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Commit 0626af31 authored by Eric Dumazet's avatar Eric Dumazet Committed by Pablo Neira Ayuso
Browse files

netfilter: take care of timewait sockets 



Sami Farin reported crashes in xt_LOG because it assumes skb->sk is a
full blown socket.

Since (41063e9d ipv4: Early TCP socket demux), we can have skb->sk
pointing to a timewait socket.

Same fix is needed in nfnetlink_log.

Diagnosed-by: default avatarFlorian Westphal <fw@strlen.de>
Reported-by: default avatarSami Farin <hvtaifwkbgefbaei@gmail.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 5b716ac7

net/netfilter/nfnetlink_log.c

+8 −6
Original line number Diff line number Diff line
@@ -381,6 +381,7 @@ __build_packet_message(struct nfulnl_instance *inst, 
	struct nlmsghdr *nlh;

	struct nfgenmsg *nfmsg;

	sk_buff_data_t old_tail = inst->skb->tail;

	struct sock *sk;



	nlh = nlmsg_put(inst->skb, 0, 0,

			NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
@@ -499,18 +500,19 @@ __build_packet_message(struct nfulnl_instance *inst, 
	}



	/* UID */

	if (skb->sk) {

		read_lock_bh(&skb->sk->sk_callback_lock);

		if (skb->sk->sk_socket && skb->sk->sk_socket->file) {

			struct file *file = skb->sk->sk_socket->file;

	sk = skb->sk;

	if (sk && sk->sk_state != TCP_TIME_WAIT) {

		read_lock_bh(&sk->sk_callback_lock);

		if (sk->sk_socket && sk->sk_socket->file) {

			struct file *file = sk->sk_socket->file;

			__be32 uid = htonl(file->f_cred->fsuid);

			__be32 gid = htonl(file->f_cred->fsgid);

			read_unlock_bh(&skb->sk->sk_callback_lock);

			read_unlock_bh(&sk->sk_callback_lock);

			if (nla_put_be32(inst->skb, NFULA_UID, uid) ||

			    nla_put_be32(inst->skb, NFULA_GID, gid))

				goto nla_put_failure;

		} else

			read_unlock_bh(&skb->sk->sk_callback_lock);

			read_unlock_bh(&sk->sk_callback_lock);

	}



	/* local sequence number */

net/netfilter/xt_LOG.c

+17 −16
Original line number Diff line number Diff line
@@ -145,6 +145,19 @@ static int dump_tcp_header(struct sbuff *m, const struct sk_buff *skb, 
	return 0;

}



static void dump_sk_uid_gid(struct sbuff *m, struct sock *sk)

{

	if (!sk || sk->sk_state == TCP_TIME_WAIT)

		return;



	read_lock_bh(&sk->sk_callback_lock);

	if (sk->sk_socket && sk->sk_socket->file)

		sb_add(m, "UID=%u GID=%u ",

			sk->sk_socket->file->f_cred->fsuid,

			sk->sk_socket->file->f_cred->fsgid);

	read_unlock_bh(&sk->sk_callback_lock);

}



/* One level of recursion won't kill us */

static void dump_ipv4_packet(struct sbuff *m,

			const struct nf_loginfo *info,
@@ -361,14 +374,8 @@ static void dump_ipv4_packet(struct sbuff *m, 
	}



	/* Max length: 15 "UID=4294967295 " */

	if ((logflags & XT_LOG_UID) && !iphoff && skb->sk) {

		read_lock_bh(&skb->sk->sk_callback_lock);

		if (skb->sk->sk_socket && skb->sk->sk_socket->file)

			sb_add(m, "UID=%u GID=%u ",

				skb->sk->sk_socket->file->f_cred->fsuid,

				skb->sk->sk_socket->file->f_cred->fsgid);

		read_unlock_bh(&skb->sk->sk_callback_lock);

	}

	if ((logflags & XT_LOG_UID) && !iphoff)

		dump_sk_uid_gid(m, skb->sk);



	/* Max length: 16 "MARK=0xFFFFFFFF " */

	if (!iphoff && skb->mark)
@@ -717,14 +724,8 @@ static void dump_ipv6_packet(struct sbuff *m, 
	}



	/* Max length: 15 "UID=4294967295 " */

	if ((logflags & XT_LOG_UID) && recurse && skb->sk) {

		read_lock_bh(&skb->sk->sk_callback_lock);

		if (skb->sk->sk_socket && skb->sk->sk_socket->file)

			sb_add(m, "UID=%u GID=%u ",

				skb->sk->sk_socket->file->f_cred->fsuid,

				skb->sk->sk_socket->file->f_cred->fsgid);

		read_unlock_bh(&skb->sk->sk_callback_lock);

	}

	if ((logflags & XT_LOG_UID) && recurse)

		dump_sk_uid_gid(m, skb->sk);



	/* Max length: 16 "MARK=0xFFFFFFFF " */

	if (!recurse && skb->mark)