// SPDX-License-Identifier: GPL-2.0-only /* (C) 1999-2001 Paul `Rusty' Russell * (C) 2002-2004 Netfilter Core Team */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include static const struct nf_loginfo default_loginfo = { .type = NF_LOG_TYPE_LOG, .u = { .log = { .level = LOGLEVEL_NOTICE, .logflags = NF_LOG_DEFAULT_MASK, }, }, }; /* One level of recursion won't kill us */ static void dump_ipv4_packet(struct net *net, struct nf_log_buf *m, const struct nf_loginfo *info, const struct sk_buff *skb, unsigned int iphoff) { struct iphdr _iph; const struct iphdr *ih; unsigned int logflags; if (info->type == NF_LOG_TYPE_LOG) logflags = info->u.log.logflags; else logflags = NF_LOG_DEFAULT_MASK; ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph); if (ih == NULL) { nf_log_buf_add(m, "TRUNCATED"); return; } /* Important fields: * TOS, len, DF/MF, fragment offset, TTL, src, dst, options. */ /* Max length: 40 "SRC=255.255.255.255 DST=255.255.255.255 " */ nf_log_buf_add(m, "SRC=%pI4 DST=%pI4 ", &ih->saddr, &ih->daddr); /* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */ nf_log_buf_add(m, "LEN=%u TOS=0x%02X PREC=0x%02X TTL=%u ID=%u ", ntohs(ih->tot_len), ih->tos & IPTOS_TOS_MASK, ih->tos & IPTOS_PREC_MASK, ih->ttl, ntohs(ih->id)); /* Max length: 6 "CE DF MF " */ if (ntohs(ih->frag_off) & IP_CE) nf_log_buf_add(m, "CE "); if (ntohs(ih->frag_off) & IP_DF) nf_log_buf_add(m, "DF "); if (ntohs(ih->frag_off) & IP_MF) nf_log_buf_add(m, "MF "); /* Max length: 11 "FRAG:65535 " */ if (ntohs(ih->frag_off) & IP_OFFSET) nf_log_buf_add(m, "FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET); if ((logflags & NF_LOG_IPOPT) && ih->ihl * 4 > sizeof(struct iphdr)) { const unsigned char *op; unsigned char _opt[4 * 15 - sizeof(struct iphdr)]; unsigned int i, optsize; optsize = ih->ihl * 4 - sizeof(struct iphdr); op = skb_header_pointer(skb, iphoff+sizeof(_iph), optsize, _opt); if (op == NULL) { nf_log_buf_add(m, "TRUNCATED"); return; } /* Max length: 127 "OPT (" 15*4*2chars ") " */ nf_log_buf_add(m, "OPT ("); for (i = 0; i < optsize; i++) nf_log_buf_add(m, "%02X", op[i]); nf_log_buf_add(m, ") "); } switch (ih->protocol) { case IPPROTO_TCP: if (nf_log_dump_tcp_header(m, skb, ih->protocol, ntohs(ih->frag_off) & IP_OFFSET, iphoff+ih->ihl*4, logflags)) return; break; case IPPROTO_UDP: case IPPROTO_UDPLITE: if (nf_log_dump_udp_header(m, skb, ih->protocol, ntohs(ih->frag_off) & IP_OFFSET, iphoff+ih->ihl*4)) return; break; case IPPROTO_ICMP: { struct icmphdr _icmph; const struct icmphdr *ich; static const size_t required_len[NR_ICMP_TYPES+1] = { [ICMP_ECHOREPLY] = 4, [ICMP_DEST_UNREACH] = 8 + sizeof(struct iphdr), [ICMP_SOURCE_QUENCH] = 8 + sizeof(struct iphdr), [ICMP_REDIRECT] = 8 + sizeof(struct iphdr), [ICMP_ECHO] = 4, [ICMP_TIME_EXCEEDED] = 8 + sizeof(struct iphdr), [ICMP_PARAMETERPROB] = 8 + sizeof(struct iphdr), [ICMP_TIMESTAMP] = 20, [ICMP_TIMESTAMPREPLY] = 20, [ICMP_ADDRESS] = 12, [ICMP_ADDRESSREPLY] = 12 }; /* Max length: 11 "PROTO=ICMP " */ nf_log_buf_add(m, "PROTO=ICMP "); if (ntohs(ih->frag_off) & IP_OFFSET) break; /* Max length: 25 "INCOMPLETE [65535 bytes] " */ ich = skb_header_pointer(skb, iphoff + ih->ihl * 4, sizeof(_icmph), &_icmph); if (ich == NULL) { nf_log_buf_add(m, "INCOMPLETE [%u bytes] ", skb->len - iphoff - ih->ihl*4); break; } /* Max length: 18 "TYPE=255 CODE=255 " */ nf_log_buf_add(m, "TYPE=%u CODE=%u ", ich->type, ich->code); /* Max length: 25 "INCOMPLETE [65535 bytes] " */ if (ich->type <= NR_ICMP_TYPES && required_len[ich->type] && skb->len-iphoff-ih->ihl*4 < required_len[ich->type]) { nf_log_buf_add(m, "INCOMPLETE [%u bytes] ", skb->len - iphoff - ih->ihl*4); break; } switch (ich->type) { case ICMP_ECHOREPLY: case ICMP_ECHO: /* Max length: 19 "ID=65535 SEQ=65535 " */ nf_log_buf_add(m, "ID=%u SEQ=%u ", ntohs(ich->un.echo.id), ntohs(ich->un.echo.sequence)); break; case ICMP_PARAMETERPROB: /* Max length: 14 "PARAMETER=255 " */ nf_log_buf_add(m, "PARAMETER=%u ", ntohl(ich->un.gateway) >> 24); break; case ICMP_REDIRECT: /* Max length: 24 "GATEWAY=255.255.255.255 " */ nf_log_buf_add(m, "GATEWAY=%pI4 ", &ich->un.gateway); /* Fall through */ case ICMP_DEST_UNREACH: case ICMP_SOURCE_QUENCH: case ICMP_TIME_EXCEEDED: /* Max length: 3+maxlen */ if (!iphoff) { /* Only recurse once. */ nf_log_buf_add(m, "["); dump_ipv4_packet(net, m, info, skb, iphoff + ih->ihl*4+sizeof(_icmph)); nf_log_buf_add(m, "] "); } /* Max length: 10 "MTU=65535 " */ if (ich->type == ICMP_DEST_UNREACH && ich->code == ICMP_FRAG_NEEDED) { nf_log_buf_add(m, "MTU=%u ", ntohs(ich->un.frag.mtu)); } } break; } /* Max Length */ case IPPROTO_AH: { struct ip_auth_hdr _ahdr; const struct ip_auth_hdr *ah; if (ntohs(ih->frag_off) & IP_OFFSET) break; /* Max length: 9 "PROTO=AH " */ nf_log_buf_add(m, "PROTO=AH "); /* Max length: 25 "INCOMPLETE [65535 bytes] " */ ah = skb_header_pointer(skb, iphoff+ih->ihl*4, sizeof(_ahdr), &_ahdr); if (ah == NULL) { nf_log_buf_add(m, "INCOMPLETE [%u bytes] ", skb->len - iphoff - ih->ihl*4); break; } /* Length: 15 "SPI=0xF1234567 " */ nf_log_buf_add(m, "SPI=0x%x ", ntohl(ah->spi)); break; } case IPPROTO_ESP: { struct ip_esp_hdr _esph; const struct ip_esp_hdr *eh; /* Max length: 10 "PROTO=ESP " */ nf_log_buf_add(m, "PROTO=ESP "); if (ntohs(ih->frag_off) & IP_OFFSET) break; /* Max length: 25 "INCOMPLETE [65535 bytes] " */ eh = skb_header_pointer(skb, iphoff+ih->ihl*4, sizeof(_esph), &_esph); if (eh == NULL) { nf_log_buf_add(m, "INCOMPLETE [%u bytes] ", skb->len - iphoff - ih->ihl*4); break; } /* Length: 15 "SPI=0xF1234567 " */ nf_log_buf_add(m, "SPI=0x%x ", ntohl(eh->spi)); break; } /* Max length: 10 "PROTO 255 " */ default: nf_log_buf_add(m, "PROTO=%u ", ih->protocol); } /* Max length: 15 "UID=4294967295 " */ if ((logflags & NF_LOG_UID) && !iphoff) nf_log_dump_sk_uid_gid(net, m, skb->sk); /* Max length: 16 "MARK=0xFFFFFFFF " */ if (!iphoff && skb->mark) nf_log_buf_add(m, "MARK=0x%x ", skb->mark); /* Proto Max log string length */ /* IP: 40+46+6+11+127 = 230 */ /* TCP: 10+max(25,20+30+13+9+32+11+127) = 252 */ /* UDP: 10+max(25,20) = 35 */ /* UDPLITE: 14+max(25,20) = 39 */ /* ICMP: 11+max(25, 18+25+max(19,14,24+3+n+10,3+n+10)) = 91+n */ /* ESP: 10+max(25)+15 = 50 */ /* AH: 9+max(25)+15 = 49 */ /* unknown: 10 */ /* (ICMP allows recursion one level deep) */ /* maxlen = IP + ICMP + IP + max(TCP,UDP,ICMP,unknown) */ /* maxlen = 230+ 91 + 230 + 252 = 803 */ } static void dump_ipv4_mac_header(struct nf_log_buf *m, const struct nf_loginfo *info, const struct sk_buff *skb) { struct net_device *dev = skb->dev; unsigned int logflags = 0; if (info->type == NF_LOG_TYPE_LOG) logflags = info->u.log.logflags; if (!(logflags & NF_LOG_MACDECODE)) goto fallback; switch (dev->type) { case ARPHRD_ETHER: nf_log_buf_add(m, "MACSRC=%pM MACDST=%pM ", eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest); nf_log_dump_vlan(m, skb); nf_log_buf_add(m, "MACPROTO=%04x ", ntohs(eth_hdr(skb)->h_proto)); return; default: break; } fallback: nf_log_buf_add(m, "MAC="); if (dev->hard_header_len && skb->mac_header != skb->network_header) { const unsigned char *p = skb_mac_header(skb); unsigned int i; nf_log_buf_add(m, "%02x", *p++); for (i = 1; i < dev->hard_header_len; i++, p++) nf_log_buf_add(m, ":%02x", *p); } nf_log_buf_add(m, " "); } static void nf_log_ip_packet(struct net *net, u_int8_t pf, unsigned int hooknum, const struct sk_buff *skb, const struct net_device *in, const struct net_device *out, const struct nf_loginfo *loginfo, const char *prefix) { struct nf_log_buf *m; /* FIXME: Disabled from containers until syslog ns is supported */ if (!net_eq(net, &init_net) && !sysctl_nf_log_all_netns) return; m = nf_log_buf_open(); if (!loginfo) loginfo = &default_loginfo; nf_log_dump_packet_common(m, pf, hooknum, skb, in, out, loginfo, prefix); if (in != NULL) dump_ipv4_mac_header(m, loginfo, skb); dump_ipv4_packet(net, m, loginfo, skb, 0); nf_log_buf_close(m); } static struct nf_logger nf_ip_logger __read_mostly = { .name = "nf_log_ipv4", .type = NF_LOG_TYPE_LOG, .logfn = nf_log_ip_packet, .me = THIS_MODULE, }; static int __net_init nf_log_ipv4_net_init(struct net *net) { return nf_log_set(net, NFPROTO_IPV4, &nf_ip_logger); } static void __net_exit nf_log_ipv4_net_exit(struct net *net) { nf_log_unset(net, &nf_ip_logger); } static struct pernet_operations nf_log_ipv4_net_ops = { .init = nf_log_ipv4_net_init, .exit = nf_log_ipv4_net_exit, }; static int __init nf_log_ipv4_init(void) { int ret; ret = register_pernet_subsys(&nf_log_ipv4_net_ops); if (ret < 0) return ret; ret = nf_log_register(NFPROTO_IPV4, &nf_ip_logger); if (ret < 0) { pr_err("failed to register logger\n"); goto err1; } return 0; err1: unregister_pernet_subsys(&nf_log_ipv4_net_ops); return ret; } static void __exit nf_log_ipv4_exit(void) { unregister_pernet_subsys(&nf_log_ipv4_net_ops); nf_log_unregister(&nf_ip_logger); } module_init(nf_log_ipv4_init); module_exit(nf_log_ipv4_exit); MODULE_AUTHOR("Netfilter Core Team "); MODULE_DESCRIPTION("Netfilter IPv4 packet logging"); MODULE_LICENSE("GPL"); MODULE_ALIAS_NF_LOGGER(AF_INET, 0);