DXR will be turned off on Tuesday, December 29th. It will redirect to Searchfox.
See the announcement on Discourse.

DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Mercurial (dcc6d7a0dc00)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsNSSCertificateDB.h"

#include "AppTrustDomain.h"
#include "base64.h"
#include "certdb.h"
#include "CryptoTask.h"
#include "mozilla/RefPtr.h"
#include "mozilla/UniquePtr.h"
#include "nsComponentManagerUtils.h"
#include "nsCOMPtr.h"
#include "nsDataSignatureVerifier.h"
#include "nsHashKeys.h"
#include "nsIFile.h"
#include "nsIFileStreams.h"
#include "nsIInputStream.h"
#include "nsIStringEnumerator.h"
#include "nsIDirectoryEnumerator.h"
#include "nsIZipReader.h"
#include "nsNetUtil.h"
#include "nsNSSCertificate.h"
#include "nsProxyRelease.h"
#include "nssb64.h"
#include "NSSCertDBTrustDomain.h"
#include "nsString.h"
#include "nsTHashtable.h"
#include "plstr.h"
#include "mozilla/Logging.h"
#include "pkix/pkix.h"
#include "pkix/pkixnss.h"
#include "secmime.h"


using namespace mozilla::pkix;
using namespace mozilla;
using namespace mozilla::psm;

extern PRLogModuleInfo* gPIPNSSLog;

namespace {

// Reads a maximum of 1MB from a stream into the supplied buffer.
// The reason for the 1MB limit is because this function is used to read
// signature-related files and we want to avoid OOM. The uncompressed length of
// an entry can be hundreds of times larger than the compressed version,
// especially if someone has specifically crafted the entry to cause OOM or to
// consume massive amounts of disk space.
//
// @param stream  The input stream to read from.
// @param buf     The buffer that we read the stream into, which must have
//                already been allocated.
nsresult
ReadStream(const nsCOMPtr<nsIInputStream>& stream, /*out*/ SECItem& buf)
{
  // The size returned by Available() might be inaccurate so we need
  // to check that Available() matches up with the actual length of
  // the file.
  uint64_t length;
  nsresult rv = stream->Available(&length);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  // Cap the maximum accepted size of signature-related files at 1MB (which is
  // still crazily huge) to avoid OOM. The uncompressed length of an entry can be
  // hundreds of times larger than the compressed version, especially if
  // someone has speifically crafted the entry to cause OOM or to consume
  // massive amounts of disk space.
  static const uint32_t MAX_LENGTH = 1024 * 1024;
  if (length > MAX_LENGTH) {
    return NS_ERROR_FILE_TOO_BIG;
  }

  // With bug 164695 in mind we +1 to leave room for null-terminating
  // the buffer.
  SECITEM_AllocItem(buf, static_cast<uint32_t>(length + 1));

  // buf.len == length + 1. We attempt to read length + 1 bytes
  // instead of length, so that we can check whether the metadata for
  // the entry is incorrect.
  uint32_t bytesRead;
  rv = stream->Read(char_ptr_cast(buf.data), buf.len, &bytesRead);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }
  if (bytesRead != length) {
    return NS_ERROR_FILE_CORRUPTED;
  }

  buf.data[buf.len - 1] = 0; // null-terminate

  return NS_OK;
}

// Finds exactly one (signature metadata) JAR entry that matches the given
// search pattern, and then load it. Fails if there are no matches or if
// there is more than one match. If bugDigest is not null then on success
// bufDigest will contain the SHA-1 digeset of the entry.
nsresult
FindAndLoadOneEntry(nsIZipReader * zip,
                    const nsACString & searchPattern,
                    /*out*/ nsACString & filename,
                    /*out*/ SECItem & buf,
                    /*optional, out*/ Digest * bufDigest)
{
  nsCOMPtr<nsIUTF8StringEnumerator> files;
  nsresult rv = zip->FindEntries(searchPattern, getter_AddRefs(files));
  if (NS_FAILED(rv) || !files) {
    return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
  }

  bool more;
  rv = files->HasMore(&more);
  NS_ENSURE_SUCCESS(rv, rv);
  if (!more) {
    return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
  }

  rv = files->GetNext(filename);
  NS_ENSURE_SUCCESS(rv, rv);

  // Check if there is more than one match, if so then error!
  rv = files->HasMore(&more);
  NS_ENSURE_SUCCESS(rv, rv);
  if (more) {
    return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
  }

  nsCOMPtr<nsIInputStream> stream;
  rv = zip->GetInputStream(filename, getter_AddRefs(stream));
  NS_ENSURE_SUCCESS(rv, rv);

  rv = ReadStream(stream, buf);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return NS_ERROR_SIGNED_JAR_ENTRY_INVALID;
  }

  if (bufDigest) {
    rv = bufDigest->DigestBuf(SEC_OID_SHA1, buf.data, buf.len - 1);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  return NS_OK;
}

// Verify the digest of an entry. We avoid loading the entire entry into memory
// at once, which would require memory in proportion to the size of the largest
// entry. Instead, we require only a small, fixed amount of memory.
//
// @param stream  an input stream from a JAR entry or file depending on whether
//                it is from a signed archive or unpacked into a directory
// @param digestFromManifest The digest that we're supposed to check the file's
//                           contents against, from the manifest
// @param buf A scratch buffer that we use for doing the I/O, which must have
//            already been allocated. The size of this buffer is the unit
//            size of our I/O.
nsresult
VerifyStreamContentDigest(nsIInputStream* stream,
                          const SECItem& digestFromManifest, SECItem& buf)
{
  MOZ_ASSERT(buf.len > 0);
  if (digestFromManifest.len != SHA1_LENGTH)
    return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;

  nsresult rv;
  uint64_t len64;
  rv = stream->Available(&len64);
  NS_ENSURE_SUCCESS(rv, rv);
  if (len64 > UINT32_MAX) {
    return NS_ERROR_SIGNED_JAR_ENTRY_TOO_LARGE;
  }

  ScopedPK11Context digestContext(PK11_CreateDigestContext(SEC_OID_SHA1));
  if (!digestContext) {
    return mozilla::psm::GetXPCOMFromNSSError(PR_GetError());
  }

  rv = MapSECStatus(PK11_DigestBegin(digestContext));
  NS_ENSURE_SUCCESS(rv, rv);

  uint64_t totalBytesRead = 0;
  for (;;) {
    uint32_t bytesRead;
    rv = stream->Read(char_ptr_cast(buf.data), buf.len, &bytesRead);
    NS_ENSURE_SUCCESS(rv, rv);

    if (bytesRead == 0) {
      break; // EOF
    }

    totalBytesRead += bytesRead;
    if (totalBytesRead >= UINT32_MAX) {
      return NS_ERROR_SIGNED_JAR_ENTRY_TOO_LARGE;
    }

    rv = MapSECStatus(PK11_DigestOp(digestContext, buf.data, bytesRead));
    NS_ENSURE_SUCCESS(rv, rv);
  }

  if (totalBytesRead != len64) {
    // The metadata we used for Available() doesn't match the actual size of
    // the entry.
    return NS_ERROR_SIGNED_JAR_ENTRY_INVALID;
  }

  // Verify that the digests match.
  Digest digest;
  rv = digest.End(SEC_OID_SHA1, digestContext);
  NS_ENSURE_SUCCESS(rv, rv);

  if (SECITEM_CompareItem(&digestFromManifest, &digest.get()) != SECEqual) {
    return NS_ERROR_SIGNED_JAR_MODIFIED_ENTRY;
  }

  return NS_OK;
}

nsresult
VerifyEntryContentDigest(nsIZipReader* zip, const nsACString& aFilename,
                         const SECItem& digestFromManifest, SECItem& buf)
{
  nsCOMPtr<nsIInputStream> stream;
  nsresult rv = zip->GetInputStream(aFilename, getter_AddRefs(stream));
  if (NS_FAILED(rv)) {
    return NS_ERROR_SIGNED_JAR_ENTRY_MISSING;
  }

  return VerifyStreamContentDigest(stream, digestFromManifest, buf);
}

// @oaram aDir       directory containing the unpacked signed archive
// @param aFilename  path of the target file relative to aDir
// @param digestFromManifest The digest that we're supposed to check the file's
//                           contents against, from the manifest
// @param buf A scratch buffer that we use for doing the I/O
nsresult
VerifyFileContentDigest(nsIFile* aDir, const nsAString& aFilename,
                        const SECItem& digestFromManifest, SECItem& buf)
{
  // Find the file corresponding to the manifest path
  nsCOMPtr<nsIFile> file;
  nsresult rv = aDir->Clone(getter_AddRefs(file));
  if (NS_FAILED(rv)) {
    return rv;
  }

  // We don't know how to handle JARs with signed directory entries.
  // It's technically possible in the manifest but makes no sense on disk.
  // Inside an archive we just ignore them, but here we have to treat it
  // as an error because the signed bytes never got unpacked.
  int32_t pos = 0;
  int32_t slash;
  int32_t namelen = aFilename.Length();
  if (namelen == 0 || aFilename[namelen - 1] == '/') {
    return NS_ERROR_SIGNED_JAR_ENTRY_INVALID;
  }

  // Append path segments one by one
  do {
    slash = aFilename.FindChar('/', pos);
    int32_t segend = (slash == kNotFound) ? namelen : slash;
    rv = file->Append(Substring(aFilename, pos, (segend - pos)));
    if (NS_FAILED(rv)) {
      return NS_ERROR_SIGNED_JAR_ENTRY_INVALID;
    }
    pos = slash + 1;
  }  while (pos < namelen && slash != kNotFound);

  bool exists;
  rv = file->Exists(&exists);
  if (NS_FAILED(rv) || !exists) {
    return NS_ERROR_SIGNED_JAR_ENTRY_MISSING;
  }

  bool isDir;
  rv = file->IsDirectory(&isDir);
  if (NS_FAILED(rv) || isDir) {
    // We only support signed files, not directory entries
    return NS_ERROR_SIGNED_JAR_ENTRY_INVALID;
  }

  // Open an input stream for that file and verify it.
  nsCOMPtr<nsIInputStream> stream;
  rv = NS_NewLocalFileInputStream(getter_AddRefs(stream), file, -1, -1,
                                  nsIFileInputStream::CLOSE_ON_EOF);
  if (NS_FAILED(rv) || !stream) {
    return NS_ERROR_SIGNED_JAR_ENTRY_MISSING;
  }

  return VerifyStreamContentDigest(stream, digestFromManifest, buf);
}

// On input, nextLineStart is the start of the current line. On output,
// nextLineStart is the start of the next line.
nsresult
ReadLine(/*in/out*/ const char* & nextLineStart, /*out*/ nsCString & line,
         bool allowContinuations = true)
{
  line.Truncate();
  size_t previousLength = 0;
  size_t currentLength = 0;
  for (;;) {
    const char* eol = PL_strpbrk(nextLineStart, "\r\n");

    if (!eol) { // Reached end of file before newline
      eol = nextLineStart + strlen(nextLineStart);
    }

    previousLength = currentLength;
    line.Append(nextLineStart, eol - nextLineStart);
    currentLength = line.Length();

    // The spec says "No line may be longer than 72 bytes (not characters)"
    // in its UTF8-encoded form.
    static const size_t lineLimit = 72;
    if (currentLength - previousLength > lineLimit) {
      return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
    }

    // The spec says: "Implementations should support 65535-byte
    // (not character) header values..."
    if (currentLength > 65535) {
      return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
    }

    if (*eol == '\r') {
      ++eol;
    }
    if (*eol == '\n') {
      ++eol;
    }

    nextLineStart = eol;

    if (*eol != ' ') {
      // not a continuation
      return NS_OK;
    }

    // continuation
    if (!allowContinuations) {
      return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
    }

    ++nextLineStart; // skip space and keep appending
  }
}

// The header strings are defined in the JAR specification.
#define JAR_MF_SEARCH_STRING "(M|/M)ETA-INF/(M|m)(ANIFEST|anifest).(MF|mf)$"
#define JAR_SF_SEARCH_STRING "(M|/M)ETA-INF/*.(SF|sf)$"
#define JAR_RSA_SEARCH_STRING "(M|/M)ETA-INF/*.(RSA|rsa)$"
#define JAR_META_DIR "META-INF"
#define JAR_MF_HEADER "Manifest-Version: 1.0"
#define JAR_SF_HEADER "Signature-Version: 1.0"

nsresult
ParseAttribute(const nsAutoCString & curLine,
               /*out*/ nsAutoCString & attrName,
               /*out*/ nsAutoCString & attrValue)
{
  // Find the colon that separates the name from the value.
  int32_t colonPos = curLine.FindChar(':');
  if (colonPos == kNotFound) {
    return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
  }

  // set attrName to the name, skipping spaces between the name and colon
  int32_t nameEnd = colonPos;
  for (;;) {
    if (nameEnd == 0) {
      return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID; // colon with no name
    }
    if (curLine[nameEnd - 1] != ' ')
      break;
    --nameEnd;
  }
  curLine.Left(attrName, nameEnd);

  // Set attrValue to the value, skipping spaces between the colon and the
  // value. The value may be empty.
  int32_t valueStart = colonPos + 1;
  int32_t curLineLength = curLine.Length();
  while (valueStart != curLineLength && curLine[valueStart] == ' ') {
    ++valueStart;
  }
  curLine.Right(attrValue, curLineLength - valueStart);

  return NS_OK;
}

// Parses the version line of the MF or SF header.
nsresult
CheckManifestVersion(const char* & nextLineStart,
                     const nsACString & expectedHeader)
{
  // The JAR spec says: "Manifest-Version and Signature-Version must be first,
  // and in exactly that case (so that they can be recognized easily as magic
  // strings)."
  nsAutoCString curLine;
  nsresult rv = ReadLine(nextLineStart, curLine, false);
  if (NS_FAILED(rv)) {
    return rv;
  }
  if (!curLine.Equals(expectedHeader)) {
    return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
  }
  return NS_OK;
}

// Parses a signature file (SF) as defined in the JDK 8 JAR Specification.
//
// The SF file *must* contain exactly one SHA1-Digest-Manifest attribute in
// the main section. All other sections are ignored. This means that this will
// NOT parse old-style signature files that have separate digests per entry.
// The JDK8 x-Digest-Manifest variant is better because:
//
//   (1) It allows us to follow the principle that we should minimize the
//       processing of data that we do before we verify its signature. In
//       particular, with the x-Digest-Manifest style, we can verify the digest
//       of MANIFEST.MF before we parse it, which prevents malicious JARs
//       exploiting our MANIFEST.MF parser.
//   (2) It is more time-efficient and space-efficient to have one
//       x-Digest-Manifest instead of multiple x-Digest values.
//
// In order to get benefit (1), we do NOT implement the fallback to the older
// mechanism as the spec requires/suggests. Also, for simplity's sake, we only
// support exactly one SHA1-Digest-Manifest attribute, and no other
// algorithms.
//
// filebuf must be null-terminated. On output, mfDigest will contain the
// decoded value of SHA1-Digest-Manifest.
nsresult
ParseSF(const char* filebuf, /*out*/ SECItem & mfDigest)
{
  nsresult rv;

  const char* nextLineStart = filebuf;
  rv = CheckManifestVersion(nextLineStart, NS_LITERAL_CSTRING(JAR_SF_HEADER));
  if (NS_FAILED(rv))
    return rv;

  // Find SHA1-Digest-Manifest
  for (;;) {
    nsAutoCString curLine;
    rv = ReadLine(nextLineStart, curLine);
    if (NS_FAILED(rv)) {
      return rv;
    }

    if (curLine.Length() == 0) {
      // End of main section (blank line or end-of-file), and no
      // SHA1-Digest-Manifest found.
      return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
    }

    nsAutoCString attrName;
    nsAutoCString attrValue;
    rv = ParseAttribute(curLine, attrName, attrValue);
    if (NS_FAILED(rv)) {
      return rv;
    }

    if (attrName.LowerCaseEqualsLiteral("sha1-digest-manifest")) {
      rv = MapSECStatus(ATOB_ConvertAsciiToItem(&mfDigest, attrValue.get()));
      if (NS_FAILED(rv)) {
        return rv;
      }

      // There could be multiple SHA1-Digest-Manifest attributes, which
      // would be an error, but it's better to just skip any erroneous
      // duplicate entries rather than trying to detect them, because:
      //
      //   (1) It's simpler, and simpler generally means more secure
      //   (2) An attacker can't make us accept a JAR we would otherwise
      //       reject just by adding additional SHA1-Digest-Manifest
      //       attributes.
      break;
    }

    // ignore unrecognized attributes
  }

  return NS_OK;
}

// Parses MANIFEST.MF. The filenames of all entries will be returned in
// mfItems. buf must be a pre-allocated scratch buffer that is used for doing
// I/O.
nsresult
ParseMF(const char* filebuf, nsIZipReader * zip,
        /*out*/ nsTHashtable<nsCStringHashKey> & mfItems,
        ScopedAutoSECItem & buf)
{
  nsresult rv;

  const char* nextLineStart = filebuf;

  rv = CheckManifestVersion(nextLineStart, NS_LITERAL_CSTRING(JAR_MF_HEADER));
  if (NS_FAILED(rv)) {
    return rv;
  }

  // Skip the rest of the header section, which ends with a blank line.
  {
    nsAutoCString line;
    do {
      rv = ReadLine(nextLineStart, line);
      if (NS_FAILED(rv)) {
        return rv;
      }
    } while (line.Length() > 0);

    // Manifest containing no file entries is OK, though useless.
    if (*nextLineStart == '\0') {
      return NS_OK;
    }
  }

  nsAutoCString curItemName;
  ScopedAutoSECItem digest;

  for (;;) {
    nsAutoCString curLine;
    rv = ReadLine(nextLineStart, curLine);
    NS_ENSURE_SUCCESS(rv, rv);

    if (curLine.Length() == 0) {
      // end of section (blank line or end-of-file)

      if (curItemName.Length() == 0) {
        // '...Each section must start with an attribute with the name as
        // "Name",...', so every section must have a Name attribute.
        return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
      }

      if (digest.len == 0) {
        // We require every entry to have a digest, since we require every
        // entry to be signed and we don't allow duplicate entries.
        return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
      }

      if (mfItems.Contains(curItemName)) {
        // Duplicate entry
        return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
      }

      // Verify that the entry's content digest matches the digest from this
      // MF section.
      rv = VerifyEntryContentDigest(zip, curItemName, digest, buf);
      if (NS_FAILED(rv))
        return rv;

      mfItems.PutEntry(curItemName);

      if (*nextLineStart == '\0') // end-of-file
        break;

      // reset so we know we haven't encountered either of these for the next
      // item yet.
      curItemName.Truncate();
      digest.reset();

      continue; // skip the rest of the loop below
    }

    nsAutoCString attrName;
    nsAutoCString attrValue;
    rv = ParseAttribute(curLine, attrName, attrValue);
    if (NS_FAILED(rv)) {
      return rv;
    }

    // Lines to look for:

    // (1) Digest:
    if (attrName.LowerCaseEqualsLiteral("sha1-digest"))
    {
      if (digest.len > 0) // multiple SHA1 digests in section
        return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;

      rv = MapSECStatus(ATOB_ConvertAsciiToItem(&digest, attrValue.get()));
      if (NS_FAILED(rv))
        return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;

      continue;
    }

    // (2) Name: associates this manifest section with a file in the jar.
    if (attrName.LowerCaseEqualsLiteral("name"))
    {
      if (MOZ_UNLIKELY(curItemName.Length() > 0)) // multiple names in section
        return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;

      if (MOZ_UNLIKELY(attrValue.Length() == 0))
        return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;

      curItemName = attrValue;

      continue;
    }

    // (3) Magic: the only other must-understand attribute
    if (attrName.LowerCaseEqualsLiteral("magic")) {
      // We don't understand any magic, so we can't verify an entry that
      // requires magic. Since we require every entry to have a valid
      // signature, we have no choice but to reject the entry.
      return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
    }

    // unrecognized attributes must be ignored
  }

  return NS_OK;
}

struct VerifyCertificateContext {
  AppTrustedRoot trustedRoot;
  ScopedCERTCertList& builtChain;
};

nsresult
VerifyCertificate(CERTCertificate* signerCert, void* voidContext, void* pinArg)
{
  // TODO: null pinArg is tolerated.
  if (NS_WARN_IF(!signerCert) || NS_WARN_IF(!voidContext)) {
    return NS_ERROR_INVALID_ARG;
  }
  const VerifyCertificateContext& context =
    *reinterpret_cast<const VerifyCertificateContext*>(voidContext);

  AppTrustDomain trustDomain(context.builtChain, pinArg);
  if (trustDomain.SetTrustedRoot(context.trustedRoot) != SECSuccess) {
    return MapSECStatus(SECFailure);
  }
  Input certDER;
  Result rv = certDER.Init(signerCert->derCert.data, signerCert->derCert.len);
  if (rv != Success) {
    return mozilla::psm::GetXPCOMFromNSSError(MapResultToPRErrorCode(rv));
  }

  rv = BuildCertChain(trustDomain, certDER, Now(),
                      EndEntityOrCA::MustBeEndEntity,
                      KeyUsage::digitalSignature,
                      KeyPurposeId::id_kp_codeSigning,
                      CertPolicyId::anyPolicy,
                      nullptr/*stapledOCSPResponse*/);
  if (rv == Result::ERROR_EXPIRED_CERTIFICATE) {
    // For code-signing you normally need trusted 3rd-party timestamps to
    // handle expiration properly. The signer could always mess with their
    // system clock so you can't trust the certificate was un-expired when
    // the signing took place. The choice is either to ignore expiration
    // or to enforce expiration at time of use. The latter leads to the
    // user-hostile result that perfectly good code stops working.
    //
    // Our package format doesn't support timestamps (nor do we have a
    // trusted 3rd party timestamper), but since we sign all of our apps and
    // add-ons ourselves we can trust ourselves not to mess with the clock
    // on the signing systems. We also have a revocation mechanism if we
    // need it. It's OK to ignore cert expiration under these conditions.
    //
    // This is an invalid approach if
    //  * we issue certs to let others sign their own packages
    //  * mozilla::pkix returns "expired" when there are "worse" problems
    //    with the certificate or chain.
    // (see bug 1267318)
    rv = Success;
  }
  if (rv != Success) {
    return mozilla::psm::GetXPCOMFromNSSError(MapResultToPRErrorCode(rv));
  }

  return NS_OK;
}

nsresult
VerifySignature(AppTrustedRoot trustedRoot, const SECItem& buffer,
                const SECItem& detachedDigest,
                /*out*/ ScopedCERTCertList& builtChain)
{
  VerifyCertificateContext context = { trustedRoot, builtChain };
  // XXX: missing pinArg
  return VerifyCMSDetachedSignatureIncludingCertificate(buffer, detachedDigest,
                                                        VerifyCertificate,
                                                        &context, nullptr);
}

NS_IMETHODIMP
OpenSignedAppFile(AppTrustedRoot aTrustedRoot, nsIFile* aJarFile,
                  /*out, optional */ nsIZipReader** aZipReader,
                  /*out, optional */ nsIX509Cert** aSignerCert)
{
  NS_ENSURE_ARG_POINTER(aJarFile);

  if (aZipReader) {
    *aZipReader = nullptr;
  }

  if (aSignerCert) {
    *aSignerCert = nullptr;
  }

  nsresult rv;

  static NS_DEFINE_CID(kZipReaderCID, NS_ZIPREADER_CID);
  nsCOMPtr<nsIZipReader> zip = do_CreateInstance(kZipReaderCID, &rv);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = zip->Open(aJarFile);
  NS_ENSURE_SUCCESS(rv, rv);

  // Signature (RSA) file
  nsAutoCString sigFilename;
  ScopedAutoSECItem sigBuffer;
  rv = FindAndLoadOneEntry(zip, nsLiteralCString(JAR_RSA_SEARCH_STRING),
                           sigFilename, sigBuffer, nullptr);
  if (NS_FAILED(rv)) {
    return NS_ERROR_SIGNED_JAR_NOT_SIGNED;
  }

  // Signature (SF) file
  nsAutoCString sfFilename;
  ScopedAutoSECItem sfBuffer;
  Digest sfCalculatedDigest;
  rv = FindAndLoadOneEntry(zip, NS_LITERAL_CSTRING(JAR_SF_SEARCH_STRING),
                           sfFilename, sfBuffer, &sfCalculatedDigest);
  if (NS_FAILED(rv)) {
    return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
  }

  sigBuffer.type = siBuffer;
  ScopedCERTCertList builtChain;
  rv = VerifySignature(aTrustedRoot, sigBuffer, sfCalculatedDigest.get(),
                       builtChain);
  if (NS_FAILED(rv)) {
    return rv;
  }

  ScopedAutoSECItem mfDigest;
  rv = ParseSF(char_ptr_cast(sfBuffer.data), mfDigest);
  if (NS_FAILED(rv)) {
    return rv;
  }

  // Manifest (MF) file
  nsAutoCString mfFilename;
  ScopedAutoSECItem manifestBuffer;
  Digest mfCalculatedDigest;
  rv = FindAndLoadOneEntry(zip, NS_LITERAL_CSTRING(JAR_MF_SEARCH_STRING),
                           mfFilename, manifestBuffer, &mfCalculatedDigest);
  if (NS_FAILED(rv)) {
    return rv;
  }

  if (SECITEM_CompareItem(&mfDigest, &mfCalculatedDigest.get()) != SECEqual) {
    return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
  }

  // Allocate the I/O buffer only once per JAR, instead of once per entry, in
  // order to minimize malloc/free calls and in order to avoid fragmenting
  // memory.
  ScopedAutoSECItem buf(128 * 1024);

  nsTHashtable<nsCStringHashKey> items;

  rv = ParseMF(char_ptr_cast(manifestBuffer.data), zip, items, buf);
  if (NS_FAILED(rv)) {
    return rv;
  }

  // Verify every entry in the file.
  nsCOMPtr<nsIUTF8StringEnumerator> entries;
  rv = zip->FindEntries(EmptyCString(), getter_AddRefs(entries));
  if (NS_SUCCEEDED(rv) && !entries) {
    rv = NS_ERROR_UNEXPECTED;
  }
  if (NS_FAILED(rv)) {
    return rv;
  }

  for (;;) {
    bool hasMore;
    rv = entries->HasMore(&hasMore);
    NS_ENSURE_SUCCESS(rv, rv);

    if (!hasMore) {
      break;
    }

    nsAutoCString entryFilename;
    rv = entries->GetNext(entryFilename);
    NS_ENSURE_SUCCESS(rv, rv);

    MOZ_LOG(gPIPNSSLog, LogLevel::Debug, ("Verifying digests for %s",
           entryFilename.get()));

    // The files that comprise the signature mechanism are not covered by the
    // signature.
    //
    // XXX: This is OK for a single signature, but doesn't work for
    // multiple signatures, because the metadata for the other signatures
    // is not signed either.
    if (entryFilename == mfFilename ||
        entryFilename == sfFilename ||
        entryFilename == sigFilename) {
      continue;
    }

    if (entryFilename.Length() == 0) {
      return NS_ERROR_SIGNED_JAR_ENTRY_INVALID;
    }

    // Entries with names that end in "/" are directory entries, which are not
    // signed.
    //
    // XXX: As long as we don't unpack the JAR into the filesystem, the "/"
    // entries are harmless. But, it is not clear what the security
    // implications of directory entries are if/when we were to unpackage the
    // JAR into the filesystem.
    if (entryFilename[entryFilename.Length() - 1] == '/') {
      continue;
    }

    nsCStringHashKey * item = items.GetEntry(entryFilename);
    if (!item) {
      return NS_ERROR_SIGNED_JAR_UNSIGNED_ENTRY;
    }

    // Remove the item so we can check for leftover items later
    items.RemoveEntry(item);
  }

  // We verified that every entry that we require to be signed is signed. But,
  // were there any missing entries--that is, entries that are mentioned in the
  // manifest but missing from the archive?
  if (items.Count() != 0) {
    return NS_ERROR_SIGNED_JAR_ENTRY_MISSING;
  }

  // Return the reader to the caller if they want it
  if (aZipReader) {
    zip.forget(aZipReader);
  }

  // Return the signer's certificate to the reader if they want it.
  // XXX: We should return an nsIX509CertList with the whole validated chain.
  if (aSignerCert) {
    MOZ_ASSERT(CERT_LIST_HEAD(builtChain));
    nsCOMPtr<nsIX509Cert> signerCert =
      nsNSSCertificate::Create(CERT_LIST_HEAD(builtChain)->cert);
    NS_ENSURE_TRUE(signerCert, NS_ERROR_OUT_OF_MEMORY);
    signerCert.forget(aSignerCert);
  }

  return NS_OK;
}

nsresult
VerifySignedManifest(AppTrustedRoot aTrustedRoot,
                     nsIInputStream* aManifestStream,
                     nsIInputStream* aSignatureStream,
                     /*out, optional */ nsIX509Cert** aSignerCert)
{
  NS_ENSURE_ARG(aManifestStream);
  NS_ENSURE_ARG(aSignatureStream);

  if (aSignerCert) {
    *aSignerCert = nullptr;
  }

  // Load signature file in buffer
  ScopedAutoSECItem signatureBuffer;
  nsresult rv = ReadStream(aSignatureStream, signatureBuffer);
  if (NS_FAILED(rv)) {
    return rv;
  }
  signatureBuffer.type = siBuffer;

  // Load manifest file in buffer
  ScopedAutoSECItem manifestBuffer;
  rv = ReadStream(aManifestStream, manifestBuffer);
  if (NS_FAILED(rv)) {
    return rv;
  }

  // Calculate SHA1 digest of the manifest buffer
  Digest manifestCalculatedDigest;
  rv = manifestCalculatedDigest.DigestBuf(SEC_OID_SHA1,
                                          manifestBuffer.data,
                                          manifestBuffer.len - 1); // buffer is null terminated
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  // Get base64 encoded string from manifest buffer digest
  UniquePtr<char, void(&)(void*)>
    base64EncDigest(NSSBase64_EncodeItem(nullptr, nullptr, 0,
                      const_cast<SECItem*>(&manifestCalculatedDigest.get())),
                    PORT_Free);
  if (NS_WARN_IF(!base64EncDigest)) {
    return NS_ERROR_OUT_OF_MEMORY;
  }

  // Calculate SHA1 digest of the base64 encoded string
  Digest doubleDigest;
  rv = doubleDigest.DigestBuf(SEC_OID_SHA1,
                              reinterpret_cast<uint8_t*>(base64EncDigest.get()),
                              strlen(base64EncDigest.get()));
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  // Verify the manifest signature (signed digest of the base64 encoded string)
  ScopedCERTCertList builtChain;
  rv = VerifySignature(aTrustedRoot, signatureBuffer,
                       doubleDigest.get(), builtChain);
  if (NS_FAILED(rv)) {
    return rv;
  }

  // Return the signer's certificate to the reader if they want it.
  if (aSignerCert) {
    MOZ_ASSERT(CERT_LIST_HEAD(builtChain));
    nsCOMPtr<nsIX509Cert> signerCert =
      nsNSSCertificate::Create(CERT_LIST_HEAD(builtChain)->cert);
    if (NS_WARN_IF(!signerCert)) {
      return NS_ERROR_OUT_OF_MEMORY;
    }

    signerCert.forget(aSignerCert);
  }

  return NS_OK;
}

class OpenSignedAppFileTask final : public CryptoTask
{
public:
  OpenSignedAppFileTask(AppTrustedRoot aTrustedRoot, nsIFile* aJarFile,
                        nsIOpenSignedAppFileCallback* aCallback)
    : mTrustedRoot(aTrustedRoot)
    , mJarFile(aJarFile)
    , mCallback(new nsMainThreadPtrHolder<nsIOpenSignedAppFileCallback>(aCallback))
  {
  }

private:
  virtual nsresult CalculateResult() override
  {
    return OpenSignedAppFile(mTrustedRoot, mJarFile,
                             getter_AddRefs(mZipReader),
                             getter_AddRefs(mSignerCert));
  }

  // nsNSSCertificate implements nsNSSShutdownObject, so there's nothing that
  // needs to be released
  virtual void ReleaseNSSResources() override { }

  virtual void CallCallback(nsresult rv) override
  {
    (void) mCallback->OpenSignedAppFileFinished(rv, mZipReader, mSignerCert);
  }

  const AppTrustedRoot mTrustedRoot;
  const nsCOMPtr<nsIFile> mJarFile;
  nsMainThreadPtrHandle<nsIOpenSignedAppFileCallback> mCallback;
  nsCOMPtr<nsIZipReader> mZipReader; // out
  nsCOMPtr<nsIX509Cert> mSignerCert; // out
};

class VerifySignedmanifestTask final : public CryptoTask
{
public:
  VerifySignedmanifestTask(AppTrustedRoot aTrustedRoot,
                           nsIInputStream* aManifestStream,
                           nsIInputStream* aSignatureStream,
                           nsIVerifySignedManifestCallback* aCallback)
    : mTrustedRoot(aTrustedRoot)
    , mManifestStream(aManifestStream)
    , mSignatureStream(aSignatureStream)
    , mCallback(
      new nsMainThreadPtrHolder<nsIVerifySignedManifestCallback>(aCallback))
  {
  }

private:
  virtual nsresult CalculateResult() override
  {
    return VerifySignedManifest(mTrustedRoot, mManifestStream,
                                mSignatureStream, getter_AddRefs(mSignerCert));
  }

  // nsNSSCertificate implements nsNSSShutdownObject, so there's nothing that
  // needs to be released
  virtual void ReleaseNSSResources() override { }

  virtual void CallCallback(nsresult rv) override
  {
    (void) mCallback->VerifySignedManifestFinished(rv, mSignerCert);
  }

  const AppTrustedRoot mTrustedRoot;
  const nsCOMPtr<nsIInputStream> mManifestStream;
  const nsCOMPtr<nsIInputStream> mSignatureStream;
  nsMainThreadPtrHandle<nsIVerifySignedManifestCallback> mCallback;
  nsCOMPtr<nsIX509Cert> mSignerCert; // out
};

} // unnamed namespace

NS_IMETHODIMP
nsNSSCertificateDB::OpenSignedAppFileAsync(
  AppTrustedRoot aTrustedRoot, nsIFile* aJarFile,
  nsIOpenSignedAppFileCallback* aCallback)
{
  NS_ENSURE_ARG_POINTER(aJarFile);
  NS_ENSURE_ARG_POINTER(aCallback);
  RefPtr<OpenSignedAppFileTask> task(new OpenSignedAppFileTask(aTrustedRoot,
                                                               aJarFile,
                                                               aCallback));
  return task->Dispatch("SignedJAR");
}

NS_IMETHODIMP
nsNSSCertificateDB::VerifySignedManifestAsync(
  AppTrustedRoot aTrustedRoot, nsIInputStream* aManifestStream,
  nsIInputStream* aSignatureStream, nsIVerifySignedManifestCallback* aCallback)
{
  NS_ENSURE_ARG_POINTER(aManifestStream);
  NS_ENSURE_ARG_POINTER(aSignatureStream);
  NS_ENSURE_ARG_POINTER(aCallback);

  RefPtr<VerifySignedmanifestTask> task(
    new VerifySignedmanifestTask(aTrustedRoot, aManifestStream,
                                 aSignatureStream, aCallback));
  return task->Dispatch("SignedManifest");
}


//
// Signature verification for archives unpacked into a file structure
//

// Finds the "*.rsa" signature file in the META-INF directory and returns
// the name. It is an error if there are none or more than one .rsa file
nsresult
FindSignatureFilename(nsIFile* aMetaDir,
                      /*out*/ nsAString& aFilename)
{
  nsCOMPtr<nsISimpleEnumerator> entries;
  nsresult rv = aMetaDir->GetDirectoryEntries(getter_AddRefs(entries));
  nsCOMPtr<nsIDirectoryEnumerator> files = do_QueryInterface(entries);
  if (NS_FAILED(rv) || !files) {
    return NS_ERROR_SIGNED_JAR_NOT_SIGNED;
  }

  bool found = false;
  nsCOMPtr<nsIFile> file;
  rv = files->GetNextFile(getter_AddRefs(file));

  while (NS_SUCCEEDED(rv) && file) {
    nsAutoString leafname;
    rv = file->GetLeafName(leafname);
    if (NS_SUCCEEDED(rv)) {
      if (StringEndsWith(leafname, NS_LITERAL_STRING(".rsa"))) {
        if (!found) {
          found = true;
          aFilename = leafname;
        } else {
          // second signature file is an error
          rv = NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
          break;
        }
      }
      rv = files->GetNextFile(getter_AddRefs(file));
    }
  }

  if (!found) {
    rv = NS_ERROR_SIGNED_JAR_NOT_SIGNED;
  }

  files->Close();
  return rv;
}

// Loads the signature metadata file that matches the given filename in
// the passed-in Meta-inf directory. If bufDigest is not null then on
// success bufDigest will contain the SHA-1 digest of the entry.
nsresult
LoadOneMetafile(nsIFile* aMetaDir,
                const nsAString& aFilename,
                /*out*/ SECItem& aBuf,
                /*optional, out*/ Digest* aBufDigest)
{
  nsCOMPtr<nsIFile> metafile;
  nsresult rv = aMetaDir->Clone(getter_AddRefs(metafile));
  NS_ENSURE_SUCCESS(rv, rv);

  rv = metafile->Append(aFilename);
  NS_ENSURE_SUCCESS(rv, rv);

  bool exists;
  rv = metafile->Exists(&exists);
  if (NS_FAILED(rv) || !exists) {
    // we can call a missing .rsa file "unsigned" but FindSignatureFilename()
    // already found one: missing other metadata files means a broken signature.
    return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
  }

  nsCOMPtr<nsIInputStream> stream;
  rv = NS_NewLocalFileInputStream(getter_AddRefs(stream), metafile);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = ReadStream(stream, aBuf);
  stream->Close();
  NS_ENSURE_SUCCESS(rv, rv);

  if (aBufDigest) {
    rv = aBufDigest->DigestBuf(SEC_OID_SHA1, aBuf.data, aBuf.len - 1);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  return NS_OK;
}

// Parses MANIFEST.MF and verifies the contents of the unpacked files
// listed in the manifest.
// The filenames of all entries will be returned in aMfItems. aBuf must
// be a pre-allocated scratch buffer that is used for doing I/O.
nsresult
ParseMFUnpacked(const char* aFilebuf, nsIFile* aDir,
                /*out*/ nsTHashtable<nsStringHashKey>& aMfItems,
                ScopedAutoSECItem& aBuf)
{
  nsresult rv;

  const char* nextLineStart = aFilebuf;

  rv = CheckManifestVersion(nextLineStart, NS_LITERAL_CSTRING(JAR_MF_HEADER));
  if (NS_FAILED(rv)) {
    return rv;
  }

  // Skip the rest of the header section, which ends with a blank line.
  {
    nsAutoCString line;
    do {
      rv = ReadLine(nextLineStart, line);
      if (NS_FAILED(rv)) {
        return rv;
      }
    } while (line.Length() > 0);

    // Manifest containing no file entries is OK, though useless.
    if (*nextLineStart == '\0') {
      return NS_OK;
    }
  }

  nsAutoString curItemName;
  ScopedAutoSECItem digest;

  for (;;) {
    nsAutoCString curLine;
    rv = ReadLine(nextLineStart, curLine);
    if (NS_FAILED(rv)) {
      return rv;
    }

    if (curLine.Length() == 0) {
      // end of section (blank line or end-of-file)

      if (curItemName.Length() == 0) {
        // '...Each section must start with an attribute with the name as
        // "Name",...', so every section must have a Name attribute.
        return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
      }

      if (digest.len == 0) {
        // We require every entry to have a digest, since we require every
        // entry to be signed and we don't allow duplicate entries.
        return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
      }

      if (aMfItems.Contains(curItemName)) {
        // Duplicate entry
        return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
      }

      // Verify that the file's content digest matches the digest from this
      // MF section.
      rv = VerifyFileContentDigest(aDir, curItemName, digest, aBuf);
      if (NS_FAILED(rv)) {
        return rv;
      }

      aMfItems.PutEntry(curItemName);

      if (*nextLineStart == '\0') {
        // end-of-file
        break;
      }

      // reset so we know we haven't encountered either of these for the next
      // item yet.
      curItemName.Truncate();
      digest.reset();

      continue; // skip the rest of the loop below
    }

    nsAutoCString attrName;
    nsAutoCString attrValue;
    rv = ParseAttribute(curLine, attrName, attrValue);
    if (NS_FAILED(rv)) {
      return rv;
    }

    // Lines to look for:

    // (1) Digest:
    if (attrName.LowerCaseEqualsLiteral("sha1-digest")) {
      if (digest.len > 0) {
        // multiple SHA1 digests in section
        return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
      }

      rv = MapSECStatus(ATOB_ConvertAsciiToItem(&digest, attrValue.get()));
      if (NS_FAILED(rv)) {
        return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
      }

      continue;
    }

    // (2) Name: associates this manifest section with a file in the jar.
    if (attrName.LowerCaseEqualsLiteral("name")) {
      if (MOZ_UNLIKELY(curItemName.Length() > 0)) {
        // multiple names in section
        return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
      }

      if (MOZ_UNLIKELY(attrValue.Length() == 0)) {
        return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
      }

      curItemName = NS_ConvertUTF8toUTF16(attrValue);

      continue;
    }

    // (3) Magic: the only other must-understand attribute
    if (attrName.LowerCaseEqualsLiteral("magic")) {
      // We don't understand any magic, so we can't verify an entry that
      // requires magic. Since we require every entry to have a valid
      // signature, we have no choice but to reject the entry.
      return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
    }

    // unrecognized attributes must be ignored
  }

  return NS_OK;
}

// recursively check a directory tree for files not in the list of
// verified files we found in the manifest. For each file we find
// Check it against the files found in the manifest. If the file wasn't
// in the manifest then it's unsigned and we can stop looking. Otherwise
// remove it from the collection so we can check leftovers later.
//
// @param aDir   Directory to check
// @param aPath  Relative path to that directory (to check against aItems)
// @param aItems All the files found
// @param *Filename  signature files that won't be in the manifest
nsresult
CheckDirForUnsignedFiles(nsIFile* aDir,
                         const nsString& aPath,
                         /* in/out */ nsTHashtable<nsStringHashKey>& aItems,
                         const nsAString& sigFilename,
                         const nsAString& sfFilename,
                         const nsAString& mfFilename)
{
  nsCOMPtr<nsISimpleEnumerator> entries;
  nsresult rv = aDir->GetDirectoryEntries(getter_AddRefs(entries));
  nsCOMPtr<nsIDirectoryEnumerator> files = do_QueryInterface(entries);
  if (NS_FAILED(rv) || !files) {
    return NS_ERROR_SIGNED_JAR_ENTRY_MISSING;
  }

  bool inMeta = StringBeginsWith(aPath, NS_LITERAL_STRING(JAR_META_DIR));

  while (NS_SUCCEEDED(rv)) {
    nsCOMPtr<nsIFile> file;
    rv = files->GetNextFile(getter_AddRefs(file));
    if (NS_FAILED(rv) || !file) {
      break;
    }

    nsAutoString leafname;
    rv = file->GetLeafName(leafname);
    if (NS_FAILED(rv)) {
      return rv;
    }

    nsAutoString curName(aPath + leafname);

    bool isDir;
    rv = file->IsDirectory(&isDir);
    if (NS_FAILED(rv)) {
      return rv;
    }

    // if it's a directory we need to recurse
    if (isDir) {
      curName.Append(NS_LITERAL_STRING("/"));
      rv = CheckDirForUnsignedFiles(file, curName, aItems,
                                    sigFilename, sfFilename, mfFilename);
    } else {
      // The files that comprise the signature mechanism are not covered by the
      // signature.
      //
      // XXX: This is OK for a single signature, but doesn't work for
      // multiple signatures because the metadata for the other signatures
      // is not signed either.
      if (inMeta && ( leafname == sigFilename ||
                      leafname == sfFilename ||
                      leafname == mfFilename )) {
        continue;
      }

      // make sure the current file was found in the manifest
      nsStringHashKey* item = aItems.GetEntry(curName);
      if (!item) {
        return NS_ERROR_SIGNED_JAR_UNSIGNED_ENTRY;
      }

      // Remove the item so we can check for leftover items later
      aItems.RemoveEntry(item);
    }
  }
  files->Close();
  return rv;
}

/*
 * Verify the signature of a directory structure as if it were a
 * signed JAR file (used for unpacked JARs)
 */
nsresult
VerifySignedDirectory(AppTrustedRoot aTrustedRoot,
                      nsIFile* aDirectory,
                      /*out, optional */ nsIX509Cert** aSignerCert)
{
  NS_ENSURE_ARG_POINTER(aDirectory);

  if (aSignerCert) {
    *aSignerCert = nullptr;
  }

  // Make sure there's a META-INF directory

  nsCOMPtr<nsIFile> metaDir;
  nsresult rv = aDirectory->Clone(getter_AddRefs(metaDir));
  if (NS_FAILED(rv)) {
    return rv;
  }
  rv = metaDir->Append(NS_LITERAL_STRING(JAR_META_DIR));
  if (NS_FAILED(rv)) {
    return rv;
  }

  bool exists;
  rv = metaDir->Exists(&exists);
  if (NS_FAILED(rv) || !exists) {
    return NS_ERROR_SIGNED_JAR_NOT_SIGNED;
  }
  bool isDirectory;
  rv = metaDir->IsDirectory(&isDirectory);
  if (NS_FAILED(rv) || !isDirectory) {
    return NS_ERROR_SIGNED_JAR_NOT_SIGNED;
  }

  // Find and load the Signature (RSA) file

  nsAutoString sigFilename;
  rv = FindSignatureFilename(metaDir, sigFilename);
  if (NS_FAILED(rv)) {
    return rv;
  }

  ScopedAutoSECItem sigBuffer;
  rv = LoadOneMetafile(metaDir, sigFilename, sigBuffer, nullptr);
  if (NS_FAILED(rv)) {
    return NS_ERROR_SIGNED_JAR_NOT_SIGNED;
  }

  // Load the signature (SF) file and verify the signature.
  // The .sf and .rsa files must have the same name apart from the extension.

  nsAutoString sfFilename(Substring(sigFilename, 0, sigFilename.Length() - 3)
                          + NS_LITERAL_STRING("sf"));

  ScopedAutoSECItem sfBuffer;
  Digest sfCalculatedDigest;
  rv = LoadOneMetafile(metaDir, sfFilename, sfBuffer, &sfCalculatedDigest);
  if (NS_FAILED(rv)) {
    return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
  }

  sigBuffer.type = siBuffer;
  ScopedCERTCertList builtChain;
  rv = VerifySignature(aTrustedRoot, sigBuffer, sfCalculatedDigest.get(),
                       builtChain);
  if (NS_FAILED(rv)) {
    return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
  }

  // Get the expected manifest hash from the signed .sf file

  ScopedAutoSECItem mfDigest;
  rv = ParseSF(char_ptr_cast(sfBuffer.data), mfDigest);
  if (NS_FAILED(rv)) {
    return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
  }

  // Load manifest (MF) file and verify signature

  nsAutoString mfFilename(NS_LITERAL_STRING("manifest.mf"));
  ScopedAutoSECItem manifestBuffer;
  Digest mfCalculatedDigest;
  rv = LoadOneMetafile(metaDir, mfFilename, manifestBuffer, &mfCalculatedDigest);
  if (NS_FAILED(rv)) {
    return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
  }

  if (SECITEM_CompareItem(&mfDigest, &mfCalculatedDigest.get()) != SECEqual) {
    return NS_ERROR_SIGNED_JAR_MANIFEST_INVALID;
  }

  // Parse manifest and verify signed hash of all listed files

  // Allocate the I/O buffer only once per JAR, instead of once per entry, in
  // order to minimize malloc/free calls and in order to avoid fragmenting
  // memory.
  ScopedAutoSECItem buf(128 * 1024);

  nsTHashtable<nsStringHashKey> items;
  rv = ParseMFUnpacked(char_ptr_cast(manifestBuffer.data),
                       aDirectory, items, buf);
  if (NS_FAILED(rv)){
    return rv;
  }

  // We've checked that everything listed in the manifest exists and is signed
  // correctly. Now check on disk for extra (unsigned) files.
  // Deletes found entries from items as it goes.
  rv = CheckDirForUnsignedFiles(aDirectory, EmptyString(), items,
                                sigFilename, sfFilename, mfFilename);
  if (NS_FAILED(rv)) {
    return rv;
  }

  // We verified that every entry that we require to be signed is signed. But,
  // were there any missing entries--that is, entries that are mentioned in the
  // manifest but missing from the directory tree? (There shouldn't be given
  // ParseMFUnpacked() checking them all, but it's a cheap sanity check.)
  if (items.Count() != 0) {
    return NS_ERROR_SIGNED_JAR_ENTRY_MISSING;
  }

  // Return the signer's certificate to the reader if they want it.
  // XXX: We should return an nsIX509CertList with the whole validated chain.
  if (aSignerCert) {
    MOZ_ASSERT(CERT_LIST_HEAD(builtChain));
    nsCOMPtr<nsIX509Cert> signerCert =
      nsNSSCertificate::Create(CERT_LIST_HEAD(builtChain)->cert);
    NS_ENSURE_TRUE(signerCert, NS_ERROR_OUT_OF_MEMORY);
    signerCert.forget(aSignerCert);
  }

  return NS_OK;
}

class VerifySignedDirectoryTask final : public CryptoTask
{
public:
  VerifySignedDirectoryTask(AppTrustedRoot aTrustedRoot, nsIFile* aUnpackedJar,
                            nsIVerifySignedDirectoryCallback* aCallback)
    : mTrustedRoot(aTrustedRoot)
    , mDirectory(aUnpackedJar)
    , mCallback(new nsMainThreadPtrHolder<nsIVerifySignedDirectoryCallback>(aCallback))
  {
  }

private:
  virtual nsresult CalculateResult() override
  {
    return VerifySignedDirectory(mTrustedRoot,
                                 mDirectory,
                                 getter_AddRefs(mSignerCert));
  }

  // This class doesn't directly hold NSS resources so there's nothing that
  // needs to be released
  virtual void ReleaseNSSResources() override { }

  virtual void CallCallback(nsresult rv) override
  {
    (void) mCallback->VerifySignedDirectoryFinished(rv, mSignerCert);
  }

  const AppTrustedRoot mTrustedRoot;
  const nsCOMPtr<nsIFile> mDirectory;
  nsMainThreadPtrHandle<nsIVerifySignedDirectoryCallback> mCallback;
  nsCOMPtr<nsIX509Cert> mSignerCert; // out
};

NS_IMETHODIMP
nsNSSCertificateDB::VerifySignedDirectoryAsync(
  AppTrustedRoot aTrustedRoot, nsIFile* aUnpackedJar,
  nsIVerifySignedDirectoryCallback* aCallback)
{
  NS_ENSURE_ARG_POINTER(aUnpackedJar);
  NS_ENSURE_ARG_POINTER(aCallback);
  RefPtr<VerifySignedDirectoryTask> task(new VerifySignedDirectoryTask(aTrustedRoot,
                                                                       aUnpackedJar,
                                                                       aCallback));
  return task->Dispatch("UnpackedJar");
}