xfrm: MIGRATE enhancements (draft-ebalard-mext-pfkey-enhanced-migrate)

Provides implementation of the enhancements of XFRM/PF_KEY MIGRATE mechanism
specified in draft-ebalard-mext-pfkey-enhanced-migrate-00. Defines associated
PF_KEY SADB_X_EXT_KMADDRESS extension and XFRM/netlink XFRMA_KMADDRESS
attribute.
Signed-off-by: Arnaud Ebalard <arno@natisbad.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/pfkeyv2.h

@@ -226,6 +226,15 @@ struct sadb_x_sec_ctx {
 } __attribute__((packed));
 /* sizeof(struct sadb_sec_ctx) = 8 */
 
+/* Used by MIGRATE to pass addresses IKE will use to perform
+ * negotiation with the peer */
+struct sadb_x_kmaddress {
+	uint16_t	sadb_x_kmaddress_len;
+	uint16_t	sadb_x_kmaddress_exttype;
+	uint32_t	sadb_x_kmaddress_reserved;
+} __attribute__((packed));
+/* sizeof(struct sadb_x_kmaddress) == 8 */
+
 /* Message types */
 #define SADB_RESERVED		0
 #define SADB_GETSPI		1
@@ -346,7 +355,9 @@ struct sadb_x_sec_ctx {
 #define SADB_X_EXT_NAT_T_DPORT		22
 #define SADB_X_EXT_NAT_T_OA		23
 #define SADB_X_EXT_SEC_CTX		24
-#define SADB_EXT_MAX			24
+/* Used with MIGRATE to pass @ to IKE for negotiation */
+#define SADB_X_EXT_KMADDRESS		25
+#define SADB_EXT_MAX			25
 
 /* Identity Extension values */
 #define SADB_IDENTTYPE_RESERVED	0

include/linux/xfrm.h

@@ -279,6 +279,7 @@ enum xfrm_attr_type_t {
 	XFRMA_POLICY_TYPE,	/* struct xfrm_userpolicy_type */
 	XFRMA_MIGRATE,
 	XFRMA_ALG_AEAD,		/* struct xfrm_algo_aead */
+	XFRMA_KMADDRESS,        /* struct xfrm_user_kmaddress */
 	__XFRMA_MAX
 
 #define XFRMA_MAX (__XFRMA_MAX - 1)
@@ -415,6 +416,15 @@ struct xfrm_user_report {
 	struct xfrm_selector		sel;
 };
 
+/* Used by MIGRATE to pass addresses IKE should use to perform
+ * SA negotiation with the peer */
+struct xfrm_user_kmaddress {
+	xfrm_address_t                  local;
+	xfrm_address_t                  remote;
+	__u32				reserved;
+	__u16				family;
+};
+
 struct xfrm_user_migrate {
 	xfrm_address_t			old_daddr;
 	xfrm_address_t			old_saddr;

include/net/xfrm.h

@@ -492,6 +492,13 @@ struct xfrm_policy
 	struct xfrm_tmpl       	xfrm_vec[XFRM_MAX_DEPTH];
 };
 
+struct xfrm_kmaddress {
+	xfrm_address_t          local;
+	xfrm_address_t          remote;
+	u32			reserved;
+	u16			family;
+};
+
 struct xfrm_migrate {
 	xfrm_address_t		old_daddr;
 	xfrm_address_t		old_saddr;
@@ -531,7 +538,7 @@ struct xfrm_mgr
 	int			(*new_mapping)(struct xfrm_state *x, xfrm_address_t *ipaddr, __be16 sport);
 	int			(*notify_policy)(struct xfrm_policy *x, int dir, struct km_event *c);
 	int			(*report)(u8 proto, struct xfrm_selector *sel, xfrm_address_t *addr);
-	int			(*migrate)(struct xfrm_selector *sel, u8 dir, u8 type, struct xfrm_migrate *m, int num_bundles);
+	int			(*migrate)(struct xfrm_selector *sel, u8 dir, u8 type, struct xfrm_migrate *m, int num_bundles, struct xfrm_kmaddress *k);
 };
 
 extern int xfrm_register_km(struct xfrm_mgr *km);
@@ -1432,12 +1439,14 @@ extern int xfrm_bundle_ok(struct xfrm_policy *pol, struct xfrm_dst *xdst,
 
 #ifdef CONFIG_XFRM_MIGRATE
 extern int km_migrate(struct xfrm_selector *sel, u8 dir, u8 type,
-		      struct xfrm_migrate *m, int num_bundles);
+		      struct xfrm_migrate *m, int num_bundles,
+		      struct xfrm_kmaddress *k);
 extern struct xfrm_state * xfrm_migrate_state_find(struct xfrm_migrate *m);
 extern struct xfrm_state * xfrm_state_migrate(struct xfrm_state *x,
 					      struct xfrm_migrate *m);
 extern int xfrm_migrate(struct xfrm_selector *sel, u8 dir, u8 type,
-			struct xfrm_migrate *m, int num_bundles);
+			struct xfrm_migrate *m, int num_bundles,
+			struct xfrm_kmaddress *k);
 #endif
 
 extern wait_queue_head_t km_waitq;

net/key/af_key.c

@@ -398,6 +398,7 @@ static u8 sadb_ext_min_len[] = {
 	[SADB_X_EXT_NAT_T_DPORT]	= (u8) sizeof(struct sadb_x_nat_t_port),
 	[SADB_X_EXT_NAT_T_OA]		= (u8) sizeof(struct sadb_address),
 	[SADB_X_EXT_SEC_CTX]		= (u8) sizeof(struct sadb_x_sec_ctx),
+	[SADB_X_EXT_KMADDRESS]		= (u8) sizeof(struct sadb_x_kmaddress),
 };
 
 /* Verify sadb_address_{len,prefixlen} against sa_family.  */
@@ -2384,24 +2385,21 @@ static int pfkey_sockaddr_pair_size(sa_family_t family)
 	return PFKEY_ALIGN8(pfkey_sockaddr_len(family) * 2);
 }
 
-static int parse_sockaddr_pair(struct sadb_x_ipsecrequest *rq,
+static int parse_sockaddr_pair(struct sockaddr *sa, int ext_len,
 			       xfrm_address_t *saddr, xfrm_address_t *daddr,
 			       u16 *family)
 {
-	u8 *sa = (u8 *) (rq + 1);
 	int af, socklen;
 
-	if (rq->sadb_x_ipsecrequest_len <
-	    pfkey_sockaddr_pair_size(((struct sockaddr *)sa)->sa_family))
+	if (ext_len < pfkey_sockaddr_pair_size(sa->sa_family))
 		return -EINVAL;
 
-	af = pfkey_sockaddr_extract((struct sockaddr *) sa,
-				    saddr);
+	af = pfkey_sockaddr_extract(sa, saddr);
 	if (!af)
 		return -EINVAL;
 
 	socklen = pfkey_sockaddr_len(af);
-	if (pfkey_sockaddr_extract((struct sockaddr *) (sa + socklen),
+	if (pfkey_sockaddr_extract((struct sockaddr *) (((u8 *)sa) + socklen),
 				   daddr) != af)
 		return -EINVAL;
 
@@ -2421,7 +2419,9 @@ static int ipsecrequests_to_migrate(struct sadb_x_ipsecrequest *rq1, int len,
 		return -EINVAL;
 
 	/* old endoints */
-	err = parse_sockaddr_pair(rq1, &m->old_saddr, &m->old_daddr,
+	err = parse_sockaddr_pair((struct sockaddr *)(rq1 + 1),
+				  rq1->sadb_x_ipsecrequest_len,
+				  &m->old_saddr, &m->old_daddr,
 				  &m->old_family);
 	if (err)
 		return err;
@@ -2434,7 +2434,9 @@ static int ipsecrequests_to_migrate(struct sadb_x_ipsecrequest *rq1, int len,
 		return -EINVAL;
 
 	/* new endpoints */
-	err = parse_sockaddr_pair(rq2, &m->new_saddr, &m->new_daddr,
+	err = parse_sockaddr_pair((struct sockaddr *)(rq2 + 1),
+				  rq2->sadb_x_ipsecrequest_len,
+				  &m->new_saddr, &m->new_daddr,
 				  &m->new_family);
 	if (err)
 		return err;
@@ -2460,29 +2462,40 @@ static int pfkey_migrate(struct sock *sk, struct sk_buff *skb,
 	int i, len, ret, err = -EINVAL;
 	u8 dir;
 	struct sadb_address *sa;
+	struct sadb_x_kmaddress *kma;
 	struct sadb_x_policy *pol;
 	struct sadb_x_ipsecrequest *rq;
 	struct xfrm_selector sel;
 	struct xfrm_migrate m[XFRM_MAX_DEPTH];
+	struct xfrm_kmaddress k;
 
 	if (!present_and_same_family(ext_hdrs[SADB_EXT_ADDRESS_SRC - 1],
-	    ext_hdrs[SADB_EXT_ADDRESS_DST - 1]) ||
+				     ext_hdrs[SADB_EXT_ADDRESS_DST - 1]) ||
 	    !ext_hdrs[SADB_X_EXT_POLICY - 1]) {
 		err = -EINVAL;
 		goto out;
 	}
 
+	kma = ext_hdrs[SADB_X_EXT_KMADDRESS - 1];
 	pol = ext_hdrs[SADB_X_EXT_POLICY - 1];
-	if (!pol) {
-		err = -EINVAL;
-		goto out;
-	}
 
 	if (pol->sadb_x_policy_dir >= IPSEC_DIR_MAX) {
 		err = -EINVAL;
 		goto out;
 	}
 
+	if (kma) {
+		/* convert sadb_x_kmaddress to xfrm_kmaddress */
+		k.reserved = kma->sadb_x_kmaddress_reserved;
+		ret = parse_sockaddr_pair((struct sockaddr *)(kma + 1),
+					  8*(kma->sadb_x_kmaddress_len) - sizeof(*kma),
+					  &k.local, &k.remote, &k.family);
+		if (ret < 0) {
+			err = ret;
+			goto out;
+		}
+	}
+
 	dir = pol->sadb_x_policy_dir - 1;
 	memset(&sel, 0, sizeof(sel));
 
@@ -2527,7 +2540,8 @@ static int pfkey_migrate(struct sock *sk, struct sk_buff *skb,
 		goto out;
 	}
 
-	return xfrm_migrate(&sel, dir, XFRM_POLICY_TYPE_MAIN, m, i);
+	return xfrm_migrate(&sel, dir, XFRM_POLICY_TYPE_MAIN, m, i,
+			    kma ? &k : NULL);
 
  out:
 	return err;
@@ -3319,6 +3333,32 @@ static int set_sadb_address(struct sk_buff *skb, int sasize, int type,
 	return 0;
 }
 
+
+static int set_sadb_kmaddress(struct sk_buff *skb, struct xfrm_kmaddress *k)
+{
+	struct sadb_x_kmaddress *kma;
+	u8 *sa;
+	int family = k->family;
+	int socklen = pfkey_sockaddr_len(family);
+	int size_req;
+
+	size_req = (sizeof(struct sadb_x_kmaddress) +
+		    pfkey_sockaddr_pair_size(family));
+
+	kma = (struct sadb_x_kmaddress *)skb_put(skb, size_req);
+	memset(kma, 0, size_req);
+	kma->sadb_x_kmaddress_len = size_req / 8;
+	kma->sadb_x_kmaddress_exttype = SADB_X_EXT_KMADDRESS;
+	kma->sadb_x_kmaddress_reserved = k->reserved;
+
+	sa = (u8 *)(kma + 1);
+	if (!pfkey_sockaddr_fill(&k->local, 0, (struct sockaddr *)sa, family) ||
+	    !pfkey_sockaddr_fill(&k->remote, 0, (struct sockaddr *)(sa+socklen), family))
+		return -EINVAL;
+
+	return 0;
+}
+
 static int set_ipsecrequest(struct sk_buff *skb,
 			    uint8_t proto, uint8_t mode, int level,
 			    uint32_t reqid, uint8_t family,
@@ -3351,7 +3391,8 @@ static int set_ipsecrequest(struct sk_buff *skb,
 
 #ifdef CONFIG_NET_KEY_MIGRATE
 static int pfkey_send_migrate(struct xfrm_selector *sel, u8 dir, u8 type,
-			      struct xfrm_migrate *m, int num_bundles)
+			      struct xfrm_migrate *m, int num_bundles,
+			      struct xfrm_kmaddress *k)
 {
 	int i;
 	int sasize_sel;
@@ -3368,6 +3409,12 @@ static int pfkey_send_migrate(struct xfrm_selector *sel, u8 dir, u8 type,
 	if (num_bundles <= 0 || num_bundles > XFRM_MAX_DEPTH)
 		return -EINVAL;
 
+	if (k != NULL) {
+		/* addresses for KM */
+		size += PFKEY_ALIGN8(sizeof(struct sadb_x_kmaddress) +
+				     pfkey_sockaddr_pair_size(k->family));
+	}
+
 	/* selector */
 	sasize_sel = pfkey_sockaddr_size(sel->family);
 	if (!sasize_sel)
@@ -3404,6 +3451,10 @@ static int pfkey_send_migrate(struct xfrm_selector *sel, u8 dir, u8 type,
 	hdr->sadb_msg_seq = 0;
 	hdr->sadb_msg_pid = 0;
 
+	/* Addresses to be used by KM for negotiation, if ext is available */
+	if (k != NULL && (set_sadb_kmaddress(skb, k) < 0))
+		return -EINVAL;
+
 	/* selector src */
 	set_sadb_address(skb, sasize_sel, SADB_EXT_ADDRESS_SRC, sel);
 
@@ -3449,7 +3500,8 @@ err:
 }
 #else
 static int pfkey_send_migrate(struct xfrm_selector *sel, u8 dir, u8 type,
-			      struct xfrm_migrate *m, int num_bundles)
+			      struct xfrm_migrate *m, int num_bundles,
+			      struct xfrm_kmaddress *k)
 {
 	return -ENOPROTOOPT;
 }

net/xfrm/xfrm_policy.c

@@ -2679,7 +2679,8 @@ static int xfrm_migrate_check(struct xfrm_migrate *m, int num_migrate)
 }
 
 int xfrm_migrate(struct xfrm_selector *sel, u8 dir, u8 type,
-		 struct xfrm_migrate *m, int num_migrate)
+		 struct xfrm_migrate *m, int num_migrate,
+		 struct xfrm_kmaddress *k)
 {
 	int i, err, nx_cur = 0, nx_new = 0;
 	struct xfrm_policy *pol = NULL;
@@ -2723,7 +2724,7 @@ int xfrm_migrate(struct xfrm_selector *sel, u8 dir, u8 type,
 	}
 
 	/* Stage 5 - announce */
-	km_migrate(sel, dir, type, m, num_migrate);
+	km_migrate(sel, dir, type, m, num_migrate, k);
 
 	xfrm_pol_put(pol);
 

net/xfrm/xfrm_state.c

@@ -1814,7 +1814,8 @@ EXPORT_SYMBOL(km_policy_expired);
 
 #ifdef CONFIG_XFRM_MIGRATE
 int km_migrate(struct xfrm_selector *sel, u8 dir, u8 type,
-	       struct xfrm_migrate *m, int num_migrate)
+	       struct xfrm_migrate *m, int num_migrate,
+	       struct xfrm_kmaddress *k)
 {
 	int err = -EINVAL;
 	int ret;
@@ -1823,7 +1824,7 @@ int km_migrate(struct xfrm_selector *sel, u8 dir, u8 type,
 	read_lock(&xfrm_km_lock);
 	list_for_each_entry(km, &xfrm_km_list, list) {
 		if (km->migrate) {
-			ret = km->migrate(sel, dir, type, m, num_migrate);
+			ret = km->migrate(sel, dir, type, m, num_migrate, k);
 			if (!ret)
 				err = ret;
 		}

net/xfrm/xfrm_user.c

@@ -1710,12 +1710,23 @@ static int xfrm_add_acquire(struct sk_buff *skb, struct nlmsghdr *nlh,
 
 #ifdef CONFIG_XFRM_MIGRATE
 static int copy_from_user_migrate(struct xfrm_migrate *ma,
+				  struct xfrm_kmaddress *k,
 				  struct nlattr **attrs, int *num)
 {
 	struct nlattr *rt = attrs[XFRMA_MIGRATE];
 	struct xfrm_user_migrate *um;
 	int i, num_migrate;
 
+	if (k != NULL) {
+		struct xfrm_user_kmaddress *uk;
+
+		uk = nla_data(attrs[XFRMA_KMADDRESS]);
+		memcpy(&k->local, &uk->local, sizeof(k->local));
+		memcpy(&k->remote, &uk->remote, sizeof(k->remote));
+		k->family = uk->family;
+		k->reserved = uk->reserved;
+	}
+
 	um = nla_data(rt);
 	num_migrate = nla_len(rt) / sizeof(*um);
 
@@ -1745,6 +1756,7 @@ static int xfrm_do_migrate(struct sk_buff *skb, struct nlmsghdr *nlh,
 {
 	struct xfrm_userpolicy_id *pi = nlmsg_data(nlh);
 	struct xfrm_migrate m[XFRM_MAX_DEPTH];
+	struct xfrm_kmaddress km, *kmp;
 	u8 type;
 	int err;
 	int n = 0;
@@ -1752,19 +1764,20 @@ static int xfrm_do_migrate(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (attrs[XFRMA_MIGRATE] == NULL)
 		return -EINVAL;
 
+	kmp = attrs[XFRMA_KMADDRESS] ? &km : NULL;
+
 	err = copy_from_user_policy_type(&type, attrs);
 	if (err)
 		return err;
 
-	err = copy_from_user_migrate((struct xfrm_migrate *)m,
-				     attrs, &n);
+	err = copy_from_user_migrate((struct xfrm_migrate *)m, kmp, attrs, &n);
 	if (err)
 		return err;
 
 	if (!n)
 		return 0;
 
-	xfrm_migrate(&pi->sel, pi->dir, type, m, n);
+	xfrm_migrate(&pi->sel, pi->dir, type, m, n, kmp);
 
 	return 0;
 }
@@ -1795,16 +1808,30 @@ static int copy_to_user_migrate(struct xfrm_migrate *m, struct sk_buff *skb)
 	return nla_put(skb, XFRMA_MIGRATE, sizeof(um), &um);
 }
 
-static inline size_t xfrm_migrate_msgsize(int num_migrate)
+static int copy_to_user_kmaddress(struct xfrm_kmaddress *k, struct sk_buff *skb)
+{
+	struct xfrm_user_kmaddress uk;
+
+	memset(&uk, 0, sizeof(uk));
+	uk.family = k->family;
+	uk.reserved = k->reserved;
+	memcpy(&uk.local, &k->local, sizeof(uk.local));
+	memcpy(&uk.remote, &k->local, sizeof(uk.remote));
+
+	return nla_put(skb, XFRMA_KMADDRESS, sizeof(uk), &uk);
+}
+
+static inline size_t xfrm_migrate_msgsize(int num_migrate, int with_kma)
 {
 	return NLMSG_ALIGN(sizeof(struct xfrm_userpolicy_id))
-	       + nla_total_size(sizeof(struct xfrm_user_migrate) * num_migrate)
-	       + userpolicy_type_attrsize();
+	      + (with_kma ? nla_total_size(sizeof(struct xfrm_kmaddress)) : 0)
+	      + nla_total_size(sizeof(struct xfrm_user_migrate) * num_migrate)
+	      + userpolicy_type_attrsize();
 }
 
 static int build_migrate(struct sk_buff *skb, struct xfrm_migrate *m,
-			 int num_migrate, struct xfrm_selector *sel,
-			 u8 dir, u8 type)
+			 int num_migrate, struct xfrm_kmaddress *k,
+			 struct xfrm_selector *sel, u8 dir, u8 type)
 {
 	struct xfrm_migrate *mp;
 	struct xfrm_userpolicy_id *pol_id;
@@ -1821,6 +1848,9 @@ static int build_migrate(struct sk_buff *skb, struct xfrm_migrate *m,
 	memcpy(&pol_id->sel, sel, sizeof(pol_id->sel));
 	pol_id->dir = dir;
 
+	if (k != NULL && (copy_to_user_kmaddress(k, skb) < 0))
+			goto nlmsg_failure;
+
 	if (copy_to_user_policy_type(type, skb) < 0)
 		goto nlmsg_failure;
 
@@ -1836,23 +1866,25 @@ nlmsg_failure:
 }
 
 static int xfrm_send_migrate(struct xfrm_selector *sel, u8 dir, u8 type,
-			     struct xfrm_migrate *m, int num_migrate)
+			     struct xfrm_migrate *m, int num_migrate,
+			     struct xfrm_kmaddress *k)
 {
 	struct sk_buff *skb;
 
-	skb = nlmsg_new(xfrm_migrate_msgsize(num_migrate), GFP_ATOMIC);
+	skb = nlmsg_new(xfrm_migrate_msgsize(num_migrate, !!k), GFP_ATOMIC);
 	if (skb == NULL)
 		return -ENOMEM;
 
 	/* build migrate */
-	if (build_migrate(skb, m, num_migrate, sel, dir, type) < 0)
+	if (build_migrate(skb, m, num_migrate, k, sel, dir, type) < 0)
 		BUG();
 
 	return nlmsg_multicast(xfrm_nl, skb, 0, XFRMNLGRP_MIGRATE, GFP_ATOMIC);
 }
 #else
 static int xfrm_send_migrate(struct xfrm_selector *sel, u8 dir, u8 type,
-			     struct xfrm_migrate *m, int num_migrate)
+			     struct xfrm_migrate *m, int num_migrate,
+			     struct xfrm_kmaddress *k)
 {
 	return -ENOPROTOOPT;
 }
@@ -1901,6 +1933,7 @@ static const struct nla_policy xfrma_policy[XFRMA_MAX+1] = {
 	[XFRMA_COADDR]		= { .len = sizeof(xfrm_address_t) },
 	[XFRMA_POLICY_TYPE]	= { .len = sizeof(struct xfrm_userpolicy_type)},
 	[XFRMA_MIGRATE]		= { .len = sizeof(struct xfrm_user_migrate) },
+	[XFRMA_KMADDRESS]	= { .len = sizeof(struct xfrm_user_kmaddress) },
 };
 
 static struct xfrm_link {