From 1b1dac2716d713dfd6949b7eb4a3c18c16f1faf6 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Mon, 9 Nov 2020 19:58:20 +0100 Subject: [PATCH] libavformat/utils: consider avio_size() failure in ffio_limit() Fixes: Timeout (>20sec -> 3ms) Fixes: 26918/clusterfuzz-testcase-minimized-ffmpeg_dem_THP_fuzzer-5750425191710720 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavformat/utils.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/libavformat/utils.c b/libavformat/utils.c index 8ac6bc04b8..f534b6e5b5 100644 --- a/libavformat/utils.c +++ b/libavformat/utils.c @@ -244,13 +244,16 @@ int av_format_get_probe_score(const AVFormatContext *s) int ffio_limit(AVIOContext *s, int size) { if (s->maxsize>= 0) { - int64_t remaining= s->maxsize - avio_tell(s); + int64_t pos = avio_tell(s); + int64_t remaining= s->maxsize - pos; if (remaining < size) { int64_t newsize = avio_size(s); if (!s->maxsize || s->maxsizemaxsize = newsize - !newsize; - remaining= s->maxsize - avio_tell(s); - remaining= FFMAX(remaining, 0); + if (pos > s->maxsize && s->maxsize >= 0) + s->maxsize = AVERROR(EIO); + if (s->maxsize >= 0) + remaining = s->maxsize - pos; } if (s->maxsize >= 0 && remaining < size && size > 1) {