avcodec/aacdec_fixed: fix invalid shift in predict()
authorMichael Niedermayer <michael@niedermayer.cc>
Fri, 4 Aug 2017 01:26:30 +0000 (03:26 +0200)
committerMichael Niedermayer <michael@niedermayer.cc>
Sat, 9 Sep 2017 23:33:28 +0000 (01:33 +0200)
Fixes: runtime error: shift exponent -2 is negative
Fixes: 2818/clusterfuzz-testcase-minimized-5062943676825600

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 1e443051b277f73b94a2f660d3fd31a1a7beab52)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
libavcodec/aacdec_fixed.c

index ccc8205..e7c2d2d 100644 (file)
@@ -305,8 +305,12 @@ static av_always_inline void predict(PredictorState *ps, int *coef,
     if (output_enable) {
         int shift = 28 - pv.exp;
 
-        if (shift < 31)
-            *coef += (pv.mant + (1 << (shift - 1))) >> shift;
+        if (shift < 31) {
+            if (shift > 0) {
+                *coef += (pv.mant + (1 << (shift - 1))) >> shift;
+            } else
+                *coef += pv.mant << -shift;
+        }
     }
 
     e0 = av_int2sf(*coef, 2);