[FFmpeg-devel] [PATCH 3/3] avcodec/diracdec: Fix integer overflow in mv computation

Michael Niedermayer michael at niedermayer.cc
Mon Feb 19 00:07:22 EET 2018


Fixes: signed integer overflow: -2072 + -2147483646 cannot be represented in type 'int'
Fixes: 6097/clusterfuzz-testcase-minimized-5034145253163008

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

diff --git a/libavcodec/diracdec.c b/libavcodec/diracdec.c
index e3afbf14be..753adeff61 100644
--- a/libavcodec/diracdec.c
+++ b/libavcodec/diracdec.c
@@ -1437,8 +1437,8 @@ static void decode_block_params(DiracContext *s, DiracArith arith[8], DiracBlock
                 global_mv(s, block, x, y, i);
             } else {
                 pred_mv(block, stride, x, y, i);
-                block->u.mv[i][0] += dirac_get_arith_int(arith + 4 + 2 * i, CTX_MV_F1, CTX_MV_DATA);
-                block->u.mv[i][1] += dirac_get_arith_int(arith + 5 + 2 * i, CTX_MV_F1, CTX_MV_DATA);
+                block->u.mv[i][0] += (unsigned)dirac_get_arith_int(arith + 4 + 2 * i, CTX_MV_F1, CTX_MV_DATA);
+                block->u.mv[i][1] += (unsigned)dirac_get_arith_int(arith + 5 + 2 * i, CTX_MV_F1, CTX_MV_DATA);
             }
         }
 }
-- 
2.16.1



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