From 9c84c162e9f9f000ef47d4fcd07354805f38d455 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Mon, 9 Sep 2019 20:05:09 +0200 Subject: avcodec/g2meet: Check if adjusted pixel was on the stack This basically checks if a pixel that was coded with prediction and residual could have been stored using a previous case. This avoids basically a string of 0 symbols stored in less than 50 bytes to hit a O(n²) codepath. Fixes: Timeout (too slow to wait -> immediately) Fixes: 8668/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_G2M_fuzzer-4895946310680576 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/g2meet.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/libavcodec/g2meet.c b/libavcodec/g2meet.c index a1dec8d823..19e1c130ce 100644 --- a/libavcodec/g2meet.c +++ b/libavcodec/g2meet.c @@ -854,6 +854,9 @@ static int epic_decode_tile(ePICContext *dc, uint8_t *out, int tile_height, uint32_t ref_pix = curr_row[x - 1]; if (!x || !epic_decode_from_cache(dc, ref_pix, &pix)) { pix = epic_decode_pixel_pred(dc, x, y, curr_row, above_row); + if (is_pixel_on_stack(dc, pix)) + return AVERROR_INVALIDDATA; + if (x) { int ret = epic_add_pixel_to_cache(&dc->hash, ref_pix, -- cgit v1.2.3