aboutsummaryrefslogtreecommitdiffstats
path: root/net/ipv4/netfilter/ipt_LOG.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/ipv4/netfilter/ipt_LOG.c')
-rw-r--r--net/ipv4/netfilter/ipt_LOG.c516
1 files changed, 516 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ipt_LOG.c b/net/ipv4/netfilter/ipt_LOG.c
new file mode 100644
index 00000000..d76d6c9e
--- /dev/null
+++ b/net/ipv4/netfilter/ipt_LOG.c
@@ -0,0 +1,516 @@
+/*
+ * This is a module which is used for logging packets.
+ */
+
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
+ *
+ * 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.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/skbuff.h>
+#include <linux/if_arp.h>
+#include <linux/ip.h>
+#include <net/icmp.h>
+#include <net/udp.h>
+#include <net/tcp.h>
+#include <net/route.h>
+
+#include <linux/netfilter.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter_ipv4/ipt_LOG.h>
+#include <net/netfilter/nf_log.h>
+#include <net/netfilter/xt_log.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
+MODULE_DESCRIPTION("Xtables: IPv4 packet logging to syslog");
+
+/* One level of recursion won't kill us */
+static void dump_packet(struct sbuff *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_MASK;
+
+ ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph);
+ if (ih == NULL) {
+ sb_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 " */
+ sb_add(m, "SRC=%pI4 DST=%pI4 ",
+ &ih->saddr, &ih->daddr);
+
+ /* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */
+ sb_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)
+ sb_add(m, "CE ");
+ if (ntohs(ih->frag_off) & IP_DF)
+ sb_add(m, "DF ");
+ if (ntohs(ih->frag_off) & IP_MF)
+ sb_add(m, "MF ");
+
+ /* Max length: 11 "FRAG:65535 " */
+ if (ntohs(ih->frag_off) & IP_OFFSET)
+ sb_add(m, "FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET);
+
+ if ((logflags & IPT_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) {
+ sb_add(m, "TRUNCATED");
+ return;
+ }
+
+ /* Max length: 127 "OPT (" 15*4*2chars ") " */
+ sb_add(m, "OPT (");
+ for (i = 0; i < optsize; i++)
+ sb_add(m, "%02X", op[i]);
+ sb_add(m, ") ");
+ }
+
+ switch (ih->protocol) {
+ case IPPROTO_TCP: {
+ struct tcphdr _tcph;
+ const struct tcphdr *th;
+
+ /* Max length: 10 "PROTO=TCP " */
+ sb_add(m, "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) {
+ sb_add(m, "INCOMPLETE [%u bytes] ",
+ skb->len - iphoff - ih->ihl*4);
+ break;
+ }
+
+ /* Max length: 20 "SPT=65535 DPT=65535 " */
+ sb_add(m, "SPT=%u DPT=%u ",
+ ntohs(th->source), ntohs(th->dest));
+ /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
+ if (logflags & IPT_LOG_TCPSEQ)
+ sb_add(m, "SEQ=%u ACK=%u ",
+ ntohl(th->seq), ntohl(th->ack_seq));
+ /* Max length: 13 "WINDOW=65535 " */
+ sb_add(m, "WINDOW=%u ", ntohs(th->window));
+ /* Max length: 9 "RES=0x3F " */
+ sb_add(m, "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)
+ sb_add(m, "CWR ");
+ if (th->ece)
+ sb_add(m, "ECE ");
+ if (th->urg)
+ sb_add(m, "URG ");
+ if (th->ack)
+ sb_add(m, "ACK ");
+ if (th->psh)
+ sb_add(m, "PSH ");
+ if (th->rst)
+ sb_add(m, "RST ");
+ if (th->syn)
+ sb_add(m, "SYN ");
+ if (th->fin)
+ sb_add(m, "FIN ");
+ /* Max length: 11 "URGP=65535 " */
+ sb_add(m, "URGP=%u ", ntohs(th->urg_ptr));
+
+ if ((logflags & IPT_LOG_TCPOPT) &&
+ th->doff * 4 > sizeof(struct tcphdr)) {
+ unsigned char _opt[4 * 15 - sizeof(struct tcphdr)];
+ const 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) {
+ sb_add(m, "TRUNCATED");
+ return;
+ }
+
+ /* Max length: 127 "OPT (" 15*4*2chars ") " */
+ sb_add(m, "OPT (");
+ for (i = 0; i < optsize; i++)
+ sb_add(m, "%02X", op[i]);
+ sb_add(m, ") ");
+ }
+ break;
+ }
+ case IPPROTO_UDP:
+ case IPPROTO_UDPLITE: {
+ struct udphdr _udph;
+ const struct udphdr *uh;
+
+ if (ih->protocol == IPPROTO_UDP)
+ /* Max length: 10 "PROTO=UDP " */
+ sb_add(m, "PROTO=UDP " );
+ else /* Max length: 14 "PROTO=UDPLITE " */
+ sb_add(m, "PROTO=UDPLITE ");
+
+ 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) {
+ sb_add(m, "INCOMPLETE [%u bytes] ",
+ skb->len - iphoff - ih->ihl*4);
+ break;
+ }
+
+ /* Max length: 20 "SPT=65535 DPT=65535 " */
+ sb_add(m, "SPT=%u DPT=%u LEN=%u ",
+ ntohs(uh->source), ntohs(uh->dest),
+ ntohs(uh->len));
+ 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 " */
+ sb_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) {
+ sb_add(m, "INCOMPLETE [%u bytes] ",
+ skb->len - iphoff - ih->ihl*4);
+ break;
+ }
+
+ /* Max length: 18 "TYPE=255 CODE=255 " */
+ sb_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]) {
+ sb_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 " */
+ sb_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 " */
+ sb_add(m, "PARAMETER=%u ",
+ ntohl(ich->un.gateway) >> 24);
+ break;
+ case ICMP_REDIRECT:
+ /* Max length: 24 "GATEWAY=255.255.255.255 " */
+ sb_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. */
+ sb_add(m, "[");
+ dump_packet(m, info, skb,
+ iphoff + ih->ihl*4+sizeof(_icmph));
+ sb_add(m, "] ");
+ }
+
+ /* Max length: 10 "MTU=65535 " */
+ if (ich->type == ICMP_DEST_UNREACH &&
+ ich->code == ICMP_FRAG_NEEDED)
+ sb_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 " */
+ sb_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) {
+ sb_add(m, "INCOMPLETE [%u bytes] ",
+ skb->len - iphoff - ih->ihl*4);
+ break;
+ }
+
+ /* Length: 15 "SPI=0xF1234567 " */
+ sb_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 " */
+ sb_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) {
+ sb_add(m, "INCOMPLETE [%u bytes] ",
+ skb->len - iphoff - ih->ihl*4);
+ break;
+ }
+
+ /* Length: 15 "SPI=0xF1234567 " */
+ sb_add(m, "SPI=0x%x ", ntohl(eh->spi));
+ break;
+ }
+ /* Max length: 10 "PROTO 255 " */
+ default:
+ sb_add(m, "PROTO=%u ", ih->protocol);
+ }
+
+ /* Max length: 15 "UID=4294967295 " */
+ if ((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)
+ sb_add(m, "UID=%u GID=%u ",
+ skb->sk->sk_socket->file->f_cred->fsuid,
+ skb->sk->sk_socket->file->f_cred->fsgid);
+ read_unlock_bh(&skb->sk->sk_callback_lock);
+ }
+
+ /* Max length: 16 "MARK=0xFFFFFFFF " */
+ if (!iphoff && skb->mark)
+ sb_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_mac_header(struct sbuff *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 & IPT_LOG_MACDECODE))
+ goto fallback;
+
+ switch (dev->type) {
+ case ARPHRD_ETHER:
+ sb_add(m, "MACSRC=%pM MACDST=%pM MACPROTO=%04x ",
+ eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
+ ntohs(eth_hdr(skb)->h_proto));
+ return;
+ default:
+ break;
+ }
+
+fallback:
+ sb_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;
+
+ sb_add(m, "%02x", *p++);
+ for (i = 1; i < dev->hard_header_len; i++, p++)
+ sb_add(m, ":%02x", *p);
+ }
+ sb_add(m, " ");
+}
+
+static struct nf_loginfo default_loginfo = {
+ .type = NF_LOG_TYPE_LOG,
+ .u = {
+ .log = {
+ .level = 5,
+ .logflags = NF_LOG_MASK,
+ },
+ },
+};
+
+static void
+ipt_log_packet(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 sbuff *m = sb_open();
+
+ if (!loginfo)
+ loginfo = &default_loginfo;
+
+ sb_add(m, "<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
+ prefix,
+ in ? in->name : "",
+ out ? out->name : "");
+#ifdef CONFIG_BRIDGE_NETFILTER
+ if (skb->nf_bridge) {
+ const struct net_device *physindev;
+ const struct net_device *physoutdev;
+
+ physindev = skb->nf_bridge->physindev;
+ if (physindev && in != physindev)
+ sb_add(m, "PHYSIN=%s ", physindev->name);
+ physoutdev = skb->nf_bridge->physoutdev;
+ if (physoutdev && out != physoutdev)
+ sb_add(m, "PHYSOUT=%s ", physoutdev->name);
+ }
+#endif
+
+ if (in != NULL)
+ dump_mac_header(m, loginfo, skb);
+
+ dump_packet(m, loginfo, skb, 0);
+
+ sb_close(m);
+}
+
+static unsigned int
+log_tg(struct sk_buff *skb, const struct xt_action_param *par)
+{
+ const struct ipt_log_info *loginfo = par->targinfo;
+ struct nf_loginfo li;
+
+ li.type = NF_LOG_TYPE_LOG;
+ li.u.log.level = loginfo->level;
+ li.u.log.logflags = loginfo->logflags;
+
+ ipt_log_packet(NFPROTO_IPV4, par->hooknum, skb, par->in, par->out, &li,
+ loginfo->prefix);
+ return XT_CONTINUE;
+}
+
+static int log_tg_check(const struct xt_tgchk_param *par)
+{
+ const struct ipt_log_info *loginfo = par->targinfo;
+
+ if (loginfo->level >= 8) {
+ pr_debug("level %u >= 8\n", loginfo->level);
+ return -EINVAL;
+ }
+ if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
+ pr_debug("prefix is not null-terminated\n");
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static struct xt_target log_tg_reg __read_mostly = {
+ .name = "LOG",
+ .family = NFPROTO_IPV4,
+ .target = log_tg,
+ .targetsize = sizeof(struct ipt_log_info),
+ .checkentry = log_tg_check,
+ .me = THIS_MODULE,
+};
+
+static struct nf_logger ipt_log_logger __read_mostly = {
+ .name = "ipt_LOG",
+ .logfn = &ipt_log_packet,
+ .me = THIS_MODULE,
+};
+
+static int __init log_tg_init(void)
+{
+ int ret;
+
+ ret = xt_register_target(&log_tg_reg);
+ if (ret < 0)
+ return ret;
+ nf_log_register(NFPROTO_IPV4, &ipt_log_logger);
+ return 0;
+}
+
+static void __exit log_tg_exit(void)
+{
+ nf_log_unregister(&ipt_log_logger);
+ xt_unregister_target(&log_tg_reg);
+}
+
+module_init(log_tg_init);
+module_exit(log_tg_exit);
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-06 20:09:49 +0000