1=pod
2
3=head1 NAME
4
5OSSL_CMP_CTX_new,
6OSSL_CMP_CTX_free,
7OSSL_CMP_CTX_reinit,
8OSSL_CMP_CTX_set_option,
9OSSL_CMP_CTX_get_option,
10OSSL_CMP_CTX_set_log_cb,
11OSSL_CMP_CTX_set_log_verbosity,
12OSSL_CMP_CTX_print_errors,
13OSSL_CMP_CTX_set1_serverPath,
14OSSL_CMP_CTX_set1_server,
15OSSL_CMP_CTX_set_serverPort,
16OSSL_CMP_CTX_set1_proxy,
17OSSL_CMP_CTX_set1_no_proxy,
18OSSL_CMP_CTX_set_http_cb,
19OSSL_CMP_CTX_set_http_cb_arg,
20OSSL_CMP_CTX_get_http_cb_arg,
21OSSL_CMP_transfer_cb_t,
22OSSL_CMP_CTX_set_transfer_cb,
23OSSL_CMP_CTX_set_transfer_cb_arg,
24OSSL_CMP_CTX_get_transfer_cb_arg,
25OSSL_CMP_CTX_set1_srvCert,
26OSSL_CMP_CTX_set1_expected_sender,
27OSSL_CMP_CTX_set0_trustedStore,
28OSSL_CMP_CTX_get0_trustedStore,
29OSSL_CMP_CTX_set1_untrusted,
30OSSL_CMP_CTX_get0_untrusted,
31OSSL_CMP_CTX_set1_cert,
32OSSL_CMP_CTX_build_cert_chain,
33OSSL_CMP_CTX_set1_pkey,
34OSSL_CMP_CTX_set1_referenceValue,
35OSSL_CMP_CTX_set1_secretValue,
36OSSL_CMP_CTX_set1_recipient,
37OSSL_CMP_CTX_push0_geninfo_ITAV,
38OSSL_CMP_CTX_reset_geninfo_ITAVs,
39OSSL_CMP_CTX_set1_extraCertsOut,
40OSSL_CMP_CTX_set0_newPkey,
41OSSL_CMP_CTX_get0_newPkey,
42OSSL_CMP_CTX_set1_issuer,
43OSSL_CMP_CTX_set1_subjectName,
44OSSL_CMP_CTX_push1_subjectAltName,
45OSSL_CMP_CTX_set0_reqExtensions,
46OSSL_CMP_CTX_reqExtensions_have_SAN,
47OSSL_CMP_CTX_push0_policy,
48OSSL_CMP_CTX_set1_oldCert,
49OSSL_CMP_CTX_set1_p10CSR,
50OSSL_CMP_CTX_push0_genm_ITAV,
51OSSL_CMP_certConf_cb_t,
52OSSL_CMP_certConf_cb,
53OSSL_CMP_CTX_set_certConf_cb,
54OSSL_CMP_CTX_set_certConf_cb_arg,
55OSSL_CMP_CTX_get_certConf_cb_arg,
56OSSL_CMP_CTX_get_status,
57OSSL_CMP_CTX_get0_statusString,
58OSSL_CMP_CTX_get_failInfoCode,
59OSSL_CMP_CTX_get0_newCert,
60OSSL_CMP_CTX_get1_newChain,
61OSSL_CMP_CTX_get1_caPubs,
62OSSL_CMP_CTX_get1_extraCertsIn,
63OSSL_CMP_CTX_set1_transactionID,
64OSSL_CMP_CTX_set1_senderNonce
65- functions for managing the CMP client context data structure
66
67=head1 SYNOPSIS
68
69 #include <openssl/cmp.h>
70
71 OSSL_CMP_CTX *OSSL_CMP_CTX_new(OSSL_LIB_CTX *libctx, const char *propq);
72 void OSSL_CMP_CTX_free(OSSL_CMP_CTX *ctx);
73 int OSSL_CMP_CTX_reinit(OSSL_CMP_CTX *ctx);
74 int OSSL_CMP_CTX_set_option(OSSL_CMP_CTX *ctx, int opt, int val);
75 int OSSL_CMP_CTX_get_option(const OSSL_CMP_CTX *ctx, int opt);
76
77 /* logging and error reporting: */
78 int OSSL_CMP_CTX_set_log_cb(OSSL_CMP_CTX *ctx, OSSL_CMP_log_cb_t cb);
79 #define OSSL_CMP_CTX_set_log_verbosity(ctx, level)
80 void OSSL_CMP_CTX_print_errors(const OSSL_CMP_CTX *ctx);
81
82 /* message transfer: */
83 int OSSL_CMP_CTX_set1_serverPath(OSSL_CMP_CTX *ctx, const char *path);
84 int OSSL_CMP_CTX_set1_server(OSSL_CMP_CTX *ctx, const char *address);
85 int OSSL_CMP_CTX_set_serverPort(OSSL_CMP_CTX *ctx, int port);
86 int OSSL_CMP_CTX_set1_proxy(OSSL_CMP_CTX *ctx, const char *name);
87 int OSSL_CMP_CTX_set1_no_proxy(OSSL_CMP_CTX *ctx, const char *names);
88 int OSSL_CMP_CTX_set_http_cb(OSSL_CMP_CTX *ctx, HTTP_bio_cb_t cb);
89 int OSSL_CMP_CTX_set_http_cb_arg(OSSL_CMP_CTX *ctx, void *arg);
90 void *OSSL_CMP_CTX_get_http_cb_arg(const OSSL_CMP_CTX *ctx);
91 typedef OSSL_CMP_MSG *(*OSSL_CMP_transfer_cb_t)(OSSL_CMP_CTX *ctx,
92                                                 const OSSL_CMP_MSG *req);
93 int OSSL_CMP_CTX_set_transfer_cb(OSSL_CMP_CTX *ctx,
94                                  OSSL_CMP_transfer_cb_t cb);
95 int OSSL_CMP_CTX_set_transfer_cb_arg(OSSL_CMP_CTX *ctx, void *arg);
96 void *OSSL_CMP_CTX_get_transfer_cb_arg(const OSSL_CMP_CTX *ctx);
97
98 /* server authentication: */
99 int OSSL_CMP_CTX_set1_srvCert(OSSL_CMP_CTX *ctx, X509 *cert);
100 int OSSL_CMP_CTX_set1_expected_sender(OSSL_CMP_CTX *ctx,
101                                      const X509_NAME *name);
102 int OSSL_CMP_CTX_set0_trustedStore(OSSL_CMP_CTX *ctx, X509_STORE *store);
103 X509_STORE *OSSL_CMP_CTX_get0_trustedStore(const OSSL_CMP_CTX *ctx);
104 int OSSL_CMP_CTX_set1_untrusted(OSSL_CMP_CTX *ctx, STACK_OF(X509) *certs);
105 STACK_OF(X509) *OSSL_CMP_CTX_get0_untrusted(const OSSL_CMP_CTX *ctx);
106
107 /* client authentication: */
108 int OSSL_CMP_CTX_set1_cert(OSSL_CMP_CTX *ctx, X509 *cert);
109 int OSSL_CMP_CTX_build_cert_chain(OSSL_CMP_CTX *ctx, X509_STORE *own_trusted,
110                                   STACK_OF(X509) *candidates);
111 int OSSL_CMP_CTX_set1_pkey(OSSL_CMP_CTX *ctx, EVP_PKEY *pkey);
112 int OSSL_CMP_CTX_set1_referenceValue(OSSL_CMP_CTX *ctx,
113                                      const unsigned char *ref, int len);
114 int OSSL_CMP_CTX_set1_secretValue(OSSL_CMP_CTX *ctx,
115                                   const unsigned char *sec, int len);
116
117 /* CMP message header and extra certificates: */
118 int OSSL_CMP_CTX_set1_recipient(OSSL_CMP_CTX *ctx, const X509_NAME *name);
119 int OSSL_CMP_CTX_push0_geninfo_ITAV(OSSL_CMP_CTX *ctx, OSSL_CMP_ITAV *itav);
120 int OSSL_CMP_CTX_reset_geninfo_ITAVs(OSSL_CMP_CTX *ctx);
121 int OSSL_CMP_CTX_set1_extraCertsOut(OSSL_CMP_CTX *ctx,
122                                     STACK_OF(X509) *extraCertsOut);
123
124 /* certificate template: */
125 int OSSL_CMP_CTX_set0_newPkey(OSSL_CMP_CTX *ctx, int priv, EVP_PKEY *pkey);
126 EVP_PKEY *OSSL_CMP_CTX_get0_newPkey(const OSSL_CMP_CTX *ctx, int priv);
127 int OSSL_CMP_CTX_set1_issuer(OSSL_CMP_CTX *ctx, const X509_NAME *name);
128 int OSSL_CMP_CTX_set1_subjectName(OSSL_CMP_CTX *ctx, const X509_NAME *name);
129 int OSSL_CMP_CTX_push1_subjectAltName(OSSL_CMP_CTX *ctx,
130                                       const GENERAL_NAME *name);
131 int OSSL_CMP_CTX_set0_reqExtensions(OSSL_CMP_CTX *ctx, X509_EXTENSIONS *exts);
132 int OSSL_CMP_CTX_reqExtensions_have_SAN(OSSL_CMP_CTX *ctx);
133 int OSSL_CMP_CTX_push0_policy(OSSL_CMP_CTX *ctx, POLICYINFO *pinfo);
134 int OSSL_CMP_CTX_set1_oldCert(OSSL_CMP_CTX *ctx, X509 *cert);
135 int OSSL_CMP_CTX_set1_p10CSR(OSSL_CMP_CTX *ctx, const X509_REQ *csr);
136
137 /* misc body contents: */
138 int OSSL_CMP_CTX_push0_genm_ITAV(OSSL_CMP_CTX *ctx, OSSL_CMP_ITAV *itav);
139
140 /* certificate confirmation: */
141 typedef int (*OSSL_CMP_certConf_cb_t)(OSSL_CMP_CTX *ctx, X509 *cert,
142                                       int fail_info, const char **txt);
143 int OSSL_CMP_certConf_cb(OSSL_CMP_CTX *ctx, X509 *cert, int fail_info,
144                          const char **text);
145 int OSSL_CMP_CTX_set_certConf_cb(OSSL_CMP_CTX *ctx, OSSL_CMP_certConf_cb_t cb);
146 int OSSL_CMP_CTX_set_certConf_cb_arg(OSSL_CMP_CTX *ctx, void *arg);
147 void *OSSL_CMP_CTX_get_certConf_cb_arg(const OSSL_CMP_CTX *ctx);
148
149 /* result fetching: */
150 int OSSL_CMP_CTX_get_status(const OSSL_CMP_CTX *ctx);
151 OSSL_CMP_PKIFREETEXT *OSSL_CMP_CTX_get0_statusString(const OSSL_CMP_CTX *ctx);
152 int OSSL_CMP_CTX_get_failInfoCode(const OSSL_CMP_CTX *ctx);
153
154 X509 *OSSL_CMP_CTX_get0_newCert(const OSSL_CMP_CTX *ctx);
155 STACK_OF(X509) *OSSL_CMP_CTX_get1_newChain(const OSSL_CMP_CTX *ctx);
156 STACK_OF(X509) *OSSL_CMP_CTX_get1_caPubs(const OSSL_CMP_CTX *ctx);
157 STACK_OF(X509) *OSSL_CMP_CTX_get1_extraCertsIn(const OSSL_CMP_CTX *ctx);
158
159 /* for testing and debugging purposes: */
160 int OSSL_CMP_CTX_set1_transactionID(OSSL_CMP_CTX *ctx,
161                                     const ASN1_OCTET_STRING *id);
162 int OSSL_CMP_CTX_set1_senderNonce(OSSL_CMP_CTX *ctx,
163                                   const ASN1_OCTET_STRING *nonce);
164
165=head1 DESCRIPTION
166
167This is the context API for using CMP (Certificate Management Protocol) with
168OpenSSL.
169
170OSSL_CMP_CTX_new() allocates an B<OSSL_CMP_CTX> structure associated with
171the library context I<libctx> and property query string I<propq>,
172both of which may be NULL to select the defaults.
173It initializes the remaining fields to their default values - for instance,
174the logging verbosity is set to OSSL_CMP_LOG_INFO,
175the message timeout is set to 120 seconds,
176and the proof-of-possession method is set to OSSL_CRMF_POPO_SIGNATURE.
177
178OSSL_CMP_CTX_free() deallocates an OSSL_CMP_CTX structure.
179
180OSSL_CMP_CTX_reinit() prepares the given I<ctx> for a further transaction by
181clearing the internal CMP transaction (aka session) status, PKIStatusInfo,
182and any previous results (newCert, newChain, caPubs, and extraCertsIn)
183from the last executed transaction.
184It also clears any ITAVs that were added by OSSL_CMP_CTX_push0_genm_ITAV().
185All other field values (i.e., CMP options) are retained for potential reuse.
186
187OSSL_CMP_CTX_set_option() sets the given value for the given option
188(e.g., OSSL_CMP_OPT_IMPLICIT_CONFIRM) in the given OSSL_CMP_CTX structure.
189
190The following options can be set:
191
192=over 4
193
194=item B<OSSL_CMP_OPT_LOG_VERBOSITY>
195
196        The level of severity needed for actually outputting log messages
197        due to errors, warnings, general info, debugging, etc.
198        Default is OSSL_CMP_LOG_INFO. See also L<OSSL_CMP_log_open(3)>.
199
200=item B<OSSL_CMP_OPT_KEEP_ALIVE>
201
202        If the given value is 0 then HTTP connections are not kept open
203        after receiving a response, which is the default behavior for HTTP 1.0.
204        If the value is 1 or 2 then persistent connections are requested.
205        If the value is 2 then persistent connections are required,
206        i.e., in case the server does not grant them an error occurs.
207        The default value is 1: prefer to keep the connection open.
208
209=item B<OSSL_CMP_OPT_MSG_TIMEOUT>
210
211        Number of seconds a CMP request-response message round trip
212        is allowed to take before a timeout error is returned.
213        A value <= 0 means no limitation (waiting indefinitely).
214        Default is to use the B<OSSL_CMP_OPT_TOTAL_TIMEOUT> setting.
215
216=item B<OSSL_CMP_OPT_TOTAL_TIMEOUT>
217
218        Maximum total number of seconds a transaction may take,
219        including polling etc.
220        A value <= 0 means no limitation (waiting indefinitely).
221        Default is 0.
222
223=item B<OSSL_CMP_OPT_VALIDITY_DAYS>
224
225        Number of days new certificates are asked to be valid for.
226
227=item B<OSSL_CMP_OPT_SUBJECTALTNAME_NODEFAULT>
228
229        Do not take default Subject Alternative Names
230        from the reference certificate.
231
232=item B<OSSL_CMP_OPT_SUBJECTALTNAME_CRITICAL>
233
234        Demand that the given Subject Alternative Names are flagged as critical.
235
236=item B<OSSL_CMP_OPT_POLICIES_CRITICAL>
237
238        Demand that the given policies are flagged as critical.
239
240=item B<OSSL_CMP_OPT_POPO_METHOD>
241
242        Select the proof of possession method to use. Possible values are:
243
244            OSSL_CRMF_POPO_NONE       - ProofOfPossession field omitted
245            OSSL_CRMF_POPO_RAVERIFIED - assert that the RA has already
246                                        verified the PoPo
247            OSSL_CRMF_POPO_SIGNATURE  - sign a value with private key,
248                                        which is the default.
249            OSSL_CRMF_POPO_KEYENC     - decrypt the encrypted certificate
250                                        ("indirect method")
251
252        Note that a signature-based POPO can only be produced if a private key
253        is provided as the newPkey or client's pkey component of the CMP context.
254
255=item B<OSSL_CMP_OPT_DIGEST_ALGNID>
256
257        The NID of the digest algorithm to be used in RFC 4210's MSG_SIG_ALG
258        for signature-based message protection and Proof-of-Possession (POPO).
259        Default is SHA256.
260
261=item B<OSSL_CMP_OPT_OWF_ALGNID>
262        The NID of the digest algorithm to be used as one-way function (OWF)
263        for MAC-based message protection with password-based MAC (PBM).
264        See RFC 4210 section 5.1.3.1 for details.
265        Default is SHA256.
266
267=item B<OSSL_CMP_OPT_MAC_ALGNID>
268        The NID of the MAC algorithm to be used for message protection with PBM.
269        Default is HMAC-SHA1 as per RFC 4210.
270
271=item B<OSSL_CMP_OPT_REVOCATION_REASON>
272
273        The reason code to be included in a Revocation Request (RR);
274        values: 0..10 (RFC 5210, 5.3.1) or -1 for none, which is the default.
275
276=item B<OSSL_CMP_OPT_IMPLICIT_CONFIRM>
277
278        Request server to enable implicit confirm mode, where the client
279        does not need to send confirmation upon receiving the
280        certificate. If the server does not enable implicit confirmation
281        in the return message, then confirmation is sent anyway.
282
283=item B<OSSL_CMP_OPT_DISABLE_CONFIRM>
284
285        Do not confirm enrolled certificates, to cope with broken servers
286        not supporting implicit confirmation correctly.
287B<WARNING:> This setting leads to unspecified behavior and it is meant
288exclusively to allow interoperability with server implementations violating
289RFC 4210.
290
291=item B<OSSL_CMP_OPT_UNPROTECTED_SEND>
292
293        Send request or response messages without CMP-level protection.
294
295=item B<OSSL_CMP_OPT_UNPROTECTED_ERRORS>
296
297        Accept unprotected error responses which are either explicitly
298        unprotected or where protection verification failed. Applies to regular
299        error messages as well as certificate responses (IP/CP/KUP) and
300        revocation responses (RP) with rejection.
301B<WARNING:> This setting leads to unspecified behavior and it is meant
302exclusively to allow interoperability with server implementations violating
303RFC 4210.
304
305=item B<OSSL_CMP_OPT_IGNORE_KEYUSAGE>
306
307        Ignore key usage restrictions in the signer's certificate when
308        validating signature-based protection in received CMP messages.
309        Else, 'digitalSignature' must be allowed by CMP signer certificates.
310
311=item B<OSSL_CMP_OPT_PERMIT_TA_IN_EXTRACERTS_FOR_IR>
312
313        Allow retrieving a trust anchor from extraCerts and using that
314        to validate the certificate chain of an IP message.
315
316=back
317
318OSSL_CMP_CTX_get_option() reads the current value of the given option
319(e.g., OSSL_CMP_OPT_IMPLICIT_CONFIRM) from the given OSSL_CMP_CTX structure.
320
321OSSL_CMP_CTX_set_log_cb() sets in I<ctx> the callback function I<cb>
322for handling error queue entries and logging messages.
323When I<cb> is NULL errors are printed to STDERR (if available, else ignored)
324any log messages are ignored.
325Alternatively, L<OSSL_CMP_log_open(3)> may be used to direct logging to STDOUT.
326
327OSSL_CMP_CTX_set_log_verbosity() is a macro setting the
328OSSL_CMP_OPT_LOG_VERBOSITY context option to the given level.
329
330OSSL_CMP_CTX_print_errors() outputs any entries in the OpenSSL error queue. It
331is similar to L<ERR_print_errors_cb(3)> but uses the CMP log callback function
332if set in the I<ctx> for uniformity with CMP logging if given. Otherwise it uses
333L<ERR_print_errors(3)> to print to STDERR (unless OPENSSL_NO_STDIO is defined).
334
335OSSL_CMP_CTX_set1_serverPath() sets the HTTP path of the CMP server on the host,
336also known as "CMP alias".
337The default is C</>.
338
339OSSL_CMP_CTX_set1_server() sets the given server I<address>
340(which may be a hostname or IP address or NULL) in the given I<ctx>.
341
342OSSL_CMP_CTX_set_serverPort() sets the port of the CMP server to connect to.
343If not used or the I<port> argument is 0
344the default port applies, which is 80 for HTTP and 443 for HTTPS.
345
346OSSL_CMP_CTX_set1_proxy() sets the HTTP proxy to be used for connecting to
347the given CMP server unless overruled by any "no_proxy" settings (see below).
348If TLS is not used this defaults to the value of
349the environment variable C<http_proxy> if set, else C<HTTP_PROXY>.
350Otherwise defaults to the value of C<https_proxy> if set, else C<HTTPS_PROXY>.
351An empty proxy string specifies not to use a proxy.
352Else the format is C<[http[s]://]address[:port][/path]>,
353where any path given is ignored.
354The default port number is 80, or 443 in case C<https:> is given.
355
356OSSL_CMP_CTX_set1_no_proxy() sets the list of server hostnames not to use
357an HTTP proxy for. The names may be separated by commas and/or whitespace.
358Defaults to the environment variable C<no_proxy> if set, else C<NO_PROXY>.
359
360OSSL_CMP_CTX_set_http_cb() sets the optional BIO connect/disconnect callback
361function, which has the prototype
362
363 typedef BIO *(*HTTP_bio_cb_t) (BIO *bio, void *ctx, int connect, int detail);
364
365The callback may modify the I<bio> provided by L<OSSL_CMP_MSG_http_perform(3)>,
366whereby it may make use of a custom defined argument I<ctx>
367stored in the OSSL_CMP_CTX by means of OSSL_CMP_CTX_set_http_cb_arg().
368During connection establishment, just after calling BIO_do_connect_retry(),
369the function is invoked with the I<connect> argument being 1 and the I<detail>
370argument being 1 if HTTPS is requested, i.e., SSL/TLS should be enabled. On
371disconnect I<connect> is 0 and I<detail> is 1 in case no error occurred, else 0.
372For instance, on connect the function may prepend a TLS BIO to implement HTTPS;
373after disconnect it may do some diagnostic output and/or specific cleanup.
374The function should return NULL to indicate failure.
375After disconnect the modified BIO will be deallocated using BIO_free_all().
376
377OSSL_CMP_CTX_set_http_cb_arg() sets an argument, respectively a pointer to
378a structure containing arguments,
379optionally to be used by the http connect/disconnect callback function.
380I<arg> is not consumed, and it must therefore explicitly be freed when not
381needed any more. I<arg> may be NULL to clear the entry.
382
383OSSL_CMP_CTX_get_http_cb_arg() gets the argument, respectively the pointer to a
384structure containing arguments, previously set by
385OSSL_CMP_CTX_set_http_cb_arg() or NULL if unset.
386
387OSSL_CMP_CTX_set_transfer_cb() sets the message transfer callback function,
388which has the type
389
390 typedef OSSL_CMP_MSG *(*OSSL_CMP_transfer_cb_t) (OSSL_CMP_CTX *ctx,
391                                                  const OSSL_CMP_MSG *req);
392
393Returns 1 on success, 0 on error.
394
395Default is NULL, which implies the use of L<OSSL_CMP_MSG_http_perform(3)>.
396The callback should send the CMP request message it obtains via the I<req>
397parameter and on success return the response, else it must return NULL.
398The transfer callback may make use of a custom defined argument stored in
399the ctx by means of OSSL_CMP_CTX_set_transfer_cb_arg(), which may be retrieved
400again through OSSL_CMP_CTX_get_transfer_cb_arg().
401
402OSSL_CMP_CTX_set_transfer_cb_arg() sets an argument, respectively a pointer to a
403structure containing arguments, optionally to be used by the transfer callback.
404I<arg> is not consumed, and it must therefore explicitly be freed when not
405needed any more. I<arg> may be NULL to clear the entry.
406
407OSSL_CMP_CTX_get_transfer_cb_arg() gets the argument, respectively the pointer
408to a structure containing arguments, previously set by
409OSSL_CMP_CTX_set_transfer_cb_arg() or NULL if unset.
410
411OSSL_CMP_CTX_set1_srvCert() sets the expected server cert in I<ctx> and trusts
412it directly (even if it is expired) when verifying signed response messages.
413This pins the accepted CMP server and
414results in ignoring whatever may be set using OSSL_CMP_CTX_set0_trustedStore().
415Any previously set value is freed.
416The I<cert> argument may be NULL to clear the entry.
417If set, the subject of the certificate is also used
418as default value for the recipient of CMP requests
419and as default value for the expected sender of CMP responses.
420
421OSSL_CMP_CTX_set1_expected_sender() sets the Distinguished Name (DN)
422expected in the sender field of incoming CMP messages.
423Defaults to the subject of the pinned server certificate, if any.
424This can be used to make sure that only a particular entity is accepted as
425CMP message signer, and attackers are not able to use arbitrary certificates
426of a trusted PKI hierarchy to fraudulently pose as CMP server.
427Note that this gives slightly more freedom than OSSL_CMP_CTX_set1_srvCert(),
428which pins the server to the holder of a particular certificate, while the
429expected sender name will continue to match after updates of the server cert.
430
431OSSL_CMP_CTX_set0_trustedStore()
432sets in the CMP context I<ctx> the certificate store of type X509_STORE
433containing trusted certificates, typically of root CAs.
434This is ignored when a certificate is pinned using OSSL_CMP_CTX_set1_srvCert().
435The store may also hold CRLs and a certificate verification callback function
436used for signature-based peer authentication.
437Any store entry already set before is freed.
438When given a NULL parameter the entry is cleared.
439
440OSSL_CMP_CTX_get0_trustedStore()
441extracts from the CMP context I<ctx> the pointer to the currently set
442certificate store containing trust anchors etc., or an empty store if unset.
443
444OSSL_CMP_CTX_set1_untrusted() sets up a list of non-trusted certificates
445of intermediate CAs that may be useful for path construction for the own CMP
446signer certificate, for the own TLS certificate (if any), when verifying peer
447CMP protection certificates, and when verifying newly enrolled certificates.
448The reference counts of those certificates handled successfully are increased.
449
450OSSL_CMP_CTX_get0_untrusted(OSSL_CMP_CTX *ctx) returns a pointer to the
451list of untrusted certs, which may be empty if unset.
452
453OSSL_CMP_CTX_set1_cert() sets the CMP signer certificate, also called protection
454certificate, related to the private key for signature-based message protection.
455Therefore the public key of this I<cert> must correspond to
456the private key set before or thereafter via OSSL_CMP_CTX_set1_pkey().
457When using signature-based protection of CMP request messages
458this CMP signer certificate will be included first in the extraCerts field.
459It serves as fallback reference certificate, see OSSL_CMP_CTX_set1_oldCert().
460The subject of this I<cert> will be used as the sender field of outgoing
461messages, while the subject of any cert set via OSSL_CMP_CTX_set1_oldCert()
462and any value set via OSSL_CMP_CTX_set1_subjectName() are used as fallback.
463
464The I<cert> argument may be NULL to clear the entry.
465
466OSSL_CMP_CTX_build_cert_chain() builds a certificate chain for the CMP signer
467certificate previously set in the I<ctx>. It adds the optional I<candidates>,
468a list of intermediate CA certs that may already constitute the targeted chain,
469to the untrusted certs that may already exist in the I<ctx>.
470Then the function uses this augmented set of certs for chain construction.
471If I<own_trusted> is NULL it builds the chain as far down as possible and
472ignores any verification errors. Else the CMP signer certificate must be
473verifiable where the chain reaches a trust anchor contained in I<own_trusted>.
474On success the function stores the resulting chain in I<ctx>
475for inclusion in the extraCerts field of signature-protected messages.
476Calling this function is optional; by default a chain construction
477is performed on demand that is equivalent to calling this function
478with the I<candidates> and I<own_trusted> arguments being NULL.
479
480OSSL_CMP_CTX_set1_pkey() sets the client's private key corresponding to the
481CMP signer certificate set via OSSL_CMP_CTX_set1_cert().
482This key is used create signature-based protection (protectionAlg = MSG_SIG_ALG)
483of outgoing messages
484unless a symmetric secret has been set via OSSL_CMP_CTX_set1_secretValue().
485The I<pkey> argument may be NULL to clear the entry.
486
487OSSL_CMP_CTX_set1_secretValue() sets in I<ctx> the byte string I<sec> of length
488I<len> to use as pre-shared secret, or clears it if the I<sec> argument is NULL.
489If present, this secret is used to create MAC-based authentication and integrity
490protection (rather than applying signature-based protection)
491of outgoing messages and to verify authenticity and integrity of incoming
492messages that have MAC-based protection (protectionAlg = C<MSG_MAC_ALG>).
493
494OSSL_CMP_CTX_set1_referenceValue() sets the given referenceValue I<ref> with
495length I<len> in the given I<ctx> or clears it if the I<ref> argument is NULL.
496According to RFC 4210 section 5.1.1, if no value for the sender field in
497CMP message headers can be determined (i.e., no CMP signer certificate
498and no subject DN is set via OSSL_CMP_CTX_set1_subjectName()
499then the sender field will contain the NULL-DN
500and the senderKID field of the CMP message header must be set.
501When signature-based protection is used the senderKID will be set to
502the subjectKeyIdentifier of the CMP signer certificate as far as present.
503If not present or when MAC-based protection is used
504the I<ref> value is taken as the fallback value for the senderKID.
505
506OSSL_CMP_CTX_set1_recipient() sets the recipient name that will be used in the
507PKIHeader of CMP request messages, i.e. the X509 name of the (CA) server.
508
509The recipient field in the header of a CMP message is mandatory.
510If not given explicitly the recipient is determined in the following order:
511the subject of the CMP server certificate set using OSSL_CMP_CTX_set1_srvCert(),
512the value set using OSSL_CMP_CTX_set1_issuer(),
513the issuer of the certificate set using OSSL_CMP_CTX_set1_oldCert(),
514the issuer of the CMP signer certificate,
515as far as any of those is present, else the NULL-DN as last resort.
516
517OSSL_CMP_CTX_push0_geninfo_ITAV() adds I<itav> to the stack in the I<ctx> to be
518added to the GeneralInfo field of the CMP PKIMessage header of a request
519message sent with this context.
520
521OSSL_CMP_CTX_reset_geninfo_ITAVs()
522clears any ITAVs that were added by OSSL_CMP_CTX_push0_geninfo_ITAV().
523
524OSSL_CMP_CTX_set1_extraCertsOut() sets the stack of extraCerts that will be
525sent to remote.
526
527OSSL_CMP_CTX_set0_newPkey() can be used to explicitly set the given EVP_PKEY
528structure as the private or public key to be certified in the CMP context.
529The I<priv> parameter must be 0 if and only if the given key is a public key.
530
531OSSL_CMP_CTX_get0_newPkey() gives the key to use for certificate enrollment
532dependent on fields of the CMP context structure:
533the newPkey (which may be a private or public key) if present,
534else the public key in the p10CSR if present, else the client's private key.
535If the I<priv> parameter is not 0 and the selected key does not have a
536private component then NULL is returned.
537
538OSSL_CMP_CTX_set1_issuer() sets the name of the intended issuer that
539will be set in the CertTemplate, i.e., the X509 name of the CA server.
540
541OSSL_CMP_CTX_set1_subjectName() sets the subject DN that will be used in
542the CertTemplate structure when requesting a new cert. For Key Update Requests
543(KUR), it defaults to the subject DN of the reference certificate,
544see OSSL_CMP_CTX_set1_oldCert(). This default is used for Initialization
545Requests (IR) and Certification Requests (CR) only if no SANs are set.
546The I<subjectName> is also used as fallback for the sender field
547of outgoing CMP messages if no reference certificate is available.
548
549OSSL_CMP_CTX_push1_subjectAltName() adds the given X509 name to the list of
550alternate names on the certificate template request. This cannot be used if
551any Subject Alternative Name extension is set via
552OSSL_CMP_CTX_set0_reqExtensions().
553By default, unless B<OSSL_CMP_OPT_SUBJECTALTNAME_NODEFAULT> has been set,
554the Subject Alternative Names are copied from the reference certificate,
555see OSSL_CMP_CTX_set1_oldCert().
556If set and the subject DN is not set with OSSL_CMP_CTX_set1_subjectName() then
557the certificate template of an IR and CR will not be filled with the default
558subject DN from the reference certificate.
559If a subject DN is desired it needs to be set explicitly with
560OSSL_CMP_CTX_set1_subjectName().
561
562OSSL_CMP_CTX_set0_reqExtensions() sets the X.509v3 extensions to be used in
563IR/CR/KUR.
564
565OSSL_CMP_CTX_reqExtensions_have_SAN() returns 1 if the context contains
566a Subject Alternative Name extension, else 0 or -1 on error.
567
568OSSL_CMP_CTX_push0_policy() adds the certificate policy info object
569to the X509_EXTENSIONS of the requested certificate template.
570
571OSSL_CMP_CTX_set1_oldCert() sets the old certificate to be updated in
572Key Update Requests (KUR) or to be revoked in Revocation Requests (RR).
573It must be given for RR, else it defaults to the CMP signer certificate.
574The I<reference certificate> determined in this way, if any, is also used for
575deriving default subject DN, public key, Subject Alternative Names, and the
576default issuer entry in the requested certificate template of IR/CR/KUR.
577The subject of the reference certificate is used as the sender field value
578in CMP message headers.
579Its issuer is used as default recipient in CMP message headers.
580
581OSSL_CMP_CTX_set1_p10CSR() sets the PKCS#10 CSR to use in P10CR messages.
582If such a CSR is provided, its subject, public key, and extension fields are
583also used as fallback values for the certificate template of IR/CR/KUR messages.
584
585OSSL_CMP_CTX_push0_genm_ITAV() adds I<itav> to the stack in the I<ctx> which
586will be the body of a General Message sent with this context.
587
588OSSL_CMP_certConf_cb() is the default certificate confirmation callback function.
589If the callback argument is not NULL it must point to a trust store.
590In this case the function checks that the newly enrolled certificate can be
591verified using this trust store and untrusted certificates from the I<ctx>,
592which have been augmented by the list of extraCerts received.
593During this verification, any certificate status checking is disabled.
594If the callback argument is NULL the function tries building an approximate
595chain as far as possible using the same untrusted certificates from the I<ctx>,
596and if this fails it takes the received extraCerts as fallback.
597The resulting cert chain can be retrieved using OSSL_CMP_CTX_get1_newChain().
598
599OSSL_CMP_CTX_set_certConf_cb() sets the callback used for evaluating the newly
600enrolled certificate before the library sends, depending on its result,
601a positive or negative certConf message to the server. The callback has type
602
603 typedef int (*OSSL_CMP_certConf_cb_t) (OSSL_CMP_CTX *ctx, X509 *cert,
604                                        int fail_info, const char **txt);
605
606and should inspect the certificate it obtains via the I<cert> parameter and may
607overrule the pre-decision given in the I<fail_info> and I<*txt> parameters.
608If it accepts the certificate it must return 0, indicating success. Else it must
609return a bit field reflecting PKIFailureInfo with at least one failure bit and
610may set the I<*txt> output parameter to point to a string constant with more
611detail.  The transfer callback may make use of a custom defined argument stored
612in the I<ctx> by means of OSSL_CMP_CTX_set_certConf_cb_arg(), which may be
613retrieved again through OSSL_CMP_CTX_get_certConf_cb_arg().
614Typically, the callback will check at least that the certificate can be verified
615using a set of trusted certificates.
616It also could compare the subject DN and other fields of the newly
617enrolled certificate with the certificate template of the request.
618
619OSSL_CMP_CTX_set_certConf_cb_arg() sets an argument, respectively a pointer to a
620structure containing arguments, optionally to be used by the certConf callback.
621I<arg> is not consumed, and it must therefore explicitly be freed when not
622needed any more. I<arg> may be NULL to clear the entry.
623
624OSSL_CMP_CTX_get_certConf_cb_arg() gets the argument, respectively the pointer
625to a structure containing arguments, previously set by
626OSSL_CMP_CTX_set_certConf_cb_arg(), or NULL if unset.
627
628OSSL_CMP_CTX_get_status() returns for client contexts the PKIstatus from
629the last received CertRepMessage or Revocation Response or error message:
630=item B<OSSL_CMP_PKISTATUS_accepted> on successful receipt of a GENP message:
631
632=over 4
633
634=item B<OSSL_CMP_PKISTATUS_request>
635
636if an IR/CR/KUR/RR/GENM request message could not be produced,
637
638=item B<OSSL_CMP_PKISTATUS_trans>
639
640on a transmission error or transaction error for this type of request, and
641
642=item B<OSSL_CMP_PKISTATUS_unspecified>
643
644if no such request was attempted or OSSL_CMP_CTX_reinit() has been called.
645
646=back
647
648For server contexts it returns
649B<OSSL_CMP_PKISTATUS_trans> if a transaction is open,
650otherwise B<OSSL_CMP_PKISTATUS_unspecified>.
651
652OSSL_CMP_CTX_get0_statusString() returns the statusString from the last received
653CertRepMessage or Revocation Response or error message, or NULL if unset.
654
655OSSL_CMP_CTX_get_failInfoCode() returns the error code from the failInfo field
656of the last received CertRepMessage or Revocation Response or error message,
657or -1 if no such response was received or OSSL_CMP_CTX_reinit() has been called.
658This is a bit field and the flags for it are specified in the header file
659F<< <openssl/cmp.h> >>.
660The flags start with OSSL_CMP_CTX_FAILINFO, for example:
661OSSL_CMP_CTX_FAILINFO_badAlg. Returns -1 if the failInfoCode field is unset.
662
663OSSL_CMP_CTX_get0_newCert() returns the pointer to the newly obtained
664certificate in case it is available, else NULL.
665
666OSSL_CMP_CTX_get1_newChain() returns a pointer to a duplicate of the stack of
667X.509 certificates computed by OSSL_CMP_certConf_cb() (if this function has
668been called) on the last received certificate response message IP/CP/KUP.
669
670OSSL_CMP_CTX_get1_caPubs() returns a pointer to a duplicate of the list of
671X.509 certificates in the caPubs field of the last received certificate
672response message (of type IP, CP, or KUP),
673or an empty stack if no caPubs have been received in the current transaction.
674
675OSSL_CMP_CTX_get1_extraCertsIn() returns a pointer to a duplicate of the list
676of X.509 certificates contained in the extraCerts field of the last received
677response message (except for pollRep and PKIConf), or
678an empty stack if no extraCerts have been received in the current transaction.
679
680OSSL_CMP_CTX_set1_transactionID() sets the given transaction ID in the given
681OSSL_CMP_CTX structure.
682
683OSSL_CMP_CTX_set1_senderNonce() stores the last sent sender I<nonce> in
684the I<ctx>. This will be used to validate the recipNonce in incoming messages.
685
686=head1 NOTES
687
688CMP is defined in RFC 4210 (and CRMF in RFC 4211).
689
690=head1 RETURN VALUES
691
692OSSL_CMP_CTX_free() and OSSL_CMP_CTX_print_errors() do not return anything.
693
694OSSL_CMP_CTX_new(),
695OSSL_CMP_CTX_get_http_cb_arg(),
696OSSL_CMP_CTX_get_transfer_cb_arg(),
697OSSL_CMP_CTX_get0_trustedStore(),
698OSSL_CMP_CTX_get0_untrusted(),
699OSSL_CMP_CTX_get0_newPkey(),
700OSSL_CMP_CTX_get_certConf_cb_arg(),
701OSSL_CMP_CTX_get0_statusString(),
702OSSL_CMP_CTX_get0_newCert(),
703OSSL_CMP_CTX_get0_newChain(),
704OSSL_CMP_CTX_get1_caPubs(), and
705OSSL_CMP_CTX_get1_extraCertsIn()
706return the intended pointer value as described above or NULL on error.
707
708OSSL_CMP_CTX_get_option(),
709OSSL_CMP_CTX_reqExtensions_have_SAN(),
710OSSL_CMP_CTX_get_status(), and
711OSSL_CMP_CTX_get_failInfoCode()
712return the intended value as described above or -1 on error.
713
714OSSL_CMP_certConf_cb() returns I<fail_info> if it is not equal to 0,
715else 0 on successful validation,
716or else a bit field with the B<OSSL_CMP_PKIFAILUREINFO_incorrectData> bit set.
717
718All other functions, including OSSL_CMP_CTX_reinit()
719and OSSL_CMP_CTX_reset_geninfo_ITAVs(),
720return 1 on success, 0 on error.
721
722=head1 EXAMPLES
723
724The following code omits error handling.
725
726Set up a CMP client context for sending requests and verifying responses:
727
728    cmp_ctx = OSSL_CMP_CTX_new();
729    OSSL_CMP_CTX_set1_server(cmp_ctx, name_or_address);
730    OSSL_CMP_CTX_set1_serverPort(cmp_ctx, port_string);
731    OSSL_CMP_CTX_set1_serverPath(cmp_ctx, path_or_alias);
732    OSSL_CMP_CTX_set0_trustedStore(cmp_ctx, ts);
733
734Set up symmetric credentials for MAC-based message protection such as PBM:
735
736    OSSL_CMP_CTX_set1_referenceValue(cmp_ctx, ref, ref_len);
737    OSSL_CMP_CTX_set1_secretValue(cmp_ctx, sec, sec_len);
738
739Set up the details for certificate requests:
740
741    OSSL_CMP_CTX_set1_subjectName(cmp_ctx, name);
742    OSSL_CMP_CTX_set0_newPkey(cmp_ctx, 1, initialKey);
743
744Perform an Initialization Request transaction:
745
746    initialCert = OSSL_CMP_exec_IR_ses(cmp_ctx);
747
748Reset the transaction state of the CMP context and the credentials:
749
750    OSSL_CMP_CTX_reinit(cmp_ctx);
751    OSSL_CMP_CTX_set1_referenceValue(cmp_ctx, NULL, 0);
752    OSSL_CMP_CTX_set1_secretValue(cmp_ctx, NULL, 0);
753
754Perform a Certification Request transaction, making use of the new credentials:
755
756    OSSL_CMP_CTX_set1_cert(cmp_ctx, initialCert);
757    OSSL_CMP_CTX_set1_pkey(cmp_ctx, initialKey);
758    OSSL_CMP_CTX_set0_newPkey(cmp_ctx, 1, curentKey);
759    currentCert = OSSL_CMP_exec_CR_ses(cmp_ctx);
760
761Perform a Key Update Request, signed using the cert (and key) to be updated:
762
763    OSSL_CMP_CTX_reinit(cmp_ctx);
764    OSSL_CMP_CTX_set1_cert(cmp_ctx, currentCert);
765    OSSL_CMP_CTX_set1_pkey(cmp_ctx, currentKey);
766    OSSL_CMP_CTX_set0_newPkey(cmp_ctx, 1, updatedKey);
767    currentCert = OSSL_CMP_exec_KUR_ses(cmp_ctx);
768    currentKey = updatedKey;
769
770Perform a General Message transaction including, as an example,
771the id-it-signKeyPairTypes OID and prints info on the General Response contents:
772
773    OSSL_CMP_CTX_reinit(cmp_ctx);
774
775    ASN1_OBJECT *type = OBJ_txt2obj("1.3.6.1.5.5.7.4.2", 1);
776    OSSL_CMP_ITAV *itav = OSSL_CMP_ITAV_create(type, NULL);
777    OSSL_CMP_CTX_push0_genm_ITAV(cmp_ctx, itav);
778
779    STACK_OF(OSSL_CMP_ITAV) *itavs;
780    itavs = OSSL_CMP_exec_GENM_ses(cmp_ctx);
781    print_itavs(itavs);
782    sk_OSSL_CMP_ITAV_pop_free(itavs, OSSL_CMP_ITAV_free);
783
784=head1 SEE ALSO
785
786L<OSSL_CMP_exec_IR_ses(3)>, L<OSSL_CMP_exec_CR_ses(3)>,
787L<OSSL_CMP_exec_KUR_ses(3)>, L<OSSL_CMP_exec_GENM_ses(3)>,
788L<OSSL_CMP_exec_certreq(3)>, L<OSSL_CMP_MSG_http_perform(3)>,
789L<ERR_print_errors_cb(3)>
790
791=head1 HISTORY
792
793The OpenSSL CMP support was added in OpenSSL 3.0.
794
795OSSL_CMP_CTX_reset_geninfo_ITAVs() was added in OpenSSL 3.0.8.
796
797=head1 COPYRIGHT
798
799Copyright 2007-2023 The OpenSSL Project Authors. All Rights Reserved.
800
801Licensed under the Apache License 2.0 (the "License").  You may not use
802this file except in compliance with the License.  You can obtain a copy
803in the file LICENSE in the source distribution or at
804L<https://www.openssl.org/source/license.html>.
805
806=cut
807