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, 27 insertions, 18 deletions

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 5208b12fbfb4..eb96ce52f178 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -656,15 +656,23 @@ void xfrm_sad_getinfo(struct net *net, struct xfrmk_sadinfo *si)
 EXPORT_SYMBOL(xfrm_sad_getinfo);
 
 static int
-xfrm_init_tempsel(struct xfrm_state *x, struct flowi *fl,
-                  struct xfrm_tmpl *tmpl,
-                  xfrm_address_t *daddr, xfrm_address_t *saddr,
-                  unsigned short family)
+xfrm_init_tempstate(struct xfrm_state *x, struct flowi *fl,
+                    struct xfrm_tmpl *tmpl,
+                    xfrm_address_t *daddr, xfrm_address_t *saddr,
+                    unsigned short family)
 {
         struct xfrm_state_afinfo *afinfo = xfrm_state_get_afinfo(family);
         if (!afinfo)
                 return -1;
-        afinfo->init_tempsel(x, fl, tmpl, daddr, saddr);
+        afinfo->init_tempsel(&x->sel, fl);
+
+        if (family != tmpl->encap_family) {
+                xfrm_state_put_afinfo(afinfo);
+                afinfo = xfrm_state_get_afinfo(tmpl->encap_family);
+                if (!afinfo)
+                        return -1;
+        }
+        afinfo->init_temprop(x, tmpl, daddr, saddr);
         xfrm_state_put_afinfo(afinfo);
         return 0;
 }
@@ -790,37 +798,38 @@ xfrm_state_find(xfrm_address_t *daddr, xfrm_address_t *saddr,
         int error = 0;
         struct xfrm_state *best = NULL;
         u32 mark = pol->mark.v & pol->mark.m;
+        unsigned short encap_family = tmpl->encap_family;
 
         to_put = NULL;
 
         spin_lock_bh(&xfrm_state_lock);
-        h = xfrm_dst_hash(net, daddr, saddr, tmpl->reqid, family);
+        h = xfrm_dst_hash(net, daddr, saddr, tmpl->reqid, encap_family);
         hlist_for_each_entry(x, entry, net->xfrm.state_bydst+h, bydst) {
-                if (x->props.family == family &&
+                if (x->props.family == encap_family &&
                     x->props.reqid == tmpl->reqid &&
                     (mark & x->mark.m) == x->mark.v &&
                     !(x->props.flags & XFRM_STATE_WILDRECV) &&
-                    xfrm_state_addr_check(x, daddr, saddr, family) &&
+                    xfrm_state_addr_check(x, daddr, saddr, encap_family) &&
                     tmpl->mode == x->props.mode &&
                     tmpl->id.proto == x->id.proto &&
                     (tmpl->id.spi == x->id.spi || !tmpl->id.spi))
-                        xfrm_state_look_at(pol, x, fl, family, daddr, saddr,
+                        xfrm_state_look_at(pol, x, fl, encap_family, daddr, saddr,
                                            &best, &acquire_in_progress, &error);
         }
         if (best)
                 goto found;
 
-        h_wildcard = xfrm_dst_hash(net, daddr, &saddr_wildcard, tmpl->reqid, family);
+        h_wildcard = xfrm_dst_hash(net, daddr, &saddr_wildcard, tmpl->reqid, encap_family);
         hlist_for_each_entry(x, entry, net->xfrm.state_bydst+h_wildcard, bydst) {
-                if (x->props.family == family &&
+                if (x->props.family == encap_family &&
                     x->props.reqid == tmpl->reqid &&
                     (mark & x->mark.m) == x->mark.v &&
                     !(x->props.flags & XFRM_STATE_WILDRECV) &&
-                    xfrm_state_addr_check(x, daddr, saddr, family) &&
+                    xfrm_state_addr_check(x, daddr, saddr, encap_family) &&
                     tmpl->mode == x->props.mode &&
                     tmpl->id.proto == x->id.proto &&
                     (tmpl->id.spi == x->id.spi || !tmpl->id.spi))
-                        xfrm_state_look_at(pol, x, fl, family, daddr, saddr,
+                        xfrm_state_look_at(pol, x, fl, encap_family, daddr, saddr,
                                            &best, &acquire_in_progress, &error);
         }
 
@@ -829,7 +838,7 @@ found:
         if (!x && !error && !acquire_in_progress) {
                 if (tmpl->id.spi &&
                     (x0 = __xfrm_state_lookup(net, mark, daddr, tmpl->id.spi,
-                                              tmpl->id.proto, family)) != NULL) {
+                                              tmpl->id.proto, encap_family)) != NULL) {
                         to_put = x0;
                         error = -EEXIST;
                         goto out;
@@ -839,9 +848,9 @@ found:
                         error = -ENOMEM;
                         goto out;
                 }
-                /* Initialize temporary selector matching only
+                /* Initialize temporary state matching only
                  * to current session. */
-                xfrm_init_tempsel(x, fl, tmpl, daddr, saddr, family);
+                xfrm_init_tempstate(x, fl, tmpl, daddr, saddr, family);
                 memcpy(&x->mark, &pol->mark, sizeof(x->mark));
 
                 error = security_xfrm_state_alloc_acquire(x, pol->security, fl->secid);
@@ -856,10 +865,10 @@ found:
                         x->km.state = XFRM_STATE_ACQ;
                         list_add(&x->km.all, &net->xfrm.state_all);
                         hlist_add_head(&x->bydst, net->xfrm.state_bydst+h);
-                        h = xfrm_src_hash(net, daddr, saddr, family);
+                        h = xfrm_src_hash(net, daddr, saddr, encap_family);
                         hlist_add_head(&x->bysrc, net->xfrm.state_bysrc+h);
                         if (x->id.spi) {
-                                h = xfrm_spi_hash(net, &x->id.daddr, x->id.spi, x->id.proto, family);
+                                h = xfrm_spi_hash(net, &x->id.daddr, x->id.spi, x->id.proto, encap_family);
                                 hlist_add_head(&x->byspi, net->xfrm.state_byspi+h);
                         }
                         x->lft.hard_add_expires_seconds = net->xfrm.sysctl_acq_expires;