[FFmpeg-cvslog] cafdec: fix overflow checking in read_header()

[Xi Wang]

ffmpeg | branch: master | Xi Wang <xi.wang at gmail.com> | Sun Jan 20 15:26:12 2013 -0500| [64b7e7dcaf21bd3c9f644446c59acdac6a95892f] | committer: Michael Niedermayer

cafdec: fix overflow checking in read_header()

Several compilers such as clang/icc/pathscale will optimize the check
pos + size < pos (assuming size > 0) into false, since signed integer
overflow is undefined behavior in C.  This breaks overflow checking.
Use a safe precondition check instead.

Signed-off-by: Xi Wang <xi.wang at gmail.com>
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=64b7e7dcaf21bd3c9f644446c59acdac6a95892f
---

 libavformat/cafdec.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/cafdec.c b/libavformat/cafdec.c
index f12226a..337758e 100644
--- a/libavformat/cafdec.c
+++ b/libavformat/cafdec.c
@@ -300,7 +300,7 @@ static int read_header(AVFormatContext *s)
         }
 
         if (size > 0) {
-            if (pos + size < pos)
+            if (pos > INT64_MAX - size)
                 return AVERROR_INVALIDDATA;
             avio_skip(pb, FFMAX(0, pos + size - avio_tell(pb)));
         }