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11
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 bool audit_ip4(struct audit_buffer *ab, struct sk_buff *skb)
35{
36 struct iphdr _iph;
37 const struct iphdr *ih;
38
39 ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_iph), &_iph);
40 if (!ih)
41 return false;
42
43 audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu",
44 &ih->saddr, &ih->daddr, ih->protocol);
45
46 return true;
47}
48
49static bool audit_ip6(struct audit_buffer *ab, struct sk_buff *skb)
50{
51 struct ipv6hdr _ip6h;
52 const struct ipv6hdr *ih;
53 u8 nexthdr;
54 __be16 frag_off;
55
56 ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_ip6h), &_ip6h);
57 if (!ih)
58 return false;
59
60 nexthdr = ih->nexthdr;
61 ipv6_skip_exthdr(skb, skb_network_offset(skb) + sizeof(_ip6h), &nexthdr, &frag_off);
62
63 audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu",
64 &ih->saddr, &ih->daddr, nexthdr);
65
66 return true;
67}
68
69static unsigned int
70audit_tg(struct sk_buff *skb, const struct xt_action_param *par)
71{
72 struct audit_buffer *ab;
73 int fam = -1;
74
75 if (audit_enabled == 0)
76 goto errout;
77 ab = audit_log_start(NULL, GFP_ATOMIC, AUDIT_NETFILTER_PKT);
78 if (ab == NULL)
79 goto errout;
80
81 audit_log_format(ab, "mark=%#x", skb->mark);
82
83 switch (xt_family(par)) {
84 case NFPROTO_BRIDGE:
85 switch (eth_hdr(skb)->h_proto) {
86 case htons(ETH_P_IP):
87 fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
88 break;
89 case htons(ETH_P_IPV6):
90 fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
91 break;
92 }
93 break;
94 case NFPROTO_IPV4:
95 fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
96 break;
97 case NFPROTO_IPV6:
98 fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
99 break;
100 }
101
102 if (fam == -1)
103 audit_log_format(ab, " saddr=? daddr=? proto=-1");
104
105 audit_log_end(ab);
106
107errout:
108 return XT_CONTINUE;
109}
110
111static unsigned int
112audit_tg_ebt(struct sk_buff *skb, const struct xt_action_param *par)
113{
114 audit_tg(skb, par);
115 return EBT_CONTINUE;
116}
117
118static int audit_tg_check(const struct xt_tgchk_param *par)
119{
120 const struct xt_audit_info *info = par->targinfo;
121
122 if (info->type > XT_AUDIT_TYPE_MAX) {
123 pr_info_ratelimited("Audit type out of range (valid range: 0..%hhu)\n",
124 XT_AUDIT_TYPE_MAX);
125 return -ERANGE;
126 }
127
128 return 0;
129}
130
131static struct xt_target audit_tg_reg[] __read_mostly = {
132 {
133 .name = "AUDIT",
134 .family = NFPROTO_UNSPEC,
135 .target = audit_tg,
136 .targetsize = sizeof(struct xt_audit_info),
137 .checkentry = audit_tg_check,
138 .me = THIS_MODULE,
139 },
140 {
141 .name = "AUDIT",
142 .family = NFPROTO_BRIDGE,
143 .target = audit_tg_ebt,
144 .targetsize = sizeof(struct xt_audit_info),
145 .checkentry = audit_tg_check,
146 .me = THIS_MODULE,
147 },
148};
149
150static int __init audit_tg_init(void)
151{
152 return xt_register_targets(audit_tg_reg, ARRAY_SIZE(audit_tg_reg));
153}
154
155static void __exit audit_tg_exit(void)
156{
157 xt_unregister_targets(audit_tg_reg, ARRAY_SIZE(audit_tg_reg));
158}
159
160module_init(audit_tg_init);
161module_exit(audit_tg_exit);
162
