1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
|
/*
* Creates audit record for dropped/accepted packets
*
* (C) 2010-2011 Thomas Graf <tgraf@redhat.com>
* (C) 2010-2011 Red Hat, Inc.
*
* 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/audit.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/if_arp.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_AUDIT.h>
#include <linux/netfilter_bridge/ebtables.h>
#include <net/ipv6.h>
#include <net/ip.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Thomas Graf <tgraf@redhat.com>");
MODULE_DESCRIPTION("Xtables: creates audit records for dropped/accepted packets");
MODULE_ALIAS("ipt_AUDIT");
MODULE_ALIAS("ip6t_AUDIT");
MODULE_ALIAS("ebt_AUDIT");
MODULE_ALIAS("arpt_AUDIT");
static bool audit_ip4(struct audit_buffer *ab, struct sk_buff *skb)
{
struct iphdr _iph;
const struct iphdr *ih;
ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_iph), &_iph);
if (!ih)
return false;
audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu",
&ih->saddr, &ih->daddr, ih->protocol);
return true;
}
static bool audit_ip6(struct audit_buffer *ab, struct sk_buff *skb)
{
struct ipv6hdr _ip6h;
const struct ipv6hdr *ih;
u8 nexthdr;
__be16 frag_off;
ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_ip6h), &_ip6h);
if (!ih)
return false;
nexthdr = ih->nexthdr;
ipv6_skip_exthdr(skb, skb_network_offset(skb) + sizeof(_ip6h), &nexthdr, &frag_off);
audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu",
&ih->saddr, &ih->daddr, nexthdr);
return true;
}
static unsigned int
audit_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
struct audit_buffer *ab;
int fam = -1;
if (audit_enabled == 0)
goto errout;
ab = audit_log_start(NULL, GFP_ATOMIC, AUDIT_NETFILTER_PKT);
if (ab == NULL)
goto errout;
audit_log_format(ab, "mark=%#x", skb->mark);
switch (xt_family(par)) {
case NFPROTO_BRIDGE:
switch (eth_hdr(skb)->h_proto) {
case htons(ETH_P_IP):
fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
break;
case htons(ETH_P_IPV6):
fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
break;
}
break;
case NFPROTO_IPV4:
fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
break;
case NFPROTO_IPV6:
fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
break;
}
if (fam == -1)
audit_log_format(ab, " saddr=? daddr=? proto=-1");
audit_log_end(ab);
errout:
return XT_CONTINUE;
}
static unsigned int
audit_tg_ebt(struct sk_buff *skb, const struct xt_action_param *par)
{
audit_tg(skb, par);
return EBT_CONTINUE;
}
static int audit_tg_check(const struct xt_tgchk_param *par)
{
const struct xt_audit_info *info = par->targinfo;
if (info->type > XT_AUDIT_TYPE_MAX) {
pr_info_ratelimited("Audit type out of range (valid range: 0..%hhu)\n",
XT_AUDIT_TYPE_MAX);
return -ERANGE;
}
return 0;
}
static struct xt_target audit_tg_reg[] __read_mostly = {
{
.name = "AUDIT",
.family = NFPROTO_UNSPEC,
.target = audit_tg,
.targetsize = sizeof(struct xt_audit_info),
.checkentry = audit_tg_check,
.me = THIS_MODULE,
},
{
.name = "AUDIT",
.family = NFPROTO_BRIDGE,
.target = audit_tg_ebt,
.targetsize = sizeof(struct xt_audit_info),
.checkentry = audit_tg_check,
.me = THIS_MODULE,
},
};
static int __init audit_tg_init(void)
{
return xt_register_targets(audit_tg_reg, ARRAY_SIZE(audit_tg_reg));
}
static void __exit audit_tg_exit(void)
{
xt_unregister_targets(audit_tg_reg, ARRAY_SIZE(audit_tg_reg));
}
module_init(audit_tg_init);
module_exit(audit_tg_exit);
|
