From d8ee01425459aaafe36acc7743b3f9f28a01821b Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Thu, 16 Jun 2022 23:02:11 +0200 Subject: avformat/hls: Limit start_seq_no to one bit less This avoids overflow checks on additions with 32bit numbers Fixes: signed integer overflow: 9223372036854775806 + 2 cannot be represented in type 'long' Fixes: 44012/clusterfuzz-testcase-minimized-ffmpeg_dem_HLS_fuzzer-4747770734444544 Fixes: 48065/clusterfuzz-testcase-minimized-ffmpeg_dem_HLS_fuzzer-5372410355908608 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavformat/hls.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'libavformat') diff --git a/libavformat/hls.c b/libavformat/hls.c index 8204f55df3..b736f093a9 100644 --- a/libavformat/hls.c +++ b/libavformat/hls.c @@ -837,10 +837,10 @@ static int parse_playlist(HLSContext *c, const char *url, if (ret < 0) goto fail; seq_no = strtoull(ptr, NULL, 10); - if (seq_no > INT64_MAX) { + if (seq_no > INT64_MAX/2) { av_log(c->ctx, AV_LOG_DEBUG, "MEDIA-SEQUENCE higher than " - "INT64_MAX, mask out the highest bit\n"); - seq_no &= INT64_MAX; + "INT64_MAX/2, mask out the highest bit\n"); + seq_no &= INT64_MAX/2; } pls->start_seq_no = seq_no; } else if (av_strstart(line, "#EXT-X-PLAYLIST-TYPE:", &ptr)) { -- cgit v1.2.3