| /* |
| * X.509 base functions for creating certificates / CSRs |
| * |
| * Copyright The Mbed TLS Contributors |
| * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later |
| */ |
| |
| #include "common.h" |
| |
| #if defined(MBEDTLS_X509_CREATE_C) |
| |
| #include "x509_internal.h" |
| #include "mbedtls/asn1write.h" |
| #include "mbedtls/error.h" |
| #include "mbedtls/oid.h" |
| |
| #include <string.h> |
| |
| #include "mbedtls/platform.h" |
| |
| #include "mbedtls/asn1.h" |
| |
| /* Structure linking OIDs for X.509 DN AttributeTypes to their |
| * string representations and default string encodings used by Mbed TLS. */ |
| typedef struct { |
| const char *name; /* String representation of AttributeType, e.g. |
| * "CN" or "emailAddress". */ |
| size_t name_len; /* Length of 'name', without trailing 0 byte. */ |
| const char *oid; /* String representation of OID of AttributeType, |
| * as per RFC 5280, Appendix A.1. encoded as per |
| * X.690 */ |
| int default_tag; /* The default character encoding used for the |
| * given attribute type, e.g. |
| * MBEDTLS_ASN1_UTF8_STRING for UTF-8. */ |
| } x509_attr_descriptor_t; |
| |
| #define ADD_STRLEN(s) s, sizeof(s) - 1 |
| |
| /* X.509 DN attributes from RFC 5280, Appendix A.1. */ |
| static const x509_attr_descriptor_t x509_attrs[] = |
| { |
| { ADD_STRLEN("CN"), |
| MBEDTLS_OID_AT_CN, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("commonName"), |
| MBEDTLS_OID_AT_CN, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("C"), |
| MBEDTLS_OID_AT_COUNTRY, MBEDTLS_ASN1_PRINTABLE_STRING }, |
| { ADD_STRLEN("countryName"), |
| MBEDTLS_OID_AT_COUNTRY, MBEDTLS_ASN1_PRINTABLE_STRING }, |
| { ADD_STRLEN("O"), |
| MBEDTLS_OID_AT_ORGANIZATION, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("organizationName"), |
| MBEDTLS_OID_AT_ORGANIZATION, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("L"), |
| MBEDTLS_OID_AT_LOCALITY, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("locality"), |
| MBEDTLS_OID_AT_LOCALITY, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("R"), |
| MBEDTLS_OID_PKCS9_EMAIL, MBEDTLS_ASN1_IA5_STRING }, |
| { ADD_STRLEN("OU"), |
| MBEDTLS_OID_AT_ORG_UNIT, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("organizationalUnitName"), |
| MBEDTLS_OID_AT_ORG_UNIT, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("ST"), |
| MBEDTLS_OID_AT_STATE, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("stateOrProvinceName"), |
| MBEDTLS_OID_AT_STATE, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("emailAddress"), |
| MBEDTLS_OID_PKCS9_EMAIL, MBEDTLS_ASN1_IA5_STRING }, |
| { ADD_STRLEN("serialNumber"), |
| MBEDTLS_OID_AT_SERIAL_NUMBER, MBEDTLS_ASN1_PRINTABLE_STRING }, |
| { ADD_STRLEN("postalAddress"), |
| MBEDTLS_OID_AT_POSTAL_ADDRESS, MBEDTLS_ASN1_PRINTABLE_STRING }, |
| { ADD_STRLEN("postalCode"), |
| MBEDTLS_OID_AT_POSTAL_CODE, MBEDTLS_ASN1_PRINTABLE_STRING }, |
| { ADD_STRLEN("dnQualifier"), |
| MBEDTLS_OID_AT_DN_QUALIFIER, MBEDTLS_ASN1_PRINTABLE_STRING }, |
| { ADD_STRLEN("title"), |
| MBEDTLS_OID_AT_TITLE, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("surName"), |
| MBEDTLS_OID_AT_SUR_NAME, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("SN"), |
| MBEDTLS_OID_AT_SUR_NAME, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("givenName"), |
| MBEDTLS_OID_AT_GIVEN_NAME, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("GN"), |
| MBEDTLS_OID_AT_GIVEN_NAME, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("initials"), |
| MBEDTLS_OID_AT_INITIALS, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("pseudonym"), |
| MBEDTLS_OID_AT_PSEUDONYM, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("generationQualifier"), |
| MBEDTLS_OID_AT_GENERATION_QUALIFIER, MBEDTLS_ASN1_UTF8_STRING }, |
| { ADD_STRLEN("domainComponent"), |
| MBEDTLS_OID_DOMAIN_COMPONENT, MBEDTLS_ASN1_IA5_STRING }, |
| { ADD_STRLEN("DC"), |
| MBEDTLS_OID_DOMAIN_COMPONENT, MBEDTLS_ASN1_IA5_STRING }, |
| { NULL, 0, NULL, MBEDTLS_ASN1_NULL } |
| }; |
| |
| static const x509_attr_descriptor_t *x509_attr_descr_from_name(const char *name, size_t name_len) |
| { |
| const x509_attr_descriptor_t *cur; |
| |
| for (cur = x509_attrs; cur->name != NULL; cur++) { |
| if (cur->name_len == name_len && |
| strncmp(cur->name, name, name_len) == 0) { |
| break; |
| } |
| } |
| |
| if (cur->name == NULL) { |
| return NULL; |
| } |
| |
| return cur; |
| } |
| |
| static int hex_to_int(char c) |
| { |
| return ('0' <= c && c <= '9') ? (c - '0') : |
| ('a' <= c && c <= 'f') ? (c - 'a' + 10) : |
| ('A' <= c && c <= 'F') ? (c - 'A' + 10) : -1; |
| } |
| |
| static int hexpair_to_int(const char *hexpair) |
| { |
| int n1 = hex_to_int(*hexpair); |
| int n2 = hex_to_int(*(hexpair + 1)); |
| |
| if (n1 != -1 && n2 != -1) { |
| return (n1 << 4) | n2; |
| } else { |
| return -1; |
| } |
| } |
| |
| static int parse_attribute_value_string(const char *s, |
| int len, |
| unsigned char *data, |
| size_t *data_len) |
| { |
| const char *c; |
| const char *end = s + len; |
| unsigned char *d = data; |
| int n; |
| |
| for (c = s; c < end; c++) { |
| if (*c == '\\') { |
| c++; |
| |
| /* Check for valid escaped characters as per RFC 4514 Section 3 */ |
| if (c + 1 < end && (n = hexpair_to_int(c)) != -1) { |
| if (n == 0) { |
| return MBEDTLS_ERR_X509_INVALID_NAME; |
| } |
| *(d++) = n; |
| c++; |
| } else if (c < end && strchr(" ,=+<>#;\"\\", *c)) { |
| *(d++) = *c; |
| } else { |
| return MBEDTLS_ERR_X509_INVALID_NAME; |
| } |
| } else { |
| *(d++) = *c; |
| } |
| |
| if (d - data == MBEDTLS_X509_MAX_DN_NAME_SIZE) { |
| return MBEDTLS_ERR_X509_INVALID_NAME; |
| } |
| } |
| *data_len = (size_t) (d - data); |
| return 0; |
| } |
| |
| /** Parse a hexstring containing a DER-encoded string. |
| * |
| * \param s A string of \p len bytes hexadecimal digits. |
| * \param len Number of bytes to read from \p s. |
| * \param data Output buffer of size \p data_size. |
| * On success, it contains the payload that's DER-encoded |
| * in the input (content without the tag and length). |
| * If the DER tag is a string tag, the payload is guaranteed |
| * not to contain null bytes. |
| * \param data_size Length of the \p data buffer. |
| * \param data_len On success, the length of the parsed string. |
| * It is guaranteed to be less than |
| * #MBEDTLS_X509_MAX_DN_NAME_SIZE. |
| * \param tag The ASN.1 tag that the payload in \p data is encoded in. |
| * |
| * \retval 0 on success. |
| * \retval #MBEDTLS_ERR_X509_INVALID_NAME if \p s does not contain |
| * a valid hexstring, |
| * or if the decoded hexstring is not valid DER, |
| * or if the payload does not fit in \p data, |
| * or if the payload is more than |
| * #MBEDTLS_X509_MAX_DN_NAME_SIZE bytes, |
| * of if \p *tag is an ASN.1 string tag and the payload |
| * contains a null byte. |
| * \retval #MBEDTLS_ERR_X509_ALLOC_FAILED on low memory. |
| */ |
| static int parse_attribute_value_hex_der_encoded(const char *s, |
| size_t len, |
| unsigned char *data, |
| size_t data_size, |
| size_t *data_len, |
| int *tag) |
| { |
| /* Step 1: preliminary length checks. */ |
| /* Each byte is encoded by exactly two hexadecimal digits. */ |
| if (len % 2 != 0) { |
| /* Odd number of hex digits */ |
| return MBEDTLS_ERR_X509_INVALID_NAME; |
| } |
| size_t const der_length = len / 2; |
| if (der_length > MBEDTLS_X509_MAX_DN_NAME_SIZE + 4) { |
| /* The payload would be more than MBEDTLS_X509_MAX_DN_NAME_SIZE |
| * (after subtracting the ASN.1 tag and length). Reject this early |
| * to avoid allocating a large intermediate buffer. */ |
| return MBEDTLS_ERR_X509_INVALID_NAME; |
| } |
| if (der_length < 1) { |
| /* Avoid empty-buffer shenanigans. A valid DER encoding is never |
| * empty. */ |
| return MBEDTLS_ERR_X509_INVALID_NAME; |
| } |
| |
| /* Step 2: Decode the hex string into an intermediate buffer. */ |
| unsigned char *der = mbedtls_calloc(1, der_length); |
| if (der == NULL) { |
| return MBEDTLS_ERR_X509_ALLOC_FAILED; |
| } |
| /* Beyond this point, der needs to be freed on exit. */ |
| for (size_t i = 0; i < der_length; i++) { |
| int c = hexpair_to_int(s + 2 * i); |
| if (c < 0) { |
| goto error; |
| } |
| der[i] = c; |
| } |
| |
| /* Step 3: decode the DER. */ |
| /* We've checked that der_length >= 1 above. */ |
| *tag = der[0]; |
| { |
| unsigned char *p = der + 1; |
| if (mbedtls_asn1_get_len(&p, der + der_length, data_len) != 0) { |
| goto error; |
| } |
| /* Now p points to the first byte of the payload inside der, |
| * and *data_len is the length of the payload. */ |
| |
| /* Step 4: payload validation */ |
| if (*data_len > MBEDTLS_X509_MAX_DN_NAME_SIZE) { |
| goto error; |
| } |
| /* Strings must not contain null bytes. */ |
| if (MBEDTLS_ASN1_IS_STRING_TAG(*tag)) { |
| for (size_t i = 0; i < *data_len; i++) { |
| if (p[i] == 0) { |
| goto error; |
| } |
| } |
| } |
| |
| /* Step 5: output the payload. */ |
| if (*data_len > data_size) { |
| goto error; |
| } |
| memcpy(data, p, *data_len); |
| } |
| mbedtls_free(der); |
| |
| return 0; |
| |
| error: |
| mbedtls_free(der); |
| return MBEDTLS_ERR_X509_INVALID_NAME; |
| } |
| |
| int mbedtls_x509_string_to_names(mbedtls_asn1_named_data **head, const char *name) |
| { |
| int ret = MBEDTLS_ERR_X509_INVALID_NAME; |
| int parse_ret = 0; |
| const char *s = name, *c = s; |
| const char *end = s + strlen(s); |
| mbedtls_asn1_buf oid = { .p = NULL, .len = 0, .tag = MBEDTLS_ASN1_NULL }; |
| const x509_attr_descriptor_t *attr_descr = NULL; |
| int in_attr_type = 1; |
| int tag; |
| int numericoid = 0; |
| unsigned char data[MBEDTLS_X509_MAX_DN_NAME_SIZE]; |
| size_t data_len = 0; |
| |
| /* Clear existing chain if present */ |
| mbedtls_asn1_free_named_data_list(head); |
| |
| while (c <= end) { |
| if (in_attr_type && *c == '=') { |
| if ((attr_descr = x509_attr_descr_from_name(s, (size_t) (c - s))) == NULL) { |
| if ((mbedtls_oid_from_numeric_string(&oid, s, (size_t) (c - s))) != 0) { |
| return MBEDTLS_ERR_X509_INVALID_NAME; |
| } else { |
| numericoid = 1; |
| } |
| } else { |
| oid.len = strlen(attr_descr->oid); |
| oid.p = mbedtls_calloc(1, oid.len); |
| memcpy(oid.p, attr_descr->oid, oid.len); |
| numericoid = 0; |
| } |
| |
| s = c + 1; |
| in_attr_type = 0; |
| } |
| |
| if (!in_attr_type && ((*c == ',' && *(c-1) != '\\') || c == end)) { |
| if (s == c) { |
| mbedtls_free(oid.p); |
| return MBEDTLS_ERR_X509_INVALID_NAME; |
| } else if (*s == '#') { |
| /* We know that c >= s (loop invariant) and c != s (in this |
| * else branch), hence c - s - 1 >= 0. */ |
| parse_ret = parse_attribute_value_hex_der_encoded( |
| s + 1, (size_t) (c - s) - 1, |
| data, sizeof(data), &data_len, &tag); |
| if (parse_ret != 0) { |
| mbedtls_free(oid.p); |
| return parse_ret; |
| } |
| } else { |
| if (numericoid) { |
| mbedtls_free(oid.p); |
| return MBEDTLS_ERR_X509_INVALID_NAME; |
| } else { |
| if ((parse_ret = |
| parse_attribute_value_string(s, (int) (c - s), data, |
| &data_len)) != 0) { |
| mbedtls_free(oid.p); |
| return parse_ret; |
| } |
| tag = attr_descr->default_tag; |
| } |
| } |
| |
| mbedtls_asn1_named_data *cur = |
| mbedtls_asn1_store_named_data(head, (char *) oid.p, oid.len, |
| (unsigned char *) data, |
| data_len); |
| mbedtls_free(oid.p); |
| oid.p = NULL; |
| if (cur == NULL) { |
| return MBEDTLS_ERR_X509_ALLOC_FAILED; |
| } |
| |
| // set tagType |
| cur->val.tag = tag; |
| |
| while (c < end && *(c + 1) == ' ') { |
| c++; |
| } |
| |
| s = c + 1; |
| in_attr_type = 1; |
| |
| /* Successfully parsed one name, update ret to success */ |
| ret = 0; |
| } |
| c++; |
| } |
| if (oid.p != NULL) { |
| mbedtls_free(oid.p); |
| } |
| return ret; |
| } |
| |
| /* The first byte of the value in the mbedtls_asn1_named_data structure is reserved |
| * to store the critical boolean for us |
| */ |
| int mbedtls_x509_set_extension(mbedtls_asn1_named_data **head, const char *oid, size_t oid_len, |
| int critical, const unsigned char *val, size_t val_len) |
| { |
| mbedtls_asn1_named_data *cur; |
| |
| if (val_len > (SIZE_MAX - 1)) { |
| return MBEDTLS_ERR_X509_BAD_INPUT_DATA; |
| } |
| |
| if ((cur = mbedtls_asn1_store_named_data(head, oid, oid_len, |
| NULL, val_len + 1)) == NULL) { |
| return MBEDTLS_ERR_X509_ALLOC_FAILED; |
| } |
| |
| cur->val.p[0] = critical; |
| memcpy(cur->val.p + 1, val, val_len); |
| |
| return 0; |
| } |
| |
| /* |
| * RelativeDistinguishedName ::= |
| * SET OF AttributeTypeAndValue |
| * |
| * AttributeTypeAndValue ::= SEQUENCE { |
| * type AttributeType, |
| * value AttributeValue } |
| * |
| * AttributeType ::= OBJECT IDENTIFIER |
| * |
| * AttributeValue ::= ANY DEFINED BY AttributeType |
| */ |
| static int x509_write_name(unsigned char **p, |
| unsigned char *start, |
| mbedtls_asn1_named_data *cur_name) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| size_t len = 0; |
| const char *oid = (const char *) cur_name->oid.p; |
| size_t oid_len = cur_name->oid.len; |
| const unsigned char *name = cur_name->val.p; |
| size_t name_len = cur_name->val.len; |
| |
| // Write correct string tag and value |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tagged_string(p, start, |
| cur_name->val.tag, |
| (const char *) name, |
| name_len)); |
| // Write OID |
| // |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_oid(p, start, oid, |
| oid_len)); |
| |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len)); |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, |
| MBEDTLS_ASN1_CONSTRUCTED | |
| MBEDTLS_ASN1_SEQUENCE)); |
| |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len)); |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, |
| MBEDTLS_ASN1_CONSTRUCTED | |
| MBEDTLS_ASN1_SET)); |
| |
| return (int) len; |
| } |
| |
| int mbedtls_x509_write_names(unsigned char **p, unsigned char *start, |
| mbedtls_asn1_named_data *first) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| size_t len = 0; |
| mbedtls_asn1_named_data *cur = first; |
| |
| while (cur != NULL) { |
| MBEDTLS_ASN1_CHK_ADD(len, x509_write_name(p, start, cur)); |
| cur = cur->next; |
| } |
| |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len)); |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_CONSTRUCTED | |
| MBEDTLS_ASN1_SEQUENCE)); |
| |
| return (int) len; |
| } |
| |
| int mbedtls_x509_write_sig(unsigned char **p, unsigned char *start, |
| const char *oid, size_t oid_len, |
| unsigned char *sig, size_t size, |
| mbedtls_pk_type_t pk_alg) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| int write_null_par; |
| size_t len = 0; |
| |
| if (*p < start || (size_t) (*p - start) < size) { |
| return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL; |
| } |
| |
| len = size; |
| (*p) -= len; |
| memcpy(*p, sig, len); |
| |
| if (*p - start < 1) { |
| return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL; |
| } |
| |
| *--(*p) = 0; |
| len += 1; |
| |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len)); |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_BIT_STRING)); |
| |
| // Write OID |
| // |
| if (pk_alg == MBEDTLS_PK_ECDSA) { |
| /* |
| * The AlgorithmIdentifier's parameters field must be absent for DSA/ECDSA signature |
| * algorithms, see https://www.rfc-editor.org/rfc/rfc5480#page-17 and |
| * https://www.rfc-editor.org/rfc/rfc5758#section-3. |
| */ |
| write_null_par = 0; |
| } else { |
| write_null_par = 1; |
| } |
| MBEDTLS_ASN1_CHK_ADD(len, |
| mbedtls_asn1_write_algorithm_identifier_ext(p, start, oid, oid_len, |
| 0, write_null_par)); |
| |
| return (int) len; |
| } |
| |
| static int x509_write_extension(unsigned char **p, unsigned char *start, |
| mbedtls_asn1_named_data *ext) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| size_t len = 0; |
| |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start, ext->val.p + 1, |
| ext->val.len - 1)); |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, ext->val.len - 1)); |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_OCTET_STRING)); |
| |
| if (ext->val.p[0] != 0) { |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_bool(p, start, 1)); |
| } |
| |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start, ext->oid.p, |
| ext->oid.len)); |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, ext->oid.len)); |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_OID)); |
| |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len)); |
| MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_CONSTRUCTED | |
| MBEDTLS_ASN1_SEQUENCE)); |
| |
| return (int) len; |
| } |
| |
| /* |
| * Extension ::= SEQUENCE { |
| * extnID OBJECT IDENTIFIER, |
| * critical BOOLEAN DEFAULT FALSE, |
| * extnValue OCTET STRING |
| * -- contains the DER encoding of an ASN.1 value |
| * -- corresponding to the extension type identified |
| * -- by extnID |
| * } |
| */ |
| int mbedtls_x509_write_extensions(unsigned char **p, unsigned char *start, |
| mbedtls_asn1_named_data *first) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| size_t len = 0; |
| mbedtls_asn1_named_data *cur_ext = first; |
| |
| while (cur_ext != NULL) { |
| MBEDTLS_ASN1_CHK_ADD(len, x509_write_extension(p, start, cur_ext)); |
| cur_ext = cur_ext->next; |
| } |
| |
| return (int) len; |
| } |
| |
| #endif /* MBEDTLS_X509_CREATE_C */ |
