ddidderr/zstd-rs
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

feat(compress): validate stable buffers in Rust

Browse Source 
Keep the private ZSTD_CCtx and public buffer structures in C while moving the
read-only stable-buffer validation policy behind a scalar ABI. The Rust helper
compares expected and current input pointers and positions without dereferencing
raw pointers, and uses wrapping subtraction for the stable output remainder.
The C wrapper still extracts the context and buffer fields, and the existing
compressStream2 FORWARD_IF_ERROR path remains responsible for propagating the
encoded stability error. The unused endOp parameter is no longer carried into
the validation helper.

Test Plan:
- `cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression` -- passed, 309 tests.
- All three requested clippy modes passed before and after `cargo +nightly fmt --manifest-path rust/Cargo.toml`.
- `make -B -C lib -j2 lib` -- passed.
- `make -C tests test-rust-lib-smoke` -- passed.
- `tests/fuzzer -s4560 -t56 -i57 -v` -- passed.
- `make -C tests -j2 test-zstream` -- passed, 84 named plus 5,333 and 8,072 randomized cases.
- `git diff --check` and `git diff --cached --check` -- passed.
- `make -C tests -j2 test-zstream32` -- unavailable because the i686 Rust target is not installed.
This commit is contained in:
ddidderr
2026-07-18 12:35:34 +02:00
parent 2afeb6ec25
commit fe0ace0370
2 changed files with 212 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files
rust/src/zstd_compress.rs
+195
View File
@@ -198,6 +198,61 @@ pub extern "C" fn ZSTD_rust_inBufferForEndFlush(
}
}
#[inline]
fn check_buffer_stability(
in_buffer_mode: c_int,
out_buffer_mode: c_int,
expected_in_src: *const c_void,
expected_in_pos: usize,
input_src: *const c_void,
input_pos: usize,
expected_out_buffer_size: usize,
output_size: usize,
output_pos: usize,
) -> usize {
if in_buffer_mode == ZSTD_BM_STABLE
&& (expected_in_src != input_src || expected_in_pos != input_pos)
{
return ERROR(ZstdErrorCode::StabilityConditionNotRespected);
}
if out_buffer_mode == ZSTD_BM_STABLE
&& expected_out_buffer_size != output_size.wrapping_sub(output_pos)
{
return ERROR(ZstdErrorCode::StabilityConditionNotRespected);
}
0
}
/// Validate the stable input/output buffer expectations without crossing the
/// private `ZSTD_CCtx` layout into Rust. Raw pointers are compared only for
/// identity and are never dereferenced.
#[no_mangle]
pub extern "C" fn ZSTD_rust_checkBufferStability(
in_buffer_mode: c_int,
out_buffer_mode: c_int,
expected_in_src: *const c_void,
expected_in_pos: usize,
input_src: *const c_void,
input_pos: usize,
expected_out_buffer_size: usize,
output_size: usize,
output_pos: usize,
) -> usize {
check_buffer_stability(
in_buffer_mode,
out_buffer_mode,
expected_in_src,
expected_in_pos,
input_src,
input_pos,
expected_out_buffer_size,
output_size,
output_pos,
)
}
#[inline]
fn select_sequence_copier(mode: c_int) -> c_int {
debug_assert!(
@@ -1404,6 +1459,146 @@ mod tests {
}
}
#[test]
fn check_buffer_stability_accepts_matching_stable_input() {
let expected_src = b"input".as_ptr().cast::<c_void>();
assert_eq!(
check_buffer_stability(
ZSTD_BM_STABLE,
ZSTD_BM_BUFFERED,
expected_src,
11,
expected_src,
11,
0,
37,
5,
),
0
);
assert_eq!(
ZSTD_rust_checkBufferStability(
ZSTD_BM_STABLE,
ZSTD_BM_BUFFERED,
expected_src,
11,
expected_src,
11,
0,
37,
5,
),
0
);
}
#[test]
fn check_buffer_stability_rejects_changed_input_pointer_or_position() {
let expected_src = b"input".as_ptr().cast::<c_void>();
let other_src = b"other".as_ptr().cast::<c_void>();
let error = ERROR(ZstdErrorCode::StabilityConditionNotRespected);
assert_eq!(
ZSTD_rust_checkBufferStability(
ZSTD_BM_STABLE,
ZSTD_BM_BUFFERED,
expected_src,
11,
other_src,
11,
0,
37,
5,
),
error
);
assert_eq!(
ZSTD_rust_checkBufferStability(
ZSTD_BM_STABLE,
ZSTD_BM_BUFFERED,
expected_src,
11,
expected_src,
12,
0,
37,
5,
),
error
);
}
#[test]
fn check_buffer_stability_ignores_input_changes_in_buffered_mode() {
let expected_src = b"input".as_ptr().cast::<c_void>();
let other_src = b"other".as_ptr().cast::<c_void>();
assert_eq!(
ZSTD_rust_checkBufferStability(
ZSTD_BM_BUFFERED,
ZSTD_BM_BUFFERED,
expected_src,
11,
other_src,
12,
0,
37,
5,
),
0
);
}
#[test]
fn check_buffer_stability_validates_stable_output_remainder() {
let expected_src = b"input".as_ptr().cast::<c_void>();
let error = ERROR(ZstdErrorCode::StabilityConditionNotRespected);
assert_eq!(
ZSTD_rust_checkBufferStability(
ZSTD_BM_BUFFERED,
ZSTD_BM_STABLE,
expected_src,
0,
ptr::null(),
0,
32,
40,
8,
),
0
);
assert_eq!(
ZSTD_rust_checkBufferStability(
ZSTD_BM_BUFFERED,
ZSTD_BM_STABLE,
expected_src,
0,
ptr::null(),
0,
32,
40,
7,
),
error
);
assert_eq!(
ZSTD_rust_checkBufferStability(
ZSTD_BM_BUFFERED,
ZSTD_BM_STABLE,
expected_src,
0,
ptr::null(),
0,
usize::MAX,
3,
4,
),
0
);
}
#[test]
fn sequence_copier_selector_returns_no_delimiters_mode() {
assert_eq!(