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| author | Michael Niedermayer <michaelni@gmx.at> | 2014-10-03 20:15:52 +0200 |
|---|---|---|
| committer | Anton Khirnov <anton@khirnov.net> | 2014-12-19 08:01:47 +0100 |
| commit | 0b39ac6f54505a538c21fe49a626de94c518c903 (patch) | |
| tree | d66a98d217c4b5e5ba58591a7d1131d78ae9563f | |
| parent | 17ba719d9ba30c970f65747f42d5fbb1e447ca28 (diff) | |
| download | ffmpeg-0b39ac6f54505a538c21fe49a626de94c518c903.tar.gz | |
gifdec: refactor interleave end handling
Fixes invalid writes with very small image heights.
CC: libav-stable@libav.org
Bug-ID: CVE-2014-8547
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Anton Khirnov <anton@khirnov.net>
| -rw-r--r-- | libavcodec/gifdec.c | 15 |
1 files changed, 5 insertions, 10 deletions
diff --git a/libavcodec/gifdec.c b/libavcodec/gifdec.c index cdb7f23fd4..df5ab78aba 100644 --- a/libavcodec/gifdec.c +++ b/libavcodec/gifdec.c @@ -125,26 +125,21 @@ static int gif_read_image(GifState *s, AVFrame *frame) case 1: y1 += 8; ptr += linesize * 8; - if (y1 >= height) { - y1 = pass ? 2 : 4; - ptr = ptr1 + linesize * y1; - pass++; - } break; case 2: y1 += 4; ptr += linesize * 4; - if (y1 >= height) { - y1 = 1; - ptr = ptr1 + linesize; - pass++; - } break; case 3: y1 += 2; ptr += linesize * 2; break; } + while (y1 >= height) { + y1 = 4 >> pass; + ptr = ptr1 + linesize * y1; + pass++; + } } else { ptr += linesize; } |