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| author | Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> | 2015-03-05 22:48:28 +0100 |
|---|---|---|
| committer | Michael Niedermayer <michaelni@gmx.at> | 2015-03-21 01:52:52 +0100 |
| commit | 57c7922331d5f2c0999046845bd9bf24ac74c2b7 (patch) | |
| tree | efd7811c9eab906dfa3c85e63456196b25af0c26 | |
| parent | 73dd8f0a2431851d99f3a94acfd608a2e820b6ab (diff) | |
| download | ffmpeg-57c7922331d5f2c0999046845bd9bf24ac74c2b7.tar.gz | |
webp: ensure that each transform is only used once
According to the WebP Lossless Bitstream Specification
"each transform is allowed to be used only once".
If a transform is more than once this can lead to memory
corruption.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit c089e720c1b753790c746a13053636d7facf6bf0)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
| -rw-r--r-- | libavcodec/webp.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/libavcodec/webp.c b/libavcodec/webp.c index 4b1c8e7f8b..802b03c826 100644 --- a/libavcodec/webp.c +++ b/libavcodec/webp.c @@ -1099,7 +1099,7 @@ static int vp8_lossless_decode_frame(AVCodecContext *avctx, AVFrame *p, unsigned int data_size, int is_alpha_chunk) { WebPContext *s = avctx->priv_data; - int w, h, ret, i; + int w, h, ret, i, used; if (!is_alpha_chunk) { s->lossless = 1; @@ -1149,8 +1149,16 @@ static int vp8_lossless_decode_frame(AVCodecContext *avctx, AVFrame *p, /* parse transformations */ s->nb_transforms = 0; s->reduced_width = 0; + used = 0; while (get_bits1(&s->gb)) { enum TransformType transform = get_bits(&s->gb, 2); + if (used & (1 << transform)) { + av_log(avctx, AV_LOG_ERROR, "Transform %d used more than once\n", + transform); + ret = AVERROR_INVALIDDATA; + goto free_and_return; + } + used |= (1 << transform); s->transforms[s->nb_transforms++] = transform; switch (transform) { case PREDICTOR_TRANSFORM: |