Commit d2508893 authored by Florian Westphal's avatar Florian Westphal
Browse files

netfilter: nf_ct_ftp: fix deadlock when nat rewrite is needed 



We can't use ct->lock, this is already used by the seqadj internals.
When using ftp helper + nat, seqadj will attempt to acquire ct->lock
again.

Revert back to a global lock for now.

Fixes: c783a29c ("netfilter: nf_ct_ftp: prefer skb_linearize")
Reported-by: default avatarBruno de Paula Larini <bruno.larini@riosoft.com.br>
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
parent 62ce44c4

net/netfilter/nf_conntrack_ftp.c

+4 −2
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>"); 
MODULE_DESCRIPTION("ftp connection tracking helper");

MODULE_ALIAS("ip_conntrack_ftp");

MODULE_ALIAS_NFCT_HELPER(HELPER_NAME);

static DEFINE_SPINLOCK(nf_ftp_lock);



#define MAX_PORTS 8

static u_int16_t ports[MAX_PORTS];
@@ -409,7 +410,8 @@ static int help(struct sk_buff *skb, 
	}

	datalen = skb->len - dataoff;



	spin_lock_bh(&ct->lock);

	/* seqadj (nat) uses ct->lock internally, nf_nat_ftp would cause deadlock */

	spin_lock_bh(&nf_ftp_lock);

	fb_ptr = skb->data + dataoff;



	ends_in_nl = (fb_ptr[datalen - 1] == '\n');
@@ -538,7 +540,7 @@ static int help(struct sk_buff *skb, 
	if (ends_in_nl)

		update_nl_seq(ct, seq, ct_ftp_info, dir, skb);

 out:

	spin_unlock_bh(&ct->lock);

	spin_unlock_bh(&nf_ftp_lock);

	return ret;

}