avcodec/mpeg4videodec: Check sprite delta upshift against overflowing.
authorMichael Niedermayer <michael@niedermayer.cc>
Wed, 14 Jun 2017 21:55:17 +0000 (23:55 +0200)
committerMichael Niedermayer <michael@niedermayer.cc>
Wed, 14 Jun 2017 22:16:20 +0000 (00:16 +0200)
Fixes: runtime error: signed integer overflow: -268386304 * 16 cannot be represented in type 'int'
Fixes: 2204/clusterfuzz-testcase-minimized-5616756909408256

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
libavcodec/mpeg4videodec.c

index 3edf266..99680da 100644 (file)
@@ -361,14 +361,16 @@ static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *g
         int shift_y = 16 - ctx->sprite_shift[0];
         int shift_c = 16 - ctx->sprite_shift[1];
 
-        if (shift_c < 0 || shift_y < 0 ||
-            FFABS(sprite_offset[0][0]) >= INT_MAX >> shift_y  ||
-            FFABS(sprite_offset[1][0]) >= INT_MAX >> shift_c  ||
-            FFABS(sprite_offset[0][1]) >= INT_MAX >> shift_y  ||
-            FFABS(sprite_offset[1][1]) >= INT_MAX >> shift_c
-        ) {
-            avpriv_request_sample(s->avctx, "Too large sprite shift or offset");
-            goto overflow;
+        for (i = 0; i < 2; i++) {
+            if (shift_c < 0 || shift_y < 0 ||
+                FFABS(  sprite_offset[0][i]) >= INT_MAX >> shift_y  ||
+                FFABS(  sprite_offset[1][i]) >= INT_MAX >> shift_c  ||
+                FFABS(s->sprite_delta[0][i]) >= INT_MAX >> shift_y  ||
+                FFABS(s->sprite_delta[1][i]) >= INT_MAX >> shift_y
+            ) {
+                avpriv_request_sample(s->avctx, "Too large sprite shift, delta or offset");
+                goto overflow;
+            }
         }
 
         for (i = 0; i < 2; i++) {