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12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/audit.h>
15#include <linux/module.h>
16#include <linux/skbuff.h>
17#include <linux/tcp.h>
18#include <linux/udp.h>
19#include <linux/if_arp.h>
20#include <linux/netfilter/x_tables.h>
21#include <linux/netfilter/xt_AUDIT.h>
22#include <linux/netfilter_bridge/ebtables.h>
23#include <net/ipv6.h>
24#include <net/ip.h>
25
26MODULE_LICENSE("GPL");
27MODULE_AUTHOR("Thomas Graf <tgraf@redhat.com>");
28MODULE_DESCRIPTION("Xtables: creates audit records for dropped/accepted packets");
29MODULE_ALIAS("ipt_AUDIT");
30MODULE_ALIAS("ip6t_AUDIT");
31MODULE_ALIAS("ebt_AUDIT");
32MODULE_ALIAS("arpt_AUDIT");
33
34static void audit_proto(struct audit_buffer *ab, struct sk_buff *skb,
35 unsigned int proto, unsigned int offset)
36{
37 switch (proto) {
38 case IPPROTO_TCP:
39 case IPPROTO_UDP:
40 case IPPROTO_UDPLITE: {
41 const __be16 *pptr;
42 __be16 _ports[2];
43
44 pptr = skb_header_pointer(skb, offset, sizeof(_ports), _ports);
45 if (pptr == NULL) {
46 audit_log_format(ab, " truncated=1");
47 return;
48 }
49
50 audit_log_format(ab, " sport=%hu dport=%hu",
51 ntohs(pptr[0]), ntohs(pptr[1]));
52 }
53 break;
54
55 case IPPROTO_ICMP:
56 case IPPROTO_ICMPV6: {
57 const u8 *iptr;
58 u8 _ih[2];
59
60 iptr = skb_header_pointer(skb, offset, sizeof(_ih), &_ih);
61 if (iptr == NULL) {
62 audit_log_format(ab, " truncated=1");
63 return;
64 }
65
66 audit_log_format(ab, " icmptype=%hhu icmpcode=%hhu",
67 iptr[0], iptr[1]);
68
69 }
70 break;
71 }
72}
73
74static void audit_ip4(struct audit_buffer *ab, struct sk_buff *skb)
75{
76 struct iphdr _iph;
77 const struct iphdr *ih;
78
79 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
80 if (!ih) {
81 audit_log_format(ab, " truncated=1");
82 return;
83 }
84
85 audit_log_format(ab, " saddr=%pI4 daddr=%pI4 ipid=%hu proto=%hhu",
86 &ih->saddr, &ih->daddr, ntohs(ih->id), ih->protocol);
87
88 if (ntohs(ih->frag_off) & IP_OFFSET) {
89 audit_log_format(ab, " frag=1");
90 return;
91 }
92
93 audit_proto(ab, skb, ih->protocol, ih->ihl * 4);
94}
95
96static void audit_ip6(struct audit_buffer *ab, struct sk_buff *skb)
97{
98 struct ipv6hdr _ip6h;
99 const struct ipv6hdr *ih;
100 u8 nexthdr;
101 __be16 frag_off;
102 int offset;
103
104 ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_ip6h), &_ip6h);
105 if (!ih) {
106 audit_log_format(ab, " truncated=1");
107 return;
108 }
109
110 nexthdr = ih->nexthdr;
111 offset = ipv6_skip_exthdr(skb, skb_network_offset(skb) + sizeof(_ip6h),
112 &nexthdr, &frag_off);
113
114 audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu",
115 &ih->saddr, &ih->daddr, nexthdr);
116
117 if (offset)
118 audit_proto(ab, skb, nexthdr, offset);
119}
120
121static unsigned int
122audit_tg(struct sk_buff *skb, const struct xt_action_param *par)
123{
124 const struct xt_audit_info *info = par->targinfo;
125 struct audit_buffer *ab;
126
127 if (audit_enabled == 0)
128 goto errout;
129
130 ab = audit_log_start(NULL, GFP_ATOMIC, AUDIT_NETFILTER_PKT);
131 if (ab == NULL)
132 goto errout;
133
134 audit_log_format(ab, "action=%hhu hook=%u len=%u inif=%s outif=%s",
135 info->type, par->hooknum, skb->len,
136 par->in ? par->in->name : "?",
137 par->out ? par->out->name : "?");
138
139 if (skb->mark)
140 audit_log_format(ab, " mark=%#x", skb->mark);
141
142 if (skb->dev && skb->dev->type == ARPHRD_ETHER) {
143 audit_log_format(ab, " smac=%pM dmac=%pM macproto=0x%04x",
144 eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
145 ntohs(eth_hdr(skb)->h_proto));
146
147 if (par->family == NFPROTO_BRIDGE) {
148 switch (eth_hdr(skb)->h_proto) {
149 case __constant_htons(ETH_P_IP):
150 audit_ip4(ab, skb);
151 break;
152
153 case __constant_htons(ETH_P_IPV6):
154 audit_ip6(ab, skb);
155 break;
156 }
157 }
158 }
159
160 switch (par->family) {
161 case NFPROTO_IPV4:
162 audit_ip4(ab, skb);
163 break;
164
165 case NFPROTO_IPV6:
166 audit_ip6(ab, skb);
167 break;
168 }
169
170#ifdef CONFIG_NETWORK_SECMARK
171 if (skb->secmark)
172 audit_log_secctx(ab, skb->secmark);
173#endif
174
175 audit_log_end(ab);
176
177errout:
178 return XT_CONTINUE;
179}
180
181static unsigned int
182audit_tg_ebt(struct sk_buff *skb, const struct xt_action_param *par)
183{
184 audit_tg(skb, par);
185 return EBT_CONTINUE;
186}
187
188static int audit_tg_check(const struct xt_tgchk_param *par)
189{
190 const struct xt_audit_info *info = par->targinfo;
191
192 if (info->type > XT_AUDIT_TYPE_MAX) {
193 pr_info("Audit type out of range (valid range: 0..%hhu)\n",
194 XT_AUDIT_TYPE_MAX);
195 return -ERANGE;
196 }
197
198 return 0;
199}
200
201static struct xt_target audit_tg_reg[] __read_mostly = {
202 {
203 .name = "AUDIT",
204 .family = NFPROTO_UNSPEC,
205 .target = audit_tg,
206 .targetsize = sizeof(struct xt_audit_info),
207 .checkentry = audit_tg_check,
208 .me = THIS_MODULE,
209 },
210 {
211 .name = "AUDIT",
212 .family = NFPROTO_BRIDGE,
213 .target = audit_tg_ebt,
214 .targetsize = sizeof(struct xt_audit_info),
215 .checkentry = audit_tg_check,
216 .me = THIS_MODULE,
217 },
218};
219
220static int __init audit_tg_init(void)
221{
222 return xt_register_targets(audit_tg_reg, ARRAY_SIZE(audit_tg_reg));
223}
224
225static void __exit audit_tg_exit(void)
226{
227 xt_unregister_targets(audit_tg_reg, ARRAY_SIZE(audit_tg_reg));
228}
229
230module_init(audit_tg_init);
231module_exit(audit_tg_exit);
232
