From 39006dfef8b5b314209266cb0a65df11ad947417 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Thu, 21 Jan 2021 21:41:41 +0100 Subject: [PATCH] avformat/mxfdec: Fix integer overflow in next position in mxf_read_local_tags() Fixes: signed integer overflow: 9223372036854775723 + 8192 cannot be represented in type 'long' Fixes: 29072/clusterfuzz-testcase-minimized-ffmpeg_dem_MXF_fuzzer-4812604904177664 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit d3d9b1fc8e2dfc8b4d66c9916ab7221062ff4660) Signed-off-by: Michael Niedermayer --- libavformat/mxfdec.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c index 84b032ebde..ebbbbea2fb 100644 --- a/libavformat/mxfdec.c +++ b/libavformat/mxfdec.c @@ -2736,8 +2736,11 @@ static int mxf_read_local_tags(MXFContext *mxf, KLVPacket *klv, MXFMetadataReadF int ret; int tag = avio_rb16(pb); int size = avio_rb16(pb); /* KLV specified by 0x53 */ - uint64_t next = avio_tell(pb) + size; + int64_t next = avio_tell(pb); UID uid = {0}; + if (next < 0 || next > INT64_MAX - size) + return next < 0 ? next : AVERROR_INVALIDDATA; + next += size; av_log(mxf->fc, AV_LOG_TRACE, "local tag %#04x size %d\n", tag, size); if (!size) { /* ignore empty tag, needed for some files with empty UMID tag */