| /* (C) 1999-2001 Paul `Rusty' Russell |
| * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> |
| * (C) 2006-2010 Patrick McHardy <kaber@trash.net> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| */ |
| |
| #include <linux/types.h> |
| #include <linux/timer.h> |
| #include <linux/netfilter.h> |
| #include <linux/in.h> |
| #include <linux/icmp.h> |
| #include <linux/seq_file.h> |
| #include <net/ip.h> |
| #include <net/checksum.h> |
| #include <linux/netfilter_ipv4.h> |
| #include <net/netfilter/nf_conntrack_tuple.h> |
| #include <net/netfilter/nf_conntrack_l4proto.h> |
| #include <net/netfilter/nf_conntrack_core.h> |
| #include <net/netfilter/nf_conntrack_zones.h> |
| #include <net/netfilter/nf_log.h> |
| |
| static unsigned int nf_ct_icmp_timeout __read_mostly = 30*HZ; |
| |
| static inline struct nf_icmp_net *icmp_pernet(struct net *net) |
| { |
| return &net->ct.nf_ct_proto.icmp; |
| } |
| |
| static bool icmp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff, |
| struct nf_conntrack_tuple *tuple) |
| { |
| const struct icmphdr *hp; |
| struct icmphdr _hdr; |
| |
| hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr); |
| if (hp == NULL) |
| return false; |
| |
| tuple->dst.u.icmp.type = hp->type; |
| tuple->src.u.icmp.id = hp->un.echo.id; |
| tuple->dst.u.icmp.code = hp->code; |
| |
| return true; |
| } |
| |
| /* Add 1; spaces filled with 0. */ |
| static const u_int8_t invmap[] = { |
| [ICMP_ECHO] = ICMP_ECHOREPLY + 1, |
| [ICMP_ECHOREPLY] = ICMP_ECHO + 1, |
| [ICMP_TIMESTAMP] = ICMP_TIMESTAMPREPLY + 1, |
| [ICMP_TIMESTAMPREPLY] = ICMP_TIMESTAMP + 1, |
| [ICMP_INFO_REQUEST] = ICMP_INFO_REPLY + 1, |
| [ICMP_INFO_REPLY] = ICMP_INFO_REQUEST + 1, |
| [ICMP_ADDRESS] = ICMP_ADDRESSREPLY + 1, |
| [ICMP_ADDRESSREPLY] = ICMP_ADDRESS + 1 |
| }; |
| |
| static bool icmp_invert_tuple(struct nf_conntrack_tuple *tuple, |
| const struct nf_conntrack_tuple *orig) |
| { |
| if (orig->dst.u.icmp.type >= sizeof(invmap) || |
| !invmap[orig->dst.u.icmp.type]) |
| return false; |
| |
| tuple->src.u.icmp.id = orig->src.u.icmp.id; |
| tuple->dst.u.icmp.type = invmap[orig->dst.u.icmp.type] - 1; |
| tuple->dst.u.icmp.code = orig->dst.u.icmp.code; |
| return true; |
| } |
| |
| /* Print out the per-protocol part of the tuple. */ |
| static int icmp_print_tuple(struct seq_file *s, |
| const struct nf_conntrack_tuple *tuple) |
| { |
| return seq_printf(s, "type=%u code=%u id=%u ", |
| tuple->dst.u.icmp.type, |
| tuple->dst.u.icmp.code, |
| ntohs(tuple->src.u.icmp.id)); |
| } |
| |
| static unsigned int *icmp_get_timeouts(struct net *net) |
| { |
| return &icmp_pernet(net)->timeout; |
| } |
| |
| /* Returns verdict for packet, or -1 for invalid. */ |
| static int icmp_packet(struct nf_conn *ct, |
| const struct sk_buff *skb, |
| unsigned int dataoff, |
| enum ip_conntrack_info ctinfo, |
| u_int8_t pf, |
| unsigned int hooknum, |
| unsigned int *timeout) |
| { |
| /* Do not immediately delete the connection after the first |
| successful reply to avoid excessive conntrackd traffic |
| and also to handle correctly ICMP echo reply duplicates. */ |
| nf_ct_refresh_acct(ct, ctinfo, skb, *timeout); |
| |
| return NF_ACCEPT; |
| } |
| |
| /* Called when a new connection for this protocol found. */ |
| static bool icmp_new(struct nf_conn *ct, const struct sk_buff *skb, |
| unsigned int dataoff, unsigned int *timeouts) |
| { |
| static const u_int8_t valid_new[] = { |
| [ICMP_ECHO] = 1, |
| [ICMP_TIMESTAMP] = 1, |
| [ICMP_INFO_REQUEST] = 1, |
| [ICMP_ADDRESS] = 1 |
| }; |
| |
| if (ct->tuplehash[0].tuple.dst.u.icmp.type >= sizeof(valid_new) || |
| !valid_new[ct->tuplehash[0].tuple.dst.u.icmp.type]) { |
| /* Can't create a new ICMP `conn' with this. */ |
| pr_debug("icmp: can't create new conn with type %u\n", |
| ct->tuplehash[0].tuple.dst.u.icmp.type); |
| nf_ct_dump_tuple_ip(&ct->tuplehash[0].tuple); |
| return false; |
| } |
| return true; |
| } |
| |
| /* Returns conntrack if it dealt with ICMP, and filled in skb fields */ |
| static int |
| icmp_error_message(struct net *net, struct nf_conn *tmpl, struct sk_buff *skb, |
| enum ip_conntrack_info *ctinfo, |
| unsigned int hooknum) |
| { |
| struct nf_conntrack_tuple innertuple, origtuple; |
| const struct nf_conntrack_l4proto *innerproto; |
| const struct nf_conntrack_tuple_hash *h; |
| u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; |
| |
| NF_CT_ASSERT(skb->nfct == NULL); |
| |
| /* Are they talking about one of our connections? */ |
| if (!nf_ct_get_tuplepr(skb, |
| skb_network_offset(skb) + ip_hdrlen(skb) |
| + sizeof(struct icmphdr), |
| PF_INET, &origtuple)) { |
| pr_debug("icmp_error_message: failed to get tuple\n"); |
| return -NF_ACCEPT; |
| } |
| |
| /* rcu_read_lock()ed by nf_hook_slow */ |
| innerproto = __nf_ct_l4proto_find(PF_INET, origtuple.dst.protonum); |
| |
| /* Ordinarily, we'd expect the inverted tupleproto, but it's |
| been preserved inside the ICMP. */ |
| if (!nf_ct_invert_tuple(&innertuple, &origtuple, |
| &nf_conntrack_l3proto_ipv4, innerproto)) { |
| pr_debug("icmp_error_message: no match\n"); |
| return -NF_ACCEPT; |
| } |
| |
| *ctinfo = IP_CT_RELATED; |
| |
| h = nf_conntrack_find_get(net, zone, &innertuple); |
| if (!h) { |
| pr_debug("icmp_error_message: no match\n"); |
| return -NF_ACCEPT; |
| } |
| |
| if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) |
| *ctinfo += IP_CT_IS_REPLY; |
| |
| /* Update skb to refer to this connection */ |
| skb->nfct = &nf_ct_tuplehash_to_ctrack(h)->ct_general; |
| skb->nfctinfo = *ctinfo; |
| return NF_ACCEPT; |
| } |
| |
| /* Small and modified version of icmp_rcv */ |
| static int |
| icmp_error(struct net *net, struct nf_conn *tmpl, |
| struct sk_buff *skb, unsigned int dataoff, |
| enum ip_conntrack_info *ctinfo, u_int8_t pf, unsigned int hooknum) |
| { |
| const struct icmphdr *icmph; |
| struct icmphdr _ih; |
| |
| /* Not enough header? */ |
| icmph = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_ih), &_ih); |
| if (icmph == NULL) { |
| if (LOG_INVALID(net, IPPROTO_ICMP)) |
| nf_log_packet(net, PF_INET, 0, skb, NULL, NULL, |
| NULL, "nf_ct_icmp: short packet "); |
| return -NF_ACCEPT; |
| } |
| |
| /* See ip_conntrack_proto_tcp.c */ |
| if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING && |
| nf_ip_checksum(skb, hooknum, dataoff, 0)) { |
| if (LOG_INVALID(net, IPPROTO_ICMP)) |
| nf_log_packet(net, PF_INET, 0, skb, NULL, NULL, NULL, |
| "nf_ct_icmp: bad HW ICMP checksum "); |
| return -NF_ACCEPT; |
| } |
| |
| /* |
| * 18 is the highest 'known' ICMP type. Anything else is a mystery |
| * |
| * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently |
| * discarded. |
| */ |
| if (icmph->type > NR_ICMP_TYPES) { |
| if (LOG_INVALID(net, IPPROTO_ICMP)) |
| nf_log_packet(net, PF_INET, 0, skb, NULL, NULL, NULL, |
| "nf_ct_icmp: invalid ICMP type "); |
| return -NF_ACCEPT; |
| } |
| |
| /* Need to track icmp error message? */ |
| if (icmph->type != ICMP_DEST_UNREACH && |
| icmph->type != ICMP_SOURCE_QUENCH && |
| icmph->type != ICMP_TIME_EXCEEDED && |
| icmph->type != ICMP_PARAMETERPROB && |
| icmph->type != ICMP_REDIRECT) |
| return NF_ACCEPT; |
| |
| return icmp_error_message(net, tmpl, skb, ctinfo, hooknum); |
| } |
| |
| #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) |
| |
| #include <linux/netfilter/nfnetlink.h> |
| #include <linux/netfilter/nfnetlink_conntrack.h> |
| |
| static int icmp_tuple_to_nlattr(struct sk_buff *skb, |
| const struct nf_conntrack_tuple *t) |
| { |
| if (nla_put_be16(skb, CTA_PROTO_ICMP_ID, t->src.u.icmp.id) || |
| nla_put_u8(skb, CTA_PROTO_ICMP_TYPE, t->dst.u.icmp.type) || |
| nla_put_u8(skb, CTA_PROTO_ICMP_CODE, t->dst.u.icmp.code)) |
| goto nla_put_failure; |
| return 0; |
| |
| nla_put_failure: |
| return -1; |
| } |
| |
| static const struct nla_policy icmp_nla_policy[CTA_PROTO_MAX+1] = { |
| [CTA_PROTO_ICMP_TYPE] = { .type = NLA_U8 }, |
| [CTA_PROTO_ICMP_CODE] = { .type = NLA_U8 }, |
| [CTA_PROTO_ICMP_ID] = { .type = NLA_U16 }, |
| }; |
| |
| static int icmp_nlattr_to_tuple(struct nlattr *tb[], |
| struct nf_conntrack_tuple *tuple) |
| { |
| if (!tb[CTA_PROTO_ICMP_TYPE] || |
| !tb[CTA_PROTO_ICMP_CODE] || |
| !tb[CTA_PROTO_ICMP_ID]) |
| return -EINVAL; |
| |
| tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMP_TYPE]); |
| tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMP_CODE]); |
| tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMP_ID]); |
| |
| if (tuple->dst.u.icmp.type >= sizeof(invmap) || |
| !invmap[tuple->dst.u.icmp.type]) |
| return -EINVAL; |
| |
| return 0; |
| } |
| |
| static int icmp_nlattr_tuple_size(void) |
| { |
| return nla_policy_len(icmp_nla_policy, CTA_PROTO_MAX + 1); |
| } |
| #endif |
| |
| #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT) |
| |
| #include <linux/netfilter/nfnetlink.h> |
| #include <linux/netfilter/nfnetlink_cttimeout.h> |
| |
| static int icmp_timeout_nlattr_to_obj(struct nlattr *tb[], |
| struct net *net, void *data) |
| { |
| unsigned int *timeout = data; |
| struct nf_icmp_net *in = icmp_pernet(net); |
| |
| if (tb[CTA_TIMEOUT_ICMP_TIMEOUT]) { |
| *timeout = |
| ntohl(nla_get_be32(tb[CTA_TIMEOUT_ICMP_TIMEOUT])) * HZ; |
| } else { |
| /* Set default ICMP timeout. */ |
| *timeout = in->timeout; |
| } |
| return 0; |
| } |
| |
| static int |
| icmp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data) |
| { |
| const unsigned int *timeout = data; |
| |
| if (nla_put_be32(skb, CTA_TIMEOUT_ICMP_TIMEOUT, htonl(*timeout / HZ))) |
| goto nla_put_failure; |
| return 0; |
| |
| nla_put_failure: |
| return -ENOSPC; |
| } |
| |
| static const struct nla_policy |
| icmp_timeout_nla_policy[CTA_TIMEOUT_ICMP_MAX+1] = { |
| [CTA_TIMEOUT_ICMP_TIMEOUT] = { .type = NLA_U32 }, |
| }; |
| #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */ |
| |
| #ifdef CONFIG_SYSCTL |
| static struct ctl_table icmp_sysctl_table[] = { |
| { |
| .procname = "nf_conntrack_icmp_timeout", |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { } |
| }; |
| #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT |
| static struct ctl_table icmp_compat_sysctl_table[] = { |
| { |
| .procname = "ip_conntrack_icmp_timeout", |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_jiffies, |
| }, |
| { } |
| }; |
| #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */ |
| #endif /* CONFIG_SYSCTL */ |
| |
| static int icmp_kmemdup_sysctl_table(struct nf_proto_net *pn, |
| struct nf_icmp_net *in) |
| { |
| #ifdef CONFIG_SYSCTL |
| pn->ctl_table = kmemdup(icmp_sysctl_table, |
| sizeof(icmp_sysctl_table), |
| GFP_KERNEL); |
| if (!pn->ctl_table) |
| return -ENOMEM; |
| |
| pn->ctl_table[0].data = &in->timeout; |
| #endif |
| return 0; |
| } |
| |
| static int icmp_kmemdup_compat_sysctl_table(struct nf_proto_net *pn, |
| struct nf_icmp_net *in) |
| { |
| #ifdef CONFIG_SYSCTL |
| #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT |
| pn->ctl_compat_table = kmemdup(icmp_compat_sysctl_table, |
| sizeof(icmp_compat_sysctl_table), |
| GFP_KERNEL); |
| if (!pn->ctl_compat_table) |
| return -ENOMEM; |
| |
| pn->ctl_compat_table[0].data = &in->timeout; |
| #endif |
| #endif |
| return 0; |
| } |
| |
| static int icmp_init_net(struct net *net, u_int16_t proto) |
| { |
| int ret; |
| struct nf_icmp_net *in = icmp_pernet(net); |
| struct nf_proto_net *pn = &in->pn; |
| |
| in->timeout = nf_ct_icmp_timeout; |
| |
| ret = icmp_kmemdup_compat_sysctl_table(pn, in); |
| if (ret < 0) |
| return ret; |
| |
| ret = icmp_kmemdup_sysctl_table(pn, in); |
| if (ret < 0) |
| nf_ct_kfree_compat_sysctl_table(pn); |
| |
| return ret; |
| } |
| |
| static struct nf_proto_net *icmp_get_net_proto(struct net *net) |
| { |
| return &net->ct.nf_ct_proto.icmp.pn; |
| } |
| |
| struct nf_conntrack_l4proto nf_conntrack_l4proto_icmp __read_mostly = |
| { |
| .l3proto = PF_INET, |
| .l4proto = IPPROTO_ICMP, |
| .name = "icmp", |
| .pkt_to_tuple = icmp_pkt_to_tuple, |
| .invert_tuple = icmp_invert_tuple, |
| .print_tuple = icmp_print_tuple, |
| .packet = icmp_packet, |
| .get_timeouts = icmp_get_timeouts, |
| .new = icmp_new, |
| .error = icmp_error, |
| .destroy = NULL, |
| .me = NULL, |
| #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) |
| .tuple_to_nlattr = icmp_tuple_to_nlattr, |
| .nlattr_tuple_size = icmp_nlattr_tuple_size, |
| .nlattr_to_tuple = icmp_nlattr_to_tuple, |
| .nla_policy = icmp_nla_policy, |
| #endif |
| #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT) |
| .ctnl_timeout = { |
| .nlattr_to_obj = icmp_timeout_nlattr_to_obj, |
| .obj_to_nlattr = icmp_timeout_obj_to_nlattr, |
| .nlattr_max = CTA_TIMEOUT_ICMP_MAX, |
| .obj_size = sizeof(unsigned int), |
| .nla_policy = icmp_timeout_nla_policy, |
| }, |
| #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */ |
| .init_net = icmp_init_net, |
| .get_net_proto = icmp_get_net_proto, |
| }; |