From 4bfd864f10b68b71482b35c818559068ef8d5797 Mon Sep 17 00:00:00 2001 From: Thomas Voss Date: Wed, 27 Nov 2024 20:54:24 +0100 Subject: doc: Add RFC documents --- doc/rfc/rfc5588.txt | 395 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 395 insertions(+) create mode 100644 doc/rfc/rfc5588.txt (limited to 'doc/rfc/rfc5588.txt') diff --git a/doc/rfc/rfc5588.txt b/doc/rfc/rfc5588.txt new file mode 100644 index 0000000..ee2a13e --- /dev/null +++ b/doc/rfc/rfc5588.txt @@ -0,0 +1,395 @@ + + + + + + +Network Working Group N. Williams +Request for Comments: 5588 Sun +Category: Standards Track July 2009 + + + Generic Security Service Application Program Interface (GSS-API) + Extension for Storing Delegated Credentials + +Abstract + + This document defines a new function for the Generic Security Service + Application Program Interface (GSS-API), which allows applications to + store delegated (and other) credentials in the implicit GSS-API + credential store. This is needed for GSS-API applications to use + delegated credentials as they would use other credentials. + +Status of This Memo + + This document specifies an Internet standards track protocol for the + Internet community, and requests discussion and suggestions for + improvements. Please refer to the current edition of the "Internet + Official Protocol Standards" (STD 1) for the standardization state + and status of this protocol. Distribution of this memo is unlimited. + +Copyright Notice + + Copyright (c) 2009 IETF Trust and the persons identified as the + document authors. All rights reserved. + + This document is subject to BCP 78 and the IETF Trust's Legal + Provisions Relating to IETF Documents in effect on the date of + publication of this document (http://trustee.ietf.org/license-info). + Please review these documents carefully, as they describe your rights + and restrictions with respect to this document. + +Table of Contents + + 1. Introduction ....................................................2 + 2. Conventions Used in This Document ...............................3 + 3. GSS_Store_cred() ................................................3 + 4. C-Bindings ......................................................5 + 5. Examples ........................................................6 + 6. Security Considerations .........................................6 + 7. Normative References ............................................7 + + + + + + + +Williams Standards Track [Page 1] + +RFC 5588 GSS_Store_cred() July 2009 + + +1. Introduction + + The GSS-API [RFC2743] clearly assumes that credentials exist in an + implicit store whence they can be acquired using GSS_Acquire_cred() + and GSS_Add_cred() or through use of the default credential. + Multiple credential stores may exist on a given host, but only one + store may be accessed by GSS_Acquire_cred() and GSS_Add_cred() at any + given time. + + This assumption can be seen in Sections 1.1.1.2 and 1.1.1.3 of + [RFC2743] as well as in Section 3.5 of [RFC2744]. + + Applications may be able to change the credential store from which + credentials can be acquired, either by changing user contexts (where + the applications have the privilege to do so) or by other means + (where a user may have multiple credential stores). + + Some GSS-API acceptor applications always change user contexts, after + accepting a GSS-API security context and making appropriate + authorization checks, to the user context corresponding to the + initiator principal name or to a context requested by the initiator. + The means by which credential stores are managed are generally beyond + the scope of the GSS-API. + + In the case of delegated credential handles however, such credentials + do not exist in the acceptor's credential store or in the credential + stores of the user contexts to which the acceptor application might + change. The GSS-API provides no mechanism by which delegated + credential handles can be made available for acquisition through + GSS_Acquire_cred()/GSS_Add_cred(). The GSS-API also does not provide + any credential import/export interfaces like the GSS-API context + import/export interfaces. + + Thus, acceptors are limited to making only direct use of delegated + credential handles and only with GSS_Init_sec_context(), + GSS_Inquire_cred*(), and GSS_Release_cred(). This limitation is + particularly onerous on Unix systems where a call to exec() to + replace the process image obliterates any delegated credentials + handle that may exist in that process. + + In order to make delegated credentials generally as useful as + credentials that can be acquired with GSS_Acquire_cred() and + GSS_Add_cred(), a primitive is needed that allows storing of + credentials in the implicit credential store. We call this primitive + "GSS_Store_cred()". + + + + + + +Williams Standards Track [Page 2] + +RFC 5588 GSS_Store_cred() July 2009 + + +2. Conventions Used in This Document + + The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", + "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this + document are to be interpreted as described in [RFC2119]. + +3. GSS_Store_cred() + + Inputs: + + o input_cred_handle CREDENTIAL HANDLE, -- credential to store; MUST + NOT be GSS_C_NO_CREDENTIAL. + + o cred_usage INTEGER -- 0=INITIATE-AND-ACCEPT, 1=INITIATE-ONLY, + 2=ACCEPT-ONLY. + + o desired_mech_element OBJECT IDENTIFIER, -- if GSS_C_NULL_OID, then + store all the elements of the input_cred_handle, otherwise, store + only the element of the corresponding mechanism. + + o overwrite_cred BOOLEAN, -- if TRUE, replace any credential for the + same principal in the credential store. + + o default_cred BOOLEAN -- advisory input; if TRUE, make the stored + credential available as the default credential (for acquisition + with GSS_C_NO_NAME as the desired name or for use as + GSS_C_NO_CREDENTIAL). + + Outputs: + + o major_status INTEGER. + + o minor_status INTEGER. + + o mech_elements_stored SET OF OBJECT IDENTIFIER, -- the set of + mechanism OIDs for which credential elements were successfully + stored. + + o cred_usage_stored INTEGER -- like cred_usage, but indicates what + kind of credential was stored (useful when the cred_usage input + parameter is set to INITIATE-AND-ACCEPT). + + Return major_status codes: + + o GSS_S_COMPLETE indicates that the credentials were successfully + stored. + + + + + +Williams Standards Track [Page 3] + +RFC 5588 GSS_Store_cred() July 2009 + + + o GSS_S_CREDENTIALS_EXPIRED indicates that the input credentials had + expired or expired before they could be stored. + + o GSS_S_NO_CRED indicates that no input credentials were given. + + o GSS_S_UNAVAILABLE indicates that the credential store is not + available. + + o GSS_S_DUPLICATE_ELEMENT indicates that an element of the input + credential could not be stored because a credential for the same + principal exists in the current credential store and the + overwrite_cred input argument was FALSE. + + o GSS_S_FAILURE indicates that the credential could not be stored + for some other reason. The minor status code may provide more + information if a non-GSS_C_NULL_OID desired_mech_element was + given. + + GSS_Store_cred() is used to store, in the current credential store, a + given credential that has either been acquired from a different + credential store or been accepted as a delegated credential. + + Specific mechanism elements of a credential can be stored one at a + time by specifying a non-GSS_C_NULL_OID mechanism OID as the + desired_mech_element input argument; in which case, the minor status + output SHOULD have a mechanism-specific value when the major status + is not GSS_S_COMPLETE. + + The initiator, acceptor, or both usages of the input credential may + be stored as per the cred_usage input argument. + + The credential elements that were actually stored, when the major + status is GSS_S_COMPLETE, are indicated through the cred_usage_stored + and mech_elements_stored function outputs. + + If credentials already exist in the current store for the principal + of the input_cred_handle, then those credentials are not replaced + with the input credentials unless the overwrite_cred input argument + is TRUE. + + In the GSS-API, the default credential can be used by using + GSS_C_NO_CREDENTIAL or a CREDENTIAL handle acquired by calling + GSS_Acquire_cred() or GSS_Add_cred() with the desired_name input set + to GSS_C_NO_NAME. + + If the default_cred input argument is TRUE, and the input credential + can be successfully stored, then the input credential SHOULD be + stored as the default credential (see above). + + + +Williams Standards Track [Page 4] + +RFC 5588 GSS_Store_cred() July 2009 + + + If the current credential store has no default credential (see + above), then the implementation MAY make the stored credentials + available as the default credential regardless of the value of the + default_cred input argument. + +4. C-Bindings + + The C-Bindings for GSS_Store_cred() make use of types from and are + designed based on the style of the GSS-APIv2 C-Bindings [RFC2744]. + + OM_uint32 gss_store_cred( + OM_uint32 *minor_status, + gss_cred_id_t input_cred_handle, + gss_cred_usage_t cred_usage, + const gss_OID desired_mech, + OM_uint32 overwrite_cred, + OM_uint32 default_cred, + gss_OID_set *elements_stored, + gss_cred_usage_t *cred_usage_stored) + + Figure 1 + + The two boolean arguments, 'overwrite_cred' and 'default_cred', are + typed as OM_uint32; 0 corresponds to FALSE, non-zero values + correspond to TRUE. + + + + + + + + + + + + + + + + + + + + + + + + + + +Williams Standards Track [Page 5] + +RFC 5588 GSS_Store_cred() July 2009 + + +5. Examples + + The intended usage of GSS_Store_cred() is to make delegated + credentials available to child processes of GSS-API acceptor + applications. Example pseudo-code: + + /* + * + * + * <"requested_username" is a username derived from the + * initiator name or explicitly requested by the initiator + * application.> + */ + ... + + if (authorize_gss_client(src_name, requested_username)) { + /* + * For Unix-type platforms this may mean calling setuid() and + * it may or may not also mean setting/unsetting such + * environment variables as KRB5CCNAME and what not -- all + * OS-specific details. + */ + if (change_user_context(requested_username)) + (void) gss_store_cred(&minor_status, deleg_cred, + GSS_C_INITIATE, actual_mech, + 0, 1, NULL, NULL); + } + else ... + } + else ... + +6. Security Considerations + + Acceptor applications MUST only store delegated credentials into + appropriate credential stores and only after proper authorization of + the authenticated initiator principal to the requested service(s). + + Acceptor applications that have no use for delegated credentials MUST + release them (such acceptor applications that use the GSS-API C- + Bindings may simply provide a NULL value for the + delegated_cred_handle argument to gss_accept_sec_context()). + + + + + + + + +Williams Standards Track [Page 6] + +RFC 5588 GSS_Store_cred() July 2009 + + +7. Normative References + + [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate + Requirement Levels", BCP 14, RFC 2119, March 1997. + + [RFC2743] Linn, J., "Generic Security Service Application Program + Interface Version 2, Update 1", RFC 2743, January 2000. + + [RFC2744] Wray, J., "Generic Security Service API Version 2 : + C-bindings", RFC 2744, January 2000. + +Author's Address + + Nicolas Williams + Sun Microsystems + 5300 Riata Trace Ct + Austin, TX 78727 + US + + EMail: Nicolas.Williams@sun.com + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Williams Standards Track [Page 7] + -- cgit v1.2.3