forked from unom/punktfunk
enricobuehler
aa070f2d55
The sharpest memory-safety risk left in this codebase is not an `unsafe` block — it is a hand-written `#[repr(C)]` mirror of an external C struct. Get a field offset wrong and nothing fails to compile and nothing reliably crashes: the library reads a pointer, a length or a pitch out of the wrong bytes. Eleven such structs across five files had NO check at all. Guarded here, each next to the struct it protects: * `AVCUDADeviceContext`, and `AVD3D11VADeviceContext`/`AVD3D11VAFramesContext`. `ffmpeg-sys-next` binds none of them, so these mirrors are the only definitions — and we WRITE through them (`cuda_ctx`, `device`, `bind_flags`). ⚠ The D3D11VA pair is duplicated VERBATIM in two crates (pf-encode's `ffmpeg_win.rs`, pf-client-core's `video_d3d11.rs`) because neither can depend on the other; they must agree with libav and with each other, and now a drift in either is a build error. * The six cuda.h structs. Three were already asserted — but only in `#[cfg(test)]`, so the check ran when someone ran the tests and never in a release build. They are `const` now. The other three, including `CUDA_MEMCPY2D` which is filled on EVERY zero-copy frame, had nothing. * `MsghdrX`, Darwin's `msghdr_x`, which `libc` does not expose. Its layout is not reviewable by eye: the 32-bit fields force padding before each following pointer, so `msg_iov` sits at 16 and not 12. `sendmsg_x`/`recvmsg_x` take the pointer and length from it. * `IPolicyConfigVtbl` — the sharpest of the set. It mirrors an UNDOCUMENTED COM interface, and `set_default_endpoint` is called by SLOT INDEX through a ten-entry `_reserved` gap that carries no names to anchor a review. A field added or resized above it does not break the build; it calls a different function pointer through a mismatched signature. Every assertion is `const _: () = assert!(..)`, so it holds on every build including release and cannot be skipped. The compiler verified the numbers — the sizes and offsets asserted here are the ones the target actually produces, on each platform that compiles the struct. Verified: Linux .21 fmt + both CI clippy steps rc=0 (CUDA + libav CUDA mirrors); Windows .47 full CI clippy set rc=0 + pf-capture tests (D3D11VA pair, COM vtable); macOS `cargo check -p punktfunk-core` (MsghdrX — the only platform that compiles it).