From c8140fe7324f264faacf7395b27e12531d1f13f7 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sun, 15 Mar 2020 17:26:51 +0100 Subject: [PATCH] avformat/asfdec_f: Fix overflow check in get_tag() Fixes: signed integer overflow: 2 * 1210064928 cannot be represented in type 'int' Fixes: 20873/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5761116909338624 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Reviewed-by: Anton Khirnov Signed-off-by: Michael Niedermayer --- libavformat/asfdec_f.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/libavformat/asfdec_f.c b/libavformat/asfdec_f.c index 57dc3b09b9..f0cb353587 100644 --- a/libavformat/asfdec_f.c +++ b/libavformat/asfdec_f.c @@ -321,8 +321,7 @@ static void get_tag(AVFormatContext *s, const char *key, int type, int len, int int64_t off = avio_tell(s->pb); #define LEN 22 - if ((unsigned)len >= (UINT_MAX - LEN) / 2) - return; + av_assert0((unsigned)len < (INT_MAX - LEN) / 2); if (!asf->export_xmp && !strncmp(key, "xmp", 3)) goto finish; @@ -712,6 +711,9 @@ static int asf_read_metadata(AVFormatContext *s, int64_t size) value_type = avio_rl16(pb); /* value_type */ value_len = avio_rl32(pb); + if (value_len < 0 || value_len > UINT16_MAX) + return AVERROR_INVALIDDATA; + name_len_utf8 = 2*name_len_utf16 + 1; name = av_malloc(name_len_utf8); if (!name) @@ -857,11 +859,20 @@ static int asf_read_header(AVFormatContext *s) return ret; av_hex_dump_log(s, AV_LOG_DEBUG, pkt.data, pkt.size); av_packet_unref(&pkt); + len= avio_rl32(pb); + if (len > UINT16_MAX) + return AVERROR_INVALIDDATA; get_tag(s, "ASF_Protection_Type", -1, len, 32); + len= avio_rl32(pb); + if (len > UINT16_MAX) + return AVERROR_INVALIDDATA; get_tag(s, "ASF_Key_ID", -1, len, 32); + len= avio_rl32(pb); + if (len > UINT16_MAX) + return AVERROR_INVALIDDATA; get_tag(s, "ASF_License_URL", -1, len, 32); } else if (!ff_guidcmp(&g, &ff_asf_ext_content_encryption)) { av_log(s, AV_LOG_WARNING,