From 9739a269fb4d94b93ebcae31cd11d61b68407633 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka-at-google.com@ffmpeg.org>
Date: Sun, 20 Aug 2017 11:56:47 -0700
Subject: [PATCH] avformat/aviobuf: Fix signed integer overflow in avio_seek()

Signed integer overflow is undefined behavior.
Detected with clang and -fsanitize=signed-integer-overflow

Signed-off-by: Vitaly Buka <vitalybuka@google.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit eca2a49716ae1f42804dd3545da2f740edf03250)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavformat/aviobuf.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
index ef6a0d4e9b..9afe9b3a68 100644
--- a/libavformat/aviobuf.c
+++ b/libavformat/aviobuf.c
@@ -251,6 +251,8 @@ int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
         offset1 = pos + (s->buf_ptr - s->buffer);
         if (offset == 0)
             return offset1;
+        if (offset > INT64_MAX - offset1)
+            return AVERROR(EINVAL);
         offset += offset1;
     }
     if (offset < 0)