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
|
/* $Id: port-linux.c,v 1.3 2006/09/01 05:38:41 djm Exp $ */
/*
* Copyright (c) 2005 Daniel Walsh <dwalsh@redhat.com>
* Copyright (c) 2006 Damien Miller <djm@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 USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* Linux-specific portability code - just SELinux support at present
*/
#include "includes.h"
#include <errno.h>
#include <stdarg.h>
#include <string.h>
#ifdef WITH_SELINUX
#include "log.h"
#include "port-linux.h"
#include <selinux/selinux.h>
#include <selinux/flask.h>
#include <selinux/get_context_list.h>
/* Wrapper around is_selinux_enabled() to log its return value once only */
static int
ssh_selinux_enabled(void)
{
static int enabled = -1;
if (enabled == -1) {
enabled = is_selinux_enabled();
debug("SELinux support %s", enabled ? "enabled" : "disabled");
}
return (enabled);
}
/* Return the default security context for the given username */
static security_context_t
ssh_selinux_getctxbyname(char *pwname)
{
security_context_t sc;
char *sename = NULL, *lvl = NULL;
int r;
#ifdef HAVE_GETSEUSERBYNAME
if (getseuserbyname(pwname, &sename, &lvl) != 0)
return NULL;
#else
sename = pwname;
lvl = NULL;
#endif
#ifdef HAVE_GET_DEFAULT_CONTEXT_WITH_LEVEL
r = get_default_context_with_level(sename, lvl, NULL, &sc);
#else
r = get_default_context(sename, NULL, &sc);
#endif
if (r != 0) {
switch (security_getenforce()) {
case -1:
fatal("%s: ssh_selinux_getctxbyname: "
"security_getenforce() failed", __func__);
case 0:
error("%s: Failed to get default SELinux security "
"context for %s", __func__, pwname);
default:
fatal("%s: Failed to get default SELinux security "
"context for %s (in enforcing mode)",
__func__, pwname);
}
}
#ifdef HAVE_GETSEUSERBYNAME
if (sename != NULL)
xfree(sename);
if (lvl != NULL)
xfree(lvl);
#endif
return (sc);
}
/* Set the execution context to the default for the specified user */
void
ssh_selinux_setup_exec_context(char *pwname)
{
security_context_t user_ctx = NULL;
if (!ssh_selinux_enabled())
return;
debug3("%s: setting execution context", __func__);
user_ctx = ssh_selinux_getctxbyname(pwname);
if (setexeccon(user_ctx) != 0) {
switch (security_getenforce()) {
case -1:
fatal("%s: security_getenforce() failed", __func__);
case 0:
error("%s: Failed to set SELinux execution "
"context for %s", __func__, pwname);
default:
fatal("%s: Failed to set SELinux execution context "
"for %s (in enforcing mode)", __func__, pwname);
}
}
if (user_ctx != NULL)
freecon(user_ctx);
debug3("%s: done", __func__);
}
/* Set the TTY context for the specified user */
void
ssh_selinux_setup_pty(char *pwname, const char *tty)
{
security_context_t new_tty_ctx = NULL;
security_context_t user_ctx = NULL;
security_context_t old_tty_ctx = NULL;
if (!ssh_selinux_enabled())
return;
debug3("%s: setting TTY context on %s", __func__, tty);
user_ctx = ssh_selinux_getctxbyname(pwname);
/* XXX: should these calls fatal() upon failure in enforcing mode? */
if (getfilecon(tty, &old_tty_ctx) == -1) {
error("%s: getfilecon: %s", __func__, strerror(errno));
goto out;
}
if (security_compute_relabel(user_ctx, old_tty_ctx,
SECCLASS_CHR_FILE, &new_tty_ctx) != 0) {
error("%s: security_compute_relabel: %s",
__func__, strerror(errno));
goto out;
}
if (setfilecon(tty, new_tty_ctx) != 0)
error("%s: setfilecon: %s", __func__, strerror(errno));
out:
if (new_tty_ctx != NULL)
freecon(new_tty_ctx);
if (old_tty_ctx != NULL)
freecon(old_tty_ctx);
if (user_ctx != NULL)
freecon(user_ctx);
debug3("%s: done", __func__);
}
#endif /* WITH_SELINUX */
|
