avcodec/diracdec: Fix integer overflow with quant
authorMichael Niedermayer <michael@niedermayer.cc>
Sun, 7 Jan 2018 19:43:24 +0000 (20:43 +0100)
committerMichael Niedermayer <michael@niedermayer.cc>
Mon, 19 Feb 2018 01:40:54 +0000 (02:40 +0100)
Fixes: signed integer overflow: 2 + 2147483646 cannot be represented in type 'int'
Fixes: 4792/clusterfuzz-testcase-minimized-6322450775146496

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit eaa93175895568ef6c2542b13104874907d9c4ef)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
libavcodec/diracdec.c

index 69ff083..2cdebe8 100644 (file)
@@ -516,16 +516,16 @@ static inline void codeblock(DiracContext *s, SubBand *b,
     }
 
     if (s->codeblock_mode && !(s->old_delta_quant && blockcnt_one)) {
-        int quant = b->quant;
+        int quant;
         if (is_arith)
-            quant += dirac_get_arith_int(c, CTX_DELTA_Q_F, CTX_DELTA_Q_DATA);
+            quant = dirac_get_arith_int(c, CTX_DELTA_Q_F, CTX_DELTA_Q_DATA);
         else
-            quant += dirac_get_se_golomb(gb);
-        if (quant < 0) {
+            quant = dirac_get_se_golomb(gb);
+        if (quant > INT_MAX - b->quant || b->quant + quant < 0) {
             av_log(s->avctx, AV_LOG_ERROR, "Invalid quant\n");
             return;
         }
-        b->quant = quant;
+        b->quant += quant;
     }
 
     if (b->quant > 115) {