1=pod
2
3=head1 NAME
4
5OSSL_CMP_exec_certreq,
6OSSL_CMP_exec_IR_ses,
7OSSL_CMP_exec_CR_ses,
8OSSL_CMP_exec_P10CR_ses,
9OSSL_CMP_exec_KUR_ses,
10OSSL_CMP_IR,
11OSSL_CMP_CR,
12OSSL_CMP_P10CR,
13OSSL_CMP_KUR,
14OSSL_CMP_try_certreq,
15OSSL_CMP_exec_RR_ses,
16OSSL_CMP_exec_GENM_ses
17- functions implementing CMP client transactions
18
19=head1 SYNOPSIS
20
21 #include <openssl/cmp.h>
22
23 X509 *OSSL_CMP_exec_certreq(OSSL_CMP_CTX *ctx, int req_type,
24                             const OSSL_CRMF_MSG *crm);
25 X509 *OSSL_CMP_exec_IR_ses(OSSL_CMP_CTX *ctx);
26 X509 *OSSL_CMP_exec_CR_ses(OSSL_CMP_CTX *ctx);
27 X509 *OSSL_CMP_exec_P10CR_ses(OSSL_CMP_CTX *ctx);
28 X509 *OSSL_CMP_exec_KUR_ses(OSSL_CMP_CTX *ctx);
29 #define OSSL_CMP_IR
30 #define OSSL_CMP_CR
31 #define OSSL_CMP_P10CR
32 #define OSSL_CMP_KUR
33 int OSSL_CMP_try_certreq(OSSL_CMP_CTX *ctx, int req_type,
34                          const OSSL_CRMF_MSG *crm, int *checkAfter);
35 int OSSL_CMP_exec_RR_ses(OSSL_CMP_CTX *ctx);
36 STACK_OF(OSSL_CMP_ITAV) *OSSL_CMP_exec_GENM_ses(OSSL_CMP_CTX *ctx);
37
38=head1 DESCRIPTION
39
40This is the OpenSSL API for doing CMP (Certificate Management Protocol)
41client-server transactions, i.e., sequences of CMP requests and responses.
42
43All functions take a populated OSSL_CMP_CTX structure as their first argument.
44Usually the server name, port, and path ("CMP alias") need to be set, as well as
45credentials the client can use for authenticating itself to the client.
46In order to authenticate the server the client typically needs a trust store.
47The functions return their respective main results directly, while there are
48also accessor functions for retrieving various results and status information
49from the I<ctx>. See L<OSSL_CMP_CTX_new(3)> etc. for details.
50
51The default conveying protocol is HTTP.
52Timeout values may be given per request-response pair and per transaction.
53See L<OSSL_CMP_MSG_http_perform(3)> for details.
54
55OSSL_CMP_exec_IR_ses() requests an initial certificate from the given PKI.
56
57OSSL_CMP_exec_CR_ses() requests an additional certificate.
58
59OSSL_CMP_exec_P10CR_ses() conveys a legacy PKCS#10 CSR requesting a certificate.
60
61OSSL_CMP_exec_KUR_ses() obtains an updated certificate.
62
63These four types of certificate enrollment are implemented as macros
64calling OSSL_CMP_exec_certreq().
65
66OSSL_CMP_exec_certreq() performs a certificate request of the type specified
67by the I<req_type> parameter, which may be IR, CR, P10CR, or KUR.
68For IR, CR, and KUR, the certificate template to be used in the request
69may be supplied via the I<crm> parameter pointing to a CRMF structure.
70Typically I<crm> is NULL, then the template ingredients are taken from I<ctx>
71and need to be filled in using L<OSSL_CMP_CTX_set1_subjectName(3)>,
72L<OSSL_CMP_CTX_set0_newPkey(3)>, L<OSSL_CMP_CTX_set1_oldCert(3)>, etc.
73For P10CR, L<OSSL_CMP_CTX_set1_p10CSR(3)> needs to be used instead.
74The enrollment session may be blocked by sleeping until the addressed
75CA (or an intermedate PKI component) can fully process and answer the request.
76
77OSSL_CMP_try_certreq() is an alternative to the above functions that is
78more flexible regarding what to do after receiving a checkAfter value.
79When called for the first time (with no certificate request in progress for
80the given I<ctx>) it starts a new transaction by sending a certificate request
81constructed as stated above using the I<req_type> and optional I<crm> parameter.
82Otherwise (when according to I<ctx> a 'waiting' status has been received before)
83it continues polling for the pending request
84unless the I<req_type> argument is < 0, which aborts the request.
85If the requested certificate is available the function returns 1 and the
86caller can use L<OSSL_CMP_CTX_get0_newCert(3)> to retrieve the new certificate.
87If no error occurred but no certificate is available yet then
88OSSL_CMP_try_certreq() remembers in the CMP context that it should be retried
89and returns -1 after assigning the received checkAfter value
90via the output pointer argument (unless it is NULL).
91The checkAfter value indicates the number of seconds the caller should let pass
92before trying again. The caller is free to sleep for the given number of seconds
93or for some other time and/or to do anything else before retrying by calling
94OSSL_CMP_try_certreq() again with the same parameter values as before.
95OSSL_CMP_try_certreq() then polls
96to see whether meanwhile the requested certificate is available.
97If the caller decides to abort the pending certificate request and provides
98a negative value as the I<req_type> argument then OSSL_CMP_try_certreq()
99aborts the CMP transaction by sending an error message to the server.
100
101OSSL_CMP_exec_RR_ses() requests the revocation of the certificate
102specified in the I<ctx> using L<OSSL_CMP_CTX_set1_oldCert(3)>.
103RFC 4210 is vague in which PKIStatus should be returned by the server.
104We take "accepted" and "grantedWithMods" as clear success and handle
105"revocationWarning" and "revocationNotification" just as warnings because CAs
106typically return them as an indication that the certificate was already revoked.
107"rejection" is a clear error. The values "waiting" and "keyUpdateWarning"
108make no sense for revocation and thus are treated as an error as well.
109
110OSSL_CMP_exec_GENM_ses() sends a general message containing the sequence of
111infoType and infoValue pairs (InfoTypeAndValue; short: B<ITAV>)
112provided in the I<ctx> using L<OSSL_CMP_CTX_push0_genm_ITAV(3)>.
113It returns the list of B<ITAV>s received in the GenRep.
114This can be used, for instance, to poll for CRLs or CA Key Updates.
115See RFC 4210 section 5.3.19 and appendix E.5 for details.
116
117=head1 NOTES
118
119CMP is defined in RFC 4210 (and CRMF in RFC 4211).
120
121So far the CMP client implementation is limited to one request per CMP message
122(and consequently to at most one response component per CMP message).
123
124=head1 RETURN VALUES
125
126OSSL_CMP_exec_certreq(), OSSL_CMP_exec_IR_ses(), OSSL_CMP_exec_CR_ses(),
127OSSL_CMP_exec_P10CR_ses(), and OSSL_CMP_exec_KUR_ses() return a
128pointer to the newly obtained X509 certificate on success, NULL on error.
129This pointer will be freed implicitly by OSSL_CMP_CTX_free() or
130CSSL_CMP_CTX_reinit().
131
132OSSL_CMP_try_certreq() returns 1 if the requested certificate is available
133via L<OSSL_CMP_CTX_get0_newCert(3)>
134or on successfully aborting a pending certificate request, 0 on error, and -1
135in case a 'waiting' status has been received and checkAfter value is available.
136In the latter case L<OSSL_CMP_CTX_get0_newCert(3)> yields NULL
137and the output parameter I<checkAfter> has been used to
138assign the received value unless I<checkAfter> is NULL.
139
140OSSL_CMP_exec_RR_ses() returns 1 on success, 0 on error.
141
142OSSL_CMP_exec_GENM_ses() returns a
143pointer to the received B<ITAV> sequence on success, NULL on error.
144This pointer must be freed by the caller.
145
146=head1 EXAMPLES
147
148See OSSL_CMP_CTX for examples on how to prepare the context for these
149functions.
150
151=head1 SEE ALSO
152
153L<OSSL_CMP_CTX_new(3)>, L<OSSL_CMP_CTX_free(3)>,
154L<OSSL_CMP_CTX_set1_subjectName(3)>, L<OSSL_CMP_CTX_set0_newPkey(3)>,
155L<OSSL_CMP_CTX_set1_p10CSR(3)>, L<OSSL_CMP_CTX_set1_oldCert(3)>,
156L<OSSL_CMP_CTX_get0_newCert(3)>, L<OSSL_CMP_CTX_push0_genm_ITAV(3)>,
157L<OSSL_CMP_MSG_http_perform(3)>
158
159=head1 HISTORY
160
161The OpenSSL CMP support was added in OpenSSL 3.0.
162
163=head1 COPYRIGHT
164
165Copyright 2007-2021 The OpenSSL Project Authors. All Rights Reserved.
166
167Licensed under the Apache License 2.0 (the "License").  You may not use
168this file except in compliance with the License.  You can obtain a copy
169in the file LICENSE in the source distribution or at
170L<https://www.openssl.org/source/license.html>.
171
172=cut
173