[PATCH] SELinux: Fine-grained Netlink support - SELinux changes

This patch contains SELinux changes which add support for extended Netlink
socket classes and the associated permissions nlmsg_read and nlmsg_write.

Cc: David S. Miller <davem@redhat.com>
Signed-off-by: James Morris <jmorris@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

security/selinux/Makefile

@@ -4,7 +4,7 @@
 
 obj-$(CONFIG_SECURITY_SELINUX) := selinux.o ss/
 
-selinux-y := avc.o hooks.o selinuxfs.o netlink.o
+selinux-y := avc.o hooks.o selinuxfs.o netlink.o nlmsgtab.o
 
 selinux-$(CONFIG_SECURITY_NETWORK) += netif.o
 

security/selinux/hooks.c

@@ -71,6 +71,9 @@
 #define XATTR_SELINUX_SUFFIX "selinux"
 #define XATTR_NAME_SELINUX XATTR_SECURITY_PREFIX XATTR_SELINUX_SUFFIX
 
+extern int policydb_loaded_version;
+extern int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm);
+
 #ifdef CONFIG_SECURITY_SELINUX_DEVELOP
 int selinux_enforcing = 0;
 
@@ -627,7 +630,7 @@ static inline u16 inode_mode_to_security_class(umode_t mode)
 	return SECCLASS_FILE;
 }
 
-static inline u16 socket_type_to_security_class(int family, int type)
+static inline u16 socket_type_to_security_class(int family, int type, int protocol)
 {
 	switch (family) {
 	case PF_UNIX:
@@ -648,7 +651,28 @@ static inline u16 socket_type_to_security_class(int family, int type)
 			return SECCLASS_RAWIP_SOCKET;
 		}
 	case PF_NETLINK:
+		switch (protocol) {
+		case NETLINK_ROUTE:
+			return SECCLASS_NETLINK_ROUTE_SOCKET;
+		case NETLINK_FIREWALL:
+			return SECCLASS_NETLINK_FIREWALL_SOCKET;
+		case NETLINK_TCPDIAG:
+			return SECCLASS_NETLINK_TCPDIAG_SOCKET;
+		case NETLINK_NFLOG:
+			return SECCLASS_NETLINK_NFLOG_SOCKET;
+		case NETLINK_XFRM:
+			return SECCLASS_NETLINK_XFRM_SOCKET;
+		case NETLINK_SELINUX:
+			return SECCLASS_NETLINK_SELINUX_SOCKET;
+		case NETLINK_AUDIT:
+			return SECCLASS_NETLINK_AUDIT_SOCKET;
+		case NETLINK_IP6_FW:
+			return SECCLASS_NETLINK_IP6FW_SOCKET;
+		case NETLINK_DNRTMSG:
+			return SECCLASS_NETLINK_DNRT_SOCKET;
+		default:
 			return SECCLASS_NETLINK_SOCKET;
+		}
 	case PF_PACKET:
 		return SECCLASS_PACKET_SOCKET;
 	case PF_KEY:
@@ -853,7 +877,8 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
 		struct socket *sock = SOCKET_I(inode);
 		if (sock->sk) {
 			isec->sclass = socket_type_to_security_class(sock->sk->sk_family,
-			                                             sock->sk->sk_type);
+			                                             sock->sk->sk_type,
+			                                             sock->sk->sk_protocol);
 		} else {
 			isec->sclass = SECCLASS_SOCKET;
 		}
@@ -1567,22 +1592,6 @@ static int selinux_vm_enough_memory(long pages)
 	return -ENOMEM;
 }
 
-static int selinux_netlink_send(struct sock *sk, struct sk_buff *skb)
-{
-	if (capable(CAP_NET_ADMIN))
-		cap_raise (NETLINK_CB (skb).eff_cap, CAP_NET_ADMIN);
-	else
-		NETLINK_CB(skb).eff_cap = 0;
-	return 0;
-}
-
-static int selinux_netlink_recv(struct sk_buff *skb)
-{
-	if (!cap_raised(NETLINK_CB(skb).eff_cap, CAP_NET_ADMIN))
-		return -EPERM;
-	return 0;
-}
-
 /* binprm security operations */
 
 static int selinux_bprm_alloc_security(struct linux_binprm *bprm)
@@ -2918,8 +2927,8 @@ static int selinux_socket_create(int family, int type,
 
 	tsec = current->security;
 	err = avc_has_perm(tsec->sid, tsec->sid,
-			   socket_type_to_security_class(family, type),
-			   SOCKET__CREATE, NULL, NULL);
+			   socket_type_to_security_class(family, type,
+			   protocol), SOCKET__CREATE, NULL, NULL);
 
 out:
 	return err;
@@ -2938,7 +2947,7 @@ static void selinux_socket_post_create(struct socket *sock, int family,
 	isec = SOCK_INODE(sock)->i_security;
 
 	tsec = current->security;
-	isec->sclass = socket_type_to_security_class(family, type);
+	isec->sclass = socket_type_to_security_class(family, type, protocol);
 	isec->sid = kern ? SECINITSID_KERNEL : tsec->sid;
 
 	return;
@@ -3327,6 +3336,55 @@ static void selinux_sk_free_security(struct sock *sk)
 	sk_free_security(sk);
 }
 
+static int selinux_nlmsg_perm(struct sock *sk, struct sk_buff *skb)
+{
+	int err = 0;
+	u32 perm;
+	struct nlmsghdr *nlh;
+	struct socket *sock = sk->sk_socket;
+	struct inode_security_struct *isec = SOCK_INODE(sock)->i_security;
+
+	if (skb->len < NLMSG_SPACE(0)) {
+		err = -EINVAL;
+		goto out;
+	}
+	nlh = (struct nlmsghdr *)skb->data;
+
+	err = selinux_nlmsg_lookup(isec->sclass, nlh->nlmsg_type, &perm);
+	if (err) {
+		/* Ignore */
+		if (err == -ENOENT)
+			err = 0;
+		goto out;
+	}
+
+	err = socket_has_perm(current, sock, perm);
+out:
+	return err;
+}
+
+static int selinux_netlink_send(struct sock *sk, struct sk_buff *skb)
+{
+	int err = 0;
+
+	if (capable(CAP_NET_ADMIN))
+		cap_raise (NETLINK_CB (skb).eff_cap, CAP_NET_ADMIN);
+	else
+		NETLINK_CB(skb).eff_cap = 0;
+
+	if (policydb_loaded_version >= POLICYDB_VERSION_NLCLASS)
+		err = selinux_nlmsg_perm(sk, skb);
+
+	return err;
+}
+
+static int selinux_netlink_recv(struct sk_buff *skb)
+{
+	if (!cap_raised(NETLINK_CB(skb).eff_cap, CAP_NET_ADMIN))
+		return -EPERM;
+	return 0;
+}
+
 #ifdef CONFIG_NETFILTER
 
 static unsigned int selinux_ip_postroute_last(unsigned int hooknum,

security/selinux/include/av_inherit.h

@@ -29,6 +29,15 @@ static struct av_inherit av_inherit[] = {
    { SECCLASS_SEM, common_ipc_perm_to_string, 0x00000200UL },
    { SECCLASS_MSGQ, common_ipc_perm_to_string, 0x00000200UL },
    { SECCLASS_SHM, common_ipc_perm_to_string, 0x00000200UL },
+   { SECCLASS_NETLINK_ROUTE_SOCKET, common_socket_perm_to_string, 0x00400000UL },
+   { SECCLASS_NETLINK_FIREWALL_SOCKET, common_socket_perm_to_string, 0x00400000UL },
+   { SECCLASS_NETLINK_TCPDIAG_SOCKET, common_socket_perm_to_string, 0x00400000UL },
+   { SECCLASS_NETLINK_NFLOG_SOCKET, common_socket_perm_to_string, 0x00400000UL },
+   { SECCLASS_NETLINK_XFRM_SOCKET, common_socket_perm_to_string, 0x00400000UL },
+   { SECCLASS_NETLINK_SELINUX_SOCKET, common_socket_perm_to_string, 0x00400000UL },
+   { SECCLASS_NETLINK_AUDIT_SOCKET, common_socket_perm_to_string, 0x00400000UL },
+   { SECCLASS_NETLINK_IP6FW_SOCKET, common_socket_perm_to_string, 0x00400000UL },
+   { SECCLASS_NETLINK_DNRT_SOCKET, common_socket_perm_to_string, 0x00400000UL },
 };
 
 

security/selinux/include/av_perm_to_string.h

@@ -207,6 +207,18 @@ static struct av_perm_to_string av_perm_to_string[] = {
    { SECCLASS_PAX, PAX__RANDMMAP, "randmmap" },
    { SECCLASS_PAX, PAX__RANDEXEC, "randexec" },
    { SECCLASS_PAX, PAX__SEGMEXEC, "segmexec" },
+   { SECCLASS_NETLINK_ROUTE_SOCKET, NETLINK_ROUTE_SOCKET__NLMSG_READ, "nlmsg_read" },
+   { SECCLASS_NETLINK_ROUTE_SOCKET, NETLINK_ROUTE_SOCKET__NLMSG_WRITE, "nlmsg_write" },
+   { SECCLASS_NETLINK_FIREWALL_SOCKET, NETLINK_FIREWALL_SOCKET__NLMSG_READ, "nlmsg_read" },
+   { SECCLASS_NETLINK_FIREWALL_SOCKET, NETLINK_FIREWALL_SOCKET__NLMSG_WRITE, "nlmsg_write" },
+   { SECCLASS_NETLINK_TCPDIAG_SOCKET, NETLINK_TCPDIAG_SOCKET__NLMSG_READ, "nlmsg_read" },
+   { SECCLASS_NETLINK_TCPDIAG_SOCKET, NETLINK_TCPDIAG_SOCKET__NLMSG_WRITE, "nlmsg_write" },
+   { SECCLASS_NETLINK_XFRM_SOCKET, NETLINK_XFRM_SOCKET__NLMSG_READ, "nlmsg_read" },
+   { SECCLASS_NETLINK_XFRM_SOCKET, NETLINK_XFRM_SOCKET__NLMSG_WRITE, "nlmsg_write" },
+   { SECCLASS_NETLINK_AUDIT_SOCKET, NETLINK_AUDIT_SOCKET__NLMSG_READ, "nlmsg_read" },
+   { SECCLASS_NETLINK_AUDIT_SOCKET, NETLINK_AUDIT_SOCKET__NLMSG_WRITE, "nlmsg_write" },
+   { SECCLASS_NETLINK_IP6FW_SOCKET, NETLINK_IP6FW_SOCKET__NLMSG_READ, "nlmsg_read" },
+   { SECCLASS_NETLINK_IP6FW_SOCKET, NETLINK_IP6FW_SOCKET__NLMSG_WRITE, "nlmsg_write" },
 };
 
 

security/selinux/include/class_to_string.h

@@ -47,5 +47,14 @@ static char *class_to_string[] =
     "xserver",
     "xextension",
     "pax",
+    "netlink_route_socket",
+    "netlink_firewall_socket",
+    "netlink_tcpdiag_socket",
+    "netlink_nflog_socket",
+    "netlink_xfrm_socket",
+    "netlink_selinux_socket",
+    "netlink_audit_socket",
+    "netlink_ip6fw_socket",
+    "netlink_dnrt_socket",
 };
 

security/selinux/include/flask.h

@@ -47,6 +47,15 @@
 #define SECCLASS_XSERVER                                 40
 #define SECCLASS_XEXTENSION                              41
 #define SECCLASS_PAX                                     42
+#define SECCLASS_NETLINK_ROUTE_SOCKET                    43
+#define SECCLASS_NETLINK_FIREWALL_SOCKET                 44
+#define SECCLASS_NETLINK_TCPDIAG_SOCKET                  45
+#define SECCLASS_NETLINK_NFLOG_SOCKET                    46
+#define SECCLASS_NETLINK_XFRM_SOCKET                     47
+#define SECCLASS_NETLINK_SELINUX_SOCKET                  48
+#define SECCLASS_NETLINK_AUDIT_SOCKET                    49
+#define SECCLASS_NETLINK_IP6FW_SOCKET                    50
+#define SECCLASS_NETLINK_DNRT_SOCKET                     51
 
 /*
  * Security identifier indices for initial entities

security/selinux/include/security.h

@@ -20,10 +20,11 @@
 #define POLICYDB_VERSION_BASE		15
 #define POLICYDB_VERSION_BOOL		16
 #define POLICYDB_VERSION_IPV6		17
+#define POLICYDB_VERSION_NLCLASS	18
 
 /* Range of policy versions we understand*/
 #define POLICYDB_VERSION_MIN   POLICYDB_VERSION_BASE
-#define POLICYDB_VERSION_MAX   POLICYDB_VERSION_IPV6
+#define POLICYDB_VERSION_MAX   POLICYDB_VERSION_NLCLASS
 
 #ifdef CONFIG_SECURITY_SELINUX_BOOTPARAM
 extern int selinux_enabled;

security/selinux/nlmsgtab.c

+/*
+ * 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>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2,
+ * as published by the Free Software Foundation.
+ */
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <linux/if.h>
+#include <linux/netfilter_ipv4/ip_queue.h>
+#include <linux/tcp_diag.h>
+#include <linux/xfrm.h>
+#include <linux/audit.h>
+
+#include "flask.h"
+#include "av_permissions.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_NEWPREFIX,	NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETPREFIX,	NETLINK_ROUTE_SOCKET__NLMSG_READ  },
+	{ RTM_GETMULTICAST,	NETLINK_ROUTE_SOCKET__NLMSG_READ  },
+	{ RTM_GETANYCAST,	NETLINK_ROUTE_SOCKET__NLMSG_READ  },
+};
+
+static struct nlmsg_perm nlmsg_firewall_perms[] =
+{
+	{ IPQM_MODE,		NETLINK_FIREWALL_SOCKET__NLMSG_WRITE },
+	{ IPQM_VERDICT,		NETLINK_FIREWALL_SOCKET__NLMSG_WRITE },
+};
+
+static struct nlmsg_perm nlmsg_tcpdiag_perms[] =
+{
+	{ TCPDIAG_GETSOCK,	NETLINK_TCPDIAG_SOCKET__NLMSG_READ },
+};
+
+static 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_UPDPOLICY,	NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_UPDSA,	NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+};
+
+static 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_READ  },
+	{ AUDIT_ADD,		NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
+	{ AUDIT_DEL,		NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
+	{ AUDIT_USER,		NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
+	{ AUDIT_LOGIN,		NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
+};
+
+
+static int nlmsg_perm(u16 nlmsg_type, u32 *perm, 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:
+		err = nlmsg_perm(nlmsg_type, perm, nlmsg_route_perms,
+				 sizeof(nlmsg_route_perms));
+		break;
+
+	case SECCLASS_NETLINK_FIREWALL_SOCKET:
+	case NETLINK_IP6_FW:
+		err = nlmsg_perm(nlmsg_type, perm, nlmsg_firewall_perms,
+				 sizeof(nlmsg_firewall_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:
+		err = nlmsg_perm(nlmsg_type, perm, nlmsg_xfrm_perms,
+				 sizeof(nlmsg_xfrm_perms));
+		break;
+
+	case SECCLASS_NETLINK_AUDIT_SOCKET:
+		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;
+}

security/selinux/ss/policydb.c

@@ -38,6 +38,8 @@ static char *symtab_name[SYM_NUM] = {
 };
 #endif
 
+int policydb_loaded_version;
+
 static unsigned int symtab_sizes[SYM_NUM] = {
 	2,
 	32,
@@ -71,6 +73,11 @@ static struct policydb_compat_info policydb_compat[] = {
 		.sym_num        = SYM_NUM,
 		.ocon_num       = OCON_NUM,
 	},
+	{
+		.version        = POLICYDB_VERSION_NLCLASS,
+		.sym_num        = SYM_NUM,
+		.ocon_num       = OCON_NUM,
+	},
 };
 
 static struct policydb_compat_info *policydb_lookup_compat(int version)
@@ -1125,7 +1132,7 @@ int policydb_read(struct policydb *p, void *fp)
 	struct role_trans *tr, *ltr;
 	struct ocontext *l, *c, *newc;
 	struct genfs *genfs_p, *genfs, *newgenfs;
-	int i, j, rc, r_policyvers;
+	int i, j, rc, r_policyvers = 0;
 	u32 *buf, len, len2, config, nprim, nel, nel2;
 	char *policydb_str;
 	struct policydb_compat_info *info;
@@ -1546,6 +1553,7 @@ int policydb_read(struct policydb *p, void *fp)
 	if (rc)
 		goto bad;
 out:
+	policydb_loaded_version = r_policyvers;
 	return rc;
 bad_newc:
 	ocontext_destroy(newc,OCON_FSUSE);

security/selinux/ss/services.c

@@ -40,6 +40,7 @@
 #include "mls.h"
 
 extern void selnl_notify_policyload(u32 seqno);
+extern int policydb_loaded_version;
 
 static rwlock_t policy_rwlock = RW_LOCK_UNLOCKED;
 #define POLICY_RDLOCK read_lock(&policy_rwlock)
@@ -203,6 +204,17 @@ static int context_struct_compute_av(struct context *scontext,
 	struct avtab_datum *avdatum;
 	struct class_datum *tclass_datum;
 
+	/*
+	 * Remap extended Netlink classes for old policy versions.
+	 * Do this here rather than socket_type_to_security_class()
+	 * in case a newer policy version is loaded, allowing sockets
+	 * to remain in the correct class.
+	 */
+	if (policydb_loaded_version < POLICYDB_VERSION_NLCLASS)
+		if (tclass >= SECCLASS_NETLINK_ROUTE_SOCKET &&
+		    tclass <= SECCLASS_NETLINK_DNRT_SOCKET)
+			tclass = SECCLASS_NETLINK_SOCKET;
+
 	if (!tclass || tclass > policydb.p_classes.nprim) {
 		printk(KERN_ERR "security_compute_av:  unrecognized class %d\n",
 		       tclass);