xref: /openssl/crypto/cmp/cmp_vfy.c (revision b893ceef)
1 /*
2  * Copyright 2007-2024 The OpenSSL Project Authors. All Rights Reserved.
3  * Copyright Nokia 2007-2020
4  * Copyright Siemens AG 2015-2020
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 /* CMP functions for PKIMessage checking */
13 
14 #include "cmp_local.h"
15 #include <openssl/cmp_util.h>
16 
17 /* explicit #includes not strictly needed since implied by the above: */
18 #include <openssl/asn1t.h>
19 #include <openssl/cmp.h>
20 #include <openssl/crmf.h>
21 #include <openssl/err.h>
22 #include <openssl/x509.h>
23 
24 /* Verify a message protected by signature according to RFC section 5.1.3.3 */
verify_signature(const OSSL_CMP_CTX * cmp_ctx,const OSSL_CMP_MSG * msg,X509 * cert)25 static int verify_signature(const OSSL_CMP_CTX *cmp_ctx,
26                             const OSSL_CMP_MSG *msg, X509 *cert)
27 {
28     OSSL_CMP_PROTECTEDPART prot_part;
29     EVP_PKEY *pubkey = NULL;
30     BIO *bio;
31     int res = 0;
32 
33     if (!ossl_assert(cmp_ctx != NULL && msg != NULL && cert != NULL))
34         return 0;
35 
36     bio = BIO_new(BIO_s_mem()); /* may be NULL */
37     if (bio == NULL)
38         return 0;
39     /* verify that keyUsage, if present, contains digitalSignature */
40     if (!cmp_ctx->ignore_keyusage
41             && (X509_get_key_usage(cert) & X509v3_KU_DIGITAL_SIGNATURE) == 0) {
42         ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_KEY_USAGE_DIGITALSIGNATURE);
43         goto sig_err;
44     }
45 
46     pubkey = X509_get_pubkey(cert);
47     if (pubkey == NULL) {
48         ERR_raise(ERR_LIB_CMP, CMP_R_FAILED_EXTRACTING_PUBKEY);
49         goto sig_err;
50     }
51 
52     prot_part.header = msg->header;
53     prot_part.body = msg->body;
54 
55     if (ASN1_item_verify_ex(ASN1_ITEM_rptr(OSSL_CMP_PROTECTEDPART),
56                             msg->header->protectionAlg, msg->protection,
57                             &prot_part, NULL, pubkey, cmp_ctx->libctx,
58                             cmp_ctx->propq) > 0) {
59         res = 1;
60         goto end;
61     }
62 
63  sig_err:
64     res = ossl_x509_print_ex_brief(bio, cert, X509_FLAG_NO_EXTENSIONS);
65     ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_VALIDATING_SIGNATURE);
66     if (res)
67         ERR_add_error_mem_bio("\n", bio);
68     res = 0;
69 
70  end:
71     EVP_PKEY_free(pubkey);
72     BIO_free(bio);
73 
74     return res;
75 }
76 
77 /* Verify a message protected with PBMAC */
verify_PBMAC(OSSL_CMP_CTX * ctx,const OSSL_CMP_MSG * msg)78 static int verify_PBMAC(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)
79 {
80     ASN1_BIT_STRING *protection = NULL;
81     int valid = 0;
82 
83     /* generate expected protection for the message */
84     if ((protection = ossl_cmp_calc_protection(ctx, msg)) == NULL)
85         return 0; /* failed to generate protection string! */
86 
87     valid = msg->protection != NULL && msg->protection->length >= 0
88             && msg->protection->type == protection->type
89             && msg->protection->length == protection->length
90             && CRYPTO_memcmp(msg->protection->data, protection->data,
91                              protection->length) == 0;
92     ASN1_BIT_STRING_free(protection);
93     if (!valid)
94         ERR_raise(ERR_LIB_CMP, CMP_R_WRONG_PBM_VALUE);
95 
96     return valid;
97 }
98 
99 /*-
100  * Attempt to validate certificate and path using any given store with trusted
101  * certs (possibly including CRLs and a cert verification callback function)
102  * and non-trusted intermediate certs from the given ctx.
103  *
104  * Returns 1 on successful validation and 0 otherwise.
105  */
OSSL_CMP_validate_cert_path(const OSSL_CMP_CTX * ctx,X509_STORE * trusted_store,X509 * cert)106 int OSSL_CMP_validate_cert_path(const OSSL_CMP_CTX *ctx,
107                                 X509_STORE *trusted_store, X509 *cert)
108 {
109     int valid = 0;
110     X509_STORE_CTX *csc = NULL;
111     int err;
112 
113     if (ctx == NULL || cert == NULL) {
114         ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
115         return 0;
116     }
117 
118     if (trusted_store == NULL) {
119         ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_TRUST_STORE);
120         return 0;
121     }
122 
123     if ((csc = X509_STORE_CTX_new_ex(ctx->libctx, ctx->propq)) == NULL
124             || !X509_STORE_CTX_init(csc, trusted_store,
125                                     cert, ctx->untrusted))
126         goto err;
127 
128     valid = X509_verify_cert(csc) > 0;
129 
130     /* make sure suitable error is queued even if callback did not do */
131     err = ERR_peek_last_error();
132     if (!valid && ERR_GET_REASON(err) != CMP_R_POTENTIALLY_INVALID_CERTIFICATE)
133         ERR_raise(ERR_LIB_CMP, CMP_R_POTENTIALLY_INVALID_CERTIFICATE);
134 
135  err:
136     /* directly output any fresh errors, needed for check_msg_find_cert() */
137     OSSL_CMP_CTX_print_errors(ctx);
138     X509_STORE_CTX_free(csc);
139     return valid;
140 }
141 
verify_cb_cert(X509_STORE * ts,X509 * cert,int err)142 static int verify_cb_cert(X509_STORE *ts, X509 *cert, int err)
143 {
144     X509_STORE_CTX_verify_cb verify_cb;
145     X509_STORE_CTX *csc;
146     int ok = 0;
147 
148     if (ts == NULL || (verify_cb = X509_STORE_get_verify_cb(ts)) == NULL)
149         return ok;
150     if ((csc = X509_STORE_CTX_new()) != NULL
151             && X509_STORE_CTX_init(csc, ts, cert, NULL)) {
152         X509_STORE_CTX_set_error(csc, err);
153         X509_STORE_CTX_set_current_cert(csc, cert);
154         ok = (*verify_cb)(0, csc);
155     }
156     X509_STORE_CTX_free(csc);
157     return ok;
158 }
159 
160 /* Return 0 if expect_name != NULL and there is no matching actual_name */
check_name(const OSSL_CMP_CTX * ctx,int log_success,const char * actual_desc,const X509_NAME * actual_name,const char * expect_desc,const X509_NAME * expect_name)161 static int check_name(const OSSL_CMP_CTX *ctx, int log_success,
162                       const char *actual_desc, const X509_NAME *actual_name,
163                       const char *expect_desc, const X509_NAME *expect_name)
164 {
165     char *str;
166 
167     if (expect_name == NULL)
168         return 1; /* no expectation, thus trivially fulfilled */
169 
170     /* make sure that a matching name is there */
171     if (actual_name == NULL) {
172         ossl_cmp_log1(WARN, ctx, "missing %s", actual_desc);
173         return 0;
174     }
175     str = X509_NAME_oneline(actual_name, NULL, 0);
176     if (X509_NAME_cmp(actual_name, expect_name) == 0) {
177         if (log_success && str != NULL)
178             ossl_cmp_log3(INFO, ctx, " %s matches %s: %s",
179                           actual_desc, expect_desc, str);
180         OPENSSL_free(str);
181         return 1;
182     }
183 
184     if (str != NULL)
185         ossl_cmp_log2(INFO, ctx, " actual name in %s = %s", actual_desc, str);
186     OPENSSL_free(str);
187     if ((str = X509_NAME_oneline(expect_name, NULL, 0)) != NULL)
188         ossl_cmp_log2(INFO, ctx, " does not match %s = %s", expect_desc, str);
189     OPENSSL_free(str);
190     return 0;
191 }
192 
193 /* Return 0 if skid != NULL and there is no matching subject key ID in cert */
check_kid(const OSSL_CMP_CTX * ctx,const ASN1_OCTET_STRING * ckid,const ASN1_OCTET_STRING * skid)194 static int check_kid(const OSSL_CMP_CTX *ctx,
195                      const ASN1_OCTET_STRING *ckid,
196                      const ASN1_OCTET_STRING *skid)
197 {
198     char *str;
199 
200     if (skid == NULL)
201         return 1; /* no expectation, thus trivially fulfilled */
202 
203     /* make sure that the expected subject key identifier is there */
204     if (ckid == NULL) {
205         ossl_cmp_warn(ctx, "missing Subject Key Identifier in certificate");
206         return 0;
207     }
208     str = i2s_ASN1_OCTET_STRING(NULL, ckid);
209     if (ASN1_OCTET_STRING_cmp(ckid, skid) == 0) {
210         if (str != NULL)
211             ossl_cmp_log1(INFO, ctx, " subjectKID matches senderKID: %s", str);
212         OPENSSL_free(str);
213         return 1;
214     }
215 
216     if (str != NULL)
217         ossl_cmp_log1(INFO, ctx, " cert Subject Key Identifier = %s", str);
218     OPENSSL_free(str);
219     if ((str = i2s_ASN1_OCTET_STRING(NULL, skid)) != NULL)
220         ossl_cmp_log1(INFO, ctx, " does not match senderKID    = %s", str);
221     OPENSSL_free(str);
222     return 0;
223 }
224 
already_checked(const X509 * cert,const STACK_OF (X509)* already_checked)225 static int already_checked(const X509 *cert,
226                            const STACK_OF(X509) *already_checked)
227 {
228     int i;
229 
230     for (i = sk_X509_num(already_checked /* may be NULL */); i > 0; i--)
231         if (X509_cmp(sk_X509_value(already_checked, i - 1), cert) == 0)
232             return 1;
233     return 0;
234 }
235 
236 /*-
237  * Check if the given cert is acceptable as sender cert of the given message.
238  * The subject DN must match, the subject key ID as well if present in the msg,
239  * and the cert must be current (checked if ctx->trusted is not NULL).
240  * Note that cert revocation etc. is checked by OSSL_CMP_validate_cert_path().
241  *
242  * Returns 0 on error or not acceptable, else 1.
243  */
cert_acceptable(const OSSL_CMP_CTX * ctx,const char * desc1,const char * desc2,X509 * cert,const STACK_OF (X509)* already_checked1,const STACK_OF (X509)* already_checked2,const OSSL_CMP_MSG * msg)244 static int cert_acceptable(const OSSL_CMP_CTX *ctx,
245                            const char *desc1, const char *desc2, X509 *cert,
246                            const STACK_OF(X509) *already_checked1,
247                            const STACK_OF(X509) *already_checked2,
248                            const OSSL_CMP_MSG *msg)
249 {
250     X509_STORE *ts = ctx->trusted;
251     int self_issued = X509_check_issued(cert, cert) == X509_V_OK;
252     char *str;
253     X509_VERIFY_PARAM *vpm = ts != NULL ? X509_STORE_get0_param(ts) : NULL;
254     int time_cmp;
255 
256     ossl_cmp_log3(INFO, ctx, " considering %s%s %s with..",
257                   self_issued ? "self-issued ": "", desc1, desc2);
258     if ((str = X509_NAME_oneline(X509_get_subject_name(cert), NULL, 0)) != NULL)
259         ossl_cmp_log1(INFO, ctx, "  subject = %s", str);
260     OPENSSL_free(str);
261     if (!self_issued) {
262         str = X509_NAME_oneline(X509_get_issuer_name(cert), NULL, 0);
263         if (str != NULL)
264             ossl_cmp_log1(INFO, ctx, "  issuer  = %s", str);
265         OPENSSL_free(str);
266     }
267 
268     if (already_checked(cert, already_checked1)
269             || already_checked(cert, already_checked2)) {
270         ossl_cmp_info(ctx, " cert has already been checked");
271         return 0;
272     }
273 
274     time_cmp = X509_cmp_timeframe(vpm, X509_get0_notBefore(cert),
275                                   X509_get0_notAfter(cert));
276     if (time_cmp != 0) {
277         int err = time_cmp > 0 ? X509_V_ERR_CERT_HAS_EXPIRED
278                                : X509_V_ERR_CERT_NOT_YET_VALID;
279 
280         ossl_cmp_warn(ctx, time_cmp > 0 ? "cert has expired"
281                                         : "cert is not yet valid");
282         if (ctx->log_cb != NULL /* logging not temporarily disabled */
283                 && verify_cb_cert(ts, cert, err) <= 0)
284             return 0;
285     }
286 
287     if (!check_name(ctx, 1,
288                     "cert subject", X509_get_subject_name(cert),
289                     "sender field", msg->header->sender->d.directoryName))
290         return 0;
291 
292     if (!check_kid(ctx, X509_get0_subject_key_id(cert), msg->header->senderKID))
293         return 0;
294     /* prevent misleading error later in case x509v3_cache_extensions() fails */
295     if (!ossl_x509v3_cache_extensions(cert)) {
296         ossl_cmp_warn(ctx, "cert appears to be invalid");
297         return 0;
298     }
299     if (!verify_signature(ctx, msg, cert)) {
300         ossl_cmp_warn(ctx, "msg signature verification failed");
301         return 0;
302     }
303     /* acceptable also if there is no senderKID in msg header */
304     ossl_cmp_info(ctx, " cert seems acceptable");
305     return 1;
306 }
307 
check_cert_path(const OSSL_CMP_CTX * ctx,X509_STORE * store,X509 * scrt)308 static int check_cert_path(const OSSL_CMP_CTX *ctx, X509_STORE *store,
309                            X509 *scrt)
310 {
311     if (OSSL_CMP_validate_cert_path(ctx, store, scrt))
312         return 1;
313 
314     ossl_cmp_warn(ctx,
315                   "msg signature validates but cert path validation failed");
316     return 0;
317 }
318 
319 /*
320  * Exceptional handling for 3GPP TS 33.310 [3G/LTE Network Domain Security
321  * (NDS); Authentication Framework (AF)], only to use for IP messages
322  * and if the ctx option is explicitly set: use self-issued certificates
323  * from extraCerts as trust anchor to validate sender cert -
324  * provided it also can validate the newly enrolled certificate
325  */
check_cert_path_3gpp(const OSSL_CMP_CTX * ctx,const OSSL_CMP_MSG * msg,X509 * scrt)326 static int check_cert_path_3gpp(const OSSL_CMP_CTX *ctx,
327                                 const OSSL_CMP_MSG *msg, X509 *scrt)
328 {
329     int valid = 0;
330     X509_STORE *store;
331 
332     if (!ctx->permitTAInExtraCertsForIR)
333         return 0;
334 
335     if ((store = X509_STORE_new()) == NULL
336             || !ossl_cmp_X509_STORE_add1_certs(store, msg->extraCerts,
337                                                1 /* self-issued only */))
338         goto err;
339 
340     /* store does not include CRLs */
341     valid = OSSL_CMP_validate_cert_path(ctx, store, scrt);
342     if (!valid) {
343         ossl_cmp_warn(ctx,
344                       "also exceptional 3GPP mode cert path validation failed");
345     } else {
346         /*
347          * verify that the newly enrolled certificate (which assumed rid ==
348          * OSSL_CMP_CERTREQID) can also be validated with the same trusted store
349          */
350         OSSL_CMP_CERTRESPONSE *crep =
351             ossl_cmp_certrepmessage_get0_certresponse(msg->body->value.ip,
352                                                       OSSL_CMP_CERTREQID);
353         X509 *newcrt = ossl_cmp_certresponse_get1_cert(ctx, crep);
354 
355         /*
356          * maybe better use get_cert_status() from cmp_client.c, which catches
357          * errors
358          */
359         valid = OSSL_CMP_validate_cert_path(ctx, store, newcrt);
360         X509_free(newcrt);
361     }
362 
363  err:
364     X509_STORE_free(store);
365     return valid;
366 }
367 
check_msg_given_cert(const OSSL_CMP_CTX * ctx,X509 * cert,const OSSL_CMP_MSG * msg)368 static int check_msg_given_cert(const OSSL_CMP_CTX *ctx, X509 *cert,
369                                 const OSSL_CMP_MSG *msg)
370 {
371     return cert_acceptable(ctx, "previously validated", "sender cert",
372                            cert, NULL, NULL, msg)
373         && (check_cert_path(ctx, ctx->trusted, cert)
374             || check_cert_path_3gpp(ctx, msg, cert));
375 }
376 
377 /*-
378  * Try all certs in given list for verifying msg, normally or in 3GPP mode.
379  * If already_checked1 == NULL then certs are assumed to be the msg->extraCerts.
380  * On success cache the found cert using ossl_cmp_ctx_set1_validatedSrvCert().
381  */
check_msg_with_certs(OSSL_CMP_CTX * ctx,const STACK_OF (X509)* certs,const char * desc,const STACK_OF (X509)* already_checked1,const STACK_OF (X509)* already_checked2,const OSSL_CMP_MSG * msg,int mode_3gpp)382 static int check_msg_with_certs(OSSL_CMP_CTX *ctx, const STACK_OF(X509) *certs,
383                                 const char *desc,
384                                 const STACK_OF(X509) *already_checked1,
385                                 const STACK_OF(X509) *already_checked2,
386                                 const OSSL_CMP_MSG *msg, int mode_3gpp)
387 {
388     int in_extraCerts = already_checked1 == NULL;
389     int n_acceptable_certs = 0;
390     int i;
391 
392     if (sk_X509_num(certs) <= 0) {
393         ossl_cmp_log1(WARN, ctx, "no %s", desc);
394         return 0;
395     }
396 
397     for (i = 0; i < sk_X509_num(certs); i++) { /* certs may be NULL */
398         X509 *cert = sk_X509_value(certs, i);
399 
400         if (!ossl_assert(cert != NULL))
401             return 0;
402         if (!cert_acceptable(ctx, "cert from", desc, cert,
403                              already_checked1, already_checked2, msg))
404             continue;
405         n_acceptable_certs++;
406         if (mode_3gpp ? check_cert_path_3gpp(ctx, msg, cert)
407                       : check_cert_path(ctx, ctx->trusted, cert)) {
408             /* store successful sender cert for further msgs in transaction */
409             return ossl_cmp_ctx_set1_validatedSrvCert(ctx, cert);
410         }
411     }
412     if (in_extraCerts && n_acceptable_certs == 0)
413         ossl_cmp_warn(ctx, "no acceptable cert in extraCerts");
414     return 0;
415 }
416 
417 /*-
418  * Verify msg trying first ctx->untrusted, which should include extraCerts
419  * at its front, then trying the trusted certs in truststore (if any) of ctx.
420  * On success cache the found cert using ossl_cmp_ctx_set1_validatedSrvCert().
421  */
check_msg_all_certs(OSSL_CMP_CTX * ctx,const OSSL_CMP_MSG * msg,int mode_3gpp)422 static int check_msg_all_certs(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg,
423                                int mode_3gpp)
424 {
425     int ret = 0;
426 
427     if (ctx->permitTAInExtraCertsForIR
428             && OSSL_CMP_MSG_get_bodytype(msg) == OSSL_CMP_PKIBODY_IP)
429         ossl_cmp_info(ctx, mode_3gpp ?
430                       "normal mode failed; trying now 3GPP mode trusting extraCerts"
431                       : "trying first normal mode using trust store");
432     else if (mode_3gpp)
433         return 0;
434 
435     if (check_msg_with_certs(ctx, msg->extraCerts, "extraCerts",
436                              NULL, NULL, msg, mode_3gpp))
437         return 1;
438     if (check_msg_with_certs(ctx, ctx->untrusted, "untrusted certs",
439                              msg->extraCerts, NULL, msg, mode_3gpp))
440         return 1;
441 
442     if (ctx->trusted == NULL) {
443         ossl_cmp_warn(ctx, mode_3gpp ? "no self-issued extraCerts"
444                                      : "no trusted store");
445     } else {
446         STACK_OF(X509) *trusted = X509_STORE_get1_all_certs(ctx->trusted);
447 
448         ret = check_msg_with_certs(ctx, trusted,
449                                    mode_3gpp ? "self-issued extraCerts"
450                                              : "certs in trusted store",
451                                    msg->extraCerts, ctx->untrusted,
452                                    msg, mode_3gpp);
453         OSSL_STACK_OF_X509_free(trusted);
454     }
455     return ret;
456 }
457 
458 /*-
459  * Verify message signature with any acceptable and valid candidate cert.
460  * On success cache the found cert using ossl_cmp_ctx_set1_validatedSrvCert().
461  */
check_msg_find_cert(OSSL_CMP_CTX * ctx,const OSSL_CMP_MSG * msg)462 static int check_msg_find_cert(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)
463 {
464     X509 *scrt = ctx->validatedSrvCert; /* previous successful sender cert */
465     GENERAL_NAME *sender = msg->header->sender;
466     char *sname = NULL;
467     char *skid_str = NULL;
468     const ASN1_OCTET_STRING *skid = msg->header->senderKID;
469     OSSL_CMP_log_cb_t backup_log_cb = ctx->log_cb;
470     int res = 0;
471 
472     if (sender == NULL || msg->body == NULL)
473         return 0; /* other NULL cases already have been checked */
474     if (sender->type != GEN_DIRNAME) {
475         /* So far, only X509_NAME is supported */
476         ERR_raise(ERR_LIB_CMP, CMP_R_SENDER_GENERALNAME_TYPE_NOT_SUPPORTED);
477         return 0;
478     }
479 
480     /* dump any hitherto errors to avoid confusion when printing further ones */
481     OSSL_CMP_CTX_print_errors(ctx);
482 
483     /* enable clearing irrelevant errors in attempts to validate sender certs */
484     (void)ERR_set_mark();
485     ctx->log_cb = NULL; /* temporarily disable logging */
486 
487     /*
488      * try first cached scrt, used successfully earlier in same transaction,
489      * for validating this and any further msgs where extraCerts may be left out
490      */
491     if (scrt != NULL) {
492         if (check_msg_given_cert(ctx, scrt, msg)) {
493             ctx->log_cb = backup_log_cb;
494             (void)ERR_pop_to_mark();
495             return 1;
496         }
497         /* cached sender cert has shown to be no more successfully usable */
498         (void)ossl_cmp_ctx_set1_validatedSrvCert(ctx, NULL);
499         /* re-do the above check (just) for adding diagnostic information */
500         ossl_cmp_info(ctx,
501                       "trying to verify msg signature with previously validated cert");
502         (void)check_msg_given_cert(ctx, scrt, msg);
503     }
504 
505     res = check_msg_all_certs(ctx, msg, 0 /* using ctx->trusted */)
506             || check_msg_all_certs(ctx, msg, 1 /* 3gpp */);
507     ctx->log_cb = backup_log_cb;
508     if (res) {
509         /* discard any diagnostic information on trying to use certs */
510         (void)ERR_pop_to_mark();
511         goto end;
512     }
513     /* failed finding a sender cert that verifies the message signature */
514     (void)ERR_clear_last_mark();
515 
516     sname = X509_NAME_oneline(sender->d.directoryName, NULL, 0);
517     skid_str = skid == NULL ? NULL : i2s_ASN1_OCTET_STRING(NULL, skid);
518     if (ctx->log_cb != NULL) {
519         ossl_cmp_info(ctx, "trying to verify msg signature with a valid cert that..");
520         if (sname != NULL)
521             ossl_cmp_log1(INFO, ctx, "matches msg sender    = %s", sname);
522         if (skid_str != NULL)
523             ossl_cmp_log1(INFO, ctx, "matches msg senderKID = %s", skid_str);
524         else
525             ossl_cmp_info(ctx, "while msg header does not contain senderKID");
526         /* re-do the above checks (just) for adding diagnostic information */
527         (void)check_msg_all_certs(ctx, msg, 0 /* using ctx->trusted */);
528         (void)check_msg_all_certs(ctx, msg, 1 /* 3gpp */);
529     }
530 
531     ERR_raise(ERR_LIB_CMP, CMP_R_NO_SUITABLE_SENDER_CERT);
532     if (sname != NULL) {
533         ERR_add_error_txt(NULL, "for msg sender name = ");
534         ERR_add_error_txt(NULL, sname);
535     }
536     if (skid_str != NULL) {
537         ERR_add_error_txt(" and ", "for msg senderKID = ");
538         ERR_add_error_txt(NULL, skid_str);
539     }
540 
541  end:
542     OPENSSL_free(sname);
543     OPENSSL_free(skid_str);
544     return res;
545 }
546 
547 /*-
548  * Validate the protection of the given PKIMessage using either password-
549  * based mac (PBM) or a signature algorithm. In the case of signature algorithm,
550  * the sender certificate can have been pinned by providing it in ctx->srvCert,
551  * else it is searched in msg->extraCerts, ctx->untrusted, in ctx->trusted
552  * (in this order) and is path is validated against ctx->trusted.
553  * On success cache the found cert using ossl_cmp_ctx_set1_validatedSrvCert().
554  *
555  * If ctx->permitTAInExtraCertsForIR is true and when validating a CMP IP msg,
556  * the trust anchor for validating the IP msg may be taken from msg->extraCerts
557  * if a self-issued certificate is found there that can be used to
558  * validate the enrolled certificate returned in the IP.
559  * This is according to the need given in 3GPP TS 33.310.
560  *
561  * Returns 1 on success, 0 on error or validation failed.
562  */
OSSL_CMP_validate_msg(OSSL_CMP_CTX * ctx,const OSSL_CMP_MSG * msg)563 int OSSL_CMP_validate_msg(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)
564 {
565     X509 *scrt;
566 
567     ossl_cmp_debug(ctx, "validating CMP message");
568     if (ctx == NULL || msg == NULL
569             || msg->header == NULL || msg->body == NULL) {
570         ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
571         return 0;
572     }
573 
574     if (msg->header->protectionAlg == NULL /* unprotected message */
575             || msg->protection == NULL || msg->protection->data == NULL) {
576         ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_PROTECTION);
577         return 0;
578     }
579 
580     switch (ossl_cmp_hdr_get_protection_nid(msg->header)) {
581         /* 5.1.3.1.  Shared Secret Information */
582     case NID_id_PasswordBasedMAC:
583         if (ctx->secretValue == NULL) {
584             ossl_cmp_info(ctx, "no secret available for verifying PBM-based CMP message protection");
585             ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_SECRET);
586             return 0;
587         }
588         if (verify_PBMAC(ctx, msg)) {
589             /*
590              * RFC 4210, 5.3.2: 'Note that if the PKI Message Protection is
591              * "shared secret information", then any certificate transported in
592              * the caPubs field may be directly trusted as a root CA
593              * certificate by the initiator.'
594              */
595             switch (OSSL_CMP_MSG_get_bodytype(msg)) {
596             case -1:
597                 return 0;
598             case OSSL_CMP_PKIBODY_IP:
599             case OSSL_CMP_PKIBODY_CP:
600             case OSSL_CMP_PKIBODY_KUP:
601             case OSSL_CMP_PKIBODY_CCP:
602                 if (ctx->trusted != NULL) {
603                     STACK_OF(X509) *certs = msg->body->value.ip->caPubs;
604                     /* value.ip is same for cp, kup, and ccp */
605 
606                     if (!ossl_cmp_X509_STORE_add1_certs(ctx->trusted, certs, 0))
607                         /* adds both self-issued and not self-issued certs */
608                         return 0;
609                 }
610                 break;
611             default:
612                 break;
613             }
614             ossl_cmp_debug(ctx,
615                            "successfully validated PBM-based CMP message protection");
616             return 1;
617         }
618         ossl_cmp_warn(ctx, "verifying PBM-based CMP message protection failed");
619         break;
620 
621         /*
622          * 5.1.3.2 DH Key Pairs
623          * Not yet supported
624          */
625     case NID_id_DHBasedMac:
626         ERR_raise(ERR_LIB_CMP, CMP_R_UNSUPPORTED_PROTECTION_ALG_DHBASEDMAC);
627         break;
628 
629         /*
630          * 5.1.3.3.  Signature
631          */
632     default:
633         scrt = ctx->srvCert;
634         if (scrt == NULL) {
635             if (ctx->trusted == NULL && ctx->secretValue != NULL) {
636                 ossl_cmp_info(ctx, "no trust store nor pinned server cert available for verifying signature-based CMP message protection");
637                 ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_TRUST_ANCHOR);
638                 return 0;
639             }
640             if (check_msg_find_cert(ctx, msg)) {
641                 ossl_cmp_debug(ctx,
642                                "successfully validated signature-based CMP message protection using trust store");
643                 return 1;
644             }
645         } else { /* use pinned sender cert */
646             /* use ctx->srvCert for signature check even if not acceptable */
647             if (verify_signature(ctx, msg, scrt)) {
648                 ossl_cmp_debug(ctx,
649                                "successfully validated signature-based CMP message protection using pinned server cert");
650                 return ossl_cmp_ctx_set1_validatedSrvCert(ctx, scrt);
651             }
652             ossl_cmp_warn(ctx, "CMP message signature verification failed");
653             ERR_raise(ERR_LIB_CMP, CMP_R_SRVCERT_DOES_NOT_VALIDATE_MSG);
654         }
655         break;
656     }
657     return 0;
658 }
659 
check_transactionID_or_nonce(ASN1_OCTET_STRING * expected,ASN1_OCTET_STRING * actual,int reason)660 static int check_transactionID_or_nonce(ASN1_OCTET_STRING *expected,
661                                         ASN1_OCTET_STRING *actual, int reason)
662 {
663     if (expected != NULL
664         && (actual == NULL || ASN1_OCTET_STRING_cmp(expected, actual) != 0)) {
665 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
666         char *expected_str, *actual_str;
667 
668         expected_str = i2s_ASN1_OCTET_STRING(NULL, expected);
669         actual_str = actual == NULL ? NULL: i2s_ASN1_OCTET_STRING(NULL, actual);
670         ERR_raise_data(ERR_LIB_CMP, reason,
671                        "expected = %s, actual = %s",
672                        expected_str == NULL ? "?" : expected_str,
673                        actual == NULL ? "(none)" :
674                        actual_str == NULL ? "?" : actual_str);
675         OPENSSL_free(expected_str);
676         OPENSSL_free(actual_str);
677         return 0;
678 #endif
679     }
680     return 1;
681 }
682 
683 /*-
684  * Check received message (i.e., response by server or request from client)
685  * Any msg->extraCerts are prepended to ctx->untrusted.
686  *
687  * Ensures that:
688  * its sender is of appropriate type (currently only X509_NAME) and
689  *     matches any expected sender or srvCert subject given in the ctx
690  * it has a valid body type
691  * its protection is valid (or invalid/absent, but only if a callback function
692  *     is present and yields a positive result using also the supplied argument)
693  * its transaction ID matches the previous transaction ID stored in ctx (if any)
694  * its recipNonce matches the previous senderNonce stored in the ctx (if any)
695  *
696  * If everything is fine:
697  * learns the senderNonce from the received message,
698  * learns the transaction ID if it is not yet in ctx,
699  * and makes any certs in caPubs directly trusted.
700  *
701  * Returns 1 on success, 0 on error.
702  */
ossl_cmp_msg_check_update(OSSL_CMP_CTX * ctx,const OSSL_CMP_MSG * msg,ossl_cmp_allow_unprotected_cb_t cb,int cb_arg)703 int ossl_cmp_msg_check_update(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg,
704                               ossl_cmp_allow_unprotected_cb_t cb, int cb_arg)
705 {
706     OSSL_CMP_PKIHEADER *hdr;
707     const X509_NAME *expected_sender;
708     int num_untrusted, num_added, res;
709 
710     if (!ossl_assert(ctx != NULL && msg != NULL && msg->header != NULL))
711         return 0;
712     hdr = OSSL_CMP_MSG_get0_header(msg);
713 
714     /* If expected_sender is given, validate sender name of received msg */
715     expected_sender = ctx->expected_sender;
716     if (expected_sender == NULL && ctx->srvCert != NULL)
717         expected_sender = X509_get_subject_name(ctx->srvCert);
718     if (expected_sender != NULL) {
719         const X509_NAME *actual_sender;
720         char *str;
721 
722         if (hdr->sender->type != GEN_DIRNAME) {
723             ERR_raise(ERR_LIB_CMP, CMP_R_SENDER_GENERALNAME_TYPE_NOT_SUPPORTED);
724             return 0;
725         }
726         actual_sender = hdr->sender->d.directoryName;
727         /*
728          * Compare actual sender name of response with expected sender name.
729          * Mitigates risk of accepting misused PBM secret or
730          * misused certificate of an unauthorized entity of a trusted hierarchy.
731          */
732         if (!check_name(ctx, 0, "sender DN field", actual_sender,
733                         "expected sender", expected_sender)) {
734             str = X509_NAME_oneline(actual_sender, NULL, 0);
735             ERR_raise_data(ERR_LIB_CMP, CMP_R_UNEXPECTED_SENDER,
736                            str != NULL ? str : "<unknown>");
737             OPENSSL_free(str);
738             return 0;
739         }
740     }
741     /* Note: if recipient was NULL-DN it could be learned here if needed */
742 
743     num_added = sk_X509_num(msg->extraCerts);
744     if (num_added > 10)
745         ossl_cmp_log1(WARN, ctx, "received CMP message contains %d extraCerts",
746                       num_added);
747     /*
748      * Store any provided extraCerts in ctx for use in OSSL_CMP_validate_msg()
749      * and for future use, such that they are available to ctx->certConf_cb and
750      * the peer does not need to send them again in the same transaction.
751      * Note that it does not help validating the message before storing the
752      * extraCerts because they do not belong to the protected msg part anyway.
753      * The extraCerts are prepended. Allows simple removal if they shall not be
754      * cached. Also they get used first, which is likely good for efficiency.
755      */
756     num_untrusted = ctx->untrusted == NULL ? 0 : sk_X509_num(ctx->untrusted);
757     res = ossl_x509_add_certs_new(&ctx->untrusted, msg->extraCerts,
758                                   /* this allows self-signed certs */
759                                   X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP
760                                   | X509_ADD_FLAG_PREPEND);
761     num_added = (ctx->untrusted == NULL ? 0 : sk_X509_num(ctx->untrusted))
762         - num_untrusted;
763     if (!res) {
764         while (num_added-- > 0)
765             X509_free(sk_X509_shift(ctx->untrusted));
766         return 0;
767     }
768 
769     if (hdr->protectionAlg != NULL)
770         res = OSSL_CMP_validate_msg(ctx, msg)
771             /* explicitly permitted exceptions for invalid protection: */
772             || (cb != NULL && (*cb)(ctx, msg, 1, cb_arg) > 0);
773     else
774         /* explicitly permitted exceptions for missing protection: */
775         res = cb != NULL && (*cb)(ctx, msg, 0, cb_arg) > 0;
776 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
777     res = 1; /* support more aggressive fuzzing by letting invalid msg pass */
778 #endif
779 
780     /* remove extraCerts again if not caching */
781     if (ctx->noCacheExtraCerts)
782         while (num_added-- > 0)
783             X509_free(sk_X509_shift(ctx->untrusted));
784 
785     if (!res) {
786         if (hdr->protectionAlg != NULL)
787             ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_VALIDATING_PROTECTION);
788         else
789             ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_PROTECTION);
790         return 0;
791     }
792 
793     /* check CMP version number in header */
794     if (ossl_cmp_hdr_get_pvno(hdr) != OSSL_CMP_PVNO_2
795             && ossl_cmp_hdr_get_pvno(hdr) != OSSL_CMP_PVNO_3) {
796 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
797         ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PVNO);
798         return 0;
799 #endif
800     }
801 
802     if (OSSL_CMP_MSG_get_bodytype(msg) < 0) {
803 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
804         ERR_raise(ERR_LIB_CMP, CMP_R_PKIBODY_ERROR);
805         return 0;
806 #endif
807     }
808 
809     /* compare received transactionID with the expected one in previous msg */
810     if (!check_transactionID_or_nonce(ctx->transactionID, hdr->transactionID,
811                                       CMP_R_TRANSACTIONID_UNMATCHED))
812         return 0;
813 
814     /*
815      * enable clearing irrelevant errors
816      * in attempts to validate recipient nonce in case of delayed delivery.
817      */
818     (void)ERR_set_mark();
819     /* compare received nonce with the one we sent */
820     if (!check_transactionID_or_nonce(ctx->senderNonce, hdr->recipNonce,
821                                       CMP_R_RECIPNONCE_UNMATCHED)) {
822         /* check if we are polling and received final response */
823         if (ctx->first_senderNonce == NULL
824             || OSSL_CMP_MSG_get_bodytype(msg) == OSSL_CMP_PKIBODY_POLLREP
825             /* compare received nonce with our sender nonce at poll start */
826             || !check_transactionID_or_nonce(ctx->first_senderNonce,
827                                              hdr->recipNonce,
828                                              CMP_R_RECIPNONCE_UNMATCHED)) {
829             (void)ERR_clear_last_mark();
830             return 0;
831         }
832     }
833     (void)ERR_pop_to_mark();
834 
835     /* if not yet present, learn transactionID */
836     if (ctx->transactionID == NULL
837         && !OSSL_CMP_CTX_set1_transactionID(ctx, hdr->transactionID))
838         return 0;
839 
840     /*
841      * RFC 4210 section 5.1.1 states: the recipNonce is copied from
842      * the senderNonce of the previous message in the transaction.
843      * --> Store for setting in next message
844      */
845     if (!ossl_cmp_ctx_set1_recipNonce(ctx, hdr->senderNonce))
846         return 0;
847 
848     if (ossl_cmp_hdr_get_protection_nid(hdr) == NID_id_PasswordBasedMAC) {
849         /*
850          * RFC 4210, 5.3.2: 'Note that if the PKI Message Protection is
851          * "shared secret information", then any certificate transported in
852          * the caPubs field may be directly trusted as a root CA
853          * certificate by the initiator.'
854          */
855         switch (OSSL_CMP_MSG_get_bodytype(msg)) {
856         case OSSL_CMP_PKIBODY_IP:
857         case OSSL_CMP_PKIBODY_CP:
858         case OSSL_CMP_PKIBODY_KUP:
859         case OSSL_CMP_PKIBODY_CCP:
860             if (ctx->trusted != NULL) {
861                 STACK_OF(X509) *certs = msg->body->value.ip->caPubs;
862                 /* value.ip is same for cp, kup, and ccp */
863 
864                 if (!ossl_cmp_X509_STORE_add1_certs(ctx->trusted, certs, 0))
865                     /* adds both self-issued and not self-issued certs */
866                     return 0;
867             }
868             break;
869         default:
870             break;
871         }
872     }
873     return 1;
874 }
875 
ossl_cmp_verify_popo(const OSSL_CMP_CTX * ctx,const OSSL_CMP_MSG * msg,int acceptRAVerified)876 int ossl_cmp_verify_popo(const OSSL_CMP_CTX *ctx,
877                          const OSSL_CMP_MSG *msg, int acceptRAVerified)
878 {
879     if (!ossl_assert(msg != NULL && msg->body != NULL))
880         return 0;
881     switch (msg->body->type) {
882     case OSSL_CMP_PKIBODY_P10CR:
883         {
884             X509_REQ *req = msg->body->value.p10cr;
885 
886             if (X509_REQ_verify_ex(req, X509_REQ_get0_pubkey(req), ctx->libctx,
887                                    ctx->propq) <= 0) {
888 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
889                 ERR_raise(ERR_LIB_CMP, CMP_R_REQUEST_NOT_ACCEPTED);
890                 return 0;
891 #endif
892             }
893         }
894         break;
895     case OSSL_CMP_PKIBODY_IR:
896     case OSSL_CMP_PKIBODY_CR:
897     case OSSL_CMP_PKIBODY_KUR:
898         if (!OSSL_CRMF_MSGS_verify_popo(msg->body->value.ir, OSSL_CMP_CERTREQID,
899                                         acceptRAVerified,
900                                         ctx->libctx, ctx->propq)) {
901 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
902             return 0;
903 #endif
904         }
905         break;
906     default:
907         ERR_raise(ERR_LIB_CMP, CMP_R_PKIBODY_ERROR);
908         return 0;
909     }
910     return 1;
911 }
912