cifs: fix potential buffer overrun when composing a new options string

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>
This commit is contained in:
Jeff Layton 2013-05-24 07:40:04 -04:00 committed by Steve French
parent 62106e9627
commit 166faf21bd
1 changed files with 3 additions and 1 deletions

View File

@ -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;