[3.16.y-ckt stable] Patch "lz4: fix system halt at boot kernel on x86_64" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    lz4: fix system halt at boot kernel on x86_64

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt15.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 162831b1fb2311627eb5e23b99d1c95308979718 Mon Sep 17 00:00:00 2001
From: Krzysztof Kolasa <kkolasa at winsoft.pl>
Date: Sun, 3 May 2015 22:58:59 -0500
Subject: lz4: fix system halt at boot kernel on x86_64

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++;