avcodec/diracdec: Fix integer overflow in global_mv()

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>

diff --git a/libavcodec/diracdec.c b/libavcodec/diracdec.c
index 52a19516901229e0e0fe39648ea5af8fec020729..7b9e0099dfc992afba5d1ab9f6d6d2356951aef0 100644 (file)
--- 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);