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
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
/* $OpenBSD: privsep.c,v 1.16 2011/04/04 11:14:52 krw Exp $ */
/*
* Copyright (c) 2004 Henning Brauer <henning@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER IN
* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
* OF OR IN CONNECTION WITH THE USE, ABUSE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "dhcpd.h"
#include "privsep.h"
struct buf *
buf_open(size_t len)
{
struct buf *buf;
if ((buf = calloc(1, sizeof(struct buf))) == NULL)
error("buf_open: %m");
if ((buf->buf = malloc(len)) == NULL) {
free(buf);
error("buf_open: %m");
}
buf->size = len;
return (buf);
}
void
buf_add(struct buf *buf, void *data, size_t len)
{
if (len == 0)
return;
if (buf->wpos + len > buf->size)
error("buf_add: %m");
memcpy(buf->buf + buf->wpos, data, len);
buf->wpos += len;
}
void
buf_close(int sock, struct buf *buf)
{
ssize_t n;
do {
n = write(sock, buf->buf + buf->rpos, buf->size - buf->rpos);
if (n == 0) /* connection closed */
error("buf_close (connection closed)");
if (n != -1 && n < buf->size - buf->rpos)
error("buf_close (short write): %m");
} while (n == -1 && (errno == EAGAIN || errno == EINTR));
if (n == -1)
error("buf_close: %m");
free(buf->buf);
free(buf);
}
void
buf_read(int sock, void *buf, size_t nbytes)
{
ssize_t n;
do {
n = read(sock, buf, nbytes);
if (n == 0) { /* connection closed */
#ifdef DEBUG
debug("buf_read (connection closed)");
#endif
exit(1);
}
if (n != -1 && n < nbytes)
error("buf_read (short read): %m");
} while (n == -1 && (errno == EINTR || errno == EAGAIN));
if (n == -1)
error("buf_read: %m");
}
void
dispatch_imsg(int fd)
{
struct imsg_hdr hdr;
char *reason, *filename,
*servername, *prefix;
size_t reason_len, filename_len,
servername_len, prefix_len, totlen;
struct client_lease lease;
int ret, i, optlen;
struct buf *buf;
buf_read(fd, &hdr, sizeof(hdr));
switch (hdr.code) {
case IMSG_SCRIPT_INIT:
if (hdr.len < sizeof(hdr) + sizeof(size_t))
error("corrupted message received");
buf_read(fd, &reason_len, sizeof(reason_len));
if (hdr.len < reason_len + sizeof(hdr) + sizeof(size_t) ||
reason_len == SIZE_T_MAX)
error("corrupted message received");
if (reason_len > 0) {
if ((reason = calloc(1, reason_len + 1)) == NULL)
error("%m");
buf_read(fd, reason, reason_len);
} else
reason = NULL;
priv_script_init(reason);
free(reason);
break;
case IMSG_SCRIPT_WRITE_PARAMS:
bzero(&lease, sizeof lease);
totlen = sizeof(hdr) + sizeof(lease) + sizeof(size_t);
if (hdr.len < totlen)
error("corrupted message received");
buf_read(fd, &lease, sizeof(lease));
buf_read(fd, &filename_len, sizeof(filename_len));
totlen += filename_len + sizeof(size_t);
if (hdr.len < totlen || filename_len == SIZE_T_MAX)
error("corrupted message received");
if (filename_len > 0) {
if ((filename = calloc(1, filename_len + 1)) == NULL)
error("%m");
buf_read(fd, filename, filename_len);
} else
filename = NULL;
buf_read(fd, &servername_len, sizeof(servername_len));
totlen += servername_len + sizeof(size_t);
if (hdr.len < totlen || servername_len == SIZE_T_MAX)
error("corrupted message received");
if (servername_len > 0) {
if ((servername =
calloc(1, servername_len + 1)) == NULL)
error("%m");
buf_read(fd, servername, servername_len);
} else
servername = NULL;
buf_read(fd, &prefix_len, sizeof(prefix_len));
totlen += prefix_len;
if (hdr.len < totlen || prefix_len == SIZE_T_MAX)
error("corrupted message received");
if (prefix_len > 0) {
if ((prefix = calloc(1, prefix_len + 1)) == NULL)
error("%m");
buf_read(fd, prefix, prefix_len);
} else
prefix = NULL;
for (i = 0; i < 256; i++) {
totlen += sizeof(optlen);
if (hdr.len < totlen)
error("corrupted message received");
buf_read(fd, &optlen, sizeof(optlen));
lease.options[i].data = NULL;
lease.options[i].len = optlen;
if (optlen > 0) {
totlen += optlen;
if (hdr.len < totlen || optlen == SIZE_T_MAX)
error("corrupted message received");
lease.options[i].data =
calloc(1, optlen + 1);
if (lease.options[i].data == NULL)
error("%m");
buf_read(fd, lease.options[i].data, optlen);
}
}
lease.server_name = servername;
lease.filename = filename;
priv_script_write_params(prefix, &lease);
free(servername);
free(filename);
free(prefix);
for (i = 0; i < 256; i++)
if (lease.options[i].len > 0)
free(lease.options[i].data);
break;
case IMSG_SCRIPT_GO:
if (hdr.len != sizeof(hdr))
error("corrupted message received");
ret = priv_script_go();
hdr.code = IMSG_SCRIPT_GO_RET;
hdr.len = sizeof(struct imsg_hdr) + sizeof(int);
if ((buf = buf_open(hdr.len)) == NULL)
error("buf_open: %m");
buf_add(buf, &hdr, sizeof(hdr));
buf_add(buf, &ret, sizeof(ret));
buf_close(fd, buf);
break;
default:
error("received unknown message, code %d", hdr.code);
}
}
|
