[CIFS] possible memory corruption on mount

CIFS cleanup_volume_info_contents() looks like having a memory
corruption problem.
When UNCip is set to "&vol->UNC[2]" in cifs_parse_mount_options(), it
should not be kfree()-ed in cleanup_volume_info_contents().

Introduced in commit b946845a9dc523c759cae2b6a0f6827486c3221a

Signed-off-by: J.R. Okajima <hooanon05@yahoo.co.jp>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
CC: Stable <stable@kernel.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 80c2e3a..633c246 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2878,7 +2878,8 @@ cleanup_volume_info_contents(struct smb_vol *volume_info)
        kfree(volume_info->username);
        kzfree(volume_info->password);
        kfree(volume_info->UNC);
-       kfree(volume_info->UNCip);
+       if (volume_info->UNCip != volume_info->UNC + 2)
+               kfree(volume_info->UNCip);
        kfree(volume_info->domainname);
        kfree(volume_info->iocharset);
        kfree(volume_info->prepath);