From 0c56afb8d6c28d98ed9d4d373d6461c0921ac382 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 17 Sep 2022 21:30:55 +0200 Subject: [PATCH] avformat/asfdec_o: Limit packet offset avoids overflows with it Fixes: signed integer overflow: 9223372036846866010 + 4294967047 cannot be represented in type 'long' Fixes: 50993/clusterfuzz-testcase-minimized-ffmpeg_dem_ASF_O_fuzzer-6538296768987136 Fixes: 50993/clusterfuzz-testcase-minimized-ffmpeg_dem_ASF_O_fuzzer-657169555665715 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit 736e9e69d5dbbe1d81885dfef59917eb915d2f96) Signed-off-by: Michael Niedermayer --- libavformat/asfdec_o.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/libavformat/asfdec_o.c b/libavformat/asfdec_o.c index baede5ba20..71e65f4763 100644 --- a/libavformat/asfdec_o.c +++ b/libavformat/asfdec_o.c @@ -1361,6 +1361,8 @@ static int asf_read_packet_header(AVFormatContext *s) unsigned char error_flags, len_flags, pay_flags; asf->packet_offset = avio_tell(pb); + if (asf->packet_offset > INT64_MAX/2) + asf->packet_offset = 0; error_flags = avio_r8(pb); // read Error Correction Flags if (error_flags & ASF_PACKET_FLAG_ERROR_CORRECTION_PRESENT) { if (!(error_flags & ASF_ERROR_CORRECTION_LENGTH_TYPE)) {