* Authors: Serge Hallyn <sergeh@us.ibm.com>
* Trent Jaeger <jaegert@us.ibm.com>
*
+ * Updated: Venkat Yekkirala <vyekkirala@TrustedCS.com>
+ *
+ * Granular IPSec Associations for use in MLS environments.
+ *
* Copyright (C) 2005 International Business Machines Corporation
+ * Copyright (C) 2006 Trusted Computer Solutions, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2,
}
/*
- * LSM hook implementation that authorizes that a socket can be used
- * with the corresponding xfrm_sec_ctx and direction.
+ * LSM hook implementation that authorizes that a flow can use
+ * a xfrm policy rule.
*/
-int selinux_xfrm_policy_lookup(struct xfrm_policy *xp, u32 sk_sid, u8 dir)
+int selinux_xfrm_policy_lookup(struct xfrm_policy *xp, u32 fl_secid, u8 dir)
{
- int rc = 0;
- u32 sel_sid = SECINITSID_UNLABELED;
+ int rc;
+ u32 sel_sid;
struct xfrm_sec_ctx *ctx;
/* Context sid is either set to label or ANY_ASSOC */
sel_sid = ctx->ctx_sid;
}
+ else
+ /*
+ * All flows should be treated as polmatch'ing an
+ * otherwise applicable "non-labeled" policy. This
+ * would prevent inadvertent "leaks".
+ */
+ return 0;
- rc = avc_has_perm(sk_sid, sel_sid, SECCLASS_ASSOCIATION,
- ((dir == FLOW_DIR_IN) ? ASSOCIATION__RECVFROM :
- ((dir == FLOW_DIR_OUT) ? ASSOCIATION__SENDTO :
- (ASSOCIATION__SENDTO | ASSOCIATION__RECVFROM))),
+ rc = avc_has_perm(fl_secid, sel_sid, SECCLASS_ASSOCIATION,
+ ASSOCIATION__POLMATCH,
NULL);
+ if (rc == -EACCES)
+ rc = -ESRCH;
+
return rc;
}
+/*
+ * LSM hook implementation that authorizes that a state matches
+ * the given policy, flow combo.
+ */
+
+int selinux_xfrm_state_pol_flow_match(struct xfrm_state *x, struct xfrm_policy *xp,
+ struct flowi *fl)
+{
+ u32 state_sid;
+ int rc;
+
+ if (!xp->security)
+ if (x->security)
+ /* unlabeled policy and labeled SA can't match */
+ return 0;
+ else
+ /* unlabeled policy and unlabeled SA match all flows */
+ return 1;
+ else
+ if (!x->security)
+ /* unlabeled SA and labeled policy can't match */
+ return 0;
+ else
+ if (!selinux_authorizable_xfrm(x))
+ /* Not a SELinux-labeled SA */
+ return 0;
+
+ state_sid = x->security->ctx_sid;
+
+ if (fl->secid != state_sid)
+ return 0;
+
+ rc = avc_has_perm(fl->secid, state_sid, SECCLASS_ASSOCIATION,
+ ASSOCIATION__SENDTO,
+ NULL)? 0:1;
+
+ /*
+ * We don't need a separate SA Vs. policy polmatch check
+ * since the SA is now of the same label as the flow and
+ * a flow Vs. policy polmatch check had already happened
+ * in selinux_xfrm_policy_lookup() above.
+ */
+
+ return rc;
+}
+
+/*
+ * LSM hook implementation that checks and/or returns the xfrm sid for the
+ * incoming packet.
+ */
+
+int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall)
+{
+ struct sec_path *sp;
+
+ *sid = SECSID_NULL;
+
+ if (skb == NULL)
+ return 0;
+
+ sp = skb->sp;
+ if (sp) {
+ int i, sid_set = 0;
+
+ for (i = sp->len-1; i >= 0; i--) {
+ struct xfrm_state *x = sp->xvec[i];
+ if (selinux_authorizable_xfrm(x)) {
+ struct xfrm_sec_ctx *ctx = x->security;
+
+ if (!sid_set) {
+ *sid = ctx->ctx_sid;
+ sid_set = 1;
+
+ if (!ckall)
+ break;
+ }
+ else if (*sid != ctx->ctx_sid)
+ return -EINVAL;
+ }
+ }
+ }
+
+ return 0;
+}
+
/*
* Security blob allocation for xfrm_policy and xfrm_state
* CTX does not have a meaningful value on input
*/
-static int selinux_xfrm_sec_ctx_alloc(struct xfrm_sec_ctx **ctxp, struct xfrm_user_sec_ctx *uctx)
+static int selinux_xfrm_sec_ctx_alloc(struct xfrm_sec_ctx **ctxp,
+ struct xfrm_user_sec_ctx *uctx, u32 sid)
{
int rc = 0;
struct task_security_struct *tsec = current->security;
- struct xfrm_sec_ctx *ctx;
+ struct xfrm_sec_ctx *ctx = NULL;
+ char *ctx_str = NULL;
+ u32 str_len;
- BUG_ON(!uctx);
- BUG_ON(uctx->ctx_doi != XFRM_SC_ALG_SELINUX);
+ BUG_ON(uctx && sid);
+
+ if (!uctx)
+ goto not_from_user;
+
+ if (uctx->ctx_doi != XFRM_SC_ALG_SELINUX)
+ return -EINVAL;
if (uctx->ctx_len >= PAGE_SIZE)
return -ENOMEM;
return rc;
+not_from_user:
+ rc = security_sid_to_context(sid, &ctx_str, &str_len);
+ if (rc)
+ goto out;
+
+ *ctxp = ctx = kmalloc(sizeof(*ctx) +
+ str_len,
+ GFP_ATOMIC);
+
+ if (!ctx) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ ctx->ctx_doi = XFRM_SC_DOI_LSM;
+ ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
+ ctx->ctx_sid = sid;
+ ctx->ctx_len = str_len;
+ memcpy(ctx->ctx_str,
+ ctx_str,
+ str_len);
+
+ goto out2;
+
out:
*ctxp = NULL;
kfree(ctx);
+out2:
+ kfree(ctx_str);
return rc;
}
* LSM hook implementation that allocs and transfers uctx spec to
* xfrm_policy.
*/
-int selinux_xfrm_policy_alloc(struct xfrm_policy *xp, struct xfrm_user_sec_ctx *uctx)
+int selinux_xfrm_policy_alloc(struct xfrm_policy *xp,
+ struct xfrm_user_sec_ctx *uctx)
{
int err;
BUG_ON(!xp);
+ BUG_ON(!uctx);
- err = selinux_xfrm_sec_ctx_alloc(&xp->security, uctx);
+ err = selinux_xfrm_sec_ctx_alloc(&xp->security, uctx, 0);
return err;
}
* LSM hook implementation that allocs and transfers sec_ctx spec to
* xfrm_state.
*/
-int selinux_xfrm_state_alloc(struct xfrm_state *x, struct xfrm_user_sec_ctx *uctx)
+int selinux_xfrm_state_alloc(struct xfrm_state *x, struct xfrm_user_sec_ctx *uctx,
+ u32 secid)
{
int err;
BUG_ON(!x);
- err = selinux_xfrm_sec_ctx_alloc(&x->security, uctx);
+ err = selinux_xfrm_sec_ctx_alloc(&x->security, uctx, secid);
return err;
}
kfree(ctx);
}
-/*
- * SELinux internal function to retrieve the context of a connected
- * (sk->sk_state == TCP_ESTABLISHED) TCP socket based on its security
- * association used to connect to the remote socket.
- *
- * Retrieve via getsockopt SO_PEERSEC.
- */
-u32 selinux_socket_getpeer_stream(struct sock *sk)
-{
- struct dst_entry *dst, *dst_test;
- u32 peer_sid = SECSID_NULL;
-
- if (sk->sk_state != TCP_ESTABLISHED)
- goto out;
-
- dst = sk_dst_get(sk);
- if (!dst)
- goto out;
-
- for (dst_test = dst; dst_test != 0;
- dst_test = dst_test->child) {
- struct xfrm_state *x = dst_test->xfrm;
-
- if (x && selinux_authorizable_xfrm(x)) {
- struct xfrm_sec_ctx *ctx = x->security;
- peer_sid = ctx->ctx_sid;
- break;
- }
- }
- dst_release(dst);
-
-out:
- return peer_sid;
-}
-
-/*
- * SELinux internal function to retrieve the context of a UDP packet
- * based on its security association used to connect to the remote socket.
- *
- * Retrieve via setsockopt IP_PASSSEC and recvmsg with control message
- * type SCM_SECURITY.
- */
-u32 selinux_socket_getpeer_dgram(struct sk_buff *skb)
-{
- struct sec_path *sp;
-
- if (skb == NULL)
- return SECSID_NULL;
-
- if (skb->sk->sk_protocol != IPPROTO_UDP)
- return SECSID_NULL;
-
- sp = skb->sp;
- if (sp) {
- int i;
-
- for (i = sp->len-1; i >= 0; i--) {
- struct xfrm_state *x = sp->xvec[i];
- if (selinux_authorizable_xfrm(x)) {
- struct xfrm_sec_ctx *ctx = x->security;
- return ctx->ctx_sid;
- }
- }
- }
-
- return SECSID_NULL;
-}
-
/*
* LSM hook implementation that authorizes deletion of labeled SAs.
*/
* we need to check for unlabelled access since this may not have
* gone thru the IPSec process.
*/
-int selinux_xfrm_sock_rcv_skb(u32 isec_sid, struct sk_buff *skb)
+int selinux_xfrm_sock_rcv_skb(u32 isec_sid, struct sk_buff *skb,
+ struct avc_audit_data *ad)
{
int i, rc = 0;
struct sec_path *sp;
+ u32 sel_sid = SECINITSID_UNLABELED;
sp = skb->sp;
if (sp) {
- /*
- * __xfrm_policy_check does not approve unless xfrm_policy_ok
- * says that spi's match for policy and the socket.
- *
- * Only need to verify the existence of an authorizable sp.
- */
for (i = 0; i < sp->len; i++) {
struct xfrm_state *x = sp->xvec[i];
- if (x && selinux_authorizable_xfrm(x))
- goto accept;
+ if (x && selinux_authorizable_xfrm(x)) {
+ struct xfrm_sec_ctx *ctx = x->security;
+ sel_sid = ctx->ctx_sid;
+ break;
+ }
}
}
- /* check SELinux sock for unlabelled access */
- rc = avc_has_perm(isec_sid, SECINITSID_UNLABELED, SECCLASS_ASSOCIATION,
- ASSOCIATION__RECVFROM, NULL);
- if (rc)
- goto drop;
+ /*
+ * This check even when there's no association involved is
+ * intended, according to Trent Jaeger, to make sure a
+ * process can't engage in non-ipsec communication unless
+ * explicitly allowed by policy.
+ */
-accept:
- return 0;
+ rc = avc_has_perm(isec_sid, sel_sid, SECCLASS_ASSOCIATION,
+ ASSOCIATION__RECVFROM, ad);
-drop:
return rc;
}
* If we have no security association, then we need to determine
* whether the socket is allowed to send to an unlabelled destination.
* If we do have a authorizable security association, then it has already been
- * checked in xfrm_policy_lookup hook.
+ * checked in the selinux_xfrm_state_pol_flow_match hook above.
*/
-int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb)
+int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb,
+ struct avc_audit_data *ad, u8 proto)
{
struct dst_entry *dst;
int rc = 0;
}
}
+ switch (proto) {
+ case IPPROTO_AH:
+ case IPPROTO_ESP:
+ case IPPROTO_COMP:
+ /*
+ * We should have already seen this packet once before
+ * it underwent xfrm(s). No need to subject it to the
+ * unlabeled check.
+ */
+ goto out;
+ default:
+ break;
+ }
+
+ /*
+ * This check even when there's no association involved is
+ * intended, according to Trent Jaeger, to make sure a
+ * process can't engage in non-ipsec communication unless
+ * explicitly allowed by policy.
+ */
+
rc = avc_has_perm(isec_sid, SECINITSID_UNLABELED, SECCLASS_ASSOCIATION,
- ASSOCIATION__SENDTO, NULL);
+ ASSOCIATION__SENDTO, ad);
out:
return rc;
}
git.samba.org / sfrench / cifs-2.6.git / blobdiff