/*
* 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 "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 a CSR in DER format
*/
int mbedtls_x509_csr_parse_der(mbedtls_x509_csr *csr,
const unsigned char *buf, size_t buflen)
{
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 = 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 = 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);
}
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, 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_platform_zeroize(buf, n);
mbedtls_free(buf);
return ret;
}
#endif /* MBEDTLS_FS_IO */
#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;
return (int) (size - n);
}
/*
* 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)
{
mbedtls_x509_name *name_cur;
mbedtls_x509_name *name_prv;
if (csr == NULL) {
return;
}
mbedtls_pk_free(&csr->pk);
#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
mbedtls_free(csr->sig_opts);
#endif
name_cur = csr->subject.next;
while (name_cur != NULL) {
name_prv = name_cur;
name_cur = name_cur->next;
mbedtls_platform_zeroize(name_prv, sizeof(mbedtls_x509_name));
mbedtls_free(name_prv);
}
if (csr->raw.p != NULL) {
mbedtls_platform_zeroize(csr->raw.p, csr->raw.len);
mbedtls_free(csr->raw.p);
}
mbedtls_platform_zeroize(csr, sizeof(mbedtls_x509_csr));
}
#endif /* MBEDTLS_X509_CSR_PARSE_C */