[mirror_ubuntu-bionic-kernel.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/module.h>
#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 "avc.h"
#include "objsec.h"
#include "xfrm.h"


/*
 * 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 = 0;
	u32 sel_sid = SECINITSID_UNLABELED;
	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;
	}

	rc = avc_has_perm(fl_secid, sel_sid, SECCLASS_ASSOCIATION,
			  ASSOCIATION__POLMATCH,
			  NULL);

	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;
	u32 pol_sid;
	int err;

	if (x->security)
		state_sid = x->security->ctx_sid;
	else
		state_sid = SECINITSID_UNLABELED;

	if (xp->security)
		pol_sid = xp->security->ctx_sid;
	else
		pol_sid = SECINITSID_UNLABELED;

	err = avc_has_perm(state_sid, pol_sid, SECCLASS_ASSOCIATION,
			  ASSOCIATION__POLMATCH,
			  NULL);

	if (err)
		return 0;

	return selinux_xfrm_flow_state_match(fl, x);
}

/*
 * LSM hook implementation that authorizes that a particular outgoing flow
 * can use a given security association.
 */

int selinux_xfrm_flow_state_match(struct flowi *fl, struct xfrm_state *xfrm)
{
	int rc = 0;
	u32 sel_sid = SECINITSID_UNLABELED;
	struct xfrm_sec_ctx *ctx;

	/* Context sid is either set to label or ANY_ASSOC */
	if ((ctx = xfrm->security)) {
		if (!selinux_authorizable_ctx(ctx))
			return 0;

		sel_sid = ctx->ctx_sid;
	}

	rc = avc_has_perm(fl->secid, sel_sid, SECCLASS_ASSOCIATION,
			  ASSOCIATION__SENDTO,
			  NULL)? 0:1;

	return rc;
}

/*
 * LSM hook implementation that determines the sid for the session.
 */

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, struct xfrm_sec_ctx *pol, 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;
	u32 ctx_sid;

	BUG_ON(uctx && pol);

	if (!uctx)
		goto not_from_user;

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

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

	*ctxp = ctx = kmalloc(sizeof(*ctx) +
			      uctx->ctx_len,
			      GFP_KERNEL);

	if (!ctx)
		return -ENOMEM;

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

	memcpy(ctx->ctx_str,
	       uctx+1,
	       ctx->ctx_len);
	rc = security_context_to_sid(ctx->ctx_str,
				     ctx->ctx_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:
	if (pol) {
		rc = security_sid_mls_copy(pol->ctx_sid, sid, &ctx_sid);
		if (rc)
			goto out;
	}
	else
		ctx_sid = sid;

	rc = security_sid_to_context(ctx_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 = ctx_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, struct sock *sk)
{
	int err;
	u32 sid;

	BUG_ON(!xp);
	BUG_ON(uctx && sk);

	if (sk) {
		struct sk_security_struct *ssec = sk->sk_security;
		sid = ssec->sid;
	}
	else
		sid = SECSID_NULL;

	err = selinux_xfrm_sec_ctx_alloc(&xp->security, uctx, NULL, sid);
	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);

	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,
		struct xfrm_sec_ctx *pol, u32 secid)
{
	int err;

	BUG_ON(!x);

	err = selinux_xfrm_sec_ctx_alloc(&x->security, uctx, pol, secid);
	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);
}

/*
 * 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.
  */
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);

	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;
			}
		}
	}

	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 xfrm_policy_lookup hook.
 */
int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb,
					struct avc_audit_data *ad)
{
	struct dst_entry *dst;
	int rc = 0;

	dst = skb->dst;

	if (dst) {
		struct dst_entry *dst_test;

		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))
				goto out;
		}
	}

	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/module.h>
	35	#include <linux/kernel.h>
	36	#include <linux/init.h>
	37	#include <linux/security.h>
	38	#include <linux/types.h>
	39	#include <linux/netfilter.h>
	40	#include <linux/netfilter_ipv4.h>
	41	#include <linux/netfilter_ipv6.h>
	42	#include <linux/ip.h>
	43	#include <linux/tcp.h>
	44	#include <linux/skbuff.h>
	45	#include <linux/xfrm.h>
	46	#include <net/xfrm.h>
	47	#include <net/checksum.h>
	48	#include <net/udp.h>
	49	#include <asm/semaphore.h>
	50
	51	#include "avc.h"
	52	#include "objsec.h"
	53	#include "xfrm.h"
	54
	55
	56	/*
	57	* Returns true if an LSM/SELinux context
	58	*/
	59	static inline int selinux_authorizable_ctx(struct xfrm_sec_ctx *ctx)
	60	{
	61	return (ctx &&
	62	(ctx->ctx_doi == XFRM_SC_DOI_LSM) &&
	63	(ctx->ctx_alg == XFRM_SC_ALG_SELINUX));
	64	}
	65
	66	/*
	67	* Returns true if the xfrm contains a security blob for SELinux
	68	*/
	69	static inline int selinux_authorizable_xfrm(struct xfrm_state *x)
	70	{
	71	return selinux_authorizable_ctx(x->security);
	72	}
	73
	74	/*
e0d1caa7 VY	75	* LSM hook implementation that authorizes that a flow can use
e0d1caa7 VY	76	* a xfrm policy rule.
d28d1e08	77	*/
e0d1caa7	78	int selinux_xfrm_policy_lookup(struct xfrm_policy *xp, u32 fl_secid, u8 dir)
d28d1e08 TJ	79	{
	80	int rc = 0;
	81	u32 sel_sid = SECINITSID_UNLABELED;
	82	struct xfrm_sec_ctx *ctx;
	83
	84	/* Context sid is either set to label or ANY_ASSOC */
	85	if ((ctx = xp->security)) {
	86	if (!selinux_authorizable_ctx(ctx))
	87	return -EINVAL;
	88
	89	sel_sid = ctx->ctx_sid;
	90	}
	91
e0d1caa7 VY	92	rc = avc_has_perm(fl_secid, sel_sid, SECCLASS_ASSOCIATION,
e0d1caa7 VY	93	ASSOCIATION__POLMATCH,
d28d1e08 TJ	94	NULL);
	95
	96	return rc;
	97	}
	98
e0d1caa7 VY	99	/*
	100	* LSM hook implementation that authorizes that a state matches
	101	* the given policy, flow combo.
	102	*/
	103
	104	int selinux_xfrm_state_pol_flow_match(struct xfrm_state x, struct xfrm_policy xp,
	105	struct flowi *fl)
	106	{
	107	u32 state_sid;
	108	u32 pol_sid;
	109	int err;
	110
	111	if (x->security)
	112	state_sid = x->security->ctx_sid;
	113	else
	114	state_sid = SECINITSID_UNLABELED;
	115
	116	if (xp->security)
	117	pol_sid = xp->security->ctx_sid;
	118	else
	119	pol_sid = SECINITSID_UNLABELED;
	120
	121	err = avc_has_perm(state_sid, pol_sid, SECCLASS_ASSOCIATION,
	122	ASSOCIATION__POLMATCH,
	123	NULL);
	124
	125	if (err)
	126	return 0;
	127
	128	return selinux_xfrm_flow_state_match(fl, x);
	129	}
	130
	131	/*
	132	* LSM hook implementation that authorizes that a particular outgoing flow
	133	* can use a given security association.
	134	*/
	135
	136	int selinux_xfrm_flow_state_match(struct flowi fl, struct xfrm_state xfrm)
	137	{
	138	int rc = 0;
	139	u32 sel_sid = SECINITSID_UNLABELED;
	140	struct xfrm_sec_ctx *ctx;
	141
	142	/* Context sid is either set to label or ANY_ASSOC */
	143	if ((ctx = xfrm->security)) {
	144	if (!selinux_authorizable_ctx(ctx))
	145	return 0;
	146
	147	sel_sid = ctx->ctx_sid;
	148	}
	149
	150	rc = avc_has_perm(fl->secid, sel_sid, SECCLASS_ASSOCIATION,
	151	ASSOCIATION__SENDTO,
	152	NULL)? 0:1;
	153
	154	return rc;
	155	}
	156
	157	/*
	158	* LSM hook implementation that determines the sid for the session.
	159	*/
	160
beb8d13b	161	int selinux_xfrm_decode_session(struct sk_buff skb, u32 sid, int ckall)
e0d1caa7 VY	162	{
	163	struct sec_path *sp;
	164
beb8d13b	165	*sid = SECSID_NULL;
e0d1caa7 VY	166
	167	if (skb == NULL)
	168	return 0;
	169
	170	sp = skb->sp;
	171	if (sp) {
	172	int i, sid_set = 0;
	173
	174	for (i = sp->len-1; i >= 0; i--) {
	175	struct xfrm_state *x = sp->xvec[i];
	176	if (selinux_authorizable_xfrm(x)) {
	177	struct xfrm_sec_ctx *ctx = x->security;
	178
	179	if (!sid_set) {
beb8d13b	180	*sid = ctx->ctx_sid;
e0d1caa7	181	sid_set = 1;
beb8d13b VY	182
	183	if (!ckall)
	184	break;
e0d1caa7	185	}
beb8d13b	186	else if (*sid != ctx->ctx_sid)
e0d1caa7 VY	187	return -EINVAL;
	188	}
	189	}
	190	}
	191
	192	return 0;
	193	}
	194
d28d1e08 TJ	195	/*
	196	* Security blob allocation for xfrm_policy and xfrm_state
	197	* CTX does not have a meaningful value on input
	198	*/
e0d1caa7 VY	199	static int selinux_xfrm_sec_ctx_alloc(struct xfrm_sec_ctx **ctxp,
e0d1caa7 VY	200	struct xfrm_user_sec_ctx uctx, struct xfrm_sec_ctx pol, u32 sid)
d28d1e08 TJ	201	{
	202	int rc = 0;
	203	struct task_security_struct *tsec = current->security;
e0d1caa7 VY	204	struct xfrm_sec_ctx *ctx = NULL;
	205	char *ctx_str = NULL;
	206	u32 str_len;
	207	u32 ctx_sid;
	208
	209	BUG_ON(uctx && pol);
	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 TJ	216
	217	if (uctx->ctx_len >= PAGE_SIZE)
	218	return -ENOMEM;
	219
	220	ctxp = ctx = kmalloc(sizeof(ctx) +
	221	uctx->ctx_len,
	222	GFP_KERNEL);
	223
	224	if (!ctx)
	225	return -ENOMEM;
	226
	227	ctx->ctx_doi = uctx->ctx_doi;
	228	ctx->ctx_len = uctx->ctx_len;
	229	ctx->ctx_alg = uctx->ctx_alg;
	230
	231	memcpy(ctx->ctx_str,
	232	uctx+1,
	233	ctx->ctx_len);
	234	rc = security_context_to_sid(ctx->ctx_str,
	235	ctx->ctx_len,
	236	&ctx->ctx_sid);
	237
	238	if (rc)
	239	goto out;
	240
	241	/*
c8c05a8e	242	* Does the subject have permission to set security context?
d28d1e08	243	*/
d28d1e08 TJ	244	rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
d28d1e08 TJ	245	SECCLASS_ASSOCIATION,
5f8ac64b	246	ASSOCIATION__SETCONTEXT, NULL);
d28d1e08 TJ	247	if (rc)
	248	goto out;
	249
	250	return rc;
	251
cb969f07 VY	252	not_from_user:
	253	if (pol) {
	254	rc = security_sid_mls_copy(pol->ctx_sid, sid, &ctx_sid);
	255	if (rc)
	256	goto out;
	257	}
	258	else
	259	ctx_sid = sid;
e0d1caa7 VY	260
	261	rc = security_sid_to_context(ctx_sid, &ctx_str, &str_len);
	262	if (rc)
	263	goto out;
	264
	265	ctxp = ctx = kmalloc(sizeof(ctx) +
	266	str_len,
	267	GFP_ATOMIC);
	268
	269	if (!ctx) {
	270	rc = -ENOMEM;
	271	goto out;
	272	}
	273
e0d1caa7 VY	274	ctx->ctx_doi = XFRM_SC_DOI_LSM;
	275	ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
	276	ctx->ctx_sid = ctx_sid;
	277	ctx->ctx_len = str_len;
	278	memcpy(ctx->ctx_str,
	279	ctx_str,
	280	str_len);
	281
	282	goto out2;
	283
d28d1e08	284	out:
ee2e6841	285	*ctxp = NULL;
d28d1e08	286	kfree(ctx);
e0d1caa7 VY	287	out2:
e0d1caa7 VY	288	kfree(ctx_str);
d28d1e08 TJ	289	return rc;
	290	}
	291
	292	/*
	293	* LSM hook implementation that allocs and transfers uctx spec to
	294	* xfrm_policy.
	295	*/
cb969f07 VY	296	int selinux_xfrm_policy_alloc(struct xfrm_policy *xp,
cb969f07 VY	297	struct xfrm_user_sec_ctx uctx, struct sock sk)
d28d1e08 TJ	298	{
d28d1e08 TJ	299	int err;
cb969f07	300	u32 sid;
d28d1e08 TJ	301
d28d1e08 TJ	302	BUG_ON(!xp);
cb969f07 VY	303	BUG_ON(uctx && sk);
	304
	305	if (sk) {
	306	struct sk_security_struct *ssec = sk->sk_security;
	307	sid = ssec->sid;
	308	}
	309	else
	310	sid = SECSID_NULL;
d28d1e08	311
cb969f07	312	err = selinux_xfrm_sec_ctx_alloc(&xp->security, uctx, NULL, sid);
d28d1e08 TJ	313	return err;
	314	}
	315
	316
	317	/*
	318	* LSM hook implementation that copies security data structure from old to
	319	* new for policy cloning.
	320	*/
	321	int selinux_xfrm_policy_clone(struct xfrm_policy old, struct xfrm_policy new)
	322	{
	323	struct xfrm_sec_ctx old_ctx, new_ctx;
	324
	325	old_ctx = old->security;
	326
	327	if (old_ctx) {
	328	new_ctx = new->security = kmalloc(sizeof(*new_ctx) +
	329	old_ctx->ctx_len,
	330	GFP_KERNEL);
	331
	332	if (!new_ctx)
	333	return -ENOMEM;
	334
	335	memcpy(new_ctx, old_ctx, sizeof(*new_ctx));
	336	memcpy(new_ctx->ctx_str, old_ctx->ctx_str, new_ctx->ctx_len);
	337	}
	338	return 0;
	339	}
	340
	341	/*
	342	* LSM hook implementation that frees xfrm_policy security information.
	343	*/
	344	void selinux_xfrm_policy_free(struct xfrm_policy *xp)
	345	{
	346	struct xfrm_sec_ctx *ctx = xp->security;
	347	if (ctx)
	348	kfree(ctx);
	349	}
	350
c8c05a8e CZ	351	/*
	352	* LSM hook implementation that authorizes deletion of labeled policies.
	353	*/
	354	int selinux_xfrm_policy_delete(struct xfrm_policy *xp)
	355	{
	356	struct task_security_struct *tsec = current->security;
	357	struct xfrm_sec_ctx *ctx = xp->security;
	358	int rc = 0;
	359
	360	if (ctx)
	361	rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
	362	SECCLASS_ASSOCIATION,
	363	ASSOCIATION__SETCONTEXT, NULL);
	364
	365	return rc;
	366	}
	367
d28d1e08 TJ	368	/*
	369	* LSM hook implementation that allocs and transfers sec_ctx spec to
	370	* xfrm_state.
	371	*/
e0d1caa7 VY	372	int selinux_xfrm_state_alloc(struct xfrm_state x, struct xfrm_user_sec_ctx uctx,
e0d1caa7 VY	373	struct xfrm_sec_ctx *pol, u32 secid)
d28d1e08 TJ	374	{
	375	int err;
	376
	377	BUG_ON(!x);
	378
e0d1caa7	379	err = selinux_xfrm_sec_ctx_alloc(&x->security, uctx, pol, secid);
d28d1e08 TJ	380	return err;
	381	}
	382
	383	/*
	384	* LSM hook implementation that frees xfrm_state security information.
	385	*/
	386	void selinux_xfrm_state_free(struct xfrm_state *x)
	387	{
	388	struct xfrm_sec_ctx *ctx = x->security;
	389	if (ctx)
	390	kfree(ctx);
	391	}
	392
2c7946a7 CZ	393	/*
	394	* SELinux internal function to retrieve the context of a connected
	395	* (sk->sk_state == TCP_ESTABLISHED) TCP socket based on its security
	396	* association used to connect to the remote socket.
	397	*
	398	* Retrieve via getsockopt SO_PEERSEC.
	399	*/
	400	u32 selinux_socket_getpeer_stream(struct sock *sk)
	401	{
	402	struct dst_entry dst, dst_test;
	403	u32 peer_sid = SECSID_NULL;
	404
	405	if (sk->sk_state != TCP_ESTABLISHED)
	406	goto out;
	407
	408	dst = sk_dst_get(sk);
	409	if (!dst)
	410	goto out;
	411
	412	for (dst_test = dst; dst_test != 0;
	413	dst_test = dst_test->child) {
	414	struct xfrm_state *x = dst_test->xfrm;
	415
	416	if (x && selinux_authorizable_xfrm(x)) {
	417	struct xfrm_sec_ctx *ctx = x->security;
	418	peer_sid = ctx->ctx_sid;
	419	break;
	420	}
	421	}
	422	dst_release(dst);
	423
	424	out:
	425	return peer_sid;
	426	}
	427
	428	/*
	429	* SELinux internal function to retrieve the context of a UDP packet
	430	* based on its security association used to connect to the remote socket.
	431	*
	432	* Retrieve via setsockopt IP_PASSSEC and recvmsg with control message
	433	* type SCM_SECURITY.
	434	*/
	435	u32 selinux_socket_getpeer_dgram(struct sk_buff *skb)
	436	{
	437	struct sec_path *sp;
	438
	439	if (skb == NULL)
	440	return SECSID_NULL;
	441
	442	if (skb->sk->sk_protocol != IPPROTO_UDP)
	443	return SECSID_NULL;
	444
	445	sp = skb->sp;
	446	if (sp) {
	447	int i;
	448
	449	for (i = sp->len-1; i >= 0; i--) {
67644726	450	struct xfrm_state *x = sp->xvec[i];
2c7946a7 CZ	451	if (selinux_authorizable_xfrm(x)) {
	452	struct xfrm_sec_ctx *ctx = x->security;
	453	return ctx->ctx_sid;
	454	}
	455	}
	456	}
	457
	458	return SECSID_NULL;
	459	}
	460
c8c05a8e CZ	461	/*
	462	* LSM hook implementation that authorizes deletion of labeled SAs.
	463	*/
	464	int selinux_xfrm_state_delete(struct xfrm_state *x)
	465	{
	466	struct task_security_struct *tsec = current->security;
	467	struct xfrm_sec_ctx *ctx = x->security;
	468	int rc = 0;
	469
	470	if (ctx)
	471	rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
	472	SECCLASS_ASSOCIATION,
	473	ASSOCIATION__SETCONTEXT, NULL);
	474
	475	return rc;
	476	}
	477
d28d1e08 TJ	478	/*
	479	* LSM hook that controls access to unlabelled packets. If
	480	* a xfrm_state is authorizable (defined by macro) then it was
	481	* already authorized by the IPSec process. If not, then
	482	* we need to check for unlabelled access since this may not have
	483	* gone thru the IPSec process.
	484	*/
e0d1caa7 VY	485	int selinux_xfrm_sock_rcv_skb(u32 isec_sid, struct sk_buff *skb,
e0d1caa7 VY	486	struct avc_audit_data *ad)
d28d1e08 TJ	487	{
	488	int i, rc = 0;
	489	struct sec_path *sp;
e0d1caa7	490	u32 sel_sid = SECINITSID_UNLABELED;
d28d1e08 TJ	491
	492	sp = skb->sp;
	493
	494	if (sp) {
d28d1e08	495	for (i = 0; i < sp->len; i++) {
67644726	496	struct xfrm_state *x = sp->xvec[i];
d28d1e08	497
e0d1caa7 VY	498	if (x && selinux_authorizable_xfrm(x)) {
	499	struct xfrm_sec_ctx *ctx = x->security;
	500	sel_sid = ctx->ctx_sid;
	501	break;
	502	}
d28d1e08 TJ	503	}
	504	}
	505
e0d1caa7 VY	506	rc = avc_has_perm(isec_sid, sel_sid, SECCLASS_ASSOCIATION,
e0d1caa7 VY	507	ASSOCIATION__RECVFROM, ad);
d28d1e08	508
d28d1e08 TJ	509	return rc;
	510	}
	511
	512	/*
	513	* POSTROUTE_LAST hook's XFRM processing:
	514	* If we have no security association, then we need to determine
	515	* whether the socket is allowed to send to an unlabelled destination.
	516	* If we do have a authorizable security association, then it has already been
	517	* checked in xfrm_policy_lookup hook.
	518	*/
e0d1caa7 VY	519	int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb,
e0d1caa7 VY	520	struct avc_audit_data *ad)
d28d1e08 TJ	521	{
	522	struct dst_entry *dst;
	523	int rc = 0;
	524
	525	dst = skb->dst;
	526
	527	if (dst) {
	528	struct dst_entry *dst_test;
	529
	530	for (dst_test = dst; dst_test != 0;
	531	dst_test = dst_test->child) {
	532	struct xfrm_state *x = dst_test->xfrm;
	533
	534	if (x && selinux_authorizable_xfrm(x))
4e5ab4cb	535	goto out;
d28d1e08 TJ	536	}
	537	}
	538
	539	rc = avc_has_perm(isec_sid, SECINITSID_UNLABELED, SECCLASS_ASSOCIATION,
e0d1caa7	540	ASSOCIATION__SENDTO, ad);
4e5ab4cb JM	541	out:
4e5ab4cb JM	542	return rc;
d28d1e08	543	}