From: Marios Makassikis <mmakassikis@xxxxxxxxxx>
commit 5fde3c21cf33830eda7bfd006dc7f4bf07ec9fe6 upstream.
If ksmbd.mountd is configured to assign unknown users to the guest account
("map to guest = bad user" in the config), ksmbd signs the response.
This is wrong according to MS-SMB2 3.3.5.5.3:
12. If the SMB2_SESSION_FLAG_IS_GUEST bit is not set in the SessionFlags
field, and Session.IsAnonymous is FALSE, the server MUST sign the
final session setup response before sending it to the client, as
follows:
[...]
This fixes libsmb2 based applications failing to establish a session
("Wrong signature in received").
Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Marios Makassikis <mmakassikis@xxxxxxxxxx>
Acked-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ksmbd/smb2pdu.c | 2 ++
1 file changed, 2 insertions(+)
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -8657,6 +8657,7 @@ int smb3_decrypt_req(struct ksmbd_work *
bool smb3_11_final_sess_setup_resp(struct ksmbd_work *work)
{
struct ksmbd_conn *conn = work->conn;
+ struct ksmbd_session *sess = work->sess;
struct smb2_hdr *rsp = smb2_get_msg(work->response_buf);
if (conn->dialect < SMB30_PROT_ID)
@@ -8666,6 +8667,7 @@ bool smb3_11_final_sess_setup_resp(struc
rsp = ksmbd_resp_buf_next(work);
if (le16_to_cpu(rsp->Command) == SMB2_SESSION_SETUP_HE &&
+ sess->user && !user_guest(sess->user) &&
rsp->Status == STATUS_SUCCESS)
return true;
return false;
