openrisc: fix arbitrary kernel memory access via or1k_atomic syscallgrafted

sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user
pointers, v1 and v2, and swaps the words they point to in hand-written
assembly.

    l.lwz   r29,0(r4)
    l.lwz   r27,0(r5)
    l.sw    0(r4),r27
    l.sw    0(r5),r29

The pointers are not checked with access_ok(). The four memory
accesses also have no exception table entries.

A caller passes a kernel address as either pointer, and the syscall
reads from and writes to it directly.

This gives an unprivileged process a kernel read/write primitive. It
overwrites kernel data such as the sys_call_table, gaining code
execution in kernel context.

Check both pointers before entering the critical section. Add fixups
for the four memory accesses so faults on valid but unmapped user
addresses return -EFAULT.

[shorne@gmail.com: fix comment style]
Fixes: 9d02a4283e9c ("OpenRISC: Boot code")
Cc: stable@vger.kernel.org
Signed-off-by: Ali Ahmet Memis <ali@iusegentoo.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

1 files changed, 75 insertions, 0 deletions

diff --git a/fs/smb/server/server.h b/fs/smb/server/server.h
new file mode 100644
index 000000000..b8a7317be
--- /dev/null
+++ b/fs/smb/server/server.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *   Copyright (C) 2018 Samsung Electronics Co., Ltd.
+ */
+
+#ifndef __SERVER_H__
+#define __SERVER_H__
+
+#include "smbacl.h"
+
+/*
+ * Server state type
+ */
+enum {
+	SERVER_STATE_STARTING_UP,
+	SERVER_STATE_RUNNING,
+	SERVER_STATE_RESETTING,
+	SERVER_STATE_SHUTTING_DOWN,
+};
+
+/*
+ * Server global config string index
+ */
+enum {
+	SERVER_CONF_NETBIOS_NAME,
+	SERVER_CONF_SERVER_STRING,
+	SERVER_CONF_WORK_GROUP,
+};
+
+struct ksmbd_server_config {
+	unsigned int		flags;
+	unsigned int		state;
+	short			signing;
+	short			enforced_signing;
+	short			min_protocol;
+	short			max_protocol;
+	unsigned short		tcp_port;
+	unsigned short		ipc_timeout;
+	unsigned long		ipc_last_active;
+	unsigned long		deadtime;
+	unsigned int		share_fake_fscaps;
+	struct smb_sid		domain_sid;
+	unsigned int		auth_mechs;
+	unsigned int		max_connections;
+	unsigned int		max_inflight_req;
+	unsigned int		max_ip_connections;
+
+	char			*conf[SERVER_CONF_WORK_GROUP + 1];
+	struct task_struct	*dh_task;
+	bool			bind_interfaces_only;
+};
+
+extern struct ksmbd_server_config server_conf;
+
+int ksmbd_set_netbios_name(char *v);
+int ksmbd_set_server_string(char *v);
+int ksmbd_set_work_group(char *v);
+
+char *ksmbd_netbios_name(void);
+char *ksmbd_server_string(void);
+char *ksmbd_work_group(void);
+
+static inline int ksmbd_server_running(void)
+{
+	return READ_ONCE(server_conf.state) == SERVER_STATE_RUNNING;
+}
+
+static inline int ksmbd_server_configurable(void)
+{
+	return READ_ONCE(server_conf.state) < SERVER_STATE_RESETTING;
+}
+
+int server_queue_ctrl_init_work(void);
+int server_queue_ctrl_reset_work(void);
+#endif /* __SERVER_H__ */