From 2ef522c918d48b9f101548b2cadce02003cb3510 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 23 Jan 2021 22:00:40 +0100 Subject: [PATCH] avformat/flvdec: Check for nesting depth in amf_skip_tag() Fixes: out of array access Fixes: 29440/clusterfuzz-testcase-minimized-ffmpeg_dem_KUX_fuzzer-5985279812960256.fuzz Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavformat/flvdec.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c index 5e4af8eca4..8571a626ae 100644 --- a/libavformat/flvdec.c +++ b/libavformat/flvdec.c @@ -842,10 +842,13 @@ static void clear_index_entries(AVFormatContext *s, int64_t pos) } } -static int amf_skip_tag(AVIOContext *pb, AMFDataType type) +static int amf_skip_tag(AVIOContext *pb, AMFDataType type, int depth) { int nb = -1, ret, parse_name = 1; + if (depth > MAX_DEPTH) + return AVERROR_PATCHWELCOME; + switch (type) { case AMF_DATA_TYPE_NUMBER: avio_skip(pb, 8); @@ -870,7 +873,7 @@ static int amf_skip_tag(AVIOContext *pb, AMFDataType type) } avio_skip(pb, size); } - if ((ret = amf_skip_tag(pb, avio_r8(pb))) < 0) + if ((ret = amf_skip_tag(pb, avio_r8(pb), depth + 1)) < 0) return ret; } break; @@ -914,7 +917,7 @@ static int flv_data_packet(AVFormatContext *s, AVPacket *pkt, else break; } else { - if ((ret = amf_skip_tag(pb, type)) < 0) + if ((ret = amf_skip_tag(pb, type, 0)) < 0) goto skip; } }