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Commit 5f3d9cb2 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a915da9b

net/ipv4/tcp_ipv4.c

+4 −2
Original line number Diff line number Diff line
@@ -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);

	}

}