[PATCH 4.14 07/21] xfrm: clean up xfrm protocol checks

From: Greg Kroah-Hartman
Date: Fri Sep 13 2019 - 09:33:23 EST


From: Cong Wang <xiyou.wangcong@xxxxxxxxx>

commit dbb2483b2a46fbaf833cfb5deb5ed9cace9c7399 upstream.

In commit 6a53b7593233 ("xfrm: check id proto in validate_tmpl()")
I introduced a check for xfrm protocol, but according to Herbert
IPSEC_PROTO_ANY should only be used as a wildcard for lookup, so
it should be removed from validate_tmpl().

And, IPSEC_PROTO_ANY is expected to only match 3 IPSec-specific
protocols, this is why xfrm_state_flush() could still miss
IPPROTO_ROUTING, which leads that those entries are left in
net->xfrm.state_all before exit net. Fix this by replacing
IPSEC_PROTO_ANY with zero.

This patch also extracts the check from validate_tmpl() to
xfrm_id_proto_valid() and uses it in parse_ipsecrequest().
With this, no other protocols should be added into xfrm.

Fixes: 6a53b7593233 ("xfrm: check id proto in validate_tmpl()")
Reported-by: syzbot+0bf0519d6e0de15914fe@xxxxxxxxxxxxxxxxxxxxxxxxx
Cc: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx>
Acked-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: Zubin Mithra <zsm@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
include/net/xfrm.h | 17 +++++++++++++++++
net/key/af_key.c | 4 +++-
net/xfrm/xfrm_state.c | 2 +-
net/xfrm/xfrm_user.c | 14 +-------------
4 files changed, 22 insertions(+), 15 deletions(-)

--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1366,6 +1366,23 @@ static inline int xfrm_state_kern(const
return atomic_read(&x->tunnel_users);
}

+static inline bool xfrm_id_proto_valid(u8 proto)
+{
+ switch (proto) {
+ case IPPROTO_AH:
+ case IPPROTO_ESP:
+ case IPPROTO_COMP:
+#if IS_ENABLED(CONFIG_IPV6)
+ case IPPROTO_ROUTING:
+ case IPPROTO_DSTOPTS:
+#endif
+ return true;
+ default:
+ return false;
+ }
+}
+
+/* IPSEC_PROTO_ANY only matches 3 IPsec protocols, 0 could match all. */
static inline int xfrm_id_proto_match(u8 proto, u8 userproto)
{
return (!userproto || proto == userproto ||
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -1951,8 +1951,10 @@ parse_ipsecrequest(struct xfrm_policy *x

if (rq->sadb_x_ipsecrequest_mode == 0)
return -EINVAL;
+ if (!xfrm_id_proto_valid(rq->sadb_x_ipsecrequest_proto))
+ return -EINVAL;

- t->id.proto = rq->sadb_x_ipsecrequest_proto; /* XXX check proto */
+ t->id.proto = rq->sadb_x_ipsecrequest_proto;
if ((mode = pfkey_mode_to_xfrm(rq->sadb_x_ipsecrequest_mode)) < 0)
return -EINVAL;
t->mode = mode;
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -2330,7 +2330,7 @@ void xfrm_state_fini(struct net *net)
unsigned int sz;

flush_work(&net->xfrm.state_hash_work);
- xfrm_state_flush(net, IPSEC_PROTO_ANY, false);
+ xfrm_state_flush(net, 0, false);
flush_work(&xfrm_state_gc_work);

WARN_ON(!list_empty(&net->xfrm.state_all));
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1489,20 +1489,8 @@ static int validate_tmpl(int nr, struct
return -EINVAL;
}

- switch (ut[i].id.proto) {
- case IPPROTO_AH:
- case IPPROTO_ESP:
- case IPPROTO_COMP:
-#if IS_ENABLED(CONFIG_IPV6)
- case IPPROTO_ROUTING:
- case IPPROTO_DSTOPTS:
-#endif
- case IPSEC_PROTO_ANY:
- break;
- default:
+ if (!xfrm_id_proto_valid(ut[i].id.proto))
return -EINVAL;
- }
-
}

return 0;