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|
// SPDX-License-Identifier: GPL-2.0-only
/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/skbuff.h>
#include <linux/if_arp.h>
#include <linux/ip.h>
#include <net/ipv6.h>
#include <net/icmp.h>
#include <net/udp.h>
#include <net/tcp.h>
#include <net/route.h>
#include <linux/netfilter.h>
#include <linux/netfilter/xt_LOG.h>
#include <net/netfilter/nf_log.h>
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 MACPROTO=%04x ",
eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
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 <coreteam@netfilter.org>");
MODULE_DESCRIPTION("Netfilter IPv4 packet logging");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NF_LOGGER(AF_INET, 0);
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