Patch "ksmbd: not allow guest user on multichannel" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    ksmbd: not allow guest user on multichannel

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ksmbd-not-allow-guest-user-on-multichannel.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit fad4b1d8a9cb53e6994d1d833c87daf421122327
Author: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Date:   Wed May 3 08:45:08 2023 +0900

    ksmbd: not allow guest user on multichannel
    
    [ Upstream commit 3353ab2df5f68dab7da8d5ebb427a2d265a1f2b2 ]
    
    This patch return STATUS_NOT_SUPPORTED if binding session is guest.
    
    Cc: stable@xxxxxxxxxxxxxxx
    Reported-by: zdi-disclosures@xxxxxxxxxxxxxx # ZDI-CAN-20480
    Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
    Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index 61d6d4b6b56ac..51d495688f45e 100644
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -1462,7 +1462,7 @@ static int ntlm_authenticate(struct ksmbd_work *work)
 		 * Reuse session if anonymous try to connect
 		 * on reauthetication.
 		 */
-		if (ksmbd_anonymous_user(user)) {
+		if (conn->binding == false && ksmbd_anonymous_user(user)) {
 			ksmbd_free_user(user);
 			return 0;
 		}
@@ -1476,7 +1476,7 @@ static int ntlm_authenticate(struct ksmbd_work *work)
 		sess->user = user;
 	}
 
-	if (user_guest(sess->user)) {
+	if (conn->binding == false && user_guest(sess->user)) {
 		rsp->SessionFlags = SMB2_SESSION_FLAG_IS_GUEST_LE;
 	} else {
 		struct authenticate_message *authblob;
@@ -1720,6 +1720,11 @@ int smb2_sess_setup(struct ksmbd_work *work)
 			goto out_err;
 		}
 
+		if (user_guest(sess->user)) {
+			rc = -EOPNOTSUPP;
+			goto out_err;
+		}
+
 		conn->binding = true;
 	} else if ((conn->dialect < SMB30_PROT_ID ||
 		    server_conf.flags & KSMBD_GLOBAL_FLAG_SMB3_MULTICHANNEL) &&
@@ -1831,6 +1836,8 @@ int smb2_sess_setup(struct ksmbd_work *work)
 		rsp->hdr.Status = STATUS_NETWORK_SESSION_EXPIRED;
 	else if (rc == -ENOMEM)
 		rsp->hdr.Status = STATUS_INSUFFICIENT_RESOURCES;
+	else if (rc == -EOPNOTSUPP)
+		rsp->hdr.Status = STATUS_NOT_SUPPORTED;
 	else if (rc)
 		rsp->hdr.Status = STATUS_LOGON_FAILURE;