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6dcfdf1f48a1b146520aa4162b69bcd571b5cc6c
mbedtls/library/x509_csr.c
Stefan Gloor b5c079b13c fix: rename BEFORE_COLON and BC to avoid conflicts 
Namespace BEFORE_COLON and BC defines by prepending MBEDTLS_
and expanding BC to BEFORE_COLON_STR. This is to avoid naming
conflicts with third-party code. No functional change.

Signed-off-by: Stefan Gloor <stefan.gloor@siemens.com>
2025-02-21 10:33:51 +01:00

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/*
* 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 "x509_internal.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 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 MBEDTLS_BEFORE_COLON 14
#define MBEDTLS_BEFORE_COLON_STR "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[MBEDTLS_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, MBEDTLS_BEFORE_COLON,
mbedtls_pk_get_name(&csr->pk))) != 0) {
return ret;
}
ret = mbedtls_snprintf(p, n, "\n%s%-" MBEDTLS_BEFORE_COLON_STR "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 */
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