[libav-stable] lavf: avoid integer overflow when estimating bitrate

Anton Khirnov git at libav.org
Mon Sep 2 19:48:43 CEST 2013


Module: libav
Branch: master
Commit: df33a58e5311ee9a64a573889b883a80e981af7b

Author:    Anton Khirnov <anton at khirnov.net>
Committer: Anton Khirnov <anton at khirnov.net>
Date:      Sat Aug 24 21:30:46 2013 +0200

lavf: avoid integer overflow when estimating bitrate

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable at libav.org

---

 libavformat/utils.c |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/libavformat/utils.c b/libavformat/utils.c
index eb89f43..3644bcd 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -1757,8 +1757,13 @@ static void estimate_timings_from_bit_rate(AVFormatContext *ic)
         int bit_rate = 0;
         for(i=0;i<ic->nb_streams;i++) {
             st = ic->streams[i];
-            if (st->codec->bit_rate > 0)
-            bit_rate += st->codec->bit_rate;
+            if (st->codec->bit_rate > 0) {
+                if (INT_MAX - st->codec->bit_rate > bit_rate) {
+                    bit_rate = 0;
+                    break;
+                }
+                bit_rate += st->codec->bit_rate;
+            }
         }
         ic->bit_rate = bit_rate;
     }



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