tcp: md5: use sock_kmalloc() to limit md5 keys

There is no limit on number of MD5 keys an application can attach to a
tcp socket.

This patch adds a per tcp socket limit based
on /proc/sys/net/core/optmem_max

With current default optmem_max values, this allows about 150 keys on
64bit arches, and 88 keys on 32bit arches.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 1d5fd82c5c08c158549f2655cc2478917775e2d4..da5d3226771b78841740b47f2e469d89d250cd82 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -943,11 +943,11 @@ int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
                tp->md5sig_info = md5sig;
        }
 
-       key = kmalloc(sizeof(*key), gfp);
+       key = sock_kmalloc(sk, sizeof(*key), gfp);
        if (!key)
                return -ENOMEM;
        if (hlist_empty(&md5sig->head) && !tcp_alloc_md5sig_pool(sk)) {
-               kfree(key);
+               sock_kfree_s(sk, key, sizeof(*key));
                return -ENOMEM;
        }
 
@@ -971,6 +971,7 @@ int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
        if (!key)
                return -ENOENT;
        hlist_del_rcu(&key->node);
+       atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
        kfree_rcu(key, rcu);
        if (hlist_empty(&tp->md5sig_info->head))
                tcp_free_md5sig_pool();
@@ -988,6 +989,7 @@ void tcp_clear_md5_list(struct sock *sk)
                tcp_free_md5sig_pool();
        hlist_for_each_entry_safe(key, pos, n, &tp->md5sig_info->head, node) {
                hlist_del_rcu(&key->node);
+               atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
                kfree_rcu(key, rcu);
        }
 }