security/selinux/ss/services.c

   1 /*
   2  * Implementation of the security services.
   3  *
   4  * Authors : Stephen Smalley, <sds@epoch.ncsc.mil>
   5  *           James Morris <jmorris@redhat.com>
   6  *
   7  * Updated: Trusted Computer Solutions, Inc. <dgoeddel@trustedcs.com>
   8  *
   9  *      Support for enhanced MLS infrastructure.
  10  *      Support for context based audit filters.
  11  *
  12  * Updated: Frank Mayer <mayerf@tresys.com> and Karl MacMillan <kmacmillan@tresys.com>
  13  *
  14  *      Added conditional policy language extensions
  15  *
  16  * Updated: Hewlett-Packard <paul.moore@hp.com>
  17  *
  18  *      Added support for NetLabel
  19  *      Added support for the policy capability bitmap
  20  *
  21  * Updated: Chad Sellers <csellers@tresys.com>
  22  *
  23  *  Added validation of kernel classes and permissions
  24  *
  25  * Copyright (C) 2006, 2007 Hewlett-Packard Development Company, L.P.
  26  * Copyright (C) 2004-2006 Trusted Computer Solutions, Inc.
  27  * Copyright (C) 2003 - 2004, 2006 Tresys Technology, LLC
  28  * Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
  29  *      This program is free software; you can redistribute it and/or modify
  30  *      it under the terms of the GNU General Public License as published by
  31  *      the Free Software Foundation, version 2.
  32  */
  33 #include <linux/kernel.h>
  34 #include <linux/slab.h>
  35 #include <linux/string.h>
  36 #include <linux/spinlock.h>
  37 #include <linux/rcupdate.h>
  38 #include <linux/errno.h>
  39 #include <linux/in.h>
  40 #include <linux/sched.h>
  41 #include <linux/audit.h>
  42 #include <linux/mutex.h>
  43 #include <linux/selinux.h>
  44 #include <net/netlabel.h>
  45
  46 #include "flask.h"
  47 #include "avc.h"
  48 #include "avc_ss.h"
  49 #include "security.h"
  50 #include "context.h"
  51 #include "policydb.h"
  52 #include "sidtab.h"
  53 #include "services.h"
  54 #include "conditional.h"
  55 #include "mls.h"
  56 #include "objsec.h"
  57 #include "netlabel.h"
  58 #include "xfrm.h"
  59 #include "ebitmap.h"
  60 #include "audit.h"
  61
  62 extern void selnl_notify_policyload(u32 seqno);
  63 unsigned int policydb_loaded_version;
  64
  65 int selinux_policycap_netpeer;
  66 int selinux_policycap_openperm;
  67
  68 /*
  69  * This is declared in avc.c
  70  */
  71 extern const struct selinux_class_perm selinux_class_perm;
  72
  73 static DEFINE_RWLOCK(policy_rwlock);
  74 #define POLICY_RDLOCK read_lock(&policy_rwlock)
  75 #define POLICY_WRLOCK write_lock_irq(&policy_rwlock)
  76 #define POLICY_RDUNLOCK read_unlock(&policy_rwlock)
  77 #define POLICY_WRUNLOCK write_unlock_irq(&policy_rwlock)
  78
  79 static DEFINE_MUTEX(load_mutex);
  80 #define LOAD_LOCK mutex_lock(&load_mutex)
  81 #define LOAD_UNLOCK mutex_unlock(&load_mutex)
  82
  83 static struct sidtab sidtab;
  84 struct policydb policydb;
  85 int ss_initialized;
  86
  87 /*
  88  * The largest sequence number that has been used when
  89  * providing an access decision to the access vector cache.
  90  * The sequence number only changes when a policy change
  91  * occurs.
  92  */
  93 static u32 latest_granting;
  94
  95 /* Forward declaration. */
  96 static int context_struct_to_string(struct context *context, char **scontext,
  97                                     u32 *scontext_len);
  98
  99 /*
 100  * Return the boolean value of a constraint expression
 101  * when it is applied to the specified source and target
 102  * security contexts.
 103  *
 104  * xcontext is a special beast...  It is used by the validatetrans rules
 105  * only.  For these rules, scontext is the context before the transition,
 106  * tcontext is the context after the transition, and xcontext is the context
 107  * of the process performing the transition.  All other callers of
 108  * constraint_expr_eval should pass in NULL for xcontext.
 109  */
 110 static int constraint_expr_eval(struct context *scontext,
 111                                 struct context *tcontext,
 112                                 struct context *xcontext,
 113                                 struct constraint_expr *cexpr)
 114 {
 115         u32 val1, val2;
 116         struct context *c;
 117         struct role_datum *r1, *r2;
 118         struct mls_level *l1, *l2;
 119         struct constraint_expr *e;
 120         int s[CEXPR_MAXDEPTH];
 121         int sp = -1;
 122
 123         for (e = cexpr; e; e = e->next) {
 124                 switch (e->expr_type) {
 125                 case CEXPR_NOT:
 126                         BUG_ON(sp < 0);
 127                         s[sp] = !s[sp];
 128                         break;
 129                 case CEXPR_AND:
 130                         BUG_ON(sp < 1);
 131                         sp--;
 132                         s[sp] &= s[sp+1];
 133                         break;
 134                 case CEXPR_OR:
 135                         BUG_ON(sp < 1);
 136                         sp--;
 137                         s[sp] |= s[sp+1];
 138                         break;
 139                 case CEXPR_ATTR:
 140                         if (sp == (CEXPR_MAXDEPTH-1))
 141                                 return 0;
 142                         switch (e->attr) {
 143                         case CEXPR_USER:
 144                                 val1 = scontext->user;
 145                                 val2 = tcontext->user;
 146                                 break;
 147                         case CEXPR_TYPE:
 148                                 val1 = scontext->type;
 149                                 val2 = tcontext->type;
 150                                 break;
 151                         case CEXPR_ROLE:
 152                                 val1 = scontext->role;
 153                                 val2 = tcontext->role;
 154                                 r1 = policydb.role_val_to_struct[val1 - 1];
 155                                 r2 = policydb.role_val_to_struct[val2 - 1];
 156                                 switch (e->op) {
 157                                 case CEXPR_DOM:
 158                                         s[++sp] = ebitmap_get_bit(&r1->dominates,
 159                                                                   val2 - 1);
 160                                         continue;
 161                                 case CEXPR_DOMBY:
 162                                         s[++sp] = ebitmap_get_bit(&r2->dominates,
 163                                                                   val1 - 1);
 164                                         continue;
 165                                 case CEXPR_INCOMP:
 166                                         s[++sp] = (!ebitmap_get_bit(&r1->dominates,
 167                                                                     val2 - 1) &&
 168                                                    !ebitmap_get_bit(&r2->dominates,
 169                                                                     val1 - 1));
 170                                         continue;
 171                                 default:
 172                                         break;
 173                                 }
 174                                 break;
 175                         case CEXPR_L1L2:
 176                                 l1 = &(scontext->range.level[0]);
 177                                 l2 = &(tcontext->range.level[0]);
 178                                 goto mls_ops;
 179                         case CEXPR_L1H2:
 180                                 l1 = &(scontext->range.level[0]);
 181                                 l2 = &(tcontext->range.level[1]);
 182                                 goto mls_ops;
 183                         case CEXPR_H1L2:
 184                                 l1 = &(scontext->range.level[1]);
 185                                 l2 = &(tcontext->range.level[0]);
 186                                 goto mls_ops;
 187                         case CEXPR_H1H2:
 188                                 l1 = &(scontext->range.level[1]);
 189                                 l2 = &(tcontext->range.level[1]);
 190                                 goto mls_ops;
 191                         case CEXPR_L1H1:
 192                                 l1 = &(scontext->range.level[0]);
 193                                 l2 = &(scontext->range.level[1]);
 194                                 goto mls_ops;
 195                         case CEXPR_L2H2:
 196                                 l1 = &(tcontext->range.level[0]);
 197                                 l2 = &(tcontext->range.level[1]);
 198                                 goto mls_ops;
 199 mls_ops:
 200                         switch (e->op) {
 201                         case CEXPR_EQ:
 202                                 s[++sp] = mls_level_eq(l1, l2);
 203                                 continue;
 204                         case CEXPR_NEQ:
 205                                 s[++sp] = !mls_level_eq(l1, l2);
 206                                 continue;
 207                         case CEXPR_DOM:
 208                                 s[++sp] = mls_level_dom(l1, l2);
 209                                 continue;
 210                         case CEXPR_DOMBY:
 211                                 s[++sp] = mls_level_dom(l2, l1);
 212                                 continue;
 213                         case CEXPR_INCOMP:
 214                                 s[++sp] = mls_level_incomp(l2, l1);
 215                                 continue;
 216                         default:
 217                                 BUG();
 218                                 return 0;
 219                         }
 220                         break;
 221                         default:
 222                                 BUG();
 223                                 return 0;
 224                         }
 225
 226                         switch (e->op) {
 227                         case CEXPR_EQ:
 228                                 s[++sp] = (val1 == val2);
 229                                 break;
 230                         case CEXPR_NEQ:
 231                                 s[++sp] = (val1 != val2);
 232                                 break;
 233                         default:
 234                                 BUG();
 235                                 return 0;
 236                         }
 237                         break;
 238                 case CEXPR_NAMES:
 239                         if (sp == (CEXPR_MAXDEPTH-1))
 240                                 return 0;
 241                         c = scontext;
 242                         if (e->attr & CEXPR_TARGET)
 243                                 c = tcontext;
 244                         else if (e->attr & CEXPR_XTARGET) {
 245                                 c = xcontext;
 246                                 if (!c) {
 247                                         BUG();
 248                                         return 0;
 249                                 }
 250                         }
 251                         if (e->attr & CEXPR_USER)
 252                                 val1 = c->user;
 253                         else if (e->attr & CEXPR_ROLE)
 254                                 val1 = c->role;
 255                         else if (e->attr & CEXPR_TYPE)
 256                                 val1 = c->type;
 257                         else {
 258                                 BUG();
 259                                 return 0;
 260                         }
 261
 262                         switch (e->op) {
 263                         case CEXPR_EQ:
 264                                 s[++sp] = ebitmap_get_bit(&e->names, val1 - 1);
 265                                 break;
 266                         case CEXPR_NEQ:
 267                                 s[++sp] = !ebitmap_get_bit(&e->names, val1 - 1);
 268                                 break;
 269                         default:
 270                                 BUG();
 271                                 return 0;
 272                         }
 273                         break;
 274                 default:
 275                         BUG();
 276                         return 0;
 277                 }
 278         }
 279
 280         BUG_ON(sp != 0);
 281         return s[0];
 282 }
 283
 284 /*
 285  * Compute access vectors based on a context structure pair for
 286  * the permissions in a particular class.
 287  */
 288 static int context_struct_compute_av(struct context *scontext,
 289                                      struct context *tcontext,
 290                                      u16 tclass,
 291                                      u32 requested,
 292                                      struct av_decision *avd)
 293 {
 294         struct constraint_node *constraint;
 295         struct role_allow *ra;
 296         struct avtab_key avkey;
 297         struct avtab_node *node;
 298         struct class_datum *tclass_datum;
 299         struct ebitmap *sattr, *tattr;
 300         struct ebitmap_node *snode, *tnode;
 301         const struct selinux_class_perm *kdefs = &selinux_class_perm;
 302         unsigned int i, j;
 303
 304         /*
 305          * Remap extended Netlink classes for old policy versions.
 306          * Do this here rather than socket_type_to_security_class()
 307          * in case a newer policy version is loaded, allowing sockets
 308          * to remain in the correct class.
 309          */
 310         if (policydb_loaded_version < POLICYDB_VERSION_NLCLASS)
 311                 if (tclass >= SECCLASS_NETLINK_ROUTE_SOCKET &&
 312                     tclass <= SECCLASS_NETLINK_DNRT_SOCKET)
 313                         tclass = SECCLASS_NETLINK_SOCKET;
 314
 315         /*
 316          * Initialize the access vectors to the default values.
 317          */
 318         avd->allowed = 0;
 319         avd->decided = 0xffffffff;
 320         avd->auditallow = 0;
 321         avd->auditdeny = 0xffffffff;
 322         avd->seqno = latest_granting;
 323
 324         /*
 325          * Check for all the invalid cases.
 326          * - tclass 0
 327          * - tclass > policy and > kernel
 328          * - tclass > policy but is a userspace class
 329          * - tclass > policy but we do not allow unknowns
 330          */
 331         if (unlikely(!tclass))
 332                 goto inval_class;
 333         if (unlikely(tclass > policydb.p_classes.nprim))
 334                 if (tclass > kdefs->cts_len ||
 335                     !kdefs->class_to_string[tclass - 1] ||
 336                     !policydb.allow_unknown)
 337                         goto inval_class;
 338
 339         /*
 340          * Kernel class and we allow unknown so pad the allow decision
 341          * the pad will be all 1 for unknown classes.
 342          */
 343         if (tclass <= kdefs->cts_len && policydb.allow_unknown)
 344                 avd->allowed = policydb.undefined_perms[tclass - 1];
 345
 346         /*
 347          * Not in policy. Since decision is completed (all 1 or all 0) return.
 348          */
 349         if (unlikely(tclass > policydb.p_classes.nprim))
 350                 return 0;
 351
 352         tclass_datum = policydb.class_val_to_struct[tclass - 1];
 353
 354         /*
 355          * If a specific type enforcement rule was defined for
 356          * this permission check, then use it.
 357          */
 358         avkey.target_class = tclass;
 359         avkey.specified = AVTAB_AV;
 360         sattr = &policydb.type_attr_map[scontext->type - 1];
 361         tattr = &policydb.type_attr_map[tcontext->type - 1];
 362         ebitmap_for_each_positive_bit(sattr, snode, i) {
 363                 ebitmap_for_each_positive_bit(tattr, tnode, j) {
 364                         avkey.source_type = i + 1;
 365                         avkey.target_type = j + 1;
 366                         for (node = avtab_search_node(&policydb.te_avtab, &avkey);
 367                              node != NULL;
 368                              node = avtab_search_node_next(node, avkey.specified)) {
 369                                 if (node->key.specified == AVTAB_ALLOWED)
 370                                         avd->allowed |= node->datum.data;
 371                                 else if (node->key.specified == AVTAB_AUDITALLOW)
 372                                         avd->auditallow |= node->datum.data;
 373                                 else if (node->key.specified == AVTAB_AUDITDENY)
 374                                         avd->auditdeny &= node->datum.data;
 375                         }
 376
 377                         /* Check conditional av table for additional permissions */
 378                         cond_compute_av(&policydb.te_cond_avtab, &avkey, avd);
 379
 380                 }
 381         }
 382
 383         /*
 384          * Remove any permissions prohibited by a constraint (this includes
 385          * the MLS policy).
 386          */
 387         constraint = tclass_datum->constraints;
 388         while (constraint) {
 389                 if ((constraint->permissions & (avd->allowed)) &&
 390                     !constraint_expr_eval(scontext, tcontext, NULL,
 391                                           constraint->expr)) {
 392                         avd->allowed = (avd->allowed) & ~(constraint->permissions);
 393                 }
 394                 constraint = constraint->next;
 395         }
 396
 397         /*
 398          * If checking process transition permission and the
 399          * role is changing, then check the (current_role, new_role)
 400          * pair.
 401          */
 402         if (tclass == SECCLASS_PROCESS &&
 403             (avd->allowed & (PROCESS__TRANSITION | PROCESS__DYNTRANSITION)) &&
 404             scontext->role != tcontext->role) {
 405                 for (ra = policydb.role_allow; ra; ra = ra->next) {
 406                         if (scontext->role == ra->role &&
 407                             tcontext->role == ra->new_role)
 408                                 break;
 409                 }
 410                 if (!ra)
 411                         avd->allowed = (avd->allowed) & ~(PROCESS__TRANSITION |
 412                                                         PROCESS__DYNTRANSITION);
 413         }
 414
 415         return 0;
 416
 417 inval_class:
 418         printk(KERN_ERR "%s:  unrecognized class %d\n", __func__, tclass);
 419         return -EINVAL;
 420 }
 421
 422 /*
 423  * Given a sid find if the type has the permissive flag set
 424  */
 425 int security_permissive_sid(u32 sid)
 426 {
 427         struct context *context;
 428         u32 type;
 429         int rc;
 430
 431         POLICY_RDLOCK;
 432
 433         context = sidtab_search(&sidtab, sid);
 434         BUG_ON(!context);
 435
 436         type = context->type;
 437         /*
 438          * we are intentionally using type here, not type-1, the 0th bit may
 439          * someday indicate that we are globally setting permissive in policy.
 440          */
 441         rc = ebitmap_get_bit(&policydb.permissive_map, type);
 442
 443         POLICY_RDUNLOCK;
 444         return rc;
 445 }
 446
 447 static int security_validtrans_handle_fail(struct context *ocontext,
 448                                            struct context *ncontext,
 449                                            struct context *tcontext,
 450                                            u16 tclass)
 451 {
 452         char *o = NULL, *n = NULL, *t = NULL;
 453         u32 olen, nlen, tlen;
 454
 455         if (context_struct_to_string(ocontext, &o, &olen) < 0)
 456                 goto out;
 457         if (context_struct_to_string(ncontext, &n, &nlen) < 0)
 458                 goto out;
 459         if (context_struct_to_string(tcontext, &t, &tlen) < 0)
 460                 goto out;
 461         audit_log(current->audit_context, GFP_ATOMIC, AUDIT_SELINUX_ERR,
 462                   "security_validate_transition:  denied for"
 463                   " oldcontext=%s newcontext=%s taskcontext=%s tclass=%s",
 464                   o, n, t, policydb.p_class_val_to_name[tclass-1]);
 465 out:
 466         kfree(o);
 467         kfree(n);
 468         kfree(t);
 469
 470         if (!selinux_enforcing)
 471                 return 0;
 472         return -EPERM;
 473 }
 474
 475 int security_validate_transition(u32 oldsid, u32 newsid, u32 tasksid,
 476                                  u16 tclass)
 477 {
 478         struct context *ocontext;
 479         struct context *ncontext;
 480         struct context *tcontext;
 481         struct class_datum *tclass_datum;
 482         struct constraint_node *constraint;
 483         int rc = 0;
 484
 485         if (!ss_initialized)
 486                 return 0;
 487
 488         POLICY_RDLOCK;
 489
 490         /*
 491          * Remap extended Netlink classes for old policy versions.
 492          * Do this here rather than socket_type_to_security_class()
 493          * in case a newer policy version is loaded, allowing sockets
 494          * to remain in the correct class.
 495          */
 496         if (policydb_loaded_version < POLICYDB_VERSION_NLCLASS)
 497                 if (tclass >= SECCLASS_NETLINK_ROUTE_SOCKET &&
 498                     tclass <= SECCLASS_NETLINK_DNRT_SOCKET)
 499                         tclass = SECCLASS_NETLINK_SOCKET;
 500
 501         if (!tclass || tclass > policydb.p_classes.nprim) {
 502                 printk(KERN_ERR "security_validate_transition:  "
 503                        "unrecognized class %d\n", tclass);
 504                 rc = -EINVAL;
 505                 goto out;
 506         }
 507         tclass_datum = policydb.class_val_to_struct[tclass - 1];
 508
 509         ocontext = sidtab_search(&sidtab, oldsid);
 510         if (!ocontext) {
 511                 printk(KERN_ERR "security_validate_transition: "
 512                        " unrecognized SID %d\n", oldsid);
 513                 rc = -EINVAL;
 514                 goto out;
 515         }
 516
 517         ncontext = sidtab_search(&sidtab, newsid);
 518         if (!ncontext) {
 519                 printk(KERN_ERR "security_validate_transition: "
 520                        " unrecognized SID %d\n", newsid);
 521                 rc = -EINVAL;
 522                 goto out;
 523         }
 524
 525         tcontext = sidtab_search(&sidtab, tasksid);
 526         if (!tcontext) {
 527                 printk(KERN_ERR "security_validate_transition: "
 528                        " unrecognized SID %d\n", tasksid);
 529                 rc = -EINVAL;
 530                 goto out;
 531         }
 532
 533         constraint = tclass_datum->validatetrans;
 534         while (constraint) {
 535                 if (!constraint_expr_eval(ocontext, ncontext, tcontext,
 536                                           constraint->expr)) {
 537                         rc = security_validtrans_handle_fail(ocontext, ncontext,
 538                                                              tcontext, tclass);
 539                         goto out;
 540                 }
 541                 constraint = constraint->next;
 542         }
 543
 544 out:
 545         POLICY_RDUNLOCK;
 546         return rc;
 547 }
 548
 549 /**
 550  * security_compute_av - Compute access vector decisions.
 551  * @ssid: source security identifier
 552  * @tsid: target security identifier
 553  * @tclass: target security class
 554  * @requested: requested permissions
 555  * @avd: access vector decisions
 556  *
 557  * Compute a set of access vector decisions based on the
 558  * SID pair (@ssid, @tsid) for the permissions in @tclass.
 559  * Return -%EINVAL if any of the parameters are invalid or %0
 560  * if the access vector decisions were computed successfully.
 561  */
 562 int security_compute_av(u32 ssid,
 563                         u32 tsid,
 564                         u16 tclass,
 565                         u32 requested,
 566                         struct av_decision *avd)
 567 {
 568         struct context *scontext = NULL, *tcontext = NULL;
 569         int rc = 0;
 570
 571         if (!ss_initialized) {
 572                 avd->allowed = 0xffffffff;
 573                 avd->decided = 0xffffffff;
 574                 avd->auditallow = 0;
 575                 avd->auditdeny = 0xffffffff;
 576                 avd->seqno = latest_granting;
 577                 return 0;
 578         }
 579
 580         POLICY_RDLOCK;
 581
 582         scontext = sidtab_search(&sidtab, ssid);
 583         if (!scontext) {
 584                 printk(KERN_ERR "security_compute_av:  unrecognized SID %d\n",
 585                        ssid);
 586                 rc = -EINVAL;
 587                 goto out;
 588         }
 589         tcontext = sidtab_search(&sidtab, tsid);
 590         if (!tcontext) {
 591                 printk(KERN_ERR "security_compute_av:  unrecognized SID %d\n",
 592                        tsid);
 593                 rc = -EINVAL;
 594                 goto out;
 595         }
 596
 597         rc = context_struct_compute_av(scontext, tcontext, tclass,
 598                                        requested, avd);
 599 out:
 600         POLICY_RDUNLOCK;
 601         return rc;
 602 }
 603
 604 /*
 605  * Write the security context string representation of
 606  * the context structure `context' into a dynamically
 607  * allocated string of the correct size.  Set `*scontext'
 608  * to point to this string and set `*scontext_len' to
 609  * the length of the string.
 610  */
 611 static int context_struct_to_string(struct context *context, char **scontext, u32 *scontext_len)
 612 {
 613         char *scontextp;
 614
 615         *scontext = NULL;
 616         *scontext_len = 0;
 617
 618         /* Compute the size of the context. */
 619         *scontext_len += strlen(policydb.p_user_val_to_name[context->user - 1]) + 1;
 620         *scontext_len += strlen(policydb.p_role_val_to_name[context->role - 1]) + 1;
 621         *scontext_len += strlen(policydb.p_type_val_to_name[context->type - 1]) + 1;
 622         *scontext_len += mls_compute_context_len(context);
 623
 624         /* Allocate space for the context; caller must free this space. */
 625         scontextp = kmalloc(*scontext_len, GFP_ATOMIC);
 626         if (!scontextp)
 627                 return -ENOMEM;
 628         *scontext = scontextp;
 629
 630         /*
 631          * Copy the user name, role name and type name into the context.
 632          */
 633         sprintf(scontextp, "%s:%s:%s",
 634                 policydb.p_user_val_to_name[context->user - 1],
 635                 policydb.p_role_val_to_name[context->role - 1],
 636                 policydb.p_type_val_to_name[context->type - 1]);
 637         scontextp += strlen(policydb.p_user_val_to_name[context->user - 1]) +
 638                      1 + strlen(policydb.p_role_val_to_name[context->role - 1]) +
 639                      1 + strlen(policydb.p_type_val_to_name[context->type - 1]);
 640
 641         mls_sid_to_context(context, &scontextp);
 642
 643         *scontextp = 0;
 644
 645         return 0;
 646 }
 647
 648 #include "initial_sid_to_string.h"
 649
 650 const char *security_get_initial_sid_context(u32 sid)
 651 {
 652         if (unlikely(sid > SECINITSID_NUM))
 653                 return NULL;
 654         return initial_sid_to_string[sid];
 655 }
 656
 657 /**
 658  * security_sid_to_context - Obtain a context for a given SID.
 659  * @sid: security identifier, SID
 660  * @scontext: security context
 661  * @scontext_len: length in bytes
 662  *
 663  * Write the string representation of the context associated with @sid
 664  * into a dynamically allocated string of the correct size.  Set @scontext
 665  * to point to this string and set @scontext_len to the length of the string.
 666  */
 667 int security_sid_to_context(u32 sid, char **scontext, u32 *scontext_len)
 668 {
 669         struct context *context;
 670         int rc = 0;
 671
 672         *scontext = NULL;
 673         *scontext_len  = 0;
 674
 675         if (!ss_initialized) {
 676                 if (sid <= SECINITSID_NUM) {
 677                         char *scontextp;
 678
 679                         *scontext_len = strlen(initial_sid_to_string[sid]) + 1;
 680                         scontextp = kmalloc(*scontext_len, GFP_ATOMIC);
 681                         if (!scontextp) {
 682                                 rc = -ENOMEM;
 683                                 goto out;
 684                         }
 685                         strcpy(scontextp, initial_sid_to_string[sid]);
 686                         *scontext = scontextp;
 687                         goto out;
 688                 }
 689                 printk(KERN_ERR "security_sid_to_context:  called before initial "
 690                        "load_policy on unknown SID %d\n", sid);
 691                 rc = -EINVAL;
 692                 goto out;
 693         }
 694         POLICY_RDLOCK;
 695         context = sidtab_search(&sidtab, sid);
 696         if (!context) {
 697                 printk(KERN_ERR "security_sid_to_context:  unrecognized SID "
 698                        "%d\n", sid);
 699                 rc = -EINVAL;
 700                 goto out_unlock;
 701         }
 702         rc = context_struct_to_string(context, scontext, scontext_len);
 703 out_unlock:
 704         POLICY_RDUNLOCK;
 705 out:
 706         return rc;
 707
 708 }
 709
 710 static int security_context_to_sid_core(char *scontext, u32 scontext_len,
 711                                         u32 *sid, u32 def_sid, gfp_t gfp_flags)
 712 {
 713         char *scontext2;
 714         struct context context;
 715         struct role_datum *role;
 716         struct type_datum *typdatum;
 717         struct user_datum *usrdatum;
 718         char *scontextp, *p, oldc;
 719         int rc = 0;
 720
 721         if (!ss_initialized) {
 722                 int i;
 723
 724                 for (i = 1; i < SECINITSID_NUM; i++) {
 725                         if (!strcmp(initial_sid_to_string[i], scontext)) {
 726                                 *sid = i;
 727                                 goto out;
 728                         }
 729                 }
 730                 *sid = SECINITSID_KERNEL;
 731                 goto out;
 732         }
 733         *sid = SECSID_NULL;
 734
 735         /* Copy the string so that we can modify the copy as we parse it.
 736            The string should already by null terminated, but we append a
 737            null suffix to the copy to avoid problems with the existing
 738            attr package, which doesn't view the null terminator as part
 739            of the attribute value. */
 740         scontext2 = kmalloc(scontext_len+1, gfp_flags);
 741         if (!scontext2) {
 742                 rc = -ENOMEM;
 743                 goto out;
 744         }
 745         memcpy(scontext2, scontext, scontext_len);
 746         scontext2[scontext_len] = 0;
 747
 748         context_init(&context);
 749         *sid = SECSID_NULL;
 750
 751         POLICY_RDLOCK;
 752
 753         /* Parse the security context. */
 754
 755         rc = -EINVAL;
 756         scontextp = (char *) scontext2;
 757
 758         /* Extract the user. */
 759         p = scontextp;
 760         while (*p && *p != ':')
 761                 p++;
 762
 763         if (*p == 0)
 764                 goto out_unlock;
 765
 766         *p++ = 0;
 767
 768         usrdatum = hashtab_search(policydb.p_users.table, scontextp);
 769         if (!usrdatum)
 770                 goto out_unlock;
 771
 772         context.user = usrdatum->value;
 773
 774         /* Extract role. */
 775         scontextp = p;
 776         while (*p && *p != ':')
 777                 p++;
 778
 779         if (*p == 0)
 780                 goto out_unlock;
 781
 782         *p++ = 0;
 783
 784         role = hashtab_search(policydb.p_roles.table, scontextp);
 785         if (!role)
 786                 goto out_unlock;
 787         context.role = role->value;
 788
 789         /* Extract type. */
 790         scontextp = p;
 791         while (*p && *p != ':')
 792                 p++;
 793         oldc = *p;
 794         *p++ = 0;
 795
 796         typdatum = hashtab_search(policydb.p_types.table, scontextp);
 797         if (!typdatum)
 798                 goto out_unlock;
 799
 800         context.type = typdatum->value;
 801
 802         rc = mls_context_to_sid(oldc, &p, &context, &sidtab, def_sid);
 803         if (rc)
 804                 goto out_unlock;
 805
 806         if ((p - scontext2) < scontext_len) {
 807                 rc = -EINVAL;
 808                 goto out_unlock;
 809         }
 810
 811         /* Check the validity of the new context. */
 812         if (!policydb_context_isvalid(&policydb, &context)) {
 813                 rc = -EINVAL;
 814                 goto out_unlock;
 815         }
 816         /* Obtain the new sid. */
 817         rc = sidtab_context_to_sid(&sidtab, &context, sid);
 818 out_unlock:
 819         POLICY_RDUNLOCK;
 820         context_destroy(&context);
 821         kfree(scontext2);
 822 out:
 823         return rc;
 824 }
 825
 826 /**
 827  * security_context_to_sid - Obtain a SID for a given security context.
 828  * @scontext: security context
 829  * @scontext_len: length in bytes
 830  * @sid: security identifier, SID
 831  *
 832  * Obtains a SID associated with the security context that
 833  * has the string representation specified by @scontext.
 834  * Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient
 835  * memory is available, or 0 on success.
 836  */
 837 int security_context_to_sid(char *scontext, u32 scontext_len, u32 *sid)
 838 {
 839         return security_context_to_sid_core(scontext, scontext_len,
 840                                             sid, SECSID_NULL, GFP_KERNEL);
 841 }
 842
 843 /**
 844  * security_context_to_sid_default - Obtain a SID for a given security context,
 845  * falling back to specified default if needed.
 846  *
 847  * @scontext: security context
 848  * @scontext_len: length in bytes
 849  * @sid: security identifier, SID
 850  * @def_sid: default SID to assign on error
 851  *
 852  * Obtains a SID associated with the security context that
 853  * has the string representation specified by @scontext.
 854  * The default SID is passed to the MLS layer to be used to allow
 855  * kernel labeling of the MLS field if the MLS field is not present
 856  * (for upgrading to MLS without full relabel).
 857  * Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient
 858  * memory is available, or 0 on success.
 859  */
 860 int security_context_to_sid_default(char *scontext, u32 scontext_len, u32 *sid,
 861                                     u32 def_sid, gfp_t gfp_flags)
 862 {
 863         return security_context_to_sid_core(scontext, scontext_len,
 864                                             sid, def_sid, gfp_flags);
 865 }
 866
 867 static int compute_sid_handle_invalid_context(
 868         struct context *scontext,
 869         struct context *tcontext,
 870         u16 tclass,
 871         struct context *newcontext)
 872 {
 873         char *s = NULL, *t = NULL, *n = NULL;
 874         u32 slen, tlen, nlen;
 875
 876         if (context_struct_to_string(scontext, &s, &slen) < 0)
 877                 goto out;
 878         if (context_struct_to_string(tcontext, &t, &tlen) < 0)
 879                 goto out;
 880         if (context_struct_to_string(newcontext, &n, &nlen) < 0)
 881                 goto out;
 882         audit_log(current->audit_context, GFP_ATOMIC, AUDIT_SELINUX_ERR,
 883                   "security_compute_sid:  invalid context %s"
 884                   " for scontext=%s"
 885                   " tcontext=%s"
 886                   " tclass=%s",
 887                   n, s, t, policydb.p_class_val_to_name[tclass-1]);
 888 out:
 889         kfree(s);
 890         kfree(t);
 891         kfree(n);
 892         if (!selinux_enforcing)
 893                 return 0;
 894         return -EACCES;
 895 }
 896
 897 static int security_compute_sid(u32 ssid,
 898                                 u32 tsid,
 899                                 u16 tclass,
 900                                 u32 specified,
 901                                 u32 *out_sid)
 902 {
 903         struct context *scontext = NULL, *tcontext = NULL, newcontext;
 904         struct role_trans *roletr = NULL;
 905         struct avtab_key avkey;
 906         struct avtab_datum *avdatum;
 907         struct avtab_node *node;
 908         int rc = 0;
 909
 910         if (!ss_initialized) {
 911                 switch (tclass) {
 912                 case SECCLASS_PROCESS:
 913                         *out_sid = ssid;
 914                         break;
 915                 default:
 916                         *out_sid = tsid;
 917                         break;
 918                 }
 919                 goto out;
 920         }
 921
 922         context_init(&newcontext);
 923
 924         POLICY_RDLOCK;
 925
 926         scontext = sidtab_search(&sidtab, ssid);
 927         if (!scontext) {
 928                 printk(KERN_ERR "security_compute_sid:  unrecognized SID %d\n",
 929                        ssid);
 930                 rc = -EINVAL;
 931                 goto out_unlock;
 932         }
 933         tcontext = sidtab_search(&sidtab, tsid);
 934         if (!tcontext) {
 935                 printk(KERN_ERR "security_compute_sid:  unrecognized SID %d\n",
 936                        tsid);
 937                 rc = -EINVAL;
 938                 goto out_unlock;
 939         }
 940
 941         /* Set the user identity. */
 942         switch (specified) {
 943         case AVTAB_TRANSITION:
 944         case AVTAB_CHANGE:
 945                 /* Use the process user identity. */
 946                 newcontext.user = scontext->user;
 947                 break;
 948         case AVTAB_MEMBER:
 949                 /* Use the related object owner. */
 950                 newcontext.user = tcontext->user;
 951                 break;
 952         }
 953
 954         /* Set the role and type to default values. */
 955         switch (tclass) {
 956         case SECCLASS_PROCESS:
 957                 /* Use the current role and type of process. */
 958                 newcontext.role = scontext->role;
 959                 newcontext.type = scontext->type;
 960                 break;
 961         default:
 962                 /* Use the well-defined object role. */
 963                 newcontext.role = OBJECT_R_VAL;
 964                 /* Use the type of the related object. */
 965                 newcontext.type = tcontext->type;
 966         }
 967
 968         /* Look for a type transition/member/change rule. */
 969         avkey.source_type = scontext->type;
 970         avkey.target_type = tcontext->type;
 971         avkey.target_class = tclass;
 972         avkey.specified = specified;
 973         avdatum = avtab_search(&policydb.te_avtab, &avkey);
 974
 975         /* If no permanent rule, also check for enabled conditional rules */
 976         if (!avdatum) {
 977                 node = avtab_search_node(&policydb.te_cond_avtab, &avkey);
 978                 for (; node != NULL; node = avtab_search_node_next(node, specified)) {
 979                         if (node->key.specified & AVTAB_ENABLED) {
 980                                 avdatum = &node->datum;
 981                                 break;
 982                         }
 983                 }
 984         }
 985
 986         if (avdatum) {
 987                 /* Use the type from the type transition/member/change rule. */
 988                 newcontext.type = avdatum->data;
 989         }
 990
 991         /* Check for class-specific changes. */
 992         switch (tclass) {
 993         case SECCLASS_PROCESS:
 994                 if (specified & AVTAB_TRANSITION) {
 995                         /* Look for a role transition rule. */
 996                         for (roletr = policydb.role_tr; roletr;
 997                              roletr = roletr->next) {
 998                                 if (roletr->role == scontext->role &&
 999                                     roletr->type == tcontext->type) {
1000                                         /* Use the role transition rule. */
1001                                         newcontext.role = roletr->new_role;
1002                                         break;
1003                                 }
1004                         }
1005                 }
1006                 break;
1007         default:
1008                 break;
1009         }
1010
1011         /* Set the MLS attributes.
1012            This is done last because it may allocate memory. */
1013         rc = mls_compute_sid(scontext, tcontext, tclass, specified, &newcontext);
1014         if (rc)
1015                 goto out_unlock;
1016
1017         /* Check the validity of the context. */
1018         if (!policydb_context_isvalid(&policydb, &newcontext)) {
1019                 rc = compute_sid_handle_invalid_context(scontext,
1020                                                         tcontext,
1021                                                         tclass,
1022                                                         &newcontext);
1023                 if (rc)
1024                         goto out_unlock;
1025         }
1026         /* Obtain the sid for the context. */
1027         rc = sidtab_context_to_sid(&sidtab, &newcontext, out_sid);
1028 out_unlock:
1029         POLICY_RDUNLOCK;
1030         context_destroy(&newcontext);
1031 out:
1032         return rc;
1033 }
1034
1035 /**
1036  * security_transition_sid - Compute the SID for a new subject/object.
1037  * @ssid: source security identifier
1038  * @tsid: target security identifier
1039  * @tclass: target security class
1040  * @out_sid: security identifier for new subject/object
1041  *
1042  * Compute a SID to use for labeling a new subject or object in the
1043  * class @tclass based on a SID pair (@ssid, @tsid).
1044  * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1045  * if insufficient memory is available, or %0 if the new SID was
1046  * computed successfully.
1047  */
1048 int security_transition_sid(u32 ssid,
1049                             u32 tsid,
1050                             u16 tclass,
1051                             u32 *out_sid)
1052 {
1053         return security_compute_sid(ssid, tsid, tclass, AVTAB_TRANSITION, out_sid);
1054 }
1055
1056 /**
1057  * security_member_sid - Compute the SID for member selection.
1058  * @ssid: source security identifier
1059  * @tsid: target security identifier
1060  * @tclass: target security class
1061  * @out_sid: security identifier for selected member
1062  *
1063  * Compute a SID to use when selecting a member of a polyinstantiated
1064  * object of class @tclass based on a SID pair (@ssid, @tsid).
1065  * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1066  * if insufficient memory is available, or %0 if the SID was
1067  * computed successfully.
1068  */
1069 int security_member_sid(u32 ssid,
1070                         u32 tsid,
1071                         u16 tclass,
1072                         u32 *out_sid)
1073 {
1074         return security_compute_sid(ssid, tsid, tclass, AVTAB_MEMBER, out_sid);
1075 }
1076
1077 /**
1078  * security_change_sid - Compute the SID for object relabeling.
1079  * @ssid: source security identifier
1080  * @tsid: target security identifier
1081  * @tclass: target security class
1082  * @out_sid: security identifier for selected member
1083  *
1084  * Compute a SID to use for relabeling an object of class @tclass
1085  * based on a SID pair (@ssid, @tsid).
1086  * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1087  * if insufficient memory is available, or %0 if the SID was
1088  * computed successfully.
1089  */
1090 int security_change_sid(u32 ssid,
1091                         u32 tsid,
1092                         u16 tclass,
1093                         u32 *out_sid)
1094 {
1095         return security_compute_sid(ssid, tsid, tclass, AVTAB_CHANGE, out_sid);
1096 }
1097
1098 /*
1099  * Verify that each kernel class that is defined in the
1100  * policy is correct
1101  */
1102 static int validate_classes(struct policydb *p)
1103 {
1104         int i, j;
1105         struct class_datum *cladatum;
1106         struct perm_datum *perdatum;
1107         u32 nprim, tmp, common_pts_len, perm_val, pol_val;
1108         u16 class_val;
1109         const struct selinux_class_perm *kdefs = &selinux_class_perm;
1110         const char *def_class, *def_perm, *pol_class;
1111         struct symtab *perms;
1112
1113         if (p->allow_unknown) {
1114                 u32 num_classes = kdefs->cts_len;
1115                 p->undefined_perms = kcalloc(num_classes, sizeof(u32), GFP_KERNEL);
1116                 if (!p->undefined_perms)
1117                         return -ENOMEM;
1118         }
1119
1120         for (i = 1; i < kdefs->cts_len; i++) {
1121                 def_class = kdefs->class_to_string[i];
1122                 if (!def_class)
1123                         continue;
1124                 if (i > p->p_classes.nprim) {
1125                         printk(KERN_INFO
1126                                "SELinux:  class %s not defined in policy\n",
1127                                def_class);
1128                         if (p->reject_unknown)
1129                                 return -EINVAL;
1130                         if (p->allow_unknown)
1131                                 p->undefined_perms[i-1] = ~0U;
1132                         continue;
1133                 }
1134                 pol_class = p->p_class_val_to_name[i-1];
1135                 if (strcmp(pol_class, def_class)) {
1136                         printk(KERN_ERR
1137                                "SELinux:  class %d is incorrect, found %s but should be %s\n",
1138                                i, pol_class, def_class);
1139                         return -EINVAL;
1140                 }
1141         }
1142         for (i = 0; i < kdefs->av_pts_len; i++) {
1143                 class_val = kdefs->av_perm_to_string[i].tclass;
1144                 perm_val = kdefs->av_perm_to_string[i].value;
1145                 def_perm = kdefs->av_perm_to_string[i].name;
1146                 if (class_val > p->p_classes.nprim)
1147                         continue;
1148                 pol_class = p->p_class_val_to_name[class_val-1];
1149                 cladatum = hashtab_search(p->p_classes.table, pol_class);
1150                 BUG_ON(!cladatum);
1151                 perms = &cladatum->permissions;
1152                 nprim = 1 << (perms->nprim - 1);
1153                 if (perm_val > nprim) {
1154                         printk(KERN_INFO
1155                                "SELinux:  permission %s in class %s not defined in policy\n",
1156                                def_perm, pol_class);
1157                         if (p->reject_unknown)
1158                                 return -EINVAL;
1159                         if (p->allow_unknown)
1160                                 p->undefined_perms[class_val-1] |= perm_val;
1161                         continue;
1162                 }
1163                 perdatum = hashtab_search(perms->table, def_perm);
1164                 if (perdatum == NULL) {
1165                         printk(KERN_ERR
1166                                "SELinux:  permission %s in class %s not found in policy, bad policy\n",
1167                                def_perm, pol_class);
1168                         return -EINVAL;
1169                 }
1170                 pol_val = 1 << (perdatum->value - 1);
1171                 if (pol_val != perm_val) {
1172                         printk(KERN_ERR
1173                                "SELinux:  permission %s in class %s has incorrect value\n",
1174                                def_perm, pol_class);
1175                         return -EINVAL;
1176                 }
1177         }
1178         for (i = 0; i < kdefs->av_inherit_len; i++) {
1179                 class_val = kdefs->av_inherit[i].tclass;
1180                 if (class_val > p->p_classes.nprim)
1181                         continue;
1182                 pol_class = p->p_class_val_to_name[class_val-1];
1183                 cladatum = hashtab_search(p->p_classes.table, pol_class);
1184                 BUG_ON(!cladatum);
1185                 if (!cladatum->comdatum) {
1186                         printk(KERN_ERR
1187                                "SELinux:  class %s should have an inherits clause but does not\n",
1188                                pol_class);
1189                         return -EINVAL;
1190                 }
1191                 tmp = kdefs->av_inherit[i].common_base;
1192                 common_pts_len = 0;
1193                 while (!(tmp & 0x01)) {
1194                         common_pts_len++;
1195                         tmp >>= 1;
1196                 }
1197                 perms = &cladatum->comdatum->permissions;
1198                 for (j = 0; j < common_pts_len; j++) {
1199                         def_perm = kdefs->av_inherit[i].common_pts[j];
1200                         if (j >= perms->nprim) {
1201                                 printk(KERN_INFO
1202                                        "SELinux:  permission %s in class %s not defined in policy\n",
1203                                        def_perm, pol_class);
1204                                 if (p->reject_unknown)
1205                                         return -EINVAL;
1206                                 if (p->allow_unknown)
1207                                         p->undefined_perms[class_val-1] |= (1 << j);
1208                                 continue;
1209                         }
1210                         perdatum = hashtab_search(perms->table, def_perm);
1211                         if (perdatum == NULL) {
1212                                 printk(KERN_ERR
1213                                        "SELinux:  permission %s in class %s not found in policy, bad policy\n",
1214                                        def_perm, pol_class);
1215                                 return -EINVAL;
1216                         }
1217                         if (perdatum->value != j + 1) {
1218                                 printk(KERN_ERR
1219                                        "SELinux:  permission %s in class %s has incorrect value\n",
1220                                        def_perm, pol_class);
1221                                 return -EINVAL;
1222                         }
1223                 }
1224         }
1225         return 0;
1226 }
1227
1228 /* Clone the SID into the new SID table. */
1229 static int clone_sid(u32 sid,
1230                      struct context *context,
1231                      void *arg)
1232 {
1233         struct sidtab *s = arg;
1234
1235         return sidtab_insert(s, sid, context);
1236 }
1237
1238 static inline int convert_context_handle_invalid_context(struct context *context)
1239 {
1240         int rc = 0;
1241
1242         if (selinux_enforcing) {
1243                 rc = -EINVAL;
1244         } else {
1245                 char *s;
1246                 u32 len;
1247
1248                 context_struct_to_string(context, &s, &len);
1249                 printk(KERN_ERR "SELinux:  context %s is invalid\n", s);
1250                 kfree(s);
1251         }
1252         return rc;
1253 }
1254
1255 struct convert_context_args {
1256         struct policydb *oldp;
1257         struct policydb *newp;
1258 };
1259
1260 /*
1261  * Convert the values in the security context
1262  * structure `c' from the values specified
1263  * in the policy `p->oldp' to the values specified
1264  * in the policy `p->newp'.  Verify that the
1265  * context is valid under the new policy.
1266  */
1267 static int convert_context(u32 key,
1268                            struct context *c,
1269                            void *p)
1270 {
1271         struct convert_context_args *args;
1272         struct context oldc;
1273         struct role_datum *role;
1274         struct type_datum *typdatum;
1275         struct user_datum *usrdatum;
1276         char *s;
1277         u32 len;
1278         int rc;
1279
1280         args = p;
1281
1282         rc = context_cpy(&oldc, c);
1283         if (rc)
1284                 goto out;
1285
1286         rc = -EINVAL;
1287
1288         /* Convert the user. */
1289         usrdatum = hashtab_search(args->newp->p_users.table,
1290                                   args->oldp->p_user_val_to_name[c->user - 1]);
1291         if (!usrdatum)
1292                 goto bad;
1293         c->user = usrdatum->value;
1294
1295         /* Convert the role. */
1296         role = hashtab_search(args->newp->p_roles.table,
1297                               args->oldp->p_role_val_to_name[c->role - 1]);
1298         if (!role)
1299                 goto bad;
1300         c->role = role->value;
1301
1302         /* Convert the type. */
1303         typdatum = hashtab_search(args->newp->p_types.table,
1304                                   args->oldp->p_type_val_to_name[c->type - 1]);
1305         if (!typdatum)
1306                 goto bad;
1307         c->type = typdatum->value;
1308
1309         rc = mls_convert_context(args->oldp, args->newp, c);
1310         if (rc)
1311                 goto bad;
1312
1313         /* Check the validity of the new context. */
1314         if (!policydb_context_isvalid(args->newp, c)) {
1315                 rc = convert_context_handle_invalid_context(&oldc);
1316                 if (rc)
1317                         goto bad;
1318         }
1319
1320         context_destroy(&oldc);
1321 out:
1322         return rc;
1323 bad:
1324         context_struct_to_string(&oldc, &s, &len);
1325         context_destroy(&oldc);
1326         printk(KERN_ERR "SELinux:  invalidating context %s\n", s);
1327         kfree(s);
1328         goto out;
1329 }
1330
1331 static void security_load_policycaps(void)
1332 {
1333         selinux_policycap_netpeer = ebitmap_get_bit(&policydb.policycaps,
1334                                                   POLICYDB_CAPABILITY_NETPEER);
1335         selinux_policycap_openperm = ebitmap_get_bit(&policydb.policycaps,
1336                                                   POLICYDB_CAPABILITY_OPENPERM);
1337 }
1338
1339 extern void selinux_complete_init(void);
1340 static int security_preserve_bools(struct policydb *p);
1341
1342 /**
1343  * security_load_policy - Load a security policy configuration.
1344  * @data: binary policy data
1345  * @len: length of data in bytes
1346  *
1347  * Load a new set of security policy configuration data,
1348  * validate it and convert the SID table as necessary.
1349  * This function will flush the access vector cache after
1350  * loading the new policy.
1351  */
1352 int security_load_policy(void *data, size_t len)
1353 {
1354         struct policydb oldpolicydb, newpolicydb;
1355         struct sidtab oldsidtab, newsidtab;
1356         struct convert_context_args args;
1357         u32 seqno;
1358         int rc = 0;
1359         struct policy_file file = { data, len }, *fp = &file;
1360
1361         LOAD_LOCK;
1362
1363         if (!ss_initialized) {
1364                 avtab_cache_init();
1365                 if (policydb_read(&policydb, fp)) {
1366                         LOAD_UNLOCK;
1367                         avtab_cache_destroy();
1368                         return -EINVAL;
1369                 }
1370                 if (policydb_load_isids(&policydb, &sidtab)) {
1371                         LOAD_UNLOCK;
1372                         policydb_destroy(&policydb);
1373                         avtab_cache_destroy();
1374                         return -EINVAL;
1375                 }
1376                 /* Verify that the kernel defined classes are correct. */
1377                 if (validate_classes(&policydb)) {
1378                         printk(KERN_ERR
1379                                "SELinux:  the definition of a class is incorrect\n");
1380                         LOAD_UNLOCK;
1381                         sidtab_destroy(&sidtab);
1382                         policydb_destroy(&policydb);
1383                         avtab_cache_destroy();
1384                         return -EINVAL;
1385                 }
1386                 security_load_policycaps();
1387                 policydb_loaded_version = policydb.policyvers;
1388                 ss_initialized = 1;
1389                 seqno = ++latest_granting;
1390                 LOAD_UNLOCK;
1391                 selinux_complete_init();
1392                 avc_ss_reset(seqno);
1393                 selnl_notify_policyload(seqno);
1394                 selinux_netlbl_cache_invalidate();
1395                 selinux_xfrm_notify_policyload();
1396                 return 0;
1397         }
1398
1399 #if 0
1400         sidtab_hash_eval(&sidtab, "sids");
1401 #endif
1402
1403         if (policydb_read(&newpolicydb, fp)) {
1404                 LOAD_UNLOCK;
1405                 return -EINVAL;
1406         }
1407
1408         sidtab_init(&newsidtab);
1409
1410         /* Verify that the kernel defined classes are correct. */
1411         if (validate_classes(&newpolicydb)) {
1412                 printk(KERN_ERR
1413                        "SELinux:  the definition of a class is incorrect\n");
1414                 rc = -EINVAL;
1415                 goto err;
1416         }
1417
1418         rc = security_preserve_bools(&newpolicydb);
1419         if (rc) {
1420                 printk(KERN_ERR "SELinux:  unable to preserve booleans\n");
1421                 goto err;
1422         }
1423
1424         /* Clone the SID table. */
1425         sidtab_shutdown(&sidtab);
1426         if (sidtab_map(&sidtab, clone_sid, &newsidtab)) {
1427                 rc = -ENOMEM;
1428                 goto err;
1429         }
1430
1431         /* Convert the internal representations of contexts
1432            in the new SID table and remove invalid SIDs. */
1433         args.oldp = &policydb;
1434         args.newp = &newpolicydb;
1435         sidtab_map_remove_on_error(&newsidtab, convert_context, &args);
1436
1437         /* Save the old policydb and SID table to free later. */
1438         memcpy(&oldpolicydb, &policydb, sizeof policydb);
1439         sidtab_set(&oldsidtab, &sidtab);
1440
1441         /* Install the new policydb and SID table. */
1442         POLICY_WRLOCK;
1443         memcpy(&policydb, &newpolicydb, sizeof policydb);
1444         sidtab_set(&sidtab, &newsidtab);
1445         security_load_policycaps();
1446         seqno = ++latest_granting;
1447         policydb_loaded_version = policydb.policyvers;
1448         POLICY_WRUNLOCK;
1449         LOAD_UNLOCK;
1450
1451         /* Free the old policydb and SID table. */
1452         policydb_destroy(&oldpolicydb);
1453         sidtab_destroy(&oldsidtab);
1454
1455         avc_ss_reset(seqno);
1456         selnl_notify_policyload(seqno);
1457         selinux_netlbl_cache_invalidate();
1458         selinux_xfrm_notify_policyload();
1459
1460         return 0;
1461
1462 err:
1463         LOAD_UNLOCK;
1464         sidtab_destroy(&newsidtab);
1465         policydb_destroy(&newpolicydb);
1466         return rc;
1467
1468 }
1469
1470 /**
1471  * security_port_sid - Obtain the SID for a port.
1472  * @protocol: protocol number
1473  * @port: port number
1474  * @out_sid: security identifier
1475  */
1476 int security_port_sid(u8 protocol, u16 port, u32 *out_sid)
1477 {
1478         struct ocontext *c;
1479         int rc = 0;
1480
1481         POLICY_RDLOCK;
1482
1483         c = policydb.ocontexts[OCON_PORT];
1484         while (c) {
1485                 if (c->u.port.protocol == protocol &&
1486                     c->u.port.low_port <= port &&
1487                     c->u.port.high_port >= port)
1488                         break;
1489                 c = c->next;
1490         }
1491
1492         if (c) {
1493                 if (!c->sid[0]) {
1494                         rc = sidtab_context_to_sid(&sidtab,
1495                                                    &c->context[0],
1496                                                    &c->sid[0]);
1497                         if (rc)
1498                                 goto out;
1499                 }
1500                 *out_sid = c->sid[0];
1501         } else {
1502                 *out_sid = SECINITSID_PORT;
1503         }
1504
1505 out:
1506         POLICY_RDUNLOCK;
1507         return rc;
1508 }
1509
1510 /**
1511  * security_netif_sid - Obtain the SID for a network interface.
1512  * @name: interface name
1513  * @if_sid: interface SID
1514  */
1515 int security_netif_sid(char *name, u32 *if_sid)
1516 {
1517         int rc = 0;
1518         struct ocontext *c;
1519
1520         POLICY_RDLOCK;
1521
1522         c = policydb.ocontexts[OCON_NETIF];
1523         while (c) {
1524                 if (strcmp(name, c->u.name) == 0)
1525                         break;
1526                 c = c->next;
1527         }
1528
1529         if (c) {
1530                 if (!c->sid[0] || !c->sid[1]) {
1531                         rc = sidtab_context_to_sid(&sidtab,
1532                                                   &c->context[0],
1533                                                   &c->sid[0]);
1534                         if (rc)
1535                                 goto out;
1536                         rc = sidtab_context_to_sid(&sidtab,
1537                                                    &c->context[1],
1538                                                    &c->sid[1]);
1539                         if (rc)
1540                                 goto out;
1541                 }
1542                 *if_sid = c->sid[0];
1543         } else
1544                 *if_sid = SECINITSID_NETIF;
1545
1546 out:
1547         POLICY_RDUNLOCK;
1548         return rc;
1549 }
1550
1551 static int match_ipv6_addrmask(u32 *input, u32 *addr, u32 *mask)
1552 {
1553         int i, fail = 0;
1554
1555         for (i = 0; i < 4; i++)
1556                 if (addr[i] != (input[i] & mask[i])) {
1557                         fail = 1;
1558                         break;
1559                 }
1560
1561         return !fail;
1562 }
1563
1564 /**
1565  * security_node_sid - Obtain the SID for a node (host).
1566  * @domain: communication domain aka address family
1567  * @addrp: address
1568  * @addrlen: address length in bytes
1569  * @out_sid: security identifier
1570  */
1571 int security_node_sid(u16 domain,
1572                       void *addrp,
1573                       u32 addrlen,
1574                       u32 *out_sid)
1575 {
1576         int rc = 0;
1577         struct ocontext *c;
1578
1579         POLICY_RDLOCK;
1580
1581         switch (domain) {
1582         case AF_INET: {
1583                 u32 addr;
1584
1585                 if (addrlen != sizeof(u32)) {
1586                         rc = -EINVAL;
1587                         goto out;
1588                 }
1589
1590                 addr = *((u32 *)addrp);
1591
1592                 c = policydb.ocontexts[OCON_NODE];
1593                 while (c) {
1594                         if (c->u.node.addr == (addr & c->u.node.mask))
1595                                 break;
1596                         c = c->next;
1597                 }
1598                 break;
1599         }
1600
1601         case AF_INET6:
1602                 if (addrlen != sizeof(u64) * 2) {
1603                         rc = -EINVAL;
1604                         goto out;
1605                 }
1606                 c = policydb.ocontexts[OCON_NODE6];
1607                 while (c) {
1608                         if (match_ipv6_addrmask(addrp, c->u.node6.addr,
1609                                                 c->u.node6.mask))
1610                                 break;
1611                         c = c->next;
1612                 }
1613                 break;
1614
1615         default:
1616                 *out_sid = SECINITSID_NODE;
1617                 goto out;
1618         }
1619
1620         if (c) {
1621                 if (!c->sid[0]) {
1622                         rc = sidtab_context_to_sid(&sidtab,
1623                                                    &c->context[0],
1624                                                    &c->sid[0]);
1625                         if (rc)
1626                                 goto out;
1627                 }
1628                 *out_sid = c->sid[0];
1629         } else {
1630                 *out_sid = SECINITSID_NODE;
1631         }
1632
1633 out:
1634         POLICY_RDUNLOCK;
1635         return rc;
1636 }
1637
1638 #define SIDS_NEL 25
1639
1640 /**
1641  * security_get_user_sids - Obtain reachable SIDs for a user.
1642  * @fromsid: starting SID
1643  * @username: username
1644  * @sids: array of reachable SIDs for user
1645  * @nel: number of elements in @sids
1646  *
1647  * Generate the set of SIDs for legal security contexts
1648  * for a given user that can be reached by @fromsid.
1649  * Set *@sids to point to a dynamically allocated
1650  * array containing the set of SIDs.  Set *@nel to the
1651  * number of elements in the array.
1652  */
1653
1654 int security_get_user_sids(u32 fromsid,
1655                            char *username,
1656                            u32 **sids,
1657                            u32 *nel)
1658 {
1659         struct context *fromcon, usercon;
1660         u32 *mysids = NULL, *mysids2, sid;
1661         u32 mynel = 0, maxnel = SIDS_NEL;
1662         struct user_datum *user;
1663         struct role_datum *role;
1664         struct ebitmap_node *rnode, *tnode;
1665         int rc = 0, i, j;
1666
1667         *sids = NULL;
1668         *nel = 0;
1669
1670         if (!ss_initialized)
1671                 goto out;
1672
1673         POLICY_RDLOCK;
1674
1675         fromcon = sidtab_search(&sidtab, fromsid);
1676         if (!fromcon) {
1677                 rc = -EINVAL;
1678                 goto out_unlock;
1679         }
1680
1681         user = hashtab_search(policydb.p_users.table, username);
1682         if (!user) {
1683                 rc = -EINVAL;
1684                 goto out_unlock;
1685         }
1686         usercon.user = user->value;
1687
1688         mysids = kcalloc(maxnel, sizeof(*mysids), GFP_ATOMIC);
1689         if (!mysids) {
1690                 rc = -ENOMEM;
1691                 goto out_unlock;
1692         }
1693
1694         ebitmap_for_each_positive_bit(&user->roles, rnode, i) {
1695                 role = policydb.role_val_to_struct[i];
1696                 usercon.role = i+1;
1697                 ebitmap_for_each_positive_bit(&role->types, tnode, j) {
1698                         usercon.type = j+1;
1699
1700                         if (mls_setup_user_range(fromcon, user, &usercon))
1701                                 continue;
1702
1703                         rc = sidtab_context_to_sid(&sidtab, &usercon, &sid);
1704                         if (rc)
1705                                 goto out_unlock;
1706                         if (mynel < maxnel) {
1707                                 mysids[mynel++] = sid;
1708                         } else {
1709                                 maxnel += SIDS_NEL;
1710                                 mysids2 = kcalloc(maxnel, sizeof(*mysids2), GFP_ATOMIC);
1711                                 if (!mysids2) {
1712                                         rc = -ENOMEM;
1713                                         goto out_unlock;
1714                                 }
1715                                 memcpy(mysids2, mysids, mynel * sizeof(*mysids2));
1716                                 kfree(mysids);
1717                                 mysids = mysids2;
1718                                 mysids[mynel++] = sid;
1719                         }
1720                 }
1721         }
1722
1723 out_unlock:
1724         POLICY_RDUNLOCK;
1725         if (rc || !mynel) {
1726                 kfree(mysids);
1727                 goto out;
1728         }
1729
1730         mysids2 = kcalloc(mynel, sizeof(*mysids2), GFP_KERNEL);
1731         if (!mysids2) {
1732                 rc = -ENOMEM;
1733                 kfree(mysids);
1734                 goto out;
1735         }
1736         for (i = 0, j = 0; i < mynel; i++) {
1737                 rc = avc_has_perm_noaudit(fromsid, mysids[i],
1738                                           SECCLASS_PROCESS,
1739                                           PROCESS__TRANSITION, AVC_STRICT,
1740                                           NULL);
1741                 if (!rc)
1742                         mysids2[j++] = mysids[i];
1743                 cond_resched();
1744         }
1745         rc = 0;
1746         kfree(mysids);
1747         *sids = mysids2;
1748         *nel = j;
1749 out:
1750         return rc;
1751 }
1752
1753 /**
1754  * security_genfs_sid - Obtain a SID for a file in a filesystem
1755  * @fstype: filesystem type
1756  * @path: path from root of mount
1757  * @sclass: file security class
1758  * @sid: SID for path
1759  *
1760  * Obtain a SID to use for a file in a filesystem that
1761  * cannot support xattr or use a fixed labeling behavior like
1762  * transition SIDs or task SIDs.
1763  */
1764 int security_genfs_sid(const char *fstype,
1765                        char *path,
1766                        u16 sclass,
1767                        u32 *sid)
1768 {
1769         int len;
1770         struct genfs *genfs;
1771         struct ocontext *c;
1772         int rc = 0, cmp = 0;
1773
1774         while (path[0] == '/' && path[1] == '/')
1775                 path++;
1776
1777         POLICY_RDLOCK;
1778
1779         for (genfs = policydb.genfs; genfs; genfs = genfs->next) {
1780                 cmp = strcmp(fstype, genfs->fstype);
1781                 if (cmp <= 0)
1782                         break;
1783         }
1784
1785         if (!genfs || cmp) {
1786                 *sid = SECINITSID_UNLABELED;
1787                 rc = -ENOENT;
1788                 goto out;
1789         }
1790
1791         for (c = genfs->head; c; c = c->next) {
1792                 len = strlen(c->u.name);
1793                 if ((!c->v.sclass || sclass == c->v.sclass) &&
1794                     (strncmp(c->u.name, path, len) == 0))
1795                         break;
1796         }
1797
1798         if (!c) {
1799                 *sid = SECINITSID_UNLABELED;
1800                 rc = -ENOENT;
1801                 goto out;
1802         }
1803
1804         if (!c->sid[0]) {
1805                 rc = sidtab_context_to_sid(&sidtab,
1806                                            &c->context[0],
1807                                            &c->sid[0]);
1808                 if (rc)
1809                         goto out;
1810         }
1811
1812         *sid = c->sid[0];
1813 out:
1814         POLICY_RDUNLOCK;
1815         return rc;
1816 }
1817
1818 /**
1819  * security_fs_use - Determine how to handle labeling for a filesystem.
1820  * @fstype: filesystem type
1821  * @behavior: labeling behavior
1822  * @sid: SID for filesystem (superblock)
1823  */
1824 int security_fs_use(
1825         const char *fstype,
1826         unsigned int *behavior,
1827         u32 *sid)
1828 {
1829         int rc = 0;
1830         struct ocontext *c;
1831
1832         POLICY_RDLOCK;
1833
1834         c = policydb.ocontexts[OCON_FSUSE];
1835         while (c) {
1836                 if (strcmp(fstype, c->u.name) == 0)
1837                         break;
1838                 c = c->next;
1839         }
1840
1841         if (c) {
1842                 *behavior = c->v.behavior;
1843                 if (!c->sid[0]) {
1844                         rc = sidtab_context_to_sid(&sidtab,
1845                                                    &c->context[0],
1846                                                    &c->sid[0]);
1847                         if (rc)
1848                                 goto out;
1849                 }
1850                 *sid = c->sid[0];
1851         } else {
1852                 rc = security_genfs_sid(fstype, "/", SECCLASS_DIR, sid);
1853                 if (rc) {
1854                         *behavior = SECURITY_FS_USE_NONE;
1855                         rc = 0;
1856                 } else {
1857                         *behavior = SECURITY_FS_USE_GENFS;
1858                 }
1859         }
1860
1861 out:
1862         POLICY_RDUNLOCK;
1863         return rc;
1864 }
1865
1866 int security_get_bools(int *len, char ***names, int **values)
1867 {
1868         int i, rc = -ENOMEM;
1869
1870         POLICY_RDLOCK;
1871         *names = NULL;
1872         *values = NULL;
1873
1874         *len = policydb.p_bools.nprim;
1875         if (!*len) {
1876                 rc = 0;
1877                 goto out;
1878         }
1879
1880        *names = kcalloc(*len, sizeof(char *), GFP_ATOMIC);
1881         if (!*names)
1882                 goto err;
1883
1884        *values = kcalloc(*len, sizeof(int), GFP_ATOMIC);
1885         if (!*values)
1886                 goto err;
1887
1888         for (i = 0; i < *len; i++) {
1889                 size_t name_len;
1890                 (*values)[i] = policydb.bool_val_to_struct[i]->state;
1891                 name_len = strlen(policydb.p_bool_val_to_name[i]) + 1;
1892                (*names)[i] = kmalloc(sizeof(char) * name_len, GFP_ATOMIC);
1893                 if (!(*names)[i])
1894                         goto err;
1895                 strncpy((*names)[i], policydb.p_bool_val_to_name[i], name_len);
1896                 (*names)[i][name_len - 1] = 0;
1897         }
1898         rc = 0;
1899 out:
1900         POLICY_RDUNLOCK;
1901         return rc;
1902 err:
1903         if (*names) {
1904                 for (i = 0; i < *len; i++)
1905                         kfree((*names)[i]);
1906         }
1907         kfree(*values);
1908         goto out;
1909 }
1910
1911
1912 int security_set_bools(int len, int *values)
1913 {
1914         int i, rc = 0;
1915         int lenp, seqno = 0;
1916         struct cond_node *cur;
1917
1918         POLICY_WRLOCK;
1919
1920         lenp = policydb.p_bools.nprim;
1921         if (len != lenp) {
1922                 rc = -EFAULT;
1923                 goto out;
1924         }
1925
1926         for (i = 0; i < len; i++) {
1927                 if (!!values[i] != policydb.bool_val_to_struct[i]->state) {
1928                         audit_log(current->audit_context, GFP_ATOMIC,
1929                                 AUDIT_MAC_CONFIG_CHANGE,
1930                                 "bool=%s val=%d old_val=%d auid=%u ses=%u",
1931                                 policydb.p_bool_val_to_name[i],
1932                                 !!values[i],
1933                                 policydb.bool_val_to_struct[i]->state,
1934                                 audit_get_loginuid(current),
1935                                 audit_get_sessionid(current));
1936                 }
1937                 if (values[i])
1938                         policydb.bool_val_to_struct[i]->state = 1;
1939                 else
1940                         policydb.bool_val_to_struct[i]->state = 0;
1941         }
1942
1943         for (cur = policydb.cond_list; cur != NULL; cur = cur->next) {
1944                 rc = evaluate_cond_node(&policydb, cur);
1945                 if (rc)
1946                         goto out;
1947         }
1948
1949         seqno = ++latest_granting;
1950
1951 out:
1952         POLICY_WRUNLOCK;
1953         if (!rc) {
1954                 avc_ss_reset(seqno);
1955                 selnl_notify_policyload(seqno);
1956                 selinux_xfrm_notify_policyload();
1957         }
1958         return rc;
1959 }
1960
1961 int security_get_bool_value(int bool)
1962 {
1963         int rc = 0;
1964         int len;
1965
1966         POLICY_RDLOCK;
1967
1968         len = policydb.p_bools.nprim;
1969         if (bool >= len) {
1970                 rc = -EFAULT;
1971                 goto out;
1972         }
1973
1974         rc = policydb.bool_val_to_struct[bool]->state;
1975 out:
1976         POLICY_RDUNLOCK;
1977         return rc;
1978 }
1979
1980 static int security_preserve_bools(struct policydb *p)
1981 {
1982         int rc, nbools = 0, *bvalues = NULL, i;
1983         char **bnames = NULL;
1984         struct cond_bool_datum *booldatum;
1985         struct cond_node *cur;
1986
1987         rc = security_get_bools(&nbools, &bnames, &bvalues);
1988         if (rc)
1989                 goto out;
1990         for (i = 0; i < nbools; i++) {
1991                 booldatum = hashtab_search(p->p_bools.table, bnames[i]);
1992                 if (booldatum)
1993                         booldatum->state = bvalues[i];
1994         }
1995         for (cur = p->cond_list; cur != NULL; cur = cur->next) {
1996                 rc = evaluate_cond_node(p, cur);
1997                 if (rc)
1998                         goto out;
1999         }
2000
2001 out:
2002         if (bnames) {
2003                 for (i = 0; i < nbools; i++)
2004                         kfree(bnames[i]);
2005         }
2006         kfree(bnames);
2007         kfree(bvalues);
2008         return rc;
2009 }
2010
2011 /*
2012  * security_sid_mls_copy() - computes a new sid based on the given
2013  * sid and the mls portion of mls_sid.
2014  */
2015 int security_sid_mls_copy(u32 sid, u32 mls_sid, u32 *new_sid)
2016 {
2017         struct context *context1;
2018         struct context *context2;
2019         struct context newcon;
2020         char *s;
2021         u32 len;
2022         int rc = 0;
2023
2024         if (!ss_initialized || !selinux_mls_enabled) {
2025                 *new_sid = sid;
2026                 goto out;
2027         }
2028
2029         context_init(&newcon);
2030
2031         POLICY_RDLOCK;
2032         context1 = sidtab_search(&sidtab, sid);
2033         if (!context1) {
2034                 printk(KERN_ERR "security_sid_mls_copy:  unrecognized SID "
2035                        "%d\n", sid);
2036                 rc = -EINVAL;
2037                 goto out_unlock;
2038         }
2039
2040         context2 = sidtab_search(&sidtab, mls_sid);
2041         if (!context2) {
2042                 printk(KERN_ERR "security_sid_mls_copy:  unrecognized SID "
2043                        "%d\n", mls_sid);
2044                 rc = -EINVAL;
2045                 goto out_unlock;
2046         }
2047
2048         newcon.user = context1->user;
2049         newcon.role = context1->role;
2050         newcon.type = context1->type;
2051         rc = mls_context_cpy(&newcon, context2);
2052         if (rc)
2053                 goto out_unlock;
2054
2055         /* Check the validity of the new context. */
2056         if (!policydb_context_isvalid(&policydb, &newcon)) {
2057                 rc = convert_context_handle_invalid_context(&newcon);
2058                 if (rc)
2059                         goto bad;
2060         }
2061
2062         rc = sidtab_context_to_sid(&sidtab, &newcon, new_sid);
2063         goto out_unlock;
2064
2065 bad:
2066         if (!context_struct_to_string(&newcon, &s, &len)) {
2067                 audit_log(current->audit_context, GFP_ATOMIC, AUDIT_SELINUX_ERR,
2068                           "security_sid_mls_copy: invalid context %s", s);
2069                 kfree(s);
2070         }
2071
2072 out_unlock:
2073         POLICY_RDUNLOCK;
2074         context_destroy(&newcon);
2075 out:
2076         return rc;
2077 }
2078
2079 /**
2080  * security_net_peersid_resolve - Compare and resolve two network peer SIDs
2081  * @nlbl_sid: NetLabel SID
2082  * @nlbl_type: NetLabel labeling protocol type
2083  * @xfrm_sid: XFRM SID
2084  *
2085  * Description:
2086  * Compare the @nlbl_sid and @xfrm_sid values and if the two SIDs can be
2087  * resolved into a single SID it is returned via @peer_sid and the function
2088  * returns zero.  Otherwise @peer_sid is set to SECSID_NULL and the function
2089  * returns a negative value.  A table summarizing the behavior is below:
2090  *
2091  *                                 | function return |      @sid
2092  *   ------------------------------+-----------------+-----------------
2093  *   no peer labels                |        0        |    SECSID_NULL
2094  *   single peer label             |        0        |    <peer_label>
2095  *   multiple, consistent labels   |        0        |    <peer_label>
2096  *   multiple, inconsistent labels |    -<errno>     |    SECSID_NULL
2097  *
2098  */
2099 int security_net_peersid_resolve(u32 nlbl_sid, u32 nlbl_type,
2100                                  u32 xfrm_sid,
2101                                  u32 *peer_sid)
2102 {
2103         int rc;
2104         struct context *nlbl_ctx;
2105         struct context *xfrm_ctx;
2106
2107         /* handle the common (which also happens to be the set of easy) cases
2108          * right away, these two if statements catch everything involving a
2109          * single or absent peer SID/label */
2110         if (xfrm_sid == SECSID_NULL) {
2111                 *peer_sid = nlbl_sid;
2112                 return 0;
2113         }
2114         /* NOTE: an nlbl_type == NETLBL_NLTYPE_UNLABELED is a "fallback" label
2115          * and is treated as if nlbl_sid == SECSID_NULL when a XFRM SID/label
2116          * is present */
2117         if (nlbl_sid == SECSID_NULL || nlbl_type == NETLBL_NLTYPE_UNLABELED) {
2118                 *peer_sid = xfrm_sid;
2119                 return 0;
2120         }
2121
2122         /* we don't need to check ss_initialized here since the only way both
2123          * nlbl_sid and xfrm_sid are not equal to SECSID_NULL would be if the
2124          * security server was initialized and ss_initialized was true */
2125         if (!selinux_mls_enabled) {
2126                 *peer_sid = SECSID_NULL;
2127                 return 0;
2128         }
2129
2130         POLICY_RDLOCK;
2131
2132         nlbl_ctx = sidtab_search(&sidtab, nlbl_sid);
2133         if (!nlbl_ctx) {
2134                 printk(KERN_ERR
2135                        "security_sid_mls_cmp:  unrecognized SID %d\n",
2136                        nlbl_sid);
2137                 rc = -EINVAL;
2138                 goto out_slowpath;
2139         }
2140         xfrm_ctx = sidtab_search(&sidtab, xfrm_sid);
2141         if (!xfrm_ctx) {
2142                 printk(KERN_ERR
2143                        "security_sid_mls_cmp:  unrecognized SID %d\n",
2144                        xfrm_sid);
2145                 rc = -EINVAL;
2146                 goto out_slowpath;
2147         }
2148         rc = (mls_context_cmp(nlbl_ctx, xfrm_ctx) ? 0 : -EACCES);
2149
2150 out_slowpath:
2151         POLICY_RDUNLOCK;
2152         if (rc == 0)
2153                 /* at present NetLabel SIDs/labels really only carry MLS
2154                  * information so if the MLS portion of the NetLabel SID
2155                  * matches the MLS portion of the labeled XFRM SID/label
2156                  * then pass along the XFRM SID as it is the most
2157                  * expressive */
2158                 *peer_sid = xfrm_sid;
2159         else
2160                 *peer_sid = SECSID_NULL;
2161         return rc;
2162 }
2163
2164 static int get_classes_callback(void *k, void *d, void *args)
2165 {
2166         struct class_datum *datum = d;
2167         char *name = k, **classes = args;
2168         int value = datum->value - 1;
2169
2170         classes[value] = kstrdup(name, GFP_ATOMIC);
2171         if (!classes[value])
2172                 return -ENOMEM;
2173
2174         return 0;
2175 }
2176
2177 int security_get_classes(char ***classes, int *nclasses)
2178 {
2179         int rc = -ENOMEM;
2180
2181         POLICY_RDLOCK;
2182
2183         *nclasses = policydb.p_classes.nprim;
2184         *classes = kcalloc(*nclasses, sizeof(*classes), GFP_ATOMIC);
2185         if (!*classes)
2186                 goto out;
2187
2188         rc = hashtab_map(policydb.p_classes.table, get_classes_callback,
2189                         *classes);
2190         if (rc < 0) {
2191                 int i;
2192                 for (i = 0; i < *nclasses; i++)
2193                         kfree((*classes)[i]);
2194                 kfree(*classes);
2195         }
2196
2197 out:
2198         POLICY_RDUNLOCK;
2199         return rc;
2200 }
2201
2202 static int get_permissions_callback(void *k, void *d, void *args)
2203 {
2204         struct perm_datum *datum = d;
2205         char *name = k, **perms = args;
2206         int value = datum->value - 1;
2207
2208         perms[value] = kstrdup(name, GFP_ATOMIC);
2209         if (!perms[value])
2210                 return -ENOMEM;
2211
2212         return 0;
2213 }
2214
2215 int security_get_permissions(char *class, char ***perms, int *nperms)
2216 {
2217         int rc = -ENOMEM, i;
2218         struct class_datum *match;
2219
2220         POLICY_RDLOCK;
2221
2222         match = hashtab_search(policydb.p_classes.table, class);
2223         if (!match) {
2224                 printk(KERN_ERR "%s:  unrecognized class %s\n",
2225                         __func__, class);
2226                 rc = -EINVAL;
2227                 goto out;
2228         }
2229
2230         *nperms = match->permissions.nprim;
2231         *perms = kcalloc(*nperms, sizeof(*perms), GFP_ATOMIC);
2232         if (!*perms)
2233                 goto out;
2234
2235         if (match->comdatum) {
2236                 rc = hashtab_map(match->comdatum->permissions.table,
2237                                 get_permissions_callback, *perms);
2238                 if (rc < 0)
2239                         goto err;
2240         }
2241
2242         rc = hashtab_map(match->permissions.table, get_permissions_callback,
2243                         *perms);
2244         if (rc < 0)
2245                 goto err;
2246
2247 out:
2248         POLICY_RDUNLOCK;
2249         return rc;
2250
2251 err:
2252         POLICY_RDUNLOCK;
2253         for (i = 0; i < *nperms; i++)
2254                 kfree((*perms)[i]);
2255         kfree(*perms);
2256         return rc;
2257 }
2258
2259 int security_get_reject_unknown(void)
2260 {
2261         return policydb.reject_unknown;
2262 }
2263
2264 int security_get_allow_unknown(void)
2265 {
2266         return policydb.allow_unknown;
2267 }
2268
2269 /**
2270  * security_policycap_supported - Check for a specific policy capability
2271  * @req_cap: capability
2272  *
2273  * Description:
2274  * This function queries the currently loaded policy to see if it supports the
2275  * capability specified by @req_cap.  Returns true (1) if the capability is
2276  * supported, false (0) if it isn't supported.
2277  *
2278  */
2279 int security_policycap_supported(unsigned int req_cap)
2280 {
2281         int rc;
2282
2283         POLICY_RDLOCK;
2284         rc = ebitmap_get_bit(&policydb.policycaps, req_cap);
2285         POLICY_RDUNLOCK;
2286
2287         return rc;
2288 }
2289
2290 struct selinux_audit_rule {
2291         u32 au_seqno;
2292         struct context au_ctxt;
2293 };
2294
2295 void selinux_audit_rule_free(void *vrule)
2296 {
2297         struct selinux_audit_rule *rule = vrule;
2298
2299         if (rule) {
2300                 context_destroy(&rule->au_ctxt);
2301                 kfree(rule);
2302         }
2303 }
2304
2305 int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
2306 {
2307         struct selinux_audit_rule *tmprule;
2308         struct role_datum *roledatum;
2309         struct type_datum *typedatum;
2310         struct user_datum *userdatum;
2311         struct selinux_audit_rule **rule = (struct selinux_audit_rule **)vrule;
2312         int rc = 0;
2313
2314         *rule = NULL;
2315
2316         if (!ss_initialized)
2317                 return -EOPNOTSUPP;
2318
2319         switch (field) {
2320         case AUDIT_SUBJ_USER:
2321         case AUDIT_SUBJ_ROLE:
2322         case AUDIT_SUBJ_TYPE:
2323         case AUDIT_OBJ_USER:
2324         case AUDIT_OBJ_ROLE:
2325         case AUDIT_OBJ_TYPE:
2326                 /* only 'equals' and 'not equals' fit user, role, and type */
2327                 if (op != AUDIT_EQUAL && op != AUDIT_NOT_EQUAL)
2328                         return -EINVAL;
2329                 break;
2330         case AUDIT_SUBJ_SEN:
2331         case AUDIT_SUBJ_CLR:
2332         case AUDIT_OBJ_LEV_LOW:
2333         case AUDIT_OBJ_LEV_HIGH:
2334                 /* we do not allow a range, indicated by the presense of '-' */
2335                 if (strchr(rulestr, '-'))
2336                         return -EINVAL;
2337                 break;
2338         default:
2339                 /* only the above fields are valid */
2340                 return -EINVAL;
2341         }
2342
2343         tmprule = kzalloc(sizeof(struct selinux_audit_rule), GFP_KERNEL);
2344         if (!tmprule)
2345                 return -ENOMEM;
2346
2347         context_init(&tmprule->au_ctxt);
2348
2349         POLICY_RDLOCK;
2350
2351         tmprule->au_seqno = latest_granting;
2352
2353         switch (field) {
2354         case AUDIT_SUBJ_USER:
2355         case AUDIT_OBJ_USER:
2356                 userdatum = hashtab_search(policydb.p_users.table, rulestr);
2357                 if (!userdatum)
2358                         rc = -EINVAL;
2359                 else
2360                         tmprule->au_ctxt.user = userdatum->value;
2361                 break;
2362         case AUDIT_SUBJ_ROLE:
2363         case AUDIT_OBJ_ROLE:
2364                 roledatum = hashtab_search(policydb.p_roles.table, rulestr);
2365                 if (!roledatum)
2366                         rc = -EINVAL;
2367                 else
2368                         tmprule->au_ctxt.role = roledatum->value;
2369                 break;
2370         case AUDIT_SUBJ_TYPE:
2371         case AUDIT_OBJ_TYPE:
2372                 typedatum = hashtab_search(policydb.p_types.table, rulestr);
2373                 if (!typedatum)
2374                         rc = -EINVAL;
2375                 else
2376                         tmprule->au_ctxt.type = typedatum->value;
2377                 break;
2378         case AUDIT_SUBJ_SEN:
2379         case AUDIT_SUBJ_CLR:
2380         case AUDIT_OBJ_LEV_LOW:
2381         case AUDIT_OBJ_LEV_HIGH:
2382                 rc = mls_from_string(rulestr, &tmprule->au_ctxt, GFP_ATOMIC);
2383                 break;
2384         }
2385
2386         POLICY_RDUNLOCK;
2387
2388         if (rc) {
2389                 selinux_audit_rule_free(tmprule);
2390                 tmprule = NULL;
2391         }
2392
2393         *rule = tmprule;
2394
2395         return rc;
2396 }
2397
2398 /* Check to see if the rule contains any selinux fields */
2399 int selinux_audit_rule_known(struct audit_krule *rule)
2400 {
2401         int i;
2402
2403         for (i = 0; i < rule->field_count; i++) {
2404                 struct audit_field *f = &rule->fields[i];
2405                 switch (f->type) {
2406                 case AUDIT_SUBJ_USER:
2407                 case AUDIT_SUBJ_ROLE:
2408                 case AUDIT_SUBJ_TYPE:
2409                 case AUDIT_SUBJ_SEN:
2410                 case AUDIT_SUBJ_CLR:
2411                 case AUDIT_OBJ_USER:
2412                 case AUDIT_OBJ_ROLE:
2413                 case AUDIT_OBJ_TYPE:
2414                 case AUDIT_OBJ_LEV_LOW:
2415                 case AUDIT_OBJ_LEV_HIGH:
2416                         return 1;
2417                 }
2418         }
2419
2420         return 0;
2421 }
2422
2423 int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule,
2424                              struct audit_context *actx)
2425 {
2426         struct context *ctxt;
2427         struct mls_level *level;
2428         struct selinux_audit_rule *rule = vrule;
2429         int match = 0;
2430
2431         if (!rule) {
2432                 audit_log(actx, GFP_ATOMIC, AUDIT_SELINUX_ERR,
2433                           "selinux_audit_rule_match: missing rule\n");
2434                 return -ENOENT;
2435         }
2436
2437         POLICY_RDLOCK;
2438
2439         if (rule->au_seqno < latest_granting) {
2440                 audit_log(actx, GFP_ATOMIC, AUDIT_SELINUX_ERR,
2441                           "selinux_audit_rule_match: stale rule\n");
2442                 match = -ESTALE;
2443                 goto out;
2444         }
2445
2446         ctxt = sidtab_search(&sidtab, sid);
2447         if (!ctxt) {
2448                 audit_log(actx, GFP_ATOMIC, AUDIT_SELINUX_ERR,
2449                           "selinux_audit_rule_match: unrecognized SID %d\n",
2450                           sid);
2451                 match = -ENOENT;
2452                 goto out;
2453         }
2454
2455         /* a field/op pair that is not caught here will simply fall through
2456            without a match */
2457         switch (field) {
2458         case AUDIT_SUBJ_USER:
2459         case AUDIT_OBJ_USER:
2460                 switch (op) {
2461                 case AUDIT_EQUAL:
2462                         match = (ctxt->user == rule->au_ctxt.user);
2463                         break;
2464                 case AUDIT_NOT_EQUAL:
2465                         match = (ctxt->user != rule->au_ctxt.user);
2466                         break;
2467                 }
2468                 break;
2469         case AUDIT_SUBJ_ROLE:
2470         case AUDIT_OBJ_ROLE:
2471                 switch (op) {
2472                 case AUDIT_EQUAL:
2473                         match = (ctxt->role == rule->au_ctxt.role);
2474                         break;
2475                 case AUDIT_NOT_EQUAL:
2476                         match = (ctxt->role != rule->au_ctxt.role);
2477                         break;
2478                 }
2479                 break;
2480         case AUDIT_SUBJ_TYPE:
2481         case AUDIT_OBJ_TYPE:
2482                 switch (op) {
2483                 case AUDIT_EQUAL:
2484                         match = (ctxt->type == rule->au_ctxt.type);
2485                         break;
2486                 case AUDIT_NOT_EQUAL:
2487                         match = (ctxt->type != rule->au_ctxt.type);
2488                         break;
2489                 }
2490                 break;
2491         case AUDIT_SUBJ_SEN:
2492         case AUDIT_SUBJ_CLR:
2493         case AUDIT_OBJ_LEV_LOW:
2494         case AUDIT_OBJ_LEV_HIGH:
2495                 level = ((field == AUDIT_SUBJ_SEN ||
2496                           field == AUDIT_OBJ_LEV_LOW) ?
2497                          &ctxt->range.level[0] : &ctxt->range.level[1]);
2498                 switch (op) {
2499                 case AUDIT_EQUAL:
2500                         match = mls_level_eq(&rule->au_ctxt.range.level[0],
2501                                              level);
2502                         break;
2503                 case AUDIT_NOT_EQUAL:
2504                         match = !mls_level_eq(&rule->au_ctxt.range.level[0],
2505                                               level);
2506                         break;
2507                 case AUDIT_LESS_THAN:
2508                         match = (mls_level_dom(&rule->au_ctxt.range.level[0],
2509                                                level) &&
2510                                  !mls_level_eq(&rule->au_ctxt.range.level[0],
2511                                                level));
2512                         break;
2513                 case AUDIT_LESS_THAN_OR_EQUAL:
2514                         match = mls_level_dom(&rule->au_ctxt.range.level[0],
2515                                               level);
2516                         break;
2517                 case AUDIT_GREATER_THAN:
2518                         match = (mls_level_dom(level,
2519                                               &rule->au_ctxt.range.level[0]) &&
2520                                  !mls_level_eq(level,
2521                                                &rule->au_ctxt.range.level[0]));
2522                         break;
2523                 case AUDIT_GREATER_THAN_OR_EQUAL:
2524                         match = mls_level_dom(level,
2525                                               &rule->au_ctxt.range.level[0]);
2526                         break;
2527                 }
2528         }
2529
2530 out:
2531         POLICY_RDUNLOCK;
2532         return match;
2533 }
2534
2535 static int (*aurule_callback)(void) = audit_update_lsm_rules;
2536
2537 static int aurule_avc_callback(u32 event, u32 ssid, u32 tsid,
2538                                u16 class, u32 perms, u32 *retained)
2539 {
2540         int err = 0;
2541
2542         if (event == AVC_CALLBACK_RESET && aurule_callback)
2543                 err = aurule_callback();
2544         return err;
2545 }
2546
2547 static int __init aurule_init(void)
2548 {
2549         int err;
2550
2551         err = avc_add_callback(aurule_avc_callback, AVC_CALLBACK_RESET,
2552                                SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0);
2553         if (err)
2554                 panic("avc_add_callback() failed, error %d\n", err);
2555
2556         return err;
2557 }
2558 __initcall(aurule_init);
2559
2560 #ifdef CONFIG_NETLABEL
2561 /**
2562  * security_netlbl_cache_add - Add an entry to the NetLabel cache
2563  * @secattr: the NetLabel packet security attributes
2564  * @sid: the SELinux SID
2565  *
2566  * Description:
2567  * Attempt to cache the context in @ctx, which was derived from the packet in
2568  * @skb, in the NetLabel subsystem cache.  This function assumes @secattr has
2569  * already been initialized.
2570  *
2571  */
2572 static void security_netlbl_cache_add(struct netlbl_lsm_secattr *secattr,
2573                                       u32 sid)
2574 {
2575         u32 *sid_cache;
2576
2577         sid_cache = kmalloc(sizeof(*sid_cache), GFP_ATOMIC);
2578         if (sid_cache == NULL)
2579                 return;
2580         secattr->cache = netlbl_secattr_cache_alloc(GFP_ATOMIC);
2581         if (secattr->cache == NULL) {
2582                 kfree(sid_cache);
2583                 return;
2584         }
2585
2586         *sid_cache = sid;
2587         secattr->cache->free = kfree;
2588         secattr->cache->data = sid_cache;
2589         secattr->flags |= NETLBL_SECATTR_CACHE;
2590 }
2591
2592 /**
2593  * security_netlbl_secattr_to_sid - Convert a NetLabel secattr to a SELinux SID
2594  * @secattr: the NetLabel packet security attributes
2595  * @sid: the SELinux SID
2596  *
2597  * Description:
2598  * Convert the given NetLabel security attributes in @secattr into a
2599  * SELinux SID.  If the @secattr field does not contain a full SELinux
2600  * SID/context then use SECINITSID_NETMSG as the foundation.  If possibile the
2601  * 'cache' field of @secattr is set and the CACHE flag is set; this is to
2602  * allow the @secattr to be used by NetLabel to cache the secattr to SID
2603  * conversion for future lookups.  Returns zero on success, negative values on
2604  * failure.
2605  *
2606  */
2607 int security_netlbl_secattr_to_sid(struct netlbl_lsm_secattr *secattr,
2608                                    u32 *sid)
2609 {
2610         int rc = -EIDRM;
2611         struct context *ctx;
2612         struct context ctx_new;
2613
2614         if (!ss_initialized) {
2615                 *sid = SECSID_NULL;
2616                 return 0;
2617         }
2618
2619         POLICY_RDLOCK;
2620
2621         if (secattr->flags & NETLBL_SECATTR_CACHE) {
2622                 *sid = *(u32 *)secattr->cache->data;
2623                 rc = 0;
2624         } else if (secattr->flags & NETLBL_SECATTR_SECID) {
2625                 *sid = secattr->attr.secid;
2626                 rc = 0;
2627         } else if (secattr->flags & NETLBL_SECATTR_MLS_LVL) {
2628                 ctx = sidtab_search(&sidtab, SECINITSID_NETMSG);
2629                 if (ctx == NULL)
2630                         goto netlbl_secattr_to_sid_return;
2631
2632                 ctx_new.user = ctx->user;
2633                 ctx_new.role = ctx->role;
2634                 ctx_new.type = ctx->type;
2635                 mls_import_netlbl_lvl(&ctx_new, secattr);
2636                 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
2637                         if (ebitmap_netlbl_import(&ctx_new.range.level[0].cat,
2638                                                   secattr->attr.mls.cat) != 0)
2639                                 goto netlbl_secattr_to_sid_return;
2640                         ctx_new.range.level[1].cat.highbit =
2641                                 ctx_new.range.level[0].cat.highbit;
2642                         ctx_new.range.level[1].cat.node =
2643                                 ctx_new.range.level[0].cat.node;
2644                 } else {
2645                         ebitmap_init(&ctx_new.range.level[0].cat);
2646                         ebitmap_init(&ctx_new.range.level[1].cat);
2647                 }
2648                 if (mls_context_isvalid(&policydb, &ctx_new) != 1)
2649                         goto netlbl_secattr_to_sid_return_cleanup;
2650
2651                 rc = sidtab_context_to_sid(&sidtab, &ctx_new, sid);
2652                 if (rc != 0)
2653                         goto netlbl_secattr_to_sid_return_cleanup;
2654
2655                 security_netlbl_cache_add(secattr, *sid);
2656
2657                 ebitmap_destroy(&ctx_new.range.level[0].cat);
2658         } else {
2659                 *sid = SECSID_NULL;
2660                 rc = 0;
2661         }
2662
2663 netlbl_secattr_to_sid_return:
2664         POLICY_RDUNLOCK;
2665         return rc;
2666 netlbl_secattr_to_sid_return_cleanup:
2667         ebitmap_destroy(&ctx_new.range.level[0].cat);
2668         goto netlbl_secattr_to_sid_return;
2669 }
2670
2671 /**
2672  * security_netlbl_sid_to_secattr - Convert a SELinux SID to a NetLabel secattr
2673  * @sid: the SELinux SID
2674  * @secattr: the NetLabel packet security attributes
2675  *
2676  * Description:
2677  * Convert the given SELinux SID in @sid into a NetLabel security attribute.
2678  * Returns zero on success, negative values on failure.
2679  *
2680  */
2681 int security_netlbl_sid_to_secattr(u32 sid, struct netlbl_lsm_secattr *secattr)
2682 {
2683         int rc = -ENOENT;
2684         struct context *ctx;
2685
2686         if (!ss_initialized)
2687                 return 0;
2688
2689         POLICY_RDLOCK;
2690         ctx = sidtab_search(&sidtab, sid);
2691         if (ctx == NULL)
2692                 goto netlbl_sid_to_secattr_failure;
2693         secattr->domain = kstrdup(policydb.p_type_val_to_name[ctx->type - 1],
2694                                   GFP_ATOMIC);
2695         secattr->flags |= NETLBL_SECATTR_DOMAIN_CPY;
2696         mls_export_netlbl_lvl(ctx, secattr);
2697         rc = mls_export_netlbl_cat(ctx, secattr);
2698         if (rc != 0)
2699                 goto netlbl_sid_to_secattr_failure;
2700         POLICY_RDUNLOCK;
2701
2702         return 0;
2703
2704 netlbl_sid_to_secattr_failure:
2705         POLICY_RDUNLOCK;
2706         return rc;
2707 }
2708 #endif /* CONFIG_NETLABEL */