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
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
|
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
*/
#include "includes.h"
RCSID("$OpenBSD: auth-options.c,v 1.12 2001/02/03 10:08:36 markus Exp $");
#include "packet.h"
#include "xmalloc.h"
#include "match.h"
#include "log.h"
#include "canohost.h"
#include "auth-options.h"
#include "servconf.h"
/* Flags set authorized_keys flags */
int no_port_forwarding_flag = 0;
int no_agent_forwarding_flag = 0;
int no_x11_forwarding_flag = 0;
int no_pty_flag = 0;
/* "command=" option. */
char *forced_command = NULL;
/* "environment=" options. */
struct envstring *custom_environment = NULL;
extern ServerOptions options;
void
auth_clear_options(void)
{
no_agent_forwarding_flag = 0;
no_port_forwarding_flag = 0;
no_pty_flag = 0;
no_x11_forwarding_flag = 0;
while (custom_environment) {
struct envstring *ce = custom_environment;
custom_environment = ce->next;
xfree(ce->s);
xfree(ce);
}
if (forced_command) {
xfree(forced_command);
forced_command = NULL;
}
}
/*
* return 1 if access is granted, 0 if not.
* side effect: sets key option flags
*/
int
auth_parse_options(struct passwd *pw, char *opts, char *file, u_long linenum)
{
const char *cp;
if (!opts)
return 1;
/* reset options */
auth_clear_options();
while (*opts && *opts != ' ' && *opts != '\t') {
cp = "no-port-forwarding";
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
packet_send_debug("Port forwarding disabled.");
no_port_forwarding_flag = 1;
opts += strlen(cp);
goto next_option;
}
cp = "no-agent-forwarding";
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
packet_send_debug("Agent forwarding disabled.");
no_agent_forwarding_flag = 1;
opts += strlen(cp);
goto next_option;
}
cp = "no-X11-forwarding";
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
packet_send_debug("X11 forwarding disabled.");
no_x11_forwarding_flag = 1;
opts += strlen(cp);
goto next_option;
}
cp = "no-pty";
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
packet_send_debug("Pty allocation disabled.");
no_pty_flag = 1;
opts += strlen(cp);
goto next_option;
}
cp = "command=\"";
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
int i;
opts += strlen(cp);
forced_command = xmalloc(strlen(opts) + 1);
i = 0;
while (*opts) {
if (*opts == '"')
break;
if (*opts == '\\' && opts[1] == '"') {
opts += 2;
forced_command[i++] = '"';
continue;
}
forced_command[i++] = *opts++;
}
if (!*opts) {
debug("%.100s, line %lu: missing end quote",
file, linenum);
packet_send_debug("%.100s, line %lu: missing end quote",
file, linenum);
continue;
}
forced_command[i] = 0;
packet_send_debug("Forced command: %.900s", forced_command);
opts++;
goto next_option;
}
cp = "environment=\"";
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
int i;
char *s;
struct envstring *new_envstring;
opts += strlen(cp);
s = xmalloc(strlen(opts) + 1);
i = 0;
while (*opts) {
if (*opts == '"')
break;
if (*opts == '\\' && opts[1] == '"') {
opts += 2;
s[i++] = '"';
continue;
}
s[i++] = *opts++;
}
if (!*opts) {
debug("%.100s, line %lu: missing end quote",
file, linenum);
packet_send_debug("%.100s, line %lu: missing end quote",
file, linenum);
continue;
}
s[i] = 0;
packet_send_debug("Adding to environment: %.900s", s);
debug("Adding to environment: %.900s", s);
opts++;
new_envstring = xmalloc(sizeof(struct envstring));
new_envstring->s = s;
new_envstring->next = custom_environment;
custom_environment = new_envstring;
goto next_option;
}
cp = "from=\"";
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
int mname, mip;
const char *remote_ip = get_remote_ipaddr();
const char *remote_host = get_canonical_hostname(
options.reverse_mapping_check);
char *patterns = xmalloc(strlen(opts) + 1);
int i;
opts += strlen(cp);
i = 0;
while (*opts) {
if (*opts == '"')
break;
if (*opts == '\\' && opts[1] == '"') {
opts += 2;
patterns[i++] = '"';
continue;
}
patterns[i++] = *opts++;
}
if (!*opts) {
debug("%.100s, line %lu: missing end quote",
file, linenum);
packet_send_debug("%.100s, line %lu: missing end quote",
file, linenum);
continue;
}
patterns[i] = 0;
opts++;
/*
* Deny access if we get a negative
* match for the hostname or the ip
* or if we get not match at all
*/
mname = match_hostname(remote_host, patterns,
strlen(patterns));
mip = match_hostname(remote_ip, patterns,
strlen(patterns));
xfree(patterns);
if (mname == -1 || mip == -1 ||
(mname != 1 && mip != 1)) {
log("Authentication tried for %.100s with "
"correct key but not from a permitted "
"host (host=%.200s, ip=%.200s).",
pw->pw_name, remote_host, remote_ip);
packet_send_debug("Your host '%.200s' is not "
"permitted to use this key for login.",
remote_host);
/* deny access */
return 0;
}
/* Host name matches. */
goto next_option;
}
next_option:
/*
* Skip the comma, and move to the next option
* (or break out if there are no more).
*/
if (!*opts)
fatal("Bugs in auth-options.c option processing.");
if (*opts == ' ' || *opts == '\t')
break; /* End of options. */
if (*opts != ',')
goto bad_option;
opts++;
/* Process the next option. */
}
/* grant access */
return 1;
bad_option:
log("Bad options in %.100s file, line %lu: %.50s",
file, linenum, opts);
packet_send_debug("Bad options in %.100s file, line %lu: %.50s",
file, linenum, opts);
/* deny access */
return 0;
}
|
