From: Michael Niedermayer <michael@niedermayer.cc>
Date: Sun, 4 Jun 2017 11:02:51 +0000 (+0200)
Subject: avcodec/ac3dec_fixed: Fix runtime error: left shift of 419 by 23 places cannot be... 
X-Git-Url: https://git.sesse.net/?a=commitdiff_plain;h=136ce8baa4fc16cf38690cb457f7356c00e00a28;p=ffmpeg

avcodec/ac3dec_fixed: Fix runtime error: left shift of 419 by 23 places cannot be represented in type 'int'

Fixes: 1352/clusterfuzz-testcase-minimized-5757565017260032

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/ac3dec_fixed.c b/libavcodec/ac3dec_fixed.c
index 682fe935b02..5a868e4abfe 100644
--- a/libavcodec/ac3dec_fixed.c
+++ b/libavcodec/ac3dec_fixed.c
@@ -69,7 +69,7 @@ static void scale_coefs (
     int temp, temp1, temp2, temp3, temp4, temp5, temp6, temp7;
 
     mul = (dynrng & 0x1f) + 0x20;
-    shift = 4 - ((dynrng << 23) >> 28);
+    shift = 4 - (sign_extend(dynrng, 9) >> 5);
     if (shift > 0 ) {
       round = 1 << (shift-1);
       for (i=0; i<len; i+=8) {