
.arg(&key)
.arg("-o")
.arg(&ct)
.stdin(Stdio::piped())
.stderr(Stdio::piped())
.spawn()
.unwrap();
enc.stdin.as_mut().unwrap().write_all(&data).unwrap();
assert!(enc.wait().unwrap().success());
let out = dir.path().join("slice.bin");
let r = random_access_decrypt(&ct, &out, 0, 100);
assert!(
!r.status.success(),
"random access on stdin-encrypted file should fail"
);
}
#[test]
fn random_access_rejects_zero_length() {
let dir = TempDir::new().unwrap();
let data = pseudo_random(19, 1000);
let ct = encrypt_random_access_fixture(dir.path(), &data, 256);
let out = dir.path().join("empty.bin");
let r = random_access_decrypt(&ct, &out, 500, 0);
assert!(!r.status.success(), "zero-length slice should fail");
}
#[test]
fn random_access_tampered_length_fails() {
// Flip a byte inside the committed plaintext_length field. The header is
// AAD for every chunk, so the AEAD must reject decryption.
let dir = TempDir::new().unwrap();
let data = pseudo_random(20, 4000);
let ct = encrypt_random_access_fixture(dir.path(), &data, 1024);
let mut bytes = fs::read(&ct).unwrap();
// For raw-kdf header: magic(4)+ver(1)+alg(1)+flags(1)+rsv(1)+chunksize(4)+kdf_id(1)+nonce_prefix(19) = 32
// plaintext_length is at offset 32..40.
bytes[34] ^= 0xff;
fs::write(&ct, &bytes).unwrap();
let out = dir.path().join("bad.bin");
let r = random_access_decrypt(&ct, &out, 0, 100);
assert!(
!r.status.success(),
"tampered plaintext_length must fail authentication"
);
}
#[test]
fn buffer_verify_stdout_emits_nothing_on_truncated_ciphertext() {
let dir = TempDir::new().unwrap();
let plain = dir.path().join("p.bin");
let ct = dir.path().join("c.bin");
fs::write(&plain, pseudo_random(61, 3 * 1024 * 1024)).unwrap();
encrypt_file(&plain, &ct, Some(64 * 1024));
let mut bytes = fs::read(&ct).unwrap();
bytes.truncate(bytes.len() - 32);
fs::write(&ct, bytes).unwrap();
let out = fcry()
.arg("-d")
.arg("-i")
.arg(&ct)
.arg("--buffer-verify")
.arg("--key-file")
.arg(key_file_near(&ct))
.output()
.unwrap();
assert!(!out.status.success(), "truncated decrypt should fail");
assert!(
out.stdout.is_empty(),
"buffer-verify must suppress partial stdout"
);
}
#[test]
fn rejects_zero_threads() {
// -j 0 is almost certainly a user mistake. Clap should reject it before
// we ever reach the pipeline.
let dir = TempDir::new().unwrap();
let plain = dir.path().join("p.bin");
fs::write(&plain, b"hello").unwrap();
let out = fcry()
.arg("-i")
.arg(&plain)
.arg("-o")
.arg(dir.path().join("c.bin"))
.arg("--key-file")
.arg(write_key_file(dir.path()))
.arg("-j")
.arg("0")
.output()
.unwrap();
assert!(!out.status.success(), "-j 0 should be rejected");
}
#[test]
fn header_chunk_size_is_authoritative_on_decrypt() {
// Encrypt with a non-default chunk size; decrypt without specifying one.