[linux-2.6-block.git] / security / selinux / xfrm.c

/*
 *  NSA Security-Enhanced Linux (SELinux) security module
 *
 *  This file contains the SELinux XFRM hook function implementations.
 *
 *  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,
 *	as published by the Free Software Foundation.
 */

/*
 * USAGE:
 * NOTES:
 *   1. Make sure to enable the following options in your kernel config:
 *	CONFIG_SECURITY=y
 *	CONFIG_SECURITY_NETWORK=y
 *	CONFIG_SECURITY_NETWORK_XFRM=y
 *	CONFIG_SECURITY_SELINUX=m/y
 * ISSUES:
 *   1. Caching packets, so they are not dropped during negotiation
 *   2. Emulating a reasonable SO_PEERSEC across machines
 *   3. Testing addition of sk_policy's with security context via setsockopt
 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/security.h>
#include <linux/types.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/skbuff.h>
#include <linux/xfrm.h>
#include <net/xfrm.h>
#include <net/checksum.h>
#include <net/udp.h>
#include <asm/semaphore.h>
#include <asm/atomic.h>

#include "avc.h"
#include "objsec.h"
#include "xfrm.h"

/* Labeled XFRM instance counter */
atomic_t selinux_xfrm_refcount = ATOMIC_INIT(0);

/*
 * Returns true if an LSM/SELinux context
 */
static inline int selinux_authorizable_ctx(struct xfrm_sec_ctx *ctx)
{
	return (ctx &&
		(ctx->ctx_doi == XFRM_SC_DOI_LSM) &&
		(ctx->ctx_alg == XFRM_SC_ALG_SELINUX));
}

/*
 * Returns true if the xfrm contains a security blob for SELinux
 */
static inline int selinux_authorizable_xfrm(struct xfrm_state *x)
{
	return selinux_authorizable_ctx(x->security);
}

/*
 * LSM hook implementation that authorizes that a flow can use
 * a xfrm policy rule.
 */
int selinux_xfrm_policy_lookup(struct xfrm_policy *xp, u32 fl_secid, u8 dir)
{
	int rc;
	u32 sel_sid;
	struct xfrm_sec_ctx *ctx;

	/* Context sid is either set to label or ANY_ASSOC */
	if ((ctx = xp->security)) {
		if (!selinux_authorizable_ctx(ctx))
			return -EINVAL;

		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(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, u32 sid)
{
	int rc = 0;
	struct task_security_struct *tsec = current->security;
	struct xfrm_sec_ctx *ctx = NULL;
	char *ctx_str = NULL;
	u32 str_len;

	BUG_ON(uctx && sid);

	if (!uctx)
		goto not_from_user;

	if (uctx->ctx_doi != XFRM_SC_ALG_SELINUX)
		return -EINVAL;

	str_len = uctx->ctx_len;
	if (str_len >= PAGE_SIZE)
		return -ENOMEM;

	*ctxp = ctx = kmalloc(sizeof(*ctx) +
			      str_len + 1,
			      GFP_KERNEL);

	if (!ctx)
		return -ENOMEM;

	ctx->ctx_doi = uctx->ctx_doi;
	ctx->ctx_len = str_len;
	ctx->ctx_alg = uctx->ctx_alg;

	memcpy(ctx->ctx_str,
	       uctx+1,
	       str_len);
	ctx->ctx_str[str_len] = 0;
	rc = security_context_to_sid(ctx->ctx_str,
				     str_len,
				     &ctx->ctx_sid);

	if (rc)
		goto out;

	/*
	 * Does the subject have permission to set security context?
	 */
	rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
			  SECCLASS_ASSOCIATION,
			  ASSOCIATION__SETCONTEXT, NULL);
	if (rc)
		goto out;

	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 err;

	BUG_ON(!xp);
	BUG_ON(!uctx);

	err = selinux_xfrm_sec_ctx_alloc(&xp->security, uctx, 0);
	if (err == 0)
		atomic_inc(&selinux_xfrm_refcount);

	return err;
}


/*
 * LSM hook implementation that copies security data structure from old to
 * new for policy cloning.
 */
int selinux_xfrm_policy_clone(struct xfrm_policy *old, struct xfrm_policy *new)
{
	struct xfrm_sec_ctx *old_ctx, *new_ctx;

	old_ctx = old->security;

	if (old_ctx) {
		new_ctx = new->security = kmalloc(sizeof(*new_ctx) +
						  old_ctx->ctx_len,
						  GFP_KERNEL);

		if (!new_ctx)
			return -ENOMEM;

		memcpy(new_ctx, old_ctx, sizeof(*new_ctx));
		memcpy(new_ctx->ctx_str, old_ctx->ctx_str, new_ctx->ctx_len);
	}
	return 0;
}

/*
 * LSM hook implementation that frees xfrm_policy security information.
 */
void selinux_xfrm_policy_free(struct xfrm_policy *xp)
{
	struct xfrm_sec_ctx *ctx = xp->security;
	if (ctx)
		kfree(ctx);
}

/*
 * LSM hook implementation that authorizes deletion of labeled policies.
 */
int selinux_xfrm_policy_delete(struct xfrm_policy *xp)
{
	struct task_security_struct *tsec = current->security;
	struct xfrm_sec_ctx *ctx = xp->security;
	int rc = 0;

	if (ctx) {
		rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
				  SECCLASS_ASSOCIATION,
				  ASSOCIATION__SETCONTEXT, NULL);
		if (rc == 0)
			atomic_dec(&selinux_xfrm_refcount);
	}

	return rc;
}

/*
 * 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,
		u32 secid)
{
	int err;

	BUG_ON(!x);

	err = selinux_xfrm_sec_ctx_alloc(&x->security, uctx, secid);
	if (err == 0)
		atomic_inc(&selinux_xfrm_refcount);
	return err;
}

/*
 * LSM hook implementation that frees xfrm_state security information.
 */
void selinux_xfrm_state_free(struct xfrm_state *x)
{
	struct xfrm_sec_ctx *ctx = x->security;
	if (ctx)
		kfree(ctx);
}

 /*
  * LSM hook implementation that authorizes deletion of labeled SAs.
  */
int selinux_xfrm_state_delete(struct xfrm_state *x)
{
	struct task_security_struct *tsec = current->security;
	struct xfrm_sec_ctx *ctx = x->security;
	int rc = 0;

	if (ctx) {
		rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
				  SECCLASS_ASSOCIATION,
				  ASSOCIATION__SETCONTEXT, NULL);
		if (rc == 0)
			atomic_dec(&selinux_xfrm_refcount);
	}

	return rc;
}

/*
 * LSM hook that controls access to unlabelled packets.  If
 * a xfrm_state is authorizable (defined by macro) then it was
 * already authorized by the IPSec process.  If not, then
 * 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,
				struct avc_audit_data *ad)
{
	int i, rc = 0;
	struct sec_path *sp;
	u32 sel_sid = SECINITSID_UNLABELED;

	sp = skb->sp;

	if (sp) {
		for (i = 0; i < sp->len; i++) {
			struct xfrm_state *x = sp->xvec[i];

			if (x && selinux_authorizable_xfrm(x)) {
				struct xfrm_sec_ctx *ctx = x->security;
				sel_sid = ctx->ctx_sid;
				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, sel_sid, SECCLASS_ASSOCIATION,
			  ASSOCIATION__RECVFROM, ad);

	return rc;
}

/*
 * POSTROUTE_LAST hook's XFRM processing:
 * 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 the selinux_xfrm_state_pol_flow_match hook above.
 */
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;

	dst = skb->dst;

	if (dst) {
		struct dst_entry *dst_test;

		for (dst_test = dst; dst_test != NULL;
		     dst_test = dst_test->child) {
			struct xfrm_state *x = dst_test->xfrm;

			if (x && selinux_authorizable_xfrm(x))
				goto out;
		}
	}

	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, ad);
out:
	return rc;
}
Commit	Line	Data
d28d1e08 TJ	1	/*
	2	* NSA Security-Enhanced Linux (SELinux) security module
	3	*
	4	* This file contains the SELinux XFRM hook function implementations.
	5	*
	6	* Authors: Serge Hallyn <sergeh@us.ibm.com>
	7	* Trent Jaeger <jaegert@us.ibm.com>
	8	*
e0d1caa7 VY	9	* Updated: Venkat Yekkirala <vyekkirala@TrustedCS.com>
	10	*
	11	* Granular IPSec Associations for use in MLS environments.
	12	*
d28d1e08	13	* Copyright (C) 2005 International Business Machines Corporation
e0d1caa7	14	* Copyright (C) 2006 Trusted Computer Solutions, Inc.
d28d1e08 TJ	15	*
	16	* This program is free software; you can redistribute it and/or modify
	17	* it under the terms of the GNU General Public License version 2,
	18	* as published by the Free Software Foundation.
	19	*/
	20
	21	/*
	22	* USAGE:
	23	* NOTES:
	24	* 1. Make sure to enable the following options in your kernel config:
	25	* CONFIG_SECURITY=y
	26	* CONFIG_SECURITY_NETWORK=y
	27	* CONFIG_SECURITY_NETWORK_XFRM=y
	28	* CONFIG_SECURITY_SELINUX=m/y
	29	* ISSUES:
	30	* 1. Caching packets, so they are not dropped during negotiation
	31	* 2. Emulating a reasonable SO_PEERSEC across machines
	32	* 3. Testing addition of sk_policy's with security context via setsockopt
	33	*/
d28d1e08 TJ	34	#include <linux/kernel.h>
	35	#include <linux/init.h>
	36	#include <linux/security.h>
	37	#include <linux/types.h>
	38	#include <linux/netfilter.h>
	39	#include <linux/netfilter_ipv4.h>
	40	#include <linux/netfilter_ipv6.h>
	41	#include <linux/ip.h>
	42	#include <linux/tcp.h>
	43	#include <linux/skbuff.h>
	44	#include <linux/xfrm.h>
	45	#include <net/xfrm.h>
	46	#include <net/checksum.h>
	47	#include <net/udp.h>
	48	#include <asm/semaphore.h>
d621d35e	49	#include <asm/atomic.h>
d28d1e08 TJ	50
	51	#include "avc.h"
	52	#include "objsec.h"
	53	#include "xfrm.h"
	54
d621d35e PM	55	/* Labeled XFRM instance counter */
d621d35e PM	56	atomic_t selinux_xfrm_refcount = ATOMIC_INIT(0);
d28d1e08 TJ	57
	58	/*
	59	* Returns true if an LSM/SELinux context
	60	*/
	61	static inline int selinux_authorizable_ctx(struct xfrm_sec_ctx *ctx)
	62	{
	63	return (ctx &&
	64	(ctx->ctx_doi == XFRM_SC_DOI_LSM) &&
	65	(ctx->ctx_alg == XFRM_SC_ALG_SELINUX));
	66	}
	67
	68	/*
	69	* Returns true if the xfrm contains a security blob for SELinux
	70	*/
	71	static inline int selinux_authorizable_xfrm(struct xfrm_state *x)
	72	{
	73	return selinux_authorizable_ctx(x->security);
	74	}
	75
	76	/*
e0d1caa7 VY	77	* LSM hook implementation that authorizes that a flow can use
e0d1caa7 VY	78	* a xfrm policy rule.
d28d1e08	79	*/
e0d1caa7	80	int selinux_xfrm_policy_lookup(struct xfrm_policy *xp, u32 fl_secid, u8 dir)
d28d1e08	81	{
5b368e61 VY	82	int rc;
5b368e61 VY	83	u32 sel_sid;
d28d1e08 TJ	84	struct xfrm_sec_ctx *ctx;
	85
	86	/* Context sid is either set to label or ANY_ASSOC */
	87	if ((ctx = xp->security)) {
	88	if (!selinux_authorizable_ctx(ctx))
	89	return -EINVAL;
	90
	91	sel_sid = ctx->ctx_sid;
	92	}
5b368e61 VY	93	else
	94	/*
	95	* All flows should be treated as polmatch'ing an
	96	* otherwise applicable "non-labeled" policy. This
	97	* would prevent inadvertent "leaks".
	98	*/
	99	return 0;
d28d1e08	100
e0d1caa7 VY	101	rc = avc_has_perm(fl_secid, sel_sid, SECCLASS_ASSOCIATION,
e0d1caa7 VY	102	ASSOCIATION__POLMATCH,
d28d1e08 TJ	103	NULL);
d28d1e08 TJ	104
5b368e61 VY	105	if (rc == -EACCES)
	106	rc = -ESRCH;
	107
d28d1e08 TJ	108	return rc;
	109	}
	110
e0d1caa7 VY	111	/*
	112	* LSM hook implementation that authorizes that a state matches
	113	* the given policy, flow combo.
	114	*/
	115
	116	int selinux_xfrm_state_pol_flow_match(struct xfrm_state x, struct xfrm_policy xp,
	117	struct flowi *fl)
	118	{
	119	u32 state_sid;
67f83cbf	120	int rc;
e0d1caa7	121
67f83cbf	122	if (!xp->security)
5b368e61 VY	123	if (x->security)
	124	/* unlabeled policy and labeled SA can't match */
	125	return 0;
	126	else
	127	/* unlabeled policy and unlabeled SA match all flows */
	128	return 1;
5b368e61	129	else
67f83cbf VY	130	if (!x->security)
67f83cbf VY	131	/* unlabeled SA and labeled policy can't match */
5b368e61	132	return 0;
67f83cbf VY	133	else
	134	if (!selinux_authorizable_xfrm(x))
	135	/* Not a SELinux-labeled SA */
	136	return 0;
5b368e61	137
67f83cbf	138	state_sid = x->security->ctx_sid;
e0d1caa7	139
67f83cbf VY	140	if (fl->secid != state_sid)
67f83cbf VY	141	return 0;
e0d1caa7	142
67f83cbf	143	rc = avc_has_perm(fl->secid, state_sid, SECCLASS_ASSOCIATION,
e0d1caa7 VY	144	ASSOCIATION__SENDTO,
	145	NULL)? 0:1;
	146
67f83cbf VY	147	/*
	148	* We don't need a separate SA Vs. policy polmatch check
	149	* since the SA is now of the same label as the flow and
	150	* a flow Vs. policy polmatch check had already happened
	151	* in selinux_xfrm_policy_lookup() above.
	152	*/
	153
e0d1caa7 VY	154	return rc;
	155	}
	156
	157	/*
6b877699 VY	158	* LSM hook implementation that checks and/or returns the xfrm sid for the
6b877699 VY	159	* incoming packet.
e0d1caa7 VY	160	*/
e0d1caa7 VY	161
beb8d13b	162	int selinux_xfrm_decode_session(struct sk_buff skb, u32 sid, int ckall)
e0d1caa7 VY	163	{
	164	struct sec_path *sp;
	165
beb8d13b	166	*sid = SECSID_NULL;
e0d1caa7 VY	167
	168	if (skb == NULL)
	169	return 0;
	170
	171	sp = skb->sp;
	172	if (sp) {
	173	int i, sid_set = 0;
	174
	175	for (i = sp->len-1; i >= 0; i--) {
	176	struct xfrm_state *x = sp->xvec[i];
	177	if (selinux_authorizable_xfrm(x)) {
	178	struct xfrm_sec_ctx *ctx = x->security;
	179
	180	if (!sid_set) {
beb8d13b	181	*sid = ctx->ctx_sid;
e0d1caa7	182	sid_set = 1;
beb8d13b VY	183
	184	if (!ckall)
	185	break;
e0d1caa7	186	}
beb8d13b	187	else if (*sid != ctx->ctx_sid)
e0d1caa7 VY	188	return -EINVAL;
	189	}
	190	}
	191	}
	192
	193	return 0;
	194	}
	195
d28d1e08 TJ	196	/*
	197	* Security blob allocation for xfrm_policy and xfrm_state
	198	* CTX does not have a meaningful value on input
	199	*/
e0d1caa7	200	static int selinux_xfrm_sec_ctx_alloc(struct xfrm_sec_ctx **ctxp,
c1a856c9	201	struct xfrm_user_sec_ctx *uctx, u32 sid)
d28d1e08 TJ	202	{
	203	int rc = 0;
	204	struct task_security_struct *tsec = current->security;
e0d1caa7 VY	205	struct xfrm_sec_ctx *ctx = NULL;
	206	char *ctx_str = NULL;
	207	u32 str_len;
e0d1caa7	208
c1a856c9	209	BUG_ON(uctx && sid);
e0d1caa7	210
cb969f07 VY	211	if (!uctx)
cb969f07 VY	212	goto not_from_user;
e0d1caa7 VY	213
	214	if (uctx->ctx_doi != XFRM_SC_ALG_SELINUX)
	215	return -EINVAL;
d28d1e08	216
57002bfb SR	217	str_len = uctx->ctx_len;
57002bfb SR	218	if (str_len >= PAGE_SIZE)
d28d1e08 TJ	219	return -ENOMEM;
	220
	221	ctxp = ctx = kmalloc(sizeof(ctx) +
57002bfb	222	str_len + 1,
d28d1e08 TJ	223	GFP_KERNEL);
	224
	225	if (!ctx)
	226	return -ENOMEM;
	227
	228	ctx->ctx_doi = uctx->ctx_doi;
57002bfb	229	ctx->ctx_len = str_len;
d28d1e08 TJ	230	ctx->ctx_alg = uctx->ctx_alg;
	231
	232	memcpy(ctx->ctx_str,
	233	uctx+1,
57002bfb SR	234	str_len);
57002bfb SR	235	ctx->ctx_str[str_len] = 0;
d28d1e08	236	rc = security_context_to_sid(ctx->ctx_str,
57002bfb	237	str_len,
d28d1e08 TJ	238	&ctx->ctx_sid);
	239
	240	if (rc)
	241	goto out;
	242
	243	/*
c8c05a8e	244	* Does the subject have permission to set security context?
d28d1e08	245	*/
d28d1e08 TJ	246	rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
d28d1e08 TJ	247	SECCLASS_ASSOCIATION,
5f8ac64b	248	ASSOCIATION__SETCONTEXT, NULL);
d28d1e08 TJ	249	if (rc)
	250	goto out;
	251
	252	return rc;
	253
cb969f07	254	not_from_user:
c1a856c9	255	rc = security_sid_to_context(sid, &ctx_str, &str_len);
e0d1caa7 VY	256	if (rc)
	257	goto out;
	258
	259	ctxp = ctx = kmalloc(sizeof(ctx) +
	260	str_len,
	261	GFP_ATOMIC);
	262
	263	if (!ctx) {
	264	rc = -ENOMEM;
	265	goto out;
	266	}
	267
e0d1caa7 VY	268	ctx->ctx_doi = XFRM_SC_DOI_LSM;
e0d1caa7 VY	269	ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
c1a856c9	270	ctx->ctx_sid = sid;
e0d1caa7 VY	271	ctx->ctx_len = str_len;
	272	memcpy(ctx->ctx_str,
	273	ctx_str,
	274	str_len);
	275
	276	goto out2;
	277
d28d1e08	278	out:
ee2e6841	279	*ctxp = NULL;
d28d1e08	280	kfree(ctx);
e0d1caa7 VY	281	out2:
e0d1caa7 VY	282	kfree(ctx_str);
d28d1e08 TJ	283	return rc;
	284	}
	285
	286	/*
	287	* LSM hook implementation that allocs and transfers uctx spec to
	288	* xfrm_policy.
	289	*/
cb969f07	290	int selinux_xfrm_policy_alloc(struct xfrm_policy *xp,
c1a856c9	291	struct xfrm_user_sec_ctx *uctx)
d28d1e08 TJ	292	{
	293	int err;
	294
	295	BUG_ON(!xp);
c1a856c9	296	BUG_ON(!uctx);
d28d1e08	297
c1a856c9	298	err = selinux_xfrm_sec_ctx_alloc(&xp->security, uctx, 0);
d621d35e PM	299	if (err == 0)
	300	atomic_inc(&selinux_xfrm_refcount);
	301
d28d1e08 TJ	302	return err;
	303	}
	304
	305
	306	/*
	307	* LSM hook implementation that copies security data structure from old to
	308	* new for policy cloning.
	309	*/
	310	int selinux_xfrm_policy_clone(struct xfrm_policy old, struct xfrm_policy new)
	311	{
	312	struct xfrm_sec_ctx old_ctx, new_ctx;
	313
	314	old_ctx = old->security;
	315
	316	if (old_ctx) {
	317	new_ctx = new->security = kmalloc(sizeof(*new_ctx) +
	318	old_ctx->ctx_len,
	319	GFP_KERNEL);
	320
	321	if (!new_ctx)
	322	return -ENOMEM;
	323
	324	memcpy(new_ctx, old_ctx, sizeof(*new_ctx));
	325	memcpy(new_ctx->ctx_str, old_ctx->ctx_str, new_ctx->ctx_len);
	326	}
	327	return 0;
	328	}
	329
	330	/*
	331	* LSM hook implementation that frees xfrm_policy security information.
	332	*/
	333	void selinux_xfrm_policy_free(struct xfrm_policy *xp)
	334	{
	335	struct xfrm_sec_ctx *ctx = xp->security;
	336	if (ctx)
	337	kfree(ctx);
	338	}
	339
c8c05a8e CZ	340	/*
	341	* LSM hook implementation that authorizes deletion of labeled policies.
	342	*/
	343	int selinux_xfrm_policy_delete(struct xfrm_policy *xp)
	344	{
	345	struct task_security_struct *tsec = current->security;
	346	struct xfrm_sec_ctx *ctx = xp->security;
	347	int rc = 0;
	348
d621d35e	349	if (ctx) {
c8c05a8e CZ	350	rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
	351	SECCLASS_ASSOCIATION,
	352	ASSOCIATION__SETCONTEXT, NULL);
d621d35e PM	353	if (rc == 0)
	354	atomic_dec(&selinux_xfrm_refcount);
	355	}
c8c05a8e CZ	356
	357	return rc;
	358	}
	359
d28d1e08 TJ	360	/*
	361	* LSM hook implementation that allocs and transfers sec_ctx spec to
	362	* xfrm_state.
	363	*/
e0d1caa7	364	int selinux_xfrm_state_alloc(struct xfrm_state x, struct xfrm_user_sec_ctx uctx,
c1a856c9	365	u32 secid)
d28d1e08 TJ	366	{
	367	int err;
	368
	369	BUG_ON(!x);
	370
c1a856c9	371	err = selinux_xfrm_sec_ctx_alloc(&x->security, uctx, secid);
d621d35e PM	372	if (err == 0)
d621d35e PM	373	atomic_inc(&selinux_xfrm_refcount);
d28d1e08 TJ	374	return err;
	375	}
	376
	377	/*
	378	* LSM hook implementation that frees xfrm_state security information.
	379	*/
	380	void selinux_xfrm_state_free(struct xfrm_state *x)
	381	{
	382	struct xfrm_sec_ctx *ctx = x->security;
	383	if (ctx)
	384	kfree(ctx);
	385	}
	386
c8c05a8e CZ	387	/*
	388	* LSM hook implementation that authorizes deletion of labeled SAs.
	389	*/
	390	int selinux_xfrm_state_delete(struct xfrm_state *x)
	391	{
	392	struct task_security_struct *tsec = current->security;
	393	struct xfrm_sec_ctx *ctx = x->security;
	394	int rc = 0;
	395
d621d35e	396	if (ctx) {
c8c05a8e CZ	397	rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
	398	SECCLASS_ASSOCIATION,
	399	ASSOCIATION__SETCONTEXT, NULL);
d621d35e PM	400	if (rc == 0)
	401	atomic_dec(&selinux_xfrm_refcount);
	402	}
c8c05a8e CZ	403
	404	return rc;
	405	}
	406
d28d1e08 TJ	407	/*
	408	* LSM hook that controls access to unlabelled packets. If
	409	* a xfrm_state is authorizable (defined by macro) then it was
	410	* already authorized by the IPSec process. If not, then
	411	* we need to check for unlabelled access since this may not have
	412	* gone thru the IPSec process.
	413	*/
e0d1caa7 VY	414	int selinux_xfrm_sock_rcv_skb(u32 isec_sid, struct sk_buff *skb,
e0d1caa7 VY	415	struct avc_audit_data *ad)
d28d1e08 TJ	416	{
	417	int i, rc = 0;
	418	struct sec_path *sp;
e0d1caa7	419	u32 sel_sid = SECINITSID_UNLABELED;
d28d1e08 TJ	420
	421	sp = skb->sp;
	422
	423	if (sp) {
d28d1e08	424	for (i = 0; i < sp->len; i++) {
67644726	425	struct xfrm_state *x = sp->xvec[i];
d28d1e08	426
e0d1caa7 VY	427	if (x && selinux_authorizable_xfrm(x)) {
	428	struct xfrm_sec_ctx *ctx = x->security;
	429	sel_sid = ctx->ctx_sid;
	430	break;
	431	}
d28d1e08 TJ	432	}
	433	}
	434
67f83cbf VY	435	/*
	436	* This check even when there's no association involved is
	437	* intended, according to Trent Jaeger, to make sure a
	438	* process can't engage in non-ipsec communication unless
	439	* explicitly allowed by policy.
	440	*/
	441
e0d1caa7 VY	442	rc = avc_has_perm(isec_sid, sel_sid, SECCLASS_ASSOCIATION,
e0d1caa7 VY	443	ASSOCIATION__RECVFROM, ad);
d28d1e08	444
d28d1e08 TJ	445	return rc;
	446	}
	447
	448	/*
	449	* POSTROUTE_LAST hook's XFRM processing:
	450	* If we have no security association, then we need to determine
	451	* whether the socket is allowed to send to an unlabelled destination.
	452	* If we do have a authorizable security association, then it has already been
67f83cbf	453	* checked in the selinux_xfrm_state_pol_flow_match hook above.
d28d1e08	454	*/
e0d1caa7	455	int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb,
67f83cbf	456	struct avc_audit_data *ad, u8 proto)
d28d1e08 TJ	457	{
	458	struct dst_entry *dst;
	459	int rc = 0;
	460
	461	dst = skb->dst;
	462
	463	if (dst) {
	464	struct dst_entry *dst_test;
	465
c80544dc	466	for (dst_test = dst; dst_test != NULL;
d28d1e08 TJ	467	dst_test = dst_test->child) {
	468	struct xfrm_state *x = dst_test->xfrm;
	469
	470	if (x && selinux_authorizable_xfrm(x))
4e5ab4cb	471	goto out;
d28d1e08 TJ	472	}
	473	}
	474
67f83cbf VY	475	switch (proto) {
	476	case IPPROTO_AH:
	477	case IPPROTO_ESP:
	478	case IPPROTO_COMP:
	479	/*
	480	* We should have already seen this packet once before
	481	* it underwent xfrm(s). No need to subject it to the
	482	* unlabeled check.
	483	*/
	484	goto out;
	485	default:
	486	break;
	487	}
	488
	489	/*
	490	* This check even when there's no association involved is
	491	* intended, according to Trent Jaeger, to make sure a
	492	* process can't engage in non-ipsec communication unless
	493	* explicitly allowed by policy.
	494	*/
	495
d28d1e08	496	rc = avc_has_perm(isec_sid, SECINITSID_UNLABELED, SECCLASS_ASSOCIATION,
e0d1caa7	497	ASSOCIATION__SENDTO, ad);
4e5ab4cb JM	498	out:
4e5ab4cb JM	499	return rc;
d28d1e08	500	}