OSX/libsecurity_codesigning/lib/policydb.cpp

   1 /*
   2  * Copyright (c) 2011-2013 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 #include "cs.h"
  24 #include "policydb.h"
  25 #include "policyengine.h"
  26 #include <Security/CodeSigning.h>
  27 #include <security_utilities/cfutilities.h>
  28 #include <security_utilities/cfmunge.h>
  29 #include <security_utilities/blob.h>
  30 #include <security_utilities/logging.h>
  31 #include <security_utilities/simpleprefs.h>
  32 #include <security_utilities/logging.h>
  33 #include "csdatabase.h"
  34
  35 #include <dispatch/dispatch.h>
  36 #include <sys/types.h>
  37 #include <sys/stat.h>
  38 #include <notify.h>
  39
  40 namespace Security {
  41 namespace CodeSigning {
  42
  43
  44 using namespace SQLite;
  45
  46
  47 //
  48 // Determine the database path
  49 //
  50 static const char *dbPath()
  51 {
  52         if (const char *s = getenv("SYSPOLICYDATABASE"))
  53                 return s;
  54         return defaultDatabase;
  55 }
  56
  57
  58 //
  59 // Help mapping API-ish CFString keys to more convenient internal enumerations
  60 //
  61 typedef struct {
  62         const CFStringRef &cstring;
  63         uint enumeration;
  64 } StringMap;
  65
  66 static uint mapEnum(CFDictionaryRef context, CFStringRef attr, const StringMap *map, uint value = 0)
  67 {
  68         if (context)
  69                 if (CFTypeRef value = CFDictionaryGetValue(context, attr))
  70                         for (const StringMap *mp = map; mp->cstring; ++mp)
  71                                 if (CFEqual(mp->cstring, value))
  72                                         return mp->enumeration;
  73         return value;
  74 }
  75
  76 static const StringMap mapType[] = {
  77         { kSecAssessmentOperationTypeExecute, kAuthorityExecute },
  78         { kSecAssessmentOperationTypeInstall, kAuthorityInstall },
  79         { kSecAssessmentOperationTypeOpenDocument, kAuthorityOpenDoc },
  80         { NULL }
  81 };
  82
  83 AuthorityType typeFor(CFDictionaryRef context, AuthorityType type /* = kAuthorityInvalid */)
  84 {
  85         return mapEnum(context, kSecAssessmentContextKeyOperation, mapType, type);
  86 }
  87
  88 CFStringRef typeNameFor(AuthorityType type)
  89 {
  90         for (const StringMap *mp = mapType; mp->cstring; ++mp)
  91                 if (type == mp->enumeration)
  92                         return mp->cstring;
  93         return CFStringCreateWithFormat(NULL, NULL, CFSTR("type %d"), type);
  94 }
  95
  96
  97 //
  98 // Open the database
  99 //
 100 PolicyDatabase::PolicyDatabase(const char *path, int flags)
 101         : SQLite::Database(path ? path : dbPath(), flags),
 102           mLastExplicitCheck(0)
 103 {
 104         // sqlite3 doesn't do foreign key support by default, have to turn this on per connection
 105         SQLite::Statement foreign(*this, "PRAGMA foreign_keys = true");
 106         foreign.execute();
 107
 108         // Try upgrade processing if we may be open for write.
 109         // Ignore any errors (we may have been downgraded to read-only)
 110         // and try again later.
 111         if (openFlags() & SQLITE_OPEN_READWRITE)
 112                 try {
 113                         upgradeDatabase();
 114                         installExplicitSet(gkeAuthFile, gkeSigsFile);
 115                 } catch(...) {
 116                 }
 117 }
 118
 119 PolicyDatabase::~PolicyDatabase()
 120 { /* virtual */ }
 121
 122
 123 //
 124 // Quick-check the cache for a match.
 125 // Return true on a cache hit, false on failure to confirm a hit for any reason.
 126 //
 127 bool PolicyDatabase::checkCache(CFURLRef path, AuthorityType type, SecAssessmentFlags flags, CFMutableDictionaryRef result)
 128 {
 129         // we currently don't use the cache for anything but execution rules
 130         if (type != kAuthorityExecute)
 131                 return false;
 132
 133         CFRef<SecStaticCodeRef> code;
 134         MacOSError::check(SecStaticCodeCreateWithPath(path, kSecCSDefaultFlags, &code.aref()));
 135         if (SecStaticCodeCheckValidity(code, kSecCSBasicValidateOnly, NULL) != errSecSuccess)
 136                 return false;   // quick pass - any error is a cache miss
 137         CFRef<CFDictionaryRef> info;
 138         MacOSError::check(SecCodeCopySigningInformation(code, kSecCSDefaultFlags, &info.aref()));
 139         CFDataRef cdHash = CFDataRef(CFDictionaryGetValue(info, kSecCodeInfoUnique));
 140
 141         // check the cache table for a fast match
 142         SQLite::Statement cached(*this, "SELECT object.allow, authority.label, authority FROM object, authority"
 143                 " WHERE object.authority = authority.id AND object.type = :type AND object.hash = :hash AND authority.disabled = 0"
 144                 " AND JULIANDAY('now') < object.expires;");
 145         cached.bind(":type").integer(type);
 146         cached.bind(":hash") = cdHash;
 147         if (cached.nextRow()) {
 148                 bool allow = int(cached[0]);
 149                 const char *label = cached[1];
 150                 SQLite::int64 auth = cached[2];
 151                 SYSPOLICY_ASSESS_CACHE_HIT();
 152
 153                 // If its allowed, lets do a full validation unless if
 154                 // we are overriding the assessement, since that force
 155                 // the verdict to 'pass' at the end
 156
 157                 if (allow && !overrideAssessment(flags))
 158                     MacOSError::check(SecStaticCodeCheckValidity(code, kSecCSDefaultFlags, NULL));
 159
 160                 cfadd(result, "{%O=%B}", kSecAssessmentAssessmentVerdict, allow);
 161                 PolicyEngine::addAuthority(flags, result, label, auth, kCFBooleanTrue);
 162                 return true;
 163         }
 164         return false;
 165 }
 166
 167
 168 //
 169 // Purge the object cache of all expired entries.
 170 // These are meant to run within the caller's transaction.
 171 //
 172 void PolicyDatabase::purgeAuthority()
 173 {
 174         SQLite::Statement cleaner(*this,
 175                 "DELETE FROM authority WHERE expires <= JULIANDAY('now');");
 176         cleaner.execute();
 177 }
 178
 179 void PolicyDatabase::purgeObjects()
 180 {
 181         SQLite::Statement cleaner(*this,
 182                 "DELETE FROM object WHERE expires <= JULIANDAY('now');");
 183         cleaner.execute();
 184 }
 185
 186 void PolicyDatabase::purgeObjects(double priority)
 187 {
 188         SQLite::Statement cleaner(*this,
 189                 "DELETE FROM object WHERE expires <= JULIANDAY('now') OR (SELECT priority FROM authority WHERE id = object.authority) <= :priority;");
 190         cleaner.bind(":priority") = priority;
 191         cleaner.execute();
 192 }
 193
 194
 195 //
 196 // Database migration
 197 //
 198 std::string PolicyDatabase::featureLevel(const char *name)
 199 {
 200         SQLite::Statement feature(*this, "SELECT value FROM feature WHERE name=:name");
 201         feature.bind(":name") = name;
 202         if (feature.nextRow()) {
 203                 if (const char *value = feature[0])
 204                         return value;
 205                 else
 206                         return "default";       // old engineering versions may have NULL values; tolerate this
 207         }
 208         return "";              // new feature (no level)
 209 }
 210
 211 void PolicyDatabase::addFeature(const char *name, const char *value, const char *remarks)
 212 {
 213         SQLite::Statement feature(*this, "INSERT OR REPLACE INTO feature (name,value,remarks) VALUES(:name, :value, :remarks)");
 214         feature.bind(":name") = name;
 215         feature.bind(":value") = value;
 216         feature.bind(":remarks") = remarks;
 217         feature.execute();
 218 }
 219
 220 void PolicyDatabase::simpleFeature(const char *feature, void (^perform)())
 221 {
 222         if (!hasFeature(feature)) {
 223                 SQLite::Transaction update(*this);
 224                 perform();
 225                 addFeature(feature, "upgraded", "upgraded");
 226                 update.commit();
 227         }
 228 }
 229
 230 void PolicyDatabase::simpleFeature(const char *feature, const char *sql)
 231 {
 232         simpleFeature(feature, ^{
 233                 SQLite::Statement perform(*this, sql);
 234                 perform.execute();
 235         });
 236 }
 237
 238
 239 void PolicyDatabase::upgradeDatabase()
 240 {
 241         simpleFeature("bookmarkhints",
 242                 "CREATE TABLE bookmarkhints ("
 243                         "  id INTEGER PRIMARY KEY AUTOINCREMENT, "
 244                         "  bookmark BLOB,"
 245                         "  authority INTEGER NOT NULL"
 246                         "     REFERENCES authority(id) ON DELETE CASCADE"
 247                         ")");
 248
 249         simpleFeature("codesignedpackages", ^{
 250                 SQLite::Statement update(*this,
 251                         "UPDATE authority"
 252                         " SET requirement = 'anchor apple generic and certificate 1[field.1.2.840.113635.100.6.2.6] exists and "
 253                                 "(certificate leaf[field.1.2.840.113635.100.6.1.14] or certificate leaf[field.1.2.840.113635.100.6.1.13])'"
 254                         " WHERE type = 2 and label = 'Developer ID' and flags & :flag");
 255                 update.bind(":flag") = kAuthorityFlagDefault;
 256                 update.execute();
 257         });
 258
 259         simpleFeature("filter_unsigned",
 260                 "ALTER TABLE authority ADD COLUMN filter_unsigned TEXT NULL"
 261                 );
 262
 263         simpleFeature("strict_apple_installer", ^{
 264                 SQLite::Statement update(*this,
 265                         "UPDATE authority"
 266                         " SET requirement = 'anchor apple generic and certificate 1[subject.CN] = \"Apple Software Update Certification Authority\"'"
 267                         " WHERE flags & :flag AND label = 'Apple Installer'");
 268                 update.bind(":flag") = kAuthorityFlagDefault;
 269                 update.execute();
 270                 SQLite::Statement add(*this,
 271                         "INSERT INTO authority (type, label, flags, requirement)"
 272                         " VALUES (2, 'Mac App Store', :flags, 'anchor apple generic and certificate leaf[field.1.2.840.113635.100.6.1.10] exists')");
 273                 add.bind(":flags") = kAuthorityFlagDefault;
 274                 add.execute();
 275         });
 276
 277         simpleFeature("document rules", ^{
 278                 SQLite::Statement addApple(*this,
 279                         "INSERT INTO authority (type, allow, flags, label, requirement) VALUES (3, 1, 2, 'Apple System', 'anchor apple')");
 280                 addApple.execute();
 281                 SQLite::Statement addDevID(*this,
 282                         "INSERT INTO authority (type, allow, flags, label, requirement) VALUES (3, 1, 2, 'Developer ID', 'anchor apple generic and certificate 1[field.1.2.840.113635.100.6.2.6] exists and certificate leaf[field.1.2.840.113635.100.6.1.13] exists')");
 283                 addDevID.execute();
 284         });
 285 }
 286
 287
 288 //
 289 // Install Gatekeeper override (GKE) data.
 290 // The arguments are paths to the authority and signature files.
 291 //
 292 void PolicyDatabase::installExplicitSet(const char *authfile, const char *sigfile)
 293 {
 294         // only try this every gkeCheckInterval seconds
 295         time_t now = time(NULL);
 296         if (mLastExplicitCheck + gkeCheckInterval > now)
 297                 return;
 298         mLastExplicitCheck = now;
 299
 300         try {
 301                 if (CFRef<CFDataRef> authData = cfLoadFile(authfile)) {
 302                         CFDictionary auth(CFRef<CFDictionaryRef>(makeCFDictionaryFrom(authData)), errSecCSDbCorrupt);
 303                         CFDictionaryRef content = auth.get<CFDictionaryRef>(CFSTR("authority"));
 304                         std::string authUUID = cfString(auth.get<CFStringRef>(CFSTR("uuid")));
 305                         if (authUUID.empty()) {
 306                                 secdebug("gkupgrade", "no uuid in auth file; ignoring gke.auth");
 307                                 return;
 308                         }
 309                         std::string dbUUID;
 310                         SQLite::Statement uuidQuery(*this, "SELECT value FROM feature WHERE name='gke'");
 311                         if (uuidQuery.nextRow())
 312                                 dbUUID = (const char *)uuidQuery[0];
 313                         if (dbUUID == authUUID) {
 314                                 secdebug("gkupgrade", "gke.auth already present, ignoring");
 315                                 return;
 316                         }
 317                         Syslog::notice("loading GKE %s (replacing %s)", authUUID.c_str(), dbUUID.empty() ? "nothing" : dbUUID.c_str());
 318
 319                         // first, load code signatures. This is pretty much idempotent
 320                         if (sigfile)
 321                                 if (FILE *sigs = fopen(sigfile, "r")) {
 322                                         unsigned count = 0;
 323                                     SignatureDatabaseWriter db;
 324                                         while (const BlobCore *blob = BlobCore::readBlob(sigs)) {
 325                                                 db.storeCode(blob, "<remote>");
 326                                                 count++;
 327                                         }
 328                                         secdebug("gkupgrade", "%d detached signature(s) loaded from override data", count);
 329                                         fclose(sigs);
 330                                 }
 331
 332                         // start transaction (atomic from here on out)
 333                         SQLite::Transaction loadAuth(*this, SQLite::Transaction::exclusive, "GKE_Upgrade");
 334
 335                         // purge prior authority data
 336                         SQLite::Statement purge(*this, "DELETE FROM authority WHERE flags & :flag");
 337                         purge.bind(":flag") = kAuthorityFlagWhitelist;
 338                         purge();
 339
 340                         // load new data
 341                         CFIndex count = CFDictionaryGetCount(content);
 342                         CFStringRef keys[count];
 343                         CFDictionaryRef values[count];
 344                         CFDictionaryGetKeysAndValues(content, (const void **)keys, (const void **)values);
 345
 346                         SQLite::Statement insert(*this, "INSERT INTO authority (type, allow, requirement, label, filter_unsigned, flags, remarks)"
 347                                 " VALUES (:type, 1, :requirement, 'GKE', :filter, :flags, :path)");
 348                         for (CFIndex n = 0; n < count; n++) {
 349                                 CFDictionary info(values[n], errSecCSDbCorrupt);
 350                                 uint32_t flags = kAuthorityFlagWhitelist;
 351                                 if (CFNumberRef versionRef = info.get<CFNumberRef>("version")) {
 352                                         int version = cfNumber<int>(versionRef);
 353                                         if (version >= 2)
 354                                                 flags |= kAuthorityFlagWhitelistV2;
 355                                 }
 356                                 insert.reset();
 357                                 insert.bind(":type") = cfString(info.get<CFStringRef>(CFSTR("type")));
 358                                 insert.bind(":path") = cfString(info.get<CFStringRef>(CFSTR("path")));
 359                                 insert.bind(":requirement") = "cdhash H\"" + cfString(info.get<CFStringRef>(CFSTR("cdhash"))) + "\"";
 360                                 insert.bind(":filter") = cfString(info.get<CFStringRef>(CFSTR("screen")));
 361                                 insert.bind(":flags").integer(flags);
 362                                 insert();
 363                         }
 364
 365                         // we just changed the authority configuration at priority zero
 366                         this->purgeObjects(0);
 367
 368                         // update version and commit
 369                         addFeature("gke", authUUID.c_str(), "gke loaded");
 370                         loadAuth.commit();
 371                 }
 372         } catch (...) {
 373                 secdebug("gkupgrade", "exception during GKE upgrade");
 374         }
 375 }
 376
 377
 378 //
 379 // Check the override-enable master flag
 380 //
 381 #define SP_ENABLE_KEY CFSTR("enabled")
 382 #define SP_ENABLED CFSTR("yes")
 383 #define SP_DISABLED CFSTR("no")
 384
 385 bool overrideAssessment(SecAssessmentFlags flags /* = 0 */)
 386 {
 387         static bool enabled = true;
 388         static dispatch_once_t once;
 389         static int token = -1;
 390         static int have_token = 0;
 391         static dispatch_queue_t queue;
 392         int check;
 393
 394         if (flags & kSecAssessmentFlagEnforce)  // explicitly disregard disables (force on)
 395                 return false;
 396
 397         if (have_token && notify_check(token, &check) == NOTIFY_STATUS_OK && !check)
 398                 return !enabled;
 399
 400         dispatch_once(&once, ^{
 401                 if (notify_register_check(kNotifySecAssessmentMasterSwitch, &token) == NOTIFY_STATUS_OK)
 402                         have_token = 1;
 403                 queue = dispatch_queue_create("com.apple.SecAssessment.assessment", NULL);
 404              });
 405
 406         dispatch_sync(queue, ^{
 407                 /* upgrade configuration from emir, ignore all error since we might not be able to write to */
 408                 if (::access(visibleSecurityFlagFile, F_OK) == 0) {
 409                         try {
 410                                 setAssessment(true);
 411                                 ::unlink(visibleSecurityFlagFile);
 412                         } catch (...) {
 413                         }
 414                         enabled = true;
 415                         return;
 416                 }
 417
 418                 try {
 419                         Dictionary * prefsDict = Dictionary::CreateDictionary(prefsFile);
 420                         if (prefsDict == NULL)
 421                                 return;
 422
 423                         CFStringRef value = prefsDict->getStringValue(SP_ENABLE_KEY);
 424                         if (value && CFStringCompare(value, SP_DISABLED, 0) == 0)
 425                                 enabled = false;
 426                         else
 427                                 enabled = true;
 428                         delete prefsDict;
 429                 } catch(...) {
 430                 }
 431         });
 432
 433         return !enabled;
 434 }
 435
 436 void setAssessment(bool masterSwitch)
 437 {
 438         MutableDictionary *prefsDict = MutableDictionary::CreateMutableDictionary(prefsFile);
 439         if (prefsDict == NULL)
 440                 prefsDict = new MutableDictionary::MutableDictionary();
 441         prefsDict->setValue(SP_ENABLE_KEY, masterSwitch ? SP_ENABLED : SP_DISABLED);
 442         prefsDict->writePlistToFile(prefsFile);
 443         delete prefsDict;
 444
 445         /* make sure permissions is right */
 446         ::chmod(prefsFile, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
 447
 448         notify_post(kNotifySecAssessmentMasterSwitch);
 449
 450         /* reset the automatic rearm timer */
 451         resetRearmTimer("masterswitch");
 452 }
 453
 454
 455 //
 456 // Reset or query the automatic rearm timer
 457 //
 458 void resetRearmTimer(const char *event)
 459 {
 460         CFRef<CFDateRef> now = CFDateCreate(NULL, CFAbsoluteTimeGetCurrent());
 461         CFTemp<CFDictionaryRef> info("{event=%s, timestamp=%O}", event, now.get());
 462         CFRef<CFDataRef> infoData = makeCFData(info.get());
 463         UnixPlusPlus::AutoFileDesc fd(rearmTimerFile, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 464         fd.write(CFDataGetBytePtr(infoData), CFDataGetLength(infoData));
 465 }
 466
 467 bool queryRearmTimer(CFTimeInterval &delta)
 468 {
 469         if (CFRef<CFDataRef> infoData = cfLoadFile(rearmTimerFile)) {
 470                 if (CFRef<CFDictionaryRef> info = makeCFDictionaryFrom(infoData)) {
 471                         CFDateRef timestamp = (CFDateRef)CFDictionaryGetValue(info, CFSTR("timestamp"));
 472                         if (timestamp && CFGetTypeID(timestamp) == CFDateGetTypeID()) {
 473                                 delta = CFAbsoluteTimeGetCurrent() - CFDateGetAbsoluteTime(timestamp);
 474                                 return true;
 475                         }
 476                 }
 477                 MacOSError::throwMe(errSecCSDbCorrupt);
 478         }
 479         return false;
 480 }
 481
 482
 483 } // end namespace CodeSigning
 484 } // end namespace Security