cifs: change bleft in decode_unicode_ssetup back to signed type

The buffer length checks in this function depend on this value being a
signed data type, but 690c522fa converted it to an unsigned type.

Also, eliminate a problem with the null termination check in the same
function. cifs_strndup_from_ucs handles that situation correctly
already, and the existing check could potentially lead to a buffer
overrun since it increments bleft without checking to see whether it
falls off the end of the buffer.

Cc: stable@kernel.org
Reported-and-Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 1 insertions, 14 deletions

diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index f6728eb6f4b9..2e2c91103529 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -276,7 +276,7 @@ static void ascii_ssetup_strings(char **pbcc_area, struct cifsSesInfo *ses,
 }
 
 static void
-decode_unicode_ssetup(char **pbcc_area, __u16 bleft, struct cifsSesInfo *ses,
+decode_unicode_ssetup(char **pbcc_area, int bleft, struct cifsSesInfo *ses,
                       const struct nls_table *nls_cp)
 {
         int len;
@@ -284,19 +284,6 @@ decode_unicode_ssetup(char **pbcc_area, __u16 bleft, struct cifsSesInfo *ses,
 
         cFYI(1, "bleft %d", bleft);
 
-        /*
-         * Windows servers do not always double null terminate their final
-         * Unicode string. Check to see if there are an uneven number of bytes
-         * left. If so, then add an extra NULL pad byte to the end of the
-         * response.
-         *
-         * See section 2.7.2 in "Implementing CIFS" for details
-         */
-        if (bleft % 2) {
-                data[bleft] = 0;
-                ++bleft;
-        }
-
         kfree(ses->serverOS);
         ses->serverOS = cifs_strndup_from_ucs(data, bleft, true, nls_cp);
         cFYI(1, "serverOS=%s", ses->serverOS);