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_set1_extraCertsOut,
39OSSL_CMP_CTX_set0_newPkey,
40OSSL_CMP_CTX_get0_newPkey,
41OSSL_CMP_CTX_set1_issuer,
42OSSL_CMP_CTX_set1_subjectName,
43OSSL_CMP_CTX_push1_subjectAltName,
44OSSL_CMP_CTX_set0_reqExtensions,
45OSSL_CMP_CTX_reqExtensions_have_SAN,
46OSSL_CMP_CTX_push0_policy,
47OSSL_CMP_CTX_set1_oldCert,
48OSSL_CMP_CTX_set1_p10CSR,
49OSSL_CMP_CTX_push0_genm_ITAV,
50OSSL_CMP_certConf_cb_t,
51OSSL_CMP_certConf_cb,
52OSSL_CMP_CTX_set_certConf_cb,
53OSSL_CMP_CTX_set_certConf_cb_arg,
54OSSL_CMP_CTX_get_certConf_cb_arg,
55OSSL_CMP_CTX_get_status,
56OSSL_CMP_CTX_get0_statusString,
57OSSL_CMP_CTX_get_failInfoCode,
58OSSL_CMP_CTX_get0_newCert,
59OSSL_CMP_CTX_get1_newChain,
60OSSL_CMP_CTX_get1_caPubs,
61OSSL_CMP_CTX_get1_extraCertsIn,
62OSSL_CMP_CTX_set1_transactionID,
63OSSL_CMP_CTX_set1_senderNonce
64- functions for managing the CMP client context data structure
65
66=head1 SYNOPSIS
67
68 #include <openssl/cmp.h>
69
70 OSSL_CMP_CTX *OSSL_CMP_CTX_new(OSSL_LIB_CTX *libctx, const char *propq);
71 void OSSL_CMP_CTX_free(OSSL_CMP_CTX *ctx);
72 int OSSL_CMP_CTX_reinit(OSSL_CMP_CTX *ctx);
73 int OSSL_CMP_CTX_set_option(OSSL_CMP_CTX *ctx, int opt, int val);
74 int OSSL_CMP_CTX_get_option(const OSSL_CMP_CTX *ctx, int opt);
75
76 /* logging and error reporting: */
77 int OSSL_CMP_CTX_set_log_cb(OSSL_CMP_CTX *ctx, OSSL_CMP_log_cb_t cb);
78 #define OSSL_CMP_CTX_set_log_verbosity(ctx, level)
79 void OSSL_CMP_CTX_print_errors(const OSSL_CMP_CTX *ctx);
80
81 /* message transfer: */
82 int OSSL_CMP_CTX_set1_serverPath(OSSL_CMP_CTX *ctx, const char *path);
83 int OSSL_CMP_CTX_set1_server(OSSL_CMP_CTX *ctx, const char *address);
84 int OSSL_CMP_CTX_set_serverPort(OSSL_CMP_CTX *ctx, int port);
85 int OSSL_CMP_CTX_set1_proxy(OSSL_CMP_CTX *ctx, const char *name);
86 int OSSL_CMP_CTX_set1_no_proxy(OSSL_CMP_CTX *ctx, const char *names);
87 int OSSL_CMP_CTX_set_http_cb(OSSL_CMP_CTX *ctx, HTTP_bio_cb_t cb);
88 int OSSL_CMP_CTX_set_http_cb_arg(OSSL_CMP_CTX *ctx, void *arg);
89 void *OSSL_CMP_CTX_get_http_cb_arg(const OSSL_CMP_CTX *ctx);
90 typedef OSSL_CMP_MSG *(*OSSL_CMP_transfer_cb_t)(OSSL_CMP_CTX *ctx,
91                                                 const OSSL_CMP_MSG *req);
92 int OSSL_CMP_CTX_set_transfer_cb(OSSL_CMP_CTX *ctx,
93                                  OSSL_CMP_transfer_cb_t cb);
94 int OSSL_CMP_CTX_set_transfer_cb_arg(OSSL_CMP_CTX *ctx, void *arg);
95 void *OSSL_CMP_CTX_get_transfer_cb_arg(const OSSL_CMP_CTX *ctx);
96
97 /* server authentication: */
98 int OSSL_CMP_CTX_set1_srvCert(OSSL_CMP_CTX *ctx, X509 *cert);
99 int OSSL_CMP_CTX_set1_expected_sender(OSSL_CMP_CTX *ctx,
100                                      const X509_NAME *name);
101 int OSSL_CMP_CTX_set0_trustedStore(OSSL_CMP_CTX *ctx, X509_STORE *store);
102 X509_STORE *OSSL_CMP_CTX_get0_trustedStore(const OSSL_CMP_CTX *ctx);
103 int OSSL_CMP_CTX_set1_untrusted(OSSL_CMP_CTX *ctx, STACK_OF(X509) *certs);
104 STACK_OF(X509) *OSSL_CMP_CTX_get0_untrusted(const OSSL_CMP_CTX *ctx);
105
106 /* client authentication: */
107 int OSSL_CMP_CTX_set1_cert(OSSL_CMP_CTX *ctx, X509 *cert);
108 int OSSL_CMP_CTX_build_cert_chain(OSSL_CMP_CTX *ctx, X509_STORE *own_trusted,
109                                   STACK_OF(X509) *candidates);
110 int OSSL_CMP_CTX_set1_pkey(OSSL_CMP_CTX *ctx, EVP_PKEY *pkey);
111 int OSSL_CMP_CTX_set1_referenceValue(OSSL_CMP_CTX *ctx,
112                                      const unsigned char *ref, int len);
113 int OSSL_CMP_CTX_set1_secretValue(OSSL_CMP_CTX *ctx, const unsigned char *sec,
114                                   const int len);
115
116 /* CMP message header and extra certificates: */
117 int OSSL_CMP_CTX_set1_recipient(OSSL_CMP_CTX *ctx, const X509_NAME *name);
118 int OSSL_CMP_CTX_push0_geninfo_ITAV(OSSL_CMP_CTX *ctx, OSSL_CMP_ITAV *itav);
119 int OSSL_CMP_CTX_set1_extraCertsOut(OSSL_CMP_CTX *ctx,
120                                     STACK_OF(X509) *extraCertsOut);
121
122 /* certificate template: */
123 int OSSL_CMP_CTX_set0_newPkey(OSSL_CMP_CTX *ctx, int priv, EVP_PKEY *pkey);
124 EVP_PKEY *OSSL_CMP_CTX_get0_newPkey(const OSSL_CMP_CTX *ctx, int priv);
125 int OSSL_CMP_CTX_set1_issuer(OSSL_CMP_CTX *ctx, const X509_NAME *name);
126 int OSSL_CMP_CTX_set1_subjectName(OSSL_CMP_CTX *ctx, const X509_NAME *name);
127 int OSSL_CMP_CTX_push1_subjectAltName(OSSL_CMP_CTX *ctx,
128                                       const GENERAL_NAME *name);
129 int OSSL_CMP_CTX_set0_reqExtensions(OSSL_CMP_CTX *ctx, X509_EXTENSIONS *exts);
130 int OSSL_CMP_CTX_reqExtensions_have_SAN(OSSL_CMP_CTX *ctx);
131 int OSSL_CMP_CTX_push0_policy(OSSL_CMP_CTX *ctx, POLICYINFO *pinfo);
132 int OSSL_CMP_CTX_set1_oldCert(OSSL_CMP_CTX *ctx, X509 *cert);
133 int OSSL_CMP_CTX_set1_p10CSR(OSSL_CMP_CTX *ctx, const X509_REQ *csr);
134
135 /* misc body contents: */
136 int OSSL_CMP_CTX_push0_genm_ITAV(OSSL_CMP_CTX *ctx, OSSL_CMP_ITAV *itav);
137
138 /* certificate confirmation: */
139 typedef int (*OSSL_CMP_certConf_cb_t)(OSSL_CMP_CTX *ctx, X509 *cert,
140                                       int fail_info, const char **txt);
141 int OSSL_CMP_certConf_cb(OSSL_CMP_CTX *ctx, X509 *cert, int fail_info,
142                          const char **text);
143 int OSSL_CMP_CTX_set_certConf_cb(OSSL_CMP_CTX *ctx, OSSL_CMP_certConf_cb_t cb);
144 int OSSL_CMP_CTX_set_certConf_cb_arg(OSSL_CMP_CTX *ctx, void *arg);
145 void *OSSL_CMP_CTX_get_certConf_cb_arg(const OSSL_CMP_CTX *ctx);
146
147 /* result fetching: */
148 int OSSL_CMP_CTX_get_status(const OSSL_CMP_CTX *ctx);
149 OSSL_CMP_PKIFREETEXT *OSSL_CMP_CTX_get0_statusString(const OSSL_CMP_CTX *ctx);
150 int OSSL_CMP_CTX_get_failInfoCode(const OSSL_CMP_CTX *ctx);
151
152 X509 *OSSL_CMP_CTX_get0_newCert(const OSSL_CMP_CTX *ctx);
153 STACK_OF(X509) *OSSL_CMP_CTX_get1_newChain(const OSSL_CMP_CTX *ctx);
154 STACK_OF(X509) *OSSL_CMP_CTX_get1_caPubs(const OSSL_CMP_CTX *ctx);
155 STACK_OF(X509) *OSSL_CMP_CTX_get1_extraCertsIn(const OSSL_CMP_CTX *ctx);
156
157 /* for testing and debugging purposes: */
158 int OSSL_CMP_CTX_set1_transactionID(OSSL_CMP_CTX *ctx,
159                                     const ASN1_OCTET_STRING *id);
160 int OSSL_CMP_CTX_set1_senderNonce(OSSL_CMP_CTX *ctx,
161                                   const ASN1_OCTET_STRING *nonce);
162
163=head1 DESCRIPTION
164
165This is the context API for using CMP (Certificate Management Protocol) with
166OpenSSL.
167
168OSSL_CMP_CTX_new() allocates an B<OSSL_CMP_CTX> structure associated with
169the library context I<libctx> and property query string I<propq>,
170both of which may be NULL to select the defaults.
171It initializes the remaining fields to their default values - for instance,
172the logging verbosity is set to OSSL_CMP_LOG_INFO,
173the message timeout is set to 120 seconds,
174and the proof-of-possession method is set to OSSL_CRMF_POPO_SIGNATURE.
175
176OSSL_CMP_CTX_free() deallocates an OSSL_CMP_CTX structure.
177
178OSSL_CMP_CTX_reinit() prepares the given I<ctx> for a further transaction by
179clearing the internal CMP transaction (aka session) status, PKIStatusInfo,
180and any previous results (newCert, newChain, caPubs, and extraCertsIn)
181from the last executed transaction.
182All other field values (i.e., CMP options) are retained for potential re-use.
183
184OSSL_CMP_CTX_set_option() sets the given value for the given option
185(e.g., OSSL_CMP_OPT_IMPLICIT_CONFIRM) in the given OSSL_CMP_CTX structure.
186
187The following options can be set:
188
189=over 4
190
191=item B<OSSL_CMP_OPT_LOG_VERBOSITY>
192
193        The level of severity needed for actually outputting log messages
194        due to errors, warnings, general info, debugging, etc.
195        Default is OSSL_CMP_LOG_INFO. See also L<OSSL_CMP_log_open(3)>.
196
197=item B<OSSL_CMP_OPT_KEEP_ALIVE>
198
199        If the given value is 0 then HTTP connections are not kept open
200        after receiving a response, which is the default behavior for HTTP 1.0.
201        If the value is 1 or 2 then persistent connections are requested.
202        If the value is 2 then persistent connections are required,
203        i.e., in case the server does not grant them an error occurs.
204        The default value is 1: prefer to keep the connection open.
205
206=item B<OSSL_CMP_OPT_MSG_TIMEOUT>
207
208        Number of seconds (or 0 for infinite) a CMP message round trip is
209        allowed to take before a timeout error is returned.
210        Default is to use the B<OSSL_CMP_OPT_MSG_TIMEOUT> setting.
211
212=item B<OSSL_CMP_OPT_TOTAL_TIMEOUT>
213
214        Maximum total number of seconds an enrollment (including polling)
215        may take. Default is 0 (infinite).
216
217=item B<OSSL_CMP_OPT_VALIDITY_DAYS>
218
219        Number of days new certificates are asked to be valid for.
220
221=item B<OSSL_CMP_OPT_SUBJECTALTNAME_NODEFAULT>
222
223        Do not take default Subject Alternative Names
224        from the reference certificate.
225
226=item B<OSSL_CMP_OPT_SUBJECTALTNAME_CRITICAL>
227
228        Demand that the given Subject Alternative Names are flagged as critical.
229
230=item B<OSSL_CMP_OPT_POLICIES_CRITICAL>
231
232        Demand that the given policies are flagged as critical.
233
234=item B<OSSL_CMP_OPT_POPO_METHOD>
235
236        Select the proof of possession method to use. Possible values are:
237
238            OSSL_CRMF_POPO_NONE       - ProofOfPossession field omitted
239            OSSL_CRMF_POPO_RAVERIFIED - assert that the RA has already
240                                        verified the PoPo
241            OSSL_CRMF_POPO_SIGNATURE  - sign a value with private key,
242                                        which is the default.
243            OSSL_CRMF_POPO_KEYENC     - decrypt the encrypted certificate
244                                        ("indirect method")
245
246        Note that a signature-based POPO can only be produced if a private key
247        is provided as the newPkey or client pkey component of the CMP context.
248
249=item B<OSSL_CMP_OPT_DIGEST_ALGNID>
250
251        The NID of the digest algorithm to be used in RFC 4210's MSG_SIG_ALG
252        for signature-based message protection and Proof-of-Possession (POPO).
253        Default is SHA256.
254
255=item B<OSSL_CMP_OPT_OWF_ALGNID>
256        The NID of the digest algorithm to be used as one-way function (OWF)
257        in RFC 4210's MSG_MAC_ALG for PBM-based message protection.
258        Default is SHA256.
259
260=item B<OSSL_CMP_OPT_MAC_ALGNID>
261        The NID of the MAC algorithm to be used in RFC 4210's MSG_MAC_ALG
262        for PBM-based message protection.
263        Default is HMAC-SHA1 as per RFC 4210.
264
265=item B<OSSL_CMP_OPT_REVOCATION_REASON>
266
267        The reason code to be included in a Revocation Request (RR);
268        values: 0..10 (RFC 5210, 5.3.1) or -1 for none, which is the default.
269
270=item B<OSSL_CMP_OPT_IMPLICIT_CONFIRM>
271
272        Request server to enable implicit confirm mode, where the client
273        does not need to send confirmation upon receiving the
274        certificate. If the server does not enable implicit confirmation
275        in the return message, then confirmation is sent anyway.
276
277=item B<OSSL_CMP_OPT_DISABLE_CONFIRM>
278
279        Do not confirm enrolled certificates, to cope with broken servers
280        not supporting implicit confirmation correctly.
281B<WARNING:> This setting leads to unspecified behavior and it is meant
282exclusively to allow interoperability with server implementations violating
283RFC 4210.
284
285=item B<OSSL_CMP_OPT_UNPROTECTED_SEND>
286
287        Send messages without CMP-level protection.
288
289=item B<OSSL_CMP_OPT_UNPROTECTED_ERRORS>
290
291        Accept unprotected error responses which are either explicitly
292        unprotected or where protection verification failed. Applies to regular
293        error messages as well as certificate responses (IP/CP/KUP) and
294        revocation responses (RP) with rejection.
295B<WARNING:> This setting leads to unspecified behavior and it is meant
296exclusively to allow interoperability with server implementations violating
297RFC 4210.
298
299=item B<OSSL_CMP_OPT_IGNORE_KEYUSAGE>
300
301        Ignore key usage restrictions in the signer's certificate when
302        validating signature-based protection in received CMP messages.
303        Else, 'digitalSignature' must be allowed by CMP signer certificates.
304
305=item B<OSSL_CMP_OPT_PERMIT_TA_IN_EXTRACERTS_FOR_IR>
306
307        Allow retrieving a trust anchor from extraCerts and using that
308        to validate the certificate chain of an IP message.
309
310=back
311
312OSSL_CMP_CTX_get_option() reads the current value of the given option
313(e.g., OSSL_CMP_OPT_IMPLICIT_CONFIRM) from the given OSSL_CMP_CTX structure.
314
315OSSL_CMP_CTX_set_log_cb() sets in I<ctx> the callback function I<cb>
316for handling error queue entries and logging messages.
317When I<cb> is NULL errors are printed to STDERR (if available, else ignored)
318any log messages are ignored.
319Alternatively, L<OSSL_CMP_log_open(3)> may be used to direct logging to STDOUT.
320
321OSSL_CMP_CTX_set_log_verbosity() is a macro setting the
322OSSL_CMP_OPT_LOG_VERBOSITY context option to the given level.
323
324OSSL_CMP_CTX_print_errors() outputs any entries in the OpenSSL error queue. It
325is similar to L<ERR_print_errors_cb(3)> but uses the CMP log callback function
326if set in the I<ctx> for uniformity with CMP logging if given. Otherwise it uses
327L<ERR_print_errors(3)> to print to STDERR (unless OPENSSL_NO_STDIO is defined).
328
329OSSL_CMP_CTX_set1_serverPath() sets the HTTP path of the CMP server on the host,
330also known as "CMP alias".
331The default is C</>.
332
333OSSL_CMP_CTX_set1_server() sets the given server I<address>
334(which may be a hostname or IP address or NULL) in the given I<ctx>.
335
336OSSL_CMP_CTX_set_serverPort() sets the port of the CMP server to connect to.
337If not used or the I<port> argument is 0
338the default port applies, which is 80 for HTTP and 443 for HTTPS.
339
340OSSL_CMP_CTX_set1_proxy() sets the HTTP proxy to be used for connecting to
341the given CMP server unless overruled by any "no_proxy" settings (see below).
342If TLS is not used this defaults to the value of
343the environment variable C<http_proxy> if set, else C<HTTP_PROXY>.
344Otherwise defaults to the value of C<https_proxy> if set, else C<HTTPS_PROXY>.
345An empty proxy string specifies not to use a proxy.
346Else the format is C<[http[s]://]address[:port][/path]>,
347where any path given is ignored.
348The default port number is 80, or 443 in case C<https:> is given.
349
350OSSL_CMP_CTX_set1_no_proxy() sets the list of server hostnames not to use
351an HTTP proxy for. The names may be separated by commas and/or whitespace.
352Defaults to the environment variable C<no_proxy> if set, else C<NO_PROXY>.
353
354OSSL_CMP_CTX_set_http_cb() sets the optional BIO connect/disconnect callback
355function, which has the prototype
356
357 typedef BIO *(*HTTP_bio_cb_t) (BIO *bio, void *ctx, int connect, int detail);
358
359The callback may modify the I<bio> provided by L<OSSL_CMP_MSG_http_perform(3)>,
360whereby it may make use of a custom defined argument I<ctx>
361stored in the OSSL_CMP_CTX by means of OSSL_CMP_CTX_set_http_cb_arg().
362During connection establishment, just after calling BIO_do_connect_retry(),
363the function is invoked with the I<connect> argument being 1 and the I<detail>
364argument being 1 if HTTPS is requested, i.e., SSL/TLS should be enabled. On
365disconnect I<connect> is 0 and I<detail> is 1 in case no error occurred, else 0.
366For instance, on connect the function may prepend a TLS BIO to implement HTTPS;
367after disconnect it may do some diagnostic output and/or specific cleanup.
368The function should return NULL to indicate failure.
369After disconnect the modified BIO will be deallocated using BIO_free_all().
370
371OSSL_CMP_CTX_set_http_cb_arg() sets an argument, respectively a pointer to
372a structure containing arguments,
373optionally to be used by the http connect/disconnect callback function.
374I<arg> is not consumed, and it must therefore explicitly be freed when not
375needed any more. I<arg> may be NULL to clear the entry.
376
377OSSL_CMP_CTX_get_http_cb_arg() gets the argument, respectively the pointer to a
378structure containing arguments, previously set by
379OSSL_CMP_CTX_set_http_cb_arg() or NULL if unset.
380
381OSSL_CMP_CTX_set_transfer_cb() sets the message transfer callback function,
382which has the type
383
384 typedef OSSL_CMP_MSG *(*OSSL_CMP_transfer_cb_t) (OSSL_CMP_CTX *ctx,
385                                                  const OSSL_CMP_MSG *req);
386
387Returns 1 on success, 0 on error.
388
389Default is NULL, which implies the use of L<OSSL_CMP_MSG_http_perform(3)>.
390The callback should send the CMP request message it obtains via the I<req>
391parameter and on success return the response, else it must return NULL.
392The transfer callback may make use of a custom defined argument stored in
393the ctx by means of OSSL_CMP_CTX_set_transfer_cb_arg(), which may be retrieved
394again through OSSL_CMP_CTX_get_transfer_cb_arg().
395
396OSSL_CMP_CTX_set_transfer_cb_arg() sets an argument, respectively a pointer to a
397structure containing arguments, optionally to be used by the transfer callback.
398I<arg> is not consumed, and it must therefore explicitly be freed when not
399needed any more. I<arg> may be NULL to clear the entry.
400
401OSSL_CMP_CTX_get_transfer_cb_arg() gets the argument, respectively the pointer
402to a structure containing arguments, previously set by
403OSSL_CMP_CTX_set_transfer_cb_arg() or NULL if unset.
404
405OSSL_CMP_CTX_set1_srvCert() sets the expected server cert in I<ctx> and trusts
406it directly (even if it is expired) when verifying signed response messages.
407May be used alternatively to OSSL_CMP_CTX_set0_trustedStore()
408to pin the accepted server.
409Any previously set value is freed.
410The I<cert> argument may be NULL to clear the entry.
411If set, the subject of the certificate is also used
412as default value for the recipient of CMP requests
413and as default value for the expected sender of CMP responses.
414
415OSSL_CMP_CTX_set1_expected_sender() sets the Distinguished Name (DN)
416expected in the sender field of CMP response messages.
417Defaults to the subject of the pinned server certificate, if any.
418This can be used to make sure that only a particular entity is accepted as
419CMP message signer, and attackers are not able to use arbitrary certificates
420of a trusted PKI hierarchy to fraudulently pose as CMP server.
421Note that this gives slightly more freedom than OSSL_CMP_CTX_set1_srvCert(),
422which pins the server to the holder of a particular certificate, while the
423expected sender name will continue to match after updates of the server cert.
424
425OSSL_CMP_CTX_set0_trustedStore() sets the certificate store of type X509_STORE
426containing trusted (root) CA certificates.
427The store may also hold CRLs and
428a certificate verification callback function used for CMP server authentication.
429Any store entry already set before is freed.
430When given a NULL parameter the entry is cleared.
431
432OSSL_CMP_CTX_get0_trustedStore() returns a pointer to the currently set
433certificate store containing trusted cert etc., or an empty store if unset.
434
435OSSL_CMP_CTX_set1_untrusted() sets up a list of non-trusted certificates
436of intermediate CAs that may be useful for path construction for the CMP client
437certificate, for the TLS client certificate (if any), when verifying
438the CMP server certificate, and when verifying newly enrolled certificates.
439The reference counts of those certificates handled successfully are increased.
440
441OSSL_CMP_CTX_get0_untrusted(OSSL_CMP_CTX *ctx) returns a pointer to the
442list of untrusted certs, which may be empty if unset.
443
444OSSL_CMP_CTX_set1_cert() sets the certificate related to the private key
445used for CMP message protection.
446Therefore the public key of this I<cert> must correspond to
447the private key set before or thereafter via OSSL_CMP_CTX_set1_pkey().
448When using signature-based protection of CMP request messages
449this CMP signer certificate will be included first in the extraCerts field.
450It serves as fallback reference certificate, see OSSL_CMP_CTX_set1_oldCert().
451The subject of this I<cert> will be used as the sender field of outgoing
452messages, while the subject of any cert set via OSSL_CMP_CTX_set1_oldCert()
453and any value set via OSSL_CMP_CTX_set1_subjectName() are used as fallback.
454
455The I<cert> argument may be NULL to clear the entry.
456
457OSSL_CMP_CTX_build_cert_chain() builds a certificate chain for the CMP signer
458certificate previously set in the I<ctx>. It adds the optional I<candidates>,
459a list of intermediate CA certs that may already constitute the targeted chain,
460to the untrusted certs that may already exist in the I<ctx>.
461Then the function uses this augumented set of certs for chain construction.
462If I<own_trusted> is NULL it builds the chain as far down as possible and
463ignores any verification errors. Else the CMP signer certificate must be
464verifiable where the chain reaches a trust anchor contained in I<own_trusted>.
465On success the function stores the resulting chain in I<ctx>
466for inclusion in the extraCerts field of signature-protected messages.
467Calling this function is optional; by default a chain construction
468is performed on demand that is equivalent to calling this function
469with the I<candidates> and I<own_trusted> arguments being NULL.
470
471OSSL_CMP_CTX_set1_pkey() sets the private key corresponding to the
472CMP signer certificate set via OSSL_CMP_CTX_set1_cert().
473This key is used create signature-based protection (protectionAlg = MSG_SIG_ALG)
474of outgoing messages
475unless a PBM secret has been set via OSSL_CMP_CTX_set1_secretValue().
476The I<pkey> argument may be NULL to clear the entry.
477
478OSSL_CMP_CTX_set1_secretValue() sets the byte string I<sec> with length I<len>
479as PBM secret in the given I<ctx> or clears it if the I<sec> argument is NULL.
480If present, this secret is used to create PBM-based protection of outgoing
481messages and to verify any PBM-based protection of incoming messages
482(protectionAlg = MSG_MAC_ALG). PBM stands for Password-Based MAC.
483PBM-based protection takes precedence over signature-based protection.
484
485OSSL_CMP_CTX_set1_referenceValue() sets the given referenceValue I<ref> with
486length I<len> in the given I<ctx> or clears it if the I<ref> argument is NULL.
487According to RFC 4210 section 5.1.1, if no value for the sender field in
488CMP message headers can be determined (i.e., no CMP signer certificate
489and no subject DN is set via OSSL_CMP_CTX_set1_subjectName()
490then the sender field will contain the NULL-DN
491and the senderKID field of the CMP message header must be set.
492When signature-based protection is used the senderKID will be set to
493the subjectKeyIdentifier of the CMP signer certificate as far as present.
494If not present or when PBM-based protection is used
495the I<ref> value is taken as the fallback value for the senderKID.
496
497OSSL_CMP_CTX_set1_recipient() sets the recipient name that will be used in the
498PKIHeader of CMP request messages, i.e. the X509 name of the (CA) server.
499
500The recipient field in the header of a CMP message is mandatory.
501If not given explicitly the recipient is determined in the following order:
502the subject of the CMP server certificate set using OSSL_CMP_CTX_set1_srvCert(),
503the value set using OSSL_CMP_CTX_set1_issuer(),
504the issuer of the certificate set using OSSL_CMP_CTX_set1_oldCert(),
505the issuer of the CMP signer certificate,
506as far as any of those is present, else the NULL-DN as last resort.
507
508OSSL_CMP_CTX_push0_geninfo_ITAV() adds I<itav> to the stack in the I<ctx> to be
509added to the GeneralInfo field of the CMP PKIMessage header of a request
510message sent with this context.
511
512OSSL_CMP_CTX_set1_extraCertsOut() sets the stack of extraCerts that will be
513sent to remote.
514
515OSSL_CMP_CTX_set0_newPkey() can be used to explicitly set the given EVP_PKEY
516structure as the private or public key to be certified in the CMP context.
517The I<priv> parameter must be 0 if and only if the given key is a public key.
518
519OSSL_CMP_CTX_get0_newPkey() gives the key to use for certificate enrollment
520dependent on fields of the CMP context structure:
521the newPkey (which may be a private or public key) if present,
522else the public key in the p10CSR if present, else the client private key.
523If the I<priv> parameter is not 0 and the selected key does not have a
524private component then NULL is returned.
525
526OSSL_CMP_CTX_set1_issuer() sets the name of the intended issuer that
527will be set in the CertTemplate, i.e., the X509 name of the CA server.
528
529OSSL_CMP_CTX_set1_subjectName() sets the subject DN that will be used in
530the CertTemplate structure when requesting a new cert. For Key Update Requests
531(KUR), it defaults to the subject DN of the reference certificate,
532see OSSL_CMP_CTX_set1_oldCert(). This default is used for Initialization
533Requests (IR) and Certification Requests (CR) only if no SANs are set.
534The I<subjectName> is also used as fallback for the sender field
535of outgoing CMP messages if no reference certificate is available.
536
537OSSL_CMP_CTX_push1_subjectAltName() adds the given X509 name to the list of
538alternate names on the certificate template request. This cannot be used if
539any Subject Alternative Name extension is set via
540OSSL_CMP_CTX_set0_reqExtensions().
541By default, unless OSSL_CMP_OPT_SUBJECTALTNAME_NODEFAULT has been set,
542the Subject Alternative Names are copied from the reference certificate,
543see OSSL_CMP_CTX_set1_oldCert().
544If set and the subject DN is not set with OSSL_CMP_CTX_set1_subjectName() then
545the certificate template of an IR and CR will not be filled with the default
546subject DN from the reference certificate.
547If a subject DN is desired it needs to be set explicitly with
548OSSL_CMP_CTX_set1_subjectName().
549
550OSSL_CMP_CTX_set0_reqExtensions() sets the X.509v3 extensions to be used in
551IR/CR/KUR.
552
553OSSL_CMP_CTX_reqExtensions_have_SAN() returns 1 if the context contains
554a Subject Alternative Name extension, else 0 or -1 on error.
555
556OSSL_CMP_CTX_push0_policy() adds the certificate policy info object
557to the X509_EXTENSIONS of the requested certificate template.
558
559OSSL_CMP_CTX_set1_oldCert() sets the old certificate to be updated in
560Key Update Requests (KUR) or to be revoked in Revocation Requests (RR).
561It must be given for RR, else it defaults to the CMP signer certificate.
562The reference certificate determined in this way, if any, is also used for
563deriving default subject DN and Subject Alternative Names and the
564default issuer entry in the requested certificate template of IR/CR/KUR.
565The subject of the reference certificate is used as the sender field value
566in CMP message headers.
567Its issuer is used as default recipient in CMP message headers.
568
569OSSL_CMP_CTX_set1_p10CSR() sets the PKCS#10 CSR to be used in P10CR.
570
571OSSL_CMP_CTX_push0_genm_ITAV() adds I<itav> to the stack in the I<ctx> which
572will be the body of a General Message sent with this context.
573
574OSSL_CMP_certConf_cb() is the default certificate confirmation callback function.
575If the callback argument is not NULL it must point to a trust store.
576In this case the function checks that the newly enrolled certificate can be
577verified using this trust store and untrusted certificates from the I<ctx>,
578which have been augmented by the list of extraCerts received.
579If the callback argument is NULL the function tries building an approximate
580chain as far as possible using the same untrusted certificates from the I<ctx>,
581and if this fails it takes the received extraCerts as fallback.
582The resulting cert chain can be retrieved using OSSL_CMP_CTX_get1_newChain().
583
584OSSL_CMP_CTX_set_certConf_cb() sets the callback used for evaluating the newly
585enrolled certificate before the library sends, depending on its result,
586a positive or negative certConf message to the server. The callback has type
587
588 typedef int (*OSSL_CMP_certConf_cb_t) (OSSL_CMP_CTX *ctx, X509 *cert,
589                                        int fail_info, const char **txt);
590
591and should inspect the certificate it obtains via the I<cert> parameter and may
592overrule the pre-decision given in the I<fail_info> and I<*txt> parameters.
593If it accepts the certificate it must return 0, indicating success. Else it must
594return a bit field reflecting PKIFailureInfo with at least one failure bit and
595may set the I<*txt> output parameter to point to a string constant with more
596detail.  The transfer callback may make use of a custom defined argument stored
597in the I<ctx> by means of OSSL_CMP_CTX_set_certConf_cb_arg(), which may be
598retrieved again through OSSL_CMP_CTX_get_certConf_cb_arg().
599Typically, the callback will check at least that the certificate can be verified
600using a set of trusted certificates.
601It also could compare the subject DN and other fields of the newly
602enrolled certificate with the certificate template of the request.
603
604OSSL_CMP_CTX_set_certConf_cb_arg() sets an argument, respectively a pointer to a
605structure containing arguments, optionally to be used by the certConf callback.
606I<arg> is not consumed, and it must therefore explicitly be freed when not
607needed any more. I<arg> may be NULL to clear the entry.
608
609OSSL_CMP_CTX_get_certConf_cb_arg() gets the argument, respectively the pointer
610to a structure containing arguments, previously set by
611OSSL_CMP_CTX_set_certConf_cb_arg(), or NULL if unset.
612
613OSSL_CMP_CTX_get_status() returns the PKIstatus from the last received
614CertRepMessage or Revocation Response or error message, or -1 if unset.
615For server contexts it returns -2 if a transaction is open, else -1.
616
617OSSL_CMP_CTX_get0_statusString() returns the statusString from the last received
618CertRepMessage or Revocation Response or error message, or NULL if unset.
619
620OSSL_CMP_CTX_get_failInfoCode() returns the error code from the failInfo field
621of the last received CertRepMessage or Revocation Response or error message.
622This is a bit field and the flags for it are specified in the header file
623F<< <openssl/cmp.h> >>.
624The flags start with OSSL_CMP_CTX_FAILINFO, for example:
625OSSL_CMP_CTX_FAILINFO_badAlg. Returns -1 if the failInfoCode field is unset.
626
627OSSL_CMP_CTX_get0_newCert() returns the pointer to the newly obtained
628certificate in case it is available, else NULL.
629
630OSSL_CMP_CTX_get1_newChain() returns a pointer to a duplicate of the stack of
631X.509 certificates computed by OSSL_CMP_certConf_cb() (if this function has
632been called) on the last received certificate response message IP/CP/KUP.
633
634OSSL_CMP_CTX_get1_caPubs() returns a pointer to a duplicate of the list of
635X.509 certificates in the caPubs field of the last received certificate
636response message (of type IP, CP, or KUP),
637or an empty stack if no caPubs have been received in the current transaction.
638
639OSSL_CMP_CTX_get1_extraCertsIn() returns a pointer to a duplicate of the list
640of X.509 certificates contained in the extraCerts field of the last received
641response message (except for pollRep and PKIConf), or
642an empty stack if no extraCerts have been received in the current transaction.
643
644OSSL_CMP_CTX_set1_transactionID() sets the given transaction ID in the given
645OSSL_CMP_CTX structure.
646
647OSSL_CMP_CTX_set1_senderNonce() stores the last sent sender I<nonce> in
648the I<ctx>. This will be used to validate the recipNonce in incoming messages.
649
650=head1 NOTES
651
652CMP is defined in RFC 4210 (and CRMF in RFC 4211).
653
654=head1 RETURN VALUES
655
656OSSL_CMP_CTX_free() and OSSL_CMP_CTX_print_errors() do not return anything.
657
658OSSL_CMP_CTX_new(),
659OSSL_CMP_CTX_get_http_cb_arg(),
660OSSL_CMP_CTX_get_transfer_cb_arg(),
661OSSL_CMP_CTX_get0_trustedStore(),
662OSSL_CMP_CTX_get0_untrusted(),
663OSSL_CMP_CTX_get0_newPkey(),
664OSSL_CMP_CTX_get_certConf_cb_arg(),
665OSSL_CMP_CTX_get0_statusString(),
666OSSL_CMP_CTX_get0_newCert(),
667OSSL_CMP_CTX_get0_newChain(),
668OSSL_CMP_CTX_get1_caPubs(), and
669OSSL_CMP_CTX_get1_extraCertsIn()
670return the intended pointer value as described above or NULL on error.
671
672OSSL_CMP_CTX_get_option(),
673OSSL_CMP_CTX_reqExtensions_have_SAN(),
674OSSL_CMP_CTX_get_status(), and
675OSSL_CMP_CTX_get_failInfoCode()
676return the intended value as described above or -1 on error.
677
678OSSL_CMP_certConf_cb() returns I<fail_info> if it is not equal to 0,
679else 0 on successful validation,
680or else a bit field with the B<OSSL_CMP_PKIFAILUREINFO_incorrectData> bit set.
681
682All other functions return 1 on success, 0 on error.
683
684=head1 EXAMPLES
685
686The following code omits error handling.
687
688Set up a CMP client context for sending requests and verifying responses:
689
690    cmp_ctx = OSSL_CMP_CTX_new();
691    OSSL_CMP_CTX_set1_server(cmp_ctx, name_or_address);
692    OSSL_CMP_CTX_set1_serverPort(cmp_ctx, port_string);
693    OSSL_CMP_CTX_set1_serverPath(cmp_ctx, path_or_alias);
694    OSSL_CMP_CTX_set0_trustedStore(cmp_ctx, ts);
695
696Set up client credentials for password-based protection (PBM):
697
698    OSSL_CMP_CTX_set1_referenceValue(cmp_ctx, ref, ref_len);
699    OSSL_CMP_CTX_set1_secretValue(cmp_ctx, sec, sec_len);
700
701Set up the details for certificate requests:
702
703    OSSL_CMP_CTX_set1_subjectName(cmp_ctx, name);
704    OSSL_CMP_CTX_set0_newPkey(cmp_ctx, 1, initialKey);
705
706Perform an Initialization Request transaction:
707
708    initialCert = OSSL_CMP_exec_IR_ses(cmp_ctx);
709
710Reset the transaction state of the CMP context and the credentials:
711
712    OSSL_CMP_CTX_reinit(cmp_ctx);
713    OSSL_CMP_CTX_set1_referenceValue(cmp_ctx, NULL, 0);
714    OSSL_CMP_CTX_set1_secretValue(cmp_ctx, NULL, 0);
715
716Perform a Certification Request transaction, making use of the new credentials:
717
718    OSSL_CMP_CTX_set1_cert(cmp_ctx, initialCert);
719    OSSL_CMP_CTX_set1_pkey(cmp_ctx, initialKey);
720    OSSL_CMP_CTX_set0_newPkey(cmp_ctx, 1, curentKey);
721    currentCert = OSSL_CMP_exec_CR_ses(cmp_ctx);
722
723Perform a Key Update Request, signed using the cert (and key) to be updated:
724
725    OSSL_CMP_CTX_reinit(cmp_ctx);
726    OSSL_CMP_CTX_set1_cert(cmp_ctx, currentCert);
727    OSSL_CMP_CTX_set1_pkey(cmp_ctx, currentKey);
728    OSSL_CMP_CTX_set0_newPkey(cmp_ctx, 1, updatedKey);
729    currentCert = OSSL_CMP_exec_KUR_ses(cmp_ctx);
730    currentKey = updatedKey;
731
732Perform a General Message transaction including, as an example,
733the id-it-signKeyPairTypes OID and prints info on the General Response contents:
734
735    OSSL_CMP_CTX_reinit(cmp_ctx);
736
737    ASN1_OBJECT *type = OBJ_txt2obj("1.3.6.1.5.5.7.4.2", 1);
738    OSSL_CMP_ITAV *itav = OSSL_CMP_ITAV_new(type, NULL);
739    OSSL_CMP_CTX_push0_genm_ITAV(cmp_ctx, itav);
740
741    STACK_OF(OSSL_CMP_ITAV) *itavs;
742    itavs = OSSL_CMP_exec_GENM_ses(cmp_ctx);
743    print_itavs(itavs);
744    sk_OSSL_CMP_ITAV_pop_free(itavs, OSSL_CMP_ITAV_free);
745
746=head1 SEE ALSO
747
748L<OSSL_CMP_exec_IR_ses(3)>, L<OSSL_CMP_exec_CR_ses(3)>,
749L<OSSL_CMP_exec_KUR_ses(3)>, L<OSSL_CMP_exec_GENM_ses(3)>,
750L<OSSL_CMP_exec_certreq(3)>, L<OSSL_CMP_MSG_http_perform(3)>,
751L<ERR_print_errors_cb(3)>
752
753=head1 HISTORY
754
755The OpenSSL CMP support was added in OpenSSL 3.0.
756
757=head1 COPYRIGHT
758
759Copyright 2007-2021 The OpenSSL Project Authors. All Rights Reserved.
760
761Licensed under the Apache License 2.0 (the "License").  You may not use
762this file except in compliance with the License.  You can obtain a copy
763in the file LICENSE in the source distribution or at
764L<https://www.openssl.org/source/license.html>.
765
766=cut
767