6 ksmbd SMB3 server fixes, most also for stable

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Merge tag 'v6.15-rc2-ksmbd-server-fixes' of git://git.samba.org/ksmbd

Pull smb server fixes from Steve French:

 - Fix integer overflow in server disconnect deadtime calculation

 - Three fixes for potential use after frees: one for oplocks, and one
   for leases and one for kerberos authentication

 - Fix to prevent attempted write to directory

 - Fix locking warning for durable scavenger thread

* tag 'v6.15-rc2-ksmbd-server-fixes' of git://git.samba.org/ksmbd:
  ksmbd: Prevent integer overflow in calculation of deadtime
  ksmbd: fix the warning from __kernel_write_iter
  ksmbd: fix use-after-free in smb_break_all_levII_oplock()
  ksmbd: fix use-after-free in __smb2_lease_break_noti()
  ksmbd: fix WARNING "do not call blocking ops when !TASK_RUNNING"
  ksmbd: Fix dangling pointer in krb_authenticate

fs/smb/server/connection.c

@@ -39,8 +39,10 @@ void ksmbd_conn_free(struct ksmbd_conn *conn)
 	xa_destroy(&conn->sessions);
 	kvfree(conn->request_buf);
 	kfree(conn->preauth_info);
-	if (atomic_dec_and_test(&conn->refcnt))
+	if (atomic_dec_and_test(&conn->refcnt)) {
+		ksmbd_free_transport(conn->transport);
 		kfree(conn);
+	}
 }
 
 /**

fs/smb/server/oplock.c

@@ -129,14 +129,6 @@ static void free_opinfo(struct oplock_info *opinfo)
 	kfree(opinfo);
 }
 
-static inline void opinfo_free_rcu(struct rcu_head *rcu_head)
-{
-	struct oplock_info *opinfo;
-
-	opinfo = container_of(rcu_head, struct oplock_info, rcu_head);
-	free_opinfo(opinfo);
-}
-
 struct oplock_info *opinfo_get(struct ksmbd_file *fp)
 {
 	struct oplock_info *opinfo;
@@ -157,8 +149,8 @@ static struct oplock_info *opinfo_get_list(struct ksmbd_inode *ci)
 	if (list_empty(&ci->m_op_list))
 		return NULL;
 
-	rcu_read_lock();
-	opinfo = list_first_or_null_rcu(&ci->m_op_list, struct oplock_info,
+	down_read(&ci->m_lock);
+	opinfo = list_first_entry(&ci->m_op_list, struct oplock_info,
 					op_entry);
 	if (opinfo) {
 		if (opinfo->conn == NULL ||
@@ -171,8 +163,7 @@ static struct oplock_info *opinfo_get_list(struct ksmbd_inode *ci)
 			}
 		}
 	}
-
-	rcu_read_unlock();
+	up_read(&ci->m_lock);
 
 	return opinfo;
 }
@@ -185,7 +176,7 @@ void opinfo_put(struct oplock_info *opinfo)
 	if (!atomic_dec_and_test(&opinfo->refcount))
 		return;
 
-	call_rcu(&opinfo->rcu_head, opinfo_free_rcu);
+	free_opinfo(opinfo);
 }
 
 static void opinfo_add(struct oplock_info *opinfo)
@@ -193,7 +184,7 @@ static void opinfo_add(struct oplock_info *opinfo)
 	struct ksmbd_inode *ci = opinfo->o_fp->f_ci;
 
 	down_write(&ci->m_lock);
-	list_add_rcu(&opinfo->op_entry, &ci->m_op_list);
+	list_add(&opinfo->op_entry, &ci->m_op_list);
 	up_write(&ci->m_lock);
 }
 
@@ -207,7 +198,7 @@ static void opinfo_del(struct oplock_info *opinfo)
 		write_unlock(&lease_list_lock);
 	}
 	down_write(&ci->m_lock);
-	list_del_rcu(&opinfo->op_entry);
+	list_del(&opinfo->op_entry);
 	up_write(&ci->m_lock);
 }
 
@@ -1347,8 +1338,8 @@ void smb_break_all_levII_oplock(struct ksmbd_work *work, struct ksmbd_file *fp,
 	ci = fp->f_ci;
 	op = opinfo_get(fp);
 
-	rcu_read_lock();
-	list_for_each_entry_rcu(brk_op, &ci->m_op_list, op_entry) {
+	down_read(&ci->m_lock);
+	list_for_each_entry(brk_op, &ci->m_op_list, op_entry) {
 		if (brk_op->conn == NULL)
 			continue;
 
@@ -1358,7 +1349,6 @@ void smb_break_all_levII_oplock(struct ksmbd_work *work, struct ksmbd_file *fp,
 		if (ksmbd_conn_releasing(brk_op->conn))
 			continue;
 
-		rcu_read_unlock();
 		if (brk_op->is_lease && (brk_op->o_lease->state &
 		    (~(SMB2_LEASE_READ_CACHING_LE |
 				SMB2_LEASE_HANDLE_CACHING_LE)))) {
@@ -1388,9 +1378,8 @@ void smb_break_all_levII_oplock(struct ksmbd_work *work, struct ksmbd_file *fp,
 		oplock_break(brk_op, SMB2_OPLOCK_LEVEL_NONE, NULL);
 next:
 		opinfo_put(brk_op);
-		rcu_read_lock();
 	}
-	rcu_read_unlock();
+	up_read(&ci->m_lock);
 
 	if (op)
 		opinfo_put(op);

fs/smb/server/oplock.h

@@ -71,7 +71,6 @@ struct oplock_info {
 	struct list_head        lease_entry;
 	wait_queue_head_t oplock_q; /* Other server threads */
 	wait_queue_head_t oplock_brk; /* oplock breaking wait */
-	struct rcu_head		rcu_head;
 };
 
 struct lease_break_info {

fs/smb/server/smb2pdu.c

@@ -1602,8 +1602,10 @@ static int krb5_authenticate(struct ksmbd_work *work,
 	if (prev_sess_id && prev_sess_id != sess->id)
 		destroy_previous_session(conn, sess->user, prev_sess_id);
 
-	if (sess->state == SMB2_SESSION_VALID)
+	if (sess->state == SMB2_SESSION_VALID) {
 		ksmbd_free_user(sess->user);
+		sess->user = NULL;
+	}
 
 	retval = ksmbd_krb5_authenticate(sess, in_blob, in_len,
 					 out_blob, &out_len);

fs/smb/server/transport_ipc.c

@@ -310,7 +310,11 @@ static int ipc_server_config_on_startup(struct ksmbd_startup_request *req)
 	server_conf.signing = req->signing;
 	server_conf.tcp_port = req->tcp_port;
 	server_conf.ipc_timeout = req->ipc_timeout * HZ;
-	server_conf.deadtime = req->deadtime * SMB_ECHO_INTERVAL;
+	if (check_mul_overflow(req->deadtime, SMB_ECHO_INTERVAL,
+					&server_conf.deadtime)) {
+		ret = -EINVAL;
+		goto out;
+	}
 	server_conf.share_fake_fscaps = req->share_fake_fscaps;
 	ksmbd_init_domain(req->sub_auth);
 
@@ -337,6 +341,7 @@ static int ipc_server_config_on_startup(struct ksmbd_startup_request *req)
 	server_conf.bind_interfaces_only = req->bind_interfaces_only;
 	ret |= ksmbd_tcp_set_interfaces(KSMBD_STARTUP_CONFIG_INTERFACES(req),
 					req->ifc_list_sz);
+out:
 	if (ret) {
 		pr_err("Server configuration error: %s %s %s\n",
 		       req->netbios_name, req->server_string,

fs/smb/server/transport_tcp.c

@@ -93,15 +93,19 @@ static struct tcp_transport *alloc_transport(struct socket *client_sk)
 	return t;
 }
 
+void ksmbd_free_transport(struct ksmbd_transport *kt)
+{
+	struct tcp_transport *t = TCP_TRANS(kt);
+
+	sock_release(t->sock);
+	kfree(t->iov);
+	kfree(t);
+}
+
 static void free_transport(struct tcp_transport *t)
 {
 	kernel_sock_shutdown(t->sock, SHUT_RDWR);
-	sock_release(t->sock);
-	t->sock = NULL;
-
 	ksmbd_conn_free(KSMBD_TRANS(t)->conn);
-	kfree(t->iov);
-	kfree(t);
 }
 
 /**

fs/smb/server/transport_tcp.h

@@ -8,6 +8,7 @@
 
 int ksmbd_tcp_set_interfaces(char *ifc_list, int ifc_list_sz);
 struct interface *ksmbd_find_netdev_name_iface_list(char *netdev_name);
+void ksmbd_free_transport(struct ksmbd_transport *kt);
 int ksmbd_tcp_init(void);
 void ksmbd_tcp_destroy(void);
 

fs/smb/server/vfs.c

@@ -479,7 +479,8 @@ int ksmbd_vfs_write(struct ksmbd_work *work, struct ksmbd_file *fp,
 	int err = 0;
 
 	if (work->conn->connection_type) {
-		if (!(fp->daccess & (FILE_WRITE_DATA_LE | FILE_APPEND_DATA_LE))) {
+		if (!(fp->daccess & (FILE_WRITE_DATA_LE | FILE_APPEND_DATA_LE)) ||
+		    S_ISDIR(file_inode(fp->filp)->i_mode)) {
 			pr_err("no right to write(%pD)\n", fp->filp);
 			err = -EACCES;
 			goto out;

fs/smb/server/vfs_cache.c

@@ -713,12 +713,8 @@ static bool tree_conn_fd_check(struct ksmbd_tree_connect *tcon,
 
 static bool ksmbd_durable_scavenger_alive(void)
 {
-	mutex_lock(&durable_scavenger_lock);
-	if (!durable_scavenger_running) {
-		mutex_unlock(&durable_scavenger_lock);
+	if (!durable_scavenger_running)
 		return false;
-	}
-	mutex_unlock(&durable_scavenger_lock);
 
 	if (kthread_should_stop())
 		return false;
@@ -799,9 +795,7 @@ static int ksmbd_durable_scavenger(void *dummy)
 			break;
 	}
 
-	mutex_lock(&durable_scavenger_lock);
 	durable_scavenger_running = false;
-	mutex_unlock(&durable_scavenger_lock);
 
 	module_put(THIS_MODULE);