cifs: fix potential overflow in cifs_compose_mount_options

In worst case, "ip=" + sb_mountdata + ipv6 can be copied into mountdata.
Therefore, for safe, it is better to add more size when allocating memory.

Signed-off-by: Insu Yun <wuninsu@gmail.com>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/cifs/cifs_dfs_ref.c b/fs/cifs/cifs_dfs_ref.c
index 7dc886c9a78f..e956cba94338 100644
--- a/fs/cifs/cifs_dfs_ref.c
+++ b/fs/cifs/cifs_dfs_ref.c
@@ -175,7 +175,7 @@ char *cifs_compose_mount_options(const char *sb_mountdata,
          * string to the length of the original string to allow for worst case.
          */
         md_len = strlen(sb_mountdata) + INET6_ADDRSTRLEN;
-        mountdata = kzalloc(md_len + 1, GFP_KERNEL);
+        mountdata = kzalloc(md_len + sizeof("ip=") + 1, GFP_KERNEL);
         if (mountdata == NULL) {
                 rc = -ENOMEM;
                 goto compose_mount_options_err;