xfrm: Allow different selector family in temporary state

The family parameter xfrm_state_find is used to find a state matching a
certain policy. This value is set to the template's family
(encap_family) right before xfrm_state_find is called.
The family parameter is however also used to construct a temporary state
in xfrm_state_find itself which is wrong for inter-family scenarios
because it produces a selector for the wrong family. Since this selector
is included in the xfrm_user_acquire structure, user space programs
misinterpret IPv6 addresses as IPv4 and vice versa.
This patch splits up the original init_tempsel function into a part that
initializes the selector respectively the props and id of the temporary
state, to allow for differing ip address families whithin the state.

Signed-off-by: Thomas Egerer <thomas.egerer@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 3 deletions

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 2b3ed7ad4933..cbab6e1a8c9c 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1175,9 +1175,8 @@ xfrm_tmpl_resolve_one(struct xfrm_policy *policy, struct flowi *fl,
                     tmpl->mode == XFRM_MODE_BEET) {
                         remote = &tmpl->id.daddr;
                         local = &tmpl->saddr;
-                        family = tmpl->encap_family;
-                        if (xfrm_addr_any(local, family)) {
-                                error = xfrm_get_saddr(net, &tmp, remote, family);
+                        if (xfrm_addr_any(local, tmpl->encap_family)) {
+                                error = xfrm_get_saddr(net, &tmp, remote, tmpl->encap_family);
                                 if (error)
                                         goto fail;
                                 local = &tmp;