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
|
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include "chase.h"
#include "fd-util.h"
#include "fileio.h"
#include "missing_threads.h"
#include "string-util.h"
#include "uid-classification.h"
#include "user-util.h"
static const UGIDAllocationRange default_ugid_allocation_range = {
.system_alloc_uid_min = SYSTEM_ALLOC_UID_MIN,
.system_uid_max = SYSTEM_UID_MAX,
.system_alloc_gid_min = SYSTEM_ALLOC_GID_MIN,
.system_gid_max = SYSTEM_GID_MAX,
};
#if ENABLE_COMPAT_MUTABLE_UID_BOUNDARIES
static int parse_alloc_uid(const char *path, const char *name, const char *t, uid_t *ret_uid) {
uid_t uid;
int r;
r = parse_uid(t, &uid);
if (r < 0)
return log_debug_errno(r, "%s: failed to parse %s %s, ignoring: %m", path, name, t);
if (uid == 0)
uid = 1;
*ret_uid = uid;
return 0;
}
#endif
int read_login_defs(UGIDAllocationRange *ret_defs, const char *path, const char *root) {
#if ENABLE_COMPAT_MUTABLE_UID_BOUNDARIES
_cleanup_fclose_ FILE *f = NULL;
UGIDAllocationRange defs;
int r;
if (!path)
path = "/etc/login.defs";
r = chase_and_fopen_unlocked(path, root, CHASE_PREFIX_ROOT, "re", NULL, &f);
if (r == -ENOENT)
goto defaults;
if (r < 0)
return log_debug_errno(r, "Failed to open %s: %m", path);
defs = default_ugid_allocation_range;
for (;;) {
_cleanup_free_ char *line = NULL;
char *t;
r = read_line(f, LINE_MAX, &line);
if (r < 0)
return log_debug_errno(r, "Failed to read %s: %m", path);
if (r == 0)
break;
if ((t = first_word(line, "SYS_UID_MIN")))
(void) parse_alloc_uid(path, "SYS_UID_MIN", t, &defs.system_alloc_uid_min);
else if ((t = first_word(line, "SYS_UID_MAX")))
(void) parse_alloc_uid(path, "SYS_UID_MAX", t, &defs.system_uid_max);
else if ((t = first_word(line, "SYS_GID_MIN")))
(void) parse_alloc_uid(path, "SYS_GID_MIN", t, &defs.system_alloc_gid_min);
else if ((t = first_word(line, "SYS_GID_MAX")))
(void) parse_alloc_uid(path, "SYS_GID_MAX", t, &defs.system_gid_max);
}
if (defs.system_alloc_uid_min > defs.system_uid_max) {
log_debug("%s: SYS_UID_MIN > SYS_UID_MAX, resetting.", path);
defs.system_alloc_uid_min = MIN(defs.system_uid_max - 1, (uid_t) SYSTEM_ALLOC_UID_MIN);
/* Look at sys_uid_max to make sure sys_uid_min..sys_uid_max remains a valid range. */
}
if (defs.system_alloc_gid_min > defs.system_gid_max) {
log_debug("%s: SYS_GID_MIN > SYS_GID_MAX, resetting.", path);
defs.system_alloc_gid_min = MIN(defs.system_gid_max - 1, (gid_t) SYSTEM_ALLOC_GID_MIN);
/* Look at sys_gid_max to make sure sys_gid_min..sys_gid_max remains a valid range. */
}
*ret_defs = defs;
return 1;
defaults:
#endif
*ret_defs = default_ugid_allocation_range;
return 0;
}
const UGIDAllocationRange *acquire_ugid_allocation_range(void) {
#if ENABLE_COMPAT_MUTABLE_UID_BOUNDARIES
static thread_local UGIDAllocationRange defs;
static thread_local int initialized = 0; /* == 0 → not initialized yet
* < 0 → failure
* > 0 → success */
/* This function will ignore failure to read the file, so it should only be called from places where
* we don't crucially depend on the answer. In other words, it's appropriate for journald, but
* probably not for sysusers. */
if (initialized == 0)
initialized = read_login_defs(&defs, NULL, NULL) < 0 ? -1 : 1;
if (initialized < 0)
return &default_ugid_allocation_range;
return &defs;
#endif
return &default_ugid_allocation_range;
}
bool uid_is_system(uid_t uid) {
const UGIDAllocationRange *defs;
assert_se(defs = acquire_ugid_allocation_range());
return uid <= defs->system_uid_max;
}
bool gid_is_system(gid_t gid) {
const UGIDAllocationRange *defs;
assert_se(defs = acquire_ugid_allocation_range());
return gid <= defs->system_gid_max;
}
bool uid_for_system_journal(uid_t uid) {
/* Returns true if the specified UID shall get its data stored in the system journal. */
return uid_is_system(uid) || uid_is_dynamic(uid) || uid == UID_NOBODY || uid_is_container(uid);
}
|
