393 lines
11 KiB
C
393 lines
11 KiB
C
/*
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* X.509 Certificate Signing Request (CSR) parsing
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*
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* Copyright The Mbed TLS Contributors
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*
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* The ITU-T X.509 standard defines a certificate format for PKI.
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*
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* http://www.ietf.org/rfc/rfc5280.txt (Certificates and CRLs)
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* http://www.ietf.org/rfc/rfc3279.txt (Alg IDs for CRLs)
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* http://www.ietf.org/rfc/rfc2986.txt (CSRs, aka PKCS#10)
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*
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* http://www.itu.int/ITU-T/studygroups/com17/languages/X.680-0207.pdf
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* http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf
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*/
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#include "common.h"
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#if defined(MBEDTLS_X509_CSR_PARSE_C)
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#include "mbedtls/x509_csr.h"
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#include "mbedtls/error.h"
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#include "mbedtls/oid.h"
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#include "mbedtls/platform_util.h"
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#include <string.h>
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#if defined(MBEDTLS_PEM_PARSE_C)
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#include "mbedtls/pem.h"
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#endif
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#include "mbedtls/platform.h"
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#if defined(MBEDTLS_FS_IO) || defined(EFIX64) || defined(EFI32)
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#include <stdio.h>
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#endif
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/*
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* Version ::= INTEGER { v1(0) }
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*/
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static int x509_csr_get_version(unsigned char **p,
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const unsigned char *end,
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int *ver)
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{
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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if ((ret = mbedtls_asn1_get_int(p, end, ver)) != 0) {
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if (ret == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {
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*ver = 0;
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return 0;
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}
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return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_VERSION, ret);
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}
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return 0;
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}
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/*
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* Parse a CSR in DER format
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*/
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int mbedtls_x509_csr_parse_der(mbedtls_x509_csr *csr,
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const unsigned char *buf, size_t buflen)
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{
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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size_t len;
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unsigned char *p, *end;
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mbedtls_x509_buf sig_params;
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memset(&sig_params, 0, sizeof(mbedtls_x509_buf));
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/*
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* Check for valid input
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*/
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if (csr == NULL || buf == NULL || buflen == 0) {
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return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
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}
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mbedtls_x509_csr_init(csr);
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/*
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* first copy the raw DER data
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*/
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p = mbedtls_calloc(1, len = buflen);
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if (p == NULL) {
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return MBEDTLS_ERR_X509_ALLOC_FAILED;
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}
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memcpy(p, buf, buflen);
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csr->raw.p = p;
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csr->raw.len = len;
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end = p + len;
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/*
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* CertificationRequest ::= SEQUENCE {
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* certificationRequestInfo CertificationRequestInfo,
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* signatureAlgorithm AlgorithmIdentifier,
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* signature BIT STRING
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* }
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*/
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if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
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MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
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mbedtls_x509_csr_free(csr);
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return MBEDTLS_ERR_X509_INVALID_FORMAT;
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}
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if (len != (size_t) (end - p)) {
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mbedtls_x509_csr_free(csr);
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return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_FORMAT,
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MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
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}
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/*
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* CertificationRequestInfo ::= SEQUENCE {
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*/
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csr->cri.p = p;
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if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
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MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
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mbedtls_x509_csr_free(csr);
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return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_FORMAT, ret);
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}
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end = p + len;
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csr->cri.len = end - csr->cri.p;
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/*
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* Version ::= INTEGER { v1(0) }
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*/
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if ((ret = x509_csr_get_version(&p, end, &csr->version)) != 0) {
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mbedtls_x509_csr_free(csr);
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return ret;
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}
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if (csr->version != 0) {
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mbedtls_x509_csr_free(csr);
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return MBEDTLS_ERR_X509_UNKNOWN_VERSION;
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}
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csr->version++;
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/*
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* subject Name
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*/
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csr->subject_raw.p = p;
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if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
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MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
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mbedtls_x509_csr_free(csr);
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return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_FORMAT, ret);
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}
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if ((ret = mbedtls_x509_get_name(&p, p + len, &csr->subject)) != 0) {
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mbedtls_x509_csr_free(csr);
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return ret;
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}
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csr->subject_raw.len = p - csr->subject_raw.p;
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/*
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* subjectPKInfo SubjectPublicKeyInfo
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*/
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if ((ret = mbedtls_pk_parse_subpubkey(&p, end, &csr->pk)) != 0) {
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mbedtls_x509_csr_free(csr);
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return ret;
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}
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/*
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* attributes [0] Attributes
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*
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* The list of possible attributes is open-ended, though RFC 2985
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* (PKCS#9) defines a few in section 5.4. We currently don't support any,
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* so we just ignore them. This is a safe thing to do as the worst thing
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* that could happen is that we issue a certificate that does not match
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* the requester's expectations - this cannot cause a violation of our
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* signature policies.
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*/
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if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
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MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_CONTEXT_SPECIFIC)) !=
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0) {
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mbedtls_x509_csr_free(csr);
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return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_FORMAT, ret);
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}
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p += len;
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end = csr->raw.p + csr->raw.len;
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/*
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* signatureAlgorithm AlgorithmIdentifier,
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* signature BIT STRING
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*/
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if ((ret = mbedtls_x509_get_alg(&p, end, &csr->sig_oid, &sig_params)) != 0) {
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mbedtls_x509_csr_free(csr);
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return ret;
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}
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if ((ret = mbedtls_x509_get_sig_alg(&csr->sig_oid, &sig_params,
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&csr->sig_md, &csr->sig_pk,
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&csr->sig_opts)) != 0) {
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mbedtls_x509_csr_free(csr);
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return MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG;
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}
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if ((ret = mbedtls_x509_get_sig(&p, end, &csr->sig)) != 0) {
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mbedtls_x509_csr_free(csr);
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return ret;
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}
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if (p != end) {
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mbedtls_x509_csr_free(csr);
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return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_FORMAT,
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MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
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}
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return 0;
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}
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/*
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* Parse a CSR, allowing for PEM or raw DER encoding
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*/
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int mbedtls_x509_csr_parse(mbedtls_x509_csr *csr, const unsigned char *buf, size_t buflen)
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{
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#if defined(MBEDTLS_PEM_PARSE_C)
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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size_t use_len;
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mbedtls_pem_context pem;
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#endif
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/*
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* Check for valid input
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*/
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if (csr == NULL || buf == NULL || buflen == 0) {
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return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
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}
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#if defined(MBEDTLS_PEM_PARSE_C)
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/* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */
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if (buf[buflen - 1] == '\0') {
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mbedtls_pem_init(&pem);
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ret = mbedtls_pem_read_buffer(&pem,
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"-----BEGIN CERTIFICATE REQUEST-----",
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"-----END CERTIFICATE REQUEST-----",
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buf, NULL, 0, &use_len);
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if (ret == MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT) {
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ret = mbedtls_pem_read_buffer(&pem,
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"-----BEGIN NEW CERTIFICATE REQUEST-----",
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"-----END NEW CERTIFICATE REQUEST-----",
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buf, NULL, 0, &use_len);
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}
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if (ret == 0) {
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/*
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* Was PEM encoded, parse the result
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*/
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ret = mbedtls_x509_csr_parse_der(csr, pem.buf, pem.buflen);
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}
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mbedtls_pem_free(&pem);
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if (ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT) {
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return ret;
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}
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}
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#endif /* MBEDTLS_PEM_PARSE_C */
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return mbedtls_x509_csr_parse_der(csr, buf, buflen);
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}
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#if defined(MBEDTLS_FS_IO)
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/*
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* Load a CSR into the structure
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*/
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int mbedtls_x509_csr_parse_file(mbedtls_x509_csr *csr, const char *path)
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{
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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size_t n;
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unsigned char *buf;
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if ((ret = mbedtls_pk_load_file(path, &buf, &n)) != 0) {
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return ret;
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}
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ret = mbedtls_x509_csr_parse(csr, buf, n);
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mbedtls_platform_zeroize(buf, n);
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mbedtls_free(buf);
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return ret;
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}
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#endif /* MBEDTLS_FS_IO */
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#define BEFORE_COLON 14
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#define BC "14"
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/*
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* Return an informational string about the CSR.
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*/
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int mbedtls_x509_csr_info(char *buf, size_t size, const char *prefix,
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const mbedtls_x509_csr *csr)
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{
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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size_t n;
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char *p;
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char key_size_str[BEFORE_COLON];
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p = buf;
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n = size;
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ret = mbedtls_snprintf(p, n, "%sCSR version : %d",
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prefix, csr->version);
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MBEDTLS_X509_SAFE_SNPRINTF;
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ret = mbedtls_snprintf(p, n, "\n%ssubject name : ", prefix);
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MBEDTLS_X509_SAFE_SNPRINTF;
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ret = mbedtls_x509_dn_gets(p, n, &csr->subject);
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MBEDTLS_X509_SAFE_SNPRINTF;
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ret = mbedtls_snprintf(p, n, "\n%ssigned using : ", prefix);
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MBEDTLS_X509_SAFE_SNPRINTF;
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ret = mbedtls_x509_sig_alg_gets(p, n, &csr->sig_oid, csr->sig_pk, csr->sig_md,
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csr->sig_opts);
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MBEDTLS_X509_SAFE_SNPRINTF;
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if ((ret = mbedtls_x509_key_size_helper(key_size_str, BEFORE_COLON,
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mbedtls_pk_get_name(&csr->pk))) != 0) {
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return ret;
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}
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ret = mbedtls_snprintf(p, n, "\n%s%-" BC "s: %d bits\n", prefix, key_size_str,
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(int) mbedtls_pk_get_bitlen(&csr->pk));
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MBEDTLS_X509_SAFE_SNPRINTF;
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return (int) (size - n);
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}
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/*
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* Initialize a CSR
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*/
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void mbedtls_x509_csr_init(mbedtls_x509_csr *csr)
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{
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memset(csr, 0, sizeof(mbedtls_x509_csr));
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}
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/*
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* Unallocate all CSR data
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*/
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void mbedtls_x509_csr_free(mbedtls_x509_csr *csr)
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{
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mbedtls_x509_name *name_cur;
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mbedtls_x509_name *name_prv;
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if (csr == NULL) {
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return;
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}
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mbedtls_pk_free(&csr->pk);
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#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
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mbedtls_free(csr->sig_opts);
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#endif
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name_cur = csr->subject.next;
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while (name_cur != NULL) {
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name_prv = name_cur;
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name_cur = name_cur->next;
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mbedtls_platform_zeroize(name_prv, sizeof(mbedtls_x509_name));
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mbedtls_free(name_prv);
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}
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if (csr->raw.p != NULL) {
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mbedtls_platform_zeroize(csr->raw.p, csr->raw.len);
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mbedtls_free(csr->raw.p);
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}
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mbedtls_platform_zeroize(csr, sizeof(mbedtls_x509_csr));
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}
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#endif /* MBEDTLS_X509_CSR_PARSE_C */
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