The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 4587eee04e2ac7ac3ac9fa2bc164fb6e548f99cd Mon Sep 17 00:00:00 2001 From: Steve French <smfrench@xxxxxxxxx> Date: Wed, 25 Oct 2017 15:58:31 -0500 Subject: [PATCH] SMB3: Validate negotiate request must always be signed 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@xxxxxxxxxxxxxxx> Acked-by: Ronnie Sahlberg <lsahlber.redhat.com> Signed-off-by: Steve French <smfrench@xxxxxxxxx> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index ba58af747b43..5331631386a2 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -1979,6 +1979,9 @@ 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);