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[FFmpeg-devel,11/15] avformat/matroskadec: Check prebuffered_ns for overflow

Message ID 20230930223046.22896-11-michael@niedermayer.cc
State Accepted
Commit 2d6df3719dd4f75b40cdf25a02f3f075b76ed045
Headers show
Series [FFmpeg-devel,01/15] avformat/concatdec: Check in/outpoint for overflow | expand

Checks

Context Check Description
yinshiyou/make_fate_loongarch64 success Make fate finished
yinshiyou/make_loongarch64 warning New warnings during build
andriy/make_fate_x86 success Make fate finished
andriy/make_x86 warning New warnings during build

Commit Message

Michael Niedermayer Sept. 30, 2023, 10:30 p.m. UTC 
Fixes: signed integer overflow: 9223372036630775808 + 1000000000 cannot be represented in type 'long'
Fixes: 51896/clusterfuzz-testcase-minimized-ffmpeg_dem_WEBM_DASH_MANIFEST_fuzzer-5406131992526848

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavformat/matroskadec.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
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Patch

diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index 941c0bcdc9f..ae8823ae58e 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -4537,13 +4537,17 @@  static int64_t webm_dash_manifest_compute_bandwidth(AVFormatContext *s, int64_t
         int64_t prebuffer_ns = 1000000000;
         int64_t time_ns = sti->index_entries[i].timestamp * matroska->time_scale;
         double nano_seconds_per_second = 1000000000.0;
-        int64_t prebuffered_ns = time_ns + prebuffer_ns;
+        int64_t prebuffered_ns;
         double prebuffer_bytes = 0.0;
         int64_t temp_prebuffer_ns = prebuffer_ns;
         int64_t pre_bytes, pre_ns;
         double pre_sec, prebuffer, bits_per_second;
         CueDesc desc_beg = get_cue_desc(s, time_ns, cues_start);
 
+        if (time_ns > INT64_MAX - prebuffer_ns)
+            return -1;
+        prebuffered_ns = time_ns + prebuffer_ns;
+
         // Start with the first Cue.
         CueDesc desc_end = desc_beg;