From 738b829b8cdf079a5fa48c74a28a177c9567d212 Mon Sep 17 00:00:00 2001
From: Johann <johannkoenig@google.com>
Date: Fri, 26 Jan 2018 15:50:50 -0800
Subject: [PATCH] Fix incorrect size reading

Cherry pick from vp9:

commit 85770264ac891505730dcd5092d1993a62c74060
Guard against incorrect size values moving *data past data_end.

Check read length against the difference of the buffers.

Change-Id: I5e8679ddd447c4d73deb80be5ec94841a92c5fcd
---
 vp8/decoder/decodeframe.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/vp8/decoder/decodeframe.c b/vp8/decoder/decodeframe.c
index 077bd3da2..c208f6141 100644
--- a/vp8/decoder/decodeframe.c
+++ b/vp8/decoder/decodeframe.c
@@ -674,7 +674,7 @@ static unsigned int read_partition_size(VP8D_COMP *pbi,
 
 static int read_is_valid(const unsigned char *start, size_t len,
                          const unsigned char *end) {
-  return (start + len > start && start + len <= end);
+  return len != 0 && len <= (size_t)(end - start);
 }
 
 static unsigned int read_available_partition_size(