1 2 3 4NETWORK WORKING GROUP N. Williams 5Internet-Draft Sun 6Expires: April 19, 2006 October 16, 2005 7 8 9 Guide to the GSS-APIv3 10 draft-ietf-kitten-gssapi-v3-guide-to-01.txt 11 12Status of this Memo 13 14 By submitting this Internet-Draft, each author represents that any 15 applicable patent or other IPR claims of which he or she is aware 16 have been or will be disclosed, and any of which he or she becomes 17 aware will be disclosed, in accordance with Section 6 of BCP 79. 18 19 Internet-Drafts are working documents of the Internet Engineering 20 Task Force (IETF), its areas, and its working groups. Note that 21 other groups may also distribute working documents as Internet- 22 Drafts. 23 24 Internet-Drafts are draft documents valid for a maximum of six months 25 and may be updated, replaced, or obsoleted by other documents at any 26 time. It is inappropriate to use Internet-Drafts as reference 27 material or to cite them other than as "work in progress." 28 29 The list of current Internet-Drafts can be accessed at 30 http://www.ietf.org/ietf/1id-abstracts.txt. 31 32 The list of Internet-Draft Shadow Directories can be accessed at 33 http://www.ietf.org/shadow.html. 34 35 This Internet-Draft will expire on April 19, 2006. 36 37Copyright Notice 38 39 Copyright (C) The Internet Society (2005). 40 41Abstract 42 43 Extensions to the GSS-APIv2 are needed for a number of reasons. This 44 documents describes the extensions being proposed, the resons, 45 possible future directions, and portability, IANA and security 46 considerations. This document does not define any protocol or 47 interface and is purely informational. 48 49 50 51 52 53 54 55Williams Expires April 19, 2006 [Page 1] 56 57Internet-Draft Guide to the GSS-APIv3 October 2005 58 59 60Table of Contents 61 62 1. Conventions used in this document . . . . . . . . . . . . . . 3 63 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 64 3. A Pseudo-Mechanism OID for the GSS-API Itself . . . . . . . . 6 65 4. Mechanism Attribute Inquiry Facilities . . . . . . . . . . . . 7 66 5. Security Context Extensibility Extensions . . . . . . . . . . 8 67 6. Credential Extensibility Extensions . . . . . . . . . . . . . 9 68 7. Credential Export/Import . . . . . . . . . . . . . . . . . . . 10 69 8. GSS_Store_cred() . . . . . . . . . . . . . . . . . . . . . . . 11 70 9. Pseudo-Mechanism Stacking . . . . . . . . . . . . . . . . . . 12 71 10. Naming Extensions . . . . . . . . . . . . . . . . . . . . . . 13 72 11. Additional Name Types . . . . . . . . . . . . . . . . . . . . 14 73 12. GSS_Pseudo_random() . . . . . . . . . . . . . . . . . . . . . 15 74 13. Channel Bindings Specifications . . . . . . . . . . . . . . . 16 75 14. Semantic and Miscallaneous Extensions . . . . . . . . . . . . 17 76 15. Portability Considerations . . . . . . . . . . . . . . . . . . 18 77 16. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 78 17. Security Considerations . . . . . . . . . . . . . . . . . . . 20 79 18. Normative . . . . . . . . . . . . . . . . . . . . . . . . . . 20 80 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 21 81 Intellectual Property and Copyright Statements . . . . . . . . 22 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 111Williams Expires April 19, 2006 [Page 2] 112 113Internet-Draft Guide to the GSS-APIv3 October 2005 114 115 1161. Conventions used in this document 117 118 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 119 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 120 document are to be interpreted as described in [RFC2119]. 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 167Williams Expires April 19, 2006 [Page 3] 168 169Internet-Draft Guide to the GSS-APIv3 October 2005 170 171 1722. Introduction 173 174 [NOTE: the references section is current fairly empty; the various 175 KITTEN WG work items will be added to this I-D in a subsequent 176 revision.] 177 178 Since the advent of the GSS-APIv2 it has come to be used in a number 179 of Internet (and other) protocols and a number of implementations 180 exist. In that time implementors and protocol designers have come to 181 understand both, the GSS-API's strengths, and its shortcommings; we 182 believe now that a number of extensions to the GSS-API are needed. 183 Here these proposed extensions, forming what we may call the GSS-API 184 version 3, are described at a high-level.; 185 186 Some of these extensions are intended to facilitate further 187 extensions, so that further major revisions to the GSS-API may not be 188 necessary. Others are intended to fill voids in the the GSS-APIv2. 189 190 The extensions being proposed are: 191 192 A pseudo-mechanism OID for the GSS-API itself 193 194 Mechanism attribute inquiry facilities 195 196 Security context extensibility extensions 197 198 Credential extensibility extensions 199 200 Credential export/import 201 202 GSS_Store_cred(), for making delegated credentials available for 203 acquisition 204 205 Pseudo-mechanism stacking 206 207 Naming extensions, to facilitate authorization by identifiers 208 other than names 209 210 Additional name types, specifically domain-based naming 211 212 A pseudo-random function interface 213 214 Channel bindings specifications 215 216 Semantic extensions relating to thread- and/or fork-safety 217 218 [Have I missed anything? I have a feeling I have. Re-keying?] 219 220 221 222 223Williams Expires April 19, 2006 [Page 4] 224 225Internet-Draft Guide to the GSS-APIv3 October 2005 226 227 228 ... 229 230 Additionally, because we foresee future minor extensions, including, 231 specifically, extensions which may impact the various namespaces 232 associated with APIs (symbol names, constant values, class names, 233 etc...) we also propose the establishment of IANA registries for 234 these namespaces. 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 279Williams Expires April 19, 2006 [Page 5] 280 281Internet-Draft Guide to the GSS-APIv3 October 2005 282 283 2843. A Pseudo-Mechanism OID for the GSS-API Itself 285 286 A mechanism OID is assigned to identify and refer to the GSS-API 287 iself. This is necessary to enable the use of extended inquiry 288 interfaces to inquire about features of a GSS-API implementation 289 specifically, apart from actual mechanisms. 290 291 But also, this OID is needed for better error handling, so that minor 292 status codes produced in generic contexts that lack a mechanism OID 293 can be distinguished from minor status codes for a "default" 294 mechanism and properly displayed. 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 335Williams Expires April 19, 2006 [Page 6] 336 337Internet-Draft Guide to the GSS-APIv3 October 2005 338 339 3404. Mechanism Attribute Inquiry Facilities 341 342 In the course of designing a pseudo-mechanism stacking facility, as 343 well as while considering the impact of all of these extensions on 344 portability, a need for interfaces through which to discover or 345 inquire by features provided by GSS-API mechanisms was discovered. 346 347 The proposed mechanism attribute inquiry interfaces consist of: 348 349 GSS_Inquire_mech_attrs_for_mech() 350 351 GSS_Indicate_mechs_by_mech_attrs() 352 353 GSS_Display_mech_attr() 354 355 These extensions facilitate portability by allowing GSS-APIv3 356 applications to discover the features provided by a given 357 implementation of the GSS-API or any mechanisms. These extensions 358 are also useful in facilitating stackable pseudo-mechanisms. 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 391Williams Expires April 19, 2006 [Page 7] 392 393Internet-Draft Guide to the GSS-APIv3 October 2005 394 395 3965. Security Context Extensibility Extensions 397 398 In order to facilitate future security context options we introduce a 399 GSS_Create_sec_context() interface that creates a security context 400 object, for use with extensions and with GSS_Init_sec_context(), 401 GSS_Accept_sec_context(), and GSS_Inquire_sec_context(). Such 402 security contexts are in a non-established state until they are 403 established through the use of GSS_Init_sec_context() or 404 GSS_Accept_sec_context(). 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 447Williams Expires April 19, 2006 [Page 8] 448 449Internet-Draft Guide to the GSS-APIv3 October 2005 450 451 4526. Credential Extensibility Extensions 453 454 In order to facilitate future extensions to GSS credentials we 455 introduce a GSS_Create_credential(), similar to 456 GSS_Create_sec_context(), interface that creates an "empty" 457 credential. 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 503Williams Expires April 19, 2006 [Page 9] 504 505Internet-Draft Guide to the GSS-APIv3 October 2005 506 507 5087. Credential Export/Import 509 510 To allow for passing of credentials between different "session 511 contexts," between different hosts, or for storage of post-dated 512 credentials, we introduce a credential export/import facility, much 513 like the security context export/import facility of the GSS-APIv2. 514 515 Together with credential extensibility and other extensions this 516 facility may allow for: 517 518 Credential delegation at any time 519 520 Post-dated credentials, and storage of the such for subsequent 521 use. 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 559Williams Expires April 19, 2006 [Page 10] 560 561Internet-Draft Guide to the GSS-APIv3 October 2005 562 563 5648. GSS_Store_cred() 565 566 This extension fills a void in the GSS-APIv2 where delegated 567 credentials could not be used except in the context of the same 568 process that received them. With this extension acceptor 569 applications can now make delegated credentials available for use, 570 with GSS_Acquire_cred() et. al., in other process contexts. 571 572 [Manipulation of "credential stores" is (may be?) out of scope for 573 this document.] 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 615Williams Expires April 19, 2006 [Page 11] 616 617Internet-Draft Guide to the GSS-APIv3 October 2005 618 619 6209. Pseudo-Mechanism Stacking 621 622 A number of pseudo-mechanisms are being proposed which are designed 623 to "stack" atop other mechanisms. The possiblities are many, 624 including: a compression mechanism, a perfect forward security 625 mechanism, an many others. 626 627 The GSS-APIv2 only had concrete mechanisms and one pseudo-mechanism 628 (SPNEGO) available. With this proposal the mechanism taxonomy is 629 quite expanded: 630 631 Concrete mechanisms (e.g., the Kerberos V mechanism) 632 633 Composite mechanisms (a concrete mechanism composed with one or 634 more stackable pseudo-mechanisms) 635 636 Stackable pseudo-mechanisms 637 638 Other pseudo-mechanisms (e.g., SPNEGO, the GSS-API itself) 639 640 Although composed mechanisms may be made available for use by GSS- 641 APIv2 applications without any further extensions, use of stackable 642 pseudo-mechanisms can complicate mechanism negotiation; additionally, 643 discovery of mechanisms appropriate for use in one or another context 644 would require hard-coding information about them in GSS-APIv2 645 applications. Extensions to the GSS-APIv2 could facilitate use of 646 composite. 647 648 The mechanism attribute inquiry facilities, together with the 649 forllowing additional interfaces, provide for a complete interface to 650 mechanism composition and for managing the complexity of mechanism 651 negotiation: 652 653 GSS_Compose_oid() 654 655 GSS_Decompose_oid() 656 657 GSS_Release_oid() 658 659 GSS_Indicate_negotiable_mechs() 660 661 GSS_Negotiate_mechs() 662 663 664 665 666 667 668 669 670 671Williams Expires April 19, 2006 [Page 12] 672 673Internet-Draft Guide to the GSS-APIv3 October 2005 674 675 67610. Naming Extensions 677 678 Some applications make use of exported names, as produced by 679 GSS_Export_name(), to create/manage/evaluate access control lists; we 680 call this name-based authorization. 681 682 Exported names typically encode names that are meant for display to 683 humans, not internal identifiers. 684 685 In practice this creates a number of problems. E.g., the referential 686 integrity of such access control lists is hard to maintain as 687 principals are added, removed, renamed or old principal names reused. 688 689 Additionally, some mechanisms may lack a notion of a "canonical" name 690 for some or all of their principals. Such mechanisms cannot be used 691 by applications that rely on name-based authorization. 692 693 <Describe the proposed extensions in this area.> 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 727Williams Expires April 19, 2006 [Page 13] 728 729Internet-Draft Guide to the GSS-APIv3 October 2005 730 731 73211. Additional Name Types 733 734 <Decribe domain-based names and the need for them.> 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 783Williams Expires April 19, 2006 [Page 14] 784 785Internet-Draft Guide to the GSS-APIv3 October 2005 786 787 78812. GSS_Pseudo_random() 789 790 <Decribe GSS_Pseudo_random() and the need for it.> 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 839Williams Expires April 19, 2006 [Page 15] 840 841Internet-Draft Guide to the GSS-APIv3 October 2005 842 843 84413. Channel Bindings Specifications 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 895Williams Expires April 19, 2006 [Page 16] 896 897Internet-Draft Guide to the GSS-APIv3 October 2005 898 899 90014. Semantic and Miscallaneous Extensions 901 902 The GSS-APIv2 specifications say nothing about the thread-safety, 903 much less the fork-safety, of the GSS-API. Thread-safety and fork- 904 safety are, after all, platform- and/or language-specific matters. 905 But as support for multi-threading spreads the matter of thread- 906 safety cannot be avoided. The matter of fork-safety is specific to 907 platforms that provide a "fork()" function, or similar. 908 909 <describe the GSS-APIv3's thread-safety requirements> 910 911 <reference the portability considerations section> 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 951Williams Expires April 19, 2006 [Page 17] 952 953Internet-Draft Guide to the GSS-APIv3 October 2005 954 955 95615. Portability Considerations 957 958 The potential for additional generic, mechanism-specific, language 959 binding-specific and, most importantly, semantic extensions to the 960 GSS-APIv3 may create application portability problems. The mechanism 961 attribute inquiry facilities of the GSS-APIv3 and the pseudo- 962 mechanism OID for the GSS-API itself double as a run-time facility 963 for discovery of feature availability. Run-time feature discovery 964 facilities, in turn, can be used at application build-time as well by 965 building small applications to display the available features. 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 1007Williams Expires April 19, 2006 [Page 18] 1008 1009Internet-Draft Guide to the GSS-APIv3 October 2005 1010 1011 101216. IANA Considerations 1013 1014 <Describe the namespace issues associated with future minor 1015 extensions to the GSS-APIv3 and the IANA registries to be created to 1016 cope with them.> 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 1063Williams Expires April 19, 2006 [Page 19] 1064 1065Internet-Draft Guide to the GSS-APIv3 October 2005 1066 1067 106817. Security Considerations 1069 1070 <...> 1071 107218. Normative 1073 1074 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1075 Requirement Levels", BCP 14, RFC 2119, March 1997. 1076 1077 [RFC2743] Linn, J., "Generic Security Service Application Program 1078 Interface Version 2, Update 1", RFC 2743, January 2000. 1079 1080 [RFC2744] Wray, J., "Generic Security Service API Version 2 : 1081 C-bindings", RFC 2744, January 2000. 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 1119Williams Expires April 19, 2006 [Page 20] 1120 1121Internet-Draft Guide to the GSS-APIv3 October 2005 1122 1123 1124Author's Address 1125 1126 Nicolas Williams 1127 Sun Microsystems 1128 5300 Riata Trace Ct 1129 Austin, TX 78727 1130 US 1131 1132 Email: Nicolas.Williams@sun.com 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 1175Williams Expires April 19, 2006 [Page 21] 1176 1177Internet-Draft Guide to the GSS-APIv3 October 2005 1178 1179 1180Intellectual Property Statement 1181 1182 The IETF takes no position regarding the validity or scope of any 1183 Intellectual Property Rights or other rights that might be claimed to 1184 pertain to the implementation or use of the technology described in 1185 this document or the extent to which any license under such rights 1186 might or might not be available; nor does it represent that it has 1187 made any independent effort to identify any such rights. 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Please address the information to the IETF at 1202 ietf-ipr@ietf.org. 1203 1204 1205Disclaimer of Validity 1206 1207 This document and the information contained herein are provided on an 1208 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 1209 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET 1210 ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, 1211 INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE 1212 INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 1213 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 1214 1215 1216Copyright Statement 1217 1218 Copyright (C) The Internet Society (2005). This document is subject 1219 to the rights, licenses and restrictions contained in BCP 78, and 1220 except as set forth therein, the authors retain all their rights. 1221 1222 1223Acknowledgment 1224 1225 Funding for the RFC Editor function is currently provided by the 1226 Internet Society. 1227 1228 1229 1230 1231Williams Expires April 19, 2006 [Page 22] 1232 1233 1234