[IPv4]: Convert route get to 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>

diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index 42ed96f..fcc159a 100644 (file)
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -216,6 +216,7 @@ extern void fib_select_default(const struct flowi *flp, struct fib_result *res);
 #endif /* CONFIG_IP_MULTIPLE_TABLES */
 
 /* Exported by fib_frontend.c */
+extern struct nla_policy rtm_ipv4_policy[];
 extern void            ip_fib_init(void);
 extern int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg);
 extern int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg);

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index d537c93..d0abeab 100644 (file)
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -453,7 +453,7 @@ int ip_rt_ioctl(unsigned int cmd, void *arg)
 
 #endif
 
-static struct nla_policy rtm_ipv4_policy[RTA_MAX+1] __read_mostly = {
+struct nla_policy rtm_ipv4_policy[RTA_MAX+1] __read_mostly = {
        [RTA_DST]               = { .type = NLA_U32 },
        [RTA_SRC]               = { .type = NLA_U32 },
        [RTA_IIF]               = { .type = NLA_U32 },

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 31b6705..a4d4cb8 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2737,18 +2737,24 @@ nla_put_failure:
 
 int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void *arg)
 {
-       struct rtattr **rta = arg;
-       struct rtmsg *rtm = NLMSG_DATA(nlh);
+       struct rtmsg *rtm;
+       struct nlattr *tb[RTA_MAX+1];
        struct rtable *rt = NULL;
-       u32 dst = 0;
-       u32 src = 0;
-       int iif = 0;
-       int err = -ENOBUFS;
+       u32 dst, src, iif;
+       int err;
        struct sk_buff *skb;
 
+       err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
+       if (err < 0)
+               goto errout;
+
+       rtm = nlmsg_data(nlh);
+
        skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
-       if (!skb)
-               goto out;
+       if (skb == NULL) {
+               err = -ENOBUFS;
+               goto errout;
+       }
 
        /* Reserve room for dummy headers, this skb can pass
           through good chunk of routing engine.
@@ -2759,61 +2765,61 @@ int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void *arg)
        skb->nh.iph->protocol = IPPROTO_ICMP;
        skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
 
-       if (rta[RTA_SRC - 1])
-               memcpy(&src, RTA_DATA(rta[RTA_SRC - 1]), 4);
-       if (rta[RTA_DST - 1])
-               memcpy(&dst, RTA_DATA(rta[RTA_DST - 1]), 4);
-       if (rta[RTA_IIF - 1])
-               memcpy(&iif, RTA_DATA(rta[RTA_IIF - 1]), sizeof(int));
+       src = tb[RTA_SRC] ? nla_get_u32(tb[RTA_SRC]) : 0;
+       dst = tb[RTA_DST] ? nla_get_u32(tb[RTA_DST]) : 0;
+       iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
 
        if (iif) {
-               struct net_device *dev = __dev_get_by_index(iif);
-               err = -ENODEV;
-               if (!dev)
-                       goto out_free;
+               struct net_device *dev;
+
+               dev = __dev_get_by_index(iif);
+               if (dev == NULL) {
+                       err = -ENODEV;
+                       goto errout_free;
+               }
+
                skb->protocol   = htons(ETH_P_IP);
                skb->dev        = dev;
                local_bh_disable();
                err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
                local_bh_enable();
-               rt = (struct rtable*)skb->dst;
-               if (!err && rt->u.dst.error)
+
+               rt = (struct rtable*) skb->dst;
+               if (err == 0 && rt->u.dst.error)
                        err = -rt->u.dst.error;
        } else {
-               struct flowi fl = { .nl_u = { .ip4_u = { .daddr = dst,
-                                                        .saddr = src,
-                                                        .tos = rtm->rtm_tos } } };
-               int oif = 0;
-               if (rta[RTA_OIF - 1])
-                       memcpy(&oif, RTA_DATA(rta[RTA_OIF - 1]), sizeof(int));
-               fl.oif = oif;
+               struct flowi fl = {
+                       .nl_u = {
+                               .ip4_u = {
+                                       .daddr = dst,
+                                       .saddr = src,
+                                       .tos = rtm->rtm_tos,
+                               },
+                       },
+                       .oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0,
+               };
                err = ip_route_output_key(&rt, &fl);
        }
+
        if (err)
-               goto out_free;
+               goto errout_free;
 
        skb->dst = &rt->u.dst;
        if (rtm->rtm_flags & RTM_F_NOTIFY)
                rt->rt_flags |= RTCF_NOTIFY;
 
-       NETLINK_CB(skb).dst_pid = NETLINK_CB(in_skb).pid;
-
        err = rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
                                RTM_NEWROUTE, 0, 0);
-       if (!err)
-               goto out_free;
-       if (err < 0) {
-               err = -EMSGSIZE;
-               goto out_free;
-       }
+       if (err <= 0)
+               goto errout_free;
 
        err = rtnl_unicast(skb, NETLINK_CB(in_skb).pid);
-out:
+errout:
        return err;
 
-out_free:
+errout_free:
        kfree_skb(skb);
-       goto out;
+       goto errout;
 }
 
 int ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb)