Add kx509 client and revamp kx509 service
This commit adds support for kx509 in libkrb5, and revamps the KDC's
kx509 service (fixing bugs, adding features).
Of note is that kx509 is attempted optimistically by the client, with
the certificate and private key stored in the ccache, and optionally in
an external PEM or DER file.
NOTE: We do not optimistically use kx509 in krb5_cc_store_cred() if the
ccache is a MEMORY ccache so we don't generate a key when
accepting a GSS context with a delegated credential.
kx509 protocol issues to be fixed in an upcoming commit:
- no proof of possession (this is mostly not too bad, but we'll want to
fix it by using CSRs)
- no algorithm agility (only plain RSA is supported)
- very limited (no way to request any options in regards to the
requested cert)
- error codes are not very useful
Things we're adding in this commit:
- libkrb5 kx509 client
- automatic kx509 usage hooked in via krb5_cc_store_cred() of start TGT
- per-realm templates on the KDC side
- per-realm issuer certificates
- send error messages on the KDC side
(this is essential to avoid client-side timeouts on error)
- authenticate as many error messages
- add a protocol probe feature so we can avoid generating a
keypair if the service is not enabled
(once we add support for ECC algorithms we won't need this
anymore; the issue is that RSA keygen is slow)
- support for different types of client principals, not just username:
- host-based service and domain-based service, each with its own
template set per-{realm, service} or per-service
(the idea is to support issuance of server certificates too, not
just client/user certs)
- more complete support for SAN types
- tests (including that PKINIT->kx509->PKINIT works, which makes it
possible to have "delegation" of PKIX credentials by just delegating
Kerberos credentials)
- document the protocol in lib/krb5/kx509.c
Future work:
- add option for longer-ticket-lifetime service certs
- add support for ECDSA, and some day for ed25519 and ed448
- reuse private key when running kinit
(this will require rethinking how we trigger optimistic kx509
usage)
- HDB lookup for:
- optional revocation check (not strictly necessary)
- adding to certificates those SANs listed in HDB
- hostname aliases (dNSName SANs)
- rfc822Name (email)
- XMPP SANs
- id-pkinit-san (a user could have aliases too)
- support username wild-card A RRs, ala OSKT/krb5_admin
i.e., if a host/f.q.d.n principal asks for a certificate for
some service at some-label.f.q.d.n, then issue it
(this is not needed at OSKT sites because OSKT already
supports keying such service principals, which means kx509
will issue certificates for them, however, it would be nice
to be able to have this independent of OSKT)
(a better way to do this would be to integrate more of OSKT
into Heimdal proper)
- a kx509 command, or heimtools kx509 subcommand for explicitly
attempting use of the kx509 protocol (as opposed to implicit, as is
done in kinit via krb5_cc_store_cred() magic right now)
Issues:
- optimistically trying kx509 on start realm TGT store -> timeout issues!
- newer KDCs will return errors because of this commit; older ones
will not, which causes timouts
- need a separate timeout setting for kx509 for optimistic case
- need a [realm] config item and DNS SRV RR lookup for whether a
realm is expected to support kx509 service
This commit is contained in:
Nicolas Williams
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doc/standardisation/rfc6717.txt
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Independent Submission H. Hotz
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Request for Comments: 6717 Jet Propulsion Lab, Caltech
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Category: Informational R. Allbery
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ISSN: 2070-1721 Stanford University
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August 2012
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kx509 Kerberized Certificate Issuance Protocol in Use in 2012
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Abstract
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This document describes a protocol, called kx509, for using Kerberos
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tickets to acquire X.509 certificates. These certificates may be
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used for many of the same purposes as X.509 certificates acquired by
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other means, but if a Kerberos infrastructure already exists, then
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the overhead of using kx509 may be much less.
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While not standardized, this protocol is already in use at several
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large organizations, and certificates issued with this protocol are
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recognized by the International Grid Trust Federation.
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Status of This Memo
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This document is not an Internet Standards Track specification; it is
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published for informational purposes.
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This is a contribution to the RFC Series, independently of any other
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RFC stream. The RFC Editor has chosen to publish this document at
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its discretion and makes no statement about its value for
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implementation or deployment. Documents approved for publication by
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the RFC Editor are not a candidate for any level of Internet
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Standard; see Section 2 of RFC 5741.
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Information about the current status of this document, any errata,
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and how to provide feedback on it may be obtained at
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http://www.rfc-editor.org/info/rfc6717.
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Copyright Notice
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Copyright (c) 2012 IETF Trust and the persons identified as the
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document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
|
||||
Provisions Relating to IETF Documents
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||||
(http://trustee.ietf.org/license-info) in effect on the date of
|
||||
publication of this document. Please review these documents
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carefully, as they describe your rights and restrictions with respect
|
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to this document.
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Hotz & Allbery Informational [Page 1]
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RFC 6717 kx509 August 2012
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Table of Contents
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1. Introduction ....................................................2
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1.1. Requirements Language ......................................3
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2. Protocol Data ...................................................3
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2.1. Request Packet .............................................3
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2.2. Reply Packet ...............................................4
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3. Protocol Operation ..............................................7
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4. Acknowledgements ................................................8
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5. IANA Considerations .............................................8
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6. Security Considerations .........................................9
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7. References .....................................................10
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7.1. Normative References ......................................10
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7.2. Informative References ....................................10
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Appendix A. Certificate Caching and Deployment Considerations ....12
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Appendix B. Historic Extensions ..................................12
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Appendix C. Example Exchange .....................................12
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1. Introduction
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The two primary ways of providing cryptographically secure
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identification on the Internet are Kerberos tickets [RFC4120] and
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X.509 [RFC5280] [X.509] certificates.
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In practical IT infrastructure where both are in use, it's highly
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desirable to deploy their support in a way that guarantees they both
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authoritatively refer to the same entities. There is already a
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widely adopted standard for using X.509 certificates to acquire
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corresponding Kerberos tickets called Public Key Cryptography for
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Initial Authentication in Kerberos (PKINIT) [RFC4556]. This document
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describes the kx509 protocol for supporting the symmetric operation
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of acquiring X.509 certificates using Kerberos tickets.
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Preparing and reviewing this document exposed a number of issues that
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are discussed in the security considerations. Unfortunately, some of
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them can only be addressed with an incompatible upgrade to this
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protocol. The IETF's Kerberos working group has an expected work
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item to address these issues.
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The International Grid Trust Federation [IGTF] supports the use of
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Short Lived Credential Services [SLCS] as a means to authenticate for
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resource usage based on other, native identity stores that an
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organization maintains. X.509 certificates issued using the kx509
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protocol based on a Kerberos identity is one of the recognized
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credential services. The certificate profile for that use is outside
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the scope of this RFC but is described in [GRID-prof].
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Hotz & Allbery Informational [Page 2]
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RFC 6717 kx509 August 2012
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In normal operation, kx509 can be used after a Kerberos ticket-
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granting-ticket (TGT) is acquired, which is most likely during user
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login. First, the client generates an RSA public/private key pair.
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Next, using the Kerberos ticket-granting-ticket, it acquires a
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Kerberos service ticket for the KCA (Kerberized Certificate
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Authority) and uses this to send the public half of its key pair.
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The KCA will decrypt the service ticket, verify the integrity of the
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incoming packet, determine the identity of the user, and use the
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session key to send back a corresponding X.509 certificate.
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1.1. Requirements Language
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The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
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"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
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document are to be interpreted as described in RFC 2119 [RFC2119].
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2. Protocol Data
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The protocol consists of a single request/reply exchange using UDP.
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Both the request and the reply packet begin with four bytes of
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version ID information, followed by a DER-encoded ASN.1 message. The
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first two bytes of the version ID are reserved. They MUST be set to
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zero when sent and SHOULD be ignored when received. The third and
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fourth bytes are the major and minor version numbers, respectively.
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The version of the protocol described in this document is designated
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2.0, so the first four bytes of the packet are 0, 0, 2, and 0.
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Incompatible variations of this protocol MUST use a different major
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version number.
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2.1. Request Packet
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The request consists of a version ID, followed by a DER-encoded ASN.1
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message containing a Kerberos AP-REQ, integrity check data on the
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request, and public key generated by the client. The ASN.1 encoding
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is:
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KX509Request ::= SEQUENCE {
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AP-REQ OCTET STRING,
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pk-hash OCTET STRING,
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pk-key OCTET STRING
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}
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The AP-REQ is as described in [RFC4120], Section 5.5.1.
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Hotz & Allbery Informational [Page 3]
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RFC 6717 kx509 August 2012
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The pk-hash is Hashed Message Authentication Code (HMAC) using SHA-1
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as the underlying hash. All 160 bits are sent. The key used is the
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Kerberos session key. The data to be hashed is the concatenation of
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the following:
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o 4-byte version ID at the beginning of the packet.
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o OCTET STRING of the AP-REQ.
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o OCTET STRING of the pk-key.
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The pk-key contains a public key. This key and its corresponding
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private key are generated by the client before contacting the server.
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Implementations of this protocol MUST support RSA keys, in which case
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the key is a DER-encoded RSAPublicKey as defined in [RFC3447],
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Section A.1.1, and then it is stored in this octet string in the
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request. Its encoding as an OCTET STRING starts with the 0x30 byte
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sequence at the beginning of a DER-encoded RSAPublicKey. Use of
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other public-key types is not defined.
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Appendix C shows an example request packet.
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2.2. Reply Packet
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The reply consists of a version ID, followed by a DER-encoded ASN.1
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message containing an error code, an optional authentication hash,
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optional certificate, and optional error text. The service SHOULD
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return replies of the same version as the request where possible.
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KX509Response ::= SEQUENCE {
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error-code[0] INTEGER DEFAULT 0,
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hash[1] OCTET STRING OPTIONAL,
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certificate[2] OCTET STRING OPTIONAL,
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e-text[3] VisibleString OPTIONAL
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}
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Although the format of the reply contains independently optional
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objects, the server MUST only generate replies with one of the
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following allowed combinations.
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+------------+------+-------------+--------+
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| | hash | certificate | |
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| error-code | hash | | e-text |
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| error-code | | | e-text |
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+------------+------+-------------+--------+
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Hotz & Allbery Informational [Page 4]
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RFC 6717 kx509 August 2012
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The first case is returned when the server successfully generates a
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certificate for the user. The certificate is a DER-encoded
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certificate as defined in [RFC5280], Appendix A, page 116. Its
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encoding as an OCTET STRING starts with the 0x30 byte sequence that
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is at the beginning of a DER-encoded certificate.
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The second case is returned when the server successfully
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authenticates the user and their key, but is unable for some other
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reason to generate a certificate.
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The third case MAY be returned if the server is unable to
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successfully authenticate the user and intends to return some
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unauthenticated information to the client.
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The hash on a response is computed using SHA-1 HMAC as for the
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request.
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The data that is hashed is the concatenation of the following things:
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o 4-byte version ID at the beginning of the packet.
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o DER representation of the error-code exclusive of the tag and
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length, if it is present.
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o OCTET STRING of the certificate, if it is present.
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o VisibleString representation of the e-text exclusive of the tag
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and length, if it is present.
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In other words, the hash is computed on the data in the fields that
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are present, exclusive of the overall ASN.1 wrapping.
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The e-text MAY be translated into other character sets for display
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purposes, but the hash is computed on the e-text in its VisibleString
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representation. If the e-text contains NUL characters, the client
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MAY ignore any part of the error message after the first NUL
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character for display purposes.
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As implied by the above table, if the reply does not contain a
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certificate, it MUST contain an error message and a non-zero error
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code. Conversely, if a certificate is returned, then the error-code
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MUST be zero. The server SHOULD use the DEFAULT encoding for a zero
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error-code value by omitting any explicit error-code from the reply.
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Hotz & Allbery Informational [Page 5]
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RFC 6717 kx509 August 2012
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The defined values for error-code are as follows:
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+------------+-----------------------------+------------------------+
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| error-code | Condition | Example |
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+------------+-----------------------------+------------------------+
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| 1 | Permanent problem with | Incompatible version |
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| | client request | |
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| 2 | Solvable problem with | Expired Kerberos |
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| | client request | credentials |
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| 3 | Temporary problem with | Packet loss |
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| | client request | |
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| 4 | Permanent problem with the | Internal |
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| | server | misconfiguration |
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| 5 | Temporary problem with the | Server overloaded |
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| | server | |
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+------------+-----------------------------+------------------------+
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If a client error is returned, the client SHOULD NOT retry the
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request unless some remedial action is first taken, although if
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error-code 3 is returned, the client MAY retry with other servers
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before giving up.
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If a server error is returned, it is RECOMMENDED that the client
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retry the request with a different server if one is known.
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Since all KCAs serving a Kerberos realm are intended to be
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equivalent, in accordance with Section 4.1.2.2 of [RFC5280], the
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certificates returned from different KCAs serving the same Kerberos
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realm MUST NOT contain duplicate serial numbers.
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This protocol and document do not address certificate verification or
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path construction. There are no provisions for returning any
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additional certificates that might be needed. Any application using
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a returned certificate must be configured independently to address
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these issues. An incompatible upgrade to this protocol will provide
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options to address this issue.
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The returned certificate MUST identify the Kerberos client principal
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from the AP-REQ in the original KX509Request in the subject of the
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certificate or in a subjectAltName extension. The identification
|
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MUST be unique within the organization's deployed infrastructure. It
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is RECOMMENDED that a subjectAltName extension be included of type
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id-pkinit-san as described in [RFC4556], Section 3.2.2. Note that
|
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the id-pkinit-san is simply a standard representation of a Kerberos
|
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principal and has no other implications with respect to PKINIT.
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Hotz & Allbery Informational [Page 6]
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RFC 6717 kx509 August 2012
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Other extensions MAY be added according to local policy.
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Appendix C shows an example reply packet.
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||||
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3. Protocol Operation
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Absent errors, the protocol consists of a single request, sent via
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UDP, and a single reply, also sent via UDP.
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||||
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||||
There is no special provision for requests or replies that exceed the
|
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allowable size of a UDP packet. Also, some implementations have
|
||||
imposed hard size limits that are smaller than a typical UDP MTU and
|
||||
will limit the use of extensions and the supportable key size. Even
|
||||
without hard limits, if the request or reply exceeds the MTU size of
|
||||
a UDP packet for the infrastructure in use, then the reliability of
|
||||
the exchange will decrease significantly.
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||||
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||||
For "normal" Kerberos AP-REQ structures, and "normal" X.509
|
||||
certificates, this is unlikely unless the Kerberos service ticket
|
||||
contains large amounts of authorization data. For this reason, it is
|
||||
RECOMMENDED that service tickets for the KCA be issued without
|
||||
authorization data. If the KCA performs authorization, it should do
|
||||
so by other means.
|
||||
|
||||
Before constructing the request, the client must know the canonical
|
||||
name(s) and port(s) of the server(s) to contact. It MAY determine
|
||||
them by looking up the service's SRV record as described in
|
||||
[RFC2782]. The entry to be used is _kca._udp._realm_, where _realm_
|
||||
is the Kerberos realm, used as part of the DNS name.
|
||||
|
||||
The client has to acquire a service ticket in order to construct the
|
||||
AP-REQ for the service. Conventionally, the Kerberos service
|
||||
principal name to use for this service has a first component of
|
||||
"kca_service". Absent local configuration or other external
|
||||
knowledge of the correct principal to use, the second and final
|
||||
component is conventionally the canonical name of the KCA server
|
||||
being contacted, and the realm of the principal is determined
|
||||
following normal Kerberos domain-to-realm mapping conventions, as
|
||||
discussed in [RFC4120], Section 1.3.
|
||||
|
||||
When the server receives a request, it MUST verify the following
|
||||
properties of the request before issuing a certificate:
|
||||
|
||||
o The AP-REQ can be decoded and is not expired.
|
||||
|
||||
o If the request uses cross-realm authentication, then it satisfies
|
||||
the requirements of local policy and [RFC4120], Sections 1.2 and
|
||||
2.7.
|
||||
|
||||
|
||||
|
||||
Hotz & Allbery Informational [Page 7]
|
||||
|
||||
RFC 6717 kx509 August 2012
|
||||
|
||||
|
||||
o The request's hash is valid.
|
||||
|
||||
The server SHOULD make other sanity checks, such as a minimum public
|
||||
key length, to the extent feasible.
|
||||
|
||||
The server MAY decline to respond to an erroneous request. If it
|
||||
does not receive a response, a client MAY retry its request, but the
|
||||
client SHOULD wait at least one second before doing so.
|
||||
|
||||
The client MUST verify any hash in the reply and MUST NOT use any
|
||||
certificate in a reply whose hash does not verify. The client MAY
|
||||
display the e-text if the hash is absent or does not verify but
|
||||
SHOULD indicate the message is not authenticated.
|
||||
|
||||
4. Acknowledgements
|
||||
|
||||
The original version of kx509 was implemented using Kerberos 4 at the
|
||||
University of Michigan and was nicely documented in [KX509]. Many
|
||||
thanks to them for their original work, as well as the subsequent
|
||||
updates.
|
||||
|
||||
While developing this document, important corrections and comments
|
||||
were provided by Jeffrey Altman and Love Hornquist Astrand. The
|
||||
following people also provided many helpful comments and corrections:
|
||||
Doug Engert, Jeffrey Hutzelman, Sam Hartman, Timothy J. Miller,
|
||||
Chaskiel Grundman, and Jim Schaad. Alan Sill provided the references
|
||||
to the International Grid Trust Federation and its acceptable
|
||||
credential services. Example network traffic was provided by Doug
|
||||
Engert, Marcus Watts, Matt Crawford, and Chaskiel Grundman from their
|
||||
deployments and was extremely useful for verifying the reality of
|
||||
this specification.
|
||||
|
||||
5. IANA Considerations
|
||||
|
||||
This service is conventionally run on UDP port 9878. IANA has
|
||||
registered that port in the Service Name and Transport Port Number
|
||||
Registry as follows:
|
||||
|
||||
Service Name: kca-service
|
||||
Transport Protocol: UDP
|
||||
Assignee: IESG <iesg@ietf.org>
|
||||
Contact: IETF Chair <chair@ietf.org>
|
||||
Description: The kx509 Kerberized Certificate Issuance
|
||||
Protocol in Use in 2012
|
||||
Reference: RFC 6717
|
||||
Port Number: 9878
|
||||
Assignment Notes: Historically, this service has been referred to
|
||||
as "kca_service", but this service name does
|
||||
|
||||
|
||||
|
||||
Hotz & Allbery Informational [Page 8]
|
||||
|
||||
RFC 6717 kx509 August 2012
|
||||
|
||||
|
||||
not meet the registry requirements.
|
||||
|
||||
The Generic Security Service Application Program Interface (GSS-API)
|
||||
/ Kerberos / Simple Authentication and Security Layer (SASL) service
|
||||
name currently in use for this protocol is "kca_service". This does
|
||||
not meet the naming requirements for IANA's GSS-API/Kerberos/SASL
|
||||
service name registry, so no registration has been requested. The
|
||||
conflict between the conventional service name and the registry rules
|
||||
is expected to be addressed in a future version of this protocol.
|
||||
Appropriate registrations will be requested at that time.
|
||||
|
||||
6. Security Considerations
|
||||
|
||||
The only encrypted information in the protocol is that used by
|
||||
Kerberos itself. The considerations for any Kerberized service apply
|
||||
here.
|
||||
|
||||
The public key in the request is sent in the clear and without any
|
||||
guarantees that the requester actually possesses the corresponding
|
||||
private key. Therefore, the only appropriate uses of the returned
|
||||
certificate are those where the identity of the requester is
|
||||
unimportant or the subsequent use independently guarantees that the
|
||||
user possesses the private key. This issue is expected to be
|
||||
addressed in a future version of this protocol.
|
||||
|
||||
For example, if the kx509-issued certificate is used for a digital
|
||||
signature in a way that does not independently demonstrate proof-of-
|
||||
possession of the private key, then an eavesdropper could request
|
||||
their own valid certificate via kx509 and claim to have originated
|
||||
material signed by the legitimate, original requester. [RFC4211],
|
||||
Appendix C, contains a more detailed discussion of why proof-of-
|
||||
possession is important.
|
||||
|
||||
An example that should be safe is initial client authentication with
|
||||
Transport Layer Security (TLS) [RFC5246] connections. If a client
|
||||
certificate is used, then a Certificate Verify message (Section 7.4.8
|
||||
of [RFC5246]) is added to the handshake exchange. It includes a
|
||||
signature of the handshake messages to that point. Those messages
|
||||
depend on data known only to the client and server ends of the
|
||||
specific connection, so computing the signature proves possession of
|
||||
the private key. This application was the original intended use case
|
||||
for kx509.
|
||||
|
||||
Some information, such as the public key and certificate, is
|
||||
transmitted in the clear but (as the name implies) is generally
|
||||
intended to be publicly available. However, its visibility could
|
||||
still raise privacy concerns. The hash is used to protect the
|
||||
integrity of this information.
|
||||
|
||||
|
||||
|
||||
Hotz & Allbery Informational [Page 9]
|
||||
|
||||
RFC 6717 kx509 August 2012
|
||||
|
||||
|
||||
The policies for issuing Kerberos tickets and X.509 certificates are
|
||||
usually expressed very differently. An implementation of this
|
||||
protocol should not provide a mechanism for bypassing ticket or
|
||||
certificate policies.
|
||||
|
||||
In particular, if the issued certificate can be used with PKINIT,
|
||||
this authentication loop SHOULD NOT bypass policy limits for either
|
||||
X.509 certificates or Kerberos tickets.
|
||||
|
||||
X.509 certificates are usually issued with considerably longer
|
||||
validity times than Kerberos tickets. Care should be taken that the
|
||||
issued certificate is not valid for longer than the intended policy
|
||||
should allow. Note that Section 3.2.3 of [RFC4556] REQUIRES that the
|
||||
lifetime of an issued ticket not exceed the lifetime of the
|
||||
predecessor certificate. By analogy, it is RECOMMENDED that the
|
||||
lifetime of an issued certificate not exceed the lifetime of the
|
||||
predecessor Kerberos ticket unless the implications with respect to
|
||||
local policy and supporting infrastructure are clearly understood and
|
||||
allow it.
|
||||
|
||||
7. References
|
||||
|
||||
7.1. Normative References
|
||||
|
||||
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
|
||||
Requirement Levels", BCP 14, RFC 2119, March 1997.
|
||||
|
||||
[RFC3447] Jonsson, J. and B. Kaliski, "Public-Key Cryptography
|
||||
Standards (PKCS) #1: RSA Cryptography Specifications
|
||||
Version 2.1", RFC 3447, February 2003.
|
||||
|
||||
[RFC4120] Neuman, C., Yu, T., Hartman, S., and K. Raeburn, "The
|
||||
Kerberos Network Authentication Service (V5)", RFC 4120,
|
||||
July 2005.
|
||||
|
||||
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
|
||||
Housley, R., and W. Polk, "Internet X.509 Public Key
|
||||
Infrastructure Certificate and Certificate Revocation
|
||||
List (CRL) Profile", RFC 5280, May 2008.
|
||||
|
||||
7.2. Informative References
|
||||
|
||||
[GRID-prof] "Grid Certificate Profile", March 2008,
|
||||
<http://www.ogf.org/documents/GFD.125.pdf>.
|
||||
|
||||
[IGTF] "The International Grid Trust Federation",
|
||||
<http://www.igtf.net/>.
|
||||
|
||||
|
||||
|
||||
|
||||
Hotz & Allbery Informational [Page 10]
|
||||
|
||||
RFC 6717 kx509 August 2012
|
||||
|
||||
|
||||
[KX509] Doster, W., Watts, M., and D. Hyde, "The KX.509
|
||||
Protocol", September 2001, <http://www.citi.umich.edu/
|
||||
techreports/reports/citi-tr-01-2.pdf>.
|
||||
|
||||
[RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
|
||||
specifying the location of services (DNS SRV)",
|
||||
RFC 2782, February 2000.
|
||||
|
||||
[RFC4211] Schaad, J., "Internet X.509 Public Key Infrastructure
|
||||
Certificate Request Message Format (CRMF)", RFC 4211,
|
||||
September 2005.
|
||||
|
||||
[RFC4556] Zhu, L. and B. Tung, "Public Key Cryptography for
|
||||
Initial Authentication in Kerberos (PKINIT)", RFC 4556,
|
||||
June 2006.
|
||||
|
||||
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer
|
||||
Security (TLS) Protocol Version 1.2", RFC 5246,
|
||||
August 2008.
|
||||
|
||||
[SLCS] "Short Lived Credential Services", February 2009,
|
||||
<http://tagpma.org/authn_profiles/slcs>.
|
||||
|
||||
[X.509] International Telecommunications Union, "Recommendation
|
||||
X.509: The Directory: Public-key and attribute
|
||||
certificate framework", November 2008.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Hotz & Allbery Informational [Page 11]
|
||||
|
||||
RFC 6717 kx509 August 2012
|
||||
|
||||
|
||||
Appendix A. Certificate Caching and Deployment Considerations
|
||||
|
||||
As noted in the Security Considerations section, the functional
|
||||
lifetime of the acquired X.509 certificate should usually match the
|
||||
lifetime of its predecessor Kerberos ticket. Therefore, it is likely
|
||||
that X.509 certificates issued with this protocol should be deleted
|
||||
when the supporting Kerberos tickets are deleted. That makes the
|
||||
Kerberos ticket cache a reasonable location to store the certificate
|
||||
(and its private key).
|
||||
|
||||
On the other hand, applications, such as web browsers, probably
|
||||
expect certificates in different stores.
|
||||
|
||||
A widely used solution to this dichotomy is to implement a PKCS11
|
||||
library that supports the kx509-acquired credentials. The
|
||||
credentials remain stored in the Kerberos credentials cache, but full
|
||||
PKI functionality is still available via a standard interface for PKI
|
||||
credentials.
|
||||
|
||||
Appendix B. Historic Extensions
|
||||
|
||||
This appendix documents extensions to the kx509 protocol that are
|
||||
either no longer in use or are expected to be dropped.
|
||||
|
||||
A subjectAltName othername extension of type kcaAuthRealm (OID value
|
||||
1.3.6.1.4.1.250.42.1) is frequently used to include the client's
|
||||
realm as an ASN.1 octet string.
|
||||
|
||||
The Microsoft-defined userPrincipalName has frequently been used for
|
||||
the same purpose as the id-pkinit-san.
|
||||
|
||||
The historic implementations of this protocol included provisions for
|
||||
DSA keys in place of RSA. DSA does not appear to be in use. A
|
||||
future version of this protocol will use a standard certificate
|
||||
request structure that will provide algorithm agility.
|
||||
|
||||
The historic implementations of this protocol allowed an optional
|
||||
client-version field (at the end of the request) of type
|
||||
VisibleString. If present, the KCA copied it into the issued
|
||||
certificate as an extension with the OID 1.3.6.1.4.1.250.42.2. This
|
||||
feature does not appear to be in use.
|
||||
|
||||
Appendix C. Example Exchange
|
||||
|
||||
The request and reply are from the same exchange. The Ethernet, IP,
|
||||
and UDP headers, and the 4-byte version string at the beginning of
|
||||
the request and reply packets are all omitted. Only the ASN.1-
|
||||
encoded portions are shown.
|
||||
|
||||
|
||||
|
||||
Hotz & Allbery Informational [Page 12]
|
||||
|
||||
RFC 6717 kx509 August 2012
|
||||
|
||||
|
||||
0:d=0 hl=4 l= 678 cons: SEQUENCE
|
||||
4:d=1 hl=4 l= 509 prim: OCTET STRING
|
||||
[HEX DUMP]:6E8201F9308201F5A003... (AP-REQ)
|
||||
517:d=1 hl=2 l= 20 prim: OCTET STRING
|
||||
[HEX DUMP]:ECFF1C922300D0E9DD02... (pk-hash)
|
||||
539:d=1 hl=3 l= 140 prim: OCTET STRING
|
||||
[HEX DUMP]:30818902818100B70F46... (pk-key)
|
||||
|
||||
Request Packet ASN.1 Decode
|
||||
|
||||
0:d=0 hl=4 l= 870 cons: SEQUENCE
|
||||
4:d=1 hl=2 l= 22 cons: cont [ 1 ]
|
||||
6:d=2 hl=2 l= 20 prim: OCTET STRING
|
||||
[HEX DUMP]:F3A844834C26D843B6FD... (hash)
|
||||
28:d=1 hl=4 l= 842 cons: cont [ 2 ]
|
||||
32:d=2 hl=4 l= 838 prim: OCTET STRING
|
||||
[HEX DUMP]:308203423082022AA003... (certificate)
|
||||
|
||||
Reply Packet ASN.1 Decode
|
||||
|
||||
Authors' Addresses
|
||||
|
||||
Henry B. Hotz
|
||||
Jet Propulsion Laboratory, California Institute of Technology
|
||||
4800 Oak Grove Dr.
|
||||
Pasadena, CA 91109
|
||||
USA
|
||||
|
||||
Phone: +01 818 354-4880
|
||||
EMail: hotz@jpl.nasa.gov
|
||||
|
||||
|
||||
Russ Allbery
|
||||
Stanford University
|
||||
P.O. Box 20066
|
||||
Stanford, CA 94309
|
||||
USA
|
||||
|
||||
EMail: rra@stanford.edu
|
||||
URI: http://www.eyrie.org/~eagle/
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Hotz & Allbery Informational [Page 13]
|
||||
|
||||
@@ -113,17 +113,13 @@ krb5_kdc_get_config(krb5_context context, krb5_kdc_configuration **config)
|
||||
"kdc", "enable-kx509", NULL);
|
||||
|
||||
if (c->enable_kx509) {
|
||||
/* These are global defaults. There are also per-realm defaults. */
|
||||
c->kx509_template =
|
||||
krb5_config_get_string(context, NULL,
|
||||
"kdc", "kx509_template", NULL);
|
||||
c->kx509_ca =
|
||||
krb5_config_get_string(context, NULL,
|
||||
"kdc", "kx509_ca", NULL);
|
||||
if (c->kx509_ca == NULL || c->kx509_template == NULL) {
|
||||
kdc_log(context, c, 0,
|
||||
"missing kx509 configuration, turning off");
|
||||
c->enable_kx509 = FALSE;
|
||||
}
|
||||
}
|
||||
#endif
|
||||
|
||||
|
||||
836
kdc/kx509.c
836
kdc/kx509.c
File diff suppressed because it is too large
Load Diff
@@ -150,10 +150,9 @@ kdc_kx509(krb5_context context,
|
||||
{
|
||||
Kx509Request kx509req;
|
||||
krb5_error_code ret;
|
||||
size_t len;
|
||||
|
||||
ret = _kdc_try_kx509_request(req_buffer->data, req_buffer->length,
|
||||
&kx509req, &len);
|
||||
&kx509req);
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
|
||||
@@ -37,10 +37,13 @@ kdestroy_LDADD = $(kinit_LDADD)
|
||||
|
||||
kimpersonate_LDADD = $(kinit_LDADD)
|
||||
|
||||
LIB_hx509 = ../lib/hx509/libhx509.la
|
||||
|
||||
heimtools_LDADD = \
|
||||
$(top_builddir)/lib/sl/libsl.la \
|
||||
$(kinit_LDADD) \
|
||||
$(LIB_readline)
|
||||
$(LIB_readline) \
|
||||
$(LIB_hx509)
|
||||
|
||||
dist_heimtools_SOURCES = heimtools.c klist.c kswitch.c copy_cred_cache.c
|
||||
nodist_heimtools_SOURCES = heimtools-commands.c
|
||||
|
||||
@@ -57,6 +57,7 @@ NOINSTPROGRAMS=\
|
||||
BINLIBS=\
|
||||
$(LIBHEIMDAL) \
|
||||
$(LIBHEIMNTLM) \
|
||||
$(LIBHX509) \
|
||||
!if !defined(NO_AFS)
|
||||
$(LIBKAFS) \
|
||||
!endif
|
||||
|
||||
@@ -114,6 +114,11 @@ command = {
|
||||
type = "flag"
|
||||
help = "Verbose output"
|
||||
}
|
||||
option = {
|
||||
long = "extract-kx509-cert"
|
||||
type = "string"
|
||||
help = "hx509 store for kx509 certificate and private key"
|
||||
}
|
||||
}
|
||||
command = {
|
||||
name = "kgetcred"
|
||||
|
||||
@@ -44,6 +44,8 @@
|
||||
.Fl Fl cache= Ns Ar cache
|
||||
.Xc
|
||||
.Oc
|
||||
.Oo Fl Fl extract-kx509-cert= Ns Ar hx509-store
|
||||
.Oc
|
||||
.Op Fl s | Fl t | Fl Fl test
|
||||
.Op Fl T | Fl Fl tokens
|
||||
.Op Fl 5 | Fl Fl v5
|
||||
@@ -65,6 +67,17 @@ credential cache to list
|
||||
.It Fl s , Fl t , Fl Fl test
|
||||
Test for there being an active and valid TGT for the local realm of
|
||||
the user in the credential cache.
|
||||
.It Fl Fl extract-kx509-cert= Ns Ar hx509-store
|
||||
An hx509 store specification, such as
|
||||
.Va DER-FILE:/path/to/der/file ,
|
||||
.Va PEM-FILE:/path/to/PEM/file ,
|
||||
.Va FILE:/path/to/PEM/file ,
|
||||
or
|
||||
.Va PKCS12:/path/to/PKCS#12/file
|
||||
into which to store any PKIX certificate and private key
|
||||
(unencrypted) that may have been acquired with the kx509 protocol
|
||||
and stored in the
|
||||
.Ns Ar ccache.
|
||||
.It Fl T , Fl Fl tokens
|
||||
display AFS tokens
|
||||
.It Fl 5 , Fl Fl v5
|
||||
|
||||
126
kuser/klist.c
126
kuser/klist.c
@@ -36,6 +36,10 @@
|
||||
#include "kuser_locl.h"
|
||||
#include "parse_units.h"
|
||||
#include "heimtools-commands.h"
|
||||
#include <kx509_asn1.h>
|
||||
#undef HC_DEPRECATED_CRYPTO
|
||||
#include "../lib/hx509/hx_locl.h"
|
||||
#include "hx509-private.h"
|
||||
|
||||
static char*
|
||||
printable_time_internal(time_t t, int x)
|
||||
@@ -173,6 +177,7 @@ print_cred_verbose(krb5_context context, krb5_creds *cred, int do_json)
|
||||
strcmp(s, "FriendlyName") == 0 ||
|
||||
strcmp(s, "fast_avail") == 0 ||
|
||||
strcmp(s, "kx509store") == 0 ||
|
||||
strcmp(s, "kx509_service_realm") == 0 ||
|
||||
strcmp(s, "kx509_service_status") == 0)
|
||||
printf(N_("Configuration item payload: %.*s\n", ""),
|
||||
(int)cred->ticket.length,
|
||||
@@ -253,22 +258,34 @@ print_cred_verbose(krb5_context context, krb5_creds *cred, int do_json)
|
||||
*/
|
||||
|
||||
static void
|
||||
print_tickets (krb5_context context,
|
||||
krb5_ccache ccache,
|
||||
krb5_principal principal,
|
||||
int do_verbose,
|
||||
int do_flags,
|
||||
int do_hidden,
|
||||
int do_json)
|
||||
print_tickets(krb5_context context,
|
||||
krb5_ccache ccache,
|
||||
krb5_principal principal,
|
||||
int do_verbose,
|
||||
int do_flags,
|
||||
int do_hidden,
|
||||
int do_json,
|
||||
const char *hx509_store)
|
||||
{
|
||||
char *str, *name, *fullname;
|
||||
char *kx509_realm = NULL;
|
||||
hx509_private_key key = NULL;
|
||||
hx509_context hx509ctx = NULL;
|
||||
hx509_certs certs = NULL;
|
||||
hx509_cert cert = NULL;
|
||||
krb5_error_code kx509_ret = 0;
|
||||
krb5_error_code ret;
|
||||
krb5_cc_cursor cursor;
|
||||
krb5_creds creds;
|
||||
krb5_deltat sec;
|
||||
int print_comma = 0;
|
||||
|
||||
rtbl_t ct = NULL;
|
||||
int print_comma = 0;
|
||||
int kx509_disabled = 0;
|
||||
int cert_stored = 0;
|
||||
int cert_seen = 0;
|
||||
|
||||
if (hx509_store)
|
||||
kx509_ret = hx509_context_init(&hx509ctx);
|
||||
|
||||
ret = krb5_unparse_name (context, principal, &str);
|
||||
if (ret)
|
||||
@@ -341,6 +358,45 @@ print_tickets (krb5_context context,
|
||||
if (do_verbose && do_json)
|
||||
printf("\"tickets\" : [");
|
||||
while ((ret = krb5_cc_next_cred(context, ccache, &cursor, &creds)) == 0) {
|
||||
if (krb5_is_config_principal(context, creds.server) &&
|
||||
krb5_principal_get_num_comp(context, creds.server) == 2 &&
|
||||
hx509_store) {
|
||||
const char *s;
|
||||
|
||||
s = krb5_principal_get_comp_string(context, creds.server, 1);
|
||||
if (strcmp(s, "kx509_service_status") == 0) {
|
||||
kx509_disabled = 1;
|
||||
} else if (strcmp(s, "kx509_service_realm") == 0) {
|
||||
kx509_realm = strndup(creds.ticket.data, creds.ticket.length);
|
||||
} else if (strcmp(s, "kx509cert") == 0) {
|
||||
cert = hx509_cert_init_data(hx509ctx, creds.ticket.data,
|
||||
creds.ticket.length, NULL);
|
||||
} else if (strcmp(s, "kx509key") == 0) {
|
||||
(void) hx509_parse_private_key(hx509ctx, NULL,
|
||||
creds.ticket.data,
|
||||
creds.ticket.length,
|
||||
HX509_KEY_FORMAT_PKCS8, &key);
|
||||
}
|
||||
if (hx509ctx && cert && key && !cert_seen) {
|
||||
/* Now store the cert and key into the given hx509 store */
|
||||
(void) _hx509_cert_assign_key(cert, key);
|
||||
kx509_ret = hx509_certs_init(hx509ctx, hx509_store,
|
||||
HX509_CERTS_CREATE, NULL, &certs);
|
||||
if (kx509_ret == 0)
|
||||
kx509_ret = hx509_certs_add(hx509ctx, certs, cert);
|
||||
if (kx509_ret == 0)
|
||||
kx509_ret = hx509_certs_store(hx509ctx, certs, 0, NULL);
|
||||
|
||||
/*
|
||||
* Wait till we're done listing the ccache to complain about
|
||||
* failing to extract the cert and priv key.
|
||||
*/
|
||||
cert_seen = 1;
|
||||
if (kx509_ret == 0)
|
||||
cert_stored = 1;
|
||||
}
|
||||
}
|
||||
|
||||
if (!do_hidden && krb5_is_config_principal(context, creds.server)) {
|
||||
;
|
||||
} else if (do_verbose) {
|
||||
@@ -353,12 +409,47 @@ print_tickets (krb5_context context,
|
||||
}
|
||||
krb5_free_cred_contents(context, &creds);
|
||||
}
|
||||
print_comma = 0;
|
||||
if(ret != KRB5_CC_END)
|
||||
if (ret != KRB5_CC_END)
|
||||
krb5_err(context, 1, ret, "krb5_cc_get_next");
|
||||
ret = krb5_cc_end_seq_get (context, ccache, &cursor);
|
||||
if (ret)
|
||||
krb5_err (context, 1, ret, "krb5_cc_end_seq_get");
|
||||
krb5_err(context, 1, ret, "krb5_cc_end_seq_get");
|
||||
|
||||
/* Finish kx509 extraction error checking */
|
||||
if (hx509_store && cert_seen && !cert_stored) {
|
||||
if (!hx509ctx)
|
||||
krb5_err(context, 1, kx509_ret,
|
||||
N_("Failed to store certificate and private key "
|
||||
"in %s due to failure to initialize context: %s", ""),
|
||||
hx509_store, hx509_get_error_string(hx509ctx, kx509_ret));
|
||||
if (!cert || !key)
|
||||
krb5_err(context, 1, kx509_ret,
|
||||
N_("Failed to store certificate and private key "
|
||||
"in %s due to failure to parse them: %s", ""),
|
||||
hx509_store, hx509_get_error_string(hx509ctx, kx509_ret));
|
||||
krb5_err(context, 1, kx509_ret, N_("Failed to store certificate and "
|
||||
"private key in %s", ""),
|
||||
hx509_store);
|
||||
}
|
||||
if (hx509_store && !cert_seen) {
|
||||
/* No PKIX creds in ccache, but maybe we can run kx509 now */
|
||||
if (kx509_disabled)
|
||||
krb5_errx(context, 1, N_("The kx509 protocol is disabled at the "
|
||||
"KDC for realm %s", ""),
|
||||
kx509_realm ? kx509_realm : "<out of memory>");
|
||||
ret = krb5_kx509_ext(context, ccache, NULL, NULL, NULL, 0, hx509_store,
|
||||
NULL);
|
||||
if (ret)
|
||||
krb5_err(context, 1, ret, N_("Failed to acquire certificate and "
|
||||
"store it and private key in %s", ""),
|
||||
hx509_store);
|
||||
}
|
||||
hx509_private_key_free(&key);
|
||||
hx509_certs_free(&certs);
|
||||
hx509_cert_free(cert);
|
||||
hx509_context_free(&hx509ctx);
|
||||
|
||||
print_comma = 0;
|
||||
if(!do_verbose) {
|
||||
rtbl_format(ct, stdout);
|
||||
rtbl_destroy(ct);
|
||||
@@ -368,6 +459,7 @@ print_tickets (krb5_context context,
|
||||
printf("]");
|
||||
printf("}");
|
||||
}
|
||||
free(fullname);
|
||||
}
|
||||
|
||||
/*
|
||||
@@ -474,7 +566,7 @@ static int
|
||||
display_v5_ccache (krb5_context context, krb5_ccache ccache,
|
||||
int do_test, int do_verbose,
|
||||
int do_flags, int do_hidden,
|
||||
int do_json)
|
||||
int do_json, const char *hx509_store)
|
||||
{
|
||||
krb5_error_code ret;
|
||||
krb5_principal principal;
|
||||
@@ -499,7 +591,7 @@ display_v5_ccache (krb5_context context, krb5_ccache ccache,
|
||||
exit_status = check_expiration(context, ccache, NULL);
|
||||
else
|
||||
print_tickets (context, ccache, principal, do_verbose,
|
||||
do_flags, do_hidden, do_json);
|
||||
do_flags, do_hidden, do_json, hx509_store);
|
||||
|
||||
ret = krb5_cc_close (context, ccache);
|
||||
if (ret)
|
||||
@@ -646,7 +738,8 @@ klist(struct klist_options *opt, int argc, char **argv)
|
||||
|
||||
exit_status |= display_v5_ccache(heimtools_context, id, do_test,
|
||||
do_verbose, opt->flags_flag,
|
||||
opt->hidden_flag, opt->json_flag);
|
||||
opt->hidden_flag, opt->json_flag,
|
||||
opt->extract_kx509_cert_string);
|
||||
if (!opt->json_flag)
|
||||
printf("\n\n");
|
||||
|
||||
@@ -667,7 +760,8 @@ klist(struct klist_options *opt, int argc, char **argv)
|
||||
}
|
||||
exit_status = display_v5_ccache(heimtools_context, id, do_test,
|
||||
do_verbose, opt->flags_flag,
|
||||
opt->hidden_flag, opt->json_flag);
|
||||
opt->hidden_flag, opt->json_flag,
|
||||
opt->extract_kx509_cert_string);
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
@@ -1,5 +1,7 @@
|
||||
-- $Id$
|
||||
|
||||
-- The kx509 protocol is documented in RFC6717.
|
||||
|
||||
KX509 DEFINITIONS ::=
|
||||
BEGIN
|
||||
|
||||
@@ -12,20 +14,134 @@ KX509-ERROR-CODE ::= INTEGER {
|
||||
KX509-STATUS-SERVER-TEMP(5),
|
||||
-- 6 is used internally in the umich client, avoid that
|
||||
KX509-STATUS-SERVER-KEY(7)
|
||||
-- Let us reserve 1000+ for Kebreros protocol wire error codes -Nico
|
||||
}
|
||||
|
||||
-- Version 2, which has no proof of possession
|
||||
Kx509Request ::= SEQUENCE {
|
||||
authenticator OCTET STRING,
|
||||
pk-hash OCTET STRING,
|
||||
pk-key OCTET STRING
|
||||
pk-hash OCTET STRING, -- HMAC(ticket_session_key, pk-key)
|
||||
pk-key OCTET STRING -- the public key, DER-encoded (RSA, basically)
|
||||
}
|
||||
|
||||
-- Kx509ErrorCode is a Heimdal-specific enhancement with no change on the wire,
|
||||
-- and really only just so the error-code field below can fit on one line.
|
||||
Kx509ErrorCode ::= INTEGER (-2147483648..2147483647)
|
||||
|
||||
Kx509Response ::= SEQUENCE {
|
||||
error-code[0] INTEGER (-2147483648..2147483647)
|
||||
OPTIONAL -- DEFAULT 0 --,
|
||||
hash[1] OCTET STRING OPTIONAL,
|
||||
certificate[2] OCTET STRING OPTIONAL,
|
||||
error-code[0] Kx509ErrorCode DEFAULT 0,
|
||||
hash[1] OCTET STRING OPTIONAL, -- HMAC(session_key, ...)
|
||||
certificate[2] OCTET STRING OPTIONAL, -- Certificates (plural)
|
||||
-- if client used a
|
||||
-- Kx509CSRPlus
|
||||
e-text[3] VisibleString OPTIONAL
|
||||
}
|
||||
|
||||
-- Offset for Kerberos protocol errors when error-code set to one:
|
||||
kx509-krb5-error-base INTEGER ::= 1000
|
||||
|
||||
-- RFC6717 says this about error codes:
|
||||
--
|
||||
-- +------------+-----------------------------+------------------------+
|
||||
-- | error-code | Condition | Example |
|
||||
-- +------------+-----------------------------+------------------------+
|
||||
-- | 1 | Permanent problem with | Incompatible version |
|
||||
-- | | client request | |
|
||||
-- | 2 | Solvable problem with | Expired Kerberos |
|
||||
-- | | client request | credentials |
|
||||
-- | 3 | Temporary problem with | Packet loss |
|
||||
-- | | client request | |
|
||||
-- | 4 | Permanent problem with the | Internal |
|
||||
-- | | server | misconfiguration |
|
||||
-- | 5 | Temporary problem with the | Server overloaded |
|
||||
-- | | server | |
|
||||
-- +------------+-----------------------------+------------------------+
|
||||
--
|
||||
-- Looking at UMich CITI's kca (server-side of kx509) implementation, it always
|
||||
-- sends 0 as the status code, and the UMich CITI kx509 client never checks it.
|
||||
-- All of these error codes are local only in the UMich CITI implementation.
|
||||
--
|
||||
-- Meanwhile, Heimdal used to never send error responses at all.
|
||||
--
|
||||
-- As a result we can use whatever error codes we want. We'll send Kerberos
|
||||
-- protocol errors + 1000. And we'll never use RFC6717 error codes at all.
|
||||
--
|
||||
-- Looking at umich source...
|
||||
--
|
||||
-- #define KX509_STATUS_GOOD 0 /* No problems handling client request */
|
||||
-- #define KX509_STATUS_CLNT_BAD 1 /* Client-side permanent problem */
|
||||
-- /* ex. version incompatible */
|
||||
-- #define KX509_STATUS_CLNT_FIX 2 /* Client-side solvable problem */
|
||||
-- /* ex. re-authenticate */
|
||||
-- #define KX509_STATUS_CLNT_TMP 3 /* Client-side temporary problem */
|
||||
-- /* ex. packet loss */
|
||||
-- #define KX509_STATUS_SRVR_BAD 4 /* Server-side permanent problem */
|
||||
-- /* ex. server broken */
|
||||
-- #define KX509_STATUS_SRVR_TMP 5 /* Server-side temporary problem */
|
||||
-- /* ex. server overloaded */
|
||||
-- #define KX509_STATUS_SRVR_CANT_CLNT_VERS 6 /* Server-side doesn't handle */
|
||||
-- /* existence of client_version */
|
||||
-- /* field in KX509_REQUEST */
|
||||
--
|
||||
-- The umich server uses these errors in these situations:
|
||||
--
|
||||
-- - KX509_STATUS_SRVR_TMP is for:
|
||||
-- - request decode errors
|
||||
-- - krb5_is_ap_req() errors
|
||||
-- - wrong Kerberos protocol vno in AP-REQ
|
||||
-- - some ENOMEMs
|
||||
-- - UDP read errors (??)
|
||||
-- - LDAP issues (they use LDAP to map realm-chopped user princ names to
|
||||
-- full names)
|
||||
-- - pk decode errors
|
||||
-- - KX509_STATUS_CLNT_TMP is for:
|
||||
-- - HMAC mismatch
|
||||
-- - some ENOMEMs
|
||||
-- - failure to accept AP-REQ
|
||||
-- - failure to unparse princ names from AP-REQ's Ticket
|
||||
-- - KX509_STATUS_SRVR_BAD is for:
|
||||
-- - configuration issues (missing issuer creds)
|
||||
-- - serial number transaction issues (we should randomize)
|
||||
-- - subjectName construction issues
|
||||
-- - certificate construction issues (ENOMEM, say)
|
||||
-- - failure to authenticate (never happens, since KX509_STATUS_CLNT_TMP is
|
||||
-- used earlier when krb5_rd_req() fails)
|
||||
-- - KX509_STATUS_CLNT_FIX is for:
|
||||
-- - more than one component client principals
|
||||
-- - client princ name component zero string length shorter than 3 or
|
||||
-- longer than 8 (WTF)
|
||||
-- - other policy issues
|
||||
-- - KX509_STATUS_CLNT_BAD
|
||||
-- - wrong protocol version number (version_2_0)
|
||||
|
||||
-- Possible new version designs:
|
||||
--
|
||||
-- - keep the protocol the same but use a CSR instead of a raw RSA public key
|
||||
-- - on the server try decoding first a CSR, then a raw RSA public key
|
||||
--
|
||||
-- - keep the protocol the same but use either a CSR or a self-signed cert
|
||||
-- - on the server try decoding first a Certificate, then a CSR, then a raw
|
||||
-- RSA public key
|
||||
--
|
||||
-- CSRs are a pain to deal with. Self-signed certificates can act as a
|
||||
-- CSR of a sort. Use notBefore == 1970-01-01T00:00:00Z and an EKU
|
||||
-- denoting "this certificate is really a much-easier-to-work-with CSR
|
||||
-- alternative".
|
||||
--
|
||||
-- - keep the protocol similar, but use the checksum field of the
|
||||
-- Authenticator to authenticate the request data; use a KRB-PRIV for the
|
||||
-- reply
|
||||
--
|
||||
-- - extend the KDC/AS/TGS protocols to support certificate issuance, either
|
||||
-- at the same time as ticket acquisition, or as an alternative
|
||||
-- - send a CSR as a authz-data element
|
||||
-- - expect an EncryptedData with the issued Certificate inside as the
|
||||
-- Ticket in the result (again, ugly hack)
|
||||
-- - or maybe just add new messages, but, the thing is that the existing
|
||||
-- "AP-REP + stuff" kx509 protocol is a fine design pattern, there's no
|
||||
-- need to radically change it, just slightly.
|
||||
--
|
||||
-- The main benefit of using an extension to the KDC/AS/TGS protocols is that
|
||||
-- we could then use FAST for confidentiality protection.
|
||||
|
||||
END
|
||||
|
||||
@@ -71,7 +71,7 @@ libkrb5_la_LIBADD = \
|
||||
$(top_builddir)/lib/ipc/libheim-ipcc.la \
|
||||
$(top_builddir)/lib/wind/libwind.la \
|
||||
$(top_builddir)/lib/base/libheimbase.la \
|
||||
$(LIB_pkinit) \
|
||||
$(top_builddir)/lib/hx509/libhx509.la \
|
||||
$(LIB_openssl_crypto) \
|
||||
$(use_sqlite) \
|
||||
$(LIB_com_err) \
|
||||
@@ -100,7 +100,7 @@ librfc3961_la_LIBADD = \
|
||||
|
||||
lib_LTLIBRARIES = libkrb5.la
|
||||
|
||||
ERR_FILES = krb5_err.c krb_err.c heim_err.c k524_err.c k5e1_err.c
|
||||
ERR_FILES = krb5_err.c krb_err.c heim_err.c k524_err.c k5e1_err.c kx509_err.c
|
||||
|
||||
libkrb5_la_CPPFLAGS = \
|
||||
-DBUILD_KRB5_LIB \
|
||||
@@ -191,6 +191,7 @@ dist_libkrb5_la_SOURCES = \
|
||||
krbhst.c \
|
||||
kuserok.c \
|
||||
kuserok_plugin.h \
|
||||
kx509.c \
|
||||
log.c \
|
||||
mcache.c \
|
||||
misc.c \
|
||||
@@ -281,7 +282,8 @@ ALL_OBJECTS += $(test_renew_OBJECTS)
|
||||
ALL_OBJECTS += $(test_rfc3961_OBJECTS)
|
||||
|
||||
$(ALL_OBJECTS): $(srcdir)/krb5-protos.h $(srcdir)/krb5-private.h
|
||||
$(ALL_OBJECTS): krb5_err.h heim_err.h k524_err.h k5e1_err.h krb_err.h k524_err.h
|
||||
$(ALL_OBJECTS): krb5_err.h heim_err.h k524_err.h k5e1_err.h \
|
||||
krb_err.h k524_err.h kx509_err.h
|
||||
|
||||
librfc3961_la_SOURCES = \
|
||||
crc.c \
|
||||
@@ -385,7 +387,7 @@ dist_include_HEADERS = \
|
||||
noinst_HEADERS = $(srcdir)/krb5-private.h
|
||||
|
||||
|
||||
nodist_include_HEADERS = krb5_err.h heim_err.h k524_err.h k5e1_err.h
|
||||
nodist_include_HEADERS = krb5_err.h heim_err.h k524_err.h k5e1_err.h kx509_err.h
|
||||
|
||||
# XXX use nobase_include_HEADERS = krb5/locate_plugin.h
|
||||
krb5dir = $(includedir)/krb5
|
||||
@@ -409,9 +411,10 @@ CLEANFILES = \
|
||||
krb_err.c krb_err.h \
|
||||
heim_err.c heim_err.h \
|
||||
k524_err.c k524_err.h \
|
||||
k5e1_err.c k5e1_err.h
|
||||
k5e1_err.c k5e1_err.h \
|
||||
kx509_err.c kx509_err.h
|
||||
|
||||
$(libkrb5_la_OBJECTS): krb5_err.h krb_err.h heim_err.h k524_err.h k5e1_err.h
|
||||
$(libkrb5_la_OBJECTS): krb5_err.h krb_err.h heim_err.h k524_err.h k5e1_err.h kx509_err.h
|
||||
|
||||
test_config_strings.out: test_config_strings.cfg
|
||||
$(CP) $(srcdir)/test_config_strings.cfg test_config_strings.out
|
||||
@@ -427,6 +430,7 @@ EXTRA_DIST = \
|
||||
heim_err.et \
|
||||
k524_err.et \
|
||||
k5e1_err.et \
|
||||
kx509_err.et \
|
||||
$(man_MANS) \
|
||||
version-script.map \
|
||||
test_config_strings.cfg \
|
||||
@@ -445,3 +449,5 @@ heim_err.h: heim_err.et
|
||||
k524_err.h: k524_err.et
|
||||
|
||||
k5e1_err.h: k5e1_err.et
|
||||
|
||||
kx509_err.h: kx509_err.et
|
||||
|
||||
@@ -103,6 +103,7 @@ libkrb5_OBJS = \
|
||||
$(OBJ)\keytab_memory.obj \
|
||||
$(OBJ)\krbhst.obj \
|
||||
$(OBJ)\kuserok.obj \
|
||||
$(OBJ)\kx509.obj \
|
||||
$(OBJ)\log.obj \
|
||||
$(OBJ)\mcache.obj \
|
||||
$(OBJ)\misc.obj \
|
||||
@@ -173,6 +174,7 @@ INCFILES= \
|
||||
$(INCDIR)\heim_err.h \
|
||||
$(INCDIR)\k524_err.h \
|
||||
$(INCDIR)\k5e1_err.h \
|
||||
$(INCDIR)\kx509_err.h \
|
||||
$(INCDIR)\kcm.h \
|
||||
$(INCDIR)\krb_err.h \
|
||||
$(INCDIR)\krb5.h \
|
||||
@@ -268,6 +270,7 @@ dist_libkrb5_la_SOURCES = \
|
||||
krb5-v4compat.h \
|
||||
krbhst.c \
|
||||
kuserok.c \
|
||||
kx509.c \
|
||||
log.c \
|
||||
mcache.c \
|
||||
misc.c \
|
||||
@@ -360,6 +363,11 @@ $(OBJ)\k5e1_err.c $(OBJ)\k5e1_err.h: k5e1_err.et
|
||||
$(BINDIR)\compile_et.exe $(SRCDIR)\k5e1_err.et
|
||||
cd $(SRCDIR)
|
||||
|
||||
$(OBJ)\kx509_err.c $(OBJ)\kx509_err.h: kx509_err.et
|
||||
cd $(OBJ)
|
||||
$(BINDIR)\compile_et.exe $(SRCDIR)\kx509_err.et
|
||||
cd $(SRCDIR)
|
||||
|
||||
#----------------------------------------------------------------------
|
||||
# libkrb5
|
||||
|
||||
|
||||
121
lib/krb5/cache.c
121
lib/krb5/cache.c
@@ -716,8 +716,12 @@ krb5_cc_initialize(krb5_context context,
|
||||
krb5_error_code ret;
|
||||
|
||||
ret = (*id->ops->init)(context, id, primary_principal);
|
||||
if (ret == 0)
|
||||
id->initialized = 1;
|
||||
if (ret == 0) {
|
||||
id->cc_kx509_done = 0;
|
||||
id->cc_initialized = 1;
|
||||
id->cc_need_start_realm = 1;
|
||||
id->cc_start_tgt_stored = 0;
|
||||
}
|
||||
return ret;
|
||||
}
|
||||
|
||||
@@ -735,11 +739,32 @@ KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
|
||||
krb5_cc_destroy(krb5_context context,
|
||||
krb5_ccache id)
|
||||
{
|
||||
krb5_error_code ret2 = 0;
|
||||
krb5_error_code ret;
|
||||
krb5_data d;
|
||||
|
||||
/*
|
||||
* Destroy associated hx509 PKIX credential store created by krb5_kx509*().
|
||||
*/
|
||||
if ((ret = krb5_cc_get_config(context, id, NULL, "kx509store", &d)) == 0) {
|
||||
char *name;
|
||||
|
||||
if ((name = strndup(d.data, d.length)) == NULL) {
|
||||
ret2 = krb5_enomem(context);
|
||||
} else {
|
||||
hx509_certs certs;
|
||||
ret = hx509_certs_init(context->hx509ctx, name, 0, NULL, &certs);
|
||||
if (ret == 0)
|
||||
ret2 = hx509_certs_destroy(context->hx509ctx, &certs);
|
||||
else
|
||||
hx509_certs_free(&certs);
|
||||
free(name);
|
||||
}
|
||||
}
|
||||
|
||||
ret = (*id->ops->destroy)(context, id);
|
||||
krb5_cc_close (context, id);
|
||||
return ret;
|
||||
(void) krb5_cc_close(context, id);
|
||||
return ret ? ret : ret2;
|
||||
}
|
||||
|
||||
/**
|
||||
@@ -756,6 +781,44 @@ krb5_cc_close(krb5_context context,
|
||||
krb5_ccache id)
|
||||
{
|
||||
krb5_error_code ret;
|
||||
|
||||
/*
|
||||
* We want to automatically acquire a PKIX credential using kx509.
|
||||
*
|
||||
* This can be slow if we're generating an RSA key. Plus it means talking
|
||||
* to the KDC.
|
||||
*
|
||||
* We only want to do this when:
|
||||
*
|
||||
* - krb5_cc_initialize() was called on this ccache handle,
|
||||
* - a start TGT was stored (actually, a cross-realm TGT would do),
|
||||
*
|
||||
* and
|
||||
*
|
||||
* - we aren't creating a gss_cred_id_t for a delegated credential.
|
||||
*
|
||||
* We only have a heuristic for the last condition: that `id' is not a
|
||||
* MEMORY ccache, which is what's used for delegated credentials.
|
||||
*
|
||||
* We really only want to do this when storing a credential in a user's
|
||||
* default ccache, but we leave it to krb5_kx509() to do that check.
|
||||
*
|
||||
* XXX Perhaps we should do what krb5_kx509() does here, and just call
|
||||
* krb5_kx509_ext() (renamed to krb5_kx509()). Then we wouldn't need
|
||||
* the delegated cred handle heuristic.
|
||||
*/
|
||||
if (id->cc_initialized && id->cc_start_tgt_stored && !id->cc_kx509_done &&
|
||||
strcmp("MEMORY", krb5_cc_get_type(context, id)) != 0) {
|
||||
_krb5_debug(context, 2, "attempting to fetch a certificate using "
|
||||
"kx509");
|
||||
ret = krb5_kx509(context, id, NULL);
|
||||
if (ret)
|
||||
_krb5_debug(context, 2, "failed to fetch a certificate");
|
||||
else
|
||||
_krb5_debug(context, 2, "fetched a certificate");
|
||||
ret = 0;
|
||||
}
|
||||
|
||||
ret = (*id->ops->close)(context, id);
|
||||
free(id);
|
||||
return ret;
|
||||
@@ -777,31 +840,49 @@ krb5_cc_store_cred(krb5_context context,
|
||||
{
|
||||
krb5_error_code ret;
|
||||
krb5_data realm;
|
||||
const char *cfg = "";
|
||||
|
||||
ret = (*id->ops->store)(context, id, creds);
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
/* Look for and mark the first root TGT's realm as the start realm */
|
||||
if (ret == 0 && id->initialized &&
|
||||
/* Automatic cc_config-setting and other actions */
|
||||
if (krb5_principal_get_num_comp(context, creds->server) > 1 &&
|
||||
krb5_is_config_principal(context, creds->server))
|
||||
cfg = krb5_principal_get_comp_string(context, creds->server, 1);
|
||||
|
||||
if (id->cc_initialized && !id->cc_start_tgt_stored &&
|
||||
krb5_principal_is_root_krbtgt(context, creds->server)) {
|
||||
|
||||
id->initialized = 0;
|
||||
/* Mark the first root TGT's realm as the start realm */
|
||||
id->cc_start_tgt_stored = 1;
|
||||
id->cc_need_start_realm = 0;
|
||||
realm.length = strlen(creds->server->realm);
|
||||
realm.data = creds->server->realm;
|
||||
(void) krb5_cc_set_config(context, id, NULL, "start_realm", &realm);
|
||||
} else if (ret == 0 && id->initialized &&
|
||||
krb5_is_config_principal(context, creds->server) &&
|
||||
strcmp(creds->server->name.name_string.val[1], "start_realm") == 0) {
|
||||
|
||||
} else if (id->cc_initialized && id->cc_start_tgt_stored &&
|
||||
!id->cc_kx509_done && strcmp(cfg, "kx509cert") == 0) {
|
||||
/*
|
||||
* But if the caller is storing a start_realm ccconfig, then
|
||||
* stop looking for root TGTs to mark as the start_realm.
|
||||
*
|
||||
* By honoring any start_realm cc config stored, we interop
|
||||
* both, with ccache implementations that don't preserve
|
||||
* insertion order, and Kerberos implementations that store this
|
||||
* cc config before the TGT.
|
||||
* Do not attempt kx509 at cc close time -- we're copying a ccache and
|
||||
* we've already got a cert (and private key).
|
||||
*/
|
||||
id->initialized = 0;
|
||||
id->cc_kx509_done = 1;
|
||||
} else if (id->cc_initialized && id->cc_start_tgt_stored &&
|
||||
!id->cc_kx509_done && strcmp(cfg, "kx509_service_status") == 0) {
|
||||
/*
|
||||
* Do not attempt kx509 at cc close time -- we're copying a ccache and
|
||||
* we know the kx509 service is not available.
|
||||
*/
|
||||
id->cc_kx509_done = 1;
|
||||
} else if (id->cc_initialized && strcmp(cfg, "start_realm") == 0) {
|
||||
/*
|
||||
* If the caller is storing a start_realm ccconfig, then stop looking
|
||||
* for root TGTs to mark as the start_realm.
|
||||
*
|
||||
* By honoring any start_realm cc config stored, we interop both, with
|
||||
* ccache implementations that don't preserve insertion order, and
|
||||
* Kerberos implementations that store this cc config before the TGT.
|
||||
*/
|
||||
id->cc_need_start_realm = 0;
|
||||
}
|
||||
return ret;
|
||||
}
|
||||
|
||||
@@ -342,6 +342,28 @@ be allowed to run.
|
||||
.It Li fcache_strict_checking
|
||||
strict checking in FILE credential caches that owner, no symlink and
|
||||
permissions is correct.
|
||||
.It Li enable-kx509 = Va boolean
|
||||
Enable use of kx509 so that every TGT that can has a corresponding
|
||||
PKIX certificate. Default: false.
|
||||
.It Li kx509_gen_key_type = Va public-key-type
|
||||
Type of public key for kx509 private key generation. Defaults to
|
||||
.Va rsa
|
||||
and currently only
|
||||
.Va rsa
|
||||
is supported.
|
||||
.It Li kx509_gen_rsa_key_size = Va number-of-bits
|
||||
RSA key size for kx509. Defaults to 2048.
|
||||
.It Li kx509_store = path
|
||||
A file path into which to write a certificate obtained with
|
||||
kx509, and its private key, when attempting kx509 optimistically
|
||||
using credentials from a default ccache. Tokens will be
|
||||
expanded.
|
||||
.It Li kx509_hostname = Va hostname
|
||||
If set, then the kx509 client will use this hostname for the
|
||||
kx509 service. This can also be set in the
|
||||
.Li [realm]
|
||||
section on a per-realm basis. If not set then a TGS name will be
|
||||
used.
|
||||
.It Li name_canon_rules = Va rules
|
||||
One or more service principal name canonicalization rules. Each rule
|
||||
consists of one or more tokens separated by colon (':'). Currently
|
||||
@@ -706,6 +728,8 @@ Should the kdc answer digest requests. The default is FALSE.
|
||||
.It Li digests_allowed = Va list of digests
|
||||
Specifies the digests the kdc will reply to. The default is
|
||||
.Li ntlm-v2 .
|
||||
.It Li enable-kx509 = Va boolean
|
||||
Enables kx509 service.
|
||||
.It Li kx509_ca = Va file
|
||||
Specifies the PEM credentials for the kx509 certification authority.
|
||||
.It Li require_initial_kca_tickets = Va boolean
|
||||
@@ -718,13 +742,31 @@ Defaults to true for the global setting.
|
||||
If true then the kx509 client principal's name and realm will be
|
||||
included in an
|
||||
.Li id-pkinit-san
|
||||
certificate extension.
|
||||
subject alternative name certificate extension.
|
||||
This can be set on a per-realm basis as well as globally.
|
||||
Defaults to true for the global setting.
|
||||
.It Li kx509_include_email_san = Va boolean
|
||||
If true then the kx509 client user principal's name and realm will be
|
||||
included in an
|
||||
.Li rfc822Name
|
||||
subject alternative name certificate extension, with the downcased
|
||||
realm as the domainname.
|
||||
This can be set on a per-realm basis as well as globally.
|
||||
Defaults to false for the global setting.
|
||||
.It Li kx509_include_dnsname_san = Va boolean
|
||||
If true then the kx509 host-based or domain-based client principal's
|
||||
hostname will be included in an
|
||||
.Li dNSName
|
||||
subject alternative name certificate extension, with the
|
||||
downcased realm as the domainname. This can be set on a
|
||||
per-realm basis as well as
|
||||
globally. Defaults to false for the global setting.
|
||||
.It Li kx509_template = Va file
|
||||
Specifies the PEM file with a template for the certificates to be
|
||||
issued.
|
||||
The following variables can be interpolated in the subject name using
|
||||
issued to kx509 clients whose principal names have one component
|
||||
(i.e., are user principals). A template is a certificate with
|
||||
variables to be interpolated in the subjectName. The following
|
||||
variables can be interpolated in the subject name using
|
||||
${variable} syntax:
|
||||
.Bl -tag -width "xxx" -offset indent
|
||||
.It principal-name
|
||||
@@ -734,6 +776,53 @@ The full name of the kx509 client principal, excluding the realm name.
|
||||
.It principal-name-realm
|
||||
The name of the client principal's realm.
|
||||
.El
|
||||
.It Li kx509_templates = {
|
||||
.Bl -tag -width "xxx" -offset indent
|
||||
.It Li two_component_user = {
|
||||
.Bl -tag -width "xxx" -offset indent
|
||||
.It Va first-component-of-principal-name = Va file
|
||||
.It ...
|
||||
.It Li }
|
||||
.El
|
||||
.It Li hostbased = {
|
||||
.Bl -tag -width "xxx" -offset indent
|
||||
.It Va service = Va file
|
||||
.It ...
|
||||
.It Li }
|
||||
.El
|
||||
.It Li domainbased = {
|
||||
.Bl -tag -width "xxx" -offset indent
|
||||
.It Va service = Va file
|
||||
.It ...
|
||||
.It Li }
|
||||
.El
|
||||
.It Li }
|
||||
.El
|
||||
Specifies the PEM files with templates for the certificates to be
|
||||
issued to clients with principal names with two or three name
|
||||
components. This is useful for issuing server certificates to
|
||||
host-based principals. The following variables can be
|
||||
interpolated in the subject name using
|
||||
.Va ${variable}
|
||||
syntax:
|
||||
.Bl -tag -width "xxx" -offset indent
|
||||
.It principal-name
|
||||
The full name of the kx509 client principal.
|
||||
.It principal-name-without-realm
|
||||
The full name of the kx509 client principal, excluding the realm name.
|
||||
.It principal-name-realm
|
||||
The name of the client principal's realm.
|
||||
.It principal-component0
|
||||
The first component of the client principal.
|
||||
.It principal-component1
|
||||
The second component of the client principal.
|
||||
.It principal-component2
|
||||
The third component of the client principal.
|
||||
.It principal-service-name
|
||||
The name of the service.
|
||||
.It principal-host-name
|
||||
The name of the host.
|
||||
.El
|
||||
.El
|
||||
The
|
||||
.Li kx509 ,
|
||||
|
||||
@@ -386,7 +386,10 @@ typedef struct krb5_cccol_cursor_data *krb5_cccol_cursor;
|
||||
typedef struct krb5_ccache_data {
|
||||
const struct krb5_cc_ops *ops;
|
||||
krb5_data data;
|
||||
int initialized; /* if non-zero: krb5_cc_initialize() called, now empty */
|
||||
unsigned int cc_initialized:1; /* if 1: krb5_cc_initialize() called */
|
||||
unsigned int cc_need_start_realm:1;
|
||||
unsigned int cc_start_tgt_stored:1;
|
||||
unsigned int cc_kx509_done:1;
|
||||
}krb5_ccache_data;
|
||||
|
||||
typedef struct krb5_ccache_data *krb5_ccache;
|
||||
|
||||
796
lib/krb5/kx509.c
Normal file
796
lib/krb5/kx509.c
Normal file
@@ -0,0 +1,796 @@
|
||||
/*
|
||||
* Copyright (c) 2019 Kungliga Tekniska Högskolan
|
||||
* (Royal Institute of Technology, Stockholm, Sweden).
|
||||
* All rights reserved.
|
||||
*
|
||||
* Redistribution and use in source and binary forms, with or without
|
||||
* modification, are permitted provided that the following conditions
|
||||
* are met:
|
||||
*
|
||||
* 1. Redistributions of source code must retain the above copyright
|
||||
* notice, this list of conditions and the following disclaimer.
|
||||
*
|
||||
* 2. Redistributions in binary form must reproduce the above copyright
|
||||
* notice, this list of conditions and the following disclaimer in the
|
||||
* documentation and/or other materials provided with the distribution.
|
||||
*
|
||||
* 3. Neither the name of the Institute nor the names of its contributors
|
||||
* may be used to endorse or promote products derived from this software
|
||||
* without specific prior written permission.
|
||||
*
|
||||
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
|
||||
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
||||
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
||||
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
|
||||
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
||||
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
||||
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
||||
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
||||
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
||||
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
||||
* SUCH DAMAGE.
|
||||
*/
|
||||
|
||||
#include "krb5_locl.h"
|
||||
#include <kx509_asn1.h>
|
||||
#include <kx509_err.h>
|
||||
#include "../hx509/hx_locl.h" /* XXX find a better way */
|
||||
#include "hx509-private.h"
|
||||
|
||||
/*
|
||||
* This file implements a client for the kx509 protocol -- a Kerberized online
|
||||
* CA that can issue a Certificate to a client that authenticates using
|
||||
* Kerberos.
|
||||
*
|
||||
* The kx509 protocol is the inverse of PKINIT. Whereas PKINIT allows users
|
||||
* with PKIX credentials to acquire Kerberos credentials, the kx509 protocol
|
||||
* allows users with Kerberos credentials to acquire PKIX credentials.
|
||||
*
|
||||
* I.e., kx509 is a bridge, just like PKINIT.
|
||||
*
|
||||
* The kx509 protocol is very simple, and very limited.
|
||||
*
|
||||
* A request consists of a DER-encoded Kx509Request message prefixed with four
|
||||
* bytes identifying the protocol (see `version_2_0' below).
|
||||
*
|
||||
* A Kx509Request message contains an AP-REQ, a public key, and an HMAC of the
|
||||
* public key made with the session key of the AP-REQ's ticket.
|
||||
*
|
||||
* The service principal can be either kca_service/hostname.fqdn or
|
||||
* krbtgt/REALM (a Heimdal innovation).
|
||||
*
|
||||
* If a request is missing a public key, then the request is a probe intended
|
||||
* to discover whether the service is enabled, thus helping the client avoid
|
||||
* a possibly-slow private key generation operation.
|
||||
*
|
||||
* The response is a DER-encoded Kx509Response also prefixed with
|
||||
* `version_2_0', and contains: an optional error code and error text, an
|
||||
* optional certificate (for the success case), and an optional HMAC of those
|
||||
* fields that is present when the service was able to verify the AP-REQ.
|
||||
*
|
||||
* Limitations:
|
||||
*
|
||||
* - no proof of possession for the public key
|
||||
* - only RSA keys are supported
|
||||
* - no way to express options (e.g., what KUs, EKUs, or SANs are desired)
|
||||
* - no sub-session key usage
|
||||
* - no reflection protection other than the HMAC's forgery protection and the
|
||||
* fact that the client could tell that a reflected attack isn't success
|
||||
*
|
||||
* Future directions:
|
||||
*
|
||||
* - Since the public key field of the request is an OCTET STRING, we could
|
||||
* send a CSR, or even an expired certificate (possibly self-signed,
|
||||
* possibly one issued earlier) that can serve as a template.
|
||||
*
|
||||
* This solves the first three limitations, as it allows the client to
|
||||
* demonstrate proof of possession, allows arbitrary public key types, and
|
||||
* allows the client to express desires about the to-be-issued certificate.
|
||||
*
|
||||
* - Use the AP-REQ's Authenticator's sub-session key for the HMAC, and derive
|
||||
* per-direction sub-sub-keys.
|
||||
*
|
||||
* - We might design a new protocol that better fits the RFC4120 KDC message
|
||||
* framework.
|
||||
*/
|
||||
|
||||
static const unsigned char version_2_0[4] = {0 , 0, 2, 0};
|
||||
|
||||
struct kx509_ctx_data {
|
||||
char *send_to_realm; /* realm to which to send request */
|
||||
krb5_keyblock *hmac_key; /* For HMAC validation */
|
||||
hx509_private_key *keys;
|
||||
hx509_private_key priv_key;
|
||||
};
|
||||
|
||||
static krb5_error_code
|
||||
load_priv_key(krb5_context context,
|
||||
struct kx509_ctx_data *kx509_ctx,
|
||||
const char *fn)
|
||||
{
|
||||
hx509_private_key *keys = NULL;
|
||||
hx509_certs certs = NULL;
|
||||
krb5_error_code ret;
|
||||
|
||||
ret = hx509_certs_init(context->hx509ctx, fn, 0, NULL, &certs);
|
||||
if (ret == ENOENT)
|
||||
return 0;
|
||||
if (ret == 0)
|
||||
ret = _hx509_certs_keys_get(context->hx509ctx, certs, &keys);
|
||||
if (ret == 0 && keys[0] == NULL)
|
||||
ret = ENOENT;
|
||||
if (ret == 0)
|
||||
kx509_ctx->priv_key = _hx509_private_key_ref(keys[0]);
|
||||
if (ret)
|
||||
krb5_set_error_message(context, ret, "Could not load private key "
|
||||
"from %s for kx509: %s", fn,
|
||||
hx509_get_error_string(context->hx509ctx, ret));
|
||||
hx509_certs_free(&certs);
|
||||
return ret;
|
||||
}
|
||||
|
||||
static krb5_error_code
|
||||
gen_priv_key(krb5_context context,
|
||||
const char *gen_type,
|
||||
unsigned long gen_bits,
|
||||
hx509_private_key *key)
|
||||
{
|
||||
struct hx509_generate_private_context *key_gen_ctx = NULL;
|
||||
krb5_error_code ret;
|
||||
|
||||
_krb5_debug(context, 1, "kx509: gen priv key");
|
||||
if (strcmp(gen_type, "rsa")) {
|
||||
krb5_set_error_message(context, ENOTSUP, "Key type %s is not "
|
||||
"supported for kx509; only \"rsa\" is "
|
||||
"supported for kx509 at this time",
|
||||
gen_type);
|
||||
return ENOTSUP;
|
||||
}
|
||||
|
||||
ret = _hx509_generate_private_key_init(context->hx509ctx,
|
||||
ASN1_OID_ID_PKCS1_RSAENCRYPTION,
|
||||
&key_gen_ctx);
|
||||
if (ret == 0)
|
||||
ret = _hx509_generate_private_key_bits(context->hx509ctx, key_gen_ctx, gen_bits);
|
||||
|
||||
if (ret == 0)
|
||||
ret = _hx509_generate_private_key(context->hx509ctx, key_gen_ctx, key);
|
||||
_hx509_generate_private_key_free(&key_gen_ctx);
|
||||
if (ret)
|
||||
krb5_set_error_message(context, ret,
|
||||
"Could not generate a private key: %s",
|
||||
hx509_get_error_string(context->hx509ctx, ret));
|
||||
return ret;
|
||||
}
|
||||
|
||||
/* Set a cc config entry indicating that the kx509 service is not available */
|
||||
static void
|
||||
store_kx509_disabled(krb5_context context, const char *realm, krb5_ccache cc)
|
||||
{
|
||||
krb5_data data;
|
||||
|
||||
if (!cc)
|
||||
return;
|
||||
|
||||
data.data = (void *)(uintptr_t)realm;
|
||||
data.length = strlen(realm);
|
||||
krb5_cc_set_config(context, cc, NULL, "kx509_service_realm", &data);
|
||||
data.data = "disabled";
|
||||
data.length = strlen(data.data);
|
||||
krb5_cc_set_config(context, cc, NULL, "kx509_service_status", &data);
|
||||
}
|
||||
|
||||
/* Store the private key and certificate where requested */
|
||||
static krb5_error_code
|
||||
store(krb5_context context,
|
||||
const char *hx509_store,
|
||||
const char *realm,
|
||||
krb5_ccache cc,
|
||||
hx509_private_key key,
|
||||
hx509_cert cert)
|
||||
{
|
||||
heim_octet_string hdata;
|
||||
krb5_error_code ret = 0;
|
||||
krb5_data data;
|
||||
|
||||
krb5_clear_error_message(context);
|
||||
|
||||
if (cc) {
|
||||
/* Record the realm we used */
|
||||
data.data = (void *)(uintptr_t)realm;
|
||||
data.length = strlen(realm);
|
||||
krb5_cc_set_config(context, cc, NULL, "kx509_service_realm", &data);
|
||||
|
||||
/* Serialize and store the certificate in the ccache */
|
||||
ret = hx509_cert_binary(context->hx509ctx, cert, &hdata);
|
||||
data.data = hdata.data;
|
||||
data.length = hdata.length;
|
||||
if (ret == 0)
|
||||
ret = krb5_cc_set_config(context, cc, NULL, "kx509cert", &data);
|
||||
free(hdata.data);
|
||||
|
||||
/*
|
||||
* Serialized and store the key in the ccache. Use PKCS#8 so that we
|
||||
* store the algorithm OID too, which is needed in order to be able to
|
||||
* read the private key back.
|
||||
*/
|
||||
if (ret == 0)
|
||||
ret = _hx509_private_key_export(context->hx509ctx, key,
|
||||
HX509_KEY_FORMAT_PKCS8, &hdata);
|
||||
data.data = hdata.data;
|
||||
data.length = hdata.length;
|
||||
if (ret == 0)
|
||||
ret = krb5_cc_set_config(context, cc, NULL, "kx509key", &data);
|
||||
free(hdata.data);
|
||||
if (ret)
|
||||
krb5_set_error_message(context, ret, "Could not store kx509 "
|
||||
"private key and certificate in ccache %s",
|
||||
krb5_cc_get_name(context, cc));
|
||||
}
|
||||
|
||||
|
||||
/* Store the private key and cert in an hx509 store */
|
||||
if (hx509_store != NULL) {
|
||||
hx509_certs certs;
|
||||
|
||||
_hx509_cert_assign_key(cert, key); /* store both in the same store */
|
||||
|
||||
ret = hx509_certs_init(context->hx509ctx, hx509_store,
|
||||
HX509_CERTS_CREATE, NULL, &certs);
|
||||
if (ret == 0)
|
||||
ret = hx509_certs_add(context->hx509ctx, certs, cert);
|
||||
if (ret == 0)
|
||||
ret = hx509_certs_store(context->hx509ctx, certs, 0, NULL);
|
||||
hx509_certs_free(&certs);
|
||||
if (ret)
|
||||
krb5_prepend_error_message(context, ret, "Could not store kx509 "
|
||||
"private key and certificate in key "
|
||||
"store %s", hx509_store);
|
||||
}
|
||||
|
||||
/* Store the name of the hx509 store in the ccache too */
|
||||
if (cc && hx509_store) {
|
||||
data.data = (void *)(uintptr_t)hx509_store;
|
||||
data.length = strlen(hx509_store);
|
||||
(void) krb5_cc_set_config(context, cc, NULL, "kx509store", &data);
|
||||
}
|
||||
return ret;
|
||||
}
|
||||
|
||||
static void
|
||||
init_kx509_ctx(struct kx509_ctx_data *ctx)
|
||||
{
|
||||
memset(ctx, 0, sizeof(*ctx));
|
||||
ctx->send_to_realm = NULL;
|
||||
ctx->hmac_key = NULL;
|
||||
ctx->keys = NULL;
|
||||
ctx->priv_key = NULL;
|
||||
}
|
||||
|
||||
static void
|
||||
free_kx509_ctx(krb5_context context, struct kx509_ctx_data *ctx)
|
||||
{
|
||||
krb5_free_keyblock(context, ctx->hmac_key);
|
||||
free(ctx->send_to_realm);
|
||||
hx509_private_key_free(&ctx->priv_key);
|
||||
if (ctx->keys)
|
||||
_hx509_certs_keys_free(context->hx509ctx, ctx->keys);
|
||||
init_kx509_ctx(ctx);
|
||||
}
|
||||
|
||||
/*
|
||||
* Make a request, which is a DER-encoded Kx509Request with version_2_0
|
||||
* prefixed to it.
|
||||
*
|
||||
* If no private key is given, then a probe request will be made.
|
||||
*/
|
||||
static krb5_error_code
|
||||
mk_kx509_req(krb5_context context,
|
||||
struct kx509_ctx_data *kx509_ctx,
|
||||
krb5_ccache incc,
|
||||
const char *realm,
|
||||
hx509_private_key private_key,
|
||||
krb5_data *req)
|
||||
{
|
||||
unsigned char digest[SHA_DIGEST_LENGTH];
|
||||
SubjectPublicKeyInfo spki;
|
||||
struct Kx509Request kx509_req;
|
||||
krb5_data pre_req;
|
||||
krb5_auth_context ac = NULL;
|
||||
krb5_error_code ret = 0;
|
||||
krb5_creds this_cred;
|
||||
krb5_creds *cred = NULL;
|
||||
HMAC_CTX ctx;
|
||||
const char *hostname;
|
||||
size_t len;
|
||||
|
||||
krb5_data_zero(&pre_req);
|
||||
memset(&spki, 0, sizeof(spki));
|
||||
memset(&this_cred, 0, sizeof(this_cred));
|
||||
memset(&kx509_req, 0, sizeof(kx509_req));
|
||||
kx509_req.pk_hash.data = digest;
|
||||
kx509_req.pk_hash.length = SHA_DIGEST_LENGTH;
|
||||
|
||||
if (private_key) {
|
||||
/* Encode the public key for use in the request */
|
||||
ret = hx509_private_key2SPKI(context->hx509ctx, private_key, &spki);
|
||||
kx509_req.pk_key.data = spki.subjectPublicKey.data;
|
||||
kx509_req.pk_key.length = spki.subjectPublicKey.length >> 3;
|
||||
} else {
|
||||
/* Probe */
|
||||
kx509_req.pk_key.data = NULL;
|
||||
kx509_req.pk_key.length = 0;
|
||||
}
|
||||
|
||||
if (ret == 0)
|
||||
ret = krb5_auth_con_init(context, &ac);
|
||||
if (ret == 0)
|
||||
ret = krb5_cc_get_principal(context, incc, &this_cred.client);
|
||||
if (ret == 0) {
|
||||
/*
|
||||
* The kx509 protocol as deployed uses kca_service/kdc_hostname, but
|
||||
* this is inconvenient in libkrb5: we want to be able to use the
|
||||
* send_to_kdc machinery, and since the Heimdal KDC is also the kx509
|
||||
* service, we want not to have to specify kx509 hosts separately from
|
||||
* KDCs.
|
||||
*
|
||||
* We'd much rather use krbtgt/CLIENT_REALM@REQUESTED_REALM. What
|
||||
* we do is assume all KDCs for `realm' support the kx509 service and
|
||||
* then sendto the KDCs for that realm while using a hostbased service
|
||||
* if still desired.
|
||||
*
|
||||
* Note that upstairs we try to get the start_realm cc config, so if
|
||||
* realm wasn't given to krb5_kx509_ext(), then it should be set to
|
||||
* that already unless there's no start_realm cc config, in which case
|
||||
* we'll use the ccache's default client principal's realm.
|
||||
*/
|
||||
realm = realm ? realm : this_cred.client->realm;
|
||||
hostname = krb5_config_get_string(context, NULL, "realm", realm,
|
||||
"kx509_hostname", NULL);
|
||||
if (hostname == NULL)
|
||||
hostname = krb5_config_get_string(context, NULL, "libdefaults",
|
||||
"kx509_hostname", NULL);
|
||||
if (hostname) {
|
||||
ret = krb5_sname_to_principal(context, hostname, "kca_service",
|
||||
KRB5_NT_SRV_HST, &this_cred.server);
|
||||
if (ret == 0)
|
||||
ret = krb5_principal_set_realm(context, this_cred.server,
|
||||
realm);
|
||||
} else {
|
||||
ret = krb5_make_principal(context, &this_cred.server, realm,
|
||||
KRB5_TGS_NAME, this_cred.client->realm,
|
||||
NULL);
|
||||
}
|
||||
}
|
||||
|
||||
/* Make the AP-REQ and extract the HMAC key */
|
||||
if (ret == 0)
|
||||
ret = krb5_get_credentials(context, 0, incc, &this_cred, &cred);
|
||||
if (ret == 0)
|
||||
ret = krb5_mk_req_extended(context, &ac, AP_OPTS_USE_SUBKEY, NULL, cred,
|
||||
&kx509_req.authenticator);
|
||||
krb5_free_keyblock(context, kx509_ctx->hmac_key);
|
||||
kx509_ctx->hmac_key = NULL;
|
||||
if (ret == 0)
|
||||
ret = krb5_auth_con_getkey(context, ac, &kx509_ctx->hmac_key);
|
||||
|
||||
/* Save the realm to send to */
|
||||
free(kx509_ctx->send_to_realm);
|
||||
kx509_ctx->send_to_realm = NULL;
|
||||
if (ret == 0 &&
|
||||
(kx509_ctx->send_to_realm =
|
||||
strdup(krb5_principal_get_realm(context, cred->server))) == NULL)
|
||||
ret = krb5_enomem(context);
|
||||
|
||||
if (ret)
|
||||
goto out;
|
||||
|
||||
/* Add the the key and HMAC to the message */
|
||||
HMAC_CTX_init(&ctx);
|
||||
HMAC_Init_ex(&ctx, kx509_ctx->hmac_key->keyvalue.data,
|
||||
kx509_ctx->hmac_key->keyvalue.length, EVP_sha1(), NULL);
|
||||
HMAC_Update(&ctx, version_2_0, sizeof(version_2_0));
|
||||
if (private_key) {
|
||||
HMAC_Update(&ctx, kx509_req.pk_key.data, kx509_req.pk_key.length);
|
||||
} else {
|
||||
/* Probe */
|
||||
HMAC_Update(&ctx, kx509_req.authenticator.data, kx509_req.authenticator.length);
|
||||
}
|
||||
HMAC_Final(&ctx, kx509_req.pk_hash.data, 0);
|
||||
HMAC_CTX_cleanup(&ctx);
|
||||
|
||||
/* Encode the message, prefix `version_2_0', output the result */
|
||||
ASN1_MALLOC_ENCODE(Kx509Request, pre_req.data, pre_req.length, &kx509_req, &len, ret);
|
||||
ret = krb5_data_alloc(req, pre_req.length + sizeof(version_2_0));
|
||||
if (ret == 0) {
|
||||
memcpy(req->data, version_2_0, sizeof(version_2_0));
|
||||
memcpy(((unsigned char *)req->data) + sizeof(version_2_0),
|
||||
pre_req.data, pre_req.length);
|
||||
}
|
||||
|
||||
out:
|
||||
free(pre_req.data);
|
||||
krb5_free_creds(context, cred);
|
||||
krb5_xfree(kx509_req.authenticator.data);
|
||||
free_SubjectPublicKeyInfo(&spki);
|
||||
krb5_free_cred_contents(context, &this_cred);
|
||||
krb5_auth_con_free(context, ac);
|
||||
if (ret == 0 && req->length != len + sizeof(version_2_0)) {
|
||||
krb5_data_free(req);
|
||||
krb5_set_error_message(context, ret = ERANGE,
|
||||
"Could not make a kx509 request");
|
||||
}
|
||||
return ret;
|
||||
}
|
||||
|
||||
/* Parse and validate a kx509 reply */
|
||||
static krb5_error_code
|
||||
rd_kx509_resp(krb5_context context,
|
||||
struct kx509_ctx_data *kx509_ctx,
|
||||
krb5_data *rep,
|
||||
hx509_cert *cert)
|
||||
{
|
||||
unsigned char digest[SHA_DIGEST_LENGTH];
|
||||
Kx509Response r;
|
||||
krb5_error_code code = 0;
|
||||
krb5_error_code ret = 0;
|
||||
heim_string_t hestr;
|
||||
heim_error_t herr = NULL;
|
||||
const char *estr;
|
||||
HMAC_CTX ctx;
|
||||
size_t hdr_len = sizeof(version_2_0);
|
||||
size_t len;
|
||||
|
||||
*cert = NULL;
|
||||
|
||||
/* Strip `version_2_0' prefix */
|
||||
if (rep->length < hdr_len || memcmp(rep->data, version_2_0, hdr_len)) {
|
||||
krb5_set_error_message(context, ENOTSUP,
|
||||
"KDC does not support kx509 protocol");
|
||||
return ENOTSUP; /* XXX */
|
||||
}
|
||||
|
||||
/* Decode */
|
||||
ret = decode_Kx509Response(((unsigned char *)rep->data) + 4,
|
||||
rep->length - 4, &r, &len);
|
||||
if (ret == 0 && len + hdr_len != rep->length)
|
||||
ret = EINVAL; /* XXX */
|
||||
if (ret) {
|
||||
krb5_set_error_message(context, ret, "kx509 response is not valid");
|
||||
return ret;
|
||||
}
|
||||
|
||||
HMAC_CTX_init(&ctx);
|
||||
HMAC_Init_ex(&ctx, kx509_ctx->hmac_key->keyvalue.data,
|
||||
kx509_ctx->hmac_key->keyvalue.length, EVP_sha1(), NULL);
|
||||
HMAC_Update(&ctx, version_2_0, sizeof(version_2_0));
|
||||
|
||||
{
|
||||
int32_t t = r.error_code;
|
||||
unsigned char encint[sizeof(t) + 1];
|
||||
size_t k;
|
||||
|
||||
/*
|
||||
* RFC6717 says this about how the error-code is included in the HMAC:
|
||||
*
|
||||
* o DER representation of the error-code exclusive of the tag and
|
||||
* length, if it is present.
|
||||
*
|
||||
* So we use der_put_integer(), which encodes from the right.
|
||||
*
|
||||
* RFC6717 does not constrain the error-code's range. We assume it to
|
||||
* be a 32-bit, signed integer, for which we'll need no more than 5
|
||||
* bytes.
|
||||
*/
|
||||
ret = der_put_integer(&encint[sizeof(encint) - 1],
|
||||
sizeof(encint), &t, &k);
|
||||
if (ret == 0)
|
||||
HMAC_Update(&ctx, &encint[sizeof(encint)] - k, k);
|
||||
|
||||
/* Normalize error code */
|
||||
if (r.error_code == 0) {
|
||||
code = 0; /* No error */
|
||||
} else if (r.error_code < 0) {
|
||||
code = KRB5KRB_ERR_GENERIC; /* ??? */
|
||||
} else if (r.error_code <= KX509_ERR_SRV_OVERLOADED) {
|
||||
/*
|
||||
* RFC6717 (kx509) error code. These are actually not used on the
|
||||
* wire in any existing implementations that we are aware of. Just
|
||||
* in case, however, we'll map these.
|
||||
*/
|
||||
code = KX509_ERR_CLNT_FATAL + r.error_code;
|
||||
} else if (r.error_code < kx509_krb5_error_base) {
|
||||
/* Unknown error codes */
|
||||
code = KRB5KRB_ERR_GENERIC;
|
||||
} else {
|
||||
/*
|
||||
* Heimdal-specific enhancement to RFC6171: Kerberos wire protocol
|
||||
* error codes.
|
||||
*/
|
||||
code = KRB5KDC_ERR_NONE + r.error_code - kx509_krb5_error_base;
|
||||
if (code >= KRB5_ERR_RCSID)
|
||||
code = KRB5KRB_ERR_GENERIC;
|
||||
if (code == KRB5KDC_ERR_NONE)
|
||||
code = 0;
|
||||
}
|
||||
}
|
||||
if (r.certificate)
|
||||
HMAC_Update(&ctx, r.certificate->data, r.certificate->length);
|
||||
if (r.e_text)
|
||||
HMAC_Update(&ctx, *r.e_text, strlen(*r.e_text));
|
||||
HMAC_Final(&ctx, &digest, 0);
|
||||
HMAC_CTX_cleanup(&ctx);
|
||||
|
||||
if (r.hash == NULL) {
|
||||
/*
|
||||
* No HMAC -> unauthenticated [error] response.
|
||||
*
|
||||
* Do not output any certificate.
|
||||
*/
|
||||
free_Kx509Response(&r);
|
||||
return code;
|
||||
}
|
||||
|
||||
/*
|
||||
* WARNING: We do not validate that `r.certificate' is a DER-encoded
|
||||
* Certificate, not here, and we don't use a different HMAC key
|
||||
* for the response than for the request.
|
||||
*
|
||||
* If ever we start sending a Certificate as the Kx509Request
|
||||
* pk-key field, then we'll have a reflection attack. As the
|
||||
* Certificate we'd send in that case will be expired, the
|
||||
* reflection attack would be just a DoS.
|
||||
*/
|
||||
if (r.hash->length != sizeof(digest) ||
|
||||
ct_memcmp(r.hash->data, digest, sizeof(digest)) != 0) {
|
||||
krb5_set_error_message(context, KRB5KDC_ERR_PREAUTH_FAILED,
|
||||
"kx509 response MAC mismatch");
|
||||
free_Kx509Response(&r);
|
||||
return KRB5KRB_AP_ERR_BAD_INTEGRITY;
|
||||
}
|
||||
|
||||
if (r.certificate == NULL) {
|
||||
/* Authenticated response, either an error or probe success */
|
||||
free_Kx509Response(&r);
|
||||
if (code != KRB5KDC_ERR_POLICY && kx509_ctx->priv_key == NULL)
|
||||
return 0; /* Probe success */
|
||||
return code;
|
||||
}
|
||||
|
||||
/* Import the certificate payload */
|
||||
*cert = hx509_cert_init_data(context->hx509ctx, r.certificate->data,
|
||||
r.certificate->length, &herr);
|
||||
free_Kx509Response(&r);
|
||||
if (cert) {
|
||||
heim_release(herr);
|
||||
return 0;
|
||||
}
|
||||
|
||||
hestr = herr ? heim_error_copy_string(herr) : NULL;
|
||||
estr = hestr ? heim_string_get_utf8(hestr) : "(no error message)";
|
||||
krb5_set_error_message(context, ret, "Could not parse certificate "
|
||||
"produced by kx509 KDC: %s (%ld)",
|
||||
estr,
|
||||
herr ? (long)heim_error_get_code(herr) : 0L);
|
||||
|
||||
heim_release(hestr);
|
||||
heim_release(herr);
|
||||
return HEIM_PKINIT_CERTIFICATE_INVALID; /* XXX */
|
||||
}
|
||||
|
||||
/*
|
||||
* Make a request, send it, get the response, parse it, and store the
|
||||
* private key and certificate.
|
||||
*/
|
||||
static krb5_error_code
|
||||
kx509_core(krb5_context context,
|
||||
struct kx509_ctx_data *kx509_ctx,
|
||||
krb5_ccache incc,
|
||||
const char *realm,
|
||||
const char *hx509_store,
|
||||
krb5_ccache outcc)
|
||||
{
|
||||
krb5_error_code ret;
|
||||
hx509_cert cert = NULL;
|
||||
krb5_data req, resp;
|
||||
|
||||
krb5_data_zero(&req);
|
||||
krb5_data_zero(&resp);
|
||||
|
||||
/* Make the kx509 request */
|
||||
ret = mk_kx509_req(context, kx509_ctx, incc, realm, kx509_ctx->priv_key,
|
||||
&req);
|
||||
|
||||
/* Send the kx509 request and get the response */
|
||||
if (ret == 0)
|
||||
ret = krb5_sendto_context(context, NULL, &req,
|
||||
kx509_ctx->send_to_realm, &resp);
|
||||
if (ret == 0)
|
||||
ret = rd_kx509_resp(context, kx509_ctx, &resp, &cert);
|
||||
|
||||
/* Store the key and cert! */
|
||||
if (ret == 0 && kx509_ctx->priv_key)
|
||||
ret = store(context, hx509_store, kx509_ctx->send_to_realm, outcc,
|
||||
kx509_ctx->priv_key, cert);
|
||||
else if (ret == KRB5KDC_ERR_POLICY || ret == KRB5_KDC_UNREACH)
|
||||
/* Probe failed -> Record that the realm does not support kx509 */
|
||||
store_kx509_disabled(context, kx509_ctx->send_to_realm, outcc);
|
||||
|
||||
hx509_cert_free(cert);
|
||||
krb5_data_free(&resp);
|
||||
krb5_data_free(&req);
|
||||
return ret;
|
||||
}
|
||||
|
||||
/**
|
||||
* Use the kx509 v2 protocol to get a certificate for the client principal.
|
||||
*
|
||||
* Given a private key this function will get a certificate. If no private key
|
||||
* is given, one will be generated.
|
||||
*
|
||||
* The private key and certificate will be stored in the given hx509 store
|
||||
* (e.g, "PEM-FILE:/path/to/file.pem") and/or given output ccache. When stored
|
||||
* in a ccache, the DER-encoded Certificate will be stored as the data payload
|
||||
* of a "cc config" named "kx509cert", while the key will be stored as a
|
||||
* DER-encoded PKCS#8 PrivateKeyInfo in a cc config named "kx509key".
|
||||
*
|
||||
* @param context The Kerberos library context
|
||||
* @param incc A credential cache
|
||||
* @param realm A realm from which to get the certificate (uses the client
|
||||
* principal's realm if NULL)
|
||||
* @param use_priv_key_store An hx509 store containing a private key to certify
|
||||
* (if NULL, a key will be generated)
|
||||
* @param gen_type The public key algorithm for which to generate a private key
|
||||
* @param gen_bits The size of the public key to generate, in bits
|
||||
* @param hx509_store An hx509 store into which to store the private key and
|
||||
* certificate (e.g, "PEM-FILE:/path/to/file.pem")
|
||||
* @param outcc A ccache into which to store the private key and certificate
|
||||
*
|
||||
* @return A krb5 error code.
|
||||
*/
|
||||
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
|
||||
krb5_kx509_ext(krb5_context context,
|
||||
krb5_ccache incc,
|
||||
const char *realm,
|
||||
const char *use_priv_key_store,
|
||||
const char *gen_type,
|
||||
int gen_bits,
|
||||
const char *hx509_store,
|
||||
krb5_ccache outcc)
|
||||
{
|
||||
struct kx509_ctx_data kx509_ctx;
|
||||
krb5_error_code ret;
|
||||
char *freeme = NULL;
|
||||
|
||||
/* TODO: Eventually switch to ECDSA, and eventually to ed25519 or ed448 */
|
||||
if (gen_type == NULL) {
|
||||
gen_type = krb5_config_get_string_default(context, NULL, "rsa",
|
||||
"libdefaults",
|
||||
"kx509_gen_key_type", NULL);
|
||||
}
|
||||
|
||||
if (gen_bits == 0) {
|
||||
/*
|
||||
* The key size is really only for non-ECC, of which we'll only support
|
||||
* RSA. For ECC key sizes will either be implied by the `key_type' or
|
||||
* will have to be a magic value that allows us to pick from some small
|
||||
* set of curves (e.g., 255 == Curve25519).
|
||||
*/
|
||||
gen_bits = krb5_config_get_int_default(context, NULL, 2048,
|
||||
"libdefaults",
|
||||
"kx509_gen_rsa_key_size", NULL);
|
||||
}
|
||||
|
||||
init_kx509_ctx(&kx509_ctx);
|
||||
|
||||
if (realm == NULL) {
|
||||
krb5_data data;
|
||||
|
||||
ret = krb5_cc_get_config(context, incc, NULL, "start_realm", &data);
|
||||
if (ret == 0) {
|
||||
if ((freeme = strndup(data.data, data.length)) == NULL)
|
||||
return krb5_enomem(context);
|
||||
realm = freeme;
|
||||
}
|
||||
}
|
||||
|
||||
if (use_priv_key_store) {
|
||||
/* Get the given private key if it exists, and use it */
|
||||
ret = load_priv_key(context, &kx509_ctx, use_priv_key_store);
|
||||
if (ret == 0) {
|
||||
ret = kx509_core(context, &kx509_ctx, incc, realm, hx509_store,
|
||||
outcc);
|
||||
free_kx509_ctx(context, &kx509_ctx);
|
||||
free(freeme);
|
||||
return ret;
|
||||
}
|
||||
if (ret != ENOENT) {
|
||||
free_kx509_ctx(context, &kx509_ctx);
|
||||
free(freeme);
|
||||
return ret;
|
||||
}
|
||||
/* Key store doesn't exist or has no keys, fall through */
|
||||
}
|
||||
|
||||
/*
|
||||
* No private key given, so we generate one.
|
||||
*
|
||||
* However, before taking the hit for generating a keypair we probe to see
|
||||
* if we're likely to succeeed.
|
||||
*/
|
||||
|
||||
/* Probe == call kx509_core() w/o a private key */
|
||||
ret = kx509_core(context, &kx509_ctx, incc, realm, NULL, outcc);
|
||||
if (ret == 0)
|
||||
ret = gen_priv_key(context, gen_type, gen_bits, &kx509_ctx.priv_key);
|
||||
if (ret == 0)
|
||||
ret = kx509_core(context, &kx509_ctx, incc, realm, hx509_store, outcc);
|
||||
free_kx509_ctx(context, &kx509_ctx);
|
||||
free(freeme);
|
||||
return ret;
|
||||
}
|
||||
|
||||
/**
|
||||
* Generates a public key and uses the kx509 v2 protocol to get a certificate
|
||||
* for that key and the client principal's subject name.
|
||||
*
|
||||
* The private key and certificate will be stored in the given ccache, and also
|
||||
* in a corresponding hx509 store if one is configured via [libdefaults]
|
||||
* kx509_store.
|
||||
*
|
||||
* XXX NOTE: Dicey feature here... Review carefully!
|
||||
*
|
||||
* @param context The Kerberos library context
|
||||
* @param cc A credential cache
|
||||
* @param realm A realm from which to get the certificate (uses the client
|
||||
* principal's realm if NULL)
|
||||
*
|
||||
* @return A krb5 error code.
|
||||
*/
|
||||
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
|
||||
krb5_kx509(krb5_context context, krb5_ccache cc, const char *realm)
|
||||
{
|
||||
krb5_error_code ret = 0;
|
||||
const char *defcc;
|
||||
char *ccache_full_name = NULL;
|
||||
char *store_exp = NULL;
|
||||
|
||||
/*
|
||||
* The idea is that IF we are asked to do kx509 w/ creds from a default
|
||||
* ccache THEN we should store the kx509 certificate (if we get one) and
|
||||
* private key in the default hx509 store for kx509.
|
||||
*
|
||||
* Ideally we could have HTTP user-agents and/or TLS libraries look for
|
||||
* client certificates and private keys in that default hx509 store.
|
||||
*
|
||||
* Of course, those user-agents / libraries should be configured to use
|
||||
* those credentials with specific hostnames/domainnames, not the entire
|
||||
* Internet, as the latter leaks the user's identity to the world.
|
||||
*
|
||||
* So we check if the full name for `cc' is the same as that of the default
|
||||
* ccache name, and if so we get the [libdefaults] kx509_store string and
|
||||
* expand it, then use it.
|
||||
*/
|
||||
if ((defcc = krb5_cc_configured_default_name(context)) &&
|
||||
krb5_cc_get_full_name(context, cc, &ccache_full_name) == 0 &&
|
||||
strcmp(defcc, ccache_full_name) == 0) {
|
||||
|
||||
/* Find an hx509 store */
|
||||
const char *store = krb5_config_get_string(context, NULL,
|
||||
"libdefaults",
|
||||
"kx509_store", NULL);
|
||||
if (store)
|
||||
ret = _krb5_expand_path_tokens(context, store, 1, &store_exp);
|
||||
}
|
||||
|
||||
/*
|
||||
* If we did settle on a default hx509 store, we'll use it for reading the
|
||||
* private key from (if it exists) as well as for storing the certificate
|
||||
* (and private key) into, which may save us some key generation cycles.
|
||||
*/
|
||||
ret = krb5_kx509_ext(context, cc, realm, store_exp, NULL, 0,
|
||||
store_exp, cc);
|
||||
free(ccache_full_name);
|
||||
free(store_exp);
|
||||
return ret;
|
||||
}
|
||||
39
lib/krb5/kx509_err.et
Normal file
39
lib/krb5/kx509_err.et
Normal file
@@ -0,0 +1,39 @@
|
||||
#
|
||||
# Error messages for the krb5 library
|
||||
#
|
||||
# This might look like a com_err file, but is not
|
||||
#
|
||||
|
||||
# RFC6171 says:
|
||||
#
|
||||
# +------------+-----------------------------+------------------------+
|
||||
# | error-code | Condition | Example |
|
||||
# +------------+-----------------------------+------------------------+
|
||||
# | 1 | Permanent problem with | Incompatible version |
|
||||
# | | client request | |
|
||||
# | 2 | Solvable problem with | Expired Kerberos |
|
||||
# | | client request | credentials |
|
||||
# | 3 | Temporary problem with | Packet loss |
|
||||
# | | client request | |
|
||||
# | 4 | Permanent problem with the | Internal |
|
||||
# | | server | misconfiguration |
|
||||
# | 5 | Temporary problem with the | Server overloaded |
|
||||
# | | server | |
|
||||
# +------------+-----------------------------+------------------------+
|
||||
#
|
||||
# Error 3 makes no sense on the wire, and in the library it only makes sense as
|
||||
# a timeout, so we'll name it KX509_ERR_TIMEOUT.
|
||||
|
||||
# Error table names must be no more than four characters...
|
||||
error_table kx59
|
||||
|
||||
prefix KX509_ERR
|
||||
|
||||
error_code NONE, "Kx509 success"
|
||||
error_code CLNT_FATAL, "Kx509 request error, possibly unsupported version"
|
||||
error_code CLNT_SOLVABLE, "Kx509 request error such as expired credentials"
|
||||
error_code TIMEOUT, "Kx509 request timed out"
|
||||
error_code SRV_FATAL, "Permanent server problem"
|
||||
error_code SRV_OVERLOADED, "Kx509 server is overloaded"
|
||||
|
||||
end
|
||||
@@ -438,6 +438,8 @@ EXPORTS
|
||||
krb5_kt_resolve
|
||||
krb5_kt_start_seq_get
|
||||
krb5_kuserok
|
||||
krb5_kx509
|
||||
krb5_kx509_ext
|
||||
krb5_log
|
||||
krb5_log_msg
|
||||
krb5_make_addrport
|
||||
|
||||
@@ -431,6 +431,8 @@ HEIMDAL_KRB5_2.0 {
|
||||
krb5_kt_resolve;
|
||||
krb5_kt_start_seq_get;
|
||||
krb5_kuserok;
|
||||
krb5_kx509;
|
||||
krb5_kx509_ext;
|
||||
krb5_log;
|
||||
krb5_log_msg;
|
||||
krb5_make_addrport;
|
||||
|
||||
@@ -2,6 +2,8 @@ include @srcdirabs@/include-krb5.conf
|
||||
|
||||
[libdefaults]
|
||||
default_keytab_name = @objdir@/server.keytab
|
||||
enable-kx509 = yes
|
||||
kx509_store = PEM-FILE:/tmp/cert_%{euid}.pem
|
||||
|
||||
[realms]
|
||||
TEST.H5L.SE = {
|
||||
|
||||
@@ -232,6 +232,11 @@ krb5-pkinit-win.conf: krb5-pkinit.conf.in Makefile
|
||||
|
||||
CLEANFILES= \
|
||||
$(TESTS) \
|
||||
*.crt \
|
||||
*.der \
|
||||
*.log \
|
||||
*.pem \
|
||||
*.pid \
|
||||
*.tmp \
|
||||
acache.krb5 \
|
||||
barpassword \
|
||||
@@ -239,7 +244,6 @@ CLEANFILES= \
|
||||
cache.krb5 \
|
||||
cdigest-reply \
|
||||
client-cache \
|
||||
current*.log \
|
||||
current-db* \
|
||||
digest-reply \
|
||||
foopassword \
|
||||
@@ -248,7 +252,6 @@ CLEANFILES= \
|
||||
iprop.keytab \
|
||||
ipropd.dumpfile \
|
||||
kdc-tester4.json \
|
||||
kdc.crt \
|
||||
krb5-authz.conf \
|
||||
krb5-authz2.conf \
|
||||
krb5-canon.conf \
|
||||
@@ -267,18 +270,11 @@ CLEANFILES= \
|
||||
malloc-log \
|
||||
malloc-log-master \
|
||||
malloc-log-slave \
|
||||
messages.log \
|
||||
notfoopassword \
|
||||
o2cache.krb5 \
|
||||
o2digest-reply \
|
||||
ocache.krb5 \
|
||||
out-log \
|
||||
pkinit.crt \
|
||||
pkinit2.crt \
|
||||
pkinit3.crt \
|
||||
pkinit4.crt \
|
||||
req-kdc.der \
|
||||
req-pkinit.der \
|
||||
req-pkinit2.der \
|
||||
s2digest-reply \
|
||||
sdigest-init \
|
||||
sdigest-reply \
|
||||
|
||||
@@ -55,9 +55,14 @@ keyfile="${hx509_data}/key.der"
|
||||
keyfile2="${hx509_data}/key2.der"
|
||||
|
||||
kinit="${kinit} -c $cache ${afs_no_afslog}"
|
||||
klist="${klist} --hidden -v -c $cache"
|
||||
kgetcred="${kgetcred} -c $cache"
|
||||
kdestroy="${kdestroy} -c $cache ${afs_no_unlog}"
|
||||
|
||||
kextract() {
|
||||
${klist} --extract-kx509-cert="$1"
|
||||
}
|
||||
|
||||
KRB5_CONFIG="${objdir}/krb5-pkinit.conf"
|
||||
export KRB5_CONFIG
|
||||
|
||||
@@ -104,6 +109,13 @@ ${kadmin} add -p kaka --use-defaults ${server}@${R} || exit 1
|
||||
echo "Doing database check"
|
||||
${kadmin} check ${R} || exit 1
|
||||
|
||||
# XXX Do not use committed, in-tree private keys or certificates!
|
||||
# XXX Add hxtool command to generate a private key w/o generating a CSR
|
||||
# XXX Use hxtool to generate a fresh private key
|
||||
# XXX Use hxtool to generate self-signed CA certs
|
||||
# XXX Use PEM-FILE and store private key and certificate in same file
|
||||
# XXX Update krb5.conf.in to use ${objdir}-relative keys and certificates
|
||||
|
||||
echo "Setting up certificates"
|
||||
${hxtool} request-create \
|
||||
--subject="CN=kdc,DC=test,DC=h5l,DC=se" \
|
||||
@@ -165,6 +177,12 @@ ${hxtool} issue-certificate \
|
||||
--req="PKCS10:req-pkinit2.der" \
|
||||
--certificate="FILE:pkinit4.crt" || exit 1
|
||||
|
||||
echo "issue self-signed kx509 template cert"
|
||||
${hxtool} issue-certificate \
|
||||
--self-signed \
|
||||
--ca-private-key=FILE:${keyfile} \
|
||||
--subject='CN=${principal-component0},DC=test,DC=h5l,DC=se' \
|
||||
--certificate="FILE:kx509-template.crt" || exit 1
|
||||
|
||||
echo foo > ${objdir}/foopassword
|
||||
|
||||
@@ -181,8 +199,16 @@ base="${objdir}"
|
||||
${kinit} -C FILE:${base}/pkinit.crt,${keyfile2} bar@${R} || \
|
||||
{ ec=1 ; eval "${testfailed}"; }
|
||||
${kgetcred} ${server}@${R} || { ec=1 ; eval "${testfailed}"; }
|
||||
${klist}
|
||||
|
||||
echo "Check kx509 certificate acquisition"
|
||||
kextract PEM-FILE:${objdir}/kx509.pem || { ec=1 ; eval "${testfailed}"; }
|
||||
${kdestroy}
|
||||
|
||||
echo "Check PKINIT w/ kx509 certificate"
|
||||
${kinit} -C PEM-FILE:${objdir}/kx509.pem bar@${R} || \
|
||||
{ ec=1 ; eval "${testfailed}"; }
|
||||
|
||||
echo "Trying pk-init (principal in pki-mapping file) "; > messages.log
|
||||
${kinit} -C FILE:${base}/pkinit.crt,${keyfile2} foo@${R} || \
|
||||
{ ec=1 ; eval "${testfailed}"; }
|
||||
|
||||
@@ -19,6 +19,14 @@
|
||||
pkinit_anchors = FILE:@objdir@/ca.crt
|
||||
pkinit_mappings_file = @srcdir@/pki-mapping
|
||||
|
||||
enable-kx509 = true
|
||||
kx509_include_email_san = true
|
||||
kx509_include_pkinit_san = true
|
||||
kx509_include_dnsname_san = true
|
||||
require_initial_kca_tickets = false
|
||||
kx509_template = FILE:@objdir@/kx509-template.crt
|
||||
kx509_ca = FILE:@objdir@/ca.crt,@srcdir@/../../lib/hx509/data/key.der
|
||||
|
||||
database = {
|
||||
dbname = @objdir@/current-db
|
||||
realm = TEST.H5L.SE
|
||||
|
||||
Reference in New Issue
Block a user