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, 101 insertions, 0 deletions

diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
new file mode 100644
index 000000000..0da652844
--- /dev/null
+++ b/net/netlabel/netlabel_user.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * NetLabel NETLINK Interface
+ *
+ * This file defines the NETLINK interface for the NetLabel system.  The
+ * NetLabel system manages static and dynamic label mappings for network
+ * protocols such as CIPSO and RIPSO.
+ *
+ * Author: Paul Moore <paul@paul-moore.com>
+ */
+
+/*
+ * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
+ */
+
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/socket.h>
+#include <linux/audit.h>
+#include <linux/tty.h>
+#include <linux/security.h>
+#include <linux/gfp.h>
+#include <net/sock.h>
+#include <net/netlink.h>
+#include <net/genetlink.h>
+#include <net/netlabel.h>
+#include <asm/bug.h>
+
+#include "netlabel_mgmt.h"
+#include "netlabel_unlabeled.h"
+#include "netlabel_cipso_v4.h"
+#include "netlabel_calipso.h"
+#include "netlabel_user.h"
+
+/*
+ * NetLabel NETLINK Setup Functions
+ */
+
+/**
+ * netlbl_netlink_init - Initialize the NETLINK communication channel
+ *
+ * Description:
+ * Call out to the NetLabel components so they can register their families and
+ * commands with the Generic NETLINK mechanism.  Returns zero on success and
+ * non-zero on failure.
+ *
+ */
+int __init netlbl_netlink_init(void)
+{
+	int ret_val;
+
+	ret_val = netlbl_mgmt_genl_init();
+	if (ret_val != 0)
+		return ret_val;
+
+	ret_val = netlbl_cipsov4_genl_init();
+	if (ret_val != 0)
+		return ret_val;
+
+	ret_val = netlbl_calipso_genl_init();
+	if (ret_val != 0)
+		return ret_val;
+
+	return netlbl_unlabel_genl_init();
+}
+
+/*
+ * NetLabel Audit Functions
+ */
+
+/**
+ * netlbl_audit_start_common - Start an audit message
+ * @type: audit message type
+ * @audit_info: NetLabel audit information
+ *
+ * Description:
+ * Start an audit message using the type specified in @type and fill the audit
+ * message with some fields common to all NetLabel audit messages.  Returns
+ * a pointer to the audit buffer on success, NULL on failure.
+ *
+ */
+struct audit_buffer *netlbl_audit_start_common(int type,
+					       struct netlbl_audit *audit_info)
+{
+	struct audit_buffer *audit_buf;
+
+	if (audit_enabled == AUDIT_OFF)
+		return NULL;
+
+	audit_buf = audit_log_start(audit_context(), GFP_ATOMIC, type);
+	if (audit_buf == NULL)
+		return NULL;
+
+	audit_log_format(audit_buf, "netlabel: auid=%u ses=%u",
+			 from_kuid(&init_user_ns, audit_info->loginuid),
+			 audit_info->sessionid);
+	audit_log_subj_ctx(audit_buf, &audit_info->prop);
+
+	return audit_buf;
+}