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[FFmpeg-devel] avcodec/diracdec: Use 64bit in intermediate of global motion vector field generation

Message ID 20190407153236.30646-1-michael@niedermayer.cc
State Accepted
Commit 837820f385af699f9bee5e2ba3169dda15e5894d
Headers show

Commit Message

Michael Niedermayer April 7, 2019, 3:32 p.m. UTC 
It seems the specification does not limit the value to 32bit

Fixes: signed integer overflow: -109611143 * 24 cannot be represented in type 'int'
Fixes: 13477/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_DIRAC_fuzzer-5648337460527104

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/diracdec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Michael Niedermayer April 19, 2019, 6:05 p.m. UTC | #1 
On Sun, Apr 07, 2019 at 05:32:36PM +0200, Michael Niedermayer wrote:
> It seems the specification does not limit the value to 32bit
> 
> Fixes: signed integer overflow: -109611143 * 24 cannot be represented in type 'int'
> Fixes: 13477/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_DIRAC_fuzzer-5648337460527104
> 
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavcodec/diracdec.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

will apply


[...]
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Patch

diff --git a/libavcodec/diracdec.c b/libavcodec/diracdec.c
index a1e759f656..a5bb6d5f34 100644
--- a/libavcodec/diracdec.c
+++ b/libavcodec/diracdec.c
@@ -1432,7 +1432,7 @@  static void global_mv(DiracContext *s, DiracBlock *block, int x, int y, int ref)
     int *b      = s->globalmc[ref].pan_tilt;
     int *c      = s->globalmc[ref].perspective;
 
-    int m       = (1<<ep) - (c[0]*x + c[1]*y);
+    int64_t m   = (1<<ep) - (c[0]*(int64_t)x + c[1]*(int64_t)y);
     int64_t mx  = m * (int64_t)((A[0][0] * (int64_t)x + A[0][1]*(int64_t)y) + (1<<ez) * b[0]);
     int64_t my  = m * (int64_t)((A[1][0] * (int64_t)x + A[1][1]*(int64_t)y) + (1<<ez) * b[1]);