xfrm: Check if_id in xfrm_migrate

This patch enables distinguishing SAs and SPs based on if_id during
the xfrm_migrate flow. This ensures support for xfrm interfaces
throughout the SA/SP lifecycle.

When there are multiple existing SPs with the same direction,
the same xfrm_selector and different endpoint addresses,
xfrm_migrate might fail with ENODATA.

Specifically, the code path for performing xfrm_migrate is:
  Stage 1: find policy to migrate with
    xfrm_migrate_policy_find(sel, dir, type, net)
  Stage 2: find and update state(s) with
    xfrm_migrate_state_find(mp, net)
  Stage 3: update endpoint address(es) of template(s) with
    xfrm_policy_migrate(pol, m, num_migrate)

Currently "Stage 1" always returns the first xfrm_policy that
matches, and "Stage 3" looks for the xfrm_tmpl that matches the
old endpoint address. Thus if there are multiple xfrm_policy
with same selector, direction, type and net, "Stage 1" might
rertun a wrong xfrm_policy and "Stage 3" will fail with ENODATA
because it cannot find a xfrm_tmpl with the matching endpoint
address.

The fix is to allow userspace to pass an if_id and add if_id
to the matching rule in Stage 1 and Stage 2 since if_id is a
unique ID for xfrm_policy and xfrm_state. For compatibility,
if_id will only be checked if the attribute is set.

Tested with additions to Android's kernel unit test suite:
https://android-review.googlesource.com/c/kernel/tests/+/1668886

Signed-off-by: Yan Yan <evitayan@google.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index fdb41e8..743dd1d 100644 (file)
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1681,14 +1681,15 @@ int km_migrate(const struct xfrm_selector *sel, u8 dir, u8 type,
               const struct xfrm_migrate *m, int num_bundles,
               const struct xfrm_kmaddress *k,
               const struct xfrm_encap_tmpl *encap);
-struct xfrm_state *xfrm_migrate_state_find(struct xfrm_migrate *m, struct net *net);
+struct xfrm_state *xfrm_migrate_state_find(struct xfrm_migrate *m, struct net *net,
+                                               u32 if_id);
 struct xfrm_state *xfrm_state_migrate(struct xfrm_state *x,
                                      struct xfrm_migrate *m,
                                      struct xfrm_encap_tmpl *encap);
 int xfrm_migrate(const struct xfrm_selector *sel, u8 dir, u8 type,
                 struct xfrm_migrate *m, int num_bundles,
                 struct xfrm_kmaddress *k, struct net *net,
-                struct xfrm_encap_tmpl *encap);
+                struct xfrm_encap_tmpl *encap, u32 if_id);
 #endif
 
 int km_new_mapping(struct xfrm_state *x, xfrm_address_t *ipaddr, __be16 sport);

diff --git a/net/key/af_key.c b/net/key/af_key.c
index de24a7d..9bf52a0 100644 (file)
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -2623,7 +2623,7 @@ static int pfkey_migrate(struct sock *sk, struct sk_buff *skb,
        }
 
        return xfrm_migrate(&sel, dir, XFRM_POLICY_TYPE_MAIN, m, i,
-                           kma ? &k : NULL, net, NULL);
+                           kma ? &k : NULL, net, NULL, 0);
 
  out:
        return err;

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 04d1ce9..8825261 100644 (file)
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -4256,7 +4256,7 @@ static bool xfrm_migrate_selector_match(const struct xfrm_selector *sel_cmp,
 }
 
 static struct xfrm_policy *xfrm_migrate_policy_find(const struct xfrm_selector *sel,
-                                                   u8 dir, u8 type, struct net *net)
+                                                   u8 dir, u8 type, struct net *net, u32 if_id)
 {
        struct xfrm_policy *pol, *ret = NULL;
        struct hlist_head *chain;
@@ -4265,7 +4265,8 @@ static struct xfrm_policy *xfrm_migrate_policy_find(const struct xfrm_selector *
        spin_lock_bh(&net->xfrm.xfrm_policy_lock);
        chain = policy_hash_direct(net, &sel->daddr, &sel->saddr, sel->family, dir);
        hlist_for_each_entry(pol, chain, bydst) {
-               if (xfrm_migrate_selector_match(sel, &pol->selector) &&
+               if ((if_id == 0 || pol->if_id == if_id) &&
+                   xfrm_migrate_selector_match(sel, &pol->selector) &&
                    pol->type == type) {
                        ret = pol;
                        priority = ret->priority;
@@ -4277,7 +4278,8 @@ static struct xfrm_policy *xfrm_migrate_policy_find(const struct xfrm_selector *
                if ((pol->priority >= priority) && ret)
                        break;
 
-               if (xfrm_migrate_selector_match(sel, &pol->selector) &&
+               if ((if_id == 0 || pol->if_id == if_id) &&
+                   xfrm_migrate_selector_match(sel, &pol->selector) &&
                    pol->type == type) {
                        ret = pol;
                        break;
@@ -4393,7 +4395,7 @@ static int xfrm_migrate_check(const struct xfrm_migrate *m, int num_migrate)
 int xfrm_migrate(const struct xfrm_selector *sel, u8 dir, u8 type,
                 struct xfrm_migrate *m, int num_migrate,
                 struct xfrm_kmaddress *k, struct net *net,
-                struct xfrm_encap_tmpl *encap)
+                struct xfrm_encap_tmpl *encap, u32 if_id)
 {
        int i, err, nx_cur = 0, nx_new = 0;
        struct xfrm_policy *pol = NULL;
@@ -4412,14 +4414,14 @@ int xfrm_migrate(const struct xfrm_selector *sel, u8 dir, u8 type,
        }
 
        /* Stage 1 - find policy */
-       if ((pol = xfrm_migrate_policy_find(sel, dir, type, net)) == NULL) {
+       if ((pol = xfrm_migrate_policy_find(sel, dir, type, net, if_id)) == NULL) {
                err = -ENOENT;
                goto out;
        }
 
        /* Stage 2 - find and update state(s) */
        for (i = 0, mp = m; i < num_migrate; i++, mp++) {
-               if ((x = xfrm_migrate_state_find(mp, net))) {
+               if ((x = xfrm_migrate_state_find(mp, net, if_id))) {
                        x_cur[nx_cur] = x;
                        nx_cur++;
                        xc = xfrm_state_migrate(x, mp, encap);

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index ca6bee1..b0eeb0a 100644 (file)
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -1606,7 +1606,8 @@ out:
        return NULL;
 }
 
-struct xfrm_state *xfrm_migrate_state_find(struct xfrm_migrate *m, struct net *net)
+struct xfrm_state *xfrm_migrate_state_find(struct xfrm_migrate *m, struct net *net,
+                                               u32 if_id)
 {
        unsigned int h;
        struct xfrm_state *x = NULL;
@@ -1622,6 +1623,8 @@ struct xfrm_state *xfrm_migrate_state_find(struct xfrm_migrate *m, struct net *n
                                continue;
                        if (m->reqid && x->props.reqid != m->reqid)
                                continue;
+                       if (if_id != 0 && x->if_id != if_id)
+                               continue;
                        if (!xfrm_addr_equal(&x->id.daddr, &m->old_daddr,
                                             m->old_family) ||
                            !xfrm_addr_equal(&x->props.saddr, &m->old_saddr,
@@ -1637,6 +1640,8 @@ struct xfrm_state *xfrm_migrate_state_find(struct xfrm_migrate *m, struct net *n
                        if (x->props.mode != m->mode ||
                            x->id.proto != m->proto)
                                continue;
+                       if (if_id != 0 && x->if_id != if_id)
+                               continue;
                        if (!xfrm_addr_equal(&x->id.daddr, &m->old_daddr,
                                             m->old_family) ||
                            !xfrm_addr_equal(&x->props.saddr, &m->old_saddr,

diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 8cd6c81..a4fb596 100644 (file)
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -2608,6 +2608,7 @@ static int xfrm_do_migrate(struct sk_buff *skb, struct nlmsghdr *nlh,
        int n = 0;
        struct net *net = sock_net(skb->sk);
        struct xfrm_encap_tmpl  *encap = NULL;
+       u32 if_id = 0;
 
        if (attrs[XFRMA_MIGRATE] == NULL)
                return -EINVAL;
@@ -2632,7 +2633,10 @@ static int xfrm_do_migrate(struct sk_buff *skb, struct nlmsghdr *nlh,
                        return -ENOMEM;
        }
 
-       err = xfrm_migrate(&pi->sel, pi->dir, type, m, n, kmp, net, encap);
+       if (attrs[XFRMA_IF_ID])
+               if_id = nla_get_u32(attrs[XFRMA_IF_ID]);
+
+       err = xfrm_migrate(&pi->sel, pi->dir, type, m, n, kmp, net, encap, if_id);
 
        kfree(encap);