src/shared/condition.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <errno.h>
  23 #include <fnmatch.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <unistd.h>
  27
  28 #include "sd-id128.h"
  29
  30 #include "apparmor-util.h"
  31 #include "architecture.h"
  32 #include "audit.h"
  33 #include "cap-list.h"
  34 #include "extract-word.h"
  35 #include "hostname-util.h"
  36 #include "ima-util.h"
  37 #include "path-util.h"
  38 #include "selinux-util.h"
  39 #include "smack-util.h"
  40 #include "string-util.h"
  41 #include "util.h"
  42 #include "virt.h"
  43 #include "condition.h"
  44
  45 Condition* condition_new(ConditionType type, const char *parameter, bool trigger, bool negate) {
  46         Condition *c;
  47         int r;
  48
  49         assert(type >= 0);
  50         assert(type < _CONDITION_TYPE_MAX);
  51         assert((!parameter) == (type == CONDITION_NULL));
  52
  53         c = new0(Condition, 1);
  54         if (!c)
  55                 return NULL;
  56
  57         c->type = type;
  58         c->trigger = trigger;
  59         c->negate = negate;
  60
  61         r = free_and_strdup(&c->parameter, parameter);
  62         if (r < 0) {
  63                 free(c);
  64                 return NULL;
  65         }
  66
  67         return c;
  68 }
  69
  70 void condition_free(Condition *c) {
  71         assert(c);
  72
  73         free(c->parameter);
  74         free(c);
  75 }
  76
  77 Condition* condition_free_list(Condition *first) {
  78         Condition *c, *n;
  79
  80         LIST_FOREACH_SAFE(conditions, c, n, first)
  81                 condition_free(c);
  82
  83         return NULL;
  84 }
  85
  86 static int condition_test_kernel_command_line(Condition *c) {
  87         _cleanup_free_ char *line = NULL;
  88         const char *p;
  89         bool equal;
  90         int r;
  91
  92         assert(c);
  93         assert(c->parameter);
  94         assert(c->type == CONDITION_KERNEL_COMMAND_LINE);
  95
  96         r = proc_cmdline(&line);
  97         if (r < 0)
  98                 return r;
  99
 100         equal = !!strchr(c->parameter, '=');
 101         p = line;
 102
 103         for (;;) {
 104                 _cleanup_free_ char *word = NULL;
 105                 bool found;
 106
 107                 r = extract_first_word(&p, &word, NULL, EXTRACT_QUOTES|EXTRACT_RELAX);
 108                 if (r < 0)
 109                         return r;
 110                 if (r == 0)
 111                         break;
 112
 113                 if (equal)
 114                         found = streq(word, c->parameter);
 115                 else {
 116                         const char *f;
 117
 118                         f = startswith(word, c->parameter);
 119                         found = f && (*f == '=' || *f == 0);
 120                 }
 121
 122                 if (found)
 123                         return true;
 124         }
 125
 126         return false;
 127 }
 128
 129 static int condition_test_virtualization(Condition *c) {
 130         int b, v;
 131
 132         assert(c);
 133         assert(c->parameter);
 134         assert(c->type == CONDITION_VIRTUALIZATION);
 135
 136         v = detect_virtualization();
 137         if (v < 0)
 138                 return v;
 139
 140         /* First, compare with yes/no */
 141         b = parse_boolean(c->parameter);
 142
 143         if (v > 0 && b > 0)
 144                 return true;
 145
 146         if (v == 0 && b == 0)
 147                 return true;
 148
 149         /* Then, compare categorization */
 150         if (VIRTUALIZATION_IS_VM(v) && streq(c->parameter, "vm"))
 151                 return true;
 152
 153         if (VIRTUALIZATION_IS_CONTAINER(v) && streq(c->parameter, "container"))
 154                 return true;
 155
 156         /* Finally compare id */
 157         return v != VIRTUALIZATION_NONE && streq(c->parameter, virtualization_to_string(v));
 158 }
 159
 160 static int condition_test_architecture(Condition *c) {
 161         int a, b;
 162
 163         assert(c);
 164         assert(c->parameter);
 165         assert(c->type == CONDITION_ARCHITECTURE);
 166
 167         a = uname_architecture();
 168         if (a < 0)
 169                 return a;
 170
 171         if (streq(c->parameter, "native"))
 172                 b = native_architecture();
 173         else
 174                 b = architecture_from_string(c->parameter);
 175         if (b < 0)
 176                 return b;
 177
 178         return a == b;
 179 }
 180
 181 static int condition_test_host(Condition *c) {
 182         _cleanup_free_ char *h = NULL;
 183         sd_id128_t x, y;
 184         int r;
 185
 186         assert(c);
 187         assert(c->parameter);
 188         assert(c->type == CONDITION_HOST);
 189
 190         if (sd_id128_from_string(c->parameter, &x) >= 0) {
 191
 192                 r = sd_id128_get_machine(&y);
 193                 if (r < 0)
 194                         return r;
 195
 196                 return sd_id128_equal(x, y);
 197         }
 198
 199         h = gethostname_malloc();
 200         if (!h)
 201                 return -ENOMEM;
 202
 203         return fnmatch(c->parameter, h, FNM_CASEFOLD) == 0;
 204 }
 205
 206 static int condition_test_ac_power(Condition *c) {
 207         int r;
 208
 209         assert(c);
 210         assert(c->parameter);
 211         assert(c->type == CONDITION_AC_POWER);
 212
 213         r = parse_boolean(c->parameter);
 214         if (r < 0)
 215                 return r;
 216
 217         return (on_ac_power() != 0) == !!r;
 218 }
 219
 220 static int condition_test_security(Condition *c) {
 221         assert(c);
 222         assert(c->parameter);
 223         assert(c->type == CONDITION_SECURITY);
 224
 225         if (streq(c->parameter, "selinux"))
 226                 return mac_selinux_use();
 227         if (streq(c->parameter, "smack"))
 228                 return mac_smack_use();
 229         if (streq(c->parameter, "apparmor"))
 230                 return mac_apparmor_use();
 231         if (streq(c->parameter, "audit"))
 232                 return use_audit();
 233         if (streq(c->parameter, "ima"))
 234                 return use_ima();
 235
 236         return false;
 237 }
 238
 239 static int condition_test_capability(Condition *c) {
 240         _cleanup_fclose_ FILE *f = NULL;
 241         int value;
 242         char line[LINE_MAX];
 243         unsigned long long capabilities = -1;
 244
 245         assert(c);
 246         assert(c->parameter);
 247         assert(c->type == CONDITION_CAPABILITY);
 248
 249         /* If it's an invalid capability, we don't have it */
 250         value = capability_from_name(c->parameter);
 251         if (value < 0)
 252                 return -EINVAL;
 253
 254         /* If it's a valid capability we default to assume
 255          * that we have it */
 256
 257         f = fopen("/proc/self/status", "re");
 258         if (!f)
 259                 return -errno;
 260
 261         while (fgets(line, sizeof(line), f)) {
 262                 truncate_nl(line);
 263
 264                 if (startswith(line, "CapBnd:")) {
 265                         (void) sscanf(line+7, "%llx", &capabilities);
 266                         break;
 267                 }
 268         }
 269
 270         return !!(capabilities & (1ULL << value));
 271 }
 272
 273 static int condition_test_needs_update(Condition *c) {
 274         const char *p;
 275         struct stat usr, other;
 276
 277         assert(c);
 278         assert(c->parameter);
 279         assert(c->type == CONDITION_NEEDS_UPDATE);
 280
 281         /* If the file system is read-only we shouldn't suggest an update */
 282         if (path_is_read_only_fs(c->parameter) > 0)
 283                 return false;
 284
 285         /* Any other failure means we should allow the condition to be true,
 286          * so that we rather invoke too many update tools then too
 287          * few. */
 288
 289         if (!path_is_absolute(c->parameter))
 290                 return true;
 291
 292         p = strjoina(c->parameter, "/.updated");
 293         if (lstat(p, &other) < 0)
 294                 return true;
 295
 296         if (lstat("/usr/", &usr) < 0)
 297                 return true;
 298
 299         return usr.st_mtim.tv_sec > other.st_mtim.tv_sec ||
 300                 (usr.st_mtim.tv_sec == other.st_mtim.tv_sec && usr.st_mtim.tv_nsec > other.st_mtim.tv_nsec);
 301 }
 302
 303 static int condition_test_first_boot(Condition *c) {
 304         int r;
 305
 306         assert(c);
 307         assert(c->parameter);
 308         assert(c->type == CONDITION_FIRST_BOOT);
 309
 310         r = parse_boolean(c->parameter);
 311         if (r < 0)
 312                 return r;
 313
 314         return (access("/run/systemd/first-boot", F_OK) >= 0) == !!r;
 315 }
 316
 317 static int condition_test_path_exists(Condition *c) {
 318         assert(c);
 319         assert(c->parameter);
 320         assert(c->type == CONDITION_PATH_EXISTS);
 321
 322         return access(c->parameter, F_OK) >= 0;
 323 }
 324
 325 static int condition_test_path_exists_glob(Condition *c) {
 326         assert(c);
 327         assert(c->parameter);
 328         assert(c->type == CONDITION_PATH_EXISTS_GLOB);
 329
 330         return glob_exists(c->parameter) > 0;
 331 }
 332
 333 static int condition_test_path_is_directory(Condition *c) {
 334         assert(c);
 335         assert(c->parameter);
 336         assert(c->type == CONDITION_PATH_IS_DIRECTORY);
 337
 338         return is_dir(c->parameter, true) > 0;
 339 }
 340
 341 static int condition_test_path_is_symbolic_link(Condition *c) {
 342         assert(c);
 343         assert(c->parameter);
 344         assert(c->type == CONDITION_PATH_IS_SYMBOLIC_LINK);
 345
 346         return is_symlink(c->parameter) > 0;
 347 }
 348
 349 static int condition_test_path_is_mount_point(Condition *c) {
 350         assert(c);
 351         assert(c->parameter);
 352         assert(c->type == CONDITION_PATH_IS_MOUNT_POINT);
 353
 354         return path_is_mount_point(c->parameter, AT_SYMLINK_FOLLOW) > 0;
 355 }
 356
 357 static int condition_test_path_is_read_write(Condition *c) {
 358         assert(c);
 359         assert(c->parameter);
 360         assert(c->type == CONDITION_PATH_IS_READ_WRITE);
 361
 362         return path_is_read_only_fs(c->parameter) <= 0;
 363 }
 364
 365 static int condition_test_directory_not_empty(Condition *c) {
 366         int r;
 367
 368         assert(c);
 369         assert(c->parameter);
 370         assert(c->type == CONDITION_DIRECTORY_NOT_EMPTY);
 371
 372         r = dir_is_empty(c->parameter);
 373         return r <= 0 && r != -ENOENT;
 374 }
 375
 376 static int condition_test_file_not_empty(Condition *c) {
 377         struct stat st;
 378
 379         assert(c);
 380         assert(c->parameter);
 381         assert(c->type == CONDITION_FILE_NOT_EMPTY);
 382
 383         return (stat(c->parameter, &st) >= 0 &&
 384                 S_ISREG(st.st_mode) &&
 385                 st.st_size > 0);
 386 }
 387
 388 static int condition_test_file_is_executable(Condition *c) {
 389         struct stat st;
 390
 391         assert(c);
 392         assert(c->parameter);
 393         assert(c->type == CONDITION_FILE_IS_EXECUTABLE);
 394
 395         return (stat(c->parameter, &st) >= 0 &&
 396                 S_ISREG(st.st_mode) &&
 397                 (st.st_mode & 0111));
 398 }
 399
 400 static int condition_test_null(Condition *c) {
 401         assert(c);
 402         assert(c->type == CONDITION_NULL);
 403
 404         /* Note that during parsing we already evaluate the string and
 405          * store it in c->negate */
 406         return true;
 407 }
 408
 409 int condition_test(Condition *c) {
 410
 411         static int (*const condition_tests[_CONDITION_TYPE_MAX])(Condition *c) = {
 412                 [CONDITION_PATH_EXISTS] = condition_test_path_exists,
 413                 [CONDITION_PATH_EXISTS_GLOB] = condition_test_path_exists_glob,
 414                 [CONDITION_PATH_IS_DIRECTORY] = condition_test_path_is_directory,
 415                 [CONDITION_PATH_IS_SYMBOLIC_LINK] = condition_test_path_is_symbolic_link,
 416                 [CONDITION_PATH_IS_MOUNT_POINT] = condition_test_path_is_mount_point,
 417                 [CONDITION_PATH_IS_READ_WRITE] = condition_test_path_is_read_write,
 418                 [CONDITION_DIRECTORY_NOT_EMPTY] = condition_test_directory_not_empty,
 419                 [CONDITION_FILE_NOT_EMPTY] = condition_test_file_not_empty,
 420                 [CONDITION_FILE_IS_EXECUTABLE] = condition_test_file_is_executable,
 421                 [CONDITION_KERNEL_COMMAND_LINE] = condition_test_kernel_command_line,
 422                 [CONDITION_VIRTUALIZATION] = condition_test_virtualization,
 423                 [CONDITION_SECURITY] = condition_test_security,
 424                 [CONDITION_CAPABILITY] = condition_test_capability,
 425                 [CONDITION_HOST] = condition_test_host,
 426                 [CONDITION_AC_POWER] = condition_test_ac_power,
 427                 [CONDITION_ARCHITECTURE] = condition_test_architecture,
 428                 [CONDITION_NEEDS_UPDATE] = condition_test_needs_update,
 429                 [CONDITION_FIRST_BOOT] = condition_test_first_boot,
 430                 [CONDITION_NULL] = condition_test_null,
 431         };
 432
 433         int r, b;
 434
 435         assert(c);
 436         assert(c->type >= 0);
 437         assert(c->type < _CONDITION_TYPE_MAX);
 438
 439         r = condition_tests[c->type](c);
 440         if (r < 0) {
 441                 c->result = CONDITION_ERROR;
 442                 return r;
 443         }
 444
 445         b = (r > 0) == !c->negate;
 446         c->result = b ? CONDITION_SUCCEEDED : CONDITION_FAILED;
 447         return b;
 448 }
 449
 450 void condition_dump(Condition *c, FILE *f, const char *prefix, const char *(*to_string)(ConditionType t)) {
 451         assert(c);
 452         assert(f);
 453
 454         if (!prefix)
 455                 prefix = "";
 456
 457         fprintf(f,
 458                 "%s\t%s: %s%s%s %s\n",
 459                 prefix,
 460                 to_string(c->type),
 461                 c->trigger ? "|" : "",
 462                 c->negate ? "!" : "",
 463                 c->parameter,
 464                 condition_result_to_string(c->result));
 465 }
 466
 467 void condition_dump_list(Condition *first, FILE *f, const char *prefix, const char *(*to_string)(ConditionType t)) {
 468         Condition *c;
 469
 470         LIST_FOREACH(conditions, c, first)
 471                 condition_dump(c, f, prefix, to_string);
 472 }
 473
 474 static const char* const condition_type_table[_CONDITION_TYPE_MAX] = {
 475         [CONDITION_ARCHITECTURE] = "ConditionArchitecture",
 476         [CONDITION_VIRTUALIZATION] = "ConditionVirtualization",
 477         [CONDITION_HOST] = "ConditionHost",
 478         [CONDITION_KERNEL_COMMAND_LINE] = "ConditionKernelCommandLine",
 479         [CONDITION_SECURITY] = "ConditionSecurity",
 480         [CONDITION_CAPABILITY] = "ConditionCapability",
 481         [CONDITION_AC_POWER] = "ConditionACPower",
 482         [CONDITION_NEEDS_UPDATE] = "ConditionNeedsUpdate",
 483         [CONDITION_FIRST_BOOT] = "ConditionFirstBoot",
 484         [CONDITION_PATH_EXISTS] = "ConditionPathExists",
 485         [CONDITION_PATH_EXISTS_GLOB] = "ConditionPathExistsGlob",
 486         [CONDITION_PATH_IS_DIRECTORY] = "ConditionPathIsDirectory",
 487         [CONDITION_PATH_IS_SYMBOLIC_LINK] = "ConditionPathIsSymbolicLink",
 488         [CONDITION_PATH_IS_MOUNT_POINT] = "ConditionPathIsMountPoint",
 489         [CONDITION_PATH_IS_READ_WRITE] = "ConditionPathIsReadWrite",
 490         [CONDITION_DIRECTORY_NOT_EMPTY] = "ConditionDirectoryNotEmpty",
 491         [CONDITION_FILE_NOT_EMPTY] = "ConditionFileNotEmpty",
 492         [CONDITION_FILE_IS_EXECUTABLE] = "ConditionFileIsExecutable",
 493         [CONDITION_NULL] = "ConditionNull"
 494 };
 495
 496 DEFINE_STRING_TABLE_LOOKUP(condition_type, ConditionType);
 497
 498 static const char* const assert_type_table[_CONDITION_TYPE_MAX] = {
 499         [CONDITION_ARCHITECTURE] = "AssertArchitecture",
 500         [CONDITION_VIRTUALIZATION] = "AssertVirtualization",
 501         [CONDITION_HOST] = "AssertHost",
 502         [CONDITION_KERNEL_COMMAND_LINE] = "AssertKernelCommandLine",
 503         [CONDITION_SECURITY] = "AssertSecurity",
 504         [CONDITION_CAPABILITY] = "AssertCapability",
 505         [CONDITION_AC_POWER] = "AssertACPower",
 506         [CONDITION_NEEDS_UPDATE] = "AssertNeedsUpdate",
 507         [CONDITION_FIRST_BOOT] = "AssertFirstBoot",
 508         [CONDITION_PATH_EXISTS] = "AssertPathExists",
 509         [CONDITION_PATH_EXISTS_GLOB] = "AssertPathExistsGlob",
 510         [CONDITION_PATH_IS_DIRECTORY] = "AssertPathIsDirectory",
 511         [CONDITION_PATH_IS_SYMBOLIC_LINK] = "AssertPathIsSymbolicLink",
 512         [CONDITION_PATH_IS_MOUNT_POINT] = "AssertPathIsMountPoint",
 513         [CONDITION_PATH_IS_READ_WRITE] = "AssertPathIsReadWrite",
 514         [CONDITION_DIRECTORY_NOT_EMPTY] = "AssertDirectoryNotEmpty",
 515         [CONDITION_FILE_NOT_EMPTY] = "AssertFileNotEmpty",
 516         [CONDITION_FILE_IS_EXECUTABLE] = "AssertFileIsExecutable",
 517         [CONDITION_NULL] = "AssertNull"
 518 };
 519
 520 DEFINE_STRING_TABLE_LOOKUP(assert_type, ConditionType);
 521
 522 static const char* const condition_result_table[_CONDITION_RESULT_MAX] = {
 523         [CONDITION_UNTESTED] = "untested",
 524         [CONDITION_SUCCEEDED] = "succeeded",
 525         [CONDITION_FAILED] = "failed",
 526         [CONDITION_ERROR] = "error",
 527 };
 528
 529 DEFINE_STRING_TABLE_LOOKUP(condition_result, ConditionResult);