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xfrm: Check if_id in xfrm_migrate

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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>
This commit is contained in:
Yan Yan 2022-01-18 16:00:13 -08:00 committed by Steffen Klassert
parent 6596a02295
commit c1aca3080e
5 changed files with 23 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
include/net/xfrm.h
View File

@ -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);

2
net/key/af_key.c
View File

@ -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;

14
net/xfrm/xfrm_policy.c
View File

@ -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);

7
net/xfrm/xfrm_state.c
View File

@ -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,

6
net/xfrm/xfrm_user.c
View File

@ -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);