1 2 3NETWORK WORKING GROUP N. Williams 4Internet-Draft Sun 5Expires: July 26, 2005 January 25, 2005 6 7 8 Guide to the GSS-APIv3 9 draft-ietf-kitten-gssapi-v3-guide-to-00.txt 10 11Status of this Memo 12 13 By submitting this Internet-Draft, I certify that any applicable 14 patent or other IPR claims of which I am aware have been disclosed, 15 and any of which I become aware will be disclosed, in accordance with 16 RFC 3668. 17 18 Internet-Drafts are working documents of the Internet Engineering 19 Task Force (IETF), its areas, and its working groups. Note that 20 other groups may also distribute working documents as 21 Internet-Drafts. 22 23 Internet-Drafts are draft documents valid for a maximum of six months 24 and may be updated, replaced, or obsoleted by other documents at any 25 time. It is inappropriate to use Internet-Drafts as reference 26 material or to cite them other than as "work in progress." 27 28 The list of current Internet-Drafts can be accessed at 29 http://www.ietf.org/ietf/1id-abstracts.txt. 30 31 The list of Internet-Draft Shadow Directories can be accessed at 32 http://www.ietf.org/shadow.html. 33 34 This Internet-Draft will expire on July 26, 2005. 35 36Copyright Notice 37 38 Copyright (C) The Internet Society (2005). All Rights Reserved. 39 40Abstract 41 42 Extensions to the GSS-APIv2 are needed for a number of reasons. This 43 documents describes the extensions being proposed, the resons, 44 possible future directions, and portability, IANA and security 45 considerations. This document does not define any protocol or 46 interface and is purely informational. 47 48 49 50 51 52 53 54 55Williams Expires July 26, 2005 [Page 1] 56 57Internet-Draft Guide to the GSS-APIv3 January 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 . . . . . . . . 5 65 4. Mechanism Attribute Inquiry Facilities . . . . . . . . . . . . 6 66 5. Security Context Extensibility Extensions . . . . . . . . . . 7 67 6. Credential Extensibility Extensions . . . . . . . . . . . . . 8 68 7. Credential Export/Import . . . . . . . . . . . . . . . . . . . 9 69 8. GSS_Store_cred() . . . . . . . . . . . . . . . . . . . . . . . 10 70 9. Pseudo-Mechanism Stacking . . . . . . . . . . . . . . . . . . 11 71 10. Naming Extensions . . . . . . . . . . . . . . . . . . . . . . 12 72 11. Additional Name Types . . . . . . . . . . . . . . . . . . . . 13 73 12. GSS_Pseudo_random() . . . . . . . . . . . . . . . . . . . . . 14 74 13. Channel Bindings Specifications . . . . . . . . . . . . . . . 15 75 14. Semantic and Miscallaneous Extensions . . . . . . . . . . . . 16 76 15. Portability Considerations . . . . . . . . . . . . . . . . . . 17 77 16. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 78 17. Security Considerations . . . . . . . . . . . . . . . . . . . 19 79 18. Normative . . . . . . . . . . . . . . . . . . . . . . . . . . 19 80 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 19 81 Intellectual Property and Copyright Statements . . . . . . . . 20 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 July 26, 2005 [Page 2] 112 113Internet-Draft Guide to the GSS-APIv3 January 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 July 26, 2005 [Page 3] 168 169Internet-Draft Guide to the GSS-APIv3 January 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 A pseudo-mechanism OID for the GSS-API itself 192 Mechanism attribute inquiry facilities 193 Security context extensibility extensions 194 Credential extensibility extensions 195 Credential export/import 196 GSS_Store_cred(), for making delegated credentials available for 197 acquisition 198 Pseudo-mechanism stacking 199 Naming extensions, to facilitate authorization by identifiers 200 other than names 201 Additional name types, specifically domain-based naming 202 A pseudo-random function interface 203 Channel bindings specifications 204 Semantic extensions relating to thread- and/or fork-safety 205 [Have I missed anything? I have a feeling I have. Re-keying?] 206 ... 207 208 Additionally, because we foresee future minor extensions, including, 209 specifically, extensions which may impact the various namespaces 210 associated with APIs (symbol names, constant values, class names, 211 etc...) we also propose the establishment of IANA registries for 212 these namespaces. 213 214 215 216 217 218 219 220 221 222 223Williams Expires July 26, 2005 [Page 4] 224 225Internet-Draft Guide to the GSS-APIv3 January 2005 226 227 2283. A Pseudo-Mechanism OID for the GSS-API Itself 229 230 A mechanism OID is assigned to identify and refer to the GSS-API 231 iself. This is necessary to enable the use of extended inquiry 232 interfaces to inquire about features of a GSS-API implementation 233 specifically, apart from actual mechanisms. 234 235 But also, this OID is needed for better error handling, so that minor 236 status codes produced in generic contexts that lack a mechanism OID 237 can be distinguished from minor status codes for a "default" 238 mechanism and properly displayed. 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 July 26, 2005 [Page 5] 280 281Internet-Draft Guide to the GSS-APIv3 January 2005 282 283 2844. Mechanism Attribute Inquiry Facilities 285 286 In the course of designing a pseudo-mechanism stacking facility, as 287 well as while considering the impact of all of these extensions on 288 portability, a need for interfaces through which to discover or 289 inquire by features provided by GSS-API mechanisms was discovered. 290 291 The proposed mechanism attribute inquiry interfaces consist of: 292 GSS_Inquire_mech_attrs_for_mech() 293 GSS_Indicate_mechs_by_mech_attrs() 294 GSS_Display_mech_attr() 295 296 These extensions facilitate portability by allowing GSS-APIv3 297 applications to discover the features provided by a given 298 implementation of the GSS-API or any mechanisms. These extensions 299 are also useful in facilitating stackable pseudo-mechanisms. 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 July 26, 2005 [Page 6] 336 337Internet-Draft Guide to the GSS-APIv3 January 2005 338 339 3405. Security Context Extensibility Extensions 341 342 In order to facilitate future security context options we introduce a 343 GSS_Create_sec_context() interface that creates a security context 344 object, for use with extensions and with GSS_Init_sec_context(), 345 GSS_Accept_sec_context(), and GSS_Inquire_sec_context(). Such 346 security contexts are in a non-established state until they are 347 established through the use of GSS_Init_sec_context() or 348 GSS_Accept_sec_context(). 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 391Williams Expires July 26, 2005 [Page 7] 392 393Internet-Draft Guide to the GSS-APIv3 January 2005 394 395 3966. Credential Extensibility Extensions 397 398 In order to facilitate future extensions to GSS credentials we 399 introduce a GSS_Create_credential(), similar to 400 GSS_Create_sec_context(), interface that creates an "empty" 401 credential. 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 447Williams Expires July 26, 2005 [Page 8] 448 449Internet-Draft Guide to the GSS-APIv3 January 2005 450 451 4527. Credential Export/Import 453 454 To allow for passing of credentials between different "session 455 contexts," between different hosts, or for storage of post-dated 456 credentials, we introduce a credential export/import facility, much 457 like the security context export/import facility of the GSS-APIv2. 458 459 Together with credential extensibility and other extensions this 460 facility may allow for: 461 Credential delegation at any time 462 Post-dated credentials, and storage of the such for subsequent 463 use. 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 July 26, 2005 [Page 9] 504 505Internet-Draft Guide to the GSS-APIv3 January 2005 506 507 5088. GSS_Store_cred() 509 510 This extension fills a void in the GSS-APIv2 where delegated 511 credentials could not be used except in the context of the same 512 process that received them. With this extension acceptor 513 applications can now make delegated credentials available for use, 514 with GSS_Acquire_cred() et. al., in other process contexts. 515 516 [Manipulation of "credential stores" is (may be?) out of scope for 517 this document.] 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 559Williams Expires July 26, 2005 [Page 10] 560 561Internet-Draft Guide to the GSS-APIv3 January 2005 562 563 5649. Pseudo-Mechanism Stacking 565 566 A number of pseudo-mechanisms are being proposed which are designed 567 to "stack" atop other mechanisms. The possiblities are many, 568 including: a compression mechanism, a perfect forward security 569 mechanism, an many others. 570 571 The GSS-APIv2 only had concrete mechanisms and one pseudo-mechanism 572 (SPNEGO) available. With this proposal the mechanism taxonomy is 573 quite expanded: 574 Concrete mechanisms (e.g., the Kerberos V mechanism) 575 Composite mechanisms (a concrete mechanism composed with one or 576 more stackable pseudo-mechanisms) 577 Stackable pseudo-mechanisms 578 Other pseudo-mechanisms (e.g., SPNEGO, the GSS-API itself) 579 580 Although composed mechanisms may be made available for use by 581 GSS-APIv2 applications without any further extensions, use of 582 stackable pseudo-mechanisms can complicate mechanism negotiation; 583 additionally, discovery of mechanisms appropriate for use in one or 584 another context would require hard-coding information about them in 585 GSS-APIv2 applications. Extensions to the GSS-APIv2 could facilitate 586 use of composite. 587 588 The mechanism attribute inquiry facilities, together with the 589 forllowing additional interfaces, provide for a complete interface to 590 mechanism composition and for managing the complexity of mechanism 591 negotiation: 592 GSS_Compose_oid() 593 GSS_Decompose_oid() 594 GSS_Release_oid() 595 GSS_Indicate_negotiable_mechs() 596 GSS_Negotiate_mechs() 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615Williams Expires July 26, 2005 [Page 11] 616 617Internet-Draft Guide to the GSS-APIv3 January 2005 618 619 62010. Naming Extensions 621 622 Some applications make use of exported names, as produced by 623 GSS_Export_name(), to create/manage/evaluate access control lists; we 624 call this name-based authorization. 625 626 Exported names typically encode names that are meant for display to 627 humans, not internal identifiers. 628 629 In practice this creates a number of problems. E.g., the referential 630 integrity of such access control lists is hard to maintain as 631 principals are added, removed, renamed or old principal names reused. 632 633 Additionally, some mechanisms may lack a notion of a "canonical" name 634 for some or all of their principals. Such mechanisms cannot be used 635 by applications that rely on name-based authorization. 636 637 <Describe the proposed extensions in this area.> 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 671Williams Expires July 26, 2005 [Page 12] 672 673Internet-Draft Guide to the GSS-APIv3 January 2005 674 675 67611. Additional Name Types 677 678 <Decribe domain-based names and the need for them.> 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 727Williams Expires July 26, 2005 [Page 13] 728 729Internet-Draft Guide to the GSS-APIv3 January 2005 730 731 73212. GSS_Pseudo_random() 733 734 <Decribe GSS_Pseudo_random() and the need for it.> 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 July 26, 2005 [Page 14] 784 785Internet-Draft Guide to the GSS-APIv3 January 2005 786 787 78813. Channel Bindings Specifications 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 839Williams Expires July 26, 2005 [Page 15] 840 841Internet-Draft Guide to the GSS-APIv3 January 2005 842 843 84414. Semantic and Miscallaneous Extensions 845 846 The GSS-APIv2 specifications say nothing about the thread-safety, 847 much less the fork-safety, of the GSS-API. Thread-safety and 848 fork-safety are, after all, platform- and/or language-specific 849 matters. But as support for multi-threading spreads the matter of 850 thread-safety cannot be avoided. The matter of fork-safety is 851 specific to platforms that provide a "fork()" function, or similar. 852 853 <describe the GSS-APIv3's thread-safety requirements> 854 855 <reference the portability considerations section> 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 July 26, 2005 [Page 16] 896 897Internet-Draft Guide to the GSS-APIv3 January 2005 898 899 90015. Portability Considerations 901 902 The potential for additional generic, mechanism-specific, language 903 binding-specific and, most importantly, semantic extensions to the 904 GSS-APIv3 may create application portability problems. The mechanism 905 attribute inquiry facilities of the GSS-APIv3 and the 906 pseudo-mechanism OID for the GSS-API itself double as a run-time 907 facility for discovery of feature availability. Run-time feature 908 discovery facilities, in turn, can be used at application build-time 909 as well by building small applications to display the available 910 features. 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 951Williams Expires July 26, 2005 [Page 17] 952 953Internet-Draft Guide to the GSS-APIv3 January 2005 954 955 95616. IANA Considerations 957 958 <Describe the namespace issues associated with future minor 959 extensions to the GSS-APIv3 and the IANA registries to be created to 960 cope with them.> 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 1007Williams Expires July 26, 2005 [Page 18] 1008 1009Internet-Draft Guide to the GSS-APIv3 January 2005 1010 1011 101217. Security Considerations 1013 1014 <...> 1015 101618 Normative 1017 1018 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1019 Requirement Levels", BCP 14, RFC 2119, March 1997. 1020 1021 [RFC2743] Linn, J., "Generic Security Service Application Program 1022 Interface Version 2, Update 1", RFC 2743, January 2000. 1023 1024 [RFC2744] Wray, J., "Generic Security Service API Version 2 : 1025 C-bindings", RFC 2744, January 2000. 1026 1027 1028Author's Address 1029 1030 Nicolas Williams 1031 Sun Microsystems 1032 5300 Riata Trace Ct 1033 Austin, TX 78727 1034 US 1035 1036 EMail: Nicolas.Williams@sun.com 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 July 26, 2005 [Page 19] 1064 1065Internet-Draft Guide to the GSS-APIv3 January 2005 1066 1067 1068Intellectual Property Statement 1069 1070 The IETF takes no position regarding the validity or scope of any 1071 Intellectual Property Rights or other rights that might be claimed to 1072 pertain to the implementation or use of the technology described in 1073 this document or the extent to which any license under such rights 1074 might or might not be available; nor does it represent that it has 1075 made any independent effort to identify any such rights. Information 1076 on the procedures with respect to rights in RFC documents can be 1077 found in BCP 78 and BCP 79. 1078 1079 Copies of IPR disclosures made to the IETF Secretariat and any 1080 assurances of licenses to be made available, or the result of an 1081 attempt made to obtain a general license or permission for the use of 1082 such proprietary rights by implementers or users of this 1083 specification can be obtained from the IETF on-line IPR repository at 1084 http://www.ietf.org/ipr. 1085 1086 The IETF invites any interested party to bring to its attention any 1087 copyrights, patents or patent applications, or other proprietary 1088 rights that may cover technology that may be required to implement 1089 this standard. Please address the information to the IETF at 1090 ietf-ipr@ietf.org. 1091 1092 1093Disclaimer of Validity 1094 1095 This document and the information contained herein are provided on an 1096 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 1097 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET 1098 ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, 1099 INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE 1100 INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 1101 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 1102 1103 1104Copyright Statement 1105 1106 Copyright (C) The Internet Society (2005). This document is subject 1107 to the rights, licenses and restrictions contained in BCP 78, and 1108 except as set forth therein, the authors retain all their rights. 1109 1110 1111Acknowledgment 1112 1113 Funding for the RFC Editor function is currently provided by the 1114 Internet Society. 1115 1116 1117 1118 1119Williams Expires July 26, 2005 [Page 20] 1120 1121 1122