[PATCH 3.16.y-ckt 185/185] lz4: fix system halt at boot kernel on x86_64

[Luis Henriques]

3.16.7-ckt15 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Krzysztof Kolasa <kkolasa at winsoft.pl>

commit 99b7e93c95c78952724a9783de6c78def8fbfc3f upstream.

Sometimes, on x86_64, decompression fails with the following
error:

Decompressing Linux...

Decoding failed

 -- System halted

This condition is not needed for a 64bit kernel(from commit d5e7caf):

if( ... ||
    (op + COPYLENGTH) > oend)
    goto _output_error

macro LZ4_SECURE_COPY() tests op and does not copy any data
when op exceeds the value.

added by analogy to lz4_uncompress_unknownoutputsize(...)

Signed-off-by: Krzysztof Kolasa <kkolasa at winsoft.pl>
Tested-by: Alexander Kuleshov <kuleshovmail at gmail.com>
Tested-by: Caleb Jorden <cjorden at gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 lib/lz4/lz4_decompress.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/lib/lz4/lz4_decompress.c b/lib/lz4/lz4_decompress.c
index f0f5c5c3de12..8a742b195c69 100644
--- a/lib/lz4/lz4_decompress.c
+++ b/lib/lz4/lz4_decompress.c
@@ -139,8 +139,12 @@ static int lz4_uncompress(const char *source, char *dest, int osize)
 			/* Error: request to write beyond destination buffer */
 			if (cpy > oend)
 				goto _output_error;
+#if LZ4_ARCH64
+			if ((ref + COPYLENGTH) > oend)
+#else
 			if ((ref + COPYLENGTH) > oend ||
 					(op + COPYLENGTH) > oend)
+#endif
 				goto _output_error;
 			LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
 			while (op < cpy)
@@ -270,7 +274,13 @@ static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
 		if (cpy > oend - COPYLENGTH) {
 			if (cpy > oend)
 				goto _output_error; /* write outside of buf */
-
+#if LZ4_ARCH64
+			if ((ref + COPYLENGTH) > oend)
+#else
+			if ((ref + COPYLENGTH) > oend ||
+					(op + COPYLENGTH) > oend)
+#endif
+				goto _output_error;
 			LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
 			while (op < cpy)
 				*op++ = *ref++;