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
|
/*
* This file and its contents are supplied under the terms of the
* Common Development and Distribution License ("CDDL"), version 1.0.
* You may only use this file in accordance with the terms of version
* 1.0 of the CDDL.
*
* A full copy of the text of the CDDL should have accompanied this
* source. A copy of the CDDL is also available via the Internet at
* http://www.illumos.org/license/CDDL.
*/
/*
* Copyright 2021 OmniOS Community Edition (OmniOSce) Association.
*/
/*
* Two privilege sets are maintained. One which is the minimal privileges
* necessary to run bhyve - 'bhyve_priv_min' - and one which is the maximum
* privileges required - 'bhyve_priv_max'. This second set starts off identical
* to the first, and is added to by modules during initialisation depending on
* their requirements and their configuration.
* Once all modules are initialised, and before the VM is set running, the
* privileges are locked by setting the 'Permitted' privilege set from the
* contents of the maximum set, which is now the upper bound, and dropping back
* to the minimum set.
*
* Privileges are process wide, and this framework does not support threaded
* access. The ID of the thread that first initialises privileges is recorded,
* and all subsequent privilege operations must be done by the same thread.
*/
#include <err.h>
#include <pthread.h>
#include <priv.h>
#include <stdlib.h>
#include <string.h>
#include <upanic.h>
#include <sys/debug.h>
#include "config.h"
#include "debug.h"
#include "privileges.h"
static pthread_t priv_thread;
static priv_set_t *bhyve_priv_init;
static priv_set_t *bhyve_priv_min;
static priv_set_t *bhyve_priv_max;
static bool priv_debug = false;
#define DPRINTF(params) \
if (priv_debug) do { PRINTLN params; fflush(stdout); } while (0)
static void
illumos_priv_printset(const char *tag, priv_set_t *set)
{
char *s;
s = priv_set_to_str(set, ',', PRIV_STR_LIT);
if (s == NULL) {
warn("priv_set_to_str(%s) failed", tag);
return;
}
DPRINTF((" + %s: %s", tag, s));
free(s);
}
void
illumos_priv_reduce(void)
{
VERIFY3S(pthread_equal(pthread_self(), priv_thread), !=, 0);
DPRINTF((" + Reducing privileges to minimum"));
if (setppriv(PRIV_SET, PRIV_EFFECTIVE, bhyve_priv_min) != 0)
err(4, "failed to reduce privileges");
}
static void
illumos_priv_add_set(priv_set_t *set, const char *priv, const char *src)
{
VERIFY3S(pthread_equal(pthread_self(), priv_thread), !=, 0);
DPRINTF((" + Adding privilege %s (%s)", priv, src));
if (!priv_ismember(bhyve_priv_init, priv))
errx(4, "Privilege %s (for %s) not in initial set", priv, src);
if (priv_addset(set, priv) != 0)
err(4, "Failed to add %s privilege for %s", priv, src);
}
void
illumos_priv_add(const char *priv, const char *src)
{
illumos_priv_add_set(bhyve_priv_max, priv, src);
}
void
illumos_priv_add_min(const char *priv, const char *src)
{
illumos_priv_add_set(bhyve_priv_min, priv, src);
illumos_priv_add_set(bhyve_priv_max, priv, src);
}
void
illumos_priv_init(void)
{
priv_debug = get_config_bool_default("privileges.debug", false);
DPRINTF((" + Initialising privileges."));
if (priv_debug)
(void) setpflags(PRIV_DEBUG, 1);
priv_thread = pthread_self();
if ((bhyve_priv_init = priv_allocset()) == NULL)
err(4, "failed to allocate memory for initial priv set");
if ((bhyve_priv_min = priv_allocset()) == NULL)
err(4, "failed to allocate memory for minimum priv set");
if ((bhyve_priv_max = priv_allocset()) == NULL)
err(4, "failed to allocate memory for maximum priv set");
if (getppriv(PRIV_EFFECTIVE, bhyve_priv_init) != 0)
err(4, "failed to fetch current privileges");
if (priv_debug)
illumos_priv_printset("initial", bhyve_priv_init);
/*
* file_read is left in the minimum set to allow for lazy library
* loading.
*/
priv_basicset(bhyve_priv_min);
VERIFY0(priv_delset(bhyve_priv_min, PRIV_FILE_LINK_ANY));
VERIFY0(priv_delset(bhyve_priv_min, PRIV_FILE_WRITE));
VERIFY0(priv_delset(bhyve_priv_min, PRIV_NET_ACCESS));
VERIFY0(priv_delset(bhyve_priv_min, PRIV_PROC_EXEC));
VERIFY0(priv_delset(bhyve_priv_min, PRIV_PROC_FORK));
VERIFY0(priv_delset(bhyve_priv_min, PRIV_PROC_INFO));
VERIFY0(priv_delset(bhyve_priv_min, PRIV_PROC_SECFLAGS));
VERIFY0(priv_delset(bhyve_priv_min, PRIV_PROC_SESSION));
priv_intersect(bhyve_priv_init, bhyve_priv_min);
priv_copyset(bhyve_priv_min, bhyve_priv_max);
/*
* These are privileges that we know will always be needed.
* Other privileges may be added by modules as necessary during
* initialisation.
*/
illumos_priv_add(PRIV_FILE_WRITE, "init");
/*
* bhyve can work without proc_clock_highres so don't enforce that
* it is present.
*/
if (priv_ismember(bhyve_priv_init, PRIV_PROC_CLOCK_HIGHRES))
illumos_priv_add_min(PRIV_PROC_CLOCK_HIGHRES, "init");
else
warnx("The 'proc_clock_highres' privilege is not available");
}
void
illumos_priv_lock(void)
{
VERIFY3S(pthread_equal(pthread_self(), priv_thread), !=, 0);
if (bhyve_priv_init == NULL) {
const char *msg = "attempted to re-lock privileges";
upanic(msg, strlen(msg));
}
priv_intersect(bhyve_priv_init, bhyve_priv_max);
if (priv_debug) {
DPRINTF((" + Locking privileges"));
illumos_priv_printset("min", bhyve_priv_min);
illumos_priv_printset("max", bhyve_priv_max);
}
if (setppriv(PRIV_SET, PRIV_PERMITTED, bhyve_priv_max) != 0) {
const char *fail = "failed to reduce permitted privileges";
upanic(fail, strlen(fail));
}
if (setppriv(PRIV_SET, PRIV_LIMIT, bhyve_priv_max) != 0) {
const char *fail = "failed to reduce limit privileges";
upanic(fail, strlen(fail));
}
illumos_priv_reduce();
priv_freeset(bhyve_priv_init);
bhyve_priv_init = NULL;
}
|
