net: rtm_to_ifaddr: free ifa if ifa_cacheinfo processing fails

Commit 5c766d64 ("ipv4: introduce address lifetime") leaves the ifa
resource that was allocated via inet_alloc_ifa() unfreed when returning
the function with -EINVAL. Thus, free it first via inet_free_ifa().
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Reviewed-by: NJiri Pirko <jiri@resnulli.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/devinet.c

@@ -772,7 +772,7 @@ static struct in_ifaddr *rtm_to_ifaddr(struct net *net, struct nlmsghdr *nlh,
 		ci = nla_data(tb[IFA_CACHEINFO]);
 		if (!ci->ifa_valid || ci->ifa_prefered > ci->ifa_valid) {
 			err = -EINVAL;
-			goto errout;
+			goto errout_free;
 		}
 		*pvalid_lft = ci->ifa_valid;
 		*pprefered_lft = ci->ifa_prefered;
@@ -780,6 +780,8 @@ static struct in_ifaddr *rtm_to_ifaddr(struct net *net, struct nlmsghdr *nlh,
 
 	return ifa;
 
+errout_free:
+	inet_free_ifa(ifa);
 errout:
 	return ERR_PTR(err);
 }