/*

 *  X.509 Certificate Signing Request (CSR) parsing

 *

 *  Copyright The Mbed TLS Contributors

 *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later

 */

/*

 *  The ITU-T X.509 standard defines a certificate format for PKI.

 *

 *  http://www.ietf.org/rfc/rfc5280.txt (Certificates and CRLs)

 *  http://www.ietf.org/rfc/rfc3279.txt (Alg IDs for CRLs)

 *  http://www.ietf.org/rfc/rfc2986.txt (CSRs, aka PKCS#10)

 *

 *  http://www.itu.int/ITU-T/studygroups/com17/languages/X.680-0207.pdf

 *  http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf

 */

#include "common.h"

#if defined(MBEDTLS_X509_CSR_PARSE_C)

#include "mbedtls/x509_csr.h"

#include "x509_internal.h"

#include "mbedtls/error.h"

#include "mbedtls/oid.h"

#include "mbedtls/platform_util.h"

#include <string.h>

#if defined(MBEDTLS_PEM_PARSE_C)

#include "mbedtls/pem.h"

#endif

#include "mbedtls/platform.h"

#if defined(MBEDTLS_FS_IO) || defined(EFIX64) || defined(EFI32)

#include <stdio.h>

#endif

/*

 *  Version  ::=  INTEGER  {  v1(0)  }

 */

static int x509_csr_get_version(unsigned char **p,

                                const unsigned char *end,

                                int *ver)

{

    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

    if ((ret = mbedtls_asn1_get_int(p, end, ver)) != 0) {

        if (ret == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {

            *ver = 0;

            return 0;

        }

        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_VERSION, ret);

    }

    return 0;

}

/*

 * Parse CSR extension requests in DER format

 */

static int x509_csr_parse_extensions(mbedtls_x509_csr *csr,

                                     unsigned char **p, const unsigned char *end,

                                     mbedtls_x509_csr_ext_cb_t cb,

                                     void *p_ctx)

{

    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

    size_t len;

    unsigned char *end_ext_data, *end_ext_octet;

    while (*p < end) {

        mbedtls_x509_buf extn_oid = { 0, 0, NULL };

        int is_critical = 0; /* DEFAULT FALSE */

        int ext_type = 0;

        /* Read sequence tag */

        if ((ret = mbedtls_asn1_get_tag(p, end, &len,

                                        MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {

            return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);

        }

        end_ext_data = *p + len;

        /* Get extension ID */

        if ((ret = mbedtls_asn1_get_tag(p, end_ext_data, &extn_oid.len,

                                        MBEDTLS_ASN1_OID)) != 0) {

            return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);

        }

        extn_oid.tag = MBEDTLS_ASN1_OID;

        extn_oid.p = *p;

        *p += extn_oid.len;

        /* Get optional critical */

        if ((ret = mbedtls_asn1_get_bool(p, end_ext_data, &is_critical)) != 0 &&

            (ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG)) {

            return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);

        }

        /* Data should be octet string type */

        if ((ret = mbedtls_asn1_get_tag(p, end_ext_data, &len,

                                        MBEDTLS_ASN1_OCTET_STRING)) != 0) {

            return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);

        }

        end_ext_octet = *p + len;

        if (end_ext_octet != end_ext_data) {

            return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,

                                     MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);

        }

        /*

         * Detect supported extensions and skip unsupported extensions

         */

        ret = mbedtls_oid_get_x509_ext_type(&extn_oid, &ext_type);

        if (ret != 0) {

            /* Give the callback (if any) a chance to handle the extension */

            if (cb != NULL) {

                ret = cb(p_ctx, csr, &extn_oid, is_critical, *p, end_ext_octet);

                if (ret != 0 && is_critical) {

                    return ret;

                }

                *p = end_ext_octet;

                continue;

            }

            /* No parser found, skip extension */

            *p = end_ext_octet;

            if (is_critical) {

                /* Data is marked as critical: fail */

                return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,

                                         MBEDTLS_ERR_ASN1_UNEXPECTED_TAG);

            }

            continue;

        }

        /* Forbid repeated extensions */

        if ((csr->ext_types & ext_type) != 0) {

            return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,

                                     MBEDTLS_ERR_ASN1_INVALID_DATA);

        }

        csr->ext_types |= ext_type;

        switch (ext_type) {

            case MBEDTLS_X509_EXT_KEY_USAGE:

                /* Parse key usage */

                if ((ret = mbedtls_x509_get_key_usage(p, end_ext_data,

                                                      &csr->key_usage)) != 0) {

                    return ret;

                }

                break;

            case MBEDTLS_X509_EXT_SUBJECT_ALT_NAME:

                /* Parse subject alt name */

                if ((ret = mbedtls_x509_get_subject_alt_name(p, end_ext_data,

                                                             &csr->subject_alt_names)) != 0) {

                    return ret;

                }

                break;

            case MBEDTLS_X509_EXT_NS_CERT_TYPE:

                /* Parse netscape certificate type */

                if ((ret = mbedtls_x509_get_ns_cert_type(p, end_ext_data,

                                                         &csr->ns_cert_type)) != 0) {

                    return ret;

                }

                break;

            default:

                /*

                 * If this is a non-critical extension, which the oid layer

                 * supports, but there isn't an x509 parser for it,

                 * skip the extension.

                 */

                if (is_critical) {

                    return MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE;

                } else {

                    *p = end_ext_octet;

                }

        }

    }

    if (*p != end) {

        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,

                                 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);

    }

    return 0;

}

/*

 * Parse CSR attributes in DER format

 */

static int x509_csr_parse_attributes(mbedtls_x509_csr *csr,

                                     const unsigned char *start, const unsigned char *end,

                                     mbedtls_x509_csr_ext_cb_t cb,

                                     void *p_ctx)

{

    int ret;

    size_t len;

    unsigned char *end_attr_data;

    unsigned char **p = (unsigned char **) &start;

    while (*p < end) {

        mbedtls_x509_buf attr_oid = { 0, 0, NULL };

        if ((ret = mbedtls_asn1_get_tag(p, end, &len,

                                        MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {

            return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);

        }

        end_attr_data = *p + len;

        /* Get attribute ID */

        if ((ret = mbedtls_asn1_get_tag(p, end_attr_data, &attr_oid.len,

                                        MBEDTLS_ASN1_OID)) != 0) {

            return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);

        }

        attr_oid.tag = MBEDTLS_ASN1_OID;

        attr_oid.p = *p;

        *p += attr_oid.len;

        /* Check that this is an extension-request attribute */

        if (MBEDTLS_OID_CMP(MBEDTLS_OID_PKCS9_CSR_EXT_REQ, &attr_oid) == 0) {

            if ((ret = mbedtls_asn1_get_tag(p, end, &len,

                                            MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SET)) != 0) {

                return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);

            }

            if ((ret = mbedtls_asn1_get_tag(p, end, &len,

                                            MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) !=

                0) {

                return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);

            }

            if ((ret = x509_csr_parse_extensions(csr, p, *p + len, cb, p_ctx)) != 0) {

                return ret;

            }

            if (*p != end_attr_data) {

                return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,

                                         MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);

            }

        }

        *p = end_attr_data;

    }

    if (*p != end) {

        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,

                                 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);

    }

    return 0;

}

/*

 * Parse a CSR in DER format

 */

static int mbedtls_x509_csr_parse_der_internal(mbedtls_x509_csr *csr,

                                               const unsigned char *buf, size_t buflen,

                                               mbedtls_x509_csr_ext_cb_t cb,

                                               void *p_ctx)

{

    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

    size_t len;

    unsigned char *p, *end;

    mbedtls_x509_buf sig_params;

    memset(&sig_params, 0, sizeof(mbedtls_x509_buf));

    /*

     * Check for valid input

     */

    if (csr == NULL || buf == NULL || buflen == 0) {

        return MBEDTLS_ERR_X509_BAD_INPUT_DATA;

    }

    mbedtls_x509_csr_init(csr);

    /*

     * first copy the raw DER data

     */

    p = mbedtls_calloc(1, len = buflen);

    if (p == NULL) {

        return MBEDTLS_ERR_X509_ALLOC_FAILED;

    }

    memcpy(p, buf, buflen);

    csr->raw.p = p;

    csr->raw.len = len;

    end = p + len;

    /*

     *  CertificationRequest ::= SEQUENCE {

     *       certificationRequestInfo CertificationRequestInfo,

     *       signatureAlgorithm AlgorithmIdentifier,

     *       signature          BIT STRING

     *  }

     */

    if ((ret = mbedtls_asn1_get_tag(&p, end, &len,

                                    MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {

        mbedtls_x509_csr_free(csr);

        return MBEDTLS_ERR_X509_INVALID_FORMAT;

    }

    if (len != (size_t) (end - p)) {

        mbedtls_x509_csr_free(csr);

        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_FORMAT,

                                 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);

    }

    /*

     *  CertificationRequestInfo ::= SEQUENCE {

     */

    csr->cri.p = p;

    if ((ret = mbedtls_asn1_get_tag(&p, end, &len,

                                    MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {

        mbedtls_x509_csr_free(csr);

        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_FORMAT, ret);

    }

    end = p + len;

    csr->cri.len = (size_t) (end - csr->cri.p);

    /*

     *  Version  ::=  INTEGER {  v1(0) }

     */

    if ((ret = x509_csr_get_version(&p, end, &csr->version)) != 0) {

        mbedtls_x509_csr_free(csr);

        return ret;

    }

    if (csr->version != 0) {

        mbedtls_x509_csr_free(csr);

        return MBEDTLS_ERR_X509_UNKNOWN_VERSION;

    }

    csr->version++;

    /*

     *  subject               Name

     */

    csr->subject_raw.p = p;

    if ((ret = mbedtls_asn1_get_tag(&p, end, &len,

                                    MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {

        mbedtls_x509_csr_free(csr);

        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_FORMAT, ret);

    }

    if ((ret = mbedtls_x509_get_name(&p, p + len, &csr->subject)) != 0) {

        mbedtls_x509_csr_free(csr);

        return ret;

    }

    csr->subject_raw.len = (size_t) (p - csr->subject_raw.p);

    /*

     *  subjectPKInfo SubjectPublicKeyInfo

     */

    if ((ret = mbedtls_pk_parse_subpubkey(&p, end, &csr->pk)) != 0) {

        mbedtls_x509_csr_free(csr);

        return ret;

    }

    /*

     *  attributes    [0] Attributes

     *

     *  The list of possible attributes is open-ended, though RFC 2985

     *  (PKCS#9) defines a few in section 5.4. We currently don't support any,

     *  so we just ignore them. This is a safe thing to do as the worst thing

     *  that could happen is that we issue a certificate that does not match

     *  the requester's expectations - this cannot cause a violation of our

     *  signature policies.

     */

    if ((ret = mbedtls_asn1_get_tag(&p, end, &len,

                                    MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_CONTEXT_SPECIFIC)) !=

        0) {

        mbedtls_x509_csr_free(csr);

        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_FORMAT, ret);

    }

    if ((ret = x509_csr_parse_attributes(csr, p, p + len, cb, p_ctx)) != 0) {

        mbedtls_x509_csr_free(csr);

        return ret;

    }

    p += len;

    end = csr->raw.p + csr->raw.len;

    /*

     *  signatureAlgorithm   AlgorithmIdentifier,

     *  signature            BIT STRING

     */

    if ((ret = mbedtls_x509_get_alg(&p, end, &csr->sig_oid, &sig_params)) != 0) {

        mbedtls_x509_csr_free(csr);

        return ret;

    }

    if ((ret = mbedtls_x509_get_sig_alg(&csr->sig_oid, &sig_params,

                                        &csr->sig_md, &csr->sig_pk,

                                        &csr->sig_opts)) != 0) {

        mbedtls_x509_csr_free(csr);

        return MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG;

    }

    if ((ret = mbedtls_x509_get_sig(&p, end, &csr->sig)) != 0) {

        mbedtls_x509_csr_free(csr);

        return ret;

    }

    if (p != end) {

        mbedtls_x509_csr_free(csr);

        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_FORMAT,

                                 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);

    }

    return 0;

}

/*

 * Parse a CSR in DER format

 */

int mbedtls_x509_csr_parse_der(mbedtls_x509_csr *csr,

                               const unsigned char *buf, size_t buflen)

{

    return mbedtls_x509_csr_parse_der_internal(csr, buf, buflen, NULL, NULL);

}

/*

 * Parse a CSR in DER format with callback for unknown extensions

 */

int mbedtls_x509_csr_parse_der_with_ext_cb(mbedtls_x509_csr *csr,

                                           const unsigned char *buf, size_t buflen,

                                           mbedtls_x509_csr_ext_cb_t cb,

                                           void *p_ctx)

{

    return mbedtls_x509_csr_parse_der_internal(csr, buf, buflen, cb, p_ctx);

}

/*

 * Parse a CSR, allowing for PEM or raw DER encoding

 */

int mbedtls_x509_csr_parse(mbedtls_x509_csr *csr, const unsigned char *buf, size_t buflen)

{

#if defined(MBEDTLS_PEM_PARSE_C)

    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

    size_t use_len;

    mbedtls_pem_context pem;

#endif

    /*

     * Check for valid input

     */

    if (csr == NULL || buf == NULL || buflen == 0) {

        return MBEDTLS_ERR_X509_BAD_INPUT_DATA;

    }

#if defined(MBEDTLS_PEM_PARSE_C)

    /* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */

    if (buf[buflen - 1] == '\0') {

        mbedtls_pem_init(&pem);

        ret = mbedtls_pem_read_buffer(&pem,

                                      "-----BEGIN CERTIFICATE REQUEST-----",

                                      "-----END CERTIFICATE REQUEST-----",

                                      buf, NULL, 0, &use_len);

        if (ret == MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT) {

            ret = mbedtls_pem_read_buffer(&pem,

                                          "-----BEGIN NEW CERTIFICATE REQUEST-----",

                                          "-----END NEW CERTIFICATE REQUEST-----",

                                          buf, NULL, 0, &use_len);

        }

        if (ret == 0) {

            /*

             * Was PEM encoded, parse the result

             */

            ret = mbedtls_x509_csr_parse_der(csr, pem.buf, pem.buflen);

        }

        mbedtls_pem_free(&pem);

        if (ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT) {

            return ret;

        }

    }

#endif /* MBEDTLS_PEM_PARSE_C */

    return mbedtls_x509_csr_parse_der(csr, buf, buflen);

}

#if defined(MBEDTLS_FS_IO)

/*

 * Load a CSR into the structure

 */

int mbedtls_x509_csr_parse_file(mbedtls_x509_csr *csr, const char *path)

{

    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

    size_t n;

    unsigned char *buf;

    if ((ret = mbedtls_pk_load_file(path, &buf, &n)) != 0) {

        return ret;

    }

    ret = mbedtls_x509_csr_parse(csr, buf, n);

    mbedtls_zeroize_and_free(buf, n);

    return ret;

}

#endif /* MBEDTLS_FS_IO */

#if !defined(MBEDTLS_X509_REMOVE_INFO)

#define BEFORE_COLON    14

#define BC              "14"

/*

 * Return an informational string about the CSR.

 */

int mbedtls_x509_csr_info(char *buf, size_t size, const char *prefix,

                          const mbedtls_x509_csr *csr)

{

    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

    size_t n;

    char *p;

    char key_size_str[BEFORE_COLON];

    p = buf;

    n = size;

    ret = mbedtls_snprintf(p, n, "%sCSR version   : %d",

                           prefix, csr->version);

    MBEDTLS_X509_SAFE_SNPRINTF;

    ret = mbedtls_snprintf(p, n, "\n%ssubject name  : ", prefix);

    MBEDTLS_X509_SAFE_SNPRINTF;

    ret = mbedtls_x509_dn_gets(p, n, &csr->subject);

    MBEDTLS_X509_SAFE_SNPRINTF;

    ret = mbedtls_snprintf(p, n, "\n%ssigned using  : ", prefix);

    MBEDTLS_X509_SAFE_SNPRINTF;

    ret = mbedtls_x509_sig_alg_gets(p, n, &csr->sig_oid, csr->sig_pk, csr->sig_md,

                                    csr->sig_opts);

    MBEDTLS_X509_SAFE_SNPRINTF;

    if ((ret = mbedtls_x509_key_size_helper(key_size_str, BEFORE_COLON,

                                            mbedtls_pk_get_name(&csr->pk))) != 0) {

        return ret;

    }

    ret = mbedtls_snprintf(p, n, "\n%s%-" BC "s: %d bits\n", prefix, key_size_str,

                           (int) mbedtls_pk_get_bitlen(&csr->pk));

    MBEDTLS_X509_SAFE_SNPRINTF;

    /*

     * Optional extensions

     */

    if (csr->ext_types & MBEDTLS_X509_EXT_SUBJECT_ALT_NAME) {

        ret = mbedtls_snprintf(p, n, "\n%ssubject alt name  :", prefix);

        MBEDTLS_X509_SAFE_SNPRINTF;

        if ((ret = mbedtls_x509_info_subject_alt_name(&p, &n,

                                                      &csr->subject_alt_names,

                                                      prefix)) != 0) {

            return ret;

        }

    }

    if (csr->ext_types & MBEDTLS_X509_EXT_NS_CERT_TYPE) {

        ret = mbedtls_snprintf(p, n, "\n%scert. type        : ", prefix);

        MBEDTLS_X509_SAFE_SNPRINTF;

        if ((ret = mbedtls_x509_info_cert_type(&p, &n, csr->ns_cert_type)) != 0) {

            return ret;

        }

    }

    if (csr->ext_types & MBEDTLS_X509_EXT_KEY_USAGE) {

        ret = mbedtls_snprintf(p, n, "\n%skey usage         : ", prefix);

        MBEDTLS_X509_SAFE_SNPRINTF;

        if ((ret = mbedtls_x509_info_key_usage(&p, &n, csr->key_usage)) != 0) {

            return ret;

        }

    }

    if (csr->ext_types != 0) {

        ret = mbedtls_snprintf(p, n, "\n");

        MBEDTLS_X509_SAFE_SNPRINTF;

    }

    return (int) (size - n);

}

#endif /* MBEDTLS_X509_REMOVE_INFO */

/*

 * Initialize a CSR

 */

void mbedtls_x509_csr_init(mbedtls_x509_csr *csr)

{

    memset(csr, 0, sizeof(mbedtls_x509_csr));

}

/*

 * Unallocate all CSR data

 */

void mbedtls_x509_csr_free(mbedtls_x509_csr *csr)

{

    if (csr == NULL) {

        return;

    }

    mbedtls_pk_free(&csr->pk);

#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)

    mbedtls_free(csr->sig_opts);

#endif

    mbedtls_asn1_free_named_data_list_shallow(csr->subject.next);

    mbedtls_asn1_sequence_free(csr->subject_alt_names.next);

    if (csr->raw.p != NULL) {

        mbedtls_zeroize_and_free(csr->raw.p, csr->raw.len);

    }

    mbedtls_platform_zeroize(csr, sizeof(mbedtls_x509_csr));

}

#endif /* MBEDTLS_X509_CSR_PARSE_C */