Commit fcda7f45 authored Apr 27, 2011 by Jeff Layton Committed by Steve French Apr 29, 2011

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>

parent bfacf222

fs/cifs/sess.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -916,7 +916,9 @@ CIFS_SessSetup(unsigned int xid, struct cifsSesInfo *ses,
		}

		/* 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;