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mux,anim: ensure all images are in ANMF chunks

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In an animated file, all image chunks must be contained in ANMF chunks.
This fixes an assertion failure:

```
src/mux/muxedit.c:448 in WebPMuxError
  GetAdjustedCanvasSize(const WebPMux *const, int *const, int *const):
  wpi->header != NULL
```

The demux library already has this check.

Bug: 498966755
Change-Id: I1f04088a60326b47d26d7690277192118ed8374f
This commit is contained in:
James Zern
2026-04-07 13:06:13 -07:00
parent 6a9eb44282
commit c95ed44524
1 changed files with 12 additions and 9 deletions
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21
src/mux/muxinternal.c
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@@ -500,6 +500,14 @@ WebPMuxError MuxValidate(const WebPMux* const mux) {
err = ValidateChunk(mux, IDX_XMP, XMP_FLAG, flags, 1, &num_xmp);
if (err != WEBP_MUX_OK) return err;
// Verify either VP8X chunk is present OR there is only one elem in
// mux->images.
err = ValidateChunk(mux, IDX_VP8X, NO_FLAG, flags, 1, &num_vp8x);
if (err != WEBP_MUX_OK) return err;
err = ValidateChunk(mux, IDX_VP8, NO_FLAG, flags, -1, &num_images);
if (err != WEBP_MUX_OK) return err;
if (num_vp8x == 0 && num_images != 1) return WEBP_MUX_INVALID_ARGUMENT;
// Animation: ANIMATION_FLAG, ANIM chunk and ANMF chunk(s) are consistent.
// At most one ANIM chunk.
err = ValidateChunk(mux, IDX_ANIM, NO_FLAG, flags, 1, &num_anim);
@@ -509,7 +517,10 @@ WebPMuxError MuxValidate(const WebPMux* const mux) {
{
const int has_animation = !!(flags & ANIMATION_FLAG);
if (has_animation && (num_anim == 0 || num_frames == 0)) {
// An ANIM chunk must be present when has_animation is true, and all images
// must be contained in ANMF chunks.
if (has_animation &&
(num_anim == 0 || num_frames == 0 || num_frames != num_images)) {
return WEBP_MUX_INVALID_ARGUMENT;
}
if (!has_animation && (num_anim == 1 || num_frames > 0)) {
@@ -531,14 +542,6 @@ WebPMuxError MuxValidate(const WebPMux* const mux) {
}
}
// Verify either VP8X chunk is present OR there is only one elem in
// mux->images.
err = ValidateChunk(mux, IDX_VP8X, NO_FLAG, flags, 1, &num_vp8x);
if (err != WEBP_MUX_OK) return err;
err = ValidateChunk(mux, IDX_VP8, NO_FLAG, flags, -1, &num_images);
if (err != WEBP_MUX_OK) return err;
if (num_vp8x == 0 && num_images != 1) return WEBP_MUX_INVALID_ARGUMENT;
// ALPHA_FLAG & alpha chunk(s) are consistent.
// Note: ALPHA_FLAG can be set when there is actually no Alpha data present.
if (MuxHasAlpha(mux->images)) {