/** * FreeRDP: A Remote Desktop Protocol Implementation * Cryptographic Abstraction Layer * * Copyright 2011-2012 Marc-Andre Moreau * Copyright 2023 Armin Novak * Copyright 2023 Thincast Technologies GmbH * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include #include #include #include #include #include #include #include #include #include "x509_utils.h" #define TAG FREERDP_TAG("crypto") BYTE* x509_utils_get_hash(const X509* xcert, const char* hash, size_t* length) { UINT32 fp_len = EVP_MAX_MD_SIZE; BYTE* fp = NULL; const EVP_MD* md = EVP_get_digestbyname(hash); if (!md) { WLog_ERR(TAG, "System does not support %s hash!", hash); return NULL; } if (!xcert || !length) { WLog_ERR(TAG, "Invalid arugments: xcert=%p, length=%p", xcert, length); return NULL; } fp = calloc(fp_len + 1, sizeof(BYTE)); if (!fp) { WLog_ERR(TAG, "could not allocate %" PRIuz " bytes", fp_len); return NULL; } if (X509_digest(xcert, md, fp, &fp_len) != 1) { free(fp); WLog_ERR(TAG, "certificate does not have a %s hash!", hash); return NULL; } *length = fp_len; return fp; } static char* crypto_print_name(const X509_NAME* name) { char* buffer = NULL; BIO* outBIO = BIO_new(BIO_s_mem()); if (X509_NAME_print_ex(outBIO, name, 0, XN_FLAG_ONELINE) > 0) { UINT64 size = BIO_number_written(outBIO); if (size > INT_MAX) goto fail; buffer = calloc(1, (size_t)size + 1); if (!buffer) goto fail; ERR_clear_error(); const int rc = BIO_read(outBIO, buffer, (int)size); if (rc <= 0) { free(buffer); buffer = NULL; goto fail; } } fail: BIO_free_all(outBIO); return buffer; } char* x509_utils_get_subject(const X509* xcert) { char* subject = NULL; if (!xcert) { WLog_ERR(TAG, "Invalid certificate %p", xcert); return NULL; } subject = crypto_print_name(X509_get_subject_name(xcert)); if (!subject) WLog_WARN(TAG, "certificate does not have a subject!"); return subject; } /* GENERAL_NAME type labels */ static const char* general_name_type_labels[] = { "OTHERNAME", "EMAIL ", "DNS ", "X400 ", "DIRNAME ", "EDIPARTY ", "URI ", "IPADD ", "RID " }; static const char* general_name_type_label(int general_name_type) { if ((0 <= general_name_type) && ((size_t)general_name_type < ARRAYSIZE(general_name_type_labels))) { return general_name_type_labels[general_name_type]; } else { static char buffer[80] = { 0 }; (void)snprintf(buffer, sizeof(buffer), "Unknown general name type (%d)", general_name_type); return buffer; } } /* map_subject_alt_name(x509, general_name_type, mapper, data) Call the function mapper with subjectAltNames found in the x509 certificate and data. if generate_name_type is GEN_ALL, the the mapper is called for all the names, else it's called only for names of the given type. We implement two extractors: - a string extractor that can be used to get the subjectAltNames of the following types: GEN_URI, GEN_DNS, GEN_EMAIL - a ASN1_OBJECT filter/extractor that can be used to get the subjectAltNames of OTHERNAME type. Note: usually, it's a string, but some type of otherNames can be associated with different classes of objects. eg. a KPN may be a sequence of realm and principal name, instead of a single string object. Not implemented yet: extractors for the types: GEN_X400, GEN_DIRNAME, GEN_EDIPARTY, GEN_RID, GEN_IPADD (the later can contain nul-bytes). mapper(name, data, index, count) The mapper is passed: - the GENERAL_NAME selected, - the data, - the index of the general name in the subjectAltNames, - the total number of names in the subjectAltNames. The last parameter let's the mapper allocate arrays to collect objects. Note: if names are filtered, not all the indices from 0 to count-1 are passed to mapper, only the indices selected. When the mapper returns 0, map_subject_alt_name stops the iteration immediately. */ #define GEN_ALL (-1) typedef int (*general_name_mapper_pr)(GENERAL_NAME* name, void* data, int index, int count); static void map_subject_alt_name(const X509* x509, int general_name_type, general_name_mapper_pr mapper, void* data) { int num = 0; STACK_OF(GENERAL_NAME)* gens = NULL; gens = X509_get_ext_d2i(x509, NID_subject_alt_name, NULL, NULL); if (!gens) { return; } num = sk_GENERAL_NAME_num(gens); for (int i = 0; (i < num); i++) { GENERAL_NAME* name = sk_GENERAL_NAME_value(gens, i); if (name) { if ((general_name_type == GEN_ALL) || (general_name_type == name->type)) { if (!mapper(name, data, i, num)) { break; } } } } sk_GENERAL_NAME_pop_free(gens, GENERAL_NAME_free); } /* extract_string -- string extractor - the strings array is allocated lazily, when we first have to store a string. - allocated contains the size of the strings array, or -1 if allocation failed. - count contains the actual count of strings in the strings array. - maximum limits the number of strings we can store in the strings array: beyond, the extractor returns 0 to short-cut the search. extract_string stores in the string list OPENSSL strings, that must be freed with OPENSSL_free. */ typedef struct string_list { char** strings; int allocated; int count; int maximum; } string_list; static void string_list_initialize(string_list* list) { list->strings = 0; list->allocated = 0; list->count = 0; list->maximum = INT_MAX; } static void string_list_allocate(string_list* list, int allocate_count) { if (!list->strings && list->allocated == 0) { list->strings = calloc((size_t)allocate_count, sizeof(char*)); list->allocated = list->strings ? allocate_count : -1; list->count = 0; } } static void string_list_free(string_list* list) { /* Note: we don't free the contents of the strings array: this */ /* is handled by the caller, either by returning this */ /* content, or freeing it itself. */ free(list->strings); } static int extract_string(GENERAL_NAME* name, void* data, int index, int count) { string_list* list = data; unsigned char* cstring = 0; ASN1_STRING* str = NULL; switch (name->type) { case GEN_URI: str = name->d.uniformResourceIdentifier; break; case GEN_DNS: str = name->d.dNSName; break; case GEN_EMAIL: str = name->d.rfc822Name; break; default: return 1; } if ((ASN1_STRING_to_UTF8(&cstring, str)) < 0) { WLog_ERR(TAG, "ASN1_STRING_to_UTF8() failed for %s: %s", general_name_type_label(name->type), ERR_error_string(ERR_get_error(), NULL)); return 1; } string_list_allocate(list, count); if (list->allocated <= 0) { OPENSSL_free(cstring); return 0; } list->strings[list->count] = (char*)cstring; list->count++; if (list->count >= list->maximum) { return 0; } return 1; } /* extract_othername_object -- object extractor. - the objects array is allocated lazily, when we first have to store a string. - allocated contains the size of the objects array, or -1 if allocation failed. - count contains the actual count of objects in the objects array. - maximum limits the number of objects we can store in the objects array: beyond, the extractor returns 0 to short-cut the search. extract_othername_objects stores in the objects array ASN1_TYPE * pointers directly obtained from the GENERAL_NAME. */ typedef struct object_list { ASN1_OBJECT* type_id; char** strings; int allocated; int count; int maximum; } object_list; static void object_list_initialize(object_list* list) { list->type_id = 0; list->strings = 0; list->allocated = 0; list->count = 0; list->maximum = INT_MAX; } static void object_list_allocate(object_list* list, int allocate_count) { if (!list->strings && list->allocated == 0) { list->strings = calloc(allocate_count, sizeof(list->strings[0])); list->allocated = list->strings ? allocate_count : -1; list->count = 0; } } static char* object_string(ASN1_TYPE* object) { char* result = NULL; unsigned char* utf8String = NULL; int length = 0; /* TODO: check that object.type is a string type. */ length = ASN1_STRING_to_UTF8(&utf8String, object->value.asn1_string); if (length < 0) { return 0; } result = _strdup((char*)utf8String); OPENSSL_free(utf8String); return result; } static void object_list_free(object_list* list) { free(list->strings); } static int extract_othername_object_as_string(GENERAL_NAME* name, void* data, int index, int count) { object_list* list = data; if (name->type != GEN_OTHERNAME) { return 1; } if (0 != OBJ_cmp(name->d.otherName->type_id, list->type_id)) { return 1; } object_list_allocate(list, count); if (list->allocated <= 0) { return 0; } list->strings[list->count] = object_string(name->d.otherName->value); if (list->strings[list->count]) { list->count++; } if (list->count >= list->maximum) { return 0; } return 1; } char* x509_utils_get_email(const X509* x509) { char* result = 0; string_list list; string_list_initialize(&list); list.maximum = 1; map_subject_alt_name(x509, GEN_EMAIL, extract_string, &list); if (list.count == 0) { string_list_free(&list); return 0; } result = _strdup(list.strings[0]); OPENSSL_free(list.strings[0]); string_list_free(&list); return result; } char* x509_utils_get_upn(const X509* x509) { char* result = 0; object_list list; object_list_initialize(&list); list.type_id = OBJ_nid2obj(NID_ms_upn); list.maximum = 1; map_subject_alt_name(x509, GEN_OTHERNAME, extract_othername_object_as_string, &list); if (list.count == 0) { object_list_free(&list); return 0; } result = list.strings[0]; object_list_free(&list); return result; } char* x509_utils_get_date(const X509* x509, BOOL startDate) { WINPR_ASSERT(x509); const ASN1_TIME* date = startDate ? X509_get0_notBefore(x509) : X509_get0_notAfter(x509); if (!date) return NULL; BIO* bmem = BIO_new(BIO_s_mem()); if (!bmem) return NULL; char* str = NULL; if (ASN1_TIME_print(bmem, date)) { BUF_MEM* bptr = NULL; BIO_get_mem_ptr(bmem, &bptr); str = strndup(bptr->data, bptr->length); } else { // Log error } BIO_free_all(bmem); return str; } void x509_utils_dns_names_free(size_t count, size_t* lengths, char** dns_names) { free(lengths); if (dns_names) { for (size_t i = 0; i < count; i++) { if (dns_names[i]) { OPENSSL_free(dns_names[i]); } } free(dns_names); } } char** x509_utils_get_dns_names(const X509* x509, size_t* count, size_t** lengths) { char** result = 0; string_list list; string_list_initialize(&list); map_subject_alt_name(x509, GEN_DNS, extract_string, &list); (*count) = list.count; if (list.count == 0) { string_list_free(&list); return NULL; } /* lengths are not useful, since we converted the strings to utf-8, there cannot be nul-bytes in them. */ result = calloc(list.count, sizeof(*result)); (*lengths) = calloc(list.count, sizeof(**lengths)); if (!result || !(*lengths)) { string_list_free(&list); free(result); free(*lengths); (*lengths) = 0; (*count) = 0; return NULL; } for (int i = 0; i < list.count; i++) { result[i] = list.strings[i]; (*lengths)[i] = strlen(result[i]); } string_list_free(&list); return result; } char* x509_utils_get_issuer(const X509* xcert) { char* issuer = NULL; if (!xcert) { WLog_ERR(TAG, "Invalid certificate %p", xcert); return NULL; } issuer = crypto_print_name(X509_get_issuer_name(xcert)); if (!issuer) WLog_WARN(TAG, "certificate does not have an issuer!"); return issuer; } BOOL x509_utils_check_eku(const X509* xcert, int nid) { BOOL ret = FALSE; STACK_OF(ASN1_OBJECT)* oid_stack = NULL; ASN1_OBJECT* oid = NULL; if (!xcert) return FALSE; oid = OBJ_nid2obj(nid); if (!oid) return FALSE; oid_stack = X509_get_ext_d2i(xcert, NID_ext_key_usage, NULL, NULL); if (!oid_stack) return FALSE; if (sk_ASN1_OBJECT_find(oid_stack, oid) >= 0) ret = TRUE; sk_ASN1_OBJECT_pop_free(oid_stack, ASN1_OBJECT_free); return ret; } void x509_utils_print_info(const X509* xcert) { char* fp = NULL; char* issuer = NULL; char* subject = NULL; subject = x509_utils_get_subject(xcert); issuer = x509_utils_get_issuer(xcert); fp = (char*)x509_utils_get_hash(xcert, "sha256", NULL); if (!fp) { WLog_ERR(TAG, "error computing fingerprint"); goto out_free_issuer; } WLog_INFO(TAG, "Certificate details:"); WLog_INFO(TAG, "\tSubject: %s", subject); WLog_INFO(TAG, "\tIssuer: %s", issuer); WLog_INFO(TAG, "\tThumbprint: %s", fp); WLog_INFO(TAG, "The above X.509 certificate could not be verified, possibly because you do not have " "the CA certificate in your certificate store, or the certificate has expired. " "Please look at the OpenSSL documentation on how to add a private CA to the store."); free(fp); out_free_issuer: free(issuer); free(subject); } X509* x509_utils_from_pem(const char* data, size_t len, BOOL fromFile) { X509* x509 = NULL; BIO* bio = NULL; if (fromFile) bio = BIO_new_file(data, "rb"); else { if (len > INT_MAX) return NULL; bio = BIO_new_mem_buf(data, (int)len); } if (!bio) { WLog_ERR(TAG, "BIO_new failed for certificate"); return NULL; } x509 = PEM_read_bio_X509(bio, NULL, NULL, 0); BIO_free_all(bio); if (!x509) WLog_ERR(TAG, "PEM_read_bio_X509 returned NULL [input length %" PRIuz "]", len); return x509; } static WINPR_MD_TYPE hash_nid_to_winpr(int hash_nid) { switch (hash_nid) { case NID_md2: return WINPR_MD_MD2; case NID_md4: return WINPR_MD_MD4; case NID_md5: return WINPR_MD_MD5; case NID_sha1: return WINPR_MD_SHA1; case NID_sha224: return WINPR_MD_SHA224; case NID_sha256: return WINPR_MD_SHA256; case NID_sha384: return WINPR_MD_SHA384; case NID_sha512: return WINPR_MD_SHA512; case NID_ripemd160: return WINPR_MD_RIPEMD160; #if (OPENSSL_VERSION_NUMBER >= 0x1010101fL) && !defined(LIBRESSL_VERSION_NUMBER) case NID_sha3_224: return WINPR_MD_SHA3_224; case NID_sha3_256: return WINPR_MD_SHA3_256; case NID_sha3_384: return WINPR_MD_SHA3_384; case NID_sha3_512: return WINPR_MD_SHA3_512; case NID_shake128: return WINPR_MD_SHAKE128; case NID_shake256: return WINPR_MD_SHAKE256; #endif case NID_undef: default: return WINPR_MD_NONE; } } static WINPR_MD_TYPE get_rsa_pss_digest(const X509_ALGOR* alg) { WINPR_MD_TYPE ret = WINPR_MD_NONE; WINPR_MD_TYPE message_digest = WINPR_MD_NONE; WINPR_MD_TYPE mgf1_digest = WINPR_MD_NONE; int param_type = 0; const void* param_value = NULL; const ASN1_STRING* sequence = NULL; const unsigned char* inp = NULL; RSA_PSS_PARAMS* params = NULL; X509_ALGOR* mgf1_digest_alg = NULL; /* The RSA-PSS digest is encoded in a complex structure, defined in https://www.rfc-editor.org/rfc/rfc4055.html. */ X509_ALGOR_get0(NULL, ¶m_type, ¶m_value, alg); /* param_type and param_value the parameter in ASN1_TYPE form, but split into two parameters. A SEQUENCE is has type V_ASN1_SEQUENCE, and the value is an ASN1_STRING with the encoded structure. */ if (param_type != V_ASN1_SEQUENCE) goto end; sequence = param_value; /* Decode the structure. */ inp = ASN1_STRING_get0_data(sequence); params = d2i_RSA_PSS_PARAMS(NULL, &inp, ASN1_STRING_length(sequence)); if (params == NULL) goto end; /* RSA-PSS uses two hash algorithms, a message digest and also an MGF function which is, itself, parameterized by a hash function. Both fields default to SHA-1, so we must also check for the value being NULL. */ message_digest = WINPR_MD_SHA1; if (params->hashAlgorithm != NULL) { const ASN1_OBJECT* obj = NULL; X509_ALGOR_get0(&obj, NULL, NULL, params->hashAlgorithm); message_digest = hash_nid_to_winpr(OBJ_obj2nid(obj)); if (message_digest == WINPR_MD_NONE) goto end; } mgf1_digest = WINPR_MD_SHA1; if (params->maskGenAlgorithm != NULL) { const ASN1_OBJECT* obj = NULL; int mgf_param_type = 0; const void* mgf_param_value = NULL; const ASN1_STRING* mgf_param_sequence = NULL; /* First, check this is MGF-1, the only one ever defined. */ X509_ALGOR_get0(&obj, &mgf_param_type, &mgf_param_value, params->maskGenAlgorithm); if (OBJ_obj2nid(obj) != NID_mgf1) goto end; /* MGF-1 is, itself, parameterized by a hash function, encoded as an AlgorithmIdentifier. */ if (mgf_param_type != V_ASN1_SEQUENCE) goto end; mgf_param_sequence = mgf_param_value; inp = ASN1_STRING_get0_data(mgf_param_sequence); mgf1_digest_alg = d2i_X509_ALGOR(NULL, &inp, ASN1_STRING_length(mgf_param_sequence)); if (mgf1_digest_alg == NULL) goto end; /* Finally, extract the digest. */ X509_ALGOR_get0(&obj, NULL, NULL, mgf1_digest_alg); mgf1_digest = hash_nid_to_winpr(OBJ_obj2nid(obj)); if (mgf1_digest == WINPR_MD_NONE) goto end; } /* If the two digests do not match, it is ambiguous which to return. tls-server-end-point leaves it undefined, so return none. https://www.rfc-editor.org/rfc/rfc5929.html#section-4.1 */ if (message_digest != mgf1_digest) goto end; ret = message_digest; end: RSA_PSS_PARAMS_free(params); X509_ALGOR_free(mgf1_digest_alg); return ret; } WINPR_MD_TYPE x509_utils_get_signature_alg(const X509* xcert) { WINPR_ASSERT(xcert); const int nid = X509_get_signature_nid(xcert); if (nid == NID_rsassaPss) { const X509_ALGOR* alg = NULL; X509_get0_signature(NULL, &alg, xcert); return get_rsa_pss_digest(alg); } int hash_nid = 0; if (OBJ_find_sigid_algs(nid, &hash_nid, NULL) != 1) return WINPR_MD_NONE; return hash_nid_to_winpr(hash_nid); } char* x509_utils_get_common_name(const X509* xcert, size_t* plength) { X509_NAME* subject_name = X509_get_subject_name(xcert); if (subject_name == NULL) return NULL; const int index = X509_NAME_get_index_by_NID(subject_name, NID_commonName, -1); if (index < 0) return NULL; const X509_NAME_ENTRY* entry = X509_NAME_get_entry(subject_name, index); if (entry == NULL) return NULL; const ASN1_STRING* entry_data = X509_NAME_ENTRY_get_data(entry); if (entry_data == NULL) return NULL; BYTE* common_name_raw = NULL; const int length = ASN1_STRING_to_UTF8(&common_name_raw, entry_data); if (length < 0) return NULL; if (plength) *plength = (size_t)length; char* common_name = _strdup((char*)common_name_raw); OPENSSL_free(common_name_raw); return common_name; } static int verify_cb(int ok, X509_STORE_CTX* csc) { if (ok != 1) { WINPR_ASSERT(csc); int err = X509_STORE_CTX_get_error(csc); int derr = X509_STORE_CTX_get_error_depth(csc); X509* where = X509_STORE_CTX_get_current_cert(csc); const char* what = X509_verify_cert_error_string(err); char* name = x509_utils_get_subject(where); WLog_WARN(TAG, "Certificate verification failure '%s (%d)' at stack position %d", what, err, derr); WLog_WARN(TAG, "%s", name); free(name); } return ok; } BOOL x509_utils_verify(X509* xcert, STACK_OF(X509) * chain, const char* certificate_store_path) { const int purposes[3] = { X509_PURPOSE_SSL_SERVER, X509_PURPOSE_SSL_CLIENT, X509_PURPOSE_ANY }; X509_STORE_CTX* csc = NULL; BOOL status = FALSE; X509_LOOKUP* lookup = NULL; if (!xcert) return FALSE; X509_STORE* cert_ctx = X509_STORE_new(); if (cert_ctx == NULL) goto end; #if OPENSSL_VERSION_NUMBER < 0x10100000L || defined(LIBRESSL_VERSION_NUMBER) OpenSSL_add_all_algorithms(); #else OPENSSL_init_crypto(OPENSSL_INIT_ADD_ALL_CIPHERS | OPENSSL_INIT_ADD_ALL_DIGESTS | OPENSSL_INIT_LOAD_CONFIG, NULL); #endif if (X509_STORE_set_default_paths(cert_ctx) != 1) goto end; lookup = X509_STORE_add_lookup(cert_ctx, X509_LOOKUP_hash_dir()); if (lookup == NULL) goto end; X509_LOOKUP_add_dir(lookup, NULL, X509_FILETYPE_DEFAULT); if (certificate_store_path != NULL) { X509_LOOKUP_add_dir(lookup, certificate_store_path, X509_FILETYPE_PEM); } X509_STORE_set_flags(cert_ctx, 0); for (size_t i = 0; i < ARRAYSIZE(purposes); i++) { int err = -1; int rc = -1; int purpose = purposes[i]; csc = X509_STORE_CTX_new(); if (csc == NULL) goto skip; if (!X509_STORE_CTX_init(csc, cert_ctx, xcert, chain)) goto skip; X509_STORE_CTX_set_purpose(csc, purpose); X509_STORE_CTX_set_verify_cb(csc, verify_cb); rc = X509_verify_cert(csc); err = X509_STORE_CTX_get_error(csc); skip: X509_STORE_CTX_free(csc); if (rc == 1) { status = TRUE; break; } else if (err != X509_V_ERR_INVALID_PURPOSE) break; } X509_STORE_free(cert_ctx); end: return status; }