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