On 4/4/2021 6:44 PM, Michael Niedermayer wrote:
Fixes: Invalid read of size 4
Fixes: ASAN_Deadlysignal.zip
Found-by: Hardik Shah <hardi...@gmail.com>
Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc>
---
libavformat/mov.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/libavformat/mov.c b/libavformat/mov.c
index 7805330bf9..ef73f3199d 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -7161,6 +7161,8 @@ static int mov_probe(const AVProbeData *p)
score = FFMAX(score, AVPROBE_SCORE_EXTENSION);
break;
}
+ if ((uint64_t)size + 8 > INT64_MAX - offset)
+ break;
offset += size;
}
if (score > AVPROBE_SCORE_MAX - 50 && moov_offset != -1) {
Would something like this also work?
diff --git a/libavformat/mov.c b/libavformat/mov.c
index 1974498d1e..cd9d9996b3 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -7119,7 +7119,7 @@ static int mov_probe(const AVProbeData *p)
int64_t size;
int minsize = 8;
/* ignore invalid offset */
- if ((offset + 8) > (unsigned int)p->buf_size)
+ if ((offset + 8ULL) > (unsigned int)p->buf_size)
break;
size = AV_RB32(p->buf + offset);
if (size == 1 && offset + 16 <= (unsigned int)p->buf_size) {
@@ -7166,6 +7166,8 @@ static int mov_probe(const AVProbeData *p)
score = FFMAX(score, AVPROBE_SCORE_EXTENSION);
break;
}
+ if (size > INT64_MAX - offset)
+ break;
offset += size;
}
if (score > AVPROBE_SCORE_MAX - 50 && moov_offset != -1) {
I think it conveys what it's trying to do more clearly than your
version, where the + 8 on top of size is not immediately clear where it
comes from.
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