src/afs/LINUX/osi_groups.c

   1 /*
   2  * Copyright 2000, International Business Machines Corporation and others.
   3  * All Rights Reserved.
   4  *
   5  * This software has been released under the terms of the IBM Public
   6  * License.  For details, see the LICENSE file in the top-level source
   7  * directory or online at http://www.openafs.org/dl/license10.html
   8  */
   9
  10 /*
  11  * Implements:
  12  * setgroups (syscall)
  13  * setpag
  14  *
  15  */
  16 #include <afsconfig.h>
  17 #include "afs/param.h"
  18 #ifdef LINUX_KEYRING_SUPPORT
  19 #include <linux/seq_file.h>
  20 #endif
  21
  22
  23 #include "afs/sysincludes.h"
  24 #include "afsincludes.h"
  25 #include "afs/afs_stats.h"      /* statistics */
  26 #include "afs/nfsclient.h"
  27 #include "osi_compat.h"
  28
  29 #ifdef AFS_PAG_ONEGROUP_ENV
  30
  31 static afs_uint32
  32 afs_linux_pag_from_groups(struct group_info *group_info) {
  33     afs_uint32 g0 = 0;
  34     afs_uint32 i;
  35
  36     if (group_info->ngroups < AFS_NUMPAGGROUPS)
  37         return NOPAG;
  38
  39     for (i = 0; i < group_info->ngroups; i++) {
  40         g0 = afs_from_kgid(GROUP_AT(group_info, i));
  41         if (((g0 >> 24) & 0xff) == 'A')
  42             return g0;
  43     }
  44     return NOPAG;
  45 }
  46
  47 static inline void
  48 afs_linux_pag_to_groups(afs_uint32 newpag,
  49                         struct group_info *old, struct group_info **new) {
  50     int need_space = 0;
  51     int i;
  52     int j;
  53     afs_kgid_t newkgid = afs_make_kgid(newpag);
  54
  55     if (afs_linux_pag_from_groups(old) == NOPAG)
  56         need_space = AFS_NUMPAGGROUPS;
  57
  58     *new = groups_alloc(old->ngroups + need_space);
  59
  60     for (i = 0, j = 0; i < old->ngroups; ++i) {
  61         afs_kgid_t ths = GROUP_AT(old, i);
  62         if ((afs_from_kgid(ths) >> 24) == 'A')
  63             continue;
  64         if ((i == 0 || !gid_lt(newkgid, GROUP_AT(old, i-1))) &&
  65             gid_lt(newkgid, ths)) {
  66            GROUP_AT(*new, j) = newkgid;
  67            j++;
  68         }
  69         GROUP_AT(*new, j) = ths;
  70         j++;
  71     }
  72     if (j != i + need_space)
  73         GROUP_AT(*new, j) = newkgid;
  74 }
  75
  76 #else
  77
  78 static inline afs_uint32
  79 afs_linux_pag_from_groups(struct group_info *group_info) {
  80
  81     if (group_info->ngroups < AFS_NUMPAGGROUPS)
  82         return NOPAG;
  83
  84     return afs_get_pag_from_groups(GROUP_AT(group_info, 0), GROUP_AT(group_info, 1));
  85 }
  86
  87 static inline void
  88 afs_linux_pag_to_groups(afs_uint32 newpag,
  89                         struct group_info *old, struct group_info **new) {
  90     int need_space = 0;
  91     int i;
  92     gid_t g0;
  93     gid_t g1;
  94
  95     if (afs_linux_pag_from_groups(old) == NOPAG)
  96         need_space = AFS_NUMPAGGROUPS;
  97
  98     *new = groups_alloc(old->ngroups + need_space);
  99
 100     for (i = 0; i < old->ngroups; ++i)
 101           GROUP_AT(new, i + need_space) = GROUP_AT(old, i);
 102
 103     afs_get_groups_from_pag(newpag, &g0, g1);
 104     GROUP_AT(new, 0) = g0;
 105     GROUP_AT(new, 1) = g1;
 106 }
 107 #endif
 108
 109 afs_int32
 110 osi_get_group_pag(afs_ucred_t *cred) {
 111     return afs_linux_pag_from_groups(afs_cr_group_info(cred));
 112 }
 113
 114
 115 static int
 116 afs_setgroups(cred_t **cr, struct group_info *group_info, int change_parent)
 117 {
 118     struct group_info *old_info;
 119
 120     AFS_STATCNT(afs_setgroups);
 121
 122     old_info = afs_cr_group_info(*cr);
 123     get_group_info(group_info);
 124     afs_set_cr_group_info(*cr, group_info);
 125     put_group_info(old_info);
 126
 127     crset(*cr);
 128
 129 #if defined(STRUCT_TASK_STRUCT_HAS_PARENT) && !defined(STRUCT_TASK_STRUCT_HAS_CRED)
 130     if (change_parent) {
 131         old_info = current->parent->group_info;
 132         get_group_info(group_info);
 133         current->parent->group_info = group_info;
 134         put_group_info(old_info);
 135     }
 136 #endif
 137
 138     return (0);
 139 }
 140
 141 int
 142 __setpag(cred_t **cr, afs_uint32 pagvalue, afs_uint32 *newpag,
 143          int change_parent, struct group_info **old_groups)
 144 {
 145     struct group_info *group_info;
 146     struct group_info *tmp;
 147
 148     get_group_info(afs_cr_group_info(*cr));
 149     group_info = afs_cr_group_info(*cr);
 150
 151     *newpag = (pagvalue == -1 ? genpag() : pagvalue);
 152     afs_linux_pag_to_groups(*newpag, group_info, &tmp);
 153
 154     if (old_groups) {
 155         *old_groups = group_info;
 156     } else {
 157         put_group_info(group_info);
 158         group_info = NULL;
 159     }
 160
 161     afs_setgroups(cr, tmp, change_parent);
 162
 163     put_group_info(tmp);
 164
 165     return 0;
 166 }
 167
 168 #ifdef LINUX_KEYRING_SUPPORT
 169 extern struct key_type key_type_keyring __attribute__((weak));
 170 static struct key_type *__key_type_keyring = &key_type_keyring;
 171
 172 /* install_session_keyring returns negative error values */
 173 static int
 174 install_session_keyring(struct key *keyring)
 175 {
 176     struct key *old;
 177     char desc[20];
 178     int code = -EINVAL;
 179     unsigned long flags;
 180
 181     if (!__key_type_keyring)
 182         return code;
 183
 184     if (!keyring) {
 185
 186         /* create an empty session keyring */
 187         sprintf(desc, "_ses.%u", current->tgid);
 188
 189         /* if we're root, don't count the keyring against our quota. This
 190          * avoids starvation issues when dealing with PAM modules that always
 191          * setpag() as root */
 192         if (capable(CAP_SYS_ADMIN))
 193             flags = KEY_ALLOC_NOT_IN_QUOTA;
 194         else
 195             flags = KEY_ALLOC_IN_QUOTA;
 196
 197         keyring = afs_linux_key_alloc(
 198                             __key_type_keyring, desc,
 199                             current_uid(), current_gid(),
 200                             (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL,
 201                             flags);
 202
 203         if (IS_ERR(keyring)) {
 204             code = PTR_ERR(keyring);
 205             goto out;
 206         }
 207     }
 208
 209     code = key_instantiate_and_link(keyring, NULL, 0, NULL, NULL);
 210     if (code < 0) {
 211         key_put(keyring);
 212         goto out;
 213     }
 214
 215     /* install the keyring */
 216     old = afs_set_session_keyring(keyring);
 217     if (old)
 218         key_put(old);
 219
 220 out:
 221     return code;
 222 }
 223 #endif /* LINUX_KEYRING_SUPPORT */
 224
 225 /* Error codes from setpag must be positive, otherwise they don't
 226  * make it back into userspace properly. Error codes from the
 227  * Linux keyring utilities, and from install_session_keyring()
 228  * are negative. So we need to be careful to convert them correctly
 229  * here
 230  */
 231 int
 232 setpag(cred_t **cr, afs_uint32 pagvalue, afs_uint32 *newpag,
 233        int change_parent)
 234 {
 235     int code;
 236     struct group_info *old_groups = NULL;
 237
 238     AFS_STATCNT(setpag);
 239
 240     code = __setpag(cr, pagvalue, newpag, change_parent, &old_groups);
 241
 242 #ifdef LINUX_KEYRING_SUPPORT
 243     if (code == 0 && afs_cr_rgid(*cr) != NFSXLATOR_CRED) {
 244         code = install_session_keyring(NULL);
 245         if (code == 0 && current_session_keyring()) {
 246             struct key *key;
 247             key_perm_t perm;
 248
 249             perm = KEY_POS_VIEW | KEY_POS_SEARCH;
 250             perm |= KEY_USR_VIEW | KEY_USR_SEARCH;
 251
 252             key = afs_linux_key_alloc(&key_type_afs_pag, "_pag", GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, perm, KEY_ALLOC_NOT_IN_QUOTA);
 253
 254             if (!IS_ERR(key)) {
 255                 code = key_instantiate_and_link(key, (void *) newpag, sizeof(afs_uint32),
 256                                          current_session_keyring(), NULL);
 257                 key_put(key);
 258             } else {
 259                 code = PTR_ERR(key);
 260             }
 261         }
 262         if (code)
 263             code = -code;
 264     }
 265 #endif /* LINUX_KEYRING_SUPPORT */
 266
 267     if (code) {
 268         if (old_groups) {
 269             afs_setgroups(cr, old_groups, change_parent);
 270             put_group_info(old_groups);
 271             old_groups = NULL;
 272         }
 273         if (*newpag > -1) {
 274             afs_MarkUserExpired(*newpag);
 275             *newpag = -1;
 276         }
 277     }
 278
 279     return code;
 280 }
 281
 282 #ifndef LINUX_KEYRING_SUPPORT
 283 /* Intercept the standard system call. */
 284 extern asmlinkage long (*sys_setgroupsp) (int gidsetsize, gid_t * grouplist);
 285 asmlinkage long
 286 afs_xsetgroups(int gidsetsize, gid_t * grouplist)
 287 {
 288     long code;
 289     cred_t *cr = crref();
 290     afs_uint32 junk;
 291     int old_pag;
 292
 293     old_pag = PagInCred(cr);
 294     crfree(cr);
 295
 296     code = (*sys_setgroupsp) (gidsetsize, grouplist);
 297     if (code) {
 298         return code;
 299     }
 300
 301     cr = crref();
 302     if (old_pag != NOPAG && PagInCred(cr) == NOPAG) {
 303         /* re-install old pag if there's room. */
 304         code = __setpag(&cr, old_pag, &junk, 0, NULL);
 305     }
 306     crfree(cr);
 307
 308     /* Linux syscall ABI returns errno as negative */
 309     return (-code);
 310 }
 311
 312 /* Intercept the standard uid32 system call. */
 313 extern asmlinkage int (*sys_setgroups32p) (int gidsetsize,
 314                                            __kernel_gid32_t * grouplist);
 315 asmlinkage long
 316 afs_xsetgroups32(int gidsetsize, gid_t * grouplist)
 317 {
 318     long code;
 319     cred_t *cr = crref();
 320     afs_uint32 junk;
 321     int old_pag;
 322
 323     old_pag = PagInCred(cr);
 324     crfree(cr);
 325
 326     code = (*sys_setgroups32p) (gidsetsize, grouplist);
 327
 328     if (code) {
 329         return code;
 330     }
 331
 332     cr = crref();
 333     if (old_pag != NOPAG && PagInCred(cr) == NOPAG) {
 334         /* re-install old pag if there's room. */
 335         code = __setpag(&cr, old_pag, &junk, 0, NULL);
 336     }
 337     crfree(cr);
 338
 339     /* Linux syscall ABI returns errno as negative */
 340     return (-code);
 341 }
 342
 343 # if defined(AFS_PPC64_LINUX20_ENV)
 344 /* Intercept the uid16 system call as used by 32bit programs. */
 345 extern asmlinkage long (*sys32_setgroupsp)(int gidsetsize, gid_t *grouplist);
 346 asmlinkage long afs32_xsetgroups(int gidsetsize, gid_t *grouplist)
 347 {
 348     long code;
 349     cred_t *cr = crref();
 350     afs_uint32 junk;
 351     int old_pag;
 352
 353     old_pag = PagInCred(cr);
 354     crfree(cr);
 355
 356     code = (*sys32_setgroupsp)(gidsetsize, grouplist);
 357     if (code) {
 358         return code;
 359     }
 360
 361     cr = crref();
 362     if (old_pag != NOPAG && PagInCred(cr) == NOPAG) {
 363         /* re-install old pag if there's room. */
 364         code = __setpag(&cr, old_pag, &junk, 0, NULL);
 365     }
 366     crfree(cr);
 367
 368     /* Linux syscall ABI returns errno as negative */
 369     return (-code);
 370 }
 371 # endif
 372
 373 # if defined(AFS_SPARC64_LINUX20_ENV) || defined(AFS_AMD64_LINUX20_ENV)
 374 /* Intercept the uid16 system call as used by 32bit programs. */
 375 #  ifdef AFS_AMD64_LINUX20_ENV
 376 extern asmlinkage long (*sys32_setgroupsp) (int gidsetsize, u16 * grouplist);
 377 #  endif /* AFS_AMD64_LINUX20_ENV */
 378 #  ifdef AFS_SPARC64_LINUX26_ENV
 379 extern asmlinkage int (*sys32_setgroupsp) (int gidsetsize,
 380                                            __kernel_gid32_t * grouplist);
 381 #  endif /* AFS_SPARC64_LINUX26_ENV */
 382 asmlinkage long
 383 afs32_xsetgroups(int gidsetsize, u16 * grouplist)
 384 {
 385     long code;
 386     cred_t *cr = crref();
 387     afs_uint32 junk;
 388     int old_pag;
 389
 390     old_pag = PagInCred(cr);
 391     crfree(cr);
 392
 393     code = (*sys32_setgroupsp) (gidsetsize, grouplist);
 394     if (code) {
 395         return code;
 396     }
 397
 398     cr = crref();
 399     if (old_pag != NOPAG && PagInCred(cr) == NOPAG) {
 400         /* re-install old pag if there's room. */
 401         code = __setpag(&cr, old_pag, &junk, 0, NULL);
 402     }
 403     crfree(cr);
 404
 405     /* Linux syscall ABI returns errno as negative */
 406     return (-code);
 407 }
 408
 409 /* Intercept the uid32 system call as used by 32bit programs. */
 410 #  ifdef AFS_AMD64_LINUX20_ENV
 411 extern asmlinkage long (*sys32_setgroups32p) (int gidsetsize, gid_t * grouplist);
 412 #  endif /* AFS_AMD64_LINUX20_ENV */
 413 #  ifdef AFS_SPARC64_LINUX26_ENV
 414 extern asmlinkage int (*sys32_setgroups32p) (int gidsetsize,
 415                                              __kernel_gid32_t * grouplist);
 416 #  endif /* AFS_SPARC64_LINUX26_ENV */
 417 asmlinkage long
 418 afs32_xsetgroups32(int gidsetsize, gid_t * grouplist)
 419 {
 420     long code;
 421     cred_t *cr = crref();
 422     afs_uint32 junk;
 423     int old_pag;
 424
 425     old_pag = PagInCred(cr);
 426     crfree(cr);
 427
 428     code = (*sys32_setgroups32p) (gidsetsize, grouplist);
 429     if (code) {
 430         return code;
 431     }
 432
 433     cr = crref();
 434     if (old_pag != NOPAG && PagInCred(cr) == NOPAG) {
 435         /* re-install old pag if there's room. */
 436         code = __setpag(&cr, old_pag, &junk, 0, NULL);
 437     }
 438     crfree(cr);
 439
 440     /* Linux syscall ABI returns errno as negative */
 441     return (-code);
 442 }
 443 # endif
 444 #endif /* !LINUX_KEYRING_SUPPORT */
 445
 446 #ifdef LINUX_KEYRING_SUPPORT
 447 static void afs_pag_describe(const struct key *key, struct seq_file *m)
 448 {
 449     seq_puts(m, key->description);
 450
 451     seq_printf(m, ": %u", key->datalen);
 452 }
 453
 454 #if defined(STRUCT_KEY_TYPE_HAS_PREPARSE)
 455 static int afs_pag_instantiate(struct key *key, struct key_preparsed_payload *prep)
 456 #else
 457 static int afs_pag_instantiate(struct key *key, const void *data, size_t datalen)
 458 #endif
 459 {
 460     int code;
 461     afs_uint32 *userpag, pag = NOPAG;
 462
 463     if (!uid_eq(key->uid, GLOBAL_ROOT_UID) || !gid_eq(key->gid, GLOBAL_ROOT_GID))
 464         return -EPERM;
 465
 466     code = -EINVAL;
 467     get_group_info(current_group_info());
 468
 469 #if defined(STRUCT_KEY_TYPE_HAS_PREPARSE)
 470     if (prep->datalen != sizeof(afs_uint32) || !prep->data)
 471 #else
 472     if (datalen != sizeof(afs_uint32) || !data)
 473 #endif
 474         goto error;
 475
 476     /* ensure key being set matches current pag */
 477     pag = afs_linux_pag_from_groups(current_group_info());
 478
 479     if (pag == NOPAG)
 480         goto error;
 481
 482 #if defined(STRUCT_KEY_TYPE_HAS_PREPARSE)
 483     userpag = (afs_uint32 *)prep->data;
 484 #else
 485     userpag = (afs_uint32 *)data;
 486 #endif
 487     if (*userpag != pag)
 488         goto error;
 489
 490 #if defined(STRUCT_KEY_HAS_PAYLOAD_VALUE)
 491     key->payload.value = (unsigned long) *userpag;
 492 #else
 493     memcpy(&key->payload, userpag, sizeof(afs_uint32));
 494 #endif
 495     key->datalen = sizeof(afs_uint32);
 496     code = 0;
 497
 498 error:
 499     put_group_info(current_group_info());
 500     return code;
 501 }
 502
 503 #if !defined(STRUCT_KEY_TYPE_HAS_MATCH_PREPARSE)
 504 /* Note that we only define a ->match function if struct
 505  * key_type.match_preparse does _not_ exist. If key_type.match_preparse does
 506  * exist, we would use that to specify an alternative comparison function; but
 507  * since we just rely on default behavior, we don't need to actually specify
 508  * one. But for kernels with no such match_preparse function, we need to
 509  * specify a 'match' function, since there is no default. */
 510 static int afs_pag_match(const struct key *key, const void *description)
 511 {
 512         return strcmp(key->description, description) == 0;
 513 }
 514 #endif
 515
 516 static void afs_pag_destroy(struct key *key)
 517 {
 518     afs_uint32 pag;
 519     int locked = ISAFS_GLOCK();
 520
 521 #if defined(STRUCT_KEY_HAS_PAYLOAD_VALUE)
 522     pag = key->payload.value;
 523 #else
 524     memcpy(&pag, &key->payload, sizeof(afs_uint32));
 525 #endif
 526
 527     if (!locked)
 528         AFS_GLOCK();
 529
 530     afs_MarkUserExpired(pag);
 531
 532     if (!locked)
 533         AFS_GUNLOCK();
 534 }
 535
 536 struct key_type key_type_afs_pag =
 537 {
 538     .name        = "afs_pag",
 539     .describe    = afs_pag_describe,
 540 #if defined(STRUCT_KEY_TYPE_HAS_INSTANTIATE_PREP)
 541     .instantiate_prep = afs_pag_instantiate,
 542     .instantiate = NULL,
 543 #else
 544     .instantiate = afs_pag_instantiate,
 545 #endif
 546 #if !defined(STRUCT_KEY_TYPE_HAS_MATCH_PREPARSE)
 547     .match       = afs_pag_match,
 548 #endif
 549     .destroy     = afs_pag_destroy,
 550 };
 551
 552 #ifdef EXPORTED_TASKLIST_LOCK
 553 extern rwlock_t tasklist_lock __attribute__((weak));
 554 #endif
 555
 556 void osi_keyring_init(void)
 557 {
 558 #if !defined(EXPORTED_KEY_TYPE_KEYRING)
 559     struct task_struct *p;
 560
 561     /* If we can't lock the tasklist, either with its explicit lock,
 562      * or by using the RCU lock, then we can't safely work out the
 563      * type of a keyring. So, we have to rely on the weak reference.
 564      * If that's not available, then keyring based PAGs won't work.
 565      */
 566
 567 #if defined(EXPORTED_TASKLIST_LOCK) || (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16) && defined(HAVE_LINUX_RCU_READ_LOCK))
 568     if (__key_type_keyring == NULL) {
 569 # ifdef EXPORTED_TASKLIST_LOCK
 570         if (&tasklist_lock)
 571             read_lock(&tasklist_lock);
 572 # endif
 573 # if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16) && defined(HAVE_LINUX_RCU_READ_LOCK))
 574 #  ifdef EXPORTED_TASKLIST_LOCK
 575         else
 576 #  endif
 577             rcu_read_lock();
 578 # endif
 579 #if defined(HAVE_LINUX_FIND_TASK_BY_PID)
 580         p = find_task_by_pid(1);
 581 #else
 582         p = find_task_by_vpid(1);
 583 #endif
 584         if (p && task_user(p)->session_keyring)
 585             __key_type_keyring = task_user(p)->session_keyring->type;
 586 # ifdef EXPORTED_TASKLIST_LOCK
 587         if (&tasklist_lock)
 588             read_unlock(&tasklist_lock);
 589 # endif
 590 # if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16) && defined(HAVE_LINUX_RCU_READ_LOCK))
 591 #  ifdef EXPORTED_TASKLIST_LOCK
 592         else
 593 #  endif
 594             rcu_read_unlock();
 595 # endif
 596     }
 597 #endif
 598 #endif
 599
 600     register_key_type(&key_type_afs_pag);
 601 }
 602
 603 void osi_keyring_shutdown(void)
 604 {
 605     unregister_key_type(&key_type_afs_pag);
 606 }
 607
 608 afs_int32
 609 osi_get_keyring_pag(afs_ucred_t *cred)
 610 {
 611     struct key *key;
 612     afs_uint32 newpag;
 613     afs_int32 keyring_pag = NOPAG;
 614
 615     if (afs_cr_rgid(cred) != NFSXLATOR_CRED) {
 616         key = afs_linux_search_keyring(cred, &key_type_afs_pag);
 617
 618         if (!IS_ERR(key)) {
 619             if (key_validate(key) == 0 && uid_eq(key->uid, GLOBAL_ROOT_UID)) {      /* also verify in the session keyring? */
 620 #if defined(STRUCT_KEY_HAS_PAYLOAD_VALUE)
 621                 keyring_pag = key->payload.value;
 622 #else
 623                 memcpy(&keyring_pag, &key->payload, sizeof(afs_int32));
 624 #endif
 625                 /* Only set PAG in groups if needed,
 626                  * and the creds are from the current process */
 627                 if (afs_linux_cred_is_current(cred) &&
 628                     ((keyring_pag >> 24) & 0xff) == 'A' &&
 629                     keyring_pag != afs_linux_pag_from_groups(current_group_info())) {
 630                         __setpag(&cred, keyring_pag, &newpag, 0, NULL);
 631                 }
 632             }
 633             key_put(key);
 634         }
 635     }
 636     return keyring_pag;
 637 }
 638
 639 #else
 640 void osi_keyring_init(void)
 641 {
 642         return;
 643 }
 644
 645 void osi_keyring_shutdown(void)
 646 {
 647         return;
 648 }
 649 #endif