src/basic/capability-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <linux/prctl.h>
   4 #include <stdatomic.h>
   5 #include <stdio.h>
   6 #include <sys/prctl.h>
   7 #include <unistd.h>
   8
   9 #include "alloc-util.h"
  10 #include "bitfield.h"
  11 #include "capability-list.h"
  12 #include "capability-util.h"
  13 #include "fd-util.h"
  14 #include "fileio.h"
  15 #include "log.h"
  16 #include "logarithm.h"
  17 #include "parse-util.h"
  18 #include "pidref.h"
  19 #include "process-util.h"
  20 #include "stat-util.h"
  21 #include "user-util.h"
  22
  23 int have_effective_cap(int value) {
  24         _cleanup_cap_free_ cap_t cap = NULL;
  25         cap_flag_value_t fv = CAP_CLEAR; /* To avoid false-positive use-of-uninitialized-value error reported
  26                                           * by fuzzers. */
  27
  28         cap = cap_get_proc();
  29         if (!cap)
  30                 return -errno;
  31
  32         if (cap_get_flag(cap, value, CAP_EFFECTIVE, &fv) < 0)
  33                 return -errno;
  34
  35         return fv == CAP_SET;
  36 }
  37
  38 unsigned cap_last_cap(void) {
  39         static atomic_int saved = INT_MAX;
  40         int r, c;
  41
  42         c = saved;
  43         if (c != INT_MAX)
  44                 return c;
  45
  46         /* Available since linux-3.2 */
  47         _cleanup_free_ char *content = NULL;
  48         r = read_one_line_file("/proc/sys/kernel/cap_last_cap", &content);
  49         if (r < 0)
  50                 log_debug_errno(r, "Failed to read /proc/sys/kernel/cap_last_cap, ignoring: %m");
  51         else {
  52                 r = safe_atoi(content, &c);
  53                 if (r < 0)
  54                         log_debug_errno(r, "Failed to parse /proc/sys/kernel/cap_last_cap, ignoring: %m");
  55                 else {
  56                         if (c > CAP_LIMIT) /* Safety for the future: if one day the kernel learns more than
  57                                             * 64 caps, then we are in trouble (since we, as much userspace
  58                                             * and kernel space store capability masks in uint64_t types). We
  59                                             * also want to use UINT64_MAX as marker for "unset". Hence let's
  60                                             * hence protect ourselves against that and always cap at 62 for
  61                                             * now. */
  62                                 c = CAP_LIMIT;
  63
  64                         saved = c;
  65                         return c;
  66                 }
  67         }
  68
  69         /* Fall back to syscall-probing for pre linux-3.2, or where /proc/ is not mounted */
  70         unsigned long p = (unsigned long) MIN(CAP_LAST_CAP, CAP_LIMIT);
  71
  72         if (prctl(PR_CAPBSET_READ, p) < 0) {
  73
  74                 /* Hmm, look downwards, until we find one that works */
  75                 for (p--; p > 0; p--)
  76                         if (prctl(PR_CAPBSET_READ, p) >= 0)
  77                                 break;
  78
  79         } else {
  80
  81                 /* Hmm, look upwards, until we find one that doesn't work */
  82                 for (; p < CAP_LIMIT; p++)
  83                         if (prctl(PR_CAPBSET_READ, p+1) < 0)
  84                                 break;
  85         }
  86
  87         c = (int) p;
  88         saved = c;
  89         return c;
  90 }
  91
  92 int capability_update_inherited_set(cap_t caps, uint64_t set) {
  93         /* Add capabilities in the set to the inherited caps, drops capabilities not in the set.
  94          * Do not apply them yet. */
  95
  96         for (unsigned i = 0; i <= cap_last_cap(); i++) {
  97                 cap_flag_value_t flag = set & (UINT64_C(1) << i) ? CAP_SET : CAP_CLEAR;
  98                 cap_value_t v;
  99
 100                 v = (cap_value_t) i;
 101
 102                 if (cap_set_flag(caps, CAP_INHERITABLE, 1, &v, flag) < 0)
 103                         return -errno;
 104         }
 105
 106         return 0;
 107 }
 108
 109 int capability_ambient_set_apply(uint64_t set, bool also_inherit) {
 110         _cleanup_cap_free_ cap_t caps = NULL;
 111         int r;
 112
 113         /* Remove capabilities requested in ambient set, but not in the bounding set */
 114         for (unsigned i = 0; i <= cap_last_cap(); i++) {
 115                 if (!BIT_SET(set, i))
 116                         continue;
 117
 118                 if (prctl(PR_CAPBSET_READ, (unsigned long) i) != 1) {
 119                         log_debug("Ambient capability %s requested but missing from bounding set, suppressing automatically.",
 120                                   capability_to_name(i));
 121                         CLEAR_BIT(set, i);
 122                 }
 123         }
 124
 125         /* Add the capabilities to the ambient set (an possibly also the inheritable set) */
 126
 127         if (also_inherit) {
 128                 caps = cap_get_proc();
 129                 if (!caps)
 130                         return -errno;
 131
 132                 r = capability_update_inherited_set(caps, set);
 133                 if (r < 0)
 134                         return -errno;
 135
 136                 if (cap_set_proc(caps) < 0)
 137                         return -errno;
 138         }
 139
 140         for (unsigned i = 0; i <= cap_last_cap(); i++) {
 141                 if (BIT_SET(set, i)) {
 142                         /* Add the capability to the ambient set. */
 143                         if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, i, 0, 0) < 0)
 144                                 return -errno;
 145                 } else {
 146                         /* Drop the capability so we don't inherit capabilities we didn't ask for. */
 147                         r = prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, i, 0, 0);
 148                         if (r < 0)
 149                                 return -errno;
 150                         if (r > 0)
 151                                 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_LOWER, i, 0, 0) < 0)
 152                                         return -errno;
 153                 }
 154         }
 155
 156         return 0;
 157 }
 158
 159 int capability_gain_cap_setpcap(cap_t *ret_before_caps) {
 160         _cleanup_cap_free_ cap_t caps = NULL;
 161         cap_flag_value_t fv;
 162         caps = cap_get_proc();
 163         if (!caps)
 164                 return -errno;
 165
 166         if (cap_get_flag(caps, CAP_SETPCAP, CAP_EFFECTIVE, &fv) < 0)
 167                 return -errno;
 168
 169         if (fv != CAP_SET) {
 170                 _cleanup_cap_free_ cap_t temp_cap = NULL;
 171                 static const cap_value_t v = CAP_SETPCAP;
 172
 173                 temp_cap = cap_dup(caps);
 174                 if (!temp_cap)
 175                         return -errno;
 176
 177                 if (cap_set_flag(temp_cap, CAP_EFFECTIVE, 1, &v, CAP_SET) < 0)
 178                         return -errno;
 179
 180                 if (cap_set_proc(temp_cap) < 0)
 181                         log_debug_errno(errno, "Can't acquire effective CAP_SETPCAP bit, ignoring: %m");
 182
 183                 /* If we didn't manage to acquire the CAP_SETPCAP bit, we continue anyway, after all this just means
 184                  * we'll fail later, when we actually intend to drop some capabilities or try to set securebits. */
 185         }
 186         if (ret_before_caps)
 187                 /* Return the capabilities as they have been before setting CAP_SETPCAP */
 188                 *ret_before_caps = TAKE_PTR(caps);
 189
 190         return 0;
 191 }
 192
 193 int capability_bounding_set_drop(uint64_t keep, bool right_now) {
 194         _cleanup_cap_free_ cap_t before_cap = NULL, after_cap = NULL;
 195         int r;
 196
 197         /* If we are run as PID 1 we will lack CAP_SETPCAP by default
 198          * in the effective set (yes, the kernel drops that when
 199          * executing init!), so get it back temporarily so that we can
 200          * call PR_CAPBSET_DROP. */
 201
 202         r = capability_gain_cap_setpcap(&before_cap);
 203         if (r < 0)
 204                 return r;
 205
 206         after_cap = cap_dup(before_cap);
 207         if (!after_cap)
 208                 return -errno;
 209
 210         for (unsigned i = 0; i <= cap_last_cap(); i++) {
 211                 cap_value_t v;
 212
 213                 if ((keep & (UINT64_C(1) << i)))
 214                         continue;
 215
 216                 /* Drop it from the bounding set */
 217                 if (prctl(PR_CAPBSET_DROP, i) < 0) {
 218                         r = -errno;
 219
 220                         /* If dropping the capability failed, let's see if we didn't have it in the first place. If so,
 221                          * continue anyway, as dropping a capability we didn't have in the first place doesn't really
 222                          * matter anyway. */
 223                         if (prctl(PR_CAPBSET_READ, i) != 0)
 224                                 goto finish;
 225                 }
 226                 v = (cap_value_t) i;
 227
 228                 /* Also drop it from the inheritable set, so
 229                  * that anything we exec() loses the
 230                  * capability for good. */
 231                 if (cap_set_flag(after_cap, CAP_INHERITABLE, 1, &v, CAP_CLEAR) < 0) {
 232                         r = -errno;
 233                         goto finish;
 234                 }
 235
 236                 /* If we shall apply this right now drop it
 237                  * also from our own capability sets. */
 238                 if (right_now) {
 239                         if (cap_set_flag(after_cap, CAP_PERMITTED, 1, &v, CAP_CLEAR) < 0 ||
 240                             cap_set_flag(after_cap, CAP_EFFECTIVE, 1, &v, CAP_CLEAR) < 0) {
 241                                 r = -errno;
 242                                 goto finish;
 243                         }
 244                 }
 245         }
 246
 247         r = 0;
 248
 249 finish:
 250         if (cap_set_proc(after_cap) < 0) {
 251                 /* If there are no actual changes anyway then let's ignore this error. */
 252                 if (cap_compare(before_cap, after_cap) != 0)
 253                         r = -errno;
 254         }
 255
 256         return r;
 257 }
 258
 259 static int drop_from_file(const char *fn, uint64_t keep) {
 260         _cleanup_free_ char *p = NULL;
 261         uint64_t current, after;
 262         uint32_t hi, lo;
 263         int r, k;
 264
 265         r = read_one_line_file(fn, &p);
 266         if (r < 0)
 267                 return r;
 268
 269         k = sscanf(p, "%" PRIu32 " %" PRIu32, &lo, &hi);
 270         if (k != 2)
 271                 return -EIO;
 272
 273         current = (uint64_t) lo | ((uint64_t) hi << 32);
 274         after = current & keep;
 275
 276         if (current == after)
 277                 return 0;
 278
 279         lo = after & UINT32_MAX;
 280         hi = (after >> 32) & UINT32_MAX;
 281
 282         return write_string_filef(fn, 0, "%" PRIu32 " %" PRIu32, lo, hi);
 283 }
 284
 285 int capability_bounding_set_drop_usermode(uint64_t keep) {
 286         int r;
 287
 288         r = drop_from_file("/proc/sys/kernel/usermodehelper/inheritable", keep);
 289         if (r < 0)
 290                 return r;
 291
 292         r = drop_from_file("/proc/sys/kernel/usermodehelper/bset", keep);
 293         if (r < 0)
 294                 return r;
 295
 296         return r;
 297 }
 298
 299 int drop_privileges(uid_t uid, gid_t gid, uint64_t keep_capabilities) {
 300         int r;
 301
 302         /* Unfortunately we cannot leave privilege dropping to PID 1 here, since we want to run as user but
 303          * want to keep some capabilities. Since file capabilities have been introduced this cannot be done
 304          * across exec() anymore, unless our binary has the capability configured in the file system, which
 305          * we want to avoid. */
 306
 307         if (setresgid(gid, gid, gid) < 0)
 308                 return log_error_errno(errno, "Failed to change group ID: %m");
 309
 310         r = maybe_setgroups(0, NULL);
 311         if (r < 0)
 312                 return log_error_errno(r, "Failed to drop auxiliary groups list: %m");
 313
 314         /* Ensure we keep the permitted caps across the setresuid(). Note that we do this even if we actually
 315          * don't want to keep any capabilities, since we want to be able to drop them from the bounding set
 316          * too, and we can only do that if we have capabilities. */
 317         if (prctl(PR_SET_KEEPCAPS, 1) < 0)
 318                 return log_error_errno(errno, "Failed to enable keep capabilities flag: %m");
 319
 320         if (setresuid(uid, uid, uid) < 0)
 321                 return log_error_errno(errno, "Failed to change user ID: %m");
 322
 323         if (prctl(PR_SET_KEEPCAPS, 0) < 0)
 324                 return log_error_errno(errno, "Failed to disable keep capabilities flag: %m");
 325
 326         /* Drop all caps from the bounding set (as well as the inheritable/permitted/effective sets), except
 327          * the ones we want to keep */
 328         r = capability_bounding_set_drop(keep_capabilities, true);
 329         if (r < 0)
 330                 return log_error_errno(r, "Failed to drop capabilities: %m");
 331
 332         /* Now upgrade the permitted caps we still kept to effective caps */
 333         if (keep_capabilities != 0) {
 334                 cap_value_t bits[log2u64(keep_capabilities) + 1];
 335                 _cleanup_cap_free_ cap_t d = NULL;
 336                 unsigned i, j = 0;
 337
 338                 d = cap_init();
 339                 if (!d)
 340                         return log_oom();
 341
 342                 for (i = 0; i < ELEMENTSOF(bits); i++)
 343                         if (keep_capabilities & (1ULL << i))
 344                                 bits[j++] = i;
 345
 346                 /* use enough bits */
 347                 assert(i == 64 || (keep_capabilities >> i) == 0);
 348                 /* don't use too many bits */
 349                 assert(keep_capabilities & (UINT64_C(1) << (i - 1)));
 350
 351                 if (cap_set_flag(d, CAP_EFFECTIVE, j, bits, CAP_SET) < 0 ||
 352                     cap_set_flag(d, CAP_PERMITTED, j, bits, CAP_SET) < 0)
 353                         return log_error_errno(errno, "Failed to enable capabilities bits: %m");
 354
 355                 if (cap_set_proc(d) < 0)
 356                         return log_error_errno(errno, "Failed to increase capabilities: %m");
 357         }
 358
 359         return 0;
 360 }
 361
 362 static int change_capability(cap_value_t cv, cap_flag_value_t flag) {
 363         _cleanup_cap_free_ cap_t tmp_cap = NULL;
 364
 365         tmp_cap = cap_get_proc();
 366         if (!tmp_cap)
 367                 return -errno;
 368
 369         if ((cap_set_flag(tmp_cap, CAP_INHERITABLE, 1, &cv, flag) < 0) ||
 370             (cap_set_flag(tmp_cap, CAP_PERMITTED, 1, &cv, flag) < 0) ||
 371             (cap_set_flag(tmp_cap, CAP_EFFECTIVE, 1, &cv, flag) < 0))
 372                 return -errno;
 373
 374         if (cap_set_proc(tmp_cap) < 0)
 375                 return -errno;
 376
 377         return 0;
 378 }
 379
 380 int drop_capability(cap_value_t cv) {
 381         return change_capability(cv, CAP_CLEAR);
 382 }
 383
 384 int keep_capability(cap_value_t cv) {
 385         return change_capability(cv, CAP_SET);
 386 }
 387
 388 bool capability_quintet_mangle(CapabilityQuintet *q) {
 389         uint64_t combined, drop = 0;
 390
 391         assert(q);
 392
 393         combined = q->effective | q->bounding | q->inheritable | q->permitted | q->ambient;
 394
 395         for (unsigned i = 0; i <= cap_last_cap(); i++) {
 396                 if (!BIT_SET(combined, i))
 397                         continue;
 398
 399                 if (prctl(PR_CAPBSET_READ, (unsigned long) i) > 0)
 400                         continue;
 401
 402                 SET_BIT(drop, i);
 403
 404                 log_debug("Dropping capability not in the current bounding set: %s", capability_to_name(i));
 405         }
 406
 407         q->effective &= ~drop;
 408         q->bounding &= ~drop;
 409         q->inheritable &= ~drop;
 410         q->permitted &= ~drop;
 411         q->ambient &= ~drop;
 412
 413         return drop != 0; /* Let the caller know we changed something */
 414 }
 415
 416 int capability_quintet_enforce(const CapabilityQuintet *q) {
 417         _cleanup_cap_free_ cap_t c = NULL, modified = NULL;
 418         int r;
 419
 420         if (q->ambient != CAP_MASK_UNSET) {
 421                 bool changed = false;
 422
 423                 c = cap_get_proc();
 424                 if (!c)
 425                         return -errno;
 426
 427                 /* In order to raise the ambient caps set we first need to raise the matching
 428                  * inheritable + permitted cap */
 429                 for (unsigned i = 0; i <= cap_last_cap(); i++) {
 430                         uint64_t m = UINT64_C(1) << i;
 431                         cap_value_t cv = (cap_value_t) i;
 432                         cap_flag_value_t old_value_inheritable, old_value_permitted;
 433
 434                         if ((q->ambient & m) == 0)
 435                                 continue;
 436
 437                         if (cap_get_flag(c, cv, CAP_INHERITABLE, &old_value_inheritable) < 0)
 438                                 return -errno;
 439                         if (cap_get_flag(c, cv, CAP_PERMITTED, &old_value_permitted) < 0)
 440                                 return -errno;
 441
 442                         if (old_value_inheritable == CAP_SET && old_value_permitted == CAP_SET)
 443                                 continue;
 444
 445                         if (cap_set_flag(c, CAP_INHERITABLE, 1, &cv, CAP_SET) < 0)
 446                                 return -errno;
 447                         if (cap_set_flag(c, CAP_PERMITTED, 1, &cv, CAP_SET) < 0)
 448                                 return -errno;
 449
 450                         changed = true;
 451                 }
 452
 453                 if (changed)
 454                         if (cap_set_proc(c) < 0)
 455                                 return -errno;
 456
 457                 r = capability_ambient_set_apply(q->ambient, false);
 458                 if (r < 0)
 459                         return r;
 460         }
 461
 462         if (q->inheritable != CAP_MASK_UNSET || q->permitted != CAP_MASK_UNSET || q->effective != CAP_MASK_UNSET) {
 463                 bool changed = false;
 464
 465                 if (!c) {
 466                         c = cap_get_proc();
 467                         if (!c)
 468                                 return -errno;
 469                 }
 470
 471                 for (unsigned i = 0; i <= cap_last_cap(); i++) {
 472                         uint64_t m = UINT64_C(1) << i;
 473                         cap_value_t cv = (cap_value_t) i;
 474
 475                         if (q->inheritable != CAP_MASK_UNSET) {
 476                                 cap_flag_value_t old_value, new_value;
 477
 478                                 if (cap_get_flag(c, cv, CAP_INHERITABLE, &old_value) < 0) {
 479                                         if (errno == EINVAL) /* If the kernel knows more caps than this
 480                                                               * version of libcap, then this will return
 481                                                               * EINVAL. In that case, simply ignore it,
 482                                                               * pretend it doesn't exist. */
 483                                                 continue;
 484
 485                                         return -errno;
 486                                 }
 487
 488                                 new_value = (q->inheritable & m) ? CAP_SET : CAP_CLEAR;
 489
 490                                 if (old_value != new_value) {
 491                                         changed = true;
 492
 493                                         if (cap_set_flag(c, CAP_INHERITABLE, 1, &cv, new_value) < 0)
 494                                                 return -errno;
 495                                 }
 496                         }
 497
 498                         if (q->permitted != CAP_MASK_UNSET) {
 499                                 cap_flag_value_t old_value, new_value;
 500
 501                                 if (cap_get_flag(c, cv, CAP_PERMITTED, &old_value) < 0) {
 502                                         if (errno == EINVAL)
 503                                                 continue;
 504
 505                                         return -errno;
 506                                 }
 507
 508                                 new_value = (q->permitted & m) ? CAP_SET : CAP_CLEAR;
 509
 510                                 if (old_value != new_value) {
 511                                         changed = true;
 512
 513                                         if (cap_set_flag(c, CAP_PERMITTED, 1, &cv, new_value) < 0)
 514                                                 return -errno;
 515                                 }
 516                         }
 517
 518                         if (q->effective != CAP_MASK_UNSET) {
 519                                 cap_flag_value_t old_value, new_value;
 520
 521                                 if (cap_get_flag(c, cv, CAP_EFFECTIVE, &old_value) < 0) {
 522                                         if (errno == EINVAL)
 523                                                 continue;
 524
 525                                         return -errno;
 526                                 }
 527
 528                                 new_value = (q->effective & m) ? CAP_SET : CAP_CLEAR;
 529
 530                                 if (old_value != new_value) {
 531                                         changed = true;
 532
 533                                         if (cap_set_flag(c, CAP_EFFECTIVE, 1, &cv, new_value) < 0)
 534                                                 return -errno;
 535                                 }
 536                         }
 537                 }
 538
 539                 if (changed) {
 540                         /* In order to change the bounding caps, we need to keep CAP_SETPCAP for a bit
 541                          * longer. Let's add it to our list hence for now. */
 542                         if (q->bounding != CAP_MASK_UNSET) {
 543                                 cap_value_t cv = CAP_SETPCAP;
 544
 545                                 modified = cap_dup(c);
 546                                 if (!modified)
 547                                         return -ENOMEM;
 548
 549                                 if (cap_set_flag(modified, CAP_PERMITTED, 1, &cv, CAP_SET) < 0)
 550                                         return -errno;
 551                                 if (cap_set_flag(modified, CAP_EFFECTIVE, 1, &cv, CAP_SET) < 0)
 552                                         return -errno;
 553
 554                                 if (cap_compare(modified, c) == 0) {
 555                                         /* No change? then drop this nonsense again */
 556                                         cap_free(modified);
 557                                         modified = NULL;
 558                                 }
 559                         }
 560
 561                         /* Now, let's enforce the caps for the first time. Note that this is where we acquire
 562                          * caps in any of the sets we currently don't have. We have to do this before
 563                          * dropping the bounding caps below, since at that point we can never acquire new
 564                          * caps in inherited/permitted/effective anymore, but only lose them. */
 565                         if (cap_set_proc(modified ?: c) < 0)
 566                                 return -errno;
 567                 }
 568         }
 569
 570         if (q->bounding != CAP_MASK_UNSET) {
 571                 r = capability_bounding_set_drop(q->bounding, false);
 572                 if (r < 0)
 573                         return r;
 574         }
 575
 576         /* If needed, let's now set the caps again, this time in the final version, which differs from what
 577          * we have already set only in the CAP_SETPCAP bit, which we needed for dropping the bounding
 578          * bits. This call only undoes bits and doesn't acquire any which means the bounding caps don't
 579          * matter. */
 580         if (modified)
 581                 if (cap_set_proc(c) < 0)
 582                         return -errno;
 583
 584         return 0;
 585 }
 586
 587 int capability_get_ambient(uint64_t *ret) {
 588         uint64_t a = 0;
 589         int r;
 590
 591         assert(ret);
 592
 593         for (unsigned i = 0; i <= cap_last_cap(); i++) {
 594                 r = prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, i, 0, 0);
 595                 if (r < 0)
 596                         return -errno;
 597                 if (r > 0)
 598                         SET_BIT(a, i);
 599         }
 600
 601         *ret = a;
 602         return 1;
 603 }
 604
 605 int pidref_get_capability(const PidRef *pidref, CapabilityQuintet *ret) {
 606         int r;
 607
 608         if (!pidref_is_set(pidref))
 609                 return -ESRCH;
 610         if (pidref_is_remote(pidref))
 611                 return -EREMOTE;
 612
 613         const char *path = procfs_file_alloca(pidref->pid, "status");
 614         _cleanup_fclose_ FILE *f = fopen(path, "re");
 615         if (!f) {
 616                 if (errno == ENOENT && proc_mounted() == 0)
 617                         return -ENOSYS;
 618
 619                 return -errno;
 620         }
 621
 622         CapabilityQuintet q = CAPABILITY_QUINTET_NULL;
 623         for (;;) {
 624                 _cleanup_free_ char *line = NULL;
 625
 626                 r = read_line(f, LONG_LINE_MAX, &line);
 627                 if (r < 0)
 628                         return r;
 629                 if (r == 0)
 630                         break;
 631
 632                 static const struct {
 633                         const char *field;
 634                         size_t offset;
 635                 } fields[] = {
 636                         { "CapBnd:", offsetof(CapabilityQuintet, bounding)    },
 637                         { "CapInh:", offsetof(CapabilityQuintet, inheritable) },
 638                         { "CapPrm:", offsetof(CapabilityQuintet, permitted)   },
 639                         { "CapEff:", offsetof(CapabilityQuintet, effective)   },
 640                         { "CapAmb:", offsetof(CapabilityQuintet, ambient)     },
 641                 };
 642
 643                 FOREACH_ELEMENT(i, fields) {
 644
 645                         const char *p = first_word(line, i->field);
 646                         if (!p)
 647                                 continue;
 648
 649                         uint64_t *v = (uint64_t*) ((uint8_t*) &q + i->offset);
 650
 651                         if (*v != CAP_MASK_UNSET)
 652                                 return -EBADMSG;
 653
 654                         r = safe_atoux64(p, v);
 655                         if (r < 0)
 656                                 return r;
 657
 658                         if (*v == CAP_MASK_UNSET)
 659                                 return -EBADMSG;
 660                 }
 661         }
 662
 663         if (!capability_quintet_is_fully_set(&q))
 664                 return -EBADMSG;
 665
 666         r = pidref_verify(pidref);
 667         if (r < 0)
 668                 return r;
 669
 670         if (ret)
 671                 *ret = q;
 672
 673         return 0;
 674 }