Le sunnuntaina 2. lokakuuta 2022, 18.43.23 EEST Michael Niedermayer a écrit :
Fixes: signed integer overflow: 2040812214 + 255101526 cannot be represented in type 'int' Fixes: 51323/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_BONK_fuzzer-4791481 067503616
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> --- libavcodec/bonk.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/libavcodec/bonk.c b/libavcodec/bonk.c index 409694f710d..32f7c9b9bdb 100644 --- a/libavcodec/bonk.c +++ b/libavcodec/bonk.c @@ -187,6 +187,9 @@ static int intlist_read(BonkContext *s, int *buf, int entries, int base_2_part) if (!dominant) n_zeros += steplet;
+ if (step > INT_MAX/9*8) + return AVERROR_INVALIDDATA; + step += step / 8; } else if (steplet > 0) { int actual_run = read_uint_max(s, steplet - 1);
No problem with this patch *specifically* but wouldn't it be more effective to fix that sort of issue with checked arithmetic, e.g. something like: if (av_ckd_add(&step, step, step / 8)) return AVERROR_INVALIDDATA; ...especially on 64-bit systems whence this is really just an add. This also avoids having to figure out what the exact boundary value is. -- レミ・デニ-クールモン http://www.remlab.net/