xfrm: Add user interface for esn and big anti-replay windows

This patch adds a netlink based user interface to configure
esn and big anti-replay windows. The new netlink attribute
XFRMA_REPLAY_ESN_VAL is used to configure the new implementation.
If the XFRM_STATE_ESN flag is set, we use esn and support for big
anti-replay windows for the configured state. If this flag is not
set we use the new implementation with 32 bit sequence numbers.
A big anti-replay window can be configured in this case anyway.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 85 insertions, 14 deletions

diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index f7b3c857c989..706385ae3e4b 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -119,6 +119,19 @@ static inline int verify_sec_ctx_len(struct nlattr **attrs)
         return 0;
 }
 
+static inline int verify_replay(struct xfrm_usersa_info *p,
+                                struct nlattr **attrs)
+{
+        struct nlattr *rt = attrs[XFRMA_REPLAY_ESN_VAL];
+
+        if (!rt)
+                return 0;
+
+        if (p->replay_window != 0)
+                return -EINVAL;
+
+        return 0;
+}
 
 static int verify_newsa_info(struct xfrm_usersa_info *p,
                              struct nlattr **attrs)
@@ -214,6 +227,8 @@ static int verify_newsa_info(struct xfrm_usersa_info *p,
                 goto out;
         if ((err = verify_sec_ctx_len(attrs)))
                 goto out;
+        if ((err = verify_replay(p, attrs)))
+                goto out;
 
         err = -EINVAL;
         switch (p->mode) {
@@ -345,6 +360,33 @@ static int attach_aead(struct xfrm_algo_aead **algpp, u8 *props,
         return 0;
 }
 
+static int xfrm_alloc_replay_state_esn(struct xfrm_replay_state_esn **replay_esn,
+                                       struct xfrm_replay_state_esn **preplay_esn,
+                                       struct nlattr *rta)
+{
+        struct xfrm_replay_state_esn *p, *pp, *up;
+
+        if (!rta)
+                return 0;
+
+        up = nla_data(rta);
+
+        p = kmemdup(up, xfrm_replay_state_esn_len(up), GFP_KERNEL);
+        if (!p)
+                return -ENOMEM;
+
+        pp = kmemdup(up, xfrm_replay_state_esn_len(up), GFP_KERNEL);
+        if (!pp) {
+                kfree(p);
+                return -ENOMEM;
+        }
+
+        *replay_esn = p;
+        *preplay_esn = pp;
+
+        return 0;
+}
+
 static inline int xfrm_user_sec_ctx_size(struct xfrm_sec_ctx *xfrm_ctx)
 {
         int len = 0;
@@ -380,10 +422,20 @@ static void copy_from_user_state(struct xfrm_state *x, struct xfrm_usersa_info *
 static void xfrm_update_ae_params(struct xfrm_state *x, struct nlattr **attrs)
 {
         struct nlattr *rp = attrs[XFRMA_REPLAY_VAL];
+        struct nlattr *re = attrs[XFRMA_REPLAY_ESN_VAL];
         struct nlattr *lt = attrs[XFRMA_LTIME_VAL];
         struct nlattr *et = attrs[XFRMA_ETIMER_THRESH];
         struct nlattr *rt = attrs[XFRMA_REPLAY_THRESH];
 
+        if (re) {
+                struct xfrm_replay_state_esn *replay_esn;
+                replay_esn = nla_data(re);
+                memcpy(x->replay_esn, replay_esn,
+                       xfrm_replay_state_esn_len(replay_esn));
+                memcpy(x->preplay_esn, replay_esn,
+                       xfrm_replay_state_esn_len(replay_esn));
+        }
+
         if (rp) {
                 struct xfrm_replay_state *replay;
                 replay = nla_data(rp);
@@ -467,13 +519,14 @@ static struct xfrm_state *xfrm_state_construct(struct net *net,
             security_xfrm_state_alloc(x, nla_data(attrs[XFRMA_SEC_CTX])))
                 goto error;
 
+        if ((err = xfrm_alloc_replay_state_esn(&x->replay_esn, &x->preplay_esn,
+                                               attrs[XFRMA_REPLAY_ESN_VAL])))
+                goto error;
+
         x->km.seq = p->seq;
         x->replay_maxdiff = net->xfrm.sysctl_aevent_rseqth;
         /* sysctl_xfrm_aevent_etime is in 100ms units */
         x->replay_maxage = (net->xfrm.sysctl_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;
 
         if ((err = xfrm_init_replay(x)))
                 goto error;
@@ -709,6 +762,10 @@ static int copy_to_user_state_extra(struct xfrm_state *x,
         if (xfrm_mark_put(skb, &x->mark))
                 goto nla_put_failure;
 
+        if (x->replay_esn)
+                NLA_PUT(skb, XFRMA_REPLAY_ESN_VAL,
+                        xfrm_replay_state_esn_len(x->replay_esn), x->replay_esn);
+
         if (x->security && copy_sec_ctx(x->security, skb) < 0)
                 goto nla_put_failure;
 
@@ -1578,10 +1635,14 @@ static int xfrm_flush_sa(struct sk_buff *skb, struct nlmsghdr *nlh,
         return 0;
 }
 
-static inline size_t xfrm_aevent_msgsize(void)
+static inline size_t xfrm_aevent_msgsize(struct xfrm_state *x)
 {
+        size_t replay_size = x->replay_esn ?
+                              xfrm_replay_state_esn_len(x->replay_esn) :
+                              sizeof(struct xfrm_replay_state);
+
         return NLMSG_ALIGN(sizeof(struct xfrm_aevent_id))
-               + nla_total_size(sizeof(struct xfrm_replay_state))
+               + nla_total_size(replay_size)
                + nla_total_size(sizeof(struct xfrm_lifetime_cur))
                + nla_total_size(sizeof(struct xfrm_mark))
                + nla_total_size(4) /* XFRM_AE_RTHR */
@@ -1606,7 +1667,13 @@ static int build_aevent(struct sk_buff *skb, struct xfrm_state *x, const struct
         id->reqid = x->props.reqid;
         id->flags = c->data.aevent;
 
-        NLA_PUT(skb, XFRMA_REPLAY_VAL, sizeof(x->replay), &x->replay);
+        if (x->replay_esn)
+                NLA_PUT(skb, XFRMA_REPLAY_ESN_VAL,
+                        xfrm_replay_state_esn_len(x->replay_esn),
+                        x->replay_esn);
+        else
+                NLA_PUT(skb, XFRMA_REPLAY_VAL, sizeof(x->replay), &x->replay);
+
         NLA_PUT(skb, XFRMA_LTIME_VAL, sizeof(x->curlft), &x->curlft);
 
         if (id->flags & XFRM_AE_RTHR)
@@ -1639,16 +1706,16 @@ static int xfrm_get_ae(struct sk_buff *skb, struct nlmsghdr *nlh,
         struct xfrm_aevent_id *p = nlmsg_data(nlh);
         struct xfrm_usersa_id *id = &p->sa_id;
 
-        r_skb = nlmsg_new(xfrm_aevent_msgsize(), GFP_ATOMIC);
-        if (r_skb == NULL)
-                return -ENOMEM;
-
         mark = xfrm_mark_get(attrs, &m);
 
         x = xfrm_state_lookup(net, mark, &id->daddr, id->spi, id->proto, id->family);
-        if (x == NULL) {
-                kfree_skb(r_skb);
+        if (x == NULL)
                 return -ESRCH;
+
+        r_skb = nlmsg_new(xfrm_aevent_msgsize(x), GFP_ATOMIC);
+        if (r_skb == NULL) {
+                xfrm_state_put(x);
+                return -ENOMEM;
         }
 
         /*
@@ -1680,9 +1747,10 @@ static int xfrm_new_ae(struct sk_buff *skb, struct nlmsghdr *nlh,
         struct xfrm_mark m;
         struct xfrm_aevent_id *p = nlmsg_data(nlh);
         struct nlattr *rp = attrs[XFRMA_REPLAY_VAL];
+        struct nlattr *re = attrs[XFRMA_REPLAY_ESN_VAL];
         struct nlattr *lt = attrs[XFRMA_LTIME_VAL];
 
-        if (!lt && !rp)
+        if (!lt && !rp && !re)
                 return err;
 
         /* pedantic mode - thou shalt sayeth replaceth */
@@ -2147,6 +2215,7 @@ static const struct nla_policy xfrma_policy[XFRMA_MAX+1] = {
         [XFRMA_KMADDRESS]       = { .len = sizeof(struct xfrm_user_kmaddress) },
         [XFRMA_MARK]            = { .len = sizeof(struct xfrm_mark) },
         [XFRMA_TFCPAD]          = { .type = NLA_U32 },
+        [XFRMA_REPLAY_ESN_VAL]  = { .len = sizeof(struct xfrm_replay_state_esn) },
 };
 
 static struct xfrm_link {
@@ -2274,7 +2343,7 @@ static int xfrm_aevent_state_notify(struct xfrm_state *x, const struct km_event
         struct net *net = xs_net(x);
         struct sk_buff *skb;
 
-        skb = nlmsg_new(xfrm_aevent_msgsize(), GFP_ATOMIC);
+        skb = nlmsg_new(xfrm_aevent_msgsize(x), GFP_ATOMIC);
         if (skb == NULL)
                 return -ENOMEM;
 
@@ -2328,6 +2397,8 @@ static inline size_t xfrm_sa_len(struct xfrm_state *x)
                 l += nla_total_size(sizeof(*x->encap));
         if (x->tfcpad)
                 l += nla_total_size(sizeof(x->tfcpad));
+        if (x->replay_esn)
+                l += nla_total_size(xfrm_replay_state_esn_len(x->replay_esn));
         if (x->security)
                 l += nla_total_size(sizeof(struct xfrm_user_sec_ctx) +
                                     x->security->ctx_len);