OSX/libsecurity_codesigning/lib/resources.cpp

   1 /*
   2  * Copyright (c) 2006-2014 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,
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  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
  24 //
  25 // resource directory construction and verification
  26 //
  27 #include "resources.h"
  28 #include "csutilities.h"
  29 #include <security_utilities/unix++.h>
  30 #include <security_utilities/debugging.h>
  31 #include <Security/CSCommon.h>
  32 #include <security_utilities/unix++.h>
  33 #include <security_utilities/cfmunge.h>
  34
  35 // These are pretty nasty, but are a quick safe fix
  36 // to pass information down to the gatekeeper collection tool
  37 extern "C" {
  38     int GKBIS_DS_Store_Present;
  39         int GKBIS_Dot_underbar_Present;
  40         int GKBIS_Num_localizations;
  41         int GKBIS_Num_files;
  42         int GKBIS_Num_dirs;
  43         int GKBIS_Num_symlinks;
  44 }
  45
  46 namespace Security {
  47 namespace CodeSigning {
  48
  49
  50 static string removeTrailingSlash(string path)
  51 {
  52         if (path.substr(path.length()-2, 2) == "/.")
  53                 return path.substr(0, path.length()-2);
  54         else if (path.substr(path.length()-1, 1) == "/")
  55                 return path.substr(0, path.length()-1);
  56         else
  57                 return path;
  58 }
  59
  60 //
  61 // Construction and maintainance
  62 //
  63 ResourceBuilder::ResourceBuilder(const std::string &root, const std::string &relBase,
  64         CFDictionaryRef rulesDict, bool strict, const MacOSErrorSet& toleratedErrors)
  65         : mCheckUnreadable(strict && toleratedErrors.find(errSecCSSignatureNotVerifiable) == toleratedErrors.end()),
  66           mCheckUnknownType(strict && toleratedErrors.find(errSecCSResourceNotSupported) == toleratedErrors.end())
  67 {
  68         assert(!root.empty());
  69         char realroot[PATH_MAX];
  70         if (realpath(root.c_str(), realroot) == NULL)
  71                 UnixError::throwMe();
  72         mRoot = realroot;
  73         if (realpath(removeTrailingSlash(relBase).c_str(), realroot) == NULL)
  74                 UnixError::throwMe();
  75         mRelBase = realroot;
  76         if (mRoot != mRelBase && mRelBase != mRoot + "/Contents")
  77                 MacOSError::throwMe(errSecCSBadBundleFormat);
  78         const char * paths[2] = { mRoot.c_str(), NULL };
  79         mFTS = fts_open((char * const *)paths, FTS_PHYSICAL | FTS_COMFOLLOW | FTS_NOCHDIR, NULL);
  80         if (!mFTS)
  81                 UnixError::throwMe();
  82         mRawRules = rulesDict;
  83         CFDictionary rules(rulesDict, errSecCSResourceRulesInvalid);
  84         rules.apply(this, &ResourceBuilder::addRule);
  85 }
  86
  87 ResourceBuilder::~ResourceBuilder()
  88 {
  89         for (Rules::iterator it = mRules.begin(); it != mRules.end(); ++it)
  90                 delete *it;
  91         fts_close(mFTS);        // do not check error - it's not worth aborting over (double fault etc.)
  92 }
  93
  94
  95 //
  96 // Parse and add one matching rule
  97 //
  98 void ResourceBuilder::addRule(CFTypeRef key, CFTypeRef value)
  99 {
 100         string pattern = cfString(key, errSecCSResourceRulesInvalid);
 101         unsigned weight = 1;
 102         uint32_t flags = 0;
 103         if (CFGetTypeID(value) == CFBooleanGetTypeID()) {
 104                 if (value == kCFBooleanFalse)
 105                         flags |= omitted;
 106         } else {
 107                 CFDictionary rule(value, errSecCSResourceRulesInvalid);
 108                 if (CFNumberRef weightRef = rule.get<CFNumberRef>("weight"))
 109                         weight = cfNumber<unsigned int>(weightRef);
 110                 if (CFBooleanRef omitRef = rule.get<CFBooleanRef>("omit"))
 111                         if (omitRef == kCFBooleanTrue)
 112                                 flags |= omitted;
 113                 if (CFBooleanRef optRef = rule.get<CFBooleanRef>("optional"))
 114                         if (optRef == kCFBooleanTrue)
 115                                 flags |= optional;
 116                 if (CFBooleanRef nestRef = rule.get<CFBooleanRef>("nested"))
 117                         if (nestRef == kCFBooleanTrue)
 118                                 flags |= nested;
 119         }
 120         addRule(new Rule(pattern, weight, flags));
 121 }
 122
 123 static bool findStringEndingNoCase(const char *path, const char * end)
 124 {
 125     size_t len_path = strlen(path);
 126     size_t len_end = strlen(end);
 127
 128     if (len_path >= len_end) {
 129         return strcasecmp(path + (len_path - len_end), end) == 0;
 130     } else
 131         return false;
 132 }
 133
 134 //
 135 // Locate the next non-ignored file, look up its rule, and return it.
 136 // Returns NULL when we're out of files.
 137 //
 138 void ResourceBuilder::scan(Scanner next)
 139 {
 140         bool first = true;
 141
 142         while (FTSENT *ent = fts_read(mFTS)) {
 143                 static const char ds_store[] = ".DS_Store";
 144                 const char *relpath = ent->fts_path + mRoot.size() + 1; // skip prefix + "/"
 145                 std::string rp;
 146                 if (mRelBase != mRoot) {
 147                         assert(mRelBase == mRoot + "/Contents");
 148                         rp = "../" + string(relpath);
 149                         if (rp.substr(0, 12) == "../Contents/")
 150                                 rp = rp.substr(12);
 151                         relpath = rp.c_str();
 152                 }
 153                 switch (ent->fts_info) {
 154                 case FTS_F:
 155                         secinfo("rdirenum", "file %s", ent->fts_path);
 156                         GKBIS_Num_files++;
 157
 158                         // These are checks for the gatekeeper collection
 159                         static const char underbar[] = "._";
 160                         if (strncasecmp(ent->fts_name, underbar, strlen(underbar)) == 0)
 161                                 GKBIS_Dot_underbar_Present++;
 162
 163                         if (strcasecmp(ent->fts_name, ds_store) == 0)
 164                                 GKBIS_DS_Store_Present++;
 165
 166                         if (Rule *rule = findRule(relpath))
 167                                 if (!(rule->flags & (omitted | exclusion)))
 168                                         next(ent, rule->flags, string(relpath), rule);
 169                         break;
 170                 case FTS_SL:
 171                         // symlinks cannot ever be nested code, so quietly convert to resource file
 172                         secinfo("rdirenum", "symlink %s", ent->fts_path);
 173                         GKBIS_Num_symlinks++;
 174
 175                         if (strcasecmp(ent->fts_name, ds_store) == 0)
 176                                 MacOSError::throwMe(errSecCSDSStoreSymlink);
 177
 178                         if (Rule *rule = findRule(relpath))
 179                                 if (!(rule->flags & (omitted | exclusion)))
 180                                         next(ent, rule->flags & ~nested, string(relpath), rule);
 181                         break;
 182                 case FTS_D:
 183                         secinfo("rdirenum", "entering %s", ent->fts_path);
 184                         GKBIS_Num_dirs++;
 185
 186                         if (!first) {   // skip root directory (relpath invalid)
 187                                 if (Rule *rule = findRule(relpath)) {
 188                                         if (rule->flags & nested) {
 189                                                 if (strchr(ent->fts_name, '.')) {       // nested, has extension -> treat as nested bundle
 190                                                         next(ent, rule->flags, string(relpath), rule);
 191                                                         fts_set(mFTS, ent, FTS_SKIP);
 192                                                 }
 193                                         } else if (rule->flags & exclusion) {   // exclude the whole directory
 194                                                 fts_set(mFTS, ent, FTS_SKIP);
 195                                         }
 196                                         // else treat as normal directory and descend into it
 197                                 }
 198                         }
 199                         // Report the number of localizations
 200                         if (findStringEndingNoCase(ent->fts_name, ".lproj"))
 201                                 GKBIS_Num_localizations++;
 202                         first = false;
 203
 204                         break;
 205                 case FTS_DP:
 206                         secinfo("rdirenum", "leaving %s", ent->fts_path);
 207                         break;
 208                 case FTS_DNR:
 209                         secinfo("rdirenum", "cannot read directory %s", ent->fts_path);
 210                         if (mCheckUnreadable)
 211                                 MacOSError::throwMe(errSecCSSignatureNotVerifiable);
 212                         break;
 213                 default:
 214                         secinfo("rdirenum", "type %d (errno %d): %s",
 215                                 ent->fts_info, ent->fts_errno, ent->fts_path);
 216                         if (mCheckUnknownType)
 217                                 MacOSError::throwMe(errSecCSResourceNotSupported);
 218                         break;
 219                 }
 220         }
 221 }
 222
 223
 224 //
 225 // Check a single for for inclusion in the resource envelope
 226 //
 227 bool ResourceBuilder::includes(string path) const
 228 {
 229         // process first-directory exclusions
 230         size_t firstslash = path.find('/');
 231         if (firstslash != string::npos)
 232                 if (Rule *rule = findRule(path.substr(0, firstslash)))
 233                         if (rule->flags & exclusion)
 234                                 return rule->flags & softTarget;
 235
 236         // process full match
 237         if (Rule *rule = findRule(path))
 238                 return !(rule->flags & (omitted | exclusion)) || (rule->flags & softTarget);
 239         else
 240                 return false;
 241 }
 242
 243
 244 //
 245 // Find the best-matching resource rule for an alleged resource file.
 246 // Returns NULL if no rule matches, or an exclusion rule applies.
 247 //
 248 ResourceBuilder::Rule *ResourceBuilder::findRule(string path) const
 249 {
 250         Rule *bestRule = NULL;
 251         secinfo("rscan", "test %s", path.c_str());
 252         for (Rules::const_iterator it = mRules.begin(); it != mRules.end(); ++it) {
 253                 Rule *rule = *it;
 254                 secinfo("rscan", "try %s", rule->source.c_str());
 255                 if (rule->match(path.c_str())) {
 256                         secinfo("rscan", "match");
 257                         if (rule->flags & exclusion) {
 258                                 secinfo("rscan", "excluded");
 259                                 return rule;
 260                         }
 261                         if (!bestRule || rule->weight > bestRule->weight)
 262                                 bestRule = rule;
 263
 264
 265 #if TARGET_OS_WATCH
 266 /* rdar://problem/30517969 */
 267                         if (bestRule && bestRule->weight == rule->weight && !(bestRule->flags & omitted) && (rule->flags & omitted))
 268                                 bestRule = rule;
 269 #endif
 270                 }
 271         }
 272         secinfo("rscan", "choosing %s (%d,0x%x)",
 273                 bestRule ? bestRule->source.c_str() : "NOTHING",
 274                 bestRule ? bestRule->weight : 0,
 275                 bestRule ? bestRule->flags : 0);
 276         return bestRule;
 277 }
 278
 279
 280 //
 281 // Hash a file and return a CFDataRef with the hash
 282 //
 283 CFDataRef ResourceBuilder::hashFile(const char *path, CodeDirectory::HashAlgorithm type)
 284 {
 285         UnixPlusPlus::AutoFileDesc fd(path);
 286         fd.fcntl(F_NOCACHE, true);              // turn off page caching (one-pass)
 287         RefPointer<DynamicHash> hasher(CodeDirectory::hashFor(type));
 288         hashFileData(fd, hasher.get());
 289         Hashing::Byte digest[hasher->digestLength()];
 290         hasher->finish(digest);
 291         return CFDataCreate(NULL, digest, sizeof(digest));
 292 }
 293
 294
 295 //
 296 // Hash a file to multiple hash types and return a dictionary suitable to form a resource seal
 297 //
 298 CFMutableDictionaryRef ResourceBuilder::hashFile(const char *path, CodeDirectory::HashAlgorithms types, bool strictCheck)
 299 {
 300         UnixPlusPlus::AutoFileDesc fd(path);
 301         fd.fcntl(F_NOCACHE, true);              // turn off page caching (one-pass)
 302         if (strictCheck)
 303                 if (fd.hasExtendedAttribute(XATTR_RESOURCEFORK_NAME) || fd.hasExtendedAttribute(XATTR_FINDERINFO_NAME))
 304                         MacOSError::throwMe(errSecCSInvalidAssociatedFileData);
 305         CFRef<CFMutableDictionaryRef> result = makeCFMutableDictionary();
 306         CFMutableDictionaryRef resultRef = result;
 307         CodeDirectory::multipleHashFileData(fd, 0, types, ^(CodeDirectory::HashAlgorithm type, Security::DynamicHash *hasher) {
 308                 size_t length = hasher->digestLength();
 309                 Hashing::Byte digest[length];
 310                 hasher->finish(digest);
 311                 CFDictionaryAddValue(resultRef, CFTempString(hashName(type)), CFTempData(digest, length));
 312         });
 313         return result.yield();
 314 }
 315
 316
 317 std::string ResourceBuilder::hashName(CodeDirectory::HashAlgorithm type)
 318 {
 319         switch (type) {
 320         case kSecCodeSignatureHashSHA1:
 321                 return "hash";
 322         default:
 323                 char name[20];
 324                 snprintf(name, sizeof(name), "hash%d", int(type));
 325                 return name;
 326         }
 327 }
 328
 329
 330 //
 331 // Regex matching objects
 332 //
 333 ResourceBuilder::Rule::Rule(const std::string &pattern, unsigned w, uint32_t f)
 334         : weight(w), flags(f), source(pattern)
 335 {
 336         if (::regcomp(this, pattern.c_str(), REG_EXTENDED | REG_NOSUB)) //@@@ REG_ICASE?
 337                 MacOSError::throwMe(errSecCSResourceRulesInvalid);
 338         secinfo("csresource", "%p rule %s added (weight %d, flags 0x%x)",
 339                 this, pattern.c_str(), w, f);
 340 }
 341
 342 ResourceBuilder::Rule::~Rule()
 343 {
 344         ::regfree(this);
 345 }
 346
 347 bool ResourceBuilder::Rule::match(const char *s) const
 348 {
 349         switch (::regexec(this, s, 0, NULL, 0)) {
 350         case 0:
 351                 return true;
 352         case REG_NOMATCH:
 353                 return false;
 354         default:
 355                 MacOSError::throwMe(errSecCSResourceRulesInvalid);
 356         }
 357 }
 358
 359
 360 std::string ResourceBuilder::escapeRE(const std::string &s)
 361 {
 362         string r;
 363         for (string::const_iterator it = s.begin(); it != s.end(); ++it) {
 364                 char c = *it;
 365                 if (strchr("\\[]{}().+*?^$|", c))
 366                         r.push_back('\\');
 367                 r.push_back(c);
 368         }
 369         return r;
 370 }
 371
 372
 373 //
 374 // Resource Seals
 375 //
 376 ResourceSeal::ResourceSeal(CFTypeRef it)
 377         : mDict(NULL), mRequirement(NULL), mLink(NULL), mFlags(0)
 378 {
 379         if (it == NULL)
 380                 MacOSError::throwMe(errSecCSResourcesInvalid);
 381         if (CFGetTypeID(it) == CFDataGetTypeID())       // old-style form with just a hash
 382                 mDict.take(cfmake<CFDictionaryRef>("{hash=%O}", it));
 383         else if (CFGetTypeID(it) == CFDictionaryGetTypeID())
 384                 mDict = CFDictionaryRef(it);
 385         else
 386                 MacOSError::throwMe(errSecCSResourcesInvalid);
 387
 388         int optional = 0;
 389         bool err;
 390         if (CFDictionaryGetValue(mDict, CFSTR("requirement")))
 391                 err = !cfscan(mDict, "{requirement=%SO,?optional=%B}", &mRequirement, &optional);
 392         else if (CFDictionaryGetValue(mDict, CFSTR("symlink")))
 393                 err = !cfscan(mDict, "{symlink=%SO,?optional=%B}", &mLink, &optional);
 394         else
 395                 err = !cfscan(mDict, "{?optional=%B}", &optional);
 396         if (err)
 397                 MacOSError::throwMe(errSecCSResourcesInvalid);
 398         if (optional)
 399                 mFlags |= ResourceBuilder::optional;
 400         if (mRequirement)
 401                 mFlags |= ResourceBuilder::nested;
 402 }
 403
 404
 405 const Hashing::Byte *ResourceSeal::hash(CodeDirectory::HashAlgorithm type) const
 406 {
 407         std::string name = ResourceBuilder::hashName(type);
 408         CFTypeRef hash = CFDictionaryGetValue(mDict, CFTempString(name));
 409         if (hash == NULL)       // pre-agility fallback
 410                 hash = CFDictionaryGetValue(mDict, CFSTR("hash"));
 411         if (hash == NULL || CFGetTypeID(hash) != CFDataGetTypeID())
 412                 MacOSError::throwMe(errSecCSResourcesInvalid);
 413         return CFDataGetBytePtr(CFDataRef(hash));
 414 }
 415
 416
 417 } // end namespace CodeSigning
 418 } // end namespace Security