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, 234 insertions, 0 deletions

diff --git a/security/selinux/nlmsgtab.c b/security/selinux/nlmsgtab.c
new file mode 100644
index 000000000..655d2616c
--- /dev/null
+++ b/security/selinux/nlmsgtab.c
@@ -0,0 +1,234 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Netlink message type permission tables, for user generated messages.
+ *
+ * Author: James Morris <jmorris@redhat.com>
+ *
+ * Copyright (C) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
+ */
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <linux/if.h>
+#include <linux/inet_diag.h>
+#include <linux/xfrm.h>
+#include <linux/audit.h>
+#include <linux/sock_diag.h>
+
+#include "flask.h"
+#include "av_permissions.h"
+#include "security.h"
+
+struct nlmsg_perm {
+	u16 nlmsg_type;
+	u32 perm;
+};
+
+static const struct nlmsg_perm nlmsg_route_perms[] = {
+	{ RTM_NEWLINK, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELLINK, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETLINK, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_SETLINK, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_NEWADDR, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELADDR, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETADDR, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_NEWROUTE, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELROUTE, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETROUTE, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_NEWNEIGH, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELNEIGH, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETNEIGH, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_NEWRULE, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELRULE, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETRULE, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_NEWQDISC, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELQDISC, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETQDISC, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_NEWTCLASS, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELTCLASS, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETTCLASS, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_NEWTFILTER, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELTFILTER, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETTFILTER, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_NEWACTION, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELACTION, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETACTION, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_NEWPREFIX, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETMULTICAST, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_GETANYCAST, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_GETNEIGHTBL, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_SETNEIGHTBL, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_NEWADDRLABEL, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELADDRLABEL, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETADDRLABEL, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_GETDCB, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_SETDCB, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_NEWNETCONF, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELNETCONF, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETNETCONF, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_NEWMDB, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELMDB, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETMDB, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_NEWNSID, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELNSID, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_GETNSID, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_NEWSTATS, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_GETSTATS, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_SETSTATS, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_NEWCACHEREPORT, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_NEWCHAIN, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELCHAIN, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETCHAIN, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_NEWNEXTHOP, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELNEXTHOP, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETNEXTHOP, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_NEWLINKPROP, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELLINKPROP, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_NEWVLAN, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELVLAN, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETVLAN, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_NEWNEXTHOPBUCKET, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELNEXTHOPBUCKET, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETNEXTHOPBUCKET, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+	{ RTM_NEWTUNNEL, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELTUNNEL, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETTUNNEL, NETLINK_ROUTE_SOCKET__NLMSG_READ },
+};
+
+static const struct nlmsg_perm nlmsg_tcpdiag_perms[] = {
+	{ TCPDIAG_GETSOCK, NETLINK_TCPDIAG_SOCKET__NLMSG_READ },
+	{ SOCK_DIAG_BY_FAMILY, NETLINK_TCPDIAG_SOCKET__NLMSG_READ },
+	{ SOCK_DESTROY, NETLINK_TCPDIAG_SOCKET__NLMSG_WRITE },
+};
+
+static const struct nlmsg_perm nlmsg_xfrm_perms[] = {
+	{ XFRM_MSG_NEWSA, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_DELSA, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_GETSA, NETLINK_XFRM_SOCKET__NLMSG_READ },
+	{ XFRM_MSG_NEWPOLICY, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_DELPOLICY, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_GETPOLICY, NETLINK_XFRM_SOCKET__NLMSG_READ },
+	{ XFRM_MSG_ALLOCSPI, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_ACQUIRE, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_EXPIRE, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_UPDPOLICY, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_UPDSA, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_POLEXPIRE, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_FLUSHSA, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_FLUSHPOLICY, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_NEWAE, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_GETAE, NETLINK_XFRM_SOCKET__NLMSG_READ },
+	{ XFRM_MSG_REPORT, NETLINK_XFRM_SOCKET__NLMSG_READ },
+	{ XFRM_MSG_MIGRATE, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_NEWSADINFO, NETLINK_XFRM_SOCKET__NLMSG_READ },
+	{ XFRM_MSG_GETSADINFO, NETLINK_XFRM_SOCKET__NLMSG_READ },
+	{ XFRM_MSG_NEWSPDINFO, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_GETSPDINFO, NETLINK_XFRM_SOCKET__NLMSG_READ },
+	{ XFRM_MSG_MAPPING, NETLINK_XFRM_SOCKET__NLMSG_READ },
+	{ XFRM_MSG_SETDEFAULT, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_GETDEFAULT, NETLINK_XFRM_SOCKET__NLMSG_READ },
+	{ XFRM_MSG_MIGRATE_STATE, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+};
+
+static const struct nlmsg_perm nlmsg_audit_perms[] = {
+	{ AUDIT_GET, NETLINK_AUDIT_SOCKET__NLMSG_READ },
+	{ AUDIT_SET, NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
+	{ AUDIT_LIST, NETLINK_AUDIT_SOCKET__NLMSG_READPRIV },
+	{ AUDIT_ADD, NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
+	{ AUDIT_DEL, NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
+	{ AUDIT_LIST_RULES, NETLINK_AUDIT_SOCKET__NLMSG_READPRIV },
+	{ AUDIT_ADD_RULE, NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
+	{ AUDIT_DEL_RULE, NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
+	{ AUDIT_USER, NETLINK_AUDIT_SOCKET__NLMSG_RELAY },
+	{ AUDIT_SIGNAL_INFO, NETLINK_AUDIT_SOCKET__NLMSG_READ },
+	{ AUDIT_TRIM, NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
+	{ AUDIT_MAKE_EQUIV, NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
+	{ AUDIT_TTY_GET, NETLINK_AUDIT_SOCKET__NLMSG_READ },
+	{ AUDIT_TTY_SET, NETLINK_AUDIT_SOCKET__NLMSG_TTY_AUDIT },
+	{ AUDIT_GET_FEATURE, NETLINK_AUDIT_SOCKET__NLMSG_READ },
+	{ AUDIT_SET_FEATURE, NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
+};
+
+static int nlmsg_perm(u16 nlmsg_type, u32 *perm, const struct nlmsg_perm *tab,
+		      size_t tabsize)
+{
+	unsigned int i;
+	int err = -EINVAL;
+
+	for (i = 0; i < tabsize / sizeof(struct nlmsg_perm); i++)
+		if (nlmsg_type == tab[i].nlmsg_type) {
+			*perm = tab[i].perm;
+			err = 0;
+			break;
+		}
+
+	return err;
+}
+
+int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm)
+{
+	/* While it is possible to add a similar permission to other netlink
+	 * classes, note that the extended permission value is matched against
+	 * the nlmsg_type field. Notably, SECCLASS_NETLINK_GENERIC_SOCKET uses
+	 * dynamic values for this field, which means that it cannot be added
+	 * as-is.
+	 */
+
+	switch (sclass) {
+	case SECCLASS_NETLINK_ROUTE_SOCKET:
+		/* RTM_MAX always points to RTM_SETxxxx, ie RTM_NEWxxx + 3.
+		 * If the BUILD_BUG_ON() below fails you must update the
+		 * structures at the top of this file with the new mappings
+		 * before updating the BUILD_BUG_ON() macro!
+		 */
+		BUILD_BUG_ON(RTM_MAX != (RTM_NEWTUNNEL + 3));
+
+		if (selinux_policycap_netlink_xperm()) {
+			*perm = NETLINK_ROUTE_SOCKET__NLMSG;
+			return 0;
+		}
+		return nlmsg_perm(nlmsg_type, perm, nlmsg_route_perms,
+				  sizeof(nlmsg_route_perms));
+		break;
+	case SECCLASS_NETLINK_TCPDIAG_SOCKET:
+		if (selinux_policycap_netlink_xperm()) {
+			*perm = NETLINK_TCPDIAG_SOCKET__NLMSG;
+			return 0;
+		}
+		return nlmsg_perm(nlmsg_type, perm, nlmsg_tcpdiag_perms,
+				  sizeof(nlmsg_tcpdiag_perms));
+		break;
+	case SECCLASS_NETLINK_XFRM_SOCKET:
+		/* If the BUILD_BUG_ON() below fails you must update the
+		 * structures at the top of this file with the new mappings
+		 * before updating the BUILD_BUG_ON() macro!
+		 */
+		BUILD_BUG_ON(XFRM_MSG_MAX != XFRM_MSG_MIGRATE_STATE);
+
+		if (selinux_policycap_netlink_xperm()) {
+			*perm = NETLINK_XFRM_SOCKET__NLMSG;
+			return 0;
+		}
+		return nlmsg_perm(nlmsg_type, perm, nlmsg_xfrm_perms,
+				  sizeof(nlmsg_xfrm_perms));
+		break;
+	case SECCLASS_NETLINK_AUDIT_SOCKET:
+		if (selinux_policycap_netlink_xperm()) {
+			*perm = NETLINK_AUDIT_SOCKET__NLMSG;
+			return 0;
+		} else if ((nlmsg_type >= AUDIT_FIRST_USER_MSG &&
+			    nlmsg_type <= AUDIT_LAST_USER_MSG) ||
+			   (nlmsg_type >= AUDIT_FIRST_USER_MSG2 &&
+			    nlmsg_type <= AUDIT_LAST_USER_MSG2)) {
+			*perm = NETLINK_AUDIT_SOCKET__NLMSG_RELAY;
+			return 0;
+		}
+		return nlmsg_perm(nlmsg_type, perm, nlmsg_audit_perms,
+				  sizeof(nlmsg_audit_perms));
+		break;
+	}
+
+	/* No messaging from userspace, or class unknown/unhandled */
+	return -ENOENT;
+}