[038/141] cifs: fix potential buffer overrun when composing a new options string

Steven Rostedt
2013-07-03T18:54:30Z

[-- Attachment #1: 0038-cifs-fix-potential-buffer-overrun-when-composing-a-n.patch --]
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3.6.11.6 stable review patch.
If anyone has any objections, please let me know.

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

From: Jeff Layton <jlayton@redhat.com>

[ Upstream commit 166faf21bd14bc5c5295a44874bf7f3930c30b20 ]

Consider the case where we have a very short ip= string in the original
mount options, and when we chase a referral we end up with a very long
IPv6 address. Be sure to allow for that possibility when estimating the
size of the string to allocate.

Cc: <stable@vger.kernel.org>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
fs/cifs/cifs_dfs_ref.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/cifs/cifs_dfs_ref.c b/fs/cifs/cifs_dfs_ref.c
index ce5cbd7..52527dd 100644
--- a/fs/cifs/cifs_dfs_ref.c
+++ b/fs/cifs/cifs_dfs_ref.c
@@ -18,6 +18,7 @@
#include <linux/slab.h>
#include <linux/vfs.h>
#include <linux/fs.h>
+#include <linux/inet.h>
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifsfs.h"
@@ -150,7 +151,8 @@ char *cifs_compose_mount_options(const char *sb_mountdata,
* assuming that we have 'unc=' and 'ip=' in
* the original sb_mountdata
*/
- md_len = strlen(sb_mountdata) + rc + strlen(ref->node_name) + 12;
+ md_len = strlen(sb_mountdata) + rc + strlen(ref->node_name) + 12 +
+ INET6_ADDRSTRLEN;
mountdata = kzalloc(md_len+1, GFP_KERNEL);
if (mountdata == NULL) {
rc = -ENOMEM;
--
1.7.10.4