From 23bcdc1adebd3cb47d5666f2e9ecada95c0134e4 Mon Sep 17 00:00:00 2001 From: Paul Moore Date: Wed, 18 Jul 2007 12:28:45 -0400 Subject: SELinux: enable dynamic activation/deactivation of NetLabel/SELinux enforcement Create a new NetLabel KAPI interface, netlbl_enabled(), which reports on the current runtime status of NetLabel based on the existing configuration. LSMs that make use of NetLabel, i.e. SELinux, can use this new function to determine if they should perform NetLabel access checks. This patch changes the NetLabel/SELinux glue code such that SELinux only enforces NetLabel related access checks when netlbl_enabled() returns true. At present NetLabel is considered to be enabled when there is at least one labeled protocol configuration present. The result is that by default NetLabel is considered to be disabled, however, as soon as an administrator configured a CIPSO DOI definition NetLabel is enabled and SELinux starts enforcing NetLabel related access controls - including unlabeled packet controls. This patch also tries to consolidate the multiple "#ifdef CONFIG_NETLABEL" blocks into a single block to ease future review as recommended by Linus. Signed-off-by: Paul Moore Signed-off-by: James Morris --- security/selinux/netlabel.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'security') diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c index e64eca246f1a..ed9155b29c1a 100644 --- a/security/selinux/netlabel.c +++ b/security/selinux/netlabel.c @@ -155,6 +155,11 @@ int selinux_netlbl_skbuff_getsid(struct sk_buff *skb, u32 base_sid, 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, &secattr); if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) @@ -298,6 +303,9 @@ int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec, u32 netlbl_sid; u32 recv_perm; + if (!netlbl_enabled()) + return 0; + rc = selinux_netlbl_skbuff_getsid(skb, SECINITSID_UNLABELED, &netlbl_sid); -- cgit v1.2.3-58-ga151 From f36158c410651fe66f438c17b2ab3ae813f8c060 Mon Sep 17 00:00:00 2001 From: Paul Moore Date: Wed, 18 Jul 2007 12:28:46 -0400 Subject: SELinux: use SECINITSID_NETMSG instead of SECINITSID_UNLABELED for NetLabel These changes will make NetLabel behave like labeled IPsec where there is an access check for both labeled and unlabeled packets as well as providing the ability to restrict domains to receiving only labeled packets when NetLabel is in use. The changes to the policy are straight forward with the following necessary to receive labeled traffic (with SECINITSID_NETMSG defined as "netlabel_peer_t"): allow mydom_t netlabel_peer_t:{ tcp_socket udp_socket rawip_socket } recvfrom; The policy for unlabeled traffic would be: allow mydom_t unlabeled_t:{ tcp_socket udp_socket rawip_socket } recvfrom; These policy changes, as well as more general NetLabel support, are included in the latest SELinux Reference Policy release 20070629 or later. Users who make use of NetLabel are strongly encouraged to upgrade their policy to avoid network problems. Users who do not make use of NetLabel will not notice any difference. Signed-off-by: Paul Moore Signed-off-by: James Morris --- security/selinux/hooks.c | 21 +++++++++++---------- security/selinux/netlabel.c | 41 ++++++++++++++++++++--------------------- 2 files changed, 31 insertions(+), 31 deletions(-) (limited to 'security') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 520b9998123e..26356e67108e 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3129,17 +3129,19 @@ static int selinux_parse_skb(struct sk_buff *skb, struct avc_audit_data *ad, /** * selinux_skb_extlbl_sid - Determine the external label of a packet * @skb: the packet - * @base_sid: the SELinux SID to use as a context for MLS only external labels * @sid: the packet's SID * * Description: * Check the various different forms of external packet labeling and determine - * the external SID for the packet. + * the external SID for the packet. If only one form of external labeling is + * present then it is used, if both labeled IPsec and NetLabel labels are + * present then the SELinux type information is taken from the labeled IPsec + * SA and the MLS sensitivity label information is taken from the NetLabel + * security attributes. This bit of "magic" is done in the call to + * selinux_netlbl_skbuff_getsid(). * */ -static void selinux_skb_extlbl_sid(struct sk_buff *skb, - u32 base_sid, - u32 *sid) +static void selinux_skb_extlbl_sid(struct sk_buff *skb, u32 *sid) { u32 xfrm_sid; u32 nlbl_sid; @@ -3147,10 +3149,9 @@ static void selinux_skb_extlbl_sid(struct sk_buff *skb, selinux_skb_xfrm_sid(skb, &xfrm_sid); if (selinux_netlbl_skbuff_getsid(skb, (xfrm_sid == SECSID_NULL ? - base_sid : xfrm_sid), + SECINITSID_NETMSG : xfrm_sid), &nlbl_sid) != 0) nlbl_sid = SECSID_NULL; - *sid = (nlbl_sid == SECSID_NULL ? xfrm_sid : nlbl_sid); } @@ -3695,7 +3696,7 @@ static int selinux_socket_getpeersec_dgram(struct socket *sock, struct sk_buff * if (sock && sock->sk->sk_family == PF_UNIX) selinux_get_inode_sid(SOCK_INODE(sock), &peer_secid); else if (skb) - selinux_skb_extlbl_sid(skb, SECINITSID_UNLABELED, &peer_secid); + selinux_skb_extlbl_sid(skb, &peer_secid); if (peer_secid == SECSID_NULL) err = -EINVAL; @@ -3756,7 +3757,7 @@ static int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb, u32 newsid; u32 peersid; - selinux_skb_extlbl_sid(skb, SECINITSID_UNLABELED, &peersid); + selinux_skb_extlbl_sid(skb, &peersid); if (peersid == SECSID_NULL) { req->secid = sksec->sid; req->peer_secid = SECSID_NULL; @@ -3794,7 +3795,7 @@ static void selinux_inet_conn_established(struct sock *sk, { struct sk_security_struct *sksec = sk->sk_security; - selinux_skb_extlbl_sid(skb, SECINITSID_UNLABELED, &sksec->peer_sid); + selinux_skb_extlbl_sid(skb, &sksec->peer_sid); } static void selinux_req_classify_flow(const struct request_sock *req, diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c index ed9155b29c1a..051b14c88e2d 100644 --- a/security/selinux/netlabel.c +++ b/security/selinux/netlabel.c @@ -163,9 +163,7 @@ int selinux_netlbl_skbuff_getsid(struct sk_buff *skb, u32 base_sid, u32 *sid) netlbl_secattr_init(&secattr); rc = netlbl_skbuff_getattr(skb, &secattr); if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) - rc = security_netlbl_secattr_to_sid(&secattr, - base_sid, - sid); + rc = security_netlbl_secattr_to_sid(&secattr, base_sid, sid); else *sid = SECSID_NULL; netlbl_secattr_destroy(&secattr); @@ -203,7 +201,7 @@ void selinux_netlbl_sock_graft(struct sock *sk, struct socket *sock) if (netlbl_sock_getattr(sk, &secattr) == 0 && secattr.flags != NETLBL_SECATTR_NONE && security_netlbl_secattr_to_sid(&secattr, - SECINITSID_UNLABELED, + SECINITSID_NETMSG, &nlbl_peer_sid) == 0) sksec->peer_sid = nlbl_peer_sid; netlbl_secattr_destroy(&secattr); @@ -300,41 +298,42 @@ int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec, struct avc_audit_data *ad) { int rc; - u32 netlbl_sid; - u32 recv_perm; + u32 nlbl_sid; + u32 perm; + struct netlbl_lsm_secattr secattr; if (!netlbl_enabled()) return 0; - rc = selinux_netlbl_skbuff_getsid(skb, - SECINITSID_UNLABELED, - &netlbl_sid); + netlbl_secattr_init(&secattr); + rc = netlbl_skbuff_getattr(skb, &secattr); + if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) + rc = security_netlbl_secattr_to_sid(&secattr, + SECINITSID_NETMSG, + &nlbl_sid); + else + nlbl_sid = SECINITSID_UNLABELED; + netlbl_secattr_destroy(&secattr); if (rc != 0) return rc; - if (netlbl_sid == SECSID_NULL) - return 0; - switch (sksec->sclass) { case SECCLASS_UDP_SOCKET: - recv_perm = UDP_SOCKET__RECVFROM; + perm = UDP_SOCKET__RECVFROM; break; case SECCLASS_TCP_SOCKET: - recv_perm = TCP_SOCKET__RECVFROM; + perm = TCP_SOCKET__RECVFROM; break; default: - recv_perm = RAWIP_SOCKET__RECVFROM; + perm = RAWIP_SOCKET__RECVFROM; } - rc = avc_has_perm(sksec->sid, - netlbl_sid, - sksec->sclass, - recv_perm, - ad); + rc = avc_has_perm(sksec->sid, nlbl_sid, sksec->sclass, perm, ad); if (rc == 0) return 0; - netlbl_skbuff_err(skb, rc); + if (nlbl_sid != SECINITSID_UNLABELED) + netlbl_skbuff_err(skb, rc); return rc; } -- cgit v1.2.3-58-ga151