cifs: check for bytes_remaining going to zero in CIFS_SessSetup

It's possible that when we go to decode the string area in the
SESSION_SETUP response, that bytes_remaining will be 0. Decrementing it at
that point will mean that it can go "negative" and wrap. Check for a
bytes_remaining value of 0, and don't try to decode the string area if
that's the case.

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>
This commit is contained in:
Jeff Layton 2011-04-27 13:25:51 -04:00 committed by Steve French
parent bfacf2225a
commit fcda7f4578

View File

@ -916,7 +916,9 @@ ssetup_ntlmssp_authenticate:
}
/* BB check if Unicode and decode strings */
if (smb_buf->Flags2 & SMBFLG2_UNICODE) {
if (bytes_remaining == 0) {
/* no string area to decode, do nothing */
} else if (smb_buf->Flags2 & SMBFLG2_UNICODE) {
/* unicode string area must be word-aligned */
if (((unsigned long) bcc_ptr - (unsigned long) smb_buf) % 2) {
++bcc_ptr;