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
162
163
164
165
|
// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#include <linux/audit.h>
#include <linux/netlink.h>
static int fd;
#define MAX_AUDIT_MESSAGE_LENGTH 8970
struct audit_message {
struct nlmsghdr nlh;
union {
struct audit_status s;
char data[MAX_AUDIT_MESSAGE_LENGTH];
} u;
};
int audit_recv(int fd, struct audit_message *rep)
{
struct sockaddr_nl addr;
socklen_t addrlen = sizeof(addr);
int ret;
do {
ret = recvfrom(fd, rep, sizeof(*rep), 0,
(struct sockaddr *)&addr, &addrlen);
} while (ret < 0 && errno == EINTR);
if (ret < 0 ||
addrlen != sizeof(addr) ||
addr.nl_pid != 0 ||
rep->nlh.nlmsg_type == NLMSG_ERROR) /* short-cut for now */
return -1;
return ret;
}
int audit_send(int fd, uint16_t type, uint32_t key, uint32_t val)
{
static int seq = 0;
struct audit_message msg = {
.nlh = {
.nlmsg_len = NLMSG_SPACE(sizeof(msg.u.s)),
.nlmsg_type = type,
.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK,
.nlmsg_seq = ++seq,
},
.u.s = {
.mask = key,
.enabled = key == AUDIT_STATUS_ENABLED ? val : 0,
.pid = key == AUDIT_STATUS_PID ? val : 0,
}
};
struct sockaddr_nl addr = {
.nl_family = AF_NETLINK,
};
int ret;
do {
ret = sendto(fd, &msg, msg.nlh.nlmsg_len, 0,
(struct sockaddr *)&addr, sizeof(addr));
} while (ret < 0 && errno == EINTR);
if (ret != (int)msg.nlh.nlmsg_len)
return -1;
return 0;
}
int audit_set(int fd, uint32_t key, uint32_t val)
{
struct audit_message rep = { 0 };
int ret;
ret = audit_send(fd, AUDIT_SET, key, val);
if (ret)
return ret;
ret = audit_recv(fd, &rep);
if (ret < 0)
return ret;
return 0;
}
int readlog(int fd)
{
struct audit_message rep = { 0 };
int ret = audit_recv(fd, &rep);
const char *sep = "";
char *k, *v;
if (ret < 0)
return ret;
if (rep.nlh.nlmsg_type != AUDIT_NETFILTER_CFG)
return 0;
/* skip the initial "audit(...): " part */
strtok(rep.u.data, " ");
while ((k = strtok(NULL, "="))) {
v = strtok(NULL, " ");
/* these vary and/or are uninteresting, ignore */
if (!strcmp(k, "pid") ||
!strcmp(k, "comm") ||
!strcmp(k, "subj"))
continue;
/* strip the varying sequence number */
if (!strcmp(k, "table"))
*strchrnul(v, ':') = '\0';
printf("%s%s=%s", sep, k, v);
sep = " ";
}
if (*sep) {
printf("\n");
fflush(stdout);
}
return 0;
}
void cleanup(int sig)
{
audit_set(fd, AUDIT_STATUS_ENABLED, 0);
close(fd);
if (sig)
exit(0);
}
int main(int argc, char **argv)
{
struct sigaction act = {
.sa_handler = cleanup,
};
fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_AUDIT);
if (fd < 0) {
perror("Can't open netlink socket");
return -1;
}
if (sigaction(SIGTERM, &act, NULL) < 0 ||
sigaction(SIGINT, &act, NULL) < 0) {
perror("Can't set signal handler");
close(fd);
return -1;
}
audit_set(fd, AUDIT_STATUS_ENABLED, 1);
audit_set(fd, AUDIT_STATUS_PID, getpid());
while (1)
readlog(fd);
}
|
