[CIFS] allow cifs_calc_signature2 to deal with a zero length iovec

Currently, cifs_calc_signature2 errors out if it gets a zero-length
iovec. Fix it to silently continue in that case.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index 632070b4275d..788f0ad6feda 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -99,11 +99,12 @@ static int cifs_calc_signature2(const struct kvec *iov, int n_vec,
         MD5Init(&context);
         MD5Update(&context, (char *)&key->data, key->len);
         for (i = 0; i < n_vec; i++) {
+                if (iov[i].iov_len == 0)
+                        continue;
                 if (iov[i].iov_base == NULL) {
                         cERROR(1, ("null iovec entry"));
                         return -EIO;
-                } else if (iov[i].iov_len == 0)
-                        break; /* bail out if we are sent nothing to sign */
+                }
                 /* The first entry includes a length field (which does not get
                    signed that occupies the first 4 bytes before the header */
                 if (i == 0) {