From d452930fd3b9031e59abfeddb2fa383f1403d61a Mon Sep 17 00:00:00 2001 From: Richard Haines Date: Tue, 13 Feb 2018 20:57:18 +0000 Subject: selinux: Add SCTP support The SELinux SCTP implementation is explained in: Documentation/security/SELinux-sctp.rst Signed-off-by: Richard Haines Signed-off-by: Paul Moore --- security/selinux/hooks.c | 280 +++++++++++++++++++++++++++++++++--- security/selinux/include/classmap.h | 2 +- security/selinux/include/netlabel.h | 21 ++- security/selinux/include/objsec.h | 4 + security/selinux/netlabel.c | 133 +++++++++++++++-- 5 files changed, 408 insertions(+), 32 deletions(-) (limited to 'security') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 8644d864e3c1..28a5c4ee0705 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -67,6 +67,8 @@ #include #include #include +#include +#include #include #include /* for Unix socket types */ #include /* for Unix socket types */ @@ -4134,6 +4136,23 @@ static int selinux_parse_skb_ipv4(struct sk_buff *skb, break; } +#if IS_ENABLED(CONFIG_IP_SCTP) + case IPPROTO_SCTP: { + struct sctphdr _sctph, *sh; + + if (ntohs(ih->frag_off) & IP_OFFSET) + break; + + offset += ihlen; + sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph); + if (sh == NULL) + break; + + ad->u.net->sport = sh->source; + ad->u.net->dport = sh->dest; + break; + } +#endif default: break; } @@ -4207,6 +4226,19 @@ static int selinux_parse_skb_ipv6(struct sk_buff *skb, break; } +#if IS_ENABLED(CONFIG_IP_SCTP) + case IPPROTO_SCTP: { + struct sctphdr _sctph, *sh; + + sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph); + if (sh == NULL) + break; + + ad->u.net->sport = sh->source; + ad->u.net->dport = sh->dest; + break; + } +#endif /* includes fragments */ default: break; @@ -4396,6 +4428,10 @@ static int selinux_socket_post_create(struct socket *sock, int family, sksec = sock->sk->sk_security; sksec->sclass = sclass; sksec->sid = sid; + /* Allows detection of the first association on this socket */ + if (sksec->sclass == SECCLASS_SCTP_SOCKET) + sksec->sctp_assoc_state = SCTP_ASSOC_UNSET; + err = selinux_netlbl_socket_post_create(sock->sk, family); } @@ -4416,11 +4452,7 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in if (err) goto out; - /* - * If PF_INET or PF_INET6, check name_bind permission for the port. - * Multiple address binding for SCTP is not supported yet: we just - * check the first address now. - */ + /* If PF_INET or PF_INET6, check name_bind permission for the port. */ family = sk->sk_family; if (family == PF_INET || family == PF_INET6) { char *addrp; @@ -4432,7 +4464,13 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in unsigned short snum; u32 sid, node_perm; - if (family == PF_INET) { + /* + * sctp_bindx(3) calls via selinux_sctp_bind_connect() + * that validates multiple binding addresses. Because of this + * need to check address->sa_family as it is possible to have + * sk->sk_family = PF_INET6 with addr->sa_family = AF_INET. + */ + if (address->sa_family == AF_INET) { if (addrlen < sizeof(struct sockaddr_in)) { err = -EINVAL; goto out; @@ -4486,6 +4524,10 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in node_perm = DCCP_SOCKET__NODE_BIND; break; + case SECCLASS_SCTP_SOCKET: + node_perm = SCTP_SOCKET__NODE_BIND; + break; + default: node_perm = RAWIP_SOCKET__NODE_BIND; break; @@ -4500,7 +4542,7 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in ad.u.net->sport = htons(snum); ad.u.net->family = family; - if (family == PF_INET) + if (address->sa_family == AF_INET) ad.u.net->v4info.saddr = addr4->sin_addr.s_addr; else ad.u.net->v6info.saddr = addr6->sin6_addr; @@ -4514,7 +4556,11 @@ out: return err; } -static int selinux_socket_connect(struct socket *sock, struct sockaddr *address, int addrlen) +/* This supports connect(2) and SCTP connect services such as sctp_connectx(3) + * and sctp_sendmsg(3) as described in Documentation/security/LSM-sctp.txt + */ +static int selinux_socket_connect_helper(struct socket *sock, + struct sockaddr *address, int addrlen) { struct sock *sk = sock->sk; struct sk_security_struct *sksec = sk->sk_security; @@ -4525,10 +4571,12 @@ static int selinux_socket_connect(struct socket *sock, struct sockaddr *address, return err; /* - * If a TCP or DCCP socket, check name_connect permission for the port. + * If a TCP, DCCP or SCTP socket, check name_connect permission + * for the port. */ if (sksec->sclass == SECCLASS_TCP_SOCKET || - sksec->sclass == SECCLASS_DCCP_SOCKET) { + sksec->sclass == SECCLASS_DCCP_SOCKET || + sksec->sclass == SECCLASS_SCTP_SOCKET) { struct common_audit_data ad; struct lsm_network_audit net = {0,}; struct sockaddr_in *addr4 = NULL; @@ -4536,7 +4584,12 @@ static int selinux_socket_connect(struct socket *sock, struct sockaddr *address, unsigned short snum; u32 sid, perm; - if (sk->sk_family == PF_INET) { + /* sctp_connectx(3) calls via selinux_sctp_bind_connect() + * that validates multiple connect addresses. Because of this + * need to check address->sa_family as it is possible to have + * sk->sk_family = PF_INET6 with addr->sa_family = AF_INET. + */ + if (address->sa_family == AF_INET) { addr4 = (struct sockaddr_in *)address; if (addrlen < sizeof(struct sockaddr_in)) return -EINVAL; @@ -4550,10 +4603,19 @@ static int selinux_socket_connect(struct socket *sock, struct sockaddr *address, err = sel_netport_sid(sk->sk_protocol, snum, &sid); if (err) - goto out; + return err; - perm = (sksec->sclass == SECCLASS_TCP_SOCKET) ? - TCP_SOCKET__NAME_CONNECT : DCCP_SOCKET__NAME_CONNECT; + switch (sksec->sclass) { + case SECCLASS_TCP_SOCKET: + perm = TCP_SOCKET__NAME_CONNECT; + break; + case SECCLASS_DCCP_SOCKET: + perm = DCCP_SOCKET__NAME_CONNECT; + break; + case SECCLASS_SCTP_SOCKET: + perm = SCTP_SOCKET__NAME_CONNECT; + break; + } ad.type = LSM_AUDIT_DATA_NET; ad.u.net = &net; @@ -4561,13 +4623,24 @@ static int selinux_socket_connect(struct socket *sock, struct sockaddr *address, ad.u.net->family = sk->sk_family; err = avc_has_perm(sksec->sid, sid, sksec->sclass, perm, &ad); if (err) - goto out; + return err; } - err = selinux_netlbl_socket_connect(sk, address); + return 0; +} -out: - return err; +/* Supports connect(2), see comments in selinux_socket_connect_helper() */ +static int selinux_socket_connect(struct socket *sock, + struct sockaddr *address, int addrlen) +{ + int err; + struct sock *sk = sock->sk; + + err = selinux_socket_connect_helper(sock, address, addrlen); + if (err) + return err; + + return selinux_netlbl_socket_connect(sk, address); } static int selinux_socket_listen(struct socket *sock, int backlog) @@ -4830,7 +4903,8 @@ static int selinux_socket_getpeersec_stream(struct socket *sock, char __user *op u32 peer_sid = SECSID_NULL; if (sksec->sclass == SECCLASS_UNIX_STREAM_SOCKET || - sksec->sclass == SECCLASS_TCP_SOCKET) + sksec->sclass == SECCLASS_TCP_SOCKET || + sksec->sclass == SECCLASS_SCTP_SOCKET) peer_sid = sksec->peer_sid; if (peer_sid == SECSID_NULL) return -ENOPROTOOPT; @@ -4943,6 +5017,171 @@ static void selinux_sock_graft(struct sock *sk, struct socket *parent) sksec->sclass = isec->sclass; } +/* Called whenever SCTP receives an INIT chunk. This happens when an incoming + * connect(2), sctp_connectx(3) or sctp_sendmsg(3) (with no association + * already present). + */ +static int selinux_sctp_assoc_request(struct sctp_endpoint *ep, + struct sk_buff *skb) +{ + struct sk_security_struct *sksec = ep->base.sk->sk_security; + struct common_audit_data ad; + struct lsm_network_audit net = {0,}; + u8 peerlbl_active; + u32 peer_sid = SECINITSID_UNLABELED; + u32 conn_sid; + int err = 0; + + if (!selinux_policycap_extsockclass) + return 0; + + peerlbl_active = selinux_peerlbl_enabled(); + + if (peerlbl_active) { + /* This will return peer_sid = SECSID_NULL if there are + * no peer labels, see security_net_peersid_resolve(). + */ + err = selinux_skb_peerlbl_sid(skb, ep->base.sk->sk_family, + &peer_sid); + if (err) + return err; + + if (peer_sid == SECSID_NULL) + peer_sid = SECINITSID_UNLABELED; + } + + if (sksec->sctp_assoc_state == SCTP_ASSOC_UNSET) { + sksec->sctp_assoc_state = SCTP_ASSOC_SET; + + /* Here as first association on socket. As the peer SID + * was allowed by peer recv (and the netif/node checks), + * then it is approved by policy and used as the primary + * peer SID for getpeercon(3). + */ + sksec->peer_sid = peer_sid; + } else if (sksec->peer_sid != peer_sid) { + /* Other association peer SIDs are checked to enforce + * consistency among the peer SIDs. + */ + ad.type = LSM_AUDIT_DATA_NET; + ad.u.net = &net; + ad.u.net->sk = ep->base.sk; + err = avc_has_perm(sksec->peer_sid, peer_sid, sksec->sclass, + SCTP_SOCKET__ASSOCIATION, &ad); + if (err) + return err; + } + + /* Compute the MLS component for the connection and store + * the information in ep. This will be used by SCTP TCP type + * sockets and peeled off connections as they cause a new + * socket to be generated. selinux_sctp_sk_clone() will then + * plug this into the new socket. + */ + err = selinux_conn_sid(sksec->sid, peer_sid, &conn_sid); + if (err) + return err; + + ep->secid = conn_sid; + ep->peer_secid = peer_sid; + + /* Set any NetLabel labels including CIPSO/CALIPSO options. */ + return selinux_netlbl_sctp_assoc_request(ep, skb); +} + +/* Check if sctp IPv4/IPv6 addresses are valid for binding or connecting + * based on their @optname. + */ +static int selinux_sctp_bind_connect(struct sock *sk, int optname, + struct sockaddr *address, + int addrlen) +{ + int len, err = 0, walk_size = 0; + void *addr_buf; + struct sockaddr *addr; + struct socket *sock; + + if (!selinux_policycap_extsockclass) + return 0; + + /* Process one or more addresses that may be IPv4 or IPv6 */ + sock = sk->sk_socket; + addr_buf = address; + + while (walk_size < addrlen) { + addr = addr_buf; + switch (addr->sa_family) { + case AF_INET: + len = sizeof(struct sockaddr_in); + break; + case AF_INET6: + len = sizeof(struct sockaddr_in6); + break; + default: + return -EAFNOSUPPORT; + } + + err = -EINVAL; + switch (optname) { + /* Bind checks */ + case SCTP_PRIMARY_ADDR: + case SCTP_SET_PEER_PRIMARY_ADDR: + case SCTP_SOCKOPT_BINDX_ADD: + err = selinux_socket_bind(sock, addr, len); + break; + /* Connect checks */ + case SCTP_SOCKOPT_CONNECTX: + case SCTP_PARAM_SET_PRIMARY: + case SCTP_PARAM_ADD_IP: + case SCTP_SENDMSG_CONNECT: + err = selinux_socket_connect_helper(sock, addr, len); + if (err) + return err; + + /* As selinux_sctp_bind_connect() is called by the + * SCTP protocol layer, the socket is already locked, + * therefore selinux_netlbl_socket_connect_locked() is + * is called here. The situations handled are: + * sctp_connectx(3), sctp_sendmsg(3), sendmsg(2), + * whenever a new IP address is added or when a new + * primary address is selected. + * Note that an SCTP connect(2) call happens before + * the SCTP protocol layer and is handled via + * selinux_socket_connect(). + */ + err = selinux_netlbl_socket_connect_locked(sk, addr); + break; + } + + if (err) + return err; + + addr_buf += len; + walk_size += len; + } + + return 0; +} + +/* Called whenever a new socket is created by accept(2) or sctp_peeloff(3). */ +static void selinux_sctp_sk_clone(struct sctp_endpoint *ep, struct sock *sk, + struct sock *newsk) +{ + struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *newsksec = newsk->sk_security; + + /* If policy does not support SECCLASS_SCTP_SOCKET then call + * the non-sctp clone version. + */ + if (!selinux_policycap_extsockclass) + return selinux_sk_clone_security(sk, newsk); + + newsksec->sid = ep->secid; + newsksec->peer_sid = ep->peer_secid; + newsksec->sclass = sksec->sclass; + selinux_netlbl_sctp_sk_clone(sk, newsk); +} + static int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb, struct request_sock *req) { @@ -6563,6 +6802,9 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(sk_clone_security, selinux_sk_clone_security), LSM_HOOK_INIT(sk_getsecid, selinux_sk_getsecid), LSM_HOOK_INIT(sock_graft, selinux_sock_graft), + LSM_HOOK_INIT(sctp_assoc_request, selinux_sctp_assoc_request), + LSM_HOOK_INIT(sctp_sk_clone, selinux_sctp_sk_clone), + LSM_HOOK_INIT(sctp_bind_connect, selinux_sctp_bind_connect), LSM_HOOK_INIT(inet_conn_request, selinux_inet_conn_request), LSM_HOOK_INIT(inet_csk_clone, selinux_inet_csk_clone), LSM_HOOK_INIT(inet_conn_established, selinux_inet_conn_established), diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h index acdee7795297..7f0372426494 100644 --- a/security/selinux/include/classmap.h +++ b/security/selinux/include/classmap.h @@ -176,7 +176,7 @@ struct security_class_mapping secclass_map[] = { { COMMON_CAP2_PERMS, NULL } }, { "sctp_socket", { COMMON_SOCK_PERMS, - "node_bind", NULL } }, + "node_bind", "name_connect", "association", NULL } }, { "icmp_socket", { COMMON_SOCK_PERMS, "node_bind", NULL } }, diff --git a/security/selinux/include/netlabel.h b/security/selinux/include/netlabel.h index e77a5e307955..6ef4953431dc 100644 --- a/security/selinux/include/netlabel.h +++ b/security/selinux/include/netlabel.h @@ -32,6 +32,7 @@ #include #include #include +#include #include "avc.h" #include "objsec.h" @@ -52,9 +53,11 @@ int selinux_netlbl_skbuff_getsid(struct sk_buff *skb, int selinux_netlbl_skbuff_setsid(struct sk_buff *skb, u16 family, u32 sid); - +int selinux_netlbl_sctp_assoc_request(struct sctp_endpoint *ep, + struct sk_buff *skb); int selinux_netlbl_inet_conn_request(struct request_sock *req, u16 family); void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family); +void selinux_netlbl_sctp_sk_clone(struct sock *sk, struct sock *newsk); int selinux_netlbl_socket_post_create(struct sock *sk, u16 family); int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec, struct sk_buff *skb, @@ -64,6 +67,8 @@ int selinux_netlbl_socket_setsockopt(struct socket *sock, int level, int optname); int selinux_netlbl_socket_connect(struct sock *sk, struct sockaddr *addr); +int selinux_netlbl_socket_connect_locked(struct sock *sk, + struct sockaddr *addr); #else static inline void selinux_netlbl_cache_invalidate(void) @@ -113,6 +118,11 @@ static inline int selinux_netlbl_conn_setsid(struct sock *sk, return 0; } +static inline int selinux_netlbl_sctp_assoc_request(struct sctp_endpoint *ep, + struct sk_buff *skb) +{ + return 0; +} static inline int selinux_netlbl_inet_conn_request(struct request_sock *req, u16 family) { @@ -122,6 +132,10 @@ static inline void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family) { return; } +static inline void selinux_netlbl_sctp_sk_clone(struct sock *sk, sock *newsk) +{ + return; +} static inline int selinux_netlbl_socket_post_create(struct sock *sk, u16 family) { @@ -145,6 +159,11 @@ static inline int selinux_netlbl_socket_connect(struct sock *sk, { return 0; } +static inline int selinux_netlbl_socket_connect_locked(struct sock *sk, + struct sockaddr *addr) +{ + return 0; +} #endif /* CONFIG_NETLABEL */ #endif diff --git a/security/selinux/include/objsec.h b/security/selinux/include/objsec.h index 3d54468ce334..dabf02888a95 100644 --- a/security/selinux/include/objsec.h +++ b/security/selinux/include/objsec.h @@ -130,6 +130,10 @@ struct sk_security_struct { u32 sid; /* SID of this object */ u32 peer_sid; /* SID of peer */ u16 sclass; /* sock security class */ + enum { /* SCTP association state */ + SCTP_ASSOC_UNSET = 0, + SCTP_ASSOC_SET, + } sctp_assoc_state; }; struct tun_security_struct { diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c index 2c297b995b16..8730be427390 100644 --- a/security/selinux/netlabel.c +++ b/security/selinux/netlabel.c @@ -249,6 +249,7 @@ int selinux_netlbl_skbuff_setsid(struct sk_buff *skb, 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); @@ -269,6 +270,61 @@ skbuff_setsid_return: return rc; } +/** + * selinux_netlbl_sctp_assoc_request - Label an incoming sctp association. + * @ep: incoming association endpoint. + * @skb: the packet. + * + * Description: + * A new incoming connection is represented by @ep, ...... + * Returns zero on success, negative values on failure. + * + */ +int selinux_netlbl_sctp_assoc_request(struct sctp_endpoint *ep, + struct sk_buff *skb) +{ + int rc; + struct netlbl_lsm_secattr secattr; + struct sk_security_struct *sksec = ep->base.sk->sk_security; + struct sockaddr *addr; + struct sockaddr_in addr4; +#if IS_ENABLED(CONFIG_IPV6) + struct sockaddr_in6 addr6; +#endif + + if (ep->base.sk->sk_family != PF_INET && + ep->base.sk->sk_family != PF_INET6) + return 0; + + netlbl_secattr_init(&secattr); + rc = security_netlbl_sid_to_secattr(ep->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; + addr = (struct sockaddr *)&addr4; +#if IS_ENABLED(CONFIG_IPV6) + } else { + addr6.sin6_family = AF_INET6; + addr6.sin6_addr = ipv6_hdr(skb)->saddr; + addr = (struct sockaddr *)&addr6; +#endif + } + + rc = netlbl_conn_setattr(ep->base.sk, addr, &secattr); + 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 @@ -318,6 +374,22 @@ void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family) 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 * @sock: the socket to label @@ -469,7 +541,8 @@ int selinux_netlbl_socket_setsockopt(struct socket *sock, } /** - * selinux_netlbl_socket_connect - Label a client-side socket on connect + * selinux_netlbl_socket_connect_helper - Help label a client-side socket on + * connect * @sk: the socket to label * @addr: the destination address * @@ -478,18 +551,13 @@ int selinux_netlbl_socket_setsockopt(struct socket *sock, * Returns zero values on success, negative values on failure. * */ -int selinux_netlbl_socket_connect(struct sock *sk, struct sockaddr *addr) +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; - if (sksec->nlbl_state != NLBL_REQSKB && - sksec->nlbl_state != NLBL_CONNLABELED) - return 0; - - lock_sock(sk); - /* 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 */ @@ -497,18 +565,61 @@ int selinux_netlbl_socket_connect(struct sock *sk, struct sockaddr *addr) netlbl_sock_delattr(sk); sksec->nlbl_state = NLBL_REQSKB; rc = 0; - goto socket_connect_return; + return rc; } secattr = selinux_netlbl_sock_genattr(sk); if (secattr == NULL) { rc = -ENOMEM; - goto socket_connect_return; + return rc; } rc = netlbl_conn_setattr(sk, addr, secattr); if (rc == 0) sksec->nlbl_state = NLBL_CONNLABELED; -socket_connect_return: + 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; } -- cgit v1.2.3