[PATCH 3.14 59/68] lz4: ensure length does not wrap

Greg Kroah-Hartman
2014-06-24T16:18:41Z

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 206204a1162b995e2185275167b22468c00d6b36 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
lib/lz4/lz4_decompress.c | 2 ++
1 file changed, 2 insertions(+)

--- a/lib/lz4/lz4_decompress.c
+++ b/lib/lz4/lz4_decompress.c
@@ -72,6 +72,8 @@ static int lz4_uncompress(const char *so
len = *ip++;
for (; len == 255; length += 255)
len = *ip++;
+ if (unlikely(length > (size_t)(length + len)))
+ goto _output_error;
length += len;
}