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615 lines
16 KiB
615 lines
16 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* SELinux NetLabel Support |
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* |
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* This file provides the necessary glue to tie NetLabel into the SELinux |
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* subsystem. |
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* |
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* Author: Paul Moore <[email protected]> |
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*/ |
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|
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/* |
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* (c) Copyright Hewlett-Packard Development Company, L.P., 2007, 2008 |
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*/ |
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|
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#include <linux/spinlock.h> |
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#include <linux/rcupdate.h> |
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#include <linux/gfp.h> |
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#include <linux/ip.h> |
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#include <linux/ipv6.h> |
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#include <net/sock.h> |
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#include <net/netlabel.h> |
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#include <net/ip.h> |
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#include <net/ipv6.h> |
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|
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#include "objsec.h" |
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#include "security.h" |
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#include "netlabel.h" |
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|
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/** |
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* selinux_netlbl_sidlookup_cached - Cache a SID lookup |
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* @skb: the packet |
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* @family: the packet's address family |
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* @secattr: the NetLabel security attributes |
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* @sid: the SID |
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* |
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* Description: |
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* Query the SELinux security server to lookup the correct SID for the given |
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* security attributes. If the query is successful, cache the result to speed |
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* up future lookups. Returns zero on success, negative values on failure. |
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* |
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*/ |
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static int selinux_netlbl_sidlookup_cached(struct sk_buff *skb, |
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u16 family, |
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struct netlbl_lsm_secattr *secattr, |
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u32 *sid) |
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{ |
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int rc; |
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rc = security_netlbl_secattr_to_sid(&selinux_state, secattr, sid); |
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if (rc == 0 && |
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(secattr->flags & NETLBL_SECATTR_CACHEABLE) && |
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(secattr->flags & NETLBL_SECATTR_CACHE)) |
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netlbl_cache_add(skb, family, secattr); |
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return rc; |
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} |
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|
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/** |
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* selinux_netlbl_sock_genattr - Generate the NetLabel socket secattr |
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* @sk: the socket |
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* |
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* Description: |
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* Generate the NetLabel security attributes for a socket, making full use of |
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* the socket's attribute cache. Returns a pointer to the security attributes |
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* on success, NULL on failure. |
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* |
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*/ |
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static struct netlbl_lsm_secattr *selinux_netlbl_sock_genattr(struct sock *sk) |
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{ |
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int rc; |
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struct sk_security_struct *sksec = sk->sk_security; |
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struct netlbl_lsm_secattr *secattr; |
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if (sksec->nlbl_secattr != NULL) |
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return sksec->nlbl_secattr; |
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secattr = netlbl_secattr_alloc(GFP_ATOMIC); |
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if (secattr == NULL) |
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return NULL; |
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rc = security_netlbl_sid_to_secattr(&selinux_state, sksec->sid, |
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secattr); |
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if (rc != 0) { |
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netlbl_secattr_free(secattr); |
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return NULL; |
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} |
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sksec->nlbl_secattr = secattr; |
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return secattr; |
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} |
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/** |
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* selinux_netlbl_sock_getattr - Get the cached NetLabel secattr |
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* @sk: the socket |
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* @sid: the SID |
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* |
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* Query the socket's cached secattr and if the SID matches the cached value |
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* return the cache, otherwise return NULL. |
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* |
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*/ |
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static struct netlbl_lsm_secattr *selinux_netlbl_sock_getattr( |
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const struct sock *sk, |
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u32 sid) |
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{ |
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struct sk_security_struct *sksec = sk->sk_security; |
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struct netlbl_lsm_secattr *secattr = sksec->nlbl_secattr; |
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if (secattr == NULL) |
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return NULL; |
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if ((secattr->flags & NETLBL_SECATTR_SECID) && |
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(secattr->attr.secid == sid)) |
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return secattr; |
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return NULL; |
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} |
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/** |
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* selinux_netlbl_cache_invalidate - Invalidate the NetLabel cache |
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* |
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* Description: |
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* Invalidate the NetLabel security attribute mapping cache. |
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* |
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*/ |
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void selinux_netlbl_cache_invalidate(void) |
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{ |
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netlbl_cache_invalidate(); |
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} |
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/** |
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* selinux_netlbl_err - Handle a NetLabel packet error |
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* @skb: the packet |
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* @family: the packet's address family |
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* @error: the error code |
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* @gateway: true if host is acting as a gateway, false otherwise |
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* |
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* Description: |
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* When a packet is dropped due to a call to avc_has_perm() pass the error |
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* code to the NetLabel subsystem so any protocol specific processing can be |
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* done. This is safe to call even if you are unsure if NetLabel labeling is |
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* present on the packet, NetLabel is smart enough to only act when it should. |
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* |
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*/ |
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void selinux_netlbl_err(struct sk_buff *skb, u16 family, int error, int gateway) |
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{ |
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netlbl_skbuff_err(skb, family, error, gateway); |
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} |
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/** |
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* selinux_netlbl_sk_security_free - Free the NetLabel fields |
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* @sksec: the sk_security_struct |
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* |
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* Description: |
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* Free all of the memory in the NetLabel fields of a sk_security_struct. |
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* |
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*/ |
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void selinux_netlbl_sk_security_free(struct sk_security_struct *sksec) |
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{ |
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if (sksec->nlbl_secattr != NULL) |
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netlbl_secattr_free(sksec->nlbl_secattr); |
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} |
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/** |
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* selinux_netlbl_sk_security_reset - Reset the NetLabel fields |
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* @sksec: the sk_security_struct |
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* |
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* Description: |
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* Called when the NetLabel state of a sk_security_struct needs to be reset. |
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* The caller is responsible for all the NetLabel sk_security_struct locking. |
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* |
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*/ |
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void selinux_netlbl_sk_security_reset(struct sk_security_struct *sksec) |
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{ |
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sksec->nlbl_state = NLBL_UNSET; |
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} |
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/** |
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* selinux_netlbl_skbuff_getsid - Get the sid of a packet using NetLabel |
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* @skb: the packet |
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* @family: protocol family |
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* @type: NetLabel labeling protocol type |
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* @sid: the SID |
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* |
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* Description: |
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* Call the NetLabel mechanism to get the security attributes of the given |
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* packet and use those attributes to determine the correct context/SID to |
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* assign to the packet. Returns zero on success, negative values on failure. |
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* |
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*/ |
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int selinux_netlbl_skbuff_getsid(struct sk_buff *skb, |
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u16 family, |
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u32 *type, |
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u32 *sid) |
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{ |
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int rc; |
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struct netlbl_lsm_secattr secattr; |
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if (!netlbl_enabled()) { |
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*sid = SECSID_NULL; |
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return 0; |
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} |
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netlbl_secattr_init(&secattr); |
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rc = netlbl_skbuff_getattr(skb, family, &secattr); |
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if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) |
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rc = selinux_netlbl_sidlookup_cached(skb, family, |
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&secattr, sid); |
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else |
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*sid = SECSID_NULL; |
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*type = secattr.type; |
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netlbl_secattr_destroy(&secattr); |
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return rc; |
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} |
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/** |
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* selinux_netlbl_skbuff_setsid - Set the NetLabel on a packet given a sid |
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* @skb: the packet |
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* @family: protocol family |
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* @sid: the SID |
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* |
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* Description |
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* Call the NetLabel mechanism to set the label of a packet using @sid. |
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* Returns zero on success, negative values on failure. |
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* |
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*/ |
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int selinux_netlbl_skbuff_setsid(struct sk_buff *skb, |
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u16 family, |
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u32 sid) |
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{ |
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int rc; |
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struct netlbl_lsm_secattr secattr_storage; |
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struct netlbl_lsm_secattr *secattr = NULL; |
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struct sock *sk; |
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/* if this is a locally generated packet check to see if it is already |
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* being labeled by it's parent socket, if it is just exit */ |
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sk = skb_to_full_sk(skb); |
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if (sk != NULL) { |
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struct sk_security_struct *sksec = sk->sk_security; |
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if (sksec->nlbl_state != NLBL_REQSKB) |
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return 0; |
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secattr = selinux_netlbl_sock_getattr(sk, sid); |
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} |
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if (secattr == NULL) { |
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secattr = &secattr_storage; |
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netlbl_secattr_init(secattr); |
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rc = security_netlbl_sid_to_secattr(&selinux_state, sid, |
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secattr); |
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if (rc != 0) |
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goto skbuff_setsid_return; |
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} |
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rc = netlbl_skbuff_setattr(skb, family, secattr); |
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skbuff_setsid_return: |
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if (secattr == &secattr_storage) |
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netlbl_secattr_destroy(secattr); |
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return rc; |
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} |
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/** |
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* selinux_netlbl_sctp_assoc_request - Label an incoming sctp association. |
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* @asoc: incoming association. |
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* @skb: the packet. |
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* |
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* Description: |
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* A new incoming connection is represented by @asoc, ...... |
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* Returns zero on success, negative values on failure. |
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* |
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*/ |
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int selinux_netlbl_sctp_assoc_request(struct sctp_association *asoc, |
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struct sk_buff *skb) |
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{ |
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int rc; |
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struct netlbl_lsm_secattr secattr; |
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struct sk_security_struct *sksec = asoc->base.sk->sk_security; |
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struct sockaddr_in addr4; |
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struct sockaddr_in6 addr6; |
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if (asoc->base.sk->sk_family != PF_INET && |
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asoc->base.sk->sk_family != PF_INET6) |
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return 0; |
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netlbl_secattr_init(&secattr); |
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rc = security_netlbl_sid_to_secattr(&selinux_state, |
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asoc->secid, &secattr); |
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if (rc != 0) |
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goto assoc_request_return; |
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/* Move skb hdr address info to a struct sockaddr and then call |
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* netlbl_conn_setattr(). |
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*/ |
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if (ip_hdr(skb)->version == 4) { |
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addr4.sin_family = AF_INET; |
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addr4.sin_addr.s_addr = ip_hdr(skb)->saddr; |
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rc = netlbl_conn_setattr(asoc->base.sk, (void *)&addr4, &secattr); |
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} else if (IS_ENABLED(CONFIG_IPV6) && ip_hdr(skb)->version == 6) { |
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addr6.sin6_family = AF_INET6; |
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addr6.sin6_addr = ipv6_hdr(skb)->saddr; |
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rc = netlbl_conn_setattr(asoc->base.sk, (void *)&addr6, &secattr); |
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} else { |
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rc = -EAFNOSUPPORT; |
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} |
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if (rc == 0) |
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sksec->nlbl_state = NLBL_LABELED; |
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assoc_request_return: |
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netlbl_secattr_destroy(&secattr); |
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return rc; |
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} |
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/** |
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* selinux_netlbl_inet_conn_request - Label an incoming stream connection |
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* @req: incoming connection request socket |
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* @family: the request socket's address family |
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* |
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* Description: |
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* A new incoming connection request is represented by @req, we need to label |
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* the new request_sock here and the stack will ensure the on-the-wire label |
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* will get preserved when a full sock is created once the connection handshake |
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* is complete. Returns zero on success, negative values on failure. |
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* |
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*/ |
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int selinux_netlbl_inet_conn_request(struct request_sock *req, u16 family) |
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{ |
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int rc; |
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struct netlbl_lsm_secattr secattr; |
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if (family != PF_INET && family != PF_INET6) |
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return 0; |
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netlbl_secattr_init(&secattr); |
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rc = security_netlbl_sid_to_secattr(&selinux_state, req->secid, |
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&secattr); |
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if (rc != 0) |
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goto inet_conn_request_return; |
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rc = netlbl_req_setattr(req, &secattr); |
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inet_conn_request_return: |
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netlbl_secattr_destroy(&secattr); |
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return rc; |
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} |
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/** |
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* selinux_netlbl_inet_csk_clone - Initialize the newly created sock |
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* @sk: the new sock |
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* @family: the sock's address family |
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* |
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* Description: |
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* A new connection has been established using @sk, we've already labeled the |
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* socket via the request_sock struct in selinux_netlbl_inet_conn_request() but |
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* we need to set the NetLabel state here since we now have a sock structure. |
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* |
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*/ |
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void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family) |
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{ |
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struct sk_security_struct *sksec = sk->sk_security; |
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if (family == PF_INET) |
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sksec->nlbl_state = NLBL_LABELED; |
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else |
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sksec->nlbl_state = NLBL_UNSET; |
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} |
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/** |
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* selinux_netlbl_sctp_sk_clone - Copy state to the newly created sock |
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* @sk: current sock |
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* @newsk: the new sock |
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* |
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* Description: |
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* Called whenever a new socket is created by accept(2) or sctp_peeloff(3). |
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*/ |
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void selinux_netlbl_sctp_sk_clone(struct sock *sk, struct sock *newsk) |
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{ |
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struct sk_security_struct *sksec = sk->sk_security; |
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struct sk_security_struct *newsksec = newsk->sk_security; |
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newsksec->nlbl_state = sksec->nlbl_state; |
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} |
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/** |
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* selinux_netlbl_socket_post_create - Label a socket using NetLabel |
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* @sk: the sock to label |
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* @family: protocol family |
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* |
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* Description: |
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* Attempt to label a socket using the NetLabel mechanism using the given |
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* SID. Returns zero values on success, negative values on failure. |
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* |
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*/ |
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int selinux_netlbl_socket_post_create(struct sock *sk, u16 family) |
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{ |
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int rc; |
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struct sk_security_struct *sksec = sk->sk_security; |
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struct netlbl_lsm_secattr *secattr; |
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if (family != PF_INET && family != PF_INET6) |
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return 0; |
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secattr = selinux_netlbl_sock_genattr(sk); |
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if (secattr == NULL) |
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return -ENOMEM; |
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rc = netlbl_sock_setattr(sk, family, secattr); |
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switch (rc) { |
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case 0: |
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sksec->nlbl_state = NLBL_LABELED; |
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break; |
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case -EDESTADDRREQ: |
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sksec->nlbl_state = NLBL_REQSKB; |
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rc = 0; |
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break; |
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} |
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return rc; |
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} |
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/** |
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* selinux_netlbl_sock_rcv_skb - Do an inbound access check using NetLabel |
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* @sksec: the sock's sk_security_struct |
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* @skb: the packet |
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* @family: protocol family |
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* @ad: the audit data |
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* |
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* Description: |
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* Fetch the NetLabel security attributes from @skb and perform an access check |
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* against the receiving socket. Returns zero on success, negative values on |
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* error. |
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* |
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*/ |
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int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec, |
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struct sk_buff *skb, |
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u16 family, |
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struct common_audit_data *ad) |
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{ |
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int rc; |
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u32 nlbl_sid; |
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u32 perm; |
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struct netlbl_lsm_secattr secattr; |
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if (!netlbl_enabled()) |
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return 0; |
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netlbl_secattr_init(&secattr); |
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rc = netlbl_skbuff_getattr(skb, family, &secattr); |
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if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) |
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rc = selinux_netlbl_sidlookup_cached(skb, family, |
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&secattr, &nlbl_sid); |
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else |
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nlbl_sid = SECINITSID_UNLABELED; |
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netlbl_secattr_destroy(&secattr); |
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if (rc != 0) |
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return rc; |
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switch (sksec->sclass) { |
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case SECCLASS_UDP_SOCKET: |
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perm = UDP_SOCKET__RECVFROM; |
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break; |
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case SECCLASS_TCP_SOCKET: |
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perm = TCP_SOCKET__RECVFROM; |
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break; |
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default: |
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perm = RAWIP_SOCKET__RECVFROM; |
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} |
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rc = avc_has_perm(&selinux_state, |
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sksec->sid, nlbl_sid, sksec->sclass, perm, ad); |
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if (rc == 0) |
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return 0; |
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|
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if (nlbl_sid != SECINITSID_UNLABELED) |
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netlbl_skbuff_err(skb, family, rc, 0); |
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return rc; |
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} |
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|
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/** |
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* selinux_netlbl_option - Is this a NetLabel option |
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* @level: the socket level or protocol |
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* @optname: the socket option name |
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* |
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* Description: |
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* Returns true if @level and @optname refer to a NetLabel option. |
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* Helper for selinux_netlbl_socket_setsockopt(). |
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*/ |
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static inline int selinux_netlbl_option(int level, int optname) |
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{ |
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return (level == IPPROTO_IP && optname == IP_OPTIONS) || |
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(level == IPPROTO_IPV6 && optname == IPV6_HOPOPTS); |
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} |
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|
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/** |
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* selinux_netlbl_socket_setsockopt - Do not allow users to remove a NetLabel |
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* @sock: the socket |
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* @level: the socket level or protocol |
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* @optname: the socket option name |
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* |
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* Description: |
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* Check the setsockopt() call and if the user is trying to replace the IP |
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* options on a socket and a NetLabel is in place for the socket deny the |
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* access; otherwise allow the access. Returns zero when the access is |
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* allowed, -EACCES when denied, and other negative values on error. |
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* |
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*/ |
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int selinux_netlbl_socket_setsockopt(struct socket *sock, |
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int level, |
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int optname) |
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{ |
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int rc = 0; |
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struct sock *sk = sock->sk; |
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struct sk_security_struct *sksec = sk->sk_security; |
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struct netlbl_lsm_secattr secattr; |
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|
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if (selinux_netlbl_option(level, optname) && |
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(sksec->nlbl_state == NLBL_LABELED || |
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sksec->nlbl_state == NLBL_CONNLABELED)) { |
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netlbl_secattr_init(&secattr); |
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lock_sock(sk); |
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/* call the netlabel function directly as we want to see the |
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* on-the-wire label that is assigned via the socket's options |
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* and not the cached netlabel/lsm attributes */ |
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rc = netlbl_sock_getattr(sk, &secattr); |
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release_sock(sk); |
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if (rc == 0) |
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rc = -EACCES; |
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else if (rc == -ENOMSG) |
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rc = 0; |
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netlbl_secattr_destroy(&secattr); |
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} |
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|
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return rc; |
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} |
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|
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/** |
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* selinux_netlbl_socket_connect_helper - Help label a client-side socket on |
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* connect |
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* @sk: the socket to label |
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* @addr: the destination address |
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* |
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* Description: |
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* Attempt to label a connected socket with NetLabel using the given address. |
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* Returns zero values on success, negative values on failure. |
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* |
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*/ |
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static int selinux_netlbl_socket_connect_helper(struct sock *sk, |
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struct sockaddr *addr) |
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{ |
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int rc; |
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struct sk_security_struct *sksec = sk->sk_security; |
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struct netlbl_lsm_secattr *secattr; |
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|
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/* connected sockets are allowed to disconnect when the address family |
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* is set to AF_UNSPEC, if that is what is happening we want to reset |
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* the socket */ |
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if (addr->sa_family == AF_UNSPEC) { |
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netlbl_sock_delattr(sk); |
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sksec->nlbl_state = NLBL_REQSKB; |
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rc = 0; |
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return rc; |
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} |
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secattr = selinux_netlbl_sock_genattr(sk); |
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if (secattr == NULL) { |
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rc = -ENOMEM; |
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return rc; |
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} |
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rc = netlbl_conn_setattr(sk, addr, secattr); |
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if (rc == 0) |
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sksec->nlbl_state = NLBL_CONNLABELED; |
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|
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return rc; |
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} |
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|
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/** |
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* selinux_netlbl_socket_connect_locked - Label a client-side socket on |
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* connect |
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* @sk: the socket to label |
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* @addr: the destination address |
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* |
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* Description: |
|
* Attempt to label a connected socket that already has the socket locked |
|
* with NetLabel using the given address. |
|
* Returns zero values on success, negative values on failure. |
|
* |
|
*/ |
|
int selinux_netlbl_socket_connect_locked(struct sock *sk, |
|
struct sockaddr *addr) |
|
{ |
|
struct sk_security_struct *sksec = sk->sk_security; |
|
|
|
if (sksec->nlbl_state != NLBL_REQSKB && |
|
sksec->nlbl_state != NLBL_CONNLABELED) |
|
return 0; |
|
|
|
return selinux_netlbl_socket_connect_helper(sk, addr); |
|
} |
|
|
|
/** |
|
* selinux_netlbl_socket_connect - Label a client-side socket on connect |
|
* @sk: the socket to label |
|
* @addr: the destination address |
|
* |
|
* Description: |
|
* Attempt to label a connected socket with NetLabel using the given address. |
|
* Returns zero values on success, negative values on failure. |
|
* |
|
*/ |
|
int selinux_netlbl_socket_connect(struct sock *sk, struct sockaddr *addr) |
|
{ |
|
int rc; |
|
|
|
lock_sock(sk); |
|
rc = selinux_netlbl_socket_connect_locked(sk, addr); |
|
release_sock(sk); |
|
|
|
return rc; |
|
}
|
|
|