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>

4 files changed, 67 insertions, 49 deletions

diff --git a/net/ipv4/xfrm4_state.c b/net/ipv4/xfrm4_state.c
index 1ef1366a0a03..47947624eccc 100644
--- a/net/ipv4/xfrm4_state.c
+++ b/net/ipv4/xfrm4_state.c
@@ -21,21 +21,25 @@ static int xfrm4_init_flags(struct xfrm_state *x)
 }
 
 static void
-__xfrm4_init_tempsel(struct xfrm_state *x, struct flowi *fl,
-                     struct xfrm_tmpl *tmpl,
-                     xfrm_address_t *daddr, xfrm_address_t *saddr)
+__xfrm4_init_tempsel(struct xfrm_selector *sel, struct flowi *fl)
+{
+        sel->daddr.a4 = fl->fl4_dst;
+        sel->saddr.a4 = fl->fl4_src;
+        sel->dport = xfrm_flowi_dport(fl);
+        sel->dport_mask = htons(0xffff);
+        sel->sport = xfrm_flowi_sport(fl);
+        sel->sport_mask = htons(0xffff);
+        sel->family = AF_INET;
+        sel->prefixlen_d = 32;
+        sel->prefixlen_s = 32;
+        sel->proto = fl->proto;
+        sel->ifindex = fl->oif;
+}
+
+static void
+xfrm4_init_temprop(struct xfrm_state *x, struct xfrm_tmpl *tmpl,
+                   xfrm_address_t *daddr, xfrm_address_t *saddr)
 {
-        x->sel.daddr.a4 = fl->fl4_dst;
-        x->sel.saddr.a4 = fl->fl4_src;
-        x->sel.dport = xfrm_flowi_dport(fl);
-        x->sel.dport_mask = htons(0xffff);
-        x->sel.sport = xfrm_flowi_sport(fl);
-        x->sel.sport_mask = htons(0xffff);
-        x->sel.family = AF_INET;
-        x->sel.prefixlen_d = 32;
-        x->sel.prefixlen_s = 32;
-        x->sel.proto = fl->proto;
-        x->sel.ifindex = fl->oif;
         x->id = tmpl->id;
         if (x->id.daddr.a4 == 0)
                 x->id.daddr.a4 = daddr->a4;
@@ -70,6 +74,7 @@ static struct xfrm_state_afinfo xfrm4_state_afinfo = {
         .owner                  = THIS_MODULE,
         .init_flags             = xfrm4_init_flags,
         .init_tempsel           = __xfrm4_init_tempsel,
+        .init_temprop           = xfrm4_init_temprop,
         .output                 = xfrm4_output,
         .extract_input          = xfrm4_extract_input,
         .extract_output         = xfrm4_extract_output,
diff --git a/net/ipv6/xfrm6_state.c b/net/ipv6/xfrm6_state.c
index f417b77fa0e1..a67575d472a3 100644
--- a/net/ipv6/xfrm6_state.c
+++ b/net/ipv6/xfrm6_state.c
@@ -20,23 +20,27 @@
 #include <net/addrconf.h>
 
 static void
-__xfrm6_init_tempsel(struct xfrm_state *x, struct flowi *fl,
-                     struct xfrm_tmpl *tmpl,
-                     xfrm_address_t *daddr, xfrm_address_t *saddr)
+__xfrm6_init_tempsel(struct xfrm_selector *sel, struct flowi *fl)
 {
         /* Initialize temporary selector matching only
          * to current session. */
-        ipv6_addr_copy((struct in6_addr *)&x->sel.daddr, &fl->fl6_dst);
-        ipv6_addr_copy((struct in6_addr *)&x->sel.saddr, &fl->fl6_src);
-        x->sel.dport = xfrm_flowi_dport(fl);
-        x->sel.dport_mask = htons(0xffff);
-        x->sel.sport = xfrm_flowi_sport(fl);
-        x->sel.sport_mask = htons(0xffff);
-        x->sel.family = AF_INET6;
-        x->sel.prefixlen_d = 128;
-        x->sel.prefixlen_s = 128;
-        x->sel.proto = fl->proto;
-        x->sel.ifindex = fl->oif;
+        ipv6_addr_copy((struct in6_addr *)&sel->daddr, &fl->fl6_dst);
+        ipv6_addr_copy((struct in6_addr *)&sel->saddr, &fl->fl6_src);
+        sel->dport = xfrm_flowi_dport(fl);
+        sel->dport_mask = htons(0xffff);
+        sel->sport = xfrm_flowi_sport(fl);
+        sel->sport_mask = htons(0xffff);
+        sel->family = AF_INET6;
+        sel->prefixlen_d = 128;
+        sel->prefixlen_s = 128;
+        sel->proto = fl->proto;
+        sel->ifindex = fl->oif;
+}
+
+static void
+xfrm6_init_temprop(struct xfrm_state *x, struct xfrm_tmpl *tmpl,
+                   xfrm_address_t *daddr, xfrm_address_t *saddr)
+{
         x->id = tmpl->id;
         if (ipv6_addr_any((struct in6_addr*)&x->id.daddr))
                 memcpy(&x->id.daddr, daddr, sizeof(x->sel.daddr));
@@ -168,6 +172,7 @@ static struct xfrm_state_afinfo xfrm6_state_afinfo = {
         .eth_proto              = htons(ETH_P_IPV6),
         .owner                  = THIS_MODULE,
         .init_tempsel           = __xfrm6_init_tempsel,
+        .init_temprop           = xfrm6_init_temprop,
         .tmpl_sort              = __xfrm6_tmpl_sort,
         .state_sort             = __xfrm6_state_sort,
         .output                 = xfrm6_output,
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;
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;