[PATCH AUTOSEL 5.0 049/262] cifs: Accept validate negotiate if server return NT_STATUS_NOT_SUPPORTED

Sasha Levin
2019-03-27T19:30:45Z

From: Namjae Jeon <linkinjeon@gmail.com>

[ Upstream commit 969ae8e8d4ee54c99134d3895f2adf96047f5bee ]

Old windows version or Netapp SMB server will return
NT_STATUS_NOT_SUPPORTED since they do not allow or implement
FSCTL_VALIDATE_NEGOTIATE_INFO. The client should accept the response
provided it's properly signed.

See
https://blogs.msdn.microsoft.com/openspecification/2012/06/28/smb3-secure-dialect-negotiation/

and

MS-SMB2 validate negotiate response processing:
https://msdn.microsoft.com/en-us/library/hh880630.aspx

Samba client had already handled it.
https://bugzilla.samba.org/attachment.cgi?id=13285&action=edit

Signed-off-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/cifs/smb2pdu.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 77b3aaa39b35..4efeb2a02ea4 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -986,8 +986,14 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
FSCTL_VALIDATE_NEGOTIATE_INFO, true /* is_fsctl */,
(char *)pneg_inbuf, inbuflen, (char **)&pneg_rsp, &rsplen);
-
- if (rc != 0) {
+ if (rc == -EOPNOTSUPP) {
+ /*
+ * Old Windows versions or Netapp SMB server can return
+ * not supported error. Client should accept it.
+ */
+ cifs_dbg(VFS, "Server does not support validate negotiate\n");
+ return 0;
+ } else if (rc != 0) {
cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", rc);
rc = -EIO;
goto out_free_inbuf;
--
2.19.1