/*

 *  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 "mbedtls/x509.h"

#include "mbedtls/asn1write.h"

#include "mbedtls/error.h"

#include "mbedtls/oid.h"

#include <string.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. */

    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;

}

int mbedtls_x509_string_to_names(mbedtls_asn1_named_data **head, const char *name)

{

    int ret = MBEDTLS_ERR_X509_INVALID_NAME;

    const char *s = name, *c = s;

    const char *end = s + strlen(s);

    const char *oid = NULL;

    const x509_attr_descriptor_t *attr_descr = NULL;

    int in_tag = 1;

    char data[MBEDTLS_X509_MAX_DN_NAME_SIZE];

    char *d = data;

    /* Clear existing chain if present */

    mbedtls_asn1_free_named_data_list(head);

    while (c <= end) {

        if (in_tag && *c == '=') {

            if ((attr_descr = x509_attr_descr_from_name(s, c - s)) == NULL) {

                ret = MBEDTLS_ERR_X509_UNKNOWN_OID;

                goto exit;

            }

            oid = attr_descr->oid;

            s = c + 1;

            in_tag = 0;

            d = data;

        }

        if (!in_tag && *c == '\\' && c != end) {

            c++;

            /* Check for valid escaped characters */

            if (c == end || *c != ',') {

                ret = MBEDTLS_ERR_X509_INVALID_NAME;

                goto exit;

            }

        } else if (!in_tag && (*c == ',' || c == end)) {

            mbedtls_asn1_named_data *cur =

                mbedtls_asn1_store_named_data(head, oid, strlen(oid),

                                              (unsigned char *) data,

                                              d - data);

            if (cur == NULL) {

                return MBEDTLS_ERR_X509_ALLOC_FAILED;

            }

            // set tagType

            cur->val.tag = attr_descr->default_tag;

            while (c < end && *(c + 1) == ' ') {

                c++;

            }

            s = c + 1;

            in_tag = 1;

            /* Successfully parsed one name, update ret to success */

            ret = 0;

        }

        if (!in_tag && s != c + 1) {

            *(d++) = *c;

            if (d - data == MBEDTLS_X509_MAX_DN_NAME_SIZE) {

                ret = MBEDTLS_ERR_X509_INVALID_NAME;

                goto exit;

            }

        }

        c++;

    }

exit:

    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 */