[XFRM] xfrm_user: Better validation of user templates.

Since we never checked the ->family value of templates
before, many applications simply leave it at zero.
Detect this and fix it up to be the pol->family value.

Also, do not clobber xp->family while reading in templates,
that is not necessary.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 42 insertions, 8 deletions

diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 6f97665983d..311205ffa77 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -858,7 +858,6 @@ static void copy_templates(struct xfrm_policy *xp, struct xfrm_user_tmpl *ut,
         int i;
 
         xp->xfrm_nr = nr;
-        xp->family = ut->family;
         for (i = 0; i < nr; i++, ut++) {
                 struct xfrm_tmpl *t = &xp->xfrm_vec[i];
 
@@ -876,19 +875,53 @@ static void copy_templates(struct xfrm_policy *xp, struct xfrm_user_tmpl *ut,
         }
 }
 
+static int validate_tmpl(int nr, struct xfrm_user_tmpl *ut, u16 family)
+{
+        int i;
+
+        if (nr > XFRM_MAX_DEPTH)
+                return -EINVAL;
+
+        for (i = 0; i < nr; i++) {
+                /* We never validated the ut->family value, so many
+                 * applications simply leave it at zero.  The check was
+                 * never made and ut->family was ignored because all
+                 * templates could be assumed to have the same family as
+                 * the policy itself.  Now that we will have ipv4-in-ipv6
+                 * and ipv6-in-ipv4 tunnels, this is no longer true.
+                 */
+                if (!ut[i].family)
+                        ut[i].family = family;
+
+                switch (ut[i].family) {
+                case AF_INET:
+                        break;
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+                case AF_INET6:
+                        break;
+#endif
+                default:
+                        return -EINVAL;
+                };
+        }
+
+        return 0;
+}
+
 static int copy_from_user_tmpl(struct xfrm_policy *pol, struct rtattr **xfrma)
 {
         struct rtattr *rt = xfrma[XFRMA_TMPL-1];
-        struct xfrm_user_tmpl *utmpl;
-        int nr;
 
         if (!rt) {
                 pol->xfrm_nr = 0;
         } else {
-                nr = (rt->rta_len - sizeof(*rt)) / sizeof(*utmpl);
+                struct xfrm_user_tmpl *utmpl = RTA_DATA(rt);
+                int nr = (rt->rta_len - sizeof(*rt)) / sizeof(*utmpl);
+                int err;
 
-                if (nr > XFRM_MAX_DEPTH)
-                        return -EINVAL;
+                err = validate_tmpl(nr, utmpl, pol->family);
+                if (err)
+                        return err;
 
                 copy_templates(pol, RTA_DATA(rt), nr);
         }
@@ -1530,7 +1563,8 @@ static int xfrm_add_acquire(struct sk_buff *skb, struct nlmsghdr *nlh, void **xf
         }
 
         /*   build an XP */
-        xp = xfrm_policy_construct(&ua->policy, (struct rtattr **) xfrma, &err);        if (!xp) {
+        xp = xfrm_policy_construct(&ua->policy, (struct rtattr **) xfrma, &err);
+        if (!xp) {
                 kfree(x);
                 return err;
         }
@@ -1979,7 +2013,7 @@ static struct xfrm_policy *xfrm_compile_policy(struct sock *sk, int opt,
                 return NULL;
 
         nr = ((len - sizeof(*p)) / sizeof(*ut));
-        if (nr > XFRM_MAX_DEPTH)
+        if (validate_tmpl(nr, ut, p->sel.family))
                 return NULL;
 
         if (p->dir > XFRM_POLICY_OUT)