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[FFmpeg-devel,5/5] avformat/mov: Fix last mfra check

Message ID 20210915200048.6691-5-michael@niedermayer.cc
State Accepted
Commit 451ceb5131fa67b0b380d4823981e421909c16db
Headers show
Series [FFmpeg-devel,1/5] avformat/sbgdec: Check for t0 overflow in expand_tseq() | expand

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Commit Message

Michael Niedermayer Sept. 15, 2021, 8 p.m. UTC 
Fixes: signed integer overflow: 9223372036854775360 + 536870912 cannot be represented in type 'long'
Fixes: 37940/clusterfuzz-testcase-minimized-ffmpeg_dem_MOV_fuzzer-6095637855207424

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavformat/mov.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Michael Niedermayer Sept. 26, 2021, 3:27 p.m. UTC | #1 
On Wed, Sep 15, 2021 at 10:00:48PM +0200, Michael Niedermayer wrote:
> Fixes: signed integer overflow: 9223372036854775360 + 536870912 cannot be represented in type 'long'
> Fixes: 37940/clusterfuzz-testcase-minimized-ffmpeg_dem_MOV_fuzzer-6095637855207424
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavformat/mov.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

will apply

[...]
diff mbox series

Patch

diff --git a/libavformat/mov.c b/libavformat/mov.c
index 4bc42d6b20e..d816242c0b7 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -5109,7 +5109,7 @@  static int mov_read_sidx(MOVContext *c, AVIOContext *pb, MOVAtom atom)
 
     // See if the remaining bytes are just an mfra which we can ignore.
     is_complete = offset == stream_size;
-    if (!is_complete && (pb->seekable & AVIO_SEEKABLE_NORMAL)) {
+    if (!is_complete && (pb->seekable & AVIO_SEEKABLE_NORMAL) && stream_size > 0 ) {
         int64_t ret;
         int64_t original_pos = avio_tell(pb);
         if (!c->have_read_mfra_size) {
@@ -5120,7 +5120,7 @@  static int mov_read_sidx(MOVContext *c, AVIOContext *pb, MOVAtom atom)
             if ((ret = avio_seek(pb, original_pos, SEEK_SET)) < 0)
                 return ret;
         }
-        if (offset + c->mfra_size == stream_size)
+        if (offset == stream_size - c->mfra_size)
             is_complete = 1;
     }