summaryrefslogtreecommitdiff
path: root/src/core/condition.c
blob: 16cae6d23b6555a734e903b81fac9091ef251822 (plain)
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
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  This file is part of systemd.

  Copyright 2010 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/capability.h>
#include <sys/statvfs.h>
#include <fnmatch.h>

#ifdef HAVE_SELINUX
#include <selinux/selinux.h>
#endif

#include <systemd/sd-id128.h>
#include "util.h"
#include "condition.h"
#include "virt.h"
#include "path-util.h"
#include "fileio.h"

Condition* condition_new(ConditionType type, const char *parameter, bool trigger, bool negate) {
        Condition *c;

        assert(type < _CONDITION_TYPE_MAX);

        c = new0(Condition, 1);
        if (!c)
                return NULL;

        c->type = type;
        c->trigger = trigger;
        c->negate = negate;

        if (parameter) {
                c->parameter = strdup(parameter);
                if (!c->parameter) {
                        free(c);
                        return NULL;
                }
        }

        return c;
}

void condition_free(Condition *c) {
        assert(c);

        free(c->parameter);
        free(c);
}

void condition_free_list(Condition *first) {
        Condition *c, *n;

        LIST_FOREACH_SAFE(conditions, c, n, first)
                condition_free(c);
}

static bool test_kernel_command_line(const char *parameter) {
        char *line, *w, *state, *word = NULL;
        bool equal;
        int r;
        size_t l, pl;
        bool found = false;

        assert(parameter);

        if (detect_container(NULL) > 0)
                return false;

        r = read_one_line_file("/proc/cmdline", &line);
        if (r < 0) {
                log_warning("Failed to read /proc/cmdline, ignoring: %s", strerror(-r));
                return false;
        }

        equal = !!strchr(parameter, '=');
        pl = strlen(parameter);

        FOREACH_WORD_QUOTED(w, l, line, state) {

                free(word);
                word = strndup(w, l);
                if (!word)
                        break;

                if (equal) {
                        if (streq(word, parameter)) {
                                found = true;
                                break;
                        }
                } else {
                        if (startswith(word, parameter) && (word[pl] == '=' || word[pl] == 0)) {
                                found = true;
                                break;
                        }
                }

        }

        free(word);
        free(line);

        return found;
}

static bool test_virtualization(const char *parameter) {
        int b;
        Virtualization v;
        const char *id;

        assert(parameter);

        v = detect_virtualization(&id);
        if (v < 0) {
                log_warning("Failed to detect virtualization, ignoring: %s", strerror(-v));
                return false;
        }

        /* First, compare with yes/no */
        b = parse_boolean(parameter);

        if (v > 0 && b > 0)
                return true;

        if (v == 0 && b == 0)
                return true;

        /* Then, compare categorization */
        if (v == VIRTUALIZATION_VM && streq(parameter, "vm"))
                return true;

        if (v == VIRTUALIZATION_CONTAINER && streq(parameter, "container"))
                return true;

        /* Finally compare id */
        return v > 0 && streq(parameter, id);
}

static bool test_security(const char *parameter) {
#ifdef HAVE_SELINUX
        if (streq(parameter, "selinux"))
                return is_selinux_enabled() > 0;
#endif
	if (streq(parameter, "apparmor"))
		return access("/sys/kernel/security/apparmor/", F_OK) == 0;
	if (streq(parameter, "smack"))
		return access("/sys/fs/smackfs", F_OK) == 0;
        return false;
}

static bool test_capability(const char *parameter) {
        cap_value_t value;
        FILE *f;
        char line[LINE_MAX];
        unsigned long long capabilities = (unsigned long long) -1;

        /* If it's an invalid capability, we don't have it */

        if (cap_from_name(parameter, &value) < 0)
                return false;

        /* If it's a valid capability we default to assume
         * that we have it */

        f = fopen("/proc/self/status", "re");
        if (!f)
                return true;

        while (fgets(line, sizeof(line), f)) {
                truncate_nl(line);

                if (startswith(line, "CapBnd:")) {
                        (void) sscanf(line+7, "%llx", &capabilities);
                        break;
                }
        }

        fclose(f);

        return !!(capabilities & (1ULL << value));
}

static bool test_host(const char *parameter) {
        sd_id128_t x, y;
        char *h;
        int r;
        bool b;

        if (sd_id128_from_string(parameter, &x) >= 0) {

                r = sd_id128_get_machine(&y);
                if (r < 0)
                        return false;

                return sd_id128_equal(x, y);
        }

        h = gethostname_malloc();
        if (!h)
                return false;

        b = fnmatch(parameter, h, FNM_CASEFOLD) == 0;
        free(h);

        return b;
}

static bool test_ac_power(const char *parameter) {
        int r;

        r = parse_boolean(parameter);
        if (r < 0)
                return true;

        return (on_ac_power() != 0) == !!r;
}

bool condition_test(Condition *c) {
        assert(c);

        switch(c->type) {

        case CONDITION_PATH_EXISTS:
                return (access(c->parameter, F_OK) >= 0) == !c->negate;

        case CONDITION_PATH_EXISTS_GLOB:
                return (glob_exists(c->parameter) > 0) == !c->negate;

        case CONDITION_PATH_IS_DIRECTORY: {
                struct stat st;

                if (stat(c->parameter, &st) < 0)
                        return c->negate;
                return S_ISDIR(st.st_mode) == !c->negate;
        }

        case CONDITION_PATH_IS_SYMBOLIC_LINK: {
                struct stat st;

                if (lstat(c->parameter, &st) < 0)
                        return c->negate;
                return S_ISLNK(st.st_mode) == !c->negate;
        }

        case CONDITION_PATH_IS_MOUNT_POINT:
                return (path_is_mount_point(c->parameter, true) > 0) == !c->negate;

        case CONDITION_PATH_IS_READ_WRITE:
                return (path_is_read_only_fs(c->parameter) > 0) == c->negate;

        case CONDITION_DIRECTORY_NOT_EMPTY: {
                int k;

                k = dir_is_empty(c->parameter);
                return !(k == -ENOENT || k > 0) == !c->negate;
        }

        case CONDITION_FILE_NOT_EMPTY: {
                struct stat st;

                if (stat(c->parameter, &st) < 0)
                        return c->negate;

                return (S_ISREG(st.st_mode) && st.st_size > 0) == !c->negate;
        }

        case CONDITION_FILE_IS_EXECUTABLE: {
                struct stat st;

                if (stat(c->parameter, &st) < 0)
                        return c->negate;

                return (S_ISREG(st.st_mode) && (st.st_mode & 0111)) == !c->negate;
        }

        case CONDITION_KERNEL_COMMAND_LINE:
                return test_kernel_command_line(c->parameter) == !c->negate;

        case CONDITION_VIRTUALIZATION:
                return test_virtualization(c->parameter) == !c->negate;

        case CONDITION_SECURITY:
                return test_security(c->parameter) == !c->negate;

        case CONDITION_CAPABILITY:
                return test_capability(c->parameter) == !c->negate;

        case CONDITION_HOST:
                return test_host(c->parameter) == !c->negate;

        case CONDITION_AC_POWER:
                return test_ac_power(c->parameter) == !c->negate;

        case CONDITION_NULL:
                return !c->negate;

        default:
                assert_not_reached("Invalid condition type.");
        }
}

bool condition_test_list(Condition *first) {
        Condition *c;
        int triggered = -1;

        /* If the condition list is empty, then it is true */
        if (!first)
                return true;

        /* Otherwise, if all of the non-trigger conditions apply and
         * if any of the trigger conditions apply (unless there are
         * none) we return true */
        LIST_FOREACH(conditions, c, first) {
                bool b;

                b = condition_test(c);

                if (!c->trigger && !b)
                        return false;

                if (c->trigger && triggered <= 0)
                        triggered = b;
        }

        return triggered != 0;
}

void condition_dump(Condition *c, FILE *f, const char *prefix) {
        assert(c);
        assert(f);

        if (!prefix)
                prefix = "";

        fprintf(f,
                "%s\t%s: %s%s%s\n",
                prefix,
                condition_type_to_string(c->type),
                c->trigger ? "|" : "",
                c->negate ? "!" : "",
                c->parameter);
}

void condition_dump_list(Condition *first, FILE *f, const char *prefix) {
        Condition *c;

        LIST_FOREACH(conditions, c, first)
                condition_dump(c, f, prefix);
}

static const char* const condition_type_table[_CONDITION_TYPE_MAX] = {
        [CONDITION_PATH_EXISTS] = "ConditionPathExists",
        [CONDITION_PATH_EXISTS_GLOB] = "ConditionPathExistsGlob",
        [CONDITION_PATH_IS_DIRECTORY] = "ConditionPathIsDirectory",
        [CONDITION_PATH_IS_SYMBOLIC_LINK] = "ConditionPathIsSymbolicLink",
        [CONDITION_PATH_IS_MOUNT_POINT] = "ConditionPathIsMountPoint",
        [CONDITION_PATH_IS_READ_WRITE] = "ConditionPathIsReadWrite",
        [CONDITION_DIRECTORY_NOT_EMPTY] = "ConditionDirectoryNotEmpty",
        [CONDITION_FILE_NOT_EMPTY] = "ConditionFileNotEmpty",
        [CONDITION_KERNEL_COMMAND_LINE] = "ConditionKernelCommandLine",
        [CONDITION_VIRTUALIZATION] = "ConditionVirtualization",
        [CONDITION_SECURITY] = "ConditionSecurity",
        [CONDITION_HOST] = "ConditionHost",
        [CONDITION_AC_POWER] = "ConditionACPower",
        [CONDITION_NULL] = "ConditionNull"
};

DEFINE_STRING_TABLE_LOOKUP(condition_type, ConditionType);