[SRU][Xenial][Zesty][Artful][PATCH 1/1] SMB3: Validate negotiate request must always be signed

[Joseph Salisbury]

From: Steve French <smfrench at gmail.com>

BugLink: http://bugs.launchpad.net/bugs/1729337

According to MS-SMB2 3.2.55 validate_negotiate request must
always be signed. Some Windows can fail the request if you send it unsigned

See kernel bugzilla bug 197311

CC: Stable <stable at vger.kernel.org>
Acked-by: Ronnie Sahlberg <lsahlber.redhat.com>
Signed-off-by: Steve French <smfrench at gmail.com>
(cherry picked from commit 4587eee04e2ac7ac3ac9fa2bc164fb6e548f99cd)
Signed-off-by: Joseph Salisbury <joseph.salisbury at canonical.com>
---
 fs/cifs/smb2pdu.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 7aa6720..58ce078 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -1888,6 +1888,9 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 	} else
 		iov[0].iov_len = get_rfc1002_length(req) + 4;
 
+	/* validate negotiate request must be signed - see MS-SMB2 3.2.5.5 */
+	if (opcode == FSCTL_VALIDATE_NEGOTIATE_INFO)
+		req->hdr.sync_hdr.Flags |= SMB2_FLAGS_SIGNED;
 
 	rc = SendReceive2(xid, ses, iov, n_iov, &resp_buftype, flags, &rsp_iov);
 	cifs_small_buf_release(req);
-- 
2.7.4