On 9/29/2023 8:19 PM, Michael Niedermayer wrote:
Fixes: signed integer overflow: 64 + 9223372036854775803 cannot be represented
in type 'long long'
Fixes:
51896/clusterfuzz-testcase-minimized-ffmpeg_dem_CAF_fuzzer-6536881135550464
Found-by: continuous fuzzing process
https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc>
---
libavformat/cafdec.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libavformat/cafdec.c b/libavformat/cafdec.c
index e92e3279fc6..0e50a3cfe68 100644
--- a/libavformat/cafdec.c
+++ b/libavformat/cafdec.c
@@ -435,7 +435,7 @@ static int read_packet(AVFormatContext *s, AVPacket *pkt)
/* don't read past end of data chunk */
if (caf->data_size > 0) {
- left = (caf->data_start + caf->data_size) - avio_tell(pb);
+ left = av_sat_add64(caf->data_start, caf->data_size) - avio_tell(pb);
avio_tell(pb) here is guaranteed to be bigger than caf->data_start,
which is the offset where the DATA chunk starts, so the result of this
calculation will be <= INT64_MAX even if you don't saturate it and
instead cast it to uint64_t. Nonetheless, if the DATA chunk ends at an
offset that would not fit in an int64_t, then we can't parse it to begin
with due to AVIOContext API limitations.
Maybe we should just abort in read_header() if data_start + data_size >
INT64_MAX, instead of pretending we can parse the file, invalid or not,
by saturating values.
if (!left)
return AVERROR_EOF;
if (left < 0)
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