From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Sat, 21 Jun 2014 05:01:41 +0000 (-0700)
Subject: lz4: ensure length does not wrap
X-Git-Tag: v3.16-rc3~11^2~1
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=206204a1162b995e2185275167b22468c00d6b36;p=platform%2Fkernel%2Flinux-exynos.git

lz4: ensure length does not wrap

Given some pathologically compressed data, lz4 could possibly decide to
wrap a few internal variables, causing unknown things to happen.  Catch
this before the wrapping happens and abort the decompression.

Reported-by: "Don A. Bailey" <donb@securitymouse.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/lib/lz4/lz4_decompress.c b/lib/lz4/lz4_decompress.c
index df6839e..99a03ac 100644
--- a/lib/lz4/lz4_decompress.c
+++ b/lib/lz4/lz4_decompress.c
@@ -72,6 +72,8 @@ static int lz4_uncompress(const char *source, char *dest, int osize)
 			len = *ip++;
 			for (; len == 255; length += 255)
 				len = *ip++;
+			if (unlikely(length > (size_t)(length + len)))
+				goto _output_error;
 			length += len;
 		}