cifs: Fix oops in session setup code for null user mounts

commit de47a4176c532ef5961b8a46a2d541a3517412d3 upstream.

For null user mounts, do not invoke string length function
during session setup.

Reported-and-Tested-by: Chris Clayton <chris2553@googlemail.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 4ec3ee9..2504809 100644 (file)
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -246,16 +246,15 @@ static void ascii_ssetup_strings(char **pbcc_area, struct cifs_ses *ses,
        /* copy user */
        /* BB what about null user mounts - check that we do this BB */
        /* copy user */
-       if (ses->user_name != NULL)
+       if (ses->user_name != NULL) {
                strncpy(bcc_ptr, ses->user_name, MAX_USERNAME_SIZE);
+               bcc_ptr += strnlen(ses->user_name, MAX_USERNAME_SIZE);
+       }
        /* else null user mount */
-
-       bcc_ptr += strnlen(ses->user_name, MAX_USERNAME_SIZE);
        *bcc_ptr = 0;
        bcc_ptr++; /* account for null termination */
 
        /* copy domain */
-
        if (ses->domainName != NULL) {
                strncpy(bcc_ptr, ses->domainName, 256);
                bcc_ptr += strnlen(ses->domainName, 256);