smb: client: Fix match_session bug preventing session reuse

commit 605b249 upstream.

Fix a bug in match_session() that can causes the session to not be
reused in some cases.

Reproduction steps:

mount.cifs //server/share /mnt/a -o credentials=creds
mount.cifs //server/share /mnt/b -o credentials=creds,sec=ntlmssp
cat /proc/fs/cifs/DebugData | grep SessionId | wc -l

mount.cifs //server/share /mnt/b -o credentials=creds,sec=ntlmssp
mount.cifs //server/share /mnt/a -o credentials=creds
cat /proc/fs/cifs/DebugData | grep SessionId | wc -l

Cc: stable@vger.kernel.org
Reviewed-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Henrique Carvalho <henrique.carvalho@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: hac-v

fs/cifs/connect.c

@@ -1582,9 +1582,8 @@ cifs_get_tcp_session(struct smb3_fs_context *ctx)
 
 static int match_session(struct cifs_ses *ses, struct smb3_fs_context *ctx)
 {
-	if (ctx->sectype != Unspecified &&
-	    ctx->sectype != ses->sectype)
-		return 0;
+	struct TCP_Server_Info *server = ses->server;
+	enum securityEnum ctx_sec, ses_sec;
 
 	/*
 	 * If an existing session is limited to less channels than
@@ -1597,11 +1596,19 @@ static int match_session(struct cifs_ses *ses, struct smb3_fs_context *ctx)
 	}
 	spin_unlock(&ses->chan_lock);
 
-	switch (ses->sectype) {
+	ctx_sec = server->ops->select_sectype(server, ctx->sectype);
+	ses_sec = server->ops->select_sectype(server, ses->sectype);
+
+	if (ctx_sec != ses_sec)
+		return 0;
+
+	switch (ctx_sec) {
 	case Kerberos:
 		if (!uid_eq(ctx->cred_uid, ses->cred_uid))
 			return 0;
 		break;
+	case NTLMv2:
+	case RawNTLMSSP:
 	default:
 		/* NULL username means anonymous session */
 		if (ses->user_name == NULL) {