/* * This is a module which is used for logging packets. */ /* (C) 1999-2001 Paul `Rusty' Russell * (C) 2002-2004 Netfilter Core Team * * 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 #include #include #include #include #include #include #include #include #include #include MODULE_LICENSE("GPL"); MODULE_AUTHOR("Netfilter Core Team "); MODULE_DESCRIPTION("iptables syslog logging module"); static unsigned int nflog = 1; module_param(nflog, int, 0400); MODULE_PARM_DESC(nflog, "register as internal netfilter logging module"); #if 0 #define DEBUGP printk #else #define DEBUGP(format, args...) #endif /* Use lock to serialize, so printks don't overlap */ static DEFINE_SPINLOCK(log_lock); /* One level of recursion won't kill us */ static void dump_packet(const struct ipt_log_info *info, const struct sk_buff *skb, unsigned int iphoff) { struct iphdr _iph, *ih; ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph); if (ih == NULL) { printk("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 " */ printk("SRC=%u.%u.%u.%u DST=%u.%u.%u.%u ", NIPQUAD(ih->saddr), NIPQUAD(ih->daddr)); /* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */ printk("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) printk("CE "); if (ntohs(ih->frag_off) & IP_DF) printk("DF "); if (ntohs(ih->frag_off) & IP_MF) printk("MF "); /* Max length: 11 "FRAG:65535 " */ if (ntohs(ih->frag_off) & IP_OFFSET) printk("FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET); if ((info->logflags & IPT_LOG_IPOPT) && ih->ihl * 4 > sizeof(struct iphdr)) { unsigned char _opt[4 * 15 - sizeof(struct iphdr)], *op; unsigned int i, optsize; optsize = ih->ihl * 4 - sizeof(struct iphdr); op = skb_header_pointer(skb, iphoff+sizeof(_iph), optsize, _opt); if (op == NULL) { printk("TRUNCATED"); return; } /* Max length: 127 "OPT (" 15*4*2chars ") " */ printk("OPT ("); for (i = 0; i < optsize; i++) printk("%02X", op[i]); printk(") "); } switch (ih->protocol) { case IPPROTO_TCP: { struct tcphdr _tcph, *th; /* Max length: 10 "PROTO=TCP " */ printk("PROTO=TCP "); if (ntohs(ih->frag_off) & IP_OFFSET) break; /* Max length: 25 "INCOMPLETE [65535 bytes] " */ th = skb_header_pointer(skb, iphoff + ih->ihl * 4, sizeof(_tcph), &_tcph); if (th == NULL) { printk("INCOMPLETE [%u bytes] ", skb->len - iphoff - ih->ihl*4); break; } /* Max length: 20 "SPT=65535 DPT=65535 " */ printk("SPT=%u DPT=%u ", ntohs(th->source), ntohs(th->dest)); /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */ if (info->logflags & IPT_LOG_TCPSEQ) printk("SEQ=%u ACK=%u ", ntohl(th->seq), ntohl(th->ack_seq)); /* Max length: 13 "WINDOW=65535 " */ printk("WINDOW=%u ", ntohs(th->window)); /* Max length: 9 "RES=0x3F " */ printk("RES=0x%02x ", (u8)(ntohl(tcp_flag_word(th) & TCP_RESERVED_BITS) >> 22)); /* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */ if (th->cwr) printk("CWR "); if (th->ece) printk("ECE "); if (th->urg) printk("URG "); if (th->ack) printk("ACK "); if (th->psh) printk("PSH "); if (th->rst) printk("RST "); if (th->syn) printk("SYN "); if (th->fin) printk("FIN "); /* Max length: 11 "URGP=65535 " */ printk("URGP=%u ", ntohs(th->urg_ptr)); if ((info->logflags & IPT_LOG_TCPOPT) && th->doff * 4 > sizeof(struct tcphdr)) { unsigned char _opt[4 * 15 - sizeof(struct tcphdr)]; unsigned char *op; unsigned int i, optsize; optsize = th->doff * 4 - sizeof(struct tcphdr); op = skb_header_pointer(skb, iphoff+ih->ihl*4+sizeof(_tcph), optsize, _opt); if (op == NULL) { printk("TRUNCATED"); return; } /* Max length: 127 "OPT (" 15*4*2chars ") " */ printk("OPT ("); for (i = 0; i < optsize; i++) printk("%02X", op[i]); printk(") "); } break; } case IPPROTO_UDP: { struct udphdr _udph, *uh; /* Max length: 10 "PROTO=UDP " */ printk("PROTO=UDP "); if (ntohs(ih->frag_off) & IP_OFFSET) break; /* Max length: 25 "INCOMPLETE [65535 bytes] " */ uh = skb_header_pointer(skb, iphoff+ih->ihl*4, sizeof(_udph), &_udph); if (uh == NULL) { printk("INCOMPLETE [%u bytes] ", skb->len - iphoff - ih->ihl*4); break; } /* Max length: 20 "SPT=65535 DPT=65535 " */ printk("SPT=%u DPT=%u LEN=%u ", ntohs(uh->source), ntohs(uh->dest), ntohs(uh->len)); break; } case IPPROTO_ICMP: { struct icmphdr _icmph, *ich; static 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 " */ printk("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) { printk("INCOMPLETE [%u bytes] ", skb->len - iphoff - ih->ihl*4); break; } /* Max length: 18 "TYPE=255 CODE=255 " */ printk("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]) { printk("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 " */ printk("ID=%u SEQ=%u ", ntohs(ich->un.echo.id), ntohs(ich->un.echo.sequence)); break; case ICMP_PARAMETERPROB: /* Max length: 14 "PARAMETER=255 " */ printk("PARAMETER=%u ", ntohl(ich->un.gateway) >> 24); break; case ICMP_REDIRECT: /* Max length: 24 "GATEWAY=255.255.255.255 " */ printk("GATEWAY=%u.%u.%u.%u ", NIPQUAD(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. */ printk("["); dump_packet(info, skb, iphoff + ih->ihl*4+sizeof(_icmph)); printk("] "); } /* Max length: 10 "MTU=65535 " */ if (ich->type == ICMP_DEST_UNREACH && ich->code == ICMP_FRAG_NEEDED) printk("MTU=%u ", ntohs(ich->un.frag.mtu)); } break; } /* Max Length */ case IPPROTO_AH: { struct ip_auth_hdr _ahdr, *ah; if (ntohs(ih->frag_off) & IP_OFFSET) break; /* Max length: 9 "PROTO=AH " */ printk("PROTO=AH "); /* Max length: 25 "INCOMPLETE [65535 bytes] " */ ah = skb_header_pointer(skb, iphoff+ih->ihl*4, sizeof(_ahdr), &_ahdr); if (ah == NULL) { printk("INCOMPLETE [%u bytes] ", skb->len - iphoff - ih->ihl*4); break; } /* Length: 15 "SPI=0xF1234567 " */ printk("SPI=0x%x ", ntohl(ah->spi)); break; } case IPPROTO_ESP: { struct ip_esp_hdr _esph, *eh; /* Max length: 10 "PROTO=ESP " */ printk("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) { printk("INCOMPLETE [%u bytes] ", skb->len - iphoff - ih->ihl*4); break; } /* Length: 15 "SPI=0xF1234567 " */ printk("SPI=0x%x ", ntohl(eh->spi)); break; } /* Max length: 10 "PROTO 255 " */ default: printk("PROTO=%u ", ih->protocol); } /* Max length: 15 "UID=4294967295 " */ if ((info->logflags & IPT_LOG_UID) && !iphoff && skb->sk) { read_lock_bh(&skb->sk->sk_callback_lock); if (skb->sk->sk_socket && skb->sk->sk_socket->file) printk("UID=%u ", skb->sk->sk_socket->file->f_uid); read_unlock_bh(&skb->sk->sk_callback_lock); } /* 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 */ /* 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 ipt_log_packet(unsigned int hooknum, const struct sk_buff *skb, const struct net_device *in, const struct net_device *out, const struct ipt_log_info *loginfo, const char *level_string, const char *prefix) { spin_lock_bh(&log_lock); printk(level_string); printk("%sIN=%s OUT=%s ", prefix == NULL ? loginfo->prefix : prefix, in ? in->name : "", out ? out->name : ""); #ifdef CONFIG_BRIDGE_NETFILTER if (skb->nf_bridge) { struct net_device *physindev = skb->nf_bridge->physindev; struct net_device *physoutdev = skb->nf_bridge->physoutdev; if (physindev && in != physindev) printk("PHYSIN=%s ", physindev->name); if (physoutdev && out != physoutdev) printk("PHYSOUT=%s ", physoutdev->name); } #endif if (in && !out) { /* MAC logging for input chain only. */ printk("MAC="); if (skb->dev && skb->dev->hard_header_len && skb->mac.raw != (void*)skb->nh.iph) { int i; unsigned char *p = skb->mac.raw; for (i = 0; i < skb->dev->hard_header_len; i++,p++) printk("%02x%c", *p, i==skb->dev->hard_header_len - 1 ? ' ':':'); } else printk(" "); } dump_packet(loginfo, skb, 0); printk("\n"); spin_unlock_bh(&log_lock); } static unsigned int ipt_log_target(struct sk_buff **pskb, const struct net_device *in, const struct net_device *out, unsigned int hooknum, const void *targinfo, void *userinfo) { const struct ipt_log_info *loginfo = targinfo; char level_string[4] = "< >"; level_string[1] = '0' + (loginfo->level % 8); ipt_log_packet(hooknum, *pskb, in, out, loginfo, level_string, NULL); return IPT_CONTINUE; } static void ipt_logfn(unsigned int hooknum, const struct sk_buff *skb, const struct net_device *in, const struct net_device *out, const char *prefix) { struct ipt_log_info loginfo = { .level = 0, .logflags = IPT_LOG_MASK, .prefix = "" }; ipt_log_packet(hooknum, skb, in, out, &loginfo, KERN_WARNING, prefix); } static int ipt_log_checkentry(const char *tablename, const struct ipt_entry *e, void *targinfo, unsigned int targinfosize, unsigned int hook_mask) { const struct ipt_log_info *loginfo = targinfo; if (targinfosize != IPT_ALIGN(sizeof(struct ipt_log_info))) { DEBUGP("LOG: targinfosize %u != %u\n", targinfosize, IPT_ALIGN(sizeof(struct ipt_log_info))); return 0; } if (loginfo->level >= 8) { DEBUGP("LOG: level %u >= 8\n", loginfo->level); return 0; } if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') { DEBUGP("LOG: prefix term %i\n", loginfo->prefix[sizeof(loginfo->prefix)-1]); return 0; } return 1; } static struct ipt_target ipt_log_reg = { .name = "LOG", .target = ipt_log_target, .checkentry = ipt_log_checkentry, .me = THIS_MODULE, }; static int __init init(void) { if (ipt_register_target(&ipt_log_reg)) return -EINVAL; if (nflog) nf_log_register(PF_INET, &ipt_logfn); return 0; } static void __exit fini(void) { if (nflog) nf_log_unregister(PF_INET, &ipt_logfn); ipt_unregister_target(&ipt_log_reg); } module_init(init); module_exit(fini);