[IPV4]: Convert address deletion to new netlink api

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

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

1 files changed, 29 insertions, 15 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 6b297c8697e6..309640e9ede1 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -430,34 +430,48 @@ struct in_ifaddr *inet_ifa_byprefix(struct in_device *in_dev, u32 prefix,
 
 static int inet_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 {
-        struct rtattr **rta = arg;
+        struct nlattr *tb[IFA_MAX+1];
         struct in_device *in_dev;
-        struct ifaddrmsg *ifm = NLMSG_DATA(nlh);
+        struct ifaddrmsg *ifm;
         struct in_ifaddr *ifa, **ifap;
+        int err = -EINVAL;
 
         ASSERT_RTNL();
 
-        if ((in_dev = inetdev_by_index(ifm->ifa_index)) == NULL)
-                goto out;
+        err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_ipv4_policy);
+        if (err < 0)
+                goto errout;
+
+        ifm = nlmsg_data(nlh);
+        in_dev = inetdev_by_index(ifm->ifa_index);
+        if (in_dev == NULL) {
+                err = -ENODEV;
+                goto errout;
+        }
+
         __in_dev_put(in_dev);
 
         for (ifap = &in_dev->ifa_list; (ifa = *ifap) != NULL;
              ifap = &ifa->ifa_next) {
-                if ((rta[IFA_LOCAL - 1] &&
-                     memcmp(RTA_DATA(rta[IFA_LOCAL - 1]),
-                            &ifa->ifa_local, 4)) ||
-                    (rta[IFA_LABEL - 1] &&
-                     rtattr_strcmp(rta[IFA_LABEL - 1], ifa->ifa_label)) ||
-                    (rta[IFA_ADDRESS - 1] &&
-                     (ifm->ifa_prefixlen != ifa->ifa_prefixlen ||
-                      !inet_ifa_match(*(u32*)RTA_DATA(rta[IFA_ADDRESS - 1]),
-                                      ifa))))
+                if (tb[IFA_LOCAL] &&
+                    ifa->ifa_local != nla_get_u32(tb[IFA_LOCAL]))
                         continue;
+
+                if (tb[IFA_LABEL] && nla_strcmp(tb[IFA_LABEL], ifa->ifa_label))
+                        continue;
+
+                if (tb[IFA_ADDRESS] &&
+                    (ifm->ifa_prefixlen != ifa->ifa_prefixlen ||
+                    !inet_ifa_match(nla_get_u32(tb[IFA_ADDRESS]), ifa)))
+                        continue;
+
                 inet_del_ifa(in_dev, ifap, 1);
                 return 0;
         }
-out:
-        return -EADDRNOTAVAIL;
+
+        err = -EADDRNOTAVAIL;
+errout:
+        return err;
 }
 
 static struct in_ifaddr *rtm_to_ifaddr(struct nlmsghdr *nlh)