security/selinux/nlmsgtab.c

// 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 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_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  },
};

static const struct nlmsg_perm nlmsg_tcpdiag_perms[] =
{
	{ TCPDIAG_GETSOCK,	NETLINK_TCPDIAG_SOCKET__NLMSG_READ },
	{ DCCPDIAG_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  },
};

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)
{
	int i, 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)
{
	int err = 0;

	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_NEWVLAN + 3));
		err = nlmsg_perm(nlmsg_type, perm, nlmsg_route_perms,
				 sizeof(nlmsg_route_perms));
		break;

	case SECCLASS_NETLINK_TCPDIAG_SOCKET:
		err = 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_MAPPING);
		err = nlmsg_perm(nlmsg_type, perm, nlmsg_xfrm_perms,
				 sizeof(nlmsg_xfrm_perms));
		break;

	case SECCLASS_NETLINK_AUDIT_SOCKET:
		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;
		} else {
			err = nlmsg_perm(nlmsg_type, perm, nlmsg_audit_perms,
					 sizeof(nlmsg_audit_perms));
		}
		break;

	/* No messaging from userspace, or class unknown/unhandled */
	default:
		err = -ENOENT;
		break;
	}

	return err;
}

static void nlmsg_set_perm_for_type(u32 perm, u16 type)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(nlmsg_route_perms); i++) {
		if (nlmsg_route_perms[i].nlmsg_type == type) {
			nlmsg_route_perms[i].perm = perm;
			break;
		}
	}
}

/**
 * Use nlmsg_readpriv as the permission for RTM_GETLINK messages if the
 * netlink_route_getlink policy capability is set. Otherwise use nlmsg_read.
 * Similarly, use nlmsg_getneigh for RTM_GETNEIGH and RTM_GETNEIGHTBL if the
 * netlink_route_getneigh policy capability is set. Otherwise use nlmsg_read.
 */
void selinux_nlmsg_init(void)
{
	if (selinux_android_nlroute_getlink())
		nlmsg_set_perm_for_type(NETLINK_ROUTE_SOCKET__NLMSG_READPRIV,
					RTM_GETLINK);
	else
		nlmsg_set_perm_for_type(NETLINK_ROUTE_SOCKET__NLMSG_READ,
					RTM_GETLINK);

	if (selinux_android_nlroute_getneigh()) {
		nlmsg_set_perm_for_type(NETLINK_ROUTE_SOCKET__NLMSG_GETNEIGH,
					RTM_GETNEIGH);
		nlmsg_set_perm_for_type(NETLINK_ROUTE_SOCKET__NLMSG_GETNEIGH,
					RTM_GETNEIGHTBL);
	} else {
		nlmsg_set_perm_for_type(NETLINK_ROUTE_SOCKET__NLMSG_READ,
					RTM_GETNEIGH);
		nlmsg_set_perm_for_type(NETLINK_ROUTE_SOCKET__NLMSG_READ,
					RTM_GETNEIGHTBL);
	}
}