[PATCH 4.19 04/57] xfrm: Check if_id in xfrm_migrate

Greg Kroah-Hartman
2022-03-21T14:00:18Z

From: Yan Yan <evitayan@google.com>

[ Upstream commit c1aca3080e382886e2e58e809787441984a2f89b ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/net/xfrm.h | 5 +++--
net/key/af_key.c | 2 +-
net/xfrm/xfrm_policy.c | 14 ++++++++------
net/xfrm/xfrm_state.c | 7 ++++++-
net/xfrm/xfrm_user.c | 6 +++++-
5 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index fe8bed557691..a8aa2bb74ad6 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1763,14 +1763,15 @@ 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 c7d5a6015389..388910cf0978 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -2633,7 +2633,7 @@ 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 e9aea82f370d..ab6d0c6576a6 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -3050,7 +3050,7 @@ 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;
@@ -3059,7 +3059,8 @@ 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;
@@ -3071,7 +3072,8 @@ 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;
@@ -3187,7 +3189,7 @@ 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;
@@ -3206,14 +3208,14 @@ 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 44acc724122b..0fd67d1acbfb 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -1466,7 +1466,8 @@ static struct xfrm_state *xfrm_state_clone(struct xfrm_state *orig,
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;
@@ -1482,6 +1483,8 @@ 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,
@@ -1497,6 +1500,8 @@ 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 87932f6ad9d7..3db5cd70b16a 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -2369,6 +2369,7 @@ 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;
@@ -2393,7 +2394,10 @@ static int xfrm_do_migrate(struct sk_buff *skb, struct nlmsghdr *nlh,
return 0;
}

- 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);

--
2.34.1