/** * FreeRDP: A Remote Desktop Protocol Implementation * Cryptographic Abstraction Layer * * Copyright 2011-2012 Marc-Andre Moreau * * 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. */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include #include #include #define TAG FREERDP_TAG("crypto") CryptoCert crypto_cert_read(BYTE* data, UINT32 length) { CryptoCert cert = malloc(sizeof(*cert)); if (!cert) return NULL; /* this will move the data pointer but we don't care, we don't use it again */ cert->px509 = d2i_X509(NULL, (D2I_X509_CONST BYTE**)&data, length); return cert; } void crypto_cert_free(CryptoCert cert) { if (cert == NULL) return; X509_free(cert->px509); free(cert); } BOOL crypto_cert_get_public_key(CryptoCert cert, BYTE** PublicKey, DWORD* PublicKeyLength) { BYTE* ptr; int length; BOOL status = TRUE; EVP_PKEY* pkey = NULL; pkey = X509_get_pubkey(cert->px509); if (!pkey) { WLog_ERR(TAG, "X509_get_pubkey() failed"); status = FALSE; goto exit; } length = i2d_PublicKey(pkey, NULL); if (length < 1) { WLog_ERR(TAG, "i2d_PublicKey() failed"); status = FALSE; goto exit; } *PublicKeyLength = (DWORD)length; *PublicKey = (BYTE*)malloc(length); ptr = (BYTE*)(*PublicKey); if (!ptr) { status = FALSE; goto exit; } i2d_PublicKey(pkey, &ptr); exit: if (pkey) EVP_PKEY_free(pkey); return status; } static int crypto_rsa_common(const BYTE* input, int length, UINT32 key_length, const BYTE* modulus, const BYTE* exponent, int exponent_size, BYTE* output) { BN_CTX* ctx = NULL; int output_length = -1; BYTE* input_reverse = NULL; BYTE* modulus_reverse = NULL; BYTE* exponent_reverse = NULL; BIGNUM* mod = NULL; BIGNUM* exp = NULL; BIGNUM* x = NULL; BIGNUM* y = NULL; size_t bufferSize = 2 * key_length + exponent_size; if (!input || (length < 0) || (exponent_size < 0) || !modulus || !exponent || !output) return -1; if (length > bufferSize) bufferSize = length; input_reverse = (BYTE*)calloc(bufferSize, 1); if (!input_reverse) return -1; modulus_reverse = input_reverse + key_length; exponent_reverse = modulus_reverse + key_length; memcpy(modulus_reverse, modulus, key_length); crypto_reverse(modulus_reverse, key_length); memcpy(exponent_reverse, exponent, exponent_size); crypto_reverse(exponent_reverse, exponent_size); memcpy(input_reverse, input, length); crypto_reverse(input_reverse, length); if (!(ctx = BN_CTX_new())) goto fail_bn_ctx; if (!(mod = BN_new())) goto fail_bn_mod; if (!(exp = BN_new())) goto fail_bn_exp; if (!(x = BN_new())) goto fail_bn_x; if (!(y = BN_new())) goto fail_bn_y; if (!BN_bin2bn(modulus_reverse, key_length, mod)) goto fail; if (!BN_bin2bn(exponent_reverse, exponent_size, exp)) goto fail; if (!BN_bin2bn(input_reverse, length, x)) goto fail; if (BN_mod_exp(y, x, exp, mod, ctx) != 1) goto fail; output_length = BN_bn2bin(y, output); if (output_length < 0) goto fail; crypto_reverse(output, output_length); if (output_length < key_length) memset(output + output_length, 0, key_length - output_length); fail: BN_free(y); fail_bn_y: BN_clear_free(x); fail_bn_x: BN_free(exp); fail_bn_exp: BN_free(mod); fail_bn_mod: BN_CTX_free(ctx); fail_bn_ctx: free(input_reverse); return output_length; } static int crypto_rsa_public(const BYTE* input, int length, UINT32 key_length, const BYTE* modulus, const BYTE* exponent, BYTE* output) { return crypto_rsa_common(input, length, key_length, modulus, exponent, EXPONENT_MAX_SIZE, output); } static int crypto_rsa_private(const BYTE* input, int length, UINT32 key_length, const BYTE* modulus, const BYTE* private_exponent, BYTE* output) { return crypto_rsa_common(input, length, key_length, modulus, private_exponent, key_length, output); } int crypto_rsa_public_encrypt(const BYTE* input, int length, UINT32 key_length, const BYTE* modulus, const BYTE* exponent, BYTE* output) { return crypto_rsa_public(input, length, key_length, modulus, exponent, output); } int crypto_rsa_public_decrypt(const BYTE* input, int length, UINT32 key_length, const BYTE* modulus, const BYTE* exponent, BYTE* output) { return crypto_rsa_public(input, length, key_length, modulus, exponent, output); } int crypto_rsa_private_encrypt(const BYTE* input, int length, UINT32 key_length, const BYTE* modulus, const BYTE* private_exponent, BYTE* output) { return crypto_rsa_private(input, length, key_length, modulus, private_exponent, output); } int crypto_rsa_private_decrypt(const BYTE* input, int length, UINT32 key_length, const BYTE* modulus, const BYTE* private_exponent, BYTE* output) { return crypto_rsa_private(input, length, key_length, modulus, private_exponent, output); } static int crypto_rsa_decrypt(const BYTE* input, int length, UINT32 key_length, const BYTE* modulus, const BYTE* private_exponent, BYTE* output) { return crypto_rsa_common(input, length, key_length, modulus, private_exponent, key_length, output); } void crypto_reverse(BYTE* data, int length) { int i, j; BYTE temp; for (i = 0, j = length - 1; i < j; i++, j--) { temp = data[i]; data[i] = data[j]; data[j] = temp; } } char* crypto_cert_fingerprint(X509* xcert) { return crypto_cert_fingerprint_by_hash(xcert, "sha256"); } BYTE* crypto_cert_hash(X509* xcert, const char* hash, UINT32* length) { UINT32 fp_len = EVP_MAX_MD_SIZE; BYTE* fp; const EVP_MD* md = EVP_get_digestbyname(hash); if (!md) return NULL; if (!length) return NULL; if (!xcert) return NULL; fp = calloc(fp_len, sizeof(BYTE)); if (!fp) return NULL; if (X509_digest(xcert, md, fp, &fp_len) != 1) { free(fp); return NULL; } *length = fp_len; return fp; } char* crypto_cert_fingerprint_by_hash(X509* xcert, const char* hash) { UINT32 fp_len, i; BYTE* fp; char* p; char* fp_buffer; fp = crypto_cert_hash(xcert, hash, &fp_len); if (!fp) return NULL; fp_buffer = calloc(fp_len * 3 + 1, sizeof(char)); if (!fp_buffer) goto fail; p = fp_buffer; for (i = 0; i < (fp_len - 1); i++) { sprintf_s(p, (fp_len - i) * 3, "%02" PRIx8 ":", fp[i]); p = &fp_buffer[(i + 1) * 3]; } sprintf_s(p, (fp_len - i) * 3, "%02" PRIx8 "", fp[i]); fail: free(fp); return fp_buffer; } static char* crypto_print_name(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) { unsigned long size = BIO_number_written(outBIO); buffer = calloc(1, size + 1); if (!buffer) return NULL; BIO_read(outBIO, buffer, size); } BIO_free_all(outBIO); return buffer; } char* crypto_cert_subject(X509* xcert) { return crypto_print_name(X509_get_subject_name(xcert)); } char* crypto_cert_subject_common_name(X509* xcert, int* length) { int index; BYTE* common_name_raw; char* common_name; X509_NAME* subject_name; X509_NAME_ENTRY* entry; ASN1_STRING* entry_data; subject_name = X509_get_subject_name(xcert); if (subject_name == NULL) return NULL; index = X509_NAME_get_index_by_NID(subject_name, NID_commonName, -1); if (index < 0) return NULL; entry = X509_NAME_get_entry(subject_name, index); if (entry == NULL) return NULL; entry_data = X509_NAME_ENTRY_get_data(entry); if (entry_data == NULL) return NULL; *length = ASN1_STRING_to_UTF8(&common_name_raw, entry_data); if (*length < 0) return NULL; common_name = _strdup((char*)common_name_raw); OPENSSL_free(common_name_raw); return (char*)common_name; } /* 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]; sprintf(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(X509* x509, int general_name_type, general_name_mapper_pr mapper, void* data) { int i; int num; STACK_OF(GENERAL_NAME) * gens; gens = X509_get_ext_d2i(x509, NID_subject_alt_name, NULL, NULL); if (!gens) { return; } num = sk_GENERAL_NAME_num(gens); for (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; 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; unsigned char* utf8String; int length; /* 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 = (char*)_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; } /* crypto_cert_get_email returns a dynamically allocated copy of the first email found in the subjectAltNames (use free to free it). */ char* crypto_cert_get_email(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; } /* crypto_cert_get_upn returns a dynamically allocated copy of the first UPN otherNames in the subjectAltNames (use free to free it). Note: if this first UPN otherName is not a string, then 0 is returned, instead of searching for another UPN that would be a string. */ char* crypto_cert_get_upn(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; } /* Deprecated name.*/ void crypto_cert_subject_alt_name_free(int count, int* lengths, char** alt_names) { crypto_cert_dns_names_free(count, lengths, alt_names); } void crypto_cert_dns_names_free(int count, int* lengths, char** dns_names) { free(lengths); if (dns_names) { int i; for (i = 0; i < count; i++) { if (dns_names[i]) { OPENSSL_free(dns_names[i]); } } free(dns_names); } } /* Deprecated name.*/ char** crypto_cert_subject_alt_name(X509* xcert, int* count, int** lengths) { return crypto_cert_get_dns_names(xcert, count, lengths); } char** crypto_cert_get_dns_names(X509* x509, int* count, int** lengths) { int i; 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 (i = 0; i < list.count; i++) { result[i] = list.strings[i]; (*lengths)[i] = strlen(result[i]); } string_list_free(&list); return result; } char* crypto_cert_issuer(X509* xcert) { return crypto_print_name(X509_get_issuer_name(xcert)); } static int verify_cb(int ok, X509_STORE_CTX* csc) { if (ok != 1) { 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 = crypto_cert_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_verify_certificate(CryptoCert cert, const char* certificate_store_path) { size_t i; const int purposes[3] = { X509_PURPOSE_SSL_SERVER, X509_PURPOSE_SSL_CLIENT, X509_PURPOSE_ANY }; X509_STORE_CTX* csc; BOOL status = FALSE; X509_STORE* cert_ctx = NULL; X509_LOOKUP* lookup = NULL; 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 lookup = X509_STORE_add_lookup(cert_ctx, X509_LOOKUP_file()); if (lookup == NULL) 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 (i = 0; i < ARRAYSIZE(purposes); i++) { int err = -1, rc = -1; int purpose = purposes[i]; csc = X509_STORE_CTX_new(); if (csc == NULL) goto skip; if (!X509_STORE_CTX_init(csc, cert_ctx, cert->px509, cert->px509chain)) 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; } rdpCertificateData* crypto_get_certificate_data(X509* xcert, const char* hostname, UINT16 port) { char* issuer; char* subject; char* fp; rdpCertificateData* certdata; fp = crypto_cert_fingerprint(xcert); if (!fp) return NULL; issuer = crypto_cert_issuer(xcert); subject = crypto_cert_subject(xcert); certdata = certificate_data_new(hostname, port, issuer, subject, fp); free(subject); free(issuer); free(fp); return certdata; } void crypto_cert_print_info(X509* xcert) { char* fp; char* issuer; char* subject; subject = crypto_cert_subject(xcert); issuer = crypto_cert_issuer(xcert); fp = crypto_cert_fingerprint(xcert); 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); }