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| author | Michael Niedermayer <michael@niedermayer.cc> | 2022-11-22 21:54:51 +0100 |
|---|---|---|
| committer | Michael Niedermayer <michael@niedermayer.cc> | 2022-11-28 21:20:56 +0100 |
| commit | 1fdb65d2b7e23d042c211f1afe5e673233fd24c6 (patch) | |
| tree | 41756ac65c0d1b0764cd2089d71e86dc887fdf40 | |
| parent | 5185d5656b5fc37541606a804f831e08e434baab (diff) | |
| download | ffmpeg-1fdb65d2b7e23d042c211f1afe5e673233fd24c6.tar.gz | |
avcodec/pictordec: Check that the image fits in the input
Fixes: Timeout
Fixes: 53438/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_PICTOR_fuzzer-5458939919859712
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpe
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
| -rw-r--r-- | libavcodec/pictordec.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/libavcodec/pictordec.c b/libavcodec/pictordec.c index 71bad40a0a..1c07aa98f4 100644 --- a/libavcodec/pictordec.c +++ b/libavcodec/pictordec.c @@ -162,6 +162,25 @@ static int decode_frame(AVCodecContext *avctx, AVFrame *frame, if (av_image_check_size(s->width, s->height, 0, avctx) < 0) return -1; + + /* + There are 2 coding modes, RLE and RAW. + Undamaged RAW should be proportional to W*H and thus bigger than RLE + RLE codes the most compressed runs by + 1 byte for val (=marker) + 1 byte run (=0) + 2 bytes run + 1 byte val + thats 5 bytes and the maximum run we can code is 65535 + + The RLE decoder can exit prematurly but it does not on any image available + Based on this the formula is assumed correct for undamaged images. + If an image is found which exploits the special end + handling and breaks this formula then this needs to be adapted. + */ + if (bytestream2_get_bytes_left(&s->g) < s->width * s->height / 65535 * 5) + return AVERROR_INVALIDDATA; + if (s->width != avctx->width || s->height != avctx->height) { ret = ff_set_dimensions(avctx, s->width, s->height); if (ret < 0) |