This file is indexed.

/usr/share/perl5/WebLogin.pm is in libwebkdc-perl 4.6.1-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   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
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
# WebLogin interactions with the browser for WebAuth
#
# Written by Roland Schemers <schemers@stanford.edu>
# Extensive updates by Russ Allbery <eagle@eyrie.org>
# Rewritten for CGI::Application by Jon Robertson <jonrober@stanford.edu>
# Copyright 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012,
#     2013, 2014 The Board of Trustees of the Leland Stanford Junior University
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to
# deal in the Software without restriction, including without limitation the
# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
# sell copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
# IN THE SOFTWARE.

##############################################################################
# Modules and declarations
##############################################################################

package WebLogin;
use base qw (CGI::Application);
use CGI::Application::Plugin::AutoRunmode;
use CGI::Application::Plugin::Forward;
use CGI::Application::Plugin::Redirect;
use CGI::Application::Plugin::TT;

require 5.006;

use strict;
use warnings;

use CGI::Cookie ();
use MIME::Base64 qw(encode_base64 decode_base64);
use POSIX qw(strftime);
use Template ();
use Time::Duration;
use URI ();
use URI::QueryParam ();
use WebAuth 3.06 qw(:const);
use WebKDC 2.06;
use WebKDC::Config 1.00;
use WebKDC::WebKDCException 1.05;

# Required only if we're going to do replay caching or rate limiting.
if (@WebKDC::Config::MEMCACHED_SERVERS) {
    require Cache::Memcached;
    require Digest::SHA;
}

# Required if we're going to send remctl commands for multifactor.
if ($WebKDC::Config::MULTIFACTOR_SERVER) {
    require Net::Remctl;
}

our $VERSION;

# This version matches the version of WebAuth with which this module was
# released, but with two digits for the minor and patch versions.
BEGIN {
    $VERSION = '4.0601';
}

# The CGI::Application parameters that must be cleared for each query.
our @PER_QUERY_PARAMS = qw(
    CPT is_error forced_login pretty_uri remuser_failed remuser_url
    script_name wpt_cookie
);

##############################################################################
# Configuration defaults
##############################################################################

# Set to true in order to enable debugging output.  This will be very chatty
# in the logs and may log security-sensitive tokens and other information.
our $DEBUG = 0;

# Set to true to log interesting error messages to stderr.
our $LOGGING = 1;

# The name of the cookie we set to ensure that the browser can handle cookies.
our $TEST_COOKIE = "WebloginTestCookie";

# The name of the cookie holding REMOTE_USER configuration information.
our $REMUSER_COOKIE = 'weblogin_remuser';

# Set any cookies we expire to this value, just in case a buggy browser
# refuses to actually delete the expired cookie.
our $EXPIRED_COOKIE = 'expired';

# The lifetime of the REMOTE_USER configuration cookie.
our $REMUSER_LIFETIME = '+365d';

# The lifetime of the kadmin/changepw token.
our $CHANGEPW_EXPIRES = 5 * 60;

# If the WebKDC is localhost, disable LWP certificate verification.  The
# WebKDC will have a certificate matching its public name, which will
# never match localhost, and we should be able to trust the server when
# connecting directly to localhost.
if ($WebKDC::Config::URL =~ m,^https://localhost/,) {
    $ENV{PERL_LWP_SSL_VERIFY_HOSTNAME} = 0;
}

#############################################################################
# CGI::Application setup functions
#############################################################################

# Set up initial application configuration.
sub setup {
    my ($self) = @_;

    # Configure the template.
    $self->tt_config(
                     TEMPLATE_OPTIONS => {
                         STAT_TTL     => 60,
                         COMPILE_DIR  =>
                             $WebKDC::Config::TEMPLATE_COMPILE_PATH,
                         COMPILE_EXT  => '.ttc',
                         INCLUDE_PATH => $WebKDC::Config::TEMPLATE_PATH,
                         EVAL_PERL    => 1,
                     },
                    );

    # Testing and logging - optional.  These can be set from the calling
    # script via:
    #    my $app = WebLogin->new(PARAMS => { logging => 1, debug => 1 });
    if (!defined $self->param ('logging')) {
        $self->param ('logging', $LOGGING);
    }
    if (!defined $self->param ('debug')) {
        $self->param ('debug', $DEBUG);
    }

    # Cookie values - optional.  See the logging comment above for how to set
    # from calling script.
    if (!defined $self->param ('remuser_cookie')) {
        $self->param ('remuser_cookie', $REMUSER_COOKIE);
    }
    if (!defined $self->param ('remuser_lifetime')) {
        $self->param ('remuser_lifetime', $REMUSER_LIFETIME);
    }
    if (!defined $self->param ('test_cookie')) {
        $self->param ('test_cookie', $TEST_COOKIE);
    }

    # If rate limiting or replay caching is enabled, connect to the memcached
    # server.
    if (@WebKDC::Config::MEMCACHED_SERVERS) {
        $self->{memcache} = Cache::Memcached->new ({
            servers => [ @WebKDC::Config::MEMCACHED_SERVERS ]
        });
    }
}

# Hook called before processing of each query.
sub cgiapp_prerun {
    my ($self) = @_;

    # Reset the header type and all header properties for clean state for
    # each request.
    $self->header_props ({});
    $self->header_type ('header');

    # Clear any per-query state that was stored as parameters.
    for my $param (@PER_QUERY_PARAMS) {
        $self->param ($param, undef);
    }

    # Clear all template parameters.
    $self->param ('template_params', {});
    $self->tt_clear_params;

    # The WebAuth object is per-query to do APR garbage collection.
    $self->{webauth} = WebAuth->new;

    # Set up the main request and response.
    $self->{request} = WebKDC::WebRequest->new;
    $self->{response} = WebKDC::WebResponse->new;

    # If we got our parameters via REDIRECT_QUERY_STRING, we're an error
    # handler and don't want to redirect later.
    $self->param ('is_error', defined $ENV{REDIRECT_QUERY_STRING});

    # Store the CPT if one was already generated, so that we have one place to
    # check.
    $self->param ('CPT', $self->query->param ('CPT'));

    # Work around a bug in CGI that doesn't always set the script name.
    $self->query->{'.script_name'} = $ENV{SCRIPT_NAME};

    # Stash the script name as a parameter so that it can be easily updated
    # when we switch between password and login scripts.
    $self->param ('script_name', $self->query->script_name);
    print STDERR "Script name is ", $self->query->script_name, "\n"
        if $self->param ('debug');
}

##############################################################################
# Utility functions
##############################################################################

# Escape special characters in the principal name to match the escaping done
# by krb5_unparse_name.  This hopefully will make the principal suitable for
# passing to krb5_parse_name and getting the same results as the original
# unescaped principal.
sub krb5_escape {
    my ($self, $principal) = @_;
    $principal =~ s/\\/\\\\/g;
    $principal =~ s/\@/\\@/g;
    $principal =~ s/\t/\\t/g;
    $principal =~ s/\x08/\\b/g;
    $principal =~ s/\x00/\\0/g;
    return $principal;
}

# Encode a token for URL usage.
sub fix_token {
    my ($self, $token) = @_;
    $token =~ tr/ /+/;
    return $token;
}

# Check to see if the user has requested to remember their login device
# factor token.  To accomodate a form listing a checkbox for either yes or no
# depending on site preferences, we check to see if there is a settting, and
# if not, return the default.
#
# If the request method is GET, not POST, we're dealing with a single sign-on
# authentication, and we should always remember the login.
sub remember_login {
    my ($self) = @_;
    my $method = $self->query->request_method || 'POST';
    if ($method eq 'GET') {
        return 'yes';
    }
    if ($self->query->param ('remember_login')) {
        return $self->query->param ('remember_login');
    } else {
        return $WebKDC::Config::REMEMBER_FALLBACK;
    }
}

# Create and return a cookie that will expire an existing cookie.  Used in
# more than one place, so pulled out for logic.
sub expire_cookie {
    my ($self, $name, $secure) = @_;

    my $query = $self->query;
    my $cookie = $query->cookie (-name    => $name,
                                 -value   => $EXPIRED_COOKIE,
                                 -secure  => $secure,
                                 -expires => '-1d');
    return $cookie;
}

# Determine if we should clear a factor token.  We do this if the WebKDC sent
# some cookies but did not include a webkdc-factor token.  If it sent a
# webkdc-factor token, that will replace our current one, and if it sent no
# cookies at all, that may just be an initial login and we shouldn't clear any
# cookies.
sub should_clear_factor {
    my ($self) = @_;
    my $cookies = $self->{response}->cookies;
    if ($cookies && %{$cookies} && !exists $cookies->{webauth_wft}) {
        return 1;
    } else {
        return 0;
    }
}

# If there's a function pointer set in LOGIN_STATE_UNSERIALIZE, use that
# to parse and return the value of $login_state, else return the raw value.
sub parse_login_state {
    my ($self, $login_state) = @_;

    $login_state = decode_base64($login_state);
    if ( ref($WebKDC::Config::LOGIN_STATE_UNSERIALIZE) eq "CODE" ) {
        my $decoder = $WebKDC::Config::LOGIN_STATE_UNSERIALIZE;
        $login_state = &{$decoder}($login_state);
    }
    return $login_state;
}

##############################################################################
# Output related functions
##############################################################################

# Wrapper to help store current template settings.  We need to set template
# parameters all over and collect them together in the end.  tt_params does
# what we want, but it has precedence over things you pass in normally on
# actual template building, which means we'd have to use it throughout the
# actual print function as well.  There should be nothing wrong with that, but
# still, I'd rather just create things this way, as it 'feels' cleaner.
# Return the parameter hashref.
sub template_params {
    my ($self, $settings) = @_;

    my $params = $self->param ('template_params');
    if (defined $settings) {
        for my $key (keys %$settings) {
            $params->{$key} = $settings->{$key};
        }
        $self->param ('template_params', $params);
    }

    return $params;
}

# Given a page type, return the template URL from the param hash it's stored
# in.  This could be done as a two-liner everywhere in the code, but it's a
# little more readable to have this do the guts for us.  Returns a string of
# the page template filename, or '' if none found.
sub get_pagename {
    my ($self, $pagetype) = @_;
    my $pages = $self->param ('pages');
    my $pagename = $pages->{$pagetype};
    return $pagename if defined $pagename;

    print STDERR "could not find a page template of type $pagetype\n"
        if $self->param ('logging');
    return '';
}

# Print the headers for a page.  Takes the user's query and any additional
# cookies to set as parameters, and always adds the test cookie.  Skip any
# remuser proxy tokens, since those are internal and we want to reauthenticate
# the user every time.  Takes an optional redirection URL and an optional
# parameter saying that this is a post redirect.
sub print_headers {
    my ($self, $args) = @_;
    my $return_url   = $args->{return_url};
    my $use_303      = $args->{use_303};
    my $confirm_page = $args->{confirm_page};
    my $q            = $self->query;

    # Merge the cookies the browser sent with the ones we got from the WebKDC
    # response in a way that the latter overrides the former.  We want to see
    # the full set for the logic around expiring cookies during a login from a
    # public system to work properly.
    my %cookies;
    my %browser_cookies = CGI::Cookie->fetch;
    while (my ($name, $cookie) = each %browser_cookies) {
        $cookies{$name}{value} = $cookie->value;
    }
    if ($args->{cookies}) {
        for my $name (keys %{ $args->{cookies} }) {
            $cookies{$name} = $args->{cookies}{$name};
        }
    }

    # REMUSER_COOKIE is handled as a special case, since it stores user
    # preferences and should be retained rather than being only a session
    # cookie.  Any cookies sent us with no value should be deleted -- that's
    # how the WebKDC tells us a proxy token is invalid.
    my $remuser_name = $self->param ('remuser_cookie');
    my $remuser_lifetime = $self->param ('remuser_lifetime');
    my $secure = (defined ($ENV{HTTPS}) && $ENV{HTTPS} eq 'on') ? 1 : 0;
    my @ca;
    while (my ($name, $attrs) = each %cookies) {
        next if $name eq 'webauth_wpt_remuser';
        my $value      = $attrs->{value};
        my $expiration = $attrs->{expiration};
        my $cookie;

        # Expire the cookies with no values.
        if (($name =~ /^webauth_wpt/ || $name eq 'webauth_wft') && !$value) {
            $cookie = $self->expire_cookie ($name, $secure);

        # If told not to remember the login, expire the SSO cookies on display
        # of the confirmation page or any final redirect to WAS.
        } elsif ($name =~ /^webauth_wpt_/ && $confirm_page
                 && $self->remember_login eq 'no') {
            $cookie = $self->expire_cookie ($name, $secure);

        # Likewise for any webkdc-factor token.
        } elsif ($name eq 'webauth_wft' && $confirm_page
                 && $self->remember_login eq 'no') {
            $cookie = $self->expire_cookie ($name, $secure);

        # Pass along the remuser cookie and update its expiration.
        } elsif ($name eq $remuser_name) {
            $cookie = $q->cookie (-name    => $name,
                                  -value   => $value,
                                  -secure  => $secure,
                                  -expires => $remuser_lifetime);

        # Pass along a factor token with set lifetime.
        } elsif ($name eq 'webauth_wft') {
            $cookie = $q->cookie (-name    => $name,
                                  -value   => $value,
                                  -secure  => $secure);

            # Set expiration if one is given.
            if ($expiration) {
                my @expires = gmtime ($expiration);
                my $lifetime = strftime ("%a, %d-%b-%Y %T GMT", @expires);
                $cookie->expires ($lifetime);
            }

        # Pass along all other webkdc-proxy and webkdc-factor cookies.
        } elsif ($name =~ /^webauth_w[pf]t/) {
            $cookie = $q->cookie (-name     => $name,
                                  -value    => $value,
                                  -secure   => $secure,
                                  -httponly => 1);
        }

        # Add the cookie to the list of cookies we're setting if we created a
        # new cookie object.
        if (defined $cookie) {
            push (@ca, $cookie);
        }
    }

    # If we haven't been given a webauth factor token cookie explicitly, then
    # we want to expire any that exist.
    if ($self->should_clear_factor && $self->{request}->factor_token) {
        my $cookie = $self->expire_cookie ('webauth_wft', $secure);
        push (@ca, $cookie);
    }

    # Set the test cookie unless it's already set.
    unless ($q->cookie ($self->param ('test_cookie'))) {
        my $cookie = $q->cookie (-name     => $self->param ('test_cookie'),
                                 -value    => 'True',
                                 -secure   => $secure,
                                 -httponly => 1);
        push (@ca, $cookie);
    }

    # Now, print out the page header with the appropriate cookies and with all
    # the HTTP headers required to tell all browser to, no, really, don't
    # cache.
    my @params;
    if ($return_url) {
        push (@params, -location => $return_url,
              -status => $use_303 ? '303 See Also' : '302 Moved');
    }
    push (@params, -cookie => [@ca]) if @ca;
    my $cache_control = 'private, no-cache, no-store, max-age=0';
    $self->header_props (-type => 'text/html', -expires => '-1d',
                         -Pragma => 'no-cache', -Vary => '*',
                         -Cache_Control => $cache_control, @params);
    return '';
}

# Determine what pretty display URL to use from the given return URI object.
#
# This is a bit more complicated if we're using Shibboleth; in that case, try
# to extract a URI from the target parameter of the return URL.  If the target
# value not a valid URL (e.g. when the SP's localRelayState property is true,
# in which case the target value is "cookie"), fall back to using the value of
# the shire parameter, which is the location of the the authentication
# assertion handler.
#
# If we're not using Shibboleth, or if we can't parse the Shibboleth URL and
# find the SP, just return the scheme and host of the return URL.
sub pretty_return_uri {
    my ($self, $uri) = @_;
    my $pretty;
    if (grep { $uri->host eq $_ } @WebKDC::Config::SHIBBOLETH_IDPS) {
        my $dest;
        my $target = $uri->query_param ('target');
        if ($target) {
            $dest = URI->new ($target);
        }
        unless ($dest && $dest->scheme && $dest->scheme =~ /^https?$/) {
            my $shire = $uri->query_param ('shire');
            if ($shire) {
                $dest = URI->new ($shire);
            }
        }
        if ($dest && $dest->scheme && $dest->scheme =~ /^https?$/) {
            $pretty = $dest->scheme . "://" . $dest->host;
        }
    }

    # The non-Shibboleth case.  Just use the scheme and host.
    unless ($pretty) {
        $pretty = $uri->scheme . "://" . $uri->host;
    }

    return $pretty;
}

# Parse the return URL of our request, saving the prettified uri.  Make sure
# that the scheme exists and is a valid WebAuth scheme.  Return 0 if
# everything is okay, 1 if the scheme is invalid.
sub parse_uri {
    my ($self) = @_;
    my $resp = $self->{response};
    my $uri = URI->new ($resp->return_url);
    my $scheme = $uri->scheme;
    unless (defined ($scheme) && $scheme =~ /^https?$/) {
        $self->template_params ({err_webkdc => 1});
        return 1;
    }

    $self->param ('pretty_uri', $self->pretty_return_uri ($uri));
    return 0;
}

# Parse the token.acl file and return a reference to a list of the credentials
# that the requesting WAS is permitted to obtain.  Takes the WebKDC response,
# from which it obtains the requesting identity.
sub token_rights {
    my ($self) = @_;
    my $resp = $self->{response};

    return [] unless $WebKDC::Config::TOKEN_ACL;
    unless (open (ACL, '<', $WebKDC::Config::TOKEN_ACL)) {
        return [];
    }
    my $requester = $resp->requester_subject;
    my $rights = [];
    local $_;
    while (<ACL>) {
        s/\#.*//;
        next if /^\s*$/;
        my ($id, $token, $type, $name) = split;
        next unless $token eq 'cred';
        next unless $id =~ s/^krb5://;
        $id = quotemeta $id;
        $id =~ s/\\*/[^\@]*/g;
        next unless $requester =~ /$id/;
        my $data = {};
        $data->{type} = $type;
        $data->{name} = $name;
        if ($type eq 'krb5') {
            my ($principal, $realm) = split ('@', $name, 2);
            my $instance;
            ($principal, $instance) = split ('/', $principal, 2);
            $data->{principal} = $principal;
            $data->{instance}  = $instance;
            $data->{realm}     = $realm;
        }
        push (@$rights, $data);
    }
    close ACL;
    return $rights;
}

# Obtains the login cancel URL and sets appropriate parameters in the login
# page if one is present.
#
# FIXME: Duplicates some of the logic of print_confirm_page but uses slightly
# different template parameters.  This is annoying and should be standardized.
sub get_login_cancel_url {
    my ($self) = @_;
    my $resp = $self->{response};
    my $lc = $resp->login_canceled_token;
    my $cancel_url;

    # FIXME: Looks like extra semicolons here too.
    if ($lc) {
        $cancel_url = $resp->return_url . "?WEBAUTHR=$lc;";
        $cancel_url .= ";WEBAUTHS=" . $resp->app_state . ";"
            if $resp->app_state;
    }
    if ($cancel_url) {
        $self->template_params ({login_cancel => 1});
        $self->template_params ({cancel_url => $cancel_url});
    }

    return 0;
}

##############################################################################
# Actual page views
##############################################################################

# Print the login page.  Takes the query, the variable hash, the error code if
# any, the WebKDC response, the request token, and the service token, and
# encodes them as appropriate in the login page.
sub print_login_page {
    my ($self, $err, $RT, $ST) = @_;
    my $q = $self->query;

    my $pagename = $self->get_pagename ('login');
    my $params = $self->template_params;
    $params->{script_name} = $self->param ('script_name');
    $params->{username} = $q->param ('username');
    $params->{RT} = $RT;
    $params->{ST} = $ST;
    $params->{remember_login} = $self->remember_login;
    if ($self->param ('remuser_url')) {
        $params->{show_remuser} = 1;
        $params->{remuser_url} = $self->param ('remuser_url');
    }
    if ($self->param ('remuser_failed')) {
        $params->{remuser_failed} = 1;
    }

    # If and only if we got here as the target of a form submission (meaning
    # that they already had one shot at logging in and something didn't work),
    # set the appropriate error status.
    #
    # If they *haven't* already had one shot and forced login is set, display
    # the error box telling them they're required to log in.
    if ($q->param ('login')) {
        $params->{err_password} = 1 unless $q->param ('password');
        $params->{err_username} = 1 unless $q->param ('username');
        $params->{err_missinginput} = 1 if $params->{'err_username'};
        $params->{err_missinginput} = 1 if $params->{'err_password'};
        if ($err == WK_ERR_LOGIN_FAILED) {
            $params->{err_loginfailed} = 1;
        }
        if ($err == WK_ERR_USER_REJECTED) {
            $params->{err_rejected} = 1;
        }

        # Set a generic error indicator if any of the specific ones were set
        # to allow easier structuring of the login page template.
        $params->{error} = 1 if $params->{'err_missinginput'};
        $params->{error} = 1 if $params->{'err_loginfailed'};
        $params->{error} = 1 if $params->{'err_rejected'};
    } elsif ($self->param ('forced_login')) {
        $params->{err_forced} = 1;
        $params->{error} = 1;
    }

    my %args = (cookies => $self->{response}->cookies);
    $self->print_headers (\%args);
    my $content = $self->tt_process ($pagename, $params);
    if ($content) {
        return $content;
    } else {
        $self->print_error_fatal ('could not process login template');
    }
}

# Print an error page, making sure that error pages are never cached.
sub print_error_page {
    my ($self) = @_;
    my $pagename = $self->get_pagename ('error');
    my $resp = $self->{response};
    my $params = $self->template_params;
    my $q = $self->query;

    # If there is a login cancel option, handle creating the link for it.
    my $lc = $resp->login_canceled_token;
    if (defined $lc) {
        $params->{login_cancel} = 1;
        my $cancel_url = $resp->return_url;

        # FIXME: Looks like extra semicolons here too.
        $cancel_url .= "?WEBAUTHR=$lc;";
        $cancel_url .= ";WEBAUTHS=" . $resp->app_state . ";"
            if $resp->app_state;
        $params->{cancel_url} = $cancel_url;
    }

    # If the user has been locked out due to hitting the rate limit, force
    # expiration of any persistent factor cookies and proxy cookies by marking
    # this as a public computer.
    if ($params->{err_lockout}) {
        $q->param ('remember_login', 'no');
    }

    # Print out the error page.
    my %args = (cookies => $resp->cookies);
    $self->print_headers (\%args);
    my $content = $self->tt_process ($pagename, $params);
    if ($content) {
        return $content;
    } else {
        $self->print_error_fatal ('could not process error template');
    }
}

# In case of a fatal error, such as being unable to process a template, we
# either print out a given 500 error page, or die to have Apache handle it
# for us.
sub print_error_fatal {
    my ($self, $error) = @_;
    my $q = $self->query;

    if ($WebKDC::Config::FATAL_PAGE && -f $WebKDC::Config::FATAL_PAGE
        && open (FATAL, '<', $WebKDC::Config::FATAL_PAGE)) {

        warn ($error);
        my $page = '';
        while (<FATAL>) {
            $page .= $_;
        }
        return $page;
    } else {
        die ($error);
    }
}

# Given the query, the local variables, and the WebKDC response, print the
# confirmation page, filling in all of the various bits of data that the page
# template needs.
#
# Setting the runmode occurs in the actual template file.
sub print_confirm_page {
    my ($self) = @_;

    my $q                 = $self->query;
    my $resp              = $self->{response};
    my $pagename          = $self->get_pagename ('confirm');
    my $params            = $self->template_params;

    my $uri               = URI->new ($resp->return_url);
    my $pretty_return_url = $self->pretty_return_uri ($uri);
    my $return_url        = $resp->return_url;
    my $token_type        = $resp->response_token_type;
    my $user_message      = $self->{response}->user_message;

    # The code to return the response token type was added in WebAuth 3.6.1.
    # Provide a useful error message if the mod_webkdc is older than that.
    unless (defined $token_type) {
        warn 'token type not present in WebKDC response; mod_webkdc on the'
            . " WebKDC may be older than 3.6.1\n";
        $token_type = '';
    }

    # We saw one error in production where this function was called after an
    # apparently successful WebKDC interaction, but there was no response
    # token.  Make a sanity check for that case.
    if (!$resp->response_token) {
        return $self->print_error_fatal ('token missing in WebKDC response');
    }

    # FIXME: This looks like it generates extra, unnecessary semicolons, but
    # should be checked against the parser in the WebAuth module.
    $return_url .= "?WEBAUTHR=" . $resp->response_token . ";";
    $return_url .= ";WEBAUTHS=" . $resp->app_state . ";" if $resp->app_state;

    # Find out if the user is within the window to have a password warning.
    # Present this warning only if the request was a POST, indicating that the
    # user provided some authentication credentials.  This avoids warning
    # (and, more importantly, inserting a confirmation screen) if the user
    # otherwise could have just been redirected to the destination without any
    # WebLogin interaction, such as via REMOTE_USER or a single sign-on
    # cookie.
    my $expire_warning = 0;
    if ($q->request_method eq 'POST' && $WebKDC::Config::EXPIRING_PW_URL) {
        my $expiring = $resp->password_expiration;
        if (defined ($expiring)
            && (($expiring - time) < $WebKDC::Config::EXPIRING_PW_WARNING)) {

            # Set template variable for expiring password.
            # TODO: Remove expire_date after giving time to update templates.
            $expire_warning = 1;
            my $expire_date = localtime ($expiring);
            $params->{warn_expire} = 1;
            $params->{expire_date}      = $expire_date;
            $params->{expire_timestamp} = $expiring;
            $params->{pwchange_url}     = $WebKDC::Config::EXPIRING_PW_URL;

            # Create and set the kadmin/changepw token (unless we require the
            # user re-enter).
            if (!$WebKDC::Config::EXPIRING_PW_RESEND_PASSWORD) {
                $self->add_changepw_token;
                $params->{CPT} = $self->param ('CPT');
            } else {
                $params->{skip_username} = 1;
            }
        }
    }

    # Determine if a device factor cookie is about to expire, and set the
    # time at which it expires if so.
    my $factor_warning = 0;
    my $cookies = $resp->cookies;
    if ($cookies) {
        while (my ($name, $attrs) = each %{$cookies}) {
            next unless $name eq 'webauth_wft';
            my $expiration = $attrs->{expiration};
            if ($WebKDC::Config::FACTOR_WARNING + time > $expiration) {
                $factor_warning = 1;
                $params->{device_expiring} = $expiration;
            }
        }
    }

    # If configured to permit bypassing the confirmation page, the WAS
    # requested an id token (not a proxy token, which may indicate ticket
    # delegation), and the page was not the target of a POST, return a
    # redirect to the final page instead of displaying a confirmation page.
    # If the page was the target of the post, we'll return a 303 redirect
    # later on but present the regular confirmation page as the body in case
    # the browser doesn't support it.
    #
    # We also skip the bypass if the user has an upcoming password expiration
    # warning, if they have a login history from the WebKDC that needs to be
    # displayed due to suspicious activity, or if they've asserted an
    # authorization identity.
    my $post = ($q->request_method eq 'POST') ? 1 : 0;
    my $history = $resp->login_history;
    my $bypass = $WebKDC::Config::BYPASS_CONFIRM;
    $bypass = 0 if $expire_warning;
    $bypass = 0 if $factor_warning;
    $bypass = 0 if $history;
    $bypass = 0 if $resp->authz_subject;
    $bypass = 0 if $resp->permitted_authz;
    $bypass = 0 if $user_message;
    if ($bypass and $bypass eq 'id') {
        $bypass = ($token_type eq 'id') ? 1 : 0;
    }
    if ($token_type eq 'id') {
        if ($bypass and not $post) {
            my %args = (cookies      => $resp->cookies,
                        return_url   => $return_url,
                        confirm_page => 1);
            return $self->print_headers (\%args);
        }
    }

    # Find our page and set general template parameters.
    $params->{return_url}        = $return_url;
    $params->{username}          = $resp->subject;
    $params->{authz_subject}     = $resp->authz_subject;
    $params->{permitted_authz}   = [ $resp->permitted_authz ];
    $params->{pretty_return_url} = $pretty_return_url;
    $params->{token_rights}      = $self->token_rights;
    $params->{history}           = $history;
    $params->{user_message}      = $user_message;
    $params->{remember_login}    = $self->remember_login;
    $params->{ST}                = $q->param ('ST');
    $params->{RT}                = $q->param ('RT');

    # Create the login_state object for use in templates
    if ($self->{response}->login_state) {
        my $login_state = $self->{response}->login_state;
        $params->{LS} = $login_state;
        $params->{login_state} = $self->parse_login_state($login_state);
    }

    # If there is a login cancel option, handle creating the link for it.
    my $lc = $resp->login_canceled_token;
    if (defined $lc) {
        $params->{login_cancel} = 1;
        my $cancel_url = $resp->return_url;

        # FIXME: Looks like extra semicolons here too.
        $cancel_url .= "?WEBAUTHR=$lc;";
        $cancel_url .= ";WEBAUTHS=" . $resp->app_state . ";"
            if $resp->app_state;
        $params->{cancel_url} = $cancel_url;
    }

    # If REMOTE_USER is done at a separate URL *and* REMOTE_USER support was
    # either requested or used, show the checkbox for it.
    if ($WebKDC::Config::REMUSER_REDIRECT) {
        my $cookie_name = $self->param ('remuser_cookie');
        if ($ENV{REMOTE_USER} || $q->cookie ($cookie_name)) {
            $params->{show_remuser} = 1;
            $params->{script_name} = $self->param ('script_name');

            $params->{remuser} = 1 if $q->cookie ($cookie_name);
        }
    }

    # Print out the page, including any updated proxy cookies if needed.  If
    # we're suppressing the confirm page and the browser used HTTP/1.1, use
    # the HTTP 303 redirect code as well.
    if ($bypass && $ENV{SERVER_PROTOCOL} eq 'HTTP/1.1') {
        my %args = (cookies      => $resp->cookies,
                    return_url   => $return_url,
                    use_303      => 1,
                    confirm_page => 1);
        $self->print_headers (\%args);
    } else {
        my %args = (cookies      => $resp->cookies,
                    confirm_page => 1);
        $self->print_headers (\%args);
    }
    my $content = $self->tt_process ($pagename, $params);
    if ($content) {
        return $content;
    } else {
        $self->print_error_fatal ('could not process confirm template');
    }
}

# Given the query, redisplay the confirmation page after a change in the
# REMOTE_USER cookie.  Also set the new REMOTE_USER cookie.
#
# FIXME: We lose the token rights.  Maybe we should preserve the identity of
# the WAS in a hidden variable?
sub redisplay_confirm_page {
    my ($self) = @_;
    my $q = $self->query;

    my $username = $q->param ('username');
    my $return_url = $q->param ('return_url');
    my $uri = URI->new ($return_url);
    unless ($username && $uri && $uri->scheme && $uri->host) {
        $self->template_params ({err_confirm => 1});
        print STDERR "missing data when reconstructing confirm page\n"
            if $self->param ('logging');
        return $self->print_error_page;
    }
    my $pretty_return_url = $self->pretty_return_uri ($uri);

    # Find our page and set general template parameters.
    my $pagename = $self->get_pagename ('confirm');
    my $params = $self->template_params;
    $params->{return_url} = $return_url;
    $params->{username} = $username;
    $params->{pretty_return_url} = $pretty_return_url;
    $params->{script_name} = $self->param ('script_name');
    $params->{show_remuser} = 1;
    my $remuser = $q->param ('remuser') eq 'on' ? 'checked' : '';
    $params->{remuser} = $remuser;
    $params->{remember_login} = $self->remember_login;
    $params->{ST} = $q->param ('ST');
    $params->{RT} = $q->param ('RT');
    $params->{LS} = $q->param ('LS');

    # If there is a login cancel option, handle creating the link for it.
    my $cancel_url = $q->param ('cancel_url');
    if (defined $cancel_url) {
        $params->{login_cancel} = 1;
        $params->{cancel_url} = $cancel_url;
    }

    # Create a hash for the REMOTE_USER cookie.
    my $cookie_name = $self->param ('remuser_cookie');
    my $cookie_val  = $remuser ? 1 : 0;
    my %cookie = ($cookie_name => { value      => $cookie_val,
                                    expiration => 0});

    # Print out the page, including the new REMOTE_USER cookie.
    my %args = (cookies => \%cookie);
    $self->print_headers (\%args);
    my $content = $self->tt_process ($pagename, $params);
    if ($content) {
        return $content;
    } else {
        $self->print_error_fatal ('could not process confirm template');
    }
}

# Print the password change page.
sub print_pwchange_page {
    my ($self, $RT, $ST) = @_;
    my $q = $self->query;
    my $pagename = $self->get_pagename ('pwchange');
    my $params = $self->template_params;

    # Get and pass along various field values that remain across attempts.
    $params->{username} = $q->param ('username');
    $params->{CPT} = $self->param ('CPT');
    $params->{RT} = $RT;
    $params->{ST} = $ST;
    $params->{remember_login} = $self->remember_login;
    $params->{script_name} = $self->param ('script_name');
    $params->{expired} = 1
        if ($q->param ('expired') and $q->param ('expired') eq '1');

    # We don't need the user information if they have already acquired a
    # kadmin/changepw token, or at previous request to skip the username.
    if ($self->param ('CPT')) {
        $params->{skip_username} = 1;
        $params->{skip_password} = 1;
    } elsif (defined $q->param ('skip_username')
             && $q->param ('skip_username') == 1) {
        $params->{skip_username} = 1;
    }

    # Print out the page.
    $self->print_headers;
    my $content = $self->tt_process ($pagename, $params);
    if ($content) {
        return $content;
    } else {
        $self->print_error_fatal ('could not process pwchange template');
    }
}

# Print confirmation page after successful password change.  This is only
# hit when not having been sent here with an expired password.  We don't set
# a runmode, since this is an end state.
sub print_pwchange_confirm_page {
    my ($self) = @_;
    my $q = $self->query;
    my $pagename = $self->get_pagename ('pwchange');
    my $params = $self->template_params;

    $params->{success} = 1;
    $self->print_headers;
    my $content = $self->tt_process ($pagename, $params);
    if ($content) {
        return $content;
    } else {
        $self->print_error_fatal ('could not process pwchange confirm '
                                  .'template');
    }
}

# Print the page prompting a user to give a multifactor OTP.  This is called
# whenever the user's login attempt returns that multifactor should be tried,
# or on an unsuccessful attempt to use multifactor.
sub print_multifactor_page {
    my ($self, $RT, $ST) = @_;
    my $q = $self->query;
    my $pagename = $self->get_pagename ('multifactor');
    my $params = $self->template_params;

    $params->{script_name} = $self->param ('script_name');
    $params->{username} = $q->param ('username');
    $params->{remember_login} = $self->remember_login;
    $params->{user_message} = $self->{response}->user_message;
    $params->{RT} = $RT;
    $params->{ST} = $ST;

    # Default the factor type to anything saved from the previous page.
    $params->{factor_type} = $q->param ('factor_type');

    # Find just the o* factor to pass along to the template for any special
    # processing.  Start by looking for any o* configured factor.  This will
    # pick the last of the available o* configured factors.  Then, override
    # that with the desired factor if it wants something more specific.
    if ($self->{response}->factor_configured) {
        for my $factor (@{$self->{response}->factor_configured}) {
            next unless $factor =~ /^o\d+$/;
            $params->{factor_type} = $factor;
        }
    }
    if ($self->{response}->factor_needed) {
        foreach my $factor (@{$self->{response}->factor_needed}) {
            next unless $factor =~ /^o\d+$/;
            $params->{factor_type} = $factor;
        }
    }

    # Create the login_state object for use in templates
    if ($self->{response}->login_state) {
        my $login_state = $self->{response}->login_state;
        $params->{LS} = $login_state;
        $params->{login_state} = $self->parse_login_state($login_state);
    }

    $params->{error} = 1 if $params->{'err_multifactor_missing'};
    $params->{error} = 1 if $params->{'err_multifactor_invalid'};

    my %args = (cookies => $self->{response}->cookies);
    $self->print_headers (\%args);
    my $content = $self->tt_process ($pagename, $params);
    if ($content) {
        return $content;
    } else {
        $self->print_error_fatal ('could not process multifactor template');
    }
}

##############################################################################
# REMOTE_USER support
##############################################################################

# Redirect the user to the REMOTE_USER-enabled login URL.
sub print_remuser_redirect {
    my ($self) = @_;
    my $q = $self->query;
    my $uri = $WebKDC::Config::REMUSER_REDIRECT;

    unless ($uri) {
        print STDERR "REMUSER_REDIRECT not configured\n"
            if $self->param ('logging');
        $self->template_params ({err_webkdc => 1});
        my $errmsg = "unrecoverable error occured. Try again later.";
        $self->template_params ({err_msg => $errmsg});
        return $self->print_error_page;
    } else {
        $uri .= "?RT=" . $self->fix_token ($q->param ('RT')) .
                ";ST=" . $self->fix_token ($q->param ('ST'));
        print STDERR "redirecting to $uri\n" if $self->param ('debug');
        return $self->redirect ($uri);
    }
}

# Generate a proxy token using forwarded Kerberos credentials and pass it into
# the WebKDC with the other proxy tokens.
sub add_kerberos_proxy_token {
    my ($self) = @_;

    print STDERR "adding a proxy token for $ENV{REMOTE_USER}\n"
        if $self->param ('debug');
    my ($kreq, $data);
    my $principal = $WebKDC::Config::WEBKDC_PRINCIPAL;
    eval {
        my $context = $self->{webauth}->krb5_new;
        $context->init_via_cache;
        my ($tgt, $expires) = $context->export_cred;
        ($kreq, $data) = $context->make_auth ($principal, $tgt);
        $kreq = encode_base64 ($kreq, '');
        $data = encode_base64 ($data, '');
    };
    if ($@) {
        print STDERR "failed to create proxy token request for"
            . " $ENV{REMOTE_USER}: $@\n" if $self->param ('logging');
        return;
    }
    my ($status, $error, $token, $subject)
        = WebKDC::make_proxy_token_request ($kreq, $data);
    if ($status != WK_SUCCESS) {
        print STDERR "failed to obtain proxy token for $ENV{REMOTE_USER}:"
            . " $error\n" if $self->param ('logging');
        return;
    }
    print STDERR "adding krb5 proxy token for $subject\n"
        if $self->param ('debug');
    $self->{request}->proxy_cookie ('krb5', $token, 'k');
}

# Add a generic token to the set of tokens that we'll pass to the WebKDC.
# This function takes a reference to a hash of parameters as follows:
#
# proxy_type      - Proxy type of resulting token (default: remuser)
# proxy_subject   - Proxy subject of resulting token (default: WEBKDC:remuser)
# subject         - Authenticated identity of user
# expiration      - Expiration time (default: time + REMUSER_EXPIRES)
# initial_factors - Initial authentication factors (default: u)
# session_factors - Session authentication factors (default: u)
# loa             - Level of assurance (default: 0)
#
# The resulting token will be stored in the set of cookies in the WebKDC
# request.
#
# Returns: undef
sub add_generic_proxy_token {
    my ($self, $args_ref) = @_;
    my %args = %{$args_ref};
    my $wa   = $self->{webauth};

    # Set token defaults.
    $args{proxy_type}      ||= 'remuser';
    $args{proxy_subject}   ||= 'WEBKDC:remuser';
    $args{expiration}      ||= time + $WebKDC::Config::REMUSER_EXPIRES;
    $args{initial_factors} ||= 'u';
    $args{session_factors} ||= 'u';

    # Load the keyring we'll use for token encoding.
    use Carp;
    confess("null $wa") unless defined $wa;
    my $keyring = $wa->keyring_read ($WebKDC::Config::KEYRING_PATH);
    unless ($keyring) {
        warn "weblogin: unable to initialize a keyring from"
            . " $WebKDC::Config::KEYRING_PATH\n";
        return;
    }

    # Create a proxy token.
    my $token = WebAuth::Token::WebKDCProxy->new ($wa);
    $token->subject ($args{subject});
    $token->proxy_type ($args{proxy_type});
    $token->proxy_subject ($args{proxy_subject});
    $token->data ($args{subject});
    $token->expiration ($args{expiration});
    $token->initial_factors ($args{initial_factors});
    if (defined ($args{loa}) && $args{loa} > 0) {
        $token->loa ($args{loa});
    }

    # Add the token to the WebKDC request.
    my $token_string = $token->encode ($keyring);
    my $factors      = $args{session_factors};
    $self->{request}->proxy_cookie ('remuser', $token_string, $factors);
    return;
}

# Generate a proxy token containing the REMOTE_USER identity and pass it into
# the WebKDC along with the other proxy tokens.  Takes the request to the
# WebKDC that we're putting together.  If the REMOTE_USER isn't valid for some
# reason, log an error and don't do anything else.
sub add_remuser_token {
    my ($self) = @_;
    my $wa = $self->{webauth};

    print STDERR "adding a REMOTE_USER token for $ENV{REMOTE_USER}\n"
        if $self->param ('debug');

    # Make sure that any realm in REMOTE_USER is permitted.
    my $identity = $ENV{REMOTE_USER};
    my ($user, $realm) = split ('@', $identity, 2);
    if (@WebKDC::Config::REMUSER_PERMITTED_REALMS) {
        my $found = 0;
        $realm ||= '';
        for my $check (@WebKDC::Config::REMUSER_PERMITTED_REALMS) {
            if ($check eq $realm) {
                $found = 1;
                last;
            }
        }
        if (!$found) {
            warn "weblogin: realm mismatch in REMOTE_USER $ENV{REMOTE_USER}:"
                . ' saw ' . ($realm ? $realm : '""') . ' not in allowed list'
                . "\n";
            return;
        }
    }
    if (grep { $realm eq $_ } @WebKDC::Config::REMUSER_LOCAL_REALMS) {
        $identity = $user;
    }

    # If there's a callback defined for determining the initial and session
    # factors and level of assurance, make that callback.
    my ($ini, $sess, $loa);
    if (defined (&WebKDC::Config::remuser_factors)) {
        ($ini, $sess, $loa) = WebKDC::Config::remuser_factors ($identity);
    }

    # Add the token to the WebKDC request.
    $self->add_generic_proxy_token(
        {
            subject         => $identity,
            initial_factors => $ini,
            session_factors => $sess,
            loa             => $loa,
        }
    );
}

##############################################################################
# Password change functions
##############################################################################

# Create a kadmin/changepw token using the username and password.  Returns
# true on success and false on failure.
sub add_changepw_token {
    my ($self) = @_;
    my $wa = $self->{webauth};
    my $q = $self->query;
    my $username = $q->param ('username');
    my $password = $q->param ('password');

    # Don't bother if the token already is created.
    return 1 if $self->param ('CPT');

    print STDERR "adding a kadmin/changepw cred token for $username\n"
        if $self->param ('debug');

    # Create a ticket for the password change principal with the username and
    # password.
    my ($ticket, $expires, $changepw);
    if ($WebKDC::Config::PASSWORD_CHANGE_SERVER) {
        $changepw = $WebKDC::Config::PASSWORD_CHANGE_PRINC;
    }
    $changepw ||= 'kadmin/changepw';
    if ($WebKDC::Config::DEFAULT_REALM && $changepw !~ /\@/) {
        $changepw .= '@' . $WebKDC::Config::DEFAULT_REALM;
    }
    eval {
        my $context = $wa->krb5_new;
        $context->init_via_password ($username, $password, $changepw);
        ($ticket, $expires) = $context->export_cred ($changepw);
    };
    if ($@) {
        print STDERR "failed to create $changepw credential for $username:"
            . " $@\n" if $self->param ('logging');
        return;
    }

    # Token expires the sooner of when the ticket expires or our time limit.
    my $expires_limit = time + $CHANGEPW_EXPIRES;
    $expires = $expires_limit if $expires_limit < $expires;

    # Create the token to contain the credential.
    my $token = WebAuth::Token::Cred->new ($wa);
    $token->subject ($username);
    $token->type ('krb5');
    $token->service ($changepw);
    $token->data ($ticket);
    $token->creation (time);
    $token->expiration ($expires);

    # Add the token to the web page.
    my $keyring = $wa->keyring_read ($WebKDC::Config::KEYRING_PATH);
    unless ($keyring) {
        warn "weblogin: unable to initialize a keyring from"
            . " $WebKDC::Config::KEYRING_PATH\n";
        return;
    }
    $self->param ('CPT', $token->encode ($keyring));
    return 1;
}

# Attempt to change the user password using the changepw token.
sub change_user_password {
    my ($self) = @_;
    my $wa = $self->{webauth};
    my $q = $self->query;
    my ($status, $error);

    my $username = $q->param ('username');
    my $password = $q->param ('new_passwd1');
    my $cpt = $self->param ('CPT');

    print STDERR "changing password for $username\n"
        if $self->param ('debug');

    my $keyring = $wa->keyring_read ($WebKDC::Config::KEYRING_PATH);
    unless ($keyring) {
        warn "weblogin: unable to initialize a keyring from"
            . " $WebKDC::Config::KEYRING_PATH\n";
        return;
    }

    # Decode the credential token with keyring and token, then verify token
    # validity.  If we don't yet have a CPT, but do have the user's old
    # password (ie: they came straight to the change password page), create
    # one right now.  If there's an error actually decrypting the token, it's
    # likely expired.  Hide the actual error behind a simpler one for the
    # user.
    if (!$cpt && $q->param ('password')) {
        unless ($self->add_changepw_token) {
            return (WK_ERR_LOGIN_FAILED,
                    'cannot acquire passord change credentials');
        }
        $cpt = $self->param ('CPT');
    }
    my $token = eval { $wa->token_decode ($cpt, $keyring) };
    if ($@) {
        $self->param ('CPT', '');
        my $msg = "internal error";
        my $e = $@;
        if (ref $e and $e->isa('WebKDC::WebKDCException')) {
            print STDERR $e->message(), "\n" if $self->param ('logging');
            return ($e->status(), $msg);
        } elsif (ref $e and $e->isa('WebAuth::Exception')) {
            print STDERR "WebAuth exception while changing password: $e\n"
                if $self->param ('logging');
            if ($e->{status} == WA_ERR_TOKEN_EXPIRED) {
                $msg = "failed to change password for $username:"
                    . " timed out, re-enter old password";
            }
            return (WebKDC::WK_ERR_UNRECOVERABLE_ERROR, $msg);
        } elsif ($e) {
            return (WebKDC::WK_ERR_UNRECOVERABLE_ERROR, $msg);
        }
    } elsif (!$token->isa ('WebAuth::Token::Cred')) {
        my $e = "failed to change password for $username: "
            . 'CPT parameter is not a cred token';
        print STDERR $e, "\n" if $self->param ('logging');
        return (WebKDC::WK_ERR_UNRECOVERABLE_ERROR, $e);
    } elsif ($token->subject ne $username) {
        my $e = "failed to change password for $username: invalid username";
        print STDERR $e, "\n" if $self->param ('logging');
        return (WebKDC::WK_ERR_UNRECOVERABLE_ERROR, $e);
    } elsif ($token->type ne 'krb5') {
        my $e = "failed to change password for $username: "
            . "invalid credential type";
        print STDERR $e, "\n" if $self->param ('logging');
        return (WebKDC::WK_ERR_UNRECOVERABLE_ERROR, $e);
    }

    # Change the password and return any error status plus exception object.
    my $changepw;
    if ($WebKDC::Config::PASSWORD_CHANGE_SERVER) {
        $changepw = $WebKDC::Config::PASSWORD_CHANGE_PRINC;
    }
    $changepw ||= 'kadmin/changepw';
    if ($WebKDC::Config::DEFAULT_REALM && $changepw !~ /\@/) {
        $changepw .= '@' . $WebKDC::Config::DEFAULT_REALM;
    }
    eval {
        my $context = $wa->krb5_new;
        $context->import_cred ($token->data);
        my $args = { protocol => 'kpasswd' };
        if ($WebKDC::Config::PASSWORD_CHANGE_SERVER) {
            $args = {
                protocol   => 'remctl',
                host       => $WebKDC::Config::PASSWORD_CHANGE_SERVER,
                port       => $WebKDC::Config::PASSWORD_CHANGE_PORT,
                identity   => $changepw,
                command    => $WebKDC::Config::PASSWORD_CHANGE_COMMAND,
                subcommand => $WebKDC::Config::PASSWORD_CHANGE_SUBCOMMAND,
            };
        }
        $context->change_password ($password, $args);
    };
    my $e = $@;
    if (ref $e and $e->isa('WebKDC::WebKDCException')) {
        return ($e->status(), $e->message());
    } elsif (ref $e and $e->isa('WebAuth::Exception')) {
        return (WebKDC::WK_ERR_UNRECOVERABLE_ERROR, $e->error_message);
    } elsif ($e) {
        return (WebKDC::WK_ERR_UNRECOVERABLE_ERROR, $e);
    } else {
        return (WebKDC::WK_SUCCESS, undef);
    }
}

##############################################################################
# Test for various invalid requests
##############################################################################

# Check for cookies being enabled in the browser.
#
# If no cookies are found, this is either the first visit or cookies are
# disabled.  To determine which, reload the page as if we'd not already
# been here, but appending a flag to the URL indicating that we've tried
# to set a cookie.  The cookie should always be present the second time
# around.
#
# However, do not do this as the result of a POST; not only may it violate
# the HTTP/1.0 protocol for browsers that don't support 1.1, but if the
# user already got the login page, it's not clear how they couldn't have
# cookie support.  If we redirect them and strip out the username and
# password, we get a confusing error message or we have to throw the no
# cookie support error page.  Just continue on at that point and hope
# everything works.  We may be dealing with an automated script that wants
# to authenticate via POST without going through the test cookie dance.
#
# If the parameter is already set and we still don't have a cookie, the
# user has cookies disabled.  Display the error page.
sub error_if_no_cookies {
    my ($self) = @_;

    return undef if $self->query->cookie ($self->param ('test_cookie'));
    if (defined $self->query->param ('test_cookie')) {
        print STDERR "no cookie, even after redirection\n"
            if $self->param ('logging');
        $self->template_params ({err_cookies_disabled => 1});
        return $self->print_error_page;
    } elsif ($self->query->request_method ne 'POST') {
        $self->query->delete ('username', 'password', 'submit');
        $self->query->param (test_cookie => 1);
        my $return_url = $self->query->url (-query => 1);
        print STDERR "no cookie set, redirecting to $return_url\n"
            if $self->param ('debug');
        my %args = (return_url => $return_url);
        return $self->print_headers (\%args);
    } else {
        return undef;
    }
}

# If the user sent a password, force POST as a method.  Otherwise, if we
# continue, the password may show up in referrer strings sent by the
# browser to the remote site.
sub error_password_no_post {
    my ($self) = @_;
    my $q = $self->query;

    return undef unless $q->param ('password')
        && $q->request_method ne 'POST';

    $self->template_params ({err_bad_method => 1});
    return $self->print_error_page;
}

# Check to see if we have request and webkdc-service tokens.  If not, display
# the error page and tell the caller to skip to the next request.  Returns
# undef on success and the page text on failure.
sub error_no_request_token {
    my ($self) = @_;
    my $q = $self->query;

    if ($q->param ('RT') && $q->param ('ST')) {
        return;
    } else {
        $self->template_params ({err_no_request_token => 1});
        print STDERR "no request or service token\n"
            if $self->param ('logging');
        return $self->print_error_page;
    }
}

# Test for requirements of a password request:
#   Username (Unless already authed)
#   Current password (Unless already authed)
#   Two prompts for new password (must match)
#
# Check to see if all required fields for a password change form have been
# filled out correctly.  If so, return 1.  If not, print the password
# change page again, with the errors, and return 0.
sub error_invalid_pwchange_fields {
    my ($self) = @_;
    my $q = $self->query;
    my $error;

    # Even if it's a hidden field and not given to user, this should exist.
    if (!$q->param ('username')) {
        $self->template_params ({err_username => 1});
        $error = 1;
    }

    # For password, we do not require it if we already have a kadmin/changepw
    # token.
    if (!$q->param ('password') && !$self->param ('CPT')) {
        $self->template_params ({err_password => 1});
        $error = 1;

    # Check both for empty new password, and for it to not match itself.
    } elsif (!$q->param ('new_passwd1') || !$q->param ('new_passwd2')) {
        $self->template_params ({err_newpassword => 1});
        $error = 1;
    } elsif ($q->param ('new_passwd1') ne $q->param ('new_passwd2')) {
        $self->template_params ({err_newpassword_match => 1});
        $error = 1;
    }

    return undef unless $error;

    # Mark us as having had an error and print the page again.
    $self->template_params ({error => 1});
    return $self->print_pwchange_page ($q->param ('RT'), $q->param ('ST'));
}

##############################################################################
# Rate limiting and replay caching
##############################################################################

# Check whether a given request is a replay.  Takes the request token and
# returns true if it is a replay, false otherwise (including if we aren't
# checking for replays).
sub is_replay {
    my ($self, $rt) = @_;
    if (!$self->{memcache} || !$WebKDC::Config::REPLAY_TIMEOUT) {
        return;
    }
    my $hash = Digest::SHA::sha512_base64 ($rt);
    print STDERR "Looking up request token hash $hash\n"
        if $self->param ('debug');
    my $seen = $self->{memcache}->get ("rt:$hash");
    if ($seen) {
        print STDERR "Rejecting request token $rt as a replay, last seen "
            . strftime ('%Y-%m-%d %T', localtime $seen) . "\n"
            if $self->param ('logging');
        print STDERR "Replacing request token hash $hash\n"
            if $self->param ('debug');
        my $now = time;
        my $expires = $now + $WebKDC::Config::REPLAY_TIMEOUT;
        $self->{memcache}->replace ("rt:$hash", $now, $expires);
        return 1;
    }
    return;
}

# Check whether a given username is rate limited.  Takes the username and
# returns true if they are, false otherwise (including if we aren't doing rate
# limiting).
sub is_rate_limited {
    my ($self, $username) = @_;
    if (!$self->{memcache} || !$WebKDC::Config::RATE_LIMIT_THRESHOLD) {
        return;
    }
    my $count = $self->{memcache}->get ("fail:$username");
    if (defined $count && $count >= $WebKDC::Config::RATE_LIMIT_THRESHOLD) {
        print STDERR "Rate limited authentication for $username\n"
            if $self->param ('logging');
        return 1;
    }
    return;
}

# Register a successful authentication using a request token so that we can
# detect if it is replayed.  Takes the request token and the username.
sub register_auth {
    my ($self, $rt, $username) = @_;
    if (!$self->{memcache} || !$WebKDC::Config::REPLAY_TIMEOUT) {
        return;
    }
    my $hash = Digest::SHA::sha512_base64 ($rt);
    print STDERR "Storing request token hash $hash\n"
        if $self->param ('debug');
    my $now = time;
    my $timeout = $now + $WebKDC::Config::REPLAY_TIMEOUT;
    $self->{memcache}->set ("rt:$hash", $now, $timeout);
    if ($WebKDC::Config::RATE_LIMIT_THRESHOLD) {
        $self->{memcache}->delete ("fail:$username");
    }
}

# Register a failed authentication for rate limiting.  Takes the username.
sub register_auth_fail {
    my ($self, $username) = @_;
    if (!$self->{memcache} || !$WebKDC::Config::RATE_LIMIT_THRESHOLD) {
        return;
    }
    print STDERR "Storing $username authentication failure for rate limit\n"
        if $self->param ('debug');
    my $expires = time + $WebKDC::Config::RATE_LIMIT_INTERVAL;
    my $count = $self->{memcache}->get ("fail:$username");
    if (!defined $count) {
        $count = 0;
    }
    $count++;
    $self->{memcache}->set ("fail:$username", $count, $expires);
}

##############################################################################
# KDC interactions
##############################################################################

# Set up all parameters to the WebKDC request, including tokens, username
# and password, proxy tokens, logging information, and REMOTE_USER
# information.  Takes a hash of cookies.
sub setup_kdc_request {
    my ($self, %cart) = @_;
    my $status = WK_SUCCESS;
    my $q      = $self->query;

    # Set up the parameters to the WebKDC request.
    $self->{request}->service_token ($self->fix_token ($q->param ('ST')))
        if $q->param ('ST');
    $self->{request}->request_token ($self->fix_token ($q->param ('RT')))
        if $q->param ('RT');
    $self->{request}->pass ($q->param ('password'))
        if $q->param ('password');
    $self->{request}->otp ($q->param ('otp'))
        if $q->param ('otp');
    $self->{request}->otp_type ($q->param ('factor_type'))
        if $q->param ('factor_type');
    $self->{request}->authz_subject ($q->param ('authz_subject'))
        if $q->param ('authz_subject');
    $self->{request}->login_state ($q->param ('LS'))
        if $q->param ('LS');

    # For the initial login page and password change page, we may need to map
    # the username.  For OTP, we've already done this, so we don't need to do
    # it again.
    if ($q->param ('password') && $q->param ('username')) {
        my $username = $q->param ('username');
        if (defined (&WebKDC::Config::map_username)) {
            $username = WebKDC::Config::map_username ($username);
        }
        if (defined $username) {
            if ($WebKDC::Config::DEFAULT_REALM && $username !~ /\@/) {
                $username .= '@' . $WebKDC::Config::DEFAULT_REALM;
            }
        } else {
            $username = '';
            $status = WK_ERR_LOGIN_FAILED;
        }
        $q->param ('username', $username);
    }
    $self->{request}->user ($q->param ('username')) if $q->param ('username');

    # Check for replays or rate limiting of failed authentications for the
    # initial login page, the multifactor login page, and the multifactor_send
    # page.
    if ($q->param ('username')
          && ($q->param ('password') || $q->param ('otp')
              || ($q->param ('rm')
                  && $q->param ('rm') eq 'multifactor_sendauth'))) {
        my $username = $q->param ('username');

        # Check for replay.  The request token won't exist if we're processing
        # a password change instead of an authentication.
        if ($self->{request}->request_token) {
            if ($self->is_replay ($self->{request}->request_token)) {
                $status = WK_ERR_AUTH_REPLAY;
            }
        }

        # Check for rate limiting.  This applies to password changes as well
        # as authentications, since the password change screen could still be
        # used to guess the user's password otherwise.
        if ($self->is_rate_limited ($username)) {
            $status = WK_ERR_AUTH_LOCKOUT;
        }
    }

    # Also pass to the WebKDC any proxy tokens we have from cookies.
    # Enumerate all cookies that start with webauth_wpt (WebAuth Proxy Token)
    # and stuff them into the WebKDC request.
    my $wpt_cookie;
    for my $type (keys %cart) {
        next if not defined $q->cookie ($type);
        next if $q->cookie ($type) eq $EXPIRED_COOKIE;

        if ($type =~ /^webauth_wpt/) {
            my $short_type = $type;
            $short_type=~ s/^webauth_wpt_//;
            $self->{request}->proxy_cookie ($short_type, $q->cookie ($type),
                                            'c');
            print STDERR "found a cookie of type $type\n"
                if $self->param ('debug');
            $wpt_cookie = 1;
        } elsif ($type eq 'webauth_wft') {
            $self->{request}->factor_token ($q->cookie ($type));
        }
    }
    $self->param ('wpt_cookie', $wpt_cookie);

    # Pass in the network connection information.  This is only used for
    # additional logging in the WebKDC.
    $self->{request}->local_ip_addr ($ENV{SERVER_ADDR});
    $self->{request}->local_ip_port ($ENV{SERVER_PORT});
    $self->{request}->remote_ip_addr ($ENV{REMOTE_ADDR});
    $self->{request}->remote_ip_port ($ENV{REMOTE_PORT});

    # The WebKDC doesn't use this yet, but we might like to in the future.
    $self->{request}->remote_user ($ENV{REMOTE_USER});

    # If there is an authenticate callback defined, call it.  On failure, it
    # will return an empty list; on success, it will return a list of four
    # values: the authenticated identity, the initial factors, the session
    # factors, and the LoA.
    my $remuser_done;
    if (defined &WebKDC::Config::authenticate) {
        my ($id, $initial, $session, $loa) = WebKDC::Config::authenticate ();
        if (defined $loa) {
            my $args = {
                subject         => $id,
                initial_factors => $initial,
                session_factors => $session,
                loa             => $loa,
            };
            $self->add_generic_proxy_token ($args);
            $remuser_done = 1;
        }
    }

    # Provided that authenticate hasn't already done work, if
    # WebKDC::Config::REMUSER_ENABLED is set to a true value, see if we have a
    # ticket cache.  If so, obtain a proxy token in advance.  Otherwise,
    # cobble up a proxy token using the value of REMOTE_USER and add it to the
    # request.  This allows the WebKDC to trust Apache authentication
    # mechanisms like SPNEGO or client-side certificates if so configured.
    if (!$remuser_done) {
        if ($ENV{REMOTE_USER} && $WebKDC::Config::REMUSER_ENABLED) {
            if ($ENV{KRB5CCNAME} && $WebKDC::Config::WEBKDC_PRINCIPAL) {
                $self->add_kerberos_proxy_token;
            } else {
                $self->add_remuser_token;
            }
        }
    }
    return $status;
}

# Handle errors from the login process.  This code is shared between the login
# screen and the resubmission of the confirmation screen when the
# authorization identity was changed.
#
# Call this method with the status and the error message (if any).  The return
# value will be the page to display, which means that the caller can just
# return the return value of this method.
sub handle_login_error {
    my ($self, $status, $error) = @_;
    my $q = $self->query;
    my $req = $self->{request};
    my $resp = $self->{response};

    # WK_ERR_USER_AND_PASS_REQUIRED indicates the first visit to the login
    # page, WK_ERR_LOGIN_FAILED indicates the user needs to try logging in
    # again, and WK_ERR_LOGIN_FORCED indicates this site requires
    # username/password even if the user has other auth methods.

    # User's password has expired and we have somewhere to send them to get it
    # changed.  Get the CPT (unless we require resending the password) and
    # update the script name.
    # 1B
    if ($status == WK_ERR_CREDS_EXPIRED
        && defined ($WebKDC::Config::EXPIRING_PW_URL)) {

        if (!$WebKDC::Config::EXPIRING_PW_RESEND_PASSWORD) {
            $self->add_changepw_token;
        } else {
            $self->template_params ({skip_username => 1});
        }

        $self->param ('script_name', $WebKDC::Config::EXPIRING_PW_URL);
        $self->query->param ('expired', '1');
        return $self->print_pwchange_page ($req->request_token,
                                           $req->service_token);

    # Other authentication methods can be used, REMOTE_USER support is
    # requested by cookie, we're not already at the REMOTE_USER-authenticated
    # URL, and we're not an error handler (meaning that we haven't tried
    # REMOTE_USER and failed).  Redirect to the REMOTE_USER URL.
        # 1C - Should be doing this before actually trying the webkdc login.
        #      Shouldn't be checking for the status it's checking.
        #      Should check for cookie -- remove status check and move up in
        #         flow for initial visit.
    } elsif ($status == WK_ERR_USER_AND_PASS_REQUIRED
             && !$ENV{REMOTE_USER}
             && $q->cookie ($self->param ('remuser_cookie'))
             && !$self->param ('is_error')
             && !$q->param ('login')
             && $WebKDC::Config::REMUSER_REDIRECT) {
        print STDERR "redirecting to REMOTE_USER page\n"
            if $self->param ('debug');
        return $self->print_remuser_redirect;

    # We've tried REMOTE_USER and failed, the site has said that the user has
    # to use username/password no matter what, REMOTE_USER redirects are not
    # supported, or the user has already tried username/password.  Display the
    # login screen without the REMOTE_USER choice.
    # 1D -- Displaying traditional login screen.
    } elsif ($status == WK_ERR_USER_AND_PASS_REQUIRED
             || $status == WK_ERR_LOGIN_FORCED
             || $status == WK_ERR_LOGIN_FAILED
             || $status == WK_ERR_USER_REJECTED) {
        if ($WebKDC::Config::REMUSER_REDIRECT) {
            $self->param ('remuser_failed', $self->param ('is_error'));
        }

        if ($status == WK_ERR_USER_AND_PASS_REQUIRED
            && !$q->cookie ($self->param ('remuser_cookie'))
            && !$self->param ('is_error')) {
            $self->param ('remuser_url', $WebKDC::Config::REMUSER_REDIRECT);
        }

        # If logins were forced, we want to tell the user.  However, if this
        # is the first site they've authenticated to, we only want to tell the
        # user that if they request REMUSER support.  So, if forced login was
        # set *and* either the user has single sign-on cookies or wants to do
        # REMUSER, set the relevant template variable.
        if ($status == WK_ERR_LOGIN_FORCED
            && ($self->param ('wpt_cookie')
                     || $q->cookie ($self->param ('remuser_cookie')))) {
            $self->param ('forced_login', 1);
        }

        # If the login failed, register that for rate limiting.
        if ($status == WK_ERR_LOGIN_FAILED) {
            $self->register_auth_fail ($req->user);
        }

        print STDERR "WebKDC::make_request_token_request failed,"
            . " displaying login page\n"
            if $self->param ('debug');
        return $self->print_login_page ($status, $req->request_token,
                                        $req->service_token);

    # Multifactor was required and the KDC says the user can give it.  If the
    # WebKDC knows who the user is, always use the authenticated identity from
    # the WebKDC, rather than whatever the user typed, since we may have done
    # Kerberos canonicalization during the authentication.
    } elsif ($status == WK_ERR_MULTIFACTOR_REQUIRED) {
        print STDERR "multifactor required for login\n"
            if $self->param ('debug');

        my $req = $self->{request};
        if (defined $resp->subject) {
            $q->param ('username', $resp->subject);
        }
        return $self->print_multifactor_page ($req->request_token,
                                              $req->service_token);

    # Multifactor was required but they have no or insufficiently high
    # multifactor configured.
    } elsif ($status == WK_ERR_MULTIFACTOR_UNAVAILABLE) {
        my $mf_setup = 0;
        foreach my $factor (@{$resp->factor_configured}) {
            $mf_setup = 1 if $factor eq 'm';
        }
        if ($mf_setup) {
            $self->template_params ({err_insufficient_mfactor => 1});
            $self->template_params ({multifactor_configured
                        => $resp->factor_configured });
            $self->template_params ({multifactor_required
                        => $resp->factor_needed });
        } else {
            $self->template_params ({err_no_mfactor => 1});
        }
        return $self->print_error_page;

    # Multifactor was configured, but at too low a level of assurance to
    # satisfy the destination site.
    } elsif ($status == WK_ERR_LOA_UNAVAILABLE) {
        $self->template_params ({err_insufficient_loa => 1});
        return $self->print_error_page;

    # The authentication was rejected, probably by the user information
    # service.  We may have a custom error message from the WebKDC and
    # therefore a custom error page to display to the user.
    } elsif ($status == WK_ERR_AUTH_REJECTED
             || $status == WK_ERR_LOGIN_REJECTED) {
        if ($error->data) {
            $self->template_params ({err_html => $error->data});
        } else {
            $self->template_params ({err_webkdc => 1});
            $self->template_params ({err_msg => 'authentication rejected.'});
        }
        return $self->print_error_page;

    # Request was a replay.  Users are only allowed to do a username and
    # password authentication with a given request token once, since otherwise
    # someone may use the back button in an abandoned browser to log in again.
    } elsif ($status == WK_ERR_AUTH_REPLAY) {
        $self->template_params ({err_replay => 1});
        return $self->print_error_page;

    # User reached the rate limit of failed logins.
    } elsif ($status == WK_ERR_AUTH_LOCKOUT) {
        $self->template_params ({err_lockout => 1});
        return $self->print_error_page;

    # Something abnormal happened.  Figure out what error message to display
    # and throw up the error page instead.
    } else {
        my $errmsg = '';

        # Something very nasty.  Just display a "we don't know" error.
        if ($status == WK_ERR_UNRECOVERABLE_ERROR) {
            $errmsg = "unrecoverable error occured. Try again later.";

        # User took too long to login and the original request token is stale.
        } elsif ($status == WK_ERR_REQUEST_TOKEN_STALE) {
            $errmsg = "you took too long to login.";

        # User's password has expired and we don't have anywhere to send them
        # to change it.
        } elsif ($status == WK_ERR_CREDS_EXPIRED) {
            $errmsg = "your password has expired.";

        # Like WK_ERR_UNRECOVERABLE_ERROR, but indicates the error most likely
        # is due to the webauth server making the request, so stop but display
        # a different error messaage.
        } elsif ($status == WK_ERR_WEBAUTH_SERVER_ERROR) {
            $errmsg = "there is most likely a configuration problem with"
                . " the server that redirected you. Please contact its"
                . " administrator.";
        }

        # Display the error page.
        print STDERR "WebKDC::make_request_token_request failed with"
            . " $errmsg: $error\n" if $self->param ('logging');
        $self->template_params ({err_webkdc => 1});
        $self->template_params ({err_msg => $errmsg});
        return $self->print_error_page;
    }
}

##############################################################################
# Actions to various requests
##############################################################################

# Main index, to log users in or display the login page if they are required
# to enter login data.
# Pages: multifactor page (success + multifactor required)
#        login page (login failure)
#        password reset page (success + password expired)
#        confirm page (success + no multifactor + confirm required)
#        redirect to base site (success + no multifactor + no confirm)
#        error page (some critical failure)
#        internal service error page (could not call template)
sub index : StartRunmode {
    my ($self) = @_;

    my $q = $self->query;
    my $req = $self->{request};
    my $resp = $self->{response};
    my ($status, $error);

    # Test for lack of a request token, cookies not being enabled, or
    # sending passwords over a non-POST method.  If found, these will
    # internally handle the error pages, so we stop processing this
    # request.
    my $page;
    return $page if defined ($page = $self->error_no_request_token);
    return $page if defined ($page = $self->error_if_no_cookies);
    return $page if defined ($page = $self->error_password_no_post);

    # Set up all WebKDC parameters, including tokens, proxy tokens, and
    # IP and trace information.
    my %cart = CGI::Cookie->fetch;
    $status = $self->setup_kdc_request (%cart);

    # Pass the information along to the WebKDC and get the response.
    if (!$status) {
        ($status, $error) = WebKDC::make_request_token_request ($req, $resp);
    }

    # Parse the result from the WebKDC and get the login cancel information if
    # any.
    # FIXME: (The login cancel stuff is oddly placed here, like it was added
    # as an afterthought, and should probably be handled in a cleaner
    # fashion.)
    $self->get_login_cancel_url;

    # parse_uri returns 1 on failure to parse the return_url.
    if ($status == WK_SUCCESS && $self->parse_uri) {
        $status = WK_ERR_WEBAUTH_SERVER_ERROR;
    }

    # Now, display the appropriate page.  If $status is WK_SUCCESS, we have a
    # successful authentication (by way of proxy token or username/password
    # login).  Otherwise, process the error.
    # Auth branch on "WebKDC return status" 1A
    if ($status == WK_SUCCESS) {
        if (defined (&WebKDC::Config::record_login)) {
            WebKDC::Config::record_login ($resp->subject);
        }
        if ($q->param ('password')) {
            $self->register_auth ($req->request_token, $resp->subject);
        }

        print STDERR "WebKDC::make_request_token_request success\n"
            if $self->param ('debug');
        return $self->print_confirm_page;
    } else {
        return $self->handle_login_error ($status, $error);
    }
}

# Process a request to log out of the page.  This won't be called by anything
# else by WebLogin, only by the logout page directly.
# Pages: logout template (success)
#        service error page (failure building template)
sub logout : Runmode {
    my ($self) = @_;
    my $q = $self->query;
    my %cookies = CGI::Cookie->fetch;
    my $ca;
    my %params;

    # Locate any webauth_wpt cookies and blow them away, by setting the same
    # cookie again with a null value and an expiration date in the past.
    for my $key (sort keys %cookies) {
        if ($key =~ /^webauth_wpt/) {
            my ($name) = split ('=', $cookies{$key});
            push (@$ca, $q->cookie (-name => $name, -value => $EXPIRED_COOKIE,
                                    -expires => '-1d', -secure => 1));
         }
    }

    $self->header_props (-type => 'text/html', -Pragma => 'no-cache',
                         -Cache_Control => 'no-cache, no-store');
    if ($ca) {
        $params{cookies_flag} = 1;
        $self->header_add (-cookie => $ca);
    }

    my $pages = $self->param ('pages');
    my $pagename = $pages->{logout};
    my $content = $self->tt_process ($pagename, \%params);
    if ($content) {
        return $content;
    } else {
        return $self->print_error_fatal ('could not process login template');
    }
}

# Handle the user attempting to change current password, whether from the
# user's own request or a force-change on password expiration.
# Pages: password change screen (failure)
#        login screen (success on force-change)
#        confirm page (success on user deciding to change)
sub pwchange : Runmode {
    my ($self) = @_;

    # Set up all WebKDC parameters, including tokens, proxy tokens, and
    # REMOTE_USER parameters.
    my %cart = CGI::Cookie->fetch;
    my $status = $self->setup_kdc_request (%cart);

    my $q = $self->query;
    my $req = $self->{request};
    my $resp = $self->{response};

    # Cases we might encounter:
    # * Expired password -- login.fcgi creates a changepw cred token and
    #   sends us here.
    # * Password going to expire soon -- login.fcgi creates a changpw cred
    #   token and gives a button to send us here.
    # * User choice -- User comes here on their own, needing to enter username
    #   and password

    # Check to see if this is our first visit and simply show the change page
    # if so (skipping checks for missing fields).
    if (!$self->query->param ('changepw')) {
        return $self->print_pwchange_page ($req->request_token,
                                           $req->service_token);
    }

    # Test to make sure that all required fields are filled out.
    my $page;
    return $page if defined ($page = $self->error_invalid_pwchange_fields);
    return $page if defined ($page = $self->error_if_no_cookies);
    return $page if defined ($page = $self->error_password_no_post);

    # Attempt password change via krb5_change_password API.
    my $error = '';
    if ($status == WK_SUCCESS) {
        ($status, $error) = $self->change_user_password;
    }

    # We've successfully changed the password.  Depending on if we were sent
    # by an expired password, either pass along to the normal page or give a
    # confirm screen.
    if ($status == WK_SUCCESS) {

        # Expired password -- drop back into the normal process flow.
        # 2A
        if ($self->query->param ('expired')
            and $self->query->param ('expired') == 1) {

            # Get the right script name and password.
            $self->param ('script_name', $WebKDC::Config::LOGIN_URL);
            my $newpass = $self->query->param ('new_passwd1');
            $self->query->param ('password', $newpass);

            # Move back into the main page flow now.
            return $self->forward ('index');

        # We weren't sent by expired password -- just print a confirm.
        # 2B
        } else {
            return $self->print_pwchange_confirm_page;
        }

    # Check if the user's old password was wrong.
    } elsif ($status == WK_ERR_LOGIN_FAILED) {
        $self->template_params ({error => 1});
        $self->template_params ({err_loginfailed => 1});
        return $self->print_pwchange_page ($self->query->param ('RT'),
                                           $self->query->param ('ST'));

    # The password change failed for some reason.  Display the password change
    # page again, with the error template variable filled in.  Heimdal, when
    # using an external password strength checking program, adds a prefix to
    # the error message that users don't care about, so strip that out.
    } else {
        $error =~ s/^Kerberos error \((.*)\)/$1/;
        $error =~ s/^password change failed for \S+: \(\d+\) //;
        $error =~ s/External password quality program failed: //;
        $self->template_params ({error => 1});
        $self->template_params ({err_pwchange => 1});
        $self->template_params ({err_msg => $error});
        return $self->print_pwchange_page ($self->query->param ('RT'),
                                           $self->query->param ('ST'));
    }
}

# Handle displaying the password change screen when the user has explicitly
# requested that screen.  This variation will not be called by anything else
# in the pages, only by the pwchange script directly.
# Pages: password change screen (success)
sub pwchange_display : Runmode {
    my ($self) = @_;

    # Set up all WebKDC parameters, including tokens, proxy tokens, and
    # REMOTE_USER parameters.
    my %cart = CGI::Cookie->fetch;
    $self->setup_kdc_request (%cart);

    my $req = $self->{request};
    my $resp = $self->{response};
    return $self->print_pwchange_page ($req->request_token,
                                       $req->service_token);
}

# Handle a multifactor login request, or request to send an SMS for
# multifactor login.
# Pages: Multifactor page (failure to login or sending an SMS)
#        Passes to normal login process (success)
sub multifactor : Runmode {
    my ($self) = @_;
    my $q = $self->query;

    # The username should always be set here.
    if (!defined ($q->param ('username'))) {
        $self->template_params ({err_confirm => 1});
        return $self->print_error_page;
    }

    # Set up all WebKDC parameters, including tokens, proxy tokens, and
    # REMOTE_USER parameters.
    my %cart = CGI::Cookie->fetch;
    my $status = $self->setup_kdc_request (%cart);

    if ($q->param ('otp')) {
        my $req = $self->{request};
        my $resp = $self->{response};
        $req->user ($q->param ('username'));
        my $error;
        if ($status == 0) {
            ($status, $error)
                = WebKDC::make_request_token_request ($req, $resp);
        }

        if ($status == WK_SUCCESS) {
            print STDERR "WebKDC::make_request_token_request success\n"
                if $self->param ('debug');
            $self->register_auth ($req->request_token, $resp->subject);
            return $self->print_confirm_page;
        } elsif ($status == WK_ERR_MULTIFACTOR_REQUIRED) {
            print STDERR "additional multifactor required\n"
                if $self->param ('logging');
        } elsif ($status == WK_ERR_LOGIN_FAILED) {
            print STDERR "multifactor failed: $error ($status)\n"
                if $self->param ('logging');
            $self->template_params ({err_multifactor_invalid => 1});
            $self->register_auth_fail ($req->user);
        } elsif ($status == WK_ERR_LOGIN_REJECTED) {
            my $message = $resp->user_message;
            print STDERR "multifactor rejected: $error ($status): $message\n"
                if $self->param ('logging');
            $self->register_auth_fail ($req->user);
        } else {
            # Hopefully this is close enough that we can just use the default
            # error handling code.
            return $self->handle_login_error ($status, $error);
        }
    } else {
        $self->template_params ({err_multifactor_missing => 1});
    }

    if ($q->param ('multifactor_sentauth')) {
        $self->template_params ({multifactor_sentauth => 1});
    }
    my $req = $self->{request};
    return $self->print_multifactor_page ($req->request_token,
                                          $req->service_token);
}

# Handle a request to send a multifactor authentication token somewhere via
# program.  The normal example case would be to fire off a command that sends
# an OTP via SMS.
# Pages: Multifactor page on success
#        Error page on any failure
sub multifactor_sendauth : Runmode {
    my ($self) = @_;
    my $q = $self->query;

    # The username should always be set here.
    if (!defined ($q->param ('username'))) {
        $self->template_params ({err_confirm => 1});
        return $self->print_error_page;
    }

    # Set up all WebKDC parameters, including tokens, proxy tokens, and
    # REMOTE_USER parameters.
    my %cart = CGI::Cookie->fetch;
    my $status = $self->setup_kdc_request (%cart);

    # Check for replays and authentication rate limiting
    if ($status == WK_ERR_AUTH_REPLAY) {
        $self->template_params ({err_replay => 1});
        return $self->print_error_page;
    } elsif ($status == WK_ERR_AUTH_LOCKOUT) {
        $self->template_params ({err_lockout => 1});
        return $self->print_error_page;
    }

    # Error if we don't have the setup configured.
    if (!$WebKDC::Config::MULTIFACTOR_SERVER
        || !$WebKDC::Config::MULTIFACTOR_COMMAND) {

        print STDERR "multifactor_sendauth failed due to no server "
            . "configured\n" if $self->param ('logging');

        my $errmsg = "unrecoverable error occured. Try again later.";
        $self->template_params ({err_webkdc => 1});
        $self->template_params ({err_msg => $errmsg});
        return $self->print_error_page;

    } else {

        # Send the remctl command, switching tgts out beforehand.
        my $username = $q->param ('username');
        my @cmd = split (' ', $WebKDC::Config::MULTIFACTOR_COMMAND);
        local $ENV{KRB5CCNAME} = $WebKDC::Config::MULTIFACTOR_TGT;
        my $result = Net::Remctl::remctl ($WebKDC::Config::MULTIFACTOR_SERVER,
                                          $WebKDC::Config::MULTIFACTOR_PORT,
                                          $WebKDC::Config::MULTIFACTOR_PRINC,
                                          @cmd, $username);

        if ($result->error) {
            print STDERR "multifactor_sendauth failed to run program: " .
                $result->error . "\n" if $self->param ('logging');
            $self->template_params ({err_sendauth => 1});
            return $self->print_error_page;
        } elsif ($result->status != 0) {
            print STDERR "multifactor_sendauth failed to run program: " .
                $result->stderr . "\n" if $self->param ('logging');
            $self->template_params ({err_sendauth => 1});
            return $self->print_error_page;
        } else {
            $self->template_params ({multifactor_sentauth => 1});
            my $req = $self->{request};
            return $self->print_multifactor_page ($req->request_token,
                                                  $req->service_token);
        }
    }
}

# Handle the request from the user to change the authorization identity,
# called from the confirm screen.  For this case, we'll need to resubmit the
# authentication request and get a new id or proxy token.
# Pages: confirm screen
sub edit_authz_identity : Runmode {
    my ($self) = @_;

    # Set up all WebKDC parameters, including tokens, proxy tokens, and
    # REMOTE_USER parameters.
    my %cart = CGI::Cookie->fetch;
    my $status = $self->setup_kdc_request (%cart);

    # Resubmit the authentication request.
    my $req = $self->{request};
    my $resp = $self->{response};
    my $error;
    if ($status == 0) {
        ($status, $error) = WebKDC::make_request_token_request ($req, $resp);
    }
    if ($status == WK_SUCCESS) {
        print STDERR "WebKDC::make_request_token_request success\n"
            if $self->param ('debug');
        return $self->print_confirm_page;
    } else {
        return $self->handle_login_error ($status, $error);
    }
}

# Handle the request from the user to change their REMOTE_USER setting, called
# from the confirm screen.  All of the actual 'action' here is performed by
# the confirm screen sending itself with a cookie set or cleared.
# Pages: confirm screen
sub edit_remoteuser : Runmode {
    my ($self) = @_;

    # Set up all WebKDC parameters, including tokens, proxy tokens, and
    # REMOTE_USER parameters.
    my %cart = CGI::Cookie->fetch;
    $self->setup_kdc_request (%cart);

    my $q = $self->query;
    return $self->redisplay_confirm_page;
}

##############################################################################
# Documentation
##############################################################################

1;

__END__

=for stopwords
WebAuth WebLogin CGI login API Allbery CPT FastCGI PAGETYPE SMS SPNEGO SSL
URI USERNAME login logins memcached redisplay remctl username keyring
post-login logout OTP WebKDC multifactor

=head1 NAME

WebLogin - Central login service for the WebAuth authentication system

=head1 SYNOPSIS

    use WebLogin;

    my $weblogin = WebLogin->new (PARAMS => { pages => \%pages },
                                  QUERY  => $q);
    $weblogin->run;

=head1 DESCRIPTION

The WebLogin module implements a CGI service using the CGI::Application
framework that provides central login services for the WebAuth
authentication system.  For its entry points and constructor options, see
L<CGI::Application/"Instance Script Methods">.

This module is normally only called from the F<login.fcgi>, F<logout.fcgi>,
and F<pwchange.cgi> scripts that come with WebAuth and comprise, with this
module, the WebLogin service.  It is not currently designed to be used by
any other scripts and does not currently have a documented API.

=head1 FUNCTIONS

=over 4

=item setup

Overridden CGI::Application setup function.  This is used for all
initialization of data needed for our WebLogin object.  It sets various
defaults, sets up our Template Toolkit options, creates memcached
caches, and other needed setup items to prepare.

=item cgiapp_prerun

Overridden CGI::Application function that is called before the
processing of each individual query.  This does further setup that's
meant to be query-specific, since we're potentially being wrapped up in
FastCGI or other methods that will cache the WebLogin object.

This includes clearing any parameters or template parameters from
previous runs, creating fresh objects for handling current query and
responses, and storing other query-specific data.

=item krb5_escape (PRINCIPAL)

Escape special characters in a principal name to match the escaping done
by krb5_unparse_name.  Returns the escaped principal name.

=item fix_token (TOKEN)

Encode a token for URL usage.

=item expire_cookie (NAME, SECURE)

Create and return a CGI::Cookie object that will expire an existing
cookie.  The cookie has the given NAME set, and includes the given flag
as to whether or not it uses SSL.

=item is_factor_set

Uses the cookies set on the WebKDC::WebResponse object to determine if
we have a factor token passed back from the WebKDC.  Returns 1 if so, 0
if not.

=item template_params (SETTINGS_REF)

Interface used to wrap up and save various parameters that we are
storing to later be used in the template files.  Takes a hashref to
settings we wish to add/override, and returns the ending hashref of all
current parameters.

=item get_pagename (PAGETYPE)

Takes the type of page we want, then returns the file name of the
template that is used to display that page type.

=item print_headers (ARGS_REF)

Sets the headers for a page.  This handles setting or removing any
cookies, then setting the headers.  If a return URL was set, add a
redirect to that URL into the headers.

=item pretty_return_uri (URI)

Takes a URI object and uses it to create a 'pretty' return URI, one
that's more readable by users for display on the configuration page.
Returns a string containing that URI.

=item parse_uri

Parses the return URL from the web response and either sets the pretty
URI (via petty_return_uri) or flags an error to the template if there
was something wrong with the URL.

=item token_rights

Parses the F<token.acl> file, using that to return an arrayref of the
credentials that the requesting WAS is permitted to obtain.  This is
used in cases where a specific WAS might have access to request
delegated credentials.

=item get_login_cancel_url

Checks to see if there is a login canceled token, and if so, sets
template parameters to offer a login canceled URL with that token.

=item print_login_page

View for the user login page.  This is the view that allows a user to
attempt to login, offering fields for username and password, possibly a
URL for remote user authentication, and any errors from previous failed
logins.

=item print_error_page

View for the generic error page.  This will pass along any previously
set error types for the template, and make sure that the error page
itself isn't cached.

=item print_error_fatal

View for a fatal error.  This is something normally only used on an
error to print out a template, meant as an emergency fallback to
display something when things are very messed up.

=item print_confirm_page

View for the confirmation page post-login.  This potentially includes a
password expiration warning, a warning for expiring device factor
cookies, and a notice for delegated credentials.  If none of those are
set, then we may (on WebKDC::Config settings) bypass the confirmation
page entirely and just send a redirect to the login destination.

=item redisplay_confirm_page

View to redisplay the confirmation page after a change in the
REMOTE_USER cookie.  This is a much more simple version of
print_confirm_page, as it doesn't have to do most of the checking for
warnings and whether or not to bypass the page.

=item print_pwchange_page

View to print out the password change page.  Pass along any needed user
information, such as their login information and any change password
token.

=item print_pwchange_confirm_page

View to print out a confirmation after a successful password change.
This is only accessed when the user is going to the password change
page via the URL just for that, rather than as a part of the normal
login flow.

=item print_multifactor_page

View to print out a page prompting the user to enter their multifactor
one-time password.  We pass along user information, the factors
needed for login, and the factors the user has.

=item print_remuser_redirect

Redirect a user to the REMOTE_USER enabled login URL.  This passes the
request token and service token on to the URL, then returns it as a
redirect page for CGI::Application to print.

=item add_generic_proxy_token (ARGS_REFERENCE)

Create and add a generic token to the set of tokens passed to the
WebKDC via the web request.  Read the ARGS_REFERENCE for any
non-default arguments we wish to create the proxy token with, then
create a new WebAuth::Token::WebKDCProxy object.  Encode it with the
keyring and add it to the proxy cookies on the web request.

=item add_kerberos_proxy_token

Create a proxy token using forwarded Kerberos credentials and pass into
the web request.

=item add_remuser_token

Create a proxy token with the REMOTE_USER identity and pass into the
web request.  This does validation against the REMOTE_USER setting,
then passes along to add_generic_proxy_token if it passes our
requirements.

=item add_changepw_token

Create a kadmin/changepw token using the username and password of a
user after successful login.  This will create a ticket, put it into a
WebAuth::Token::Cred object, and use the keyring to encode it.  The
token is passed back as the CPT parameter on the WebLogin object.
Returns 1 on success.

=item change_user_password

Attempt to change a user's password using a previously created change
password token.  Validate that the token is correct for the given user,
then attempt to change the user's password, returning a status and any
exception objects that may have been created during failures.

=item error_if_no_cookies

Tests to make sure that cookies are enabled in the user's browser.  If
a test cookie is not set, we reload the page with an attempt to set
that cookie and a flag showing that we're making the attempt.  If we
find the flag set and no cookie, then the user does not have cookies
set, and we display an error page.

=item error_password_no_post

Tests to make sure that if a password was sent, the request method was
POST.  This is done in order to avoid the password potentially showing
up in referrer strings sent to a remote site.  If the method was not
POST, we display an error page.

=item error_no_request_token

Tests to make sure that we have a request token and service token
defined in the submitted CGI query.  If not, we will display an error
page.

=item error_invalid_pwchange_fields

Tests the requirements for a password change request page to be
successfully entered.  This does not actually try to change the
password or check that it is successful, but only checks to make sure
that the user has entered all of the needed data.  If not, we will
display the password change page again, with error flags for the
missing or incorrect fields.

=item is_replay (RT)

Checks against memcached to see if the given request token has been
recently used, in order to detect a replay attack.  Returns 1 if the
request token was found.

=item is_rate_limited (USERNAME)

Checks against memcached to see if the given user has exceeded a
certain number of failed logins.  Returns 1 if the user has exceeded
the number (set in WebKDC::Config).

=item register_auth (RT, USERNAME)

Registers a successful authentication for the given user in memcached,
with the request token for the authentication.  This is used to detect
replay attacks.

=item register_auth_fail (USERNAME)

Registers a failed authentication for the given user in memcached.  This
is used for rate limiting users on failed logins.

=item setup_kdc_request (COOKIES)

Takes the WebKDC::WebRequest object already created, and fills that
object with data from the user/browser.  This includes current cookies
passed to us, and also any relevant data sent via the CGI query.  The
latter can include username and password, for two examples.

Returns the status from the request.  This is usually WK_SUCCESS as we
are not actually contacting the WebKDC at this point, but can be error
statuses in cases such as the user not filling in their username, or
if replay or rate limited checks were triggered.

=item handle_login_error (STATUS, ERROR)

This is a catch-all handler for any error during the normal user login
process.  This uses the given error status to decide what needs to be
done to handle this error case, often simply printing out a screen to
request additional information or the user to re-enter correct
information.  In some cases, this will have to throw up an
unrecoverable error page that the user can do nothing with.

=item index

The default run mode, handling the basic attempt to log in, whether via
plain username and password, SPNEGO, or other method.

This is called if no other run mode is set by the main login URL, or on
any regular failure to successfully log in (such as invalid password).

=item logout

Run mode to handle a request by the user to log out, blowing away all
proxy cookies.

This is only called via the logout URL.

=item pwchange()

Run mode to handle an attempt by the user to change their current
password.  This handles the attempt to change the user password, either
passing the user on to the confirmation page or bringing the user back
to this page on a problem with changing the password.

This is called by either the user clicking a link from the confirm page
warning that their password is soon to expire, or by the user being
forced to here after logging in with an expired password.

=item pwchange_display

Run mode to handle a direct access to the password change display
screen.

This is called only by the user visiting the password change URL from
outside the normal program flow.

=item multifactor

Run mode to handle an attempted multifactor login.  The username and
one-time password are passed to the WebKDC in order to validate whether or
not there was a successful login, and the user is then sent to either the
confirm page on success, or the multifactor page again on failure.

This is called from the multifactor entry screen, when the user submits
their one-time password.

=item multifactor_sendauth

Run mode to handle the request from a user to send a multifactor
authentication token somewhere via a remctl command.  The command
itself is configured in WebKDC::Config.  The normal case would be
sending out a OTP over SMS to a user.

This is called from the multifactor entry screen, in the case of a user
having a multifactor method that requires the user be sent a token.

=item edit_authz_identity

Run mode to handle the request from a user to change their authorization
identity.

This is called from the config screen.

=item edit_remoteuser

Run mode to handle the request from a user to change their REMOTE_USER
setting.

This is called from the config screen.

=back

=head1 AUTHORS

Roland Schemers, Russ Allbery <eagle@eyrie.org>, and Jon Robertson
<jonrober@stanford.edu>.

=head1 SEE ALSO

WebAuth(3), WebKDC(3), WebKDC::Config(3)

This module is part of WebAuth.  The current version is available from
L<http://webauth.stanford.edu/>.

=cut