From 0658cdc8f3babb4a441f5a803a0b644fafcbf9ef Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Sun, 28 Jul 2013 22:54:09 +0200 Subject: netfilter: nf_nat: fix locking in nf_nat_seq_adjust() nf_nat_seq_adjust() needs to grab nf_nat_seqofs_lock to protect against concurrent changes to the sequence adjustment data. Signed-off-by: Patrick McHardy Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_nat_helper.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'net/netfilter/nf_nat_helper.c') diff --git a/net/netfilter/nf_nat_helper.c b/net/netfilter/nf_nat_helper.c index 85e20a919081..a7262ed055c6 100644 --- a/net/netfilter/nf_nat_helper.c +++ b/net/netfilter/nf_nat_helper.c @@ -373,6 +373,7 @@ nf_nat_seq_adjust(struct sk_buff *skb, s16 seqoff, ackoff; struct nf_conn_nat *nat = nfct_nat(ct); struct nf_nat_seq *this_way, *other_way; + int res; dir = CTINFO2DIR(ctinfo); @@ -383,6 +384,7 @@ nf_nat_seq_adjust(struct sk_buff *skb, return 0; tcph = (void *)skb->data + protoff; + spin_lock_bh(&nf_nat_seqofs_lock); if (after(ntohl(tcph->seq), this_way->correction_pos)) seqoff = this_way->offset_after; else @@ -407,7 +409,10 @@ nf_nat_seq_adjust(struct sk_buff *skb, tcph->seq = newseq; tcph->ack_seq = newack; - return nf_nat_sack_adjust(skb, protoff, tcph, ct, ctinfo); + res = nf_nat_sack_adjust(skb, protoff, tcph, ct, ctinfo); + spin_unlock_bh(&nf_nat_seqofs_lock); + + return res; } /* Setup NAT on this expected conntrack so it follows master. */ -- cgit v1.2.3 From 2d89c68ac78ae432038ef23371d2fa949d725d43 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Sun, 28 Jul 2013 22:54:10 +0200 Subject: netfilter: nf_nat: change sequence number adjustments to 32 bits Using 16 bits is too small, when many adjustments happen the offsets might overflow and break the connection. Signed-off-by: Patrick McHardy Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_nat_helper.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'net/netfilter/nf_nat_helper.c') diff --git a/net/netfilter/nf_nat_helper.c b/net/netfilter/nf_nat_helper.c index a7262ed055c6..ff4a589e3e39 100644 --- a/net/netfilter/nf_nat_helper.c +++ b/net/netfilter/nf_nat_helper.c @@ -68,13 +68,13 @@ adjust_tcp_sequence(u32 seq, } /* Get the offset value, for conntrack */ -s16 nf_nat_get_offset(const struct nf_conn *ct, +s32 nf_nat_get_offset(const struct nf_conn *ct, enum ip_conntrack_dir dir, u32 seq) { struct nf_conn_nat *nat = nfct_nat(ct); struct nf_nat_seq *this_way; - s16 offset; + s32 offset; if (!nat) return 0; @@ -143,7 +143,7 @@ static int enlarge_skb(struct sk_buff *skb, unsigned int extra) } void nf_nat_set_seq_adjust(struct nf_conn *ct, enum ip_conntrack_info ctinfo, - __be32 seq, s16 off) + __be32 seq, s32 off) { if (!off) return; @@ -370,7 +370,7 @@ nf_nat_seq_adjust(struct sk_buff *skb, struct tcphdr *tcph; int dir; __be32 newseq, newack; - s16 seqoff, ackoff; + s32 seqoff, ackoff; struct nf_conn_nat *nat = nfct_nat(ct); struct nf_nat_seq *this_way, *other_way; int res; -- cgit v1.2.3 From 12e7ada385eada77854174ecaf469a0791277ddd Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Sun, 28 Jul 2013 22:54:11 +0200 Subject: netfilter: nf_nat: use per-conntrack locking for sequence number adjustments Get rid of the global lock and use per-conntrack locks for protecting the sequencen number adjustment data. Additionally saves one lock/unlock operation for every TCP packet. Signed-off-by: Patrick McHardy Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_nat_helper.c | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-) (limited to 'net/netfilter/nf_nat_helper.c') diff --git a/net/netfilter/nf_nat_helper.c b/net/netfilter/nf_nat_helper.c index ff4a589e3e39..46b9baa845a6 100644 --- a/net/netfilter/nf_nat_helper.c +++ b/net/netfilter/nf_nat_helper.c @@ -30,8 +30,6 @@ pr_debug("offset_before=%d, offset_after=%d, correction_pos=%u\n", \ x->offset_before, x->offset_after, x->correction_pos); -static DEFINE_SPINLOCK(nf_nat_seqofs_lock); - /* Setup TCP sequence correction given this change at this sequence */ static inline void adjust_tcp_sequence(u32 seq, @@ -49,7 +47,7 @@ adjust_tcp_sequence(u32 seq, pr_debug("adjust_tcp_sequence: Seq_offset before: "); DUMP_OFFSET(this_way); - spin_lock_bh(&nf_nat_seqofs_lock); + spin_lock_bh(&ct->lock); /* SYN adjust. If it's uninitialized, or this is after last * correction, record it: we don't handle more than one @@ -61,31 +59,26 @@ adjust_tcp_sequence(u32 seq, this_way->offset_before = this_way->offset_after; this_way->offset_after += sizediff; } - spin_unlock_bh(&nf_nat_seqofs_lock); + spin_unlock_bh(&ct->lock); pr_debug("adjust_tcp_sequence: Seq_offset after: "); DUMP_OFFSET(this_way); } -/* Get the offset value, for conntrack */ +/* Get the offset value, for conntrack. Caller must have the conntrack locked */ s32 nf_nat_get_offset(const struct nf_conn *ct, enum ip_conntrack_dir dir, u32 seq) { struct nf_conn_nat *nat = nfct_nat(ct); struct nf_nat_seq *this_way; - s32 offset; if (!nat) return 0; this_way = &nat->seq[dir]; - spin_lock_bh(&nf_nat_seqofs_lock); - offset = after(seq, this_way->correction_pos) + return after(seq, this_way->correction_pos) ? this_way->offset_after : this_way->offset_before; - spin_unlock_bh(&nf_nat_seqofs_lock); - - return offset; } /* Frobs data inside this packet, which is linear. */ @@ -384,7 +377,7 @@ nf_nat_seq_adjust(struct sk_buff *skb, return 0; tcph = (void *)skb->data + protoff; - spin_lock_bh(&nf_nat_seqofs_lock); + spin_lock_bh(&ct->lock); if (after(ntohl(tcph->seq), this_way->correction_pos)) seqoff = this_way->offset_after; else @@ -410,7 +403,7 @@ nf_nat_seq_adjust(struct sk_buff *skb, tcph->ack_seq = newack; res = nf_nat_sack_adjust(skb, protoff, tcph, ct, ctinfo); - spin_unlock_bh(&nf_nat_seqofs_lock); + spin_unlock_bh(&ct->lock); return res; } -- cgit v1.2.3 From 41d73ec053d2424599c4ed8452b889374d523ade Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Tue, 27 Aug 2013 08:50:12 +0200 Subject: netfilter: nf_conntrack: make sequence number adjustments usuable without NAT Split out sequence number adjustments from NAT and move them to the conntrack core to make them usable for SYN proxying. The sequence number adjustment information is moved to a seperate extend. The extend is added to new conntracks when a NAT mapping is set up for a connection using a helper. As a side effect, this saves 24 bytes per connection with NAT in the common case that a connection does not have a helper assigned. Signed-off-by: Patrick McHardy Tested-by: Martin Topholm Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_nat_helper.c | 228 +----------------------------------------- 1 file changed, 3 insertions(+), 225 deletions(-) (limited to 'net/netfilter/nf_nat_helper.c') diff --git a/net/netfilter/nf_nat_helper.c b/net/netfilter/nf_nat_helper.c index 46b9baa845a6..2840abb5bb99 100644 --- a/net/netfilter/nf_nat_helper.c +++ b/net/netfilter/nf_nat_helper.c @@ -20,67 +20,13 @@ #include #include #include +#include #include #include #include #include #include -#define DUMP_OFFSET(x) \ - pr_debug("offset_before=%d, offset_after=%d, correction_pos=%u\n", \ - x->offset_before, x->offset_after, x->correction_pos); - -/* Setup TCP sequence correction given this change at this sequence */ -static inline void -adjust_tcp_sequence(u32 seq, - int sizediff, - struct nf_conn *ct, - enum ip_conntrack_info ctinfo) -{ - enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); - struct nf_conn_nat *nat = nfct_nat(ct); - struct nf_nat_seq *this_way = &nat->seq[dir]; - - pr_debug("adjust_tcp_sequence: seq = %u, sizediff = %d\n", - seq, sizediff); - - pr_debug("adjust_tcp_sequence: Seq_offset before: "); - DUMP_OFFSET(this_way); - - spin_lock_bh(&ct->lock); - - /* SYN adjust. If it's uninitialized, or this is after last - * correction, record it: we don't handle more than one - * adjustment in the window, but do deal with common case of a - * retransmit */ - if (this_way->offset_before == this_way->offset_after || - before(this_way->correction_pos, seq)) { - this_way->correction_pos = seq; - this_way->offset_before = this_way->offset_after; - this_way->offset_after += sizediff; - } - spin_unlock_bh(&ct->lock); - - pr_debug("adjust_tcp_sequence: Seq_offset after: "); - DUMP_OFFSET(this_way); -} - -/* Get the offset value, for conntrack. Caller must have the conntrack locked */ -s32 nf_nat_get_offset(const struct nf_conn *ct, - enum ip_conntrack_dir dir, - u32 seq) -{ - struct nf_conn_nat *nat = nfct_nat(ct); - struct nf_nat_seq *this_way; - - if (!nat) - return 0; - - this_way = &nat->seq[dir]; - return after(seq, this_way->correction_pos) - ? this_way->offset_after : this_way->offset_before; -} - /* Frobs data inside this packet, which is linear. */ static void mangle_contents(struct sk_buff *skb, unsigned int dataoff, @@ -135,30 +81,6 @@ static int enlarge_skb(struct sk_buff *skb, unsigned int extra) return 1; } -void nf_nat_set_seq_adjust(struct nf_conn *ct, enum ip_conntrack_info ctinfo, - __be32 seq, s32 off) -{ - if (!off) - return; - set_bit(IPS_SEQ_ADJUST_BIT, &ct->status); - adjust_tcp_sequence(ntohl(seq), off, ct, ctinfo); - nf_conntrack_event_cache(IPCT_NATSEQADJ, ct); -} -EXPORT_SYMBOL_GPL(nf_nat_set_seq_adjust); - -void nf_nat_tcp_seq_adjust(struct sk_buff *skb, struct nf_conn *ct, - u32 ctinfo, int off) -{ - const struct tcphdr *th; - - if (nf_ct_protonum(ct) != IPPROTO_TCP) - return; - - th = (struct tcphdr *)(skb_network_header(skb)+ ip_hdrlen(skb)); - nf_nat_set_seq_adjust(ct, ctinfo, th->seq, off); -} -EXPORT_SYMBOL_GPL(nf_nat_tcp_seq_adjust); - /* Generic function for mangling variable-length address changes inside * NATed TCP connections (like the PORT XXX,XXX,XXX,XXX,XXX,XXX * command in FTP). @@ -203,8 +125,8 @@ int __nf_nat_mangle_tcp_packet(struct sk_buff *skb, datalen, oldlen); if (adjust && rep_len != match_len) - nf_nat_set_seq_adjust(ct, ctinfo, tcph->seq, - (int)rep_len - (int)match_len); + nf_ct_seqadj_set(ct, ctinfo, tcph->seq, + (int)rep_len - (int)match_len); return 1; } @@ -264,150 +186,6 @@ nf_nat_mangle_udp_packet(struct sk_buff *skb, } EXPORT_SYMBOL(nf_nat_mangle_udp_packet); -/* Adjust one found SACK option including checksum correction */ -static void -sack_adjust(struct sk_buff *skb, - struct tcphdr *tcph, - unsigned int sackoff, - unsigned int sackend, - struct nf_nat_seq *natseq) -{ - while (sackoff < sackend) { - struct tcp_sack_block_wire *sack; - __be32 new_start_seq, new_end_seq; - - sack = (void *)skb->data + sackoff; - if (after(ntohl(sack->start_seq) - natseq->offset_before, - natseq->correction_pos)) - new_start_seq = htonl(ntohl(sack->start_seq) - - natseq->offset_after); - else - new_start_seq = htonl(ntohl(sack->start_seq) - - natseq->offset_before); - - if (after(ntohl(sack->end_seq) - natseq->offset_before, - natseq->correction_pos)) - new_end_seq = htonl(ntohl(sack->end_seq) - - natseq->offset_after); - else - new_end_seq = htonl(ntohl(sack->end_seq) - - natseq->offset_before); - - pr_debug("sack_adjust: start_seq: %d->%d, end_seq: %d->%d\n", - ntohl(sack->start_seq), new_start_seq, - ntohl(sack->end_seq), new_end_seq); - - inet_proto_csum_replace4(&tcph->check, skb, - sack->start_seq, new_start_seq, 0); - inet_proto_csum_replace4(&tcph->check, skb, - sack->end_seq, new_end_seq, 0); - sack->start_seq = new_start_seq; - sack->end_seq = new_end_seq; - sackoff += sizeof(*sack); - } -} - -/* TCP SACK sequence number adjustment */ -static inline unsigned int -nf_nat_sack_adjust(struct sk_buff *skb, - unsigned int protoff, - struct tcphdr *tcph, - struct nf_conn *ct, - enum ip_conntrack_info ctinfo) -{ - unsigned int dir, optoff, optend; - struct nf_conn_nat *nat = nfct_nat(ct); - - optoff = protoff + sizeof(struct tcphdr); - optend = protoff + tcph->doff * 4; - - if (!skb_make_writable(skb, optend)) - return 0; - - dir = CTINFO2DIR(ctinfo); - - while (optoff < optend) { - /* Usually: option, length. */ - unsigned char *op = skb->data + optoff; - - switch (op[0]) { - case TCPOPT_EOL: - return 1; - case TCPOPT_NOP: - optoff++; - continue; - default: - /* no partial options */ - if (optoff + 1 == optend || - optoff + op[1] > optend || - op[1] < 2) - return 0; - if (op[0] == TCPOPT_SACK && - op[1] >= 2+TCPOLEN_SACK_PERBLOCK && - ((op[1] - 2) % TCPOLEN_SACK_PERBLOCK) == 0) - sack_adjust(skb, tcph, optoff+2, - optoff+op[1], &nat->seq[!dir]); - optoff += op[1]; - } - } - return 1; -} - -/* TCP sequence number adjustment. Returns 1 on success, 0 on failure */ -int -nf_nat_seq_adjust(struct sk_buff *skb, - struct nf_conn *ct, - enum ip_conntrack_info ctinfo, - unsigned int protoff) -{ - struct tcphdr *tcph; - int dir; - __be32 newseq, newack; - s32 seqoff, ackoff; - struct nf_conn_nat *nat = nfct_nat(ct); - struct nf_nat_seq *this_way, *other_way; - int res; - - dir = CTINFO2DIR(ctinfo); - - this_way = &nat->seq[dir]; - other_way = &nat->seq[!dir]; - - if (!skb_make_writable(skb, protoff + sizeof(*tcph))) - return 0; - - tcph = (void *)skb->data + protoff; - spin_lock_bh(&ct->lock); - if (after(ntohl(tcph->seq), this_way->correction_pos)) - seqoff = this_way->offset_after; - else - seqoff = this_way->offset_before; - - if (after(ntohl(tcph->ack_seq) - other_way->offset_before, - other_way->correction_pos)) - ackoff = other_way->offset_after; - else - ackoff = other_way->offset_before; - - newseq = htonl(ntohl(tcph->seq) + seqoff); - newack = htonl(ntohl(tcph->ack_seq) - ackoff); - - inet_proto_csum_replace4(&tcph->check, skb, tcph->seq, newseq, 0); - inet_proto_csum_replace4(&tcph->check, skb, tcph->ack_seq, newack, 0); - - pr_debug("Adjusting sequence number from %u->%u, ack from %u->%u\n", - ntohl(tcph->seq), ntohl(newseq), ntohl(tcph->ack_seq), - ntohl(newack)); - - tcph->seq = newseq; - tcph->ack_seq = newack; - - res = nf_nat_sack_adjust(skb, protoff, tcph, ct, ctinfo); - spin_unlock_bh(&ct->lock); - - return res; -} - /* Setup NAT on this expected conntrack so it follows master. */ /* If we fail to get a free NAT slot, we'll get dropped on confirm */ void nf_nat_follow_master(struct nf_conn *ct, -- cgit v1.2.3