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Commit 89e357d8 authored by Yuejie Shi's avatar Yuejie Shi Committed by Steffen Klassert
Browse files

af_key: Add lock to key dump 



A dump may come in the middle of another dump, modifying its dump
structure members. This race condition will result in NULL pointer
dereference in kernel. So add a lock to prevent that race.

Fixes: 83321d6b ("[AF_KEY]: Dump SA/SP entries non-atomically")
Signed-off-by: default avatarYuejie Shi <syjcnss@gmail.com>
Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
parent 75514b66

net/key/af_key.c

+38 −8
Original line number Diff line number Diff line
@@ -63,6 +63,7 @@ struct pfkey_sock { 
		} u;

		struct sk_buff	*skb;

	} dump;

	struct mutex dump_lock;

};



static inline struct pfkey_sock *pfkey_sk(struct sock *sk)
@@ -139,6 +140,7 @@ static int pfkey_create(struct net *net, struct socket *sock, int protocol, 
{

	struct netns_pfkey *net_pfkey = net_generic(net, pfkey_net_id);

	struct sock *sk;

	struct pfkey_sock *pfk;

	int err;



	if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
@@ -153,6 +155,9 @@ static int pfkey_create(struct net *net, struct socket *sock, int protocol, 
	if (sk == NULL)

		goto out;



	pfk = pfkey_sk(sk);

	mutex_init(&pfk->dump_lock);



	sock->ops = &pfkey_ops;

	sock_init_data(sock, sk);
@@ -281,13 +286,23 @@ static int pfkey_do_dump(struct pfkey_sock *pfk) 
	struct sadb_msg *hdr;

	int rc;



	mutex_lock(&pfk->dump_lock);

	if (!pfk->dump.dump) {

		rc = 0;

		goto out;

	}



	rc = pfk->dump.dump(pfk);

	if (rc == -ENOBUFS)

		return 0;

	if (rc == -ENOBUFS) {

		rc = 0;

		goto out;

	}



	if (pfk->dump.skb) {

		if (!pfkey_can_dump(&pfk->sk))

			return 0;

		if (!pfkey_can_dump(&pfk->sk)) {

			rc = 0;

			goto out;

		}



		hdr = (struct sadb_msg *) pfk->dump.skb->data;

		hdr->sadb_msg_seq = 0;
@@ -298,6 +313,9 @@ static int pfkey_do_dump(struct pfkey_sock *pfk) 
	}



	pfkey_terminate_dump(pfk);



out:

	mutex_unlock(&pfk->dump_lock);

	return rc;

}
@@ -1793,19 +1811,26 @@ static int pfkey_dump(struct sock *sk, struct sk_buff *skb, const struct sadb_ms 
	struct xfrm_address_filter *filter = NULL;

	struct pfkey_sock *pfk = pfkey_sk(sk);



	if (pfk->dump.dump != NULL)

	mutex_lock(&pfk->dump_lock);

	if (pfk->dump.dump != NULL) {

		mutex_unlock(&pfk->dump_lock);

		return -EBUSY;

	}



	proto = pfkey_satype2proto(hdr->sadb_msg_satype);

	if (proto == 0)

	if (proto == 0) {

		mutex_unlock(&pfk->dump_lock);

		return -EINVAL;

	}



	if (ext_hdrs[SADB_X_EXT_FILTER - 1]) {

		struct sadb_x_filter *xfilter = ext_hdrs[SADB_X_EXT_FILTER - 1];



		filter = kmalloc(sizeof(*filter), GFP_KERNEL);

		if (filter == NULL)

		if (filter == NULL) {

			mutex_unlock(&pfk->dump_lock);

			return -ENOMEM;

		}



		memcpy(&filter->saddr, &xfilter->sadb_x_filter_saddr,

		       sizeof(xfrm_address_t));
@@ -1821,6 +1846,7 @@ static int pfkey_dump(struct sock *sk, struct sk_buff *skb, const struct sadb_ms 
	pfk->dump.dump = pfkey_dump_sa;

	pfk->dump.done = pfkey_dump_sa_done;

	xfrm_state_walk_init(&pfk->dump.u.state, proto, filter);

	mutex_unlock(&pfk->dump_lock);



	return pfkey_do_dump(pfk);

}
@@ -2679,14 +2705,18 @@ static int pfkey_spddump(struct sock *sk, struct sk_buff *skb, const struct sadb 
{

	struct pfkey_sock *pfk = pfkey_sk(sk);



	if (pfk->dump.dump != NULL)

	mutex_lock(&pfk->dump_lock);

	if (pfk->dump.dump != NULL) {

		mutex_unlock(&pfk->dump_lock);

		return -EBUSY;

	}



	pfk->dump.msg_version = hdr->sadb_msg_version;

	pfk->dump.msg_portid = hdr->sadb_msg_pid;

	pfk->dump.dump = pfkey_dump_sp;

	pfk->dump.done = pfkey_dump_sp_done;

	xfrm_policy_walk_init(&pfk->dump.u.policy, XFRM_POLICY_TYPE_MAIN);

	mutex_unlock(&pfk->dump_lock);



	return pfkey_do_dump(pfk);

}