[FFmpeg-devel] avcodec/diracdec: Fix integer overflow in global_mv()

Submitted by Michael Niedermayer on May 22, 2019, 12:35 a.m.

Details

Message ID 20190522003546.31086-1-michael@niedermayer.cc
State Accepted
Commit a99ffb5bb4454c625748972d9389cfaa5433a342
Headers show

Commit Message

Michael Niedermayer May 22, 2019, 12:35 a.m.
Fixes: signed integer overflow: 16384 * 196607 cannot be represented in type 'int'
Fixes: 14810/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_DIRAC_fuzzer-5091232683917312

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

Comments

Michael Niedermayer June 5, 2019, 11:05 a.m.
On Wed, May 22, 2019 at 02:35:46AM +0200, Michael Niedermayer wrote:
> Fixes: signed integer overflow: 16384 * 196607 cannot be represented in type 'int'
> Fixes: 14810/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_DIRAC_fuzzer-5091232683917312
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavcodec/diracdec.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

will apply

[...]

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diff --git a/libavcodec/diracdec.c b/libavcodec/diracdec.c
index a5bb6d5f34..643e3a7753 100644
--- a/libavcodec/diracdec.c
+++ b/libavcodec/diracdec.c
@@ -1433,8 +1433,8 @@  static void global_mv(DiracContext *s, DiracBlock *block, int x, int y, int ref)
     int *c      = s->globalmc[ref].perspective;
 
     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]);
+    int64_t mx  = m * (int64_t)((A[0][0] * (int64_t)x + A[0][1]*(int64_t)y) + (1LL<<ez) * b[0]);
+    int64_t my  = m * (int64_t)((A[1][0] * (int64_t)x + A[1][1]*(int64_t)y) + (1LL<<ez) * b[1]);
 
     block->u.mv[ref][0] = (mx + (1<<(ez+ep))) >> (ez+ep);
     block->u.mv[ref][1] = (my + (1<<(ez+ep))) >> (ez+ep);