[IPv6] route: Convert GETROUTE to use new netlink api

Fixes various unvalidated netlink attributes causing memory
corruptions when left empty by userspace applications.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 44 insertions, 36 deletions

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index f0a66de84331..5d6e9083ca2c 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1833,6 +1833,7 @@ void rt6_mtu_change(struct net_device *dev, unsigned mtu)
 static struct nla_policy rtm_ipv6_policy[RTA_MAX+1] __read_mostly = {
         [RTA_GATEWAY]           = { .minlen = sizeof(struct in6_addr) },
         [RTA_OIF]               = { .type = NLA_U32 },
+        [RTA_IIF]               = { .type = NLA_U32 },
         [RTA_PRIORITY]          = { .type = NLA_U32 },
         [RTA_METRICS]           = { .type = NLA_NESTED },
 };
@@ -2048,68 +2049,75 @@ int rt6_dump_route(struct rt6_info *rt, void *p_arg)
 
 int inet6_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void *arg)
 {
-        struct rtattr **rta = arg;
-        int iif = 0;
-        int err = -ENOBUFS;
+        struct nlattr *tb[RTA_MAX+1];
+        struct rt6_info *rt;
         struct sk_buff *skb;
+        struct rtmsg *rtm;
         struct flowi fl;
-        struct rt6_info *rt;
-
-        skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
-        if (skb == NULL)
-                goto out;
+        int err, iif = 0;
 
-        /* Reserve room for dummy headers, this skb can pass
-           through good chunk of routing engine.
-         */
-        skb->mac.raw = skb->data;
-        skb_reserve(skb, MAX_HEADER + sizeof(struct ipv6hdr));
+        err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv6_policy);
+        if (err < 0)
+                goto errout;
 
+        err = -EINVAL;
         memset(&fl, 0, sizeof(fl));
-        if (rta[RTA_SRC-1])
-                ipv6_addr_copy(&fl.fl6_src,
-                               (struct in6_addr*)RTA_DATA(rta[RTA_SRC-1]));
-        if (rta[RTA_DST-1])
-                ipv6_addr_copy(&fl.fl6_dst,
-                               (struct in6_addr*)RTA_DATA(rta[RTA_DST-1]));
 
-        if (rta[RTA_IIF-1])
-                memcpy(&iif, RTA_DATA(rta[RTA_IIF-1]), sizeof(int));
+        if (tb[RTA_SRC]) {
+                if (nla_len(tb[RTA_SRC]) < sizeof(struct in6_addr))
+                        goto errout;
+
+                ipv6_addr_copy(&fl.fl6_src, nla_data(tb[RTA_SRC]));
+        }
+
+        if (tb[RTA_DST]) {
+                if (nla_len(tb[RTA_DST]) < sizeof(struct in6_addr))
+                        goto errout;
+
+                ipv6_addr_copy(&fl.fl6_dst, nla_data(tb[RTA_DST]));
+        }
+
+        if (tb[RTA_IIF])
+                iif = nla_get_u32(tb[RTA_IIF]);
+
+        if (tb[RTA_OIF])
+                fl.oif = nla_get_u32(tb[RTA_OIF]);
 
         if (iif) {
                 struct net_device *dev;
                 dev = __dev_get_by_index(iif);
                 if (!dev) {
                         err = -ENODEV;
-                        goto out_free;
+                        goto errout;
                 }
         }
 
-        fl.oif = 0;
-        if (rta[RTA_OIF-1])
-                memcpy(&fl.oif, RTA_DATA(rta[RTA_OIF-1]), sizeof(int));
+        skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
+        if (skb == NULL) {
+                err = -ENOBUFS;
+                goto errout;
+        }
 
-        rt = (struct rt6_info*)ip6_route_output(NULL, &fl);
+        /* Reserve room for dummy headers, this skb can pass
+           through good chunk of routing engine.
+         */
+        skb->mac.raw = skb->data;
+        skb_reserve(skb, MAX_HEADER + sizeof(struct ipv6hdr));
 
+        rt = (struct rt6_info*) ip6_route_output(NULL, &fl);
         skb->dst = &rt->u.dst;
 
-        NETLINK_CB(skb).dst_pid = NETLINK_CB(in_skb).pid;
-        err = rt6_fill_node(skb, rt, 
-                            &fl.fl6_dst, &fl.fl6_src,
-                            iif,
+        err = rt6_fill_node(skb, rt, &fl.fl6_dst, &fl.fl6_src, iif,
                             RTM_NEWROUTE, NETLINK_CB(in_skb).pid,
                             nlh->nlmsg_seq, 0, 0);
         if (err < 0) {
-                err = -EMSGSIZE;
-                goto out_free;
+                kfree_skb(skb);
+                goto errout;
         }
 
         err = rtnl_unicast(skb, NETLINK_CB(in_skb).pid);
-out:
+errout:
         return err;
-out_free:
-        kfree_skb(skb);
-        goto out;       
 }
 
 void inet6_rt_notify(int event, struct rt6_info *rt, struct nl_info *info)