pfkey: Use const where possible.

This actually pointed out a (seemingly known) bug where we mangle the
pfkey header in a potentially shared SKB, which is fixed here.

Signed-off-by: David S. Miller <davem@davemloft.net>

net/key/af_key.c

@@ -70,7 +70,7 @@ static inline struct pfkey_sock *pfkey_sk(struct sock *sk)
 	return (struct pfkey_sock *)sk;
 }
 
-static int pfkey_can_dump(struct sock *sk)
+static int pfkey_can_dump(const struct sock *sk)
 {
 	if (3 * atomic_read(&sk->sk_rmem_alloc) <= 2 * sk->sk_rcvbuf)
 		return 1;
@@ -303,12 +303,13 @@ static int pfkey_do_dump(struct pfkey_sock *pfk)
 	return rc;
 }
 
-static inline void pfkey_hdr_dup(struct sadb_msg *new, struct sadb_msg *orig)
+static inline void pfkey_hdr_dup(struct sadb_msg *new,
+				 const struct sadb_msg *orig)
 {
 	*new = *orig;
 }
 
-static int pfkey_error(struct sadb_msg *orig, int err, struct sock *sk)
+static int pfkey_error(const struct sadb_msg *orig, int err, struct sock *sk)
 {
 	struct sk_buff *skb = alloc_skb(sizeof(struct sadb_msg) + 16, GFP_KERNEL);
 	struct sadb_msg *hdr;
@@ -369,13 +370,13 @@ static u8 sadb_ext_min_len[] = {
 };
 
 /* Verify sadb_address_{len,prefixlen} against sa_family.  */
-static int verify_address_len(void *p)
+static int verify_address_len(const void *p)
 {
-	struct sadb_address *sp = p;
-	struct sockaddr *addr = (struct sockaddr *)(sp + 1);
-	struct sockaddr_in *sin;
+	const struct sadb_address *sp = p;
+	const struct sockaddr *addr = (const struct sockaddr *)(sp + 1);
+	const struct sockaddr_in *sin;
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
-	struct sockaddr_in6 *sin6;
+	const struct sockaddr_in6 *sin6;
 #endif
 	int len;
 
@@ -411,16 +412,16 @@ static int verify_address_len(void *p)
 	return 0;
 }
 
-static inline int pfkey_sec_ctx_len(struct sadb_x_sec_ctx *sec_ctx)
+static inline int pfkey_sec_ctx_len(const struct sadb_x_sec_ctx *sec_ctx)
 {
 	return DIV_ROUND_UP(sizeof(struct sadb_x_sec_ctx) +
 			    sec_ctx->sadb_x_ctx_len,
 			    sizeof(uint64_t));
 }
 
-static inline int verify_sec_ctx_len(void *p)
+static inline int verify_sec_ctx_len(const void *p)
 {
-	struct sadb_x_sec_ctx *sec_ctx = (struct sadb_x_sec_ctx *)p;
+	const struct sadb_x_sec_ctx *sec_ctx = p;
 	int len = sec_ctx->sadb_x_ctx_len;
 
 	if (len > PAGE_SIZE)
@@ -434,7 +435,7 @@ static inline int verify_sec_ctx_len(void *p)
 	return 0;
 }
 
-static inline struct xfrm_user_sec_ctx *pfkey_sadb2xfrm_user_sec_ctx(struct sadb_x_sec_ctx *sec_ctx)
+static inline struct xfrm_user_sec_ctx *pfkey_sadb2xfrm_user_sec_ctx(const struct sadb_x_sec_ctx *sec_ctx)
 {
 	struct xfrm_user_sec_ctx *uctx = NULL;
 	int ctx_size = sec_ctx->sadb_x_ctx_len;
@@ -455,16 +456,16 @@ static inline struct xfrm_user_sec_ctx *pfkey_sadb2xfrm_user_sec_ctx(struct sadb
 	return uctx;
 }
 
-static int present_and_same_family(struct sadb_address *src,
-				   struct sadb_address *dst)
+static int present_and_same_family(const struct sadb_address *src,
+				   const struct sadb_address *dst)
 {
-	struct sockaddr *s_addr, *d_addr;
+	const struct sockaddr *s_addr, *d_addr;
 
 	if (!src || !dst)
 		return 0;
 
-	s_addr = (struct sockaddr *)(src + 1);
-	d_addr = (struct sockaddr *)(dst + 1);
+	s_addr = (const struct sockaddr *)(src + 1);
+	d_addr = (const struct sockaddr *)(dst + 1);
 	if (s_addr->sa_family != d_addr->sa_family)
 		return 0;
 	if (s_addr->sa_family != AF_INET
@@ -477,15 +478,15 @@ static int present_and_same_family(struct sadb_address *src,
 	return 1;
 }
 
-static int parse_exthdrs(struct sk_buff *skb, struct sadb_msg *hdr, void **ext_hdrs)
+static int parse_exthdrs(struct sk_buff *skb, const struct sadb_msg *hdr, void **ext_hdrs)
 {
-	char *p = (char *) hdr;
+	const char *p = (char *) hdr;
 	int len = skb->len;
 
 	len -= sizeof(*hdr);
 	p += sizeof(*hdr);
 	while (len > 0) {
-		struct sadb_ext *ehdr = (struct sadb_ext *) p;
+		const struct sadb_ext *ehdr = (const struct sadb_ext *) p;
 		uint16_t ext_type;
 		int ext_len;
 
@@ -514,7 +515,7 @@ static int parse_exthdrs(struct sk_buff *skb, struct sadb_msg *hdr, void **ext_h
 				if (verify_sec_ctx_len(p))
 					return -EINVAL;
 			}
-			ext_hdrs[ext_type-1] = p;
+			ext_hdrs[ext_type-1] = (void *) p;
 		}
 		p   += ext_len;
 		len -= ext_len;
@@ -606,21 +607,21 @@ int pfkey_sockaddr_extract(const struct sockaddr *sa, xfrm_address_t *xaddr)
 }
 
 static
-int pfkey_sadb_addr2xfrm_addr(struct sadb_address *addr, xfrm_address_t *xaddr)
+int pfkey_sadb_addr2xfrm_addr(const struct sadb_address *addr, xfrm_address_t *xaddr)
 {
 	return pfkey_sockaddr_extract((struct sockaddr *)(addr + 1),
 				      xaddr);
 }
 
-static struct  xfrm_state *pfkey_xfrm_state_lookup(struct net *net, struct sadb_msg *hdr, void **ext_hdrs)
+static struct  xfrm_state *pfkey_xfrm_state_lookup(struct net *net, const struct sadb_msg *hdr, void * const *ext_hdrs)
 {
-	struct sadb_sa *sa;
-	struct sadb_address *addr;
+	const struct sadb_sa *sa;
+	const struct sadb_address *addr;
 	uint16_t proto;
 	unsigned short family;
 	xfrm_address_t *xaddr;
 
-	sa = (struct sadb_sa *) ext_hdrs[SADB_EXT_SA-1];
+	sa = (const struct sadb_sa *) ext_hdrs[SADB_EXT_SA-1];
 	if (sa == NULL)
 		return NULL;
 
@@ -629,18 +630,18 @@ static struct  xfrm_state *pfkey_xfrm_state_lookup(struct net *net, struct sadb_
 		return NULL;
 
 	/* sadb_address_len should be checked by caller */
-	addr = (struct sadb_address *) ext_hdrs[SADB_EXT_ADDRESS_DST-1];
+	addr = (const struct sadb_address *) ext_hdrs[SADB_EXT_ADDRESS_DST-1];
 	if (addr == NULL)
 		return NULL;
 
-	family = ((struct sockaddr *)(addr + 1))->sa_family;
+	family = ((const struct sockaddr *)(addr + 1))->sa_family;
 	switch (family) {
 	case AF_INET:
-		xaddr = (xfrm_address_t *)&((struct sockaddr_in *)(addr + 1))->sin_addr;
+		xaddr = (xfrm_address_t *)&((const struct sockaddr_in *)(addr + 1))->sin_addr;
 		break;
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 	case AF_INET6:
-		xaddr = (xfrm_address_t *)&((struct sockaddr_in6 *)(addr + 1))->sin6_addr;
+		xaddr = (xfrm_address_t *)&((const struct sockaddr_in6 *)(addr + 1))->sin6_addr;
 		break;
 #endif
 	default:
@@ -691,8 +692,8 @@ static inline int pfkey_mode_to_xfrm(int mode)
 }
 
 static unsigned int pfkey_sockaddr_fill(const xfrm_address_t *xaddr, __be16 port,
-				       struct sockaddr *sa,
-				       unsigned short family)
+					struct sockaddr *sa,
+					unsigned short family)
 {
 	switch (family) {
 	case AF_INET:
@@ -720,7 +721,7 @@ static unsigned int pfkey_sockaddr_fill(const xfrm_address_t *xaddr, __be16 port
 	return 0;
 }
 
-static struct sk_buff *__pfkey_xfrm_state2msg(struct xfrm_state *x,
+static struct sk_buff *__pfkey_xfrm_state2msg(const struct xfrm_state *x,
 					      int add_keys, int hsc)
 {
 	struct sk_buff *skb;
@@ -1010,7 +1011,7 @@ static struct sk_buff *__pfkey_xfrm_state2msg(struct xfrm_state *x,
 }
 
 
-static inline struct sk_buff *pfkey_xfrm_state2msg(struct xfrm_state *x)
+static inline struct sk_buff *pfkey_xfrm_state2msg(const struct xfrm_state *x)
 {
 	struct sk_buff *skb;
 
@@ -1019,26 +1020,26 @@ static inline struct sk_buff *pfkey_xfrm_state2msg(struct xfrm_state *x)
 	return skb;
 }
 
-static inline struct sk_buff *pfkey_xfrm_state2msg_expire(struct xfrm_state *x,
+static inline struct sk_buff *pfkey_xfrm_state2msg_expire(const struct xfrm_state *x,
 							  int hsc)
 {
 	return __pfkey_xfrm_state2msg(x, 0, hsc);
 }
 
 static struct xfrm_state * pfkey_msg2xfrm_state(struct net *net,
-						struct sadb_msg *hdr,
-						void **ext_hdrs)
+						const struct sadb_msg *hdr,
+						void * const *ext_hdrs)
 {
 	struct xfrm_state *x;
-	struct sadb_lifetime *lifetime;
-	struct sadb_sa *sa;
-	struct sadb_key *key;
-	struct sadb_x_sec_ctx *sec_ctx;
+	const struct sadb_lifetime *lifetime;
+	const struct sadb_sa *sa;
+	const struct sadb_key *key;
+	const struct sadb_x_sec_ctx *sec_ctx;
 	uint16_t proto;
 	int err;
 
 
-	sa = (struct sadb_sa *) ext_hdrs[SADB_EXT_SA-1];
+	sa = (const struct sadb_sa *) ext_hdrs[SADB_EXT_SA-1];
 	if (!sa ||
 	    !present_and_same_family(ext_hdrs[SADB_EXT_ADDRESS_SRC-1],
 				     ext_hdrs[SADB_EXT_ADDRESS_DST-1]))
@@ -1077,7 +1078,7 @@ static struct xfrm_state * pfkey_msg2xfrm_state(struct net *net,
 	     sa->sadb_sa_encrypt > SADB_X_CALG_MAX) ||
 	    sa->sadb_sa_encrypt > SADB_EALG_MAX)
 		return ERR_PTR(-EINVAL);
-	key = (struct sadb_key*) ext_hdrs[SADB_EXT_KEY_AUTH-1];
+	key = (const struct sadb_key*) ext_hdrs[SADB_EXT_KEY_AUTH-1];
 	if (key != NULL &&
 	    sa->sadb_sa_auth != SADB_X_AALG_NULL &&
 	    ((key->sadb_key_bits+7) / 8 == 0 ||
@@ -1104,14 +1105,14 @@ static struct xfrm_state * pfkey_msg2xfrm_state(struct net *net,
 	if (sa->sadb_sa_flags & SADB_SAFLAGS_NOPMTUDISC)
 		x->props.flags |= XFRM_STATE_NOPMTUDISC;
 
-	lifetime = (struct sadb_lifetime*) ext_hdrs[SADB_EXT_LIFETIME_HARD-1];
+	lifetime = (const struct sadb_lifetime*) ext_hdrs[SADB_EXT_LIFETIME_HARD-1];
 	if (lifetime != NULL) {
 		x->lft.hard_packet_limit = _KEY2X(lifetime->sadb_lifetime_allocations);
 		x->lft.hard_byte_limit = _KEY2X(lifetime->sadb_lifetime_bytes);
 		x->lft.hard_add_expires_seconds = lifetime->sadb_lifetime_addtime;
 		x->lft.hard_use_expires_seconds = lifetime->sadb_lifetime_usetime;
 	}
-	lifetime = (struct sadb_lifetime*) ext_hdrs[SADB_EXT_LIFETIME_SOFT-1];
+	lifetime = (const struct sadb_lifetime*) ext_hdrs[SADB_EXT_LIFETIME_SOFT-1];
 	if (lifetime != NULL) {
 		x->lft.soft_packet_limit = _KEY2X(lifetime->sadb_lifetime_allocations);
 		x->lft.soft_byte_limit = _KEY2X(lifetime->sadb_lifetime_bytes);
@@ -1119,7 +1120,7 @@ static struct xfrm_state * pfkey_msg2xfrm_state(struct net *net,
 		x->lft.soft_use_expires_seconds = lifetime->sadb_lifetime_usetime;
 	}
 
-	sec_ctx = (struct sadb_x_sec_ctx *) ext_hdrs[SADB_X_EXT_SEC_CTX-1];
+	sec_ctx = (const struct sadb_x_sec_ctx *) ext_hdrs[SADB_X_EXT_SEC_CTX-1];
 	if (sec_ctx != NULL) {
 		struct xfrm_user_sec_ctx *uctx = pfkey_sadb2xfrm_user_sec_ctx(sec_ctx);
 
@@ -1133,7 +1134,7 @@ static struct xfrm_state * pfkey_msg2xfrm_state(struct net *net,
 			goto out;
 	}
 
-	key = (struct sadb_key*) ext_hdrs[SADB_EXT_KEY_AUTH-1];
+	key = (const struct sadb_key*) ext_hdrs[SADB_EXT_KEY_AUTH-1];
 	if (sa->sadb_sa_auth) {
 		int keysize = 0;
 		struct xfrm_algo_desc *a = xfrm_aalg_get_byid(sa->sadb_sa_auth);
@@ -1202,7 +1203,7 @@ static struct xfrm_state * pfkey_msg2xfrm_state(struct net *net,
 				  &x->id.daddr);
 
 	if (ext_hdrs[SADB_X_EXT_SA2-1]) {
-		struct sadb_x_sa2 *sa2 = (void*)ext_hdrs[SADB_X_EXT_SA2-1];
+		const struct sadb_x_sa2 *sa2 = ext_hdrs[SADB_X_EXT_SA2-1];
 		int mode = pfkey_mode_to_xfrm(sa2->sadb_x_sa2_mode);
 		if (mode < 0) {
 			err = -EINVAL;
@@ -1213,7 +1214,7 @@ static struct xfrm_state * pfkey_msg2xfrm_state(struct net *net,
 	}
 
 	if (ext_hdrs[SADB_EXT_ADDRESS_PROXY-1]) {
-		struct sadb_address *addr = ext_hdrs[SADB_EXT_ADDRESS_PROXY-1];
+		const struct sadb_address *addr = ext_hdrs[SADB_EXT_ADDRESS_PROXY-1];
 
 		/* Nobody uses this, but we try. */
 		x->sel.family = pfkey_sadb_addr2xfrm_addr(addr, &x->sel.saddr);
@@ -1224,7 +1225,7 @@ static struct xfrm_state * pfkey_msg2xfrm_state(struct net *net,
 		x->sel.family = x->props.family;
 
 	if (ext_hdrs[SADB_X_EXT_NAT_T_TYPE-1]) {
-		struct sadb_x_nat_t_type* n_type;
+		const struct sadb_x_nat_t_type* n_type;
 		struct xfrm_encap_tmpl *natt;
 
 		x->encap = kmalloc(sizeof(*x->encap), GFP_KERNEL);
@@ -1236,12 +1237,12 @@ static struct xfrm_state * pfkey_msg2xfrm_state(struct net *net,
 		natt->encap_type = n_type->sadb_x_nat_t_type_type;
 
 		if (ext_hdrs[SADB_X_EXT_NAT_T_SPORT-1]) {
-			struct sadb_x_nat_t_port* n_port =
+			const struct sadb_x_nat_t_port *n_port =
 				ext_hdrs[SADB_X_EXT_NAT_T_SPORT-1];
 			natt->encap_sport = n_port->sadb_x_nat_t_port_port;
 		}
 		if (ext_hdrs[SADB_X_EXT_NAT_T_DPORT-1]) {
-			struct sadb_x_nat_t_port* n_port =
+			const struct sadb_x_nat_t_port *n_port =
 				ext_hdrs[SADB_X_EXT_NAT_T_DPORT-1];
 			natt->encap_dport = n_port->sadb_x_nat_t_port_port;
 		}
@@ -1261,12 +1262,12 @@ out:
 	return ERR_PTR(err);
 }
 
-static int pfkey_reserved(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr, void **ext_hdrs)
+static int pfkey_reserved(struct sock *sk, struct sk_buff *skb, const struct sadb_msg *hdr, void * const *ext_hdrs)
 {
 	return -EOPNOTSUPP;
 }
 
-static int pfkey_getspi(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr, void **ext_hdrs)
+static int pfkey_getspi(struct sock *sk, struct sk_buff *skb, const struct sadb_msg *hdr, void * const *ext_hdrs)
 {
 	struct net *net = sock_net(sk);
 	struct sk_buff *resp_skb;
@@ -1365,7 +1366,7 @@ static int pfkey_getspi(struct sock *sk, struct sk_buff *skb, struct sadb_msg *h
 	return 0;
 }
 
-static int pfkey_acquire(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr, void **ext_hdrs)
+static int pfkey_acquire(struct sock *sk, struct sk_buff *skb, const struct sadb_msg *hdr, void * const *ext_hdrs)
 {
 	struct net *net = sock_net(sk);
 	struct xfrm_state *x;
@@ -1453,7 +1454,7 @@ static int key_notify_sa(struct xfrm_state *x, const struct km_event *c)
 	return 0;
 }
 
-static int pfkey_add(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr, void **ext_hdrs)
+static int pfkey_add(struct sock *sk, struct sk_buff *skb, const struct sadb_msg *hdr, void * const *ext_hdrs)
 {
 	struct net *net = sock_net(sk);
 	struct xfrm_state *x;
@@ -1492,7 +1493,7 @@ out:
 	return err;
 }
 
-static int pfkey_delete(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr, void **ext_hdrs)
+static int pfkey_delete(struct sock *sk, struct sk_buff *skb, const struct sadb_msg *hdr, void * const *ext_hdrs)
 {
 	struct net *net = sock_net(sk);
 	struct xfrm_state *x;
@@ -1534,7 +1535,7 @@ out:
 	return err;
 }
 
-static int pfkey_get(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr, void **ext_hdrs)
+static int pfkey_get(struct sock *sk, struct sk_buff *skb, const struct sadb_msg *hdr, void * const *ext_hdrs)
 {
 	struct net *net = sock_net(sk);
 	__u8 proto;
@@ -1570,7 +1571,7 @@ static int pfkey_get(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr,
 	return 0;
 }
 
-static struct sk_buff *compose_sadb_supported(struct sadb_msg *orig,
+static struct sk_buff *compose_sadb_supported(const struct sadb_msg *orig,
 					      gfp_t allocation)
 {
 	struct sk_buff *skb;
@@ -1642,7 +1643,7 @@ out_put_algs:
 	return skb;
 }
 
-static int pfkey_register(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr, void **ext_hdrs)
+static int pfkey_register(struct sock *sk, struct sk_buff *skb, const struct sadb_msg *hdr, void * const *ext_hdrs)
 {
 	struct pfkey_sock *pfk = pfkey_sk(sk);
 	struct sk_buff *supp_skb;
@@ -1671,7 +1672,7 @@ static int pfkey_register(struct sock *sk, struct sk_buff *skb, struct sadb_msg
 	return 0;
 }
 
-static int unicast_flush_resp(struct sock *sk, struct sadb_msg *ihdr)
+static int unicast_flush_resp(struct sock *sk, const struct sadb_msg *ihdr)
 {
 	struct sk_buff *skb;
 	struct sadb_msg *hdr;
@@ -1710,7 +1711,7 @@ static int key_notify_sa_flush(const struct km_event *c)
 	return 0;
 }
 
-static int pfkey_flush(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr, void **ext_hdrs)
+static int pfkey_flush(struct sock *sk, struct sk_buff *skb, const struct sadb_msg *hdr, void * const *ext_hdrs)
 {
 	struct net *net = sock_net(sk);
 	unsigned proto;
@@ -1784,7 +1785,7 @@ static void pfkey_dump_sa_done(struct pfkey_sock *pfk)
 	xfrm_state_walk_done(&pfk->dump.u.state);
 }
 
-static int pfkey_dump(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr, void **ext_hdrs)
+static int pfkey_dump(struct sock *sk, struct sk_buff *skb, const struct sadb_msg *hdr, void * const *ext_hdrs)
 {
 	u8 proto;
 	struct pfkey_sock *pfk = pfkey_sk(sk);
@@ -1805,19 +1806,29 @@ static int pfkey_dump(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr
 	return pfkey_do_dump(pfk);
 }
 
-static int pfkey_promisc(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr, void **ext_hdrs)
+static int pfkey_promisc(struct sock *sk, struct sk_buff *skb, const struct sadb_msg *hdr, void * const *ext_hdrs)
 {
 	struct pfkey_sock *pfk = pfkey_sk(sk);
 	int satype = hdr->sadb_msg_satype;
+	bool reset_errno = false;
 
 	if (hdr->sadb_msg_len == (sizeof(*hdr) / sizeof(uint64_t))) {
-		/* XXX we mangle packet... */
-		hdr->sadb_msg_errno = 0;
+		reset_errno = true;
 		if (satype != 0 && satype != 1)
 			return -EINVAL;
 		pfk->promisc = satype;
 	}
-	pfkey_broadcast(skb_clone(skb, GFP_KERNEL), GFP_KERNEL, BROADCAST_ALL, NULL, sock_net(sk));
+	if (reset_errno && skb_cloned(skb))
+		skb = skb_copy(skb, GFP_KERNEL);
+	else
+		skb = skb_clone(skb, GFP_KERNEL);
+
+	if (reset_errno && skb) {
+		struct sadb_msg *new_hdr = (struct sadb_msg *) skb->data;
+		new_hdr->sadb_msg_errno = 0;
+	}
+
+	pfkey_broadcast(skb, GFP_KERNEL, BROADCAST_ALL, NULL, sock_net(sk));
 	return 0;
 }
 
@@ -1921,7 +1932,7 @@ parse_ipsecrequests(struct xfrm_policy *xp, struct sadb_x_policy *pol)
 	return 0;
 }
 
-static inline int pfkey_xfrm_policy2sec_ctx_size(struct xfrm_policy *xp)
+static inline int pfkey_xfrm_policy2sec_ctx_size(const struct xfrm_policy *xp)
 {
   struct xfrm_sec_ctx *xfrm_ctx = xp->security;
 
@@ -1933,9 +1944,9 @@ static inline int pfkey_xfrm_policy2sec_ctx_size(struct xfrm_policy *xp)
 	return 0;
 }
 
-static int pfkey_xfrm_policy2msg_size(struct xfrm_policy *xp)
+static int pfkey_xfrm_policy2msg_size(const struct xfrm_policy *xp)
 {
-	struct xfrm_tmpl *t;
+	const struct xfrm_tmpl *t;
 	int sockaddr_size = pfkey_sockaddr_size(xp->family);
 	int socklen = 0;
 	int i;
@@ -1955,7 +1966,7 @@ static int pfkey_xfrm_policy2msg_size(struct xfrm_policy *xp)
 		pfkey_xfrm_policy2sec_ctx_size(xp);
 }
 
-static struct sk_buff * pfkey_xfrm_policy2msg_prep(struct xfrm_policy *xp)
+static struct sk_buff * pfkey_xfrm_policy2msg_prep(const struct xfrm_policy *xp)
 {
 	struct sk_buff *skb;
 	int size;
@@ -1969,7 +1980,7 @@ static struct sk_buff * pfkey_xfrm_policy2msg_prep(struct xfrm_policy *xp)
 	return skb;
 }
 
-static int pfkey_xfrm_policy2msg(struct sk_buff *skb, struct xfrm_policy *xp, int dir)
+static int pfkey_xfrm_policy2msg(struct sk_buff *skb, const struct xfrm_policy *xp, int dir)
 {
 	struct sadb_msg *hdr;
 	struct sadb_address *addr;
@@ -2065,8 +2076,8 @@ static int pfkey_xfrm_policy2msg(struct sk_buff *skb, struct xfrm_policy *xp, in
 	pol->sadb_x_policy_priority = xp->priority;
 
 	for (i=0; i<xp->xfrm_nr; i++) {
+		const struct xfrm_tmpl *t = xp->xfrm_vec + i;
 		struct sadb_x_ipsecrequest *rq;
-		struct xfrm_tmpl *t = xp->xfrm_vec + i;
 		int req_size;
 		int mode;
 
@@ -2152,7 +2163,7 @@ static int key_notify_policy(struct xfrm_policy *xp, int dir, const struct km_ev
 
 }
 
-static int pfkey_spdadd(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr, void **ext_hdrs)
+static int pfkey_spdadd(struct sock *sk, struct sk_buff *skb, const struct sadb_msg *hdr, void * const *ext_hdrs)
 {
 	struct net *net = sock_net(sk);
 	int err = 0;
@@ -2273,7 +2284,7 @@ out:
 	return err;
 }
 
-static int pfkey_spddelete(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr, void **ext_hdrs)
+static int pfkey_spddelete(struct sock *sk, struct sk_buff *skb, const struct sadb_msg *hdr, void * const *ext_hdrs)
 {
 	struct net *net = sock_net(sk);
 	int err;
@@ -2350,7 +2361,7 @@ out:
 	return err;
 }
 
-static int key_pol_get_resp(struct sock *sk, struct xfrm_policy *xp, struct sadb_msg *hdr, int dir)
+static int key_pol_get_resp(struct sock *sk, struct xfrm_policy *xp, const struct sadb_msg *hdr, int dir)
 {
 	int err;
 	struct sk_buff *out_skb;
@@ -2458,7 +2469,7 @@ static int ipsecrequests_to_migrate(struct sadb_x_ipsecrequest *rq1, int len,
 }
 
 static int pfkey_migrate(struct sock *sk, struct sk_buff *skb,
-			 struct sadb_msg *hdr, void **ext_hdrs)
+			 const struct sadb_msg *hdr, void * const *ext_hdrs)
 {
 	int i, len, ret, err = -EINVAL;
 	u8 dir;
@@ -2556,7 +2567,7 @@ static int pfkey_migrate(struct sock *sk, struct sk_buff *skb,
 #endif
 
 
-static int pfkey_spdget(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr, void **ext_hdrs)
+static int pfkey_spdget(struct sock *sk, struct sk_buff *skb, const struct sadb_msg *hdr, void * const *ext_hdrs)
 {
 	struct net *net = sock_net(sk);
 	unsigned int dir;
@@ -2644,7 +2655,7 @@ static void pfkey_dump_sp_done(struct pfkey_sock *pfk)
 	xfrm_policy_walk_done(&pfk->dump.u.policy);
 }
 
-static int pfkey_spddump(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr, void **ext_hdrs)
+static int pfkey_spddump(struct sock *sk, struct sk_buff *skb, const struct sadb_msg *hdr, void * const *ext_hdrs)
 {
 	struct pfkey_sock *pfk = pfkey_sk(sk);
 
@@ -2680,7 +2691,7 @@ static int key_notify_policy_flush(const struct km_event *c)
 
 }
 
-static int pfkey_spdflush(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr, void **ext_hdrs)
+static int pfkey_spdflush(struct sock *sk, struct sk_buff *skb, const struct sadb_msg *hdr, void * const *ext_hdrs)
 {
 	struct net *net = sock_net(sk);
 	struct km_event c;
@@ -2709,7 +2720,7 @@ static int pfkey_spdflush(struct sock *sk, struct sk_buff *skb, struct sadb_msg
 }
 
 typedef int (*pfkey_handler)(struct sock *sk, struct sk_buff *skb,
-			     struct sadb_msg *hdr, void **ext_hdrs);
+			     const struct sadb_msg *hdr, void * const *ext_hdrs);
 static pfkey_handler pfkey_funcs[SADB_MAX + 1] = {
 	[SADB_RESERVED]		= pfkey_reserved,
 	[SADB_GETSPI]		= pfkey_getspi,
@@ -2736,7 +2747,7 @@ static pfkey_handler pfkey_funcs[SADB_MAX + 1] = {
 	[SADB_X_MIGRATE]	= pfkey_migrate,
 };
 
-static int pfkey_process(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hdr)
+static int pfkey_process(struct sock *sk, struct sk_buff *skb, const struct sadb_msg *hdr)
 {
 	void *ext_hdrs[SADB_EXT_MAX];
 	int err;
@@ -2781,7 +2792,8 @@ static struct sadb_msg *pfkey_get_base_msg(struct sk_buff *skb, int *errp)
 	return hdr;
 }
 
-static inline int aalg_tmpl_set(struct xfrm_tmpl *t, struct xfrm_algo_desc *d)
+static inline int aalg_tmpl_set(const struct xfrm_tmpl *t,
+				const struct xfrm_algo_desc *d)
 {
 	unsigned int id = d->desc.sadb_alg_id;
 
@@ -2791,7 +2803,8 @@ static inline int aalg_tmpl_set(struct xfrm_tmpl *t, struct xfrm_algo_desc *d)
 	return (t->aalgos >> id) & 1;
 }
 
-static inline int ealg_tmpl_set(struct xfrm_tmpl *t, struct xfrm_algo_desc *d)
+static inline int ealg_tmpl_set(const struct xfrm_tmpl *t,
+				const struct xfrm_algo_desc *d)
 {
 	unsigned int id = d->desc.sadb_alg_id;
 
@@ -2801,12 +2814,12 @@ static inline int ealg_tmpl_set(struct xfrm_tmpl *t, struct xfrm_algo_desc *d)
 	return (t->ealgos >> id) & 1;
 }
 
-static int count_ah_combs(struct xfrm_tmpl *t)
+static int count_ah_combs(const struct xfrm_tmpl *t)
 {
 	int i, sz = 0;
 
 	for (i = 0; ; i++) {
-		struct xfrm_algo_desc *aalg = xfrm_aalg_get_byidx(i);
+		const struct xfrm_algo_desc *aalg = xfrm_aalg_get_byidx(i);
 		if (!aalg)
 			break;
 		if (aalg_tmpl_set(t, aalg) && aalg->available)
@@ -2815,12 +2828,12 @@ static int count_ah_combs(struct xfrm_tmpl *t)
 	return sz + sizeof(struct sadb_prop);
 }
 
-static int count_esp_combs(struct xfrm_tmpl *t)
+static int count_esp_combs(const struct xfrm_tmpl *t)
 {
 	int i, k, sz = 0;
 
 	for (i = 0; ; i++) {
-		struct xfrm_algo_desc *ealg = xfrm_ealg_get_byidx(i);
+		const struct xfrm_algo_desc *ealg = xfrm_ealg_get_byidx(i);
 		if (!ealg)
 			break;
 
@@ -2828,7 +2841,7 @@ static int count_esp_combs(struct xfrm_tmpl *t)
 			continue;
 
 		for (k = 1; ; k++) {
-			struct xfrm_algo_desc *aalg = xfrm_aalg_get_byidx(k);
+			const struct xfrm_algo_desc *aalg = xfrm_aalg_get_byidx(k);
 			if (!aalg)
 				break;
 
@@ -2839,7 +2852,7 @@ static int count_esp_combs(struct xfrm_tmpl *t)
 	return sz + sizeof(struct sadb_prop);
 }
 
-static void dump_ah_combs(struct sk_buff *skb, struct xfrm_tmpl *t)
+static void dump_ah_combs(struct sk_buff *skb, const struct xfrm_tmpl *t)
 {
 	struct sadb_prop *p;
 	int i;
@@ -2851,7 +2864,7 @@ static void dump_ah_combs(struct sk_buff *skb, struct xfrm_tmpl *t)
 	memset(p->sadb_prop_reserved, 0, sizeof(p->sadb_prop_reserved));
 
 	for (i = 0; ; i++) {
-		struct xfrm_algo_desc *aalg = xfrm_aalg_get_byidx(i);
+		const struct xfrm_algo_desc *aalg = xfrm_aalg_get_byidx(i);
 		if (!aalg)
 			break;
 
@@ -2871,7 +2884,7 @@ static void dump_ah_combs(struct sk_buff *skb, struct xfrm_tmpl *t)
 	}
 }
 
-static void dump_esp_combs(struct sk_buff *skb, struct xfrm_tmpl *t)
+static void dump_esp_combs(struct sk_buff *skb, const struct xfrm_tmpl *t)
 {
 	struct sadb_prop *p;
 	int i, k;
@@ -2883,7 +2896,7 @@ static void dump_esp_combs(struct sk_buff *skb, struct xfrm_tmpl *t)
 	memset(p->sadb_prop_reserved, 0, sizeof(p->sadb_prop_reserved));
 
 	for (i=0; ; i++) {
-		struct xfrm_algo_desc *ealg = xfrm_ealg_get_byidx(i);
+		const struct xfrm_algo_desc *ealg = xfrm_ealg_get_byidx(i);
 		if (!ealg)
 			break;
 
@@ -2892,7 +2905,7 @@ static void dump_esp_combs(struct sk_buff *skb, struct xfrm_tmpl *t)
 
 		for (k = 1; ; k++) {
 			struct sadb_comb *c;
-			struct xfrm_algo_desc *aalg = xfrm_aalg_get_byidx(k);
+			const struct xfrm_algo_desc *aalg = xfrm_aalg_get_byidx(k);
 			if (!aalg)
 				break;
 			if (!(aalg_tmpl_set(t, aalg) && aalg->available))