ipv4: Validate route entry type at insert instead of every lookup.

fib_semantic_match() requires that if the type doesn't signal an
automatic error, it must be of type RTN_UNICAST, RTN_LOCAL,
RTN_BROADCAST, RTN_ANYCAST, or RTN_MULTICAST.

Checking this every route lookup is pointless work.

Instead validate it during route insertion, via fib_create_info().

Also, there was nothing making sure the type value was less than
RTN_MAX, so add that missing check while we're here.

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

1 files changed, 28 insertions, 26 deletions

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 562f34cd9303..c29291b21009 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -707,6 +707,9 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
         int nhs = 1;
         struct net *net = cfg->fc_nlinfo.nl_net;
 
+        if (cfg->fc_type > RTN_MAX)
+                goto err_inval;
+
         /* Fast check to catch the most weird cases */
         if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
                 goto err_inval;
@@ -812,6 +815,17 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
                 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
                         goto err_inval;
                 goto link_it;
+        } else {
+                switch (cfg->fc_type) {
+                case RTN_UNICAST:
+                case RTN_LOCAL:
+                case RTN_BROADCAST:
+                case RTN_ANYCAST:
+                case RTN_MULTICAST:
+                        break;
+                default:
+                        goto err_inval;
+                }
         }
 
         if (cfg->fc_scope > RT_SCOPE_HOST)
@@ -915,35 +929,23 @@ int fib_semantic_match(struct fib_table *tb, struct list_head *head,
                         if (fi->fib_flags & RTNH_F_DEAD)
                                 continue;
 
-                        switch (fa->fa_type) {
-                        case RTN_UNICAST:
-                        case RTN_LOCAL:
-                        case RTN_BROADCAST:
-                        case RTN_ANYCAST:
-                        case RTN_MULTICAST:
-                                for_nexthops(fi) {
-                                        if (nh->nh_flags & RTNH_F_DEAD)
-                                                continue;
-                                        if (!flp->oif || flp->oif == nh->nh_oif)
-                                                break;
-                                }
+                        for_nexthops(fi) {
+                                if (nh->nh_flags & RTNH_F_DEAD)
+                                        continue;
+                                if (!flp->oif || flp->oif == nh->nh_oif)
+                                        break;
+                        }
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
-                                if (nhsel < fi->fib_nhs) {
-                                        nh_sel = nhsel;
-                                        goto out_fill_res;
-                                }
+                        if (nhsel < fi->fib_nhs) {
+                                nh_sel = nhsel;
+                                goto out_fill_res;
+                        }
 #else
-                                if (nhsel < 1)
-                                        goto out_fill_res;
+                        if (nhsel < 1)
+                                goto out_fill_res;
 #endif
-                                endfor_nexthops(fi);
-                                continue;
-
-                        default:
-                                pr_warning("fib_semantic_match bad type %#x\n",
-                                           fa->fa_type);
-                                return -EINVAL;
-                        }
+                        endfor_nexthops(fi);
+                        continue;
                 }
                 return err;
         }