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authorJeff Layton <jlayton@redhat.com>2011-04-27 13:25:51 -0400
committerSteve French <sfrench@us.ibm.com>2011-04-29 04:57:39 +0000
commitfcda7f4578bbf9717444ca6da8a421d21489d078 (patch)
tree5cf2fc99c067eb49f410ad095ca2cabec2fe86ac /fs/cifs/sess.c
parentbfacf2225a955bea9c41c707fc72ba16009674a0 (diff)
downloadlinux-fcda7f4578bbf9717444ca6da8a421d21489d078.tar.gz
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>
Diffstat (limited to 'fs/cifs/sess.c')
-rw-r--r--fs/cifs/sess.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 2e2c91103529..645114ad0a10 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -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;