xref: /freebsd/crypto/openssl/crypto/cmp/cmp_server.c (revision f25b8c9fb4f58cf61adb47d7570abe7caa6d385d)
1 /*
2  * Copyright 2007-2025 The OpenSSL Project Authors. All Rights Reserved.
3  * Copyright Nokia 2007-2019
4  * Copyright Siemens AG 2015-2019
5  *
6  * Licensed under the Apache License 2.0 (the "License").  You may not use
7  * this file except in compliance with the License.  You can obtain a copy
8  * in the file LICENSE in the source distribution or at
9  * https://www.openssl.org/source/license.html
10  */
11 
12 /* general CMP server functions */
13 
14 #include <openssl/asn1t.h>
15 
16 #include "cmp_local.h"
17 
18 /* explicit #includes not strictly needed since implied by the above: */
19 #include <openssl/cmp.h>
20 #include <openssl/err.h>
21 
22 /* the context for the generic CMP server */
23 struct ossl_cmp_srv_ctx_st {
24     OSSL_CMP_CTX *ctx; /* CMP client context reused for transactionID etc. */
25     void *custom_ctx; /* application-specific server context */
26     int certReqId; /* of ir/cr/kur, OSSL_CMP_CERTREQID_NONE for p10cr */
27     int polling; /* current transaction is in polling mode */
28 
29     OSSL_CMP_SRV_cert_request_cb_t process_cert_request;
30     OSSL_CMP_SRV_rr_cb_t process_rr;
31     OSSL_CMP_SRV_genm_cb_t process_genm;
32     OSSL_CMP_SRV_error_cb_t process_error;
33     OSSL_CMP_SRV_certConf_cb_t process_certConf;
34     OSSL_CMP_SRV_pollReq_cb_t process_pollReq;
35     OSSL_CMP_SRV_delayed_delivery_cb_t delayed_delivery;
36     OSSL_CMP_SRV_clean_transaction_cb_t clean_transaction;
37 
38     int sendUnprotectedErrors; /* Send error and rejection msgs unprotected */
39     int acceptUnprotected; /* Accept requests with no/invalid prot. */
40     int acceptRAVerified; /* Accept ir/cr/kur with POPO RAVerified */
41     int grantImplicitConfirm; /* Grant implicit confirmation if requested */
42 
43 }; /* OSSL_CMP_SRV_CTX */
44 
45 void OSSL_CMP_SRV_CTX_free(OSSL_CMP_SRV_CTX *srv_ctx)
46 {
47     if (srv_ctx == NULL)
48         return;
49 
50     OSSL_CMP_CTX_free(srv_ctx->ctx);
51     OPENSSL_free(srv_ctx);
52 }
53 
54 OSSL_CMP_SRV_CTX *OSSL_CMP_SRV_CTX_new(OSSL_LIB_CTX *libctx, const char *propq)
55 {
56     OSSL_CMP_SRV_CTX *ctx = OPENSSL_zalloc(sizeof(OSSL_CMP_SRV_CTX));
57 
58     if (ctx == NULL)
59         goto err;
60 
61     if ((ctx->ctx = OSSL_CMP_CTX_new(libctx, propq)) == NULL)
62         goto err;
63     ctx->certReqId = OSSL_CMP_CERTREQID_INVALID;
64     ctx->polling = 0;
65 
66     /* all other elements are initialized to 0 or NULL, respectively */
67     return ctx;
68 err:
69     OSSL_CMP_SRV_CTX_free(ctx);
70     return NULL;
71 }
72 
73 int OSSL_CMP_SRV_CTX_init(OSSL_CMP_SRV_CTX *srv_ctx, void *custom_ctx,
74     OSSL_CMP_SRV_cert_request_cb_t process_cert_request,
75     OSSL_CMP_SRV_rr_cb_t process_rr,
76     OSSL_CMP_SRV_genm_cb_t process_genm,
77     OSSL_CMP_SRV_error_cb_t process_error,
78     OSSL_CMP_SRV_certConf_cb_t process_certConf,
79     OSSL_CMP_SRV_pollReq_cb_t process_pollReq)
80 {
81     if (srv_ctx == NULL) {
82         ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
83         return 0;
84     }
85     srv_ctx->custom_ctx = custom_ctx;
86     srv_ctx->process_cert_request = process_cert_request;
87     srv_ctx->process_rr = process_rr;
88     srv_ctx->process_genm = process_genm;
89     srv_ctx->process_error = process_error;
90     srv_ctx->process_certConf = process_certConf;
91     srv_ctx->process_pollReq = process_pollReq;
92     return 1;
93 }
94 
95 int OSSL_CMP_SRV_CTX_init_trans(OSSL_CMP_SRV_CTX *srv_ctx,
96     OSSL_CMP_SRV_delayed_delivery_cb_t delay,
97     OSSL_CMP_SRV_clean_transaction_cb_t clean)
98 {
99     if (srv_ctx == NULL) {
100         ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
101         return 0;
102     }
103     srv_ctx->delayed_delivery = delay;
104     srv_ctx->clean_transaction = clean;
105     return 1;
106 }
107 
108 OSSL_CMP_CTX *OSSL_CMP_SRV_CTX_get0_cmp_ctx(const OSSL_CMP_SRV_CTX *srv_ctx)
109 {
110     if (srv_ctx == NULL) {
111         ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
112         return NULL;
113     }
114     return srv_ctx->ctx;
115 }
116 
117 void *OSSL_CMP_SRV_CTX_get0_custom_ctx(const OSSL_CMP_SRV_CTX *srv_ctx)
118 {
119     if (srv_ctx == NULL) {
120         ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
121         return NULL;
122     }
123     return srv_ctx->custom_ctx;
124 }
125 
126 int OSSL_CMP_SRV_CTX_set_send_unprotected_errors(OSSL_CMP_SRV_CTX *srv_ctx,
127     int val)
128 {
129     if (srv_ctx == NULL) {
130         ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
131         return 0;
132     }
133     srv_ctx->sendUnprotectedErrors = val != 0;
134     return 1;
135 }
136 
137 int OSSL_CMP_SRV_CTX_set_accept_unprotected(OSSL_CMP_SRV_CTX *srv_ctx, int val)
138 {
139     if (srv_ctx == NULL) {
140         ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
141         return 0;
142     }
143     srv_ctx->acceptUnprotected = val != 0;
144     return 1;
145 }
146 
147 int OSSL_CMP_SRV_CTX_set_accept_raverified(OSSL_CMP_SRV_CTX *srv_ctx, int val)
148 {
149     if (srv_ctx == NULL) {
150         ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
151         return 0;
152     }
153     srv_ctx->acceptRAVerified = val != 0;
154     return 1;
155 }
156 
157 int OSSL_CMP_SRV_CTX_set_grant_implicit_confirm(OSSL_CMP_SRV_CTX *srv_ctx,
158     int val)
159 {
160     if (srv_ctx == NULL) {
161         ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
162         return 0;
163     }
164     srv_ctx->grantImplicitConfirm = val != 0;
165     return 1;
166 }
167 
168 /* return error msg with waiting status if polling is initiated, else NULL */
169 static OSSL_CMP_MSG *delayed_delivery(OSSL_CMP_SRV_CTX *srv_ctx,
170     const OSSL_CMP_MSG *req)
171 {
172     int ret;
173     unsigned long err;
174     int status = OSSL_CMP_PKISTATUS_waiting,
175         fail_info = 0, errorCode = 0;
176     const char *txt = NULL, *details = NULL;
177     OSSL_CMP_PKISI *si;
178     OSSL_CMP_MSG *msg;
179 
180     if (!ossl_assert(srv_ctx != NULL && srv_ctx->ctx != NULL && req != NULL
181             && srv_ctx->delayed_delivery != NULL))
182         return NULL;
183 
184     ret = srv_ctx->delayed_delivery(srv_ctx, req);
185     if (ret == 0)
186         return NULL;
187     if (ret == 1) {
188         srv_ctx->polling = 1;
189     } else {
190         status = OSSL_CMP_PKISTATUS_rejection;
191         fail_info = 1 << OSSL_CMP_PKIFAILUREINFO_systemFailure;
192         txt = "server application error";
193         err = ERR_peek_error();
194         errorCode = ERR_GET_REASON(err);
195         details = ERR_reason_error_string(err);
196     }
197 
198     si = OSSL_CMP_STATUSINFO_new(status, fail_info, txt);
199     if (si == NULL)
200         return NULL;
201 
202     msg = ossl_cmp_error_new(srv_ctx->ctx, si, errorCode, details,
203         srv_ctx->sendUnprotectedErrors);
204     OSSL_CMP_PKISI_free(si);
205     return msg;
206 }
207 
208 /*
209  * Processes an ir/cr/p10cr/kur and returns a certification response.
210  * Only handles the first certification request contained in req
211  * returns an ip/cp/kup on success and NULL on error
212  */
213 static OSSL_CMP_MSG *process_cert_request(OSSL_CMP_SRV_CTX *srv_ctx,
214     const OSSL_CMP_MSG *req)
215 {
216     OSSL_CMP_MSG *msg = NULL;
217     OSSL_CMP_PKISI *si = NULL;
218     X509 *certOut = NULL;
219     EVP_PKEY *keyOut = NULL;
220     STACK_OF(X509) *chainOut = NULL, *caPubs = NULL;
221     const OSSL_CRMF_MSG *crm = NULL;
222     const X509_REQ *p10cr = NULL;
223     int bodytype;
224     int certReqId, central_keygen;
225 
226     if (!ossl_assert(srv_ctx != NULL && srv_ctx->ctx != NULL && req != NULL))
227         return NULL;
228 
229     switch (OSSL_CMP_MSG_get_bodytype(req)) {
230     case OSSL_CMP_PKIBODY_P10CR:
231     case OSSL_CMP_PKIBODY_CR:
232         bodytype = OSSL_CMP_PKIBODY_CP;
233         break;
234     case OSSL_CMP_PKIBODY_IR:
235         bodytype = OSSL_CMP_PKIBODY_IP;
236         break;
237     case OSSL_CMP_PKIBODY_KUR:
238         bodytype = OSSL_CMP_PKIBODY_KUP;
239         break;
240     default:
241         ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
242         return NULL;
243     }
244 
245     if (OSSL_CMP_MSG_get_bodytype(req) == OSSL_CMP_PKIBODY_P10CR) {
246         certReqId = OSSL_CMP_CERTREQID_NONE; /* p10cr does not include an Id */
247         p10cr = req->body->value.p10cr;
248     } else {
249         OSSL_CRMF_MSGS *reqs = req->body->value.ir; /* same for cr and kur */
250 
251         if (sk_OSSL_CRMF_MSG_num(reqs) != 1) {
252             ERR_raise(ERR_LIB_CMP, CMP_R_MULTIPLE_REQUESTS_NOT_SUPPORTED);
253             return NULL;
254         }
255         if ((crm = sk_OSSL_CRMF_MSG_value(reqs, 0)) == NULL) {
256             ERR_raise(ERR_LIB_CMP, CMP_R_CERTREQMSG_NOT_FOUND);
257             return NULL;
258         }
259         certReqId = OSSL_CRMF_MSG_get_certReqId(crm);
260         if (certReqId != OSSL_CMP_CERTREQID) { /* so far, only possible value */
261             ERR_raise(ERR_LIB_CMP, CMP_R_BAD_REQUEST_ID);
262             return NULL;
263         }
264     }
265     srv_ctx->certReqId = certReqId;
266 
267     central_keygen = OSSL_CRMF_MSG_centralkeygen_requested(crm, p10cr);
268     if (central_keygen < 0)
269         return NULL;
270     if (central_keygen == 0
271         && !ossl_cmp_verify_popo(srv_ctx->ctx, req, srv_ctx->acceptRAVerified)) {
272         /* Proof of possession could not be verified */
273         si = OSSL_CMP_STATUSINFO_new(OSSL_CMP_PKISTATUS_rejection,
274             1 << OSSL_CMP_PKIFAILUREINFO_badPOP,
275             ERR_reason_error_string(ERR_peek_error()));
276         if (si == NULL)
277             return NULL;
278     } else {
279         OSSL_CMP_PKIHEADER *hdr = OSSL_CMP_MSG_get0_header(req);
280 
281         si = srv_ctx->process_cert_request(srv_ctx, req, certReqId, crm, p10cr,
282             &certOut, &chainOut, &caPubs);
283         if (si == NULL)
284             goto err;
285         if (ossl_cmp_pkisi_get_status(si) == OSSL_CMP_PKISTATUS_waiting)
286             srv_ctx->polling = 1;
287         /* set OSSL_CMP_OPT_IMPLICIT_CONFIRM if and only if transaction ends */
288         if (!OSSL_CMP_CTX_set_option(srv_ctx->ctx,
289                 OSSL_CMP_OPT_IMPLICIT_CONFIRM,
290                 ossl_cmp_hdr_has_implicitConfirm(hdr)
291                     && srv_ctx->grantImplicitConfirm
292                     /* do not set if polling starts: */
293                     && certOut != NULL))
294             goto err;
295         if (central_keygen == 1
296             && srv_ctx->ctx->newPkey_priv && srv_ctx->ctx->newPkey != NULL)
297             keyOut = srv_ctx->ctx->newPkey;
298     }
299 
300     msg = ossl_cmp_certrep_new(srv_ctx->ctx, bodytype, certReqId, si,
301         certOut, keyOut, NULL /* enc */, chainOut, caPubs,
302         srv_ctx->sendUnprotectedErrors);
303     /* When supporting OSSL_CRMF_POPO_KEYENC, "enc" will need to be set */
304     if (msg == NULL)
305         ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_CREATING_CERTREP);
306 
307 err:
308     OSSL_CMP_PKISI_free(si);
309     X509_free(certOut);
310     OSSL_CMP_CTX_set0_newPkey(srv_ctx->ctx, 0, NULL);
311     OSSL_STACK_OF_X509_free(chainOut);
312     OSSL_STACK_OF_X509_free(caPubs);
313     return msg;
314 }
315 
316 static OSSL_CMP_MSG *process_rr(OSSL_CMP_SRV_CTX *srv_ctx,
317     const OSSL_CMP_MSG *req)
318 {
319     OSSL_CMP_MSG *msg = NULL;
320     OSSL_CMP_REVDETAILS *details;
321     OSSL_CRMF_CERTID *certId = NULL;
322     OSSL_CRMF_CERTTEMPLATE *tmpl;
323     const X509_NAME *issuer;
324     const ASN1_INTEGER *serial;
325     OSSL_CMP_PKISI *si;
326 
327     if (!ossl_assert(srv_ctx != NULL && srv_ctx->ctx != NULL && req != NULL))
328         return NULL;
329 
330     if (sk_OSSL_CMP_REVDETAILS_num(req->body->value.rr) != 1) {
331         ERR_raise(ERR_LIB_CMP, CMP_R_MULTIPLE_REQUESTS_NOT_SUPPORTED);
332         return NULL;
333     }
334     details = sk_OSSL_CMP_REVDETAILS_value(req->body->value.rr, 0);
335     if (details == NULL) {
336         ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_PROCESSING_MESSAGE);
337         return NULL;
338     }
339 
340     tmpl = details->certDetails;
341     issuer = OSSL_CRMF_CERTTEMPLATE_get0_issuer(tmpl);
342     serial = OSSL_CRMF_CERTTEMPLATE_get0_serialNumber(tmpl);
343     if (issuer != NULL && serial != NULL
344         && (certId = OSSL_CRMF_CERTID_gen(issuer, serial)) == NULL)
345         return NULL;
346     if ((si = srv_ctx->process_rr(srv_ctx, req, issuer, serial)) == NULL)
347         goto err;
348 
349     if ((msg = ossl_cmp_rp_new(srv_ctx->ctx, si, certId,
350              srv_ctx->sendUnprotectedErrors))
351         == NULL)
352         ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_CREATING_RR);
353 
354 err:
355     OSSL_CRMF_CERTID_free(certId);
356     OSSL_CMP_PKISI_free(si);
357     return msg;
358 }
359 
360 /*
361  * Processes genm and creates a genp message mirroring the contents of the
362  * incoming message
363  */
364 static OSSL_CMP_MSG *process_genm(OSSL_CMP_SRV_CTX *srv_ctx,
365     const OSSL_CMP_MSG *req)
366 {
367     OSSL_CMP_GENMSGCONTENT *itavs;
368     OSSL_CMP_MSG *msg;
369 
370     if (!ossl_assert(srv_ctx != NULL && srv_ctx->ctx != NULL && req != NULL))
371         return NULL;
372 
373     if (!srv_ctx->process_genm(srv_ctx, req, req->body->value.genm, &itavs))
374         return NULL;
375 
376     msg = ossl_cmp_genp_new(srv_ctx->ctx, itavs);
377     sk_OSSL_CMP_ITAV_pop_free(itavs, OSSL_CMP_ITAV_free);
378     return msg;
379 }
380 
381 static OSSL_CMP_MSG *process_error(OSSL_CMP_SRV_CTX *srv_ctx,
382     const OSSL_CMP_MSG *req)
383 {
384     OSSL_CMP_ERRORMSGCONTENT *errorContent;
385     OSSL_CMP_MSG *msg;
386 
387     if (!ossl_assert(srv_ctx != NULL && srv_ctx->ctx != NULL && req != NULL))
388         return NULL;
389     errorContent = req->body->value.error;
390     srv_ctx->process_error(srv_ctx, req, errorContent->pKIStatusInfo,
391         errorContent->errorCode, errorContent->errorDetails);
392 
393     if ((msg = ossl_cmp_pkiconf_new(srv_ctx->ctx)) == NULL)
394         ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_CREATING_PKICONF);
395     return msg;
396 }
397 
398 static OSSL_CMP_MSG *process_certConf(OSSL_CMP_SRV_CTX *srv_ctx,
399     const OSSL_CMP_MSG *req)
400 {
401     OSSL_CMP_CTX *ctx;
402     OSSL_CMP_CERTCONFIRMCONTENT *ccc;
403     int num;
404     OSSL_CMP_MSG *msg = NULL;
405     OSSL_CMP_CERTSTATUS *status = NULL;
406 
407     if (!ossl_assert(srv_ctx != NULL && srv_ctx->ctx != NULL && req != NULL))
408         return NULL;
409 
410     ctx = srv_ctx->ctx;
411     ccc = req->body->value.certConf;
412     num = sk_OSSL_CMP_CERTSTATUS_num(ccc);
413 
414     if (OSSL_CMP_CTX_get_option(ctx, OSSL_CMP_OPT_IMPLICIT_CONFIRM) == 1
415         || ctx->status != OSSL_CMP_PKISTATUS_trans) {
416         ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_UNEXPECTED_CERTCONF);
417         return NULL;
418     }
419 
420     if (num == 0) {
421         ossl_cmp_err(ctx, "certificate rejected by client");
422     } else {
423         if (num > 1)
424             ossl_cmp_warn(ctx, "All CertStatus but the first will be ignored");
425         status = sk_OSSL_CMP_CERTSTATUS_value(ccc, 0);
426     }
427 
428     if (status != NULL) {
429         int certReqId = ossl_cmp_asn1_get_int(status->certReqId);
430         ASN1_OCTET_STRING *certHash = status->certHash;
431         OSSL_CMP_PKISI *si = status->statusInfo;
432 
433         if (certReqId != srv_ctx->certReqId) {
434             ERR_raise(ERR_LIB_CMP, CMP_R_BAD_REQUEST_ID);
435             return NULL;
436         }
437         if (!srv_ctx->process_certConf(srv_ctx, req, certReqId, certHash, si))
438             return NULL; /* reason code may be: CMP_R_CERTHASH_UNMATCHED */
439 
440         if (si != NULL
441             && ossl_cmp_pkisi_get_status(si) != OSSL_CMP_PKISTATUS_accepted) {
442             int pki_status = ossl_cmp_pkisi_get_status(si);
443             const char *str = ossl_cmp_PKIStatus_to_string(pki_status);
444 
445             ossl_cmp_log2(INFO, ctx, "certificate rejected by client %s %s",
446                 str == NULL ? "without" : "with",
447                 str == NULL ? "PKIStatus" : str);
448         }
449     }
450 
451     if ((msg = ossl_cmp_pkiconf_new(ctx)) == NULL)
452         ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_CREATING_PKICONF);
453     return msg;
454 }
455 
456 /* pollReq is handled separately, to avoid recursive call */
457 static OSSL_CMP_MSG *process_non_polling_request(OSSL_CMP_SRV_CTX *srv_ctx,
458     const OSSL_CMP_MSG *req)
459 {
460     OSSL_CMP_MSG *rsp = NULL;
461 
462     if (!ossl_assert(srv_ctx != NULL && srv_ctx->ctx != NULL && req != NULL
463             && req->body != NULL))
464         return NULL;
465 
466     switch (OSSL_CMP_MSG_get_bodytype(req)) {
467     case OSSL_CMP_PKIBODY_IR:
468     case OSSL_CMP_PKIBODY_CR:
469     case OSSL_CMP_PKIBODY_P10CR:
470     case OSSL_CMP_PKIBODY_KUR:
471         if (srv_ctx->process_cert_request == NULL)
472             ERR_raise(ERR_LIB_CMP, CMP_R_UNSUPPORTED_PKIBODY);
473         else
474             rsp = process_cert_request(srv_ctx, req);
475         break;
476     case OSSL_CMP_PKIBODY_RR:
477         if (srv_ctx->process_rr == NULL)
478             ERR_raise(ERR_LIB_CMP, CMP_R_UNSUPPORTED_PKIBODY);
479         else
480             rsp = process_rr(srv_ctx, req);
481         break;
482     case OSSL_CMP_PKIBODY_GENM:
483         if (srv_ctx->process_genm == NULL)
484             ERR_raise(ERR_LIB_CMP, CMP_R_UNSUPPORTED_PKIBODY);
485         else
486             rsp = process_genm(srv_ctx, req);
487         break;
488     case OSSL_CMP_PKIBODY_ERROR:
489         if (srv_ctx->process_error == NULL)
490             ERR_raise(ERR_LIB_CMP, CMP_R_UNSUPPORTED_PKIBODY);
491         else
492             rsp = process_error(srv_ctx, req);
493         break;
494     case OSSL_CMP_PKIBODY_CERTCONF:
495         if (srv_ctx->process_certConf == NULL)
496             ERR_raise(ERR_LIB_CMP, CMP_R_UNSUPPORTED_PKIBODY);
497         else
498             rsp = process_certConf(srv_ctx, req);
499         break;
500 
501     case OSSL_CMP_PKIBODY_POLLREQ:
502         ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
503         break;
504     default:
505         ERR_raise(ERR_LIB_CMP, CMP_R_UNSUPPORTED_PKIBODY);
506         break;
507     }
508 
509     return rsp;
510 }
511 
512 static OSSL_CMP_MSG *process_pollReq(OSSL_CMP_SRV_CTX *srv_ctx,
513     const OSSL_CMP_MSG *req)
514 {
515     OSSL_CMP_POLLREQCONTENT *prc;
516     OSSL_CMP_POLLREQ *pr;
517     int certReqId;
518     OSSL_CMP_MSG *orig_req;
519     int64_t check_after = 0;
520     OSSL_CMP_MSG *msg = NULL;
521 
522     if (!ossl_assert(srv_ctx != NULL && srv_ctx->ctx != NULL && req != NULL))
523         return NULL;
524 
525     if (!srv_ctx->polling) {
526         ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
527         return NULL;
528     }
529 
530     prc = req->body->value.pollReq;
531     if (sk_OSSL_CMP_POLLREQ_num(prc) != 1) {
532         ERR_raise(ERR_LIB_CMP, CMP_R_MULTIPLE_REQUESTS_NOT_SUPPORTED);
533         return NULL;
534     }
535 
536     pr = sk_OSSL_CMP_POLLREQ_value(prc, 0);
537     certReqId = ossl_cmp_asn1_get_int(pr->certReqId);
538     if (!srv_ctx->process_pollReq(srv_ctx, req, certReqId,
539             &orig_req, &check_after))
540         return NULL;
541 
542     if (orig_req != NULL) {
543         srv_ctx->polling = 0;
544         msg = process_non_polling_request(srv_ctx, orig_req);
545         OSSL_CMP_MSG_free(orig_req);
546     } else {
547         if ((msg = ossl_cmp_pollRep_new(srv_ctx->ctx, certReqId,
548                  check_after))
549             == NULL)
550             ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_CREATING_POLLREP);
551     }
552     return msg;
553 }
554 
555 /*
556  * Determine whether missing/invalid protection of request message is allowed.
557  * Return 1 on acceptance, 0 on rejection, or -1 on (internal) error.
558  */
559 static int unprotected_exception(const OSSL_CMP_CTX *ctx,
560     const OSSL_CMP_MSG *req,
561     int invalid_protection,
562     int accept_unprotected_requests)
563 {
564     if (!ossl_assert(ctx != NULL && req != NULL))
565         return -1;
566 
567     if (accept_unprotected_requests) {
568         ossl_cmp_log1(WARN, ctx, "ignoring %s protection of request message",
569             invalid_protection ? "invalid" : "missing");
570         return 1;
571     }
572     if (OSSL_CMP_MSG_get_bodytype(req) == OSSL_CMP_PKIBODY_ERROR
573         && OSSL_CMP_CTX_get_option(ctx, OSSL_CMP_OPT_UNPROTECTED_ERRORS) == 1) {
574         ossl_cmp_warn(ctx, "ignoring missing protection of error message");
575         return 1;
576     }
577     return 0;
578 }
579 
580 /*
581  * returns created message and NULL on internal error
582  */
583 OSSL_CMP_MSG *OSSL_CMP_SRV_process_request(OSSL_CMP_SRV_CTX *srv_ctx,
584     const OSSL_CMP_MSG *req)
585 {
586     OSSL_CMP_CTX *ctx;
587     ASN1_OCTET_STRING *backup_secret;
588     OSSL_CMP_PKIHEADER *hdr;
589     int req_type, rsp_type;
590     int req_verified = 0;
591     OSSL_CMP_MSG *rsp = NULL;
592 
593     if (srv_ctx == NULL || srv_ctx->ctx == NULL
594         || req == NULL || req->body == NULL
595         || (hdr = OSSL_CMP_MSG_get0_header(req)) == NULL) {
596         ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
597         return 0;
598     }
599     ctx = srv_ctx->ctx;
600     backup_secret = ctx->secretValue;
601     req_type = OSSL_CMP_MSG_get_bodytype(req);
602     ossl_cmp_log1(DEBUG, ctx,
603         "received %s", ossl_cmp_bodytype_to_string(req_type));
604 
605     /*
606      * Some things need to be done already before validating the message in
607      * order to be able to send an error message as far as needed and possible.
608      */
609     if (hdr->sender->type != GEN_DIRNAME) {
610         ERR_raise(ERR_LIB_CMP, CMP_R_SENDER_GENERALNAME_TYPE_NOT_SUPPORTED);
611         goto err;
612     }
613     if (!OSSL_CMP_CTX_set1_recipient(ctx, hdr->sender->d.directoryName))
614         goto err;
615 
616     if (srv_ctx->polling && req_type != OSSL_CMP_PKIBODY_POLLREQ
617         && req_type != OSSL_CMP_PKIBODY_ERROR) {
618         ERR_raise(ERR_LIB_CMP, CMP_R_EXPECTED_POLLREQ);
619         goto err;
620     }
621 
622     switch (req_type) {
623     case OSSL_CMP_PKIBODY_IR:
624     case OSSL_CMP_PKIBODY_CR:
625     case OSSL_CMP_PKIBODY_P10CR:
626     case OSSL_CMP_PKIBODY_KUR:
627     case OSSL_CMP_PKIBODY_RR:
628     case OSSL_CMP_PKIBODY_GENM:
629     case OSSL_CMP_PKIBODY_ERROR:
630         if (ctx->transactionID != NULL) {
631             char *tid = i2s_ASN1_OCTET_STRING(NULL, ctx->transactionID);
632 
633             if (tid != NULL)
634                 ossl_cmp_log1(WARN, ctx,
635                     "Assuming that last transaction with ID=%s got aborted",
636                     tid);
637             OPENSSL_free(tid);
638         }
639         /* start of a new transaction, reset transactionID and senderNonce */
640         if (!OSSL_CMP_CTX_set1_transactionID(ctx, NULL)
641             || !OSSL_CMP_CTX_set1_senderNonce(ctx, NULL))
642             goto err;
643 
644         if (srv_ctx->clean_transaction != NULL
645             && !srv_ctx->clean_transaction(srv_ctx, NULL)) {
646             ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_PROCESSING_MESSAGE);
647             goto err;
648         }
649 
650         break;
651     default:
652         /* transactionID should be already initialized */
653         if (ctx->transactionID == NULL) {
654 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
655             ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PKIBODY);
656             goto err;
657 #endif
658         }
659     }
660 
661     req_verified = ossl_cmp_msg_check_update(ctx, req, unprotected_exception,
662         srv_ctx->acceptUnprotected);
663     if (ctx->secretValue != NULL && ctx->pkey != NULL
664         && ossl_cmp_hdr_get_protection_nid(hdr) != NID_id_PasswordBasedMAC)
665         ctx->secretValue = NULL; /* use MSG_SIG_ALG when protecting rsp */
666     if (!req_verified)
667         goto err;
668 
669     if (req_type == OSSL_CMP_PKIBODY_POLLREQ) {
670         if (srv_ctx->process_pollReq == NULL)
671             ERR_raise(ERR_LIB_CMP, CMP_R_UNSUPPORTED_PKIBODY);
672         else
673             rsp = process_pollReq(srv_ctx, req);
674     } else {
675         if (srv_ctx->delayed_delivery != NULL
676             && (rsp = delayed_delivery(srv_ctx, req)) != NULL) {
677             goto err;
678         }
679         rsp = process_non_polling_request(srv_ctx, req);
680     }
681 
682 err:
683     if (rsp == NULL) {
684         /* on error, try to respond with CMP error message to client */
685         const char *data = NULL, *reason = NULL;
686         int flags = 0;
687         unsigned long err = ERR_peek_error_data(&data, &flags);
688         int fail_info = 1 << OSSL_CMP_PKIFAILUREINFO_badRequest;
689         /* fail_info is not very specific */
690         OSSL_CMP_PKISI *si = NULL;
691 
692         if (!req_verified) {
693             /*
694              * Above ossl_cmp_msg_check_update() was not successfully executed,
695              * which normally would set ctx->transactionID and ctx->recipNonce.
696              * So anyway try to provide the right transactionID and recipNonce,
697              * while ignoring any (extra) error in next two function calls.
698              */
699             if (ctx->transactionID == NULL)
700                 (void)OSSL_CMP_CTX_set1_transactionID(ctx, hdr->transactionID);
701             (void)ossl_cmp_ctx_set1_recipNonce(ctx, hdr->senderNonce);
702         }
703 
704         if ((flags & ERR_TXT_STRING) == 0 || *data == '\0')
705             data = NULL;
706         reason = ERR_reason_error_string(err);
707         if ((si = OSSL_CMP_STATUSINFO_new(OSSL_CMP_PKISTATUS_rejection,
708                  fail_info, reason))
709             != NULL) {
710             rsp = ossl_cmp_error_new(srv_ctx->ctx, si, err,
711                 data, srv_ctx->sendUnprotectedErrors);
712             OSSL_CMP_PKISI_free(si);
713         }
714     }
715     OSSL_CMP_CTX_print_errors(ctx);
716     ctx->secretValue = backup_secret;
717 
718     rsp_type = rsp != NULL ? OSSL_CMP_MSG_get_bodytype(rsp) : OSSL_CMP_PKIBODY_ERROR;
719     if (rsp != NULL)
720         ossl_cmp_log1(DEBUG, ctx,
721             "sending %s", ossl_cmp_bodytype_to_string(rsp_type));
722     else
723         ossl_cmp_log(ERR, ctx, "cannot send proper CMP response");
724 
725     /* determine whether to keep the transaction open or not */
726     ctx->status = OSSL_CMP_PKISTATUS_trans;
727     switch (rsp_type) {
728     case OSSL_CMP_PKIBODY_IP:
729     case OSSL_CMP_PKIBODY_CP:
730     case OSSL_CMP_PKIBODY_KUP:
731         if (OSSL_CMP_CTX_get_option(ctx, OSSL_CMP_OPT_IMPLICIT_CONFIRM) == 0)
732             break;
733         /* fall through */
734 
735     case OSSL_CMP_PKIBODY_ERROR:
736         if (rsp != NULL && ossl_cmp_is_error_with_waiting(rsp))
737             break;
738         /* fall through */
739 
740     case OSSL_CMP_PKIBODY_RP:
741     case OSSL_CMP_PKIBODY_PKICONF:
742     case OSSL_CMP_PKIBODY_GENP:
743         /* Other terminating response message types are not supported */
744         srv_ctx->certReqId = OSSL_CMP_CERTREQID_INVALID;
745         /* Prepare for next transaction, ignoring any errors here: */
746         if (srv_ctx->clean_transaction != NULL)
747             (void)srv_ctx->clean_transaction(srv_ctx, ctx->transactionID);
748         (void)OSSL_CMP_CTX_set1_transactionID(ctx, NULL);
749         (void)OSSL_CMP_CTX_set1_senderNonce(ctx, NULL);
750         ctx->status = OSSL_CMP_PKISTATUS_unspecified; /* transaction closed */
751 
752     default: /* not closing transaction in other cases */
753         break;
754     }
755     return rsp;
756 }
757 
758 /*
759  * Server interface that may substitute OSSL_CMP_MSG_http_perform at the client.
760  * The OSSL_CMP_SRV_CTX must be set as client_ctx->transfer_cb_arg.
761  * returns received message on success, else NULL and pushes an element on the
762  * error stack.
763  */
764 OSSL_CMP_MSG *OSSL_CMP_CTX_server_perform(OSSL_CMP_CTX *client_ctx,
765     const OSSL_CMP_MSG *req)
766 {
767     OSSL_CMP_SRV_CTX *srv_ctx = NULL;
768 
769     if (client_ctx == NULL || req == NULL) {
770         ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
771         return NULL;
772     }
773 
774     if ((srv_ctx = OSSL_CMP_CTX_get_transfer_cb_arg(client_ctx)) == NULL) {
775         ERR_raise(ERR_LIB_CMP, CMP_R_TRANSFER_ERROR);
776         return NULL;
777     }
778 
779     return OSSL_CMP_SRV_process_request(srv_ctx, req);
780 }
781