xfrm_user.c

linux 内核源代码

/* xfrm_user.c: User interface to configure xfrm engine.
 *
 * Copyright (C) 2002 David S. Miller ([e-mail])
 *
 * Changes:
 *	Mitsuru KANDA @USAGI
 * 	Kazunori MIYAZAWA @USAGI
 * 	Kunihiro Ishiguro <[e-mail]>
 * 		IPv6 support
 *
 */

#include <linux/crypto.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/socket.h>
#include <linux/string.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/pfkeyv2.h>
#include <linux/ipsec.h>
#include <linux/init.h>
#include <linux/security.h>
#include <net/sock.h>
#include <net/xfrm.h>
#include <net/netlink.h>
#include <asm/uaccess.h>
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
#include <linux/in6.h>
#endif

static int verify_one_alg(struct nlattr **attrs, enum xfrm_attr_type_t type)
{
	struct nlattr *rt = attrs[type];
	struct xfrm_algo *algp;

	if (!rt)
		return 0;

	algp = nla_data(rt);
	if (nla_len(rt) < xfrm_alg_len(algp))
		return -EINVAL;

	switch (type) {
	case XFRMA_ALG_AUTH:
		if (!algp->alg_key_len &&
		    strcmp(algp->alg_name, "digest_null") != 0)
			return -EINVAL;
		break;

	case XFRMA_ALG_CRYPT:
		if (!algp->alg_key_len &&
		    strcmp(algp->alg_name, "cipher_null") != 0)
			return -EINVAL;
		break;

	case XFRMA_ALG_COMP:
		/* Zero length keys are legal.  */
		break;

	default:
		return -EINVAL;
	}

	algp->alg_name[CRYPTO_MAX_ALG_NAME - 1] = '\0';
	return 0;
}

static void verify_one_addr(struct nlattr **attrs, enum xfrm_attr_type_t type,
			   xfrm_address_t **addrp)
{
	struct nlattr *rt = attrs[type];

	if (rt && addrp)
		*addrp = nla_data(rt);
}

static inline int verify_sec_ctx_len(struct nlattr **attrs)
{
	struct nlattr *rt = attrs[XFRMA_SEC_CTX];
	struct xfrm_user_sec_ctx *uctx;

	if (!rt)
		return 0;

	uctx = nla_data(rt);
	if (uctx->len != (sizeof(struct xfrm_user_sec_ctx) + uctx->ctx_len))
		return -EINVAL;

	return 0;
}


static int verify_newsa_info(struct xfrm_usersa_info *p,
			     struct nlattr **attrs)
{
	int err;

	err = -EINVAL;
	switch (p->family) {
	case AF_INET:
		break;

	case AF_INET6:
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
		break;
#else
		err = -EAFNOSUPPORT;
		goto out;
#endif

	default:
		goto out;
	}

	err = -EINVAL;
	switch (p->id.proto) {
	case IPPROTO_AH:
		if (!attrs[XFRMA_ALG_AUTH]	||
		    attrs[XFRMA_ALG_CRYPT]	||
		    attrs[XFRMA_ALG_COMP])
			goto out;
		break;

	case IPPROTO_ESP:
		if ((!attrs[XFRMA_ALG_AUTH] &&
		     !attrs[XFRMA_ALG_CRYPT])	||
		    attrs[XFRMA_ALG_COMP])
			goto out;
		break;

	case IPPROTO_COMP:
		if (!attrs[XFRMA_ALG_COMP]	||
		    attrs[XFRMA_ALG_AUTH]	||
		    attrs[XFRMA_ALG_CRYPT])
			goto out;
		break;

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
	case IPPROTO_DSTOPTS:
	case IPPROTO_ROUTING:
		if (attrs[XFRMA_ALG_COMP]	||
		    attrs[XFRMA_ALG_AUTH]	||
		    attrs[XFRMA_ALG_CRYPT]	||
		    attrs[XFRMA_ENCAP]		||
		    attrs[XFRMA_SEC_CTX]	||
		    !attrs[XFRMA_COADDR])
			goto out;
		break;
#endif

	default:
		goto out;
	}

	if ((err = verify_one_alg(attrs, XFRMA_ALG_AUTH)))
		goto out;
	if ((err = verify_one_alg(attrs, XFRMA_ALG_CRYPT)))
		goto out;
	if ((err = verify_one_alg(attrs, XFRMA_ALG_COMP)))
		goto out;
	if ((err = verify_sec_ctx_len(attrs)))
		goto out;

	err = -EINVAL;
	switch (p->mode) {
	case XFRM_MODE_TRANSPORT:
	case XFRM_MODE_TUNNEL:
	case XFRM_MODE_ROUTEOPTIMIZATION:
	case XFRM_MODE_BEET:
		break;

	default:
		goto out;
	}

	err = 0;

out:
	return err;
}

static int attach_one_algo(struct xfrm_algo **algpp, u8 *props,
			   struct xfrm_algo_desc *(*get_byname)(char *, int),
			   struct nlattr *rta)
{
	struct xfrm_algo *p, *ualg;
	struct xfrm_algo_desc *algo;

	if (!rta)
		return 0;

	ualg = nla_data(rta);

	algo = get_byname(ualg->alg_name, 1);
	if (!algo)
		return -ENOSYS;
	*props = algo->desc.sadb_alg_id;

	p = kmemdup(ualg, xfrm_alg_len(ualg), GFP_KERNEL);
	if (!p)
		return -ENOMEM;

	strcpy(p->alg_name, algo->name);
	*algpp = p;
	return 0;
}

static inline int xfrm_user_sec_ctx_size(struct xfrm_sec_ctx *xfrm_ctx)
{
	int len = 0;

	if (xfrm_ctx) {
		len += sizeof(struct xfrm_user_sec_ctx);
		len += xfrm_ctx->ctx_len;
	}
	return len;
}

static void copy_from_user_state(struct xfrm_state *x, struct xfrm_usersa_info *p)
{
	memcpy(&x->id, &p->id, sizeof(x->id));
	memcpy(&x->sel, &p->sel, sizeof(x->sel));
	memcpy(&x->lft, &p->lft, sizeof(x->lft));
	x->props.mode = p->mode;
	x->props.replay_window = p->replay_window;
	x->props.reqid = p->reqid;
	x->props.family = p->family;
	memcpy(&x->props.saddr, &p->saddr, sizeof(x->props.saddr));
	x->props.flags = p->flags;

	/*
	 * Set inner address family if the KM left it as zero.
	 * See comment in validate_tmpl.
	 */
	if (!x->sel.family)
		x->sel.family = p->family;
}

/*
 * someday when pfkey also has support, we could have the code
 * somehow made shareable and move it to xfrm_state.c - JHS
 *
*/
static void xfrm_update_ae_params(struct xfrm_state *x, struct nlattr **attrs)
{
	struct nlattr *rp = attrs[XFRMA_REPLAY_VAL];
	struct nlattr *lt = attrs[XFRMA_LTIME_VAL];
	struct nlattr *et = attrs[XFRMA_ETIMER_THRESH];
	struct nlattr *rt = attrs[XFRMA_REPLAY_THRESH];

	if (rp) {
		struct xfrm_replay_state *replay;
		replay = nla_data(rp);
		memcpy(&x->replay, replay, sizeof(*replay));
		memcpy(&x->preplay, replay, sizeof(*replay));
	}

	if (lt) {
		struct xfrm_lifetime_cur *ltime;
		ltime = nla_data(lt);
		x->curlft.bytes = ltime->bytes;
		x->curlft.packets = ltime->packets;
		x->curlft.add_time = ltime->add_time;
		x->curlft.use_time = ltime->use_time;
	}

	if (et)
		x->replay_maxage = nla_get_u32(et);

	if (rt)
		x->replay_maxdiff = nla_get_u32(rt);
}

static struct xfrm_state *xfrm_state_construct(struct xfrm_usersa_info *p,
					       struct nlattr **attrs,
					       int *errp)
{
	struct xfrm_state *x = xfrm_state_alloc();
	int err = -ENOMEM;

	if (!x)
		goto error_no_put;

	copy_from_user_state(x, p);

	if ((err = attach_one_algo(&x->aalg, &x->props.aalgo,
				   xfrm_aalg_get_byname,
				   attrs[XFRMA_ALG_AUTH])))
		goto error;
	if ((err = attach_one_algo(&x->ealg, &x->props.ealgo,
				   xfrm_ealg_get_byname,
				   attrs[XFRMA_ALG_CRYPT])))
		goto error;
	if ((err = attach_one_algo(&x->calg, &x->props.calgo,
				   xfrm_calg_get_byname,
				   attrs[XFRMA_ALG_COMP])))
		goto error;

	if (attrs[XFRMA_ENCAP]) {
		x->encap = kmemdup(nla_data(attrs[XFRMA_ENCAP]),
				   sizeof(*x->encap), GFP_KERNEL);
		if (x->encap == NULL)
			goto error;
	}

	if (attrs[XFRMA_COADDR]) {
		x->coaddr = kmemdup(nla_data(attrs[XFRMA_COADDR]),
				    sizeof(*x->coaddr), GFP_KERNEL);
		if (x->coaddr == NULL)
			goto error;
	}

	err = xfrm_init_state(x);
	if (err)
		goto error;

	if (attrs[XFRMA_SEC_CTX] &&
	    security_xfrm_state_alloc(x, nla_data(attrs[XFRMA_SEC_CTX])))
		goto error;

	x->km.seq = p->seq;
	x->replay_maxdiff = sysctl_xfrm_aevent_rseqth;
	/* sysctl_xfrm_aevent_etime is in 100ms units */
	x->replay_maxage = (sysctl_xfrm_aevent_etime*HZ)/XFRM_AE_ETH_M;
	x->preplay.bitmap = 0;
	x->preplay.seq = x->replay.seq+x->replay_maxdiff;
	x->preplay.oseq = x->replay.oseq +x->replay_maxdiff;

	/* override default values from above */

	xfrm_update_ae_params(x, attrs);

	return x;

error:
	x->km.state = XFRM_STATE_DEAD;
	xfrm_state_put(x);
error_no_put:
	*errp = err;
	return NULL;
}

static int xfrm_add_sa(struct sk_buff *skb, struct nlmsghdr *nlh,
		struct nlattr **attrs)
{
	struct xfrm_usersa_info *p = nlmsg_data(nlh);
	struct xfrm_state *x;
	int err;
	struct km_event c;

	err = verify_newsa_info(p, attrs);
	if (err)
		return err;

	x = xfrm_state_construct(p, attrs, &err);
	if (!x)
		return err;

	xfrm_state_hold(x);
	if (nlh->nlmsg_type == XFRM_MSG_NEWSA)
		err = xfrm_state_add(x);
	else
		err = xfrm_state_update(x);

	xfrm_audit_state_add(x, err ? 0 : 1, NETLINK_CB(skb).loginuid,
			     NETLINK_CB(skb).sid);

	if (err < 0) {
		x->km.state = XFRM_STATE_DEAD;
		__xfrm_state_put(x);
		goto out;
	}

	c.seq = nlh->nlmsg_seq;
	c.pid = nlh->nlmsg_pid;
	c.event = nlh->nlmsg_type;

	km_state_notify(x, &c);
out:
	xfrm_state_put(x);
	return err;
}

static struct xfrm_state *xfrm_user_state_lookup(struct xfrm_usersa_id *p,
						 struct nlattr **attrs,
						 int *errp)
{
	struct xfrm_state *x = NULL;
	int err;

	if (xfrm_id_proto_match(p->proto, IPSEC_PROTO_ANY)) {
		err = -ESRCH;
		x = xfrm_state_lookup(&p->daddr, p->spi, p->proto, p->family);
	} else {
		xfrm_address_t *saddr = NULL;

		verify_one_addr(attrs, XFRMA_SRCADDR, &saddr);
		if (!saddr) {
			err = -EINVAL;
			goto out;
		}

		err = -ESRCH;
		x = xfrm_state_lookup_byaddr(&p->daddr, saddr, p->proto,
					     p->family);
	}

 out:
	if (!x && errp)
		*errp = err;
	return x;
}

static int xfrm_del_sa(struct sk_buff *skb, struct nlmsghdr *nlh,
		struct nlattr **attrs)
{
	struct xfrm_state *x;
	int err = -ESRCH;
	struct km_event c;
	struct xfrm_usersa_id *p = nlmsg_data(nlh);

	x = xfrm_user_state_lookup(p, attrs, &err);
	if (x == NULL)
		return err;

	if ((err = security_xfrm_state_delete(x)) != 0)
		goto out;

	if (xfrm_state_kern(x)) {
		err = -EPERM;
		goto out;
	}

	err = xfrm_state_delete(x);

	if (err < 0)
		goto out;

	c.seq = nlh->nlmsg_seq;
	c.pid = nlh->nlmsg_pid;
	c.event = nlh->nlmsg_type;
	km_state_notify(x, &c);

out:
	xfrm_audit_state_delete(x, err ? 0 : 1, NETLINK_CB(skb).loginuid,
				NETLINK_CB(skb).sid);
	xfrm_state_put(x);
	return err;
}

static void copy_to_user_state(struct xfrm_state *x, struct xfrm_usersa_info *p)
{
	memcpy(&p->id, &x->id, sizeof(p->id));
	memcpy(&p->sel, &x->sel, sizeof(p->sel));
	memcpy(&p->lft, &x->lft, sizeof(p->lft));
	memcpy(&p->curlft, &x->curlft, sizeof(p->curlft));
	memcpy(&p->stats, &x->stats, sizeof(p->stats));
	memcpy(&p->saddr, &x->props.saddr, sizeof(p->saddr));
	p->mode = x->props.mode;
	p->replay_window = x->props.replay_window;
	p->reqid = x->props.reqid;
	p->family = x->props.family;
	p->flags = x->props.flags;
	p->seq = x->km.seq;
}

struct xfrm_dump_info {
	struct sk_buff *in_skb;
	struct sk_buff *out_skb;
	u32 nlmsg_seq;
	u16 nlmsg_flags;
	int start_idx;
	int this_idx;
};

static int copy_sec_ctx(struct xfrm_sec_ctx *s, struct sk_buff *skb)
{
	struct xfrm_user_sec_ctx *uctx;
	struct nlattr *attr;
	int ctx_size = sizeof(*uctx) + s->ctx_len;

	attr = nla_reserve(skb, XFRMA_SEC_CTX, ctx_size);
	if (attr == NULL)
		return -EMSGSIZE;

	uctx = nla_data(attr);
	uctx->exttype = XFRMA_SEC_CTX;
	uctx->len = ctx_size;
	uctx->ctx_doi = s->ctx_doi;
	uctx->ctx_alg = s->ctx_alg;
	uctx->ctx_len = s->ctx_len;
	memcpy(uctx + 1, s->ctx_str, s->ctx_len);

	return 0;
}

/* Don't change this without updating xfrm_sa_len! */
static int copy_to_user_state_extra(struct xfrm_state *x,
				    struct xfrm_usersa_info *p,
				    struct sk_buff *skb)
{
	copy_to_user_state(x, p);

	if (x->coaddr)
		NLA_PUT(skb, XFRMA_COADDR, sizeof(*x->coaddr), x->coaddr);

	if (x->lastused)
		NLA_PUT_U64(skb, XFRMA_LASTUSED, x->lastused);

	if (x->aalg)
		NLA_PUT(skb, XFRMA_ALG_AUTH, xfrm_alg_len(x->aalg), x->aalg);
	if (x->ealg)
		NLA_PUT(skb, XFRMA_ALG_CRYPT, xfrm_alg_len(x->ealg), x->ealg);
	if (x->calg)
		NLA_PUT(skb, XFRMA_ALG_COMP, sizeof(*(x->calg)), x->calg);

	if (x->encap)
		NLA_PUT(skb, XFRMA_ENCAP, sizeof(*x->encap), x->encap);

	if (x->security && copy_sec_ctx(x->security, skb) < 0)
		goto nla_put_failure;

	return 0;

nla_put_failure:
	return -EMSGSIZE;
}

static int dump_one_state(struct xfrm_state *x, int count, void *ptr)
{
	struct xfrm_dump_info *sp = ptr;
	struct sk_buff *in_skb = sp->in_skb;
	struct sk_buff *skb = sp->out_skb;
	struct xfrm_usersa_info *p;
	struct nlmsghdr *nlh;
	int err;

	if (sp->this_idx < sp->start_idx)
		goto out;

	nlh = nlmsg_put(skb, NETLINK_CB(in_skb).pid, sp->nlmsg_seq,
			XFRM_MSG_NEWSA, sizeof(*p), sp->nlmsg_flags);
	if (nlh == NULL)
		return -EMSGSIZE;

	p = nlmsg_data(nlh);

	err = copy_to_user_state_extra(x, p, skb);
	if (err)
		goto nla_put_failure;

	nlmsg_end(skb, nlh);
out:
	sp->this_idx++;
	return 0;

nla_put_failure:
	nlmsg_cancel(skb, nlh);
	return err;
}

static int xfrm_dump_sa(struct sk_buff *skb, struct netlink_callback *cb)
{
	struct xfrm_dump_info info;

	info.in_skb = cb->skb;
	info.out_skb = skb;
	info.nlmsg_seq = cb->nlh->nlmsg_seq;
	info.nlmsg_flags = NLM_F_MULTI;
	info.this_idx = 0;
	info.start_idx = cb->args[0];
	(void) xfrm_state_walk(0, dump_one_state, &info);
	cb->args[0] = info.this_idx;

	return skb->len;
}

static struct sk_buff *xfrm_state_netlink(struct sk_buff *in_skb,
					  struct xfrm_state *x, u32 seq)
{
	struct xfrm_dump_info info;
	struct sk_buff *skb;

	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
	if (!skb)
		return ERR_PTR(-ENOMEM);

	info.in_skb = in_skb;
	info.out_skb = skb;
	info.nlmsg_seq = seq;
	info.nlmsg_flags = 0;
	info.this_idx = info.start_idx = 0;

	if (dump_one_state(x, 0, &info)) {
		kfree_skb(skb);
		return NULL;
	}

	return skb;
}

static inline size_t xfrm_spdinfo_msgsize(void)
{
	return NLMSG_ALIGN(4)
	       + nla_total_size(sizeof(struct xfrmu_spdinfo))