#include "third_party/mbedtls/asn1write.h"
#include "third_party/mbedtls/common.h"
#include "third_party/mbedtls/error.h"
#include "third_party/mbedtls/oid.h"
#include "third_party/mbedtls/pem.h"
#include "third_party/mbedtls/platform.h"
#include "third_party/mbedtls/x509_csr.h"
asm(".ident\t\"\\n\\n\
Mbed TLS (Apache 2.0)\\n\
Copyright ARM Limited\\n\
Copyright Mbed TLS Contributors\"");
asm(".include \"libc/disclaimer.inc\"");
/* clang-format off */
/*
* X.509 Certificate Signing Request writing
*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* References:
* - CSRs: PKCS#10 v1.7 aka RFC 2986
* - attributes: PKCS#9 v2.0 aka RFC 2985
*/
#if defined(MBEDTLS_X509_CSR_WRITE_C)
/**
* \brief Initialize a CSR context
*
* \param ctx CSR context to initialize
*/
void mbedtls_x509write_csr_init( mbedtls_x509write_csr *ctx )
{
memset( ctx, 0, sizeof( mbedtls_x509write_csr ) );
}
/**
* \brief Free the contents of a CSR context
*
* \param ctx CSR context to free
*/
void mbedtls_x509write_csr_free( mbedtls_x509write_csr *ctx )
{
mbedtls_asn1_free_named_data_list( &ctx->subject );
mbedtls_asn1_free_named_data_list( &ctx->extensions );
mbedtls_platform_zeroize( ctx, sizeof( mbedtls_x509write_csr ) );
}
/**
* \brief Set the MD algorithm to use for the signature
* (e.g. MBEDTLS_MD_SHA1)
*
* \param ctx CSR context to use
* \param md_alg MD algorithm to use
*/
void mbedtls_x509write_csr_set_md_alg( mbedtls_x509write_csr *ctx, mbedtls_md_type_t md_alg )
{
ctx->md_alg = md_alg;
}
/**
* \brief Set the key for a CSR (public key will be included,
* private key used to sign the CSR when writing it)
*
* \param ctx CSR context to use
* \param key Asymetric key to include
*/
void mbedtls_x509write_csr_set_key( mbedtls_x509write_csr *ctx, mbedtls_pk_context *key )
{
ctx->key = key;
}
/**
* \brief Set the subject name for a CSR
* Subject names should contain a comma-separated list
* of OID types and values:
* e.g. "C=UK,O=ARM,CN=mbed TLS Server 1"
*
* \param ctx CSR context to use
* \param subject_name subject name to set
*
* \return 0 if subject name was parsed successfully, or
* a specific error code
*/
int mbedtls_x509write_csr_set_subject_name( mbedtls_x509write_csr *ctx,
const char *subject_name )
{
return mbedtls_x509_string_to_names( &ctx->subject, subject_name );
}
/**
* \brief Generic function to add to or replace an extension in the
* CSR
*
* \param ctx CSR context to use
* \param oid OID of the extension
* \param oid_len length of the OID
* \param val value of the extension OCTET STRING
* \param val_len length of the value data
*
* \return 0 if successful, or a MBEDTLS_ERR_X509_ALLOC_FAILED
*/
int mbedtls_x509write_csr_set_extension( mbedtls_x509write_csr *ctx,
const char *oid, size_t oid_len,
const unsigned char *val, size_t val_len )
{
return mbedtls_x509_set_extension( &ctx->extensions, oid, oid_len,
0, val, val_len );
}
/**
* \brief Set the Key Usage Extension flags
* (e.g. MBEDTLS_X509_KU_DIGITAL_SIGNATURE | MBEDTLS_X509_KU_KEY_CERT_SIGN)
*
* \param ctx CSR context to use
* \param key_usage key usage flags to set
*
* \return 0 if successful, or MBEDTLS_ERR_X509_ALLOC_FAILED
*
* \note The decipherOnly flag from the Key Usage
* extension is represented by bit 8 (i.e.
* 0x8000), which cannot typically be represented
* in an unsigned char. Therefore, the flag
* decipherOnly (i.e.
* #MBEDTLS_X509_KU_DECIPHER_ONLY) cannot be set using this
* function.
*/
int mbedtls_x509write_csr_set_key_usage( mbedtls_x509write_csr *ctx, unsigned char key_usage )
{
unsigned char buf[4];
unsigned char *c;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
c = buf + 4;
ret = mbedtls_asn1_write_named_bitstring( &c, buf, &key_usage, 8 );
if( ret < 3 || ret > 4 )
return ret;
ret = mbedtls_x509write_csr_set_extension( ctx, MBEDTLS_OID_KEY_USAGE,
MBEDTLS_OID_SIZE( MBEDTLS_OID_KEY_USAGE ),
c, (size_t)ret );
if( ret != 0 )
return ret;
return 0;
}
/**
* \brief Set the Netscape Cert Type flags
* (e.g. MBEDTLS_X509_NS_CERT_TYPE_SSL_CLIENT | MBEDTLS_X509_NS_CERT_TYPE_EMAIL)
*
* \param ctx CSR context to use
* \param ns_cert_type Netscape Cert Type flags to set
*
* \return 0 if successful, or MBEDTLS_ERR_X509_ALLOC_FAILED
*/
int mbedtls_x509write_csr_set_ns_cert_type( mbedtls_x509write_csr *ctx,
unsigned char ns_cert_type )
{
unsigned char buf[4];
unsigned char *c;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
c = buf + 4;
ret = mbedtls_asn1_write_named_bitstring( &c, buf, &ns_cert_type, 8 );
if( ret < 3 || ret > 4 )
return ret;
ret = mbedtls_x509write_csr_set_extension( ctx, MBEDTLS_OID_NS_CERT_TYPE,
MBEDTLS_OID_SIZE( MBEDTLS_OID_NS_CERT_TYPE ),
c, (size_t)ret );
if( ret != 0 )
return ret;
return 0;
}
static int x509write_csr_der_internal( mbedtls_x509write_csr *ctx,
unsigned char *buf,
size_t size,
unsigned char *sig,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
const char *sig_oid;
size_t sig_oid_len = 0;
unsigned char *c, *c2;
unsigned char hash[64];
size_t pub_len = 0, sig_and_oid_len = 0, sig_len;
size_t len = 0;
mbedtls_pk_type_t pk_alg;
/* Write the CSR backwards starting from the end of buf */
c = buf + size;
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_extensions( &c, buf,
ctx->extensions ) );
if( len )
{
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_asn1_write_tag(
&c, buf,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_asn1_write_tag(
&c, buf,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SET ) );
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_asn1_write_oid(
&c, buf, MBEDTLS_OID_PKCS9_CSR_EXT_REQ,
MBEDTLS_OID_SIZE( MBEDTLS_OID_PKCS9_CSR_EXT_REQ ) ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_asn1_write_tag(
&c, buf,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) );
}
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_asn1_write_tag(
&c, buf,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_CONTEXT_SPECIFIC ) );
MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_pk_write_pubkey_der( ctx->key,
buf, c - buf ) );
c -= pub_len;
len += pub_len;
/*
* Subject ::= Name
*/
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_names( &c, buf,
ctx->subject ) );
/*
* Version ::= INTEGER { v1(0), v2(1), v3(2) }
*/
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, buf, 0 ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_asn1_write_tag(
&c, buf,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) );
/*
* Sign the written CSR data into the sig buffer
* Note: hash errors can happen only after an internal error
*/
ret = mbedtls_md( mbedtls_md_info_from_type( ctx->md_alg ), c, len, hash );
if( ret != 0 )
return ret;
if( ( ret = mbedtls_pk_sign( ctx->key, ctx->md_alg, hash, 0, sig, &sig_len,
f_rng, p_rng ) ) != 0 )
{
return ret;
}
if( mbedtls_pk_can_do( ctx->key, MBEDTLS_PK_RSA ) )
pk_alg = MBEDTLS_PK_RSA;
else if( mbedtls_pk_can_do( ctx->key, MBEDTLS_PK_ECDSA ) )
pk_alg = MBEDTLS_PK_ECDSA;
else
return( MBEDTLS_ERR_X509_INVALID_ALG );
if( ( ret = mbedtls_oid_get_oid_by_sig_alg( pk_alg, ctx->md_alg,
&sig_oid, &sig_oid_len ) ) != 0 )
{
return ret;
}
/*
* Move the written CSR data to the start of buf to create space for
* writing the signature into buf.
*/
memmove( buf, c, len );
/*
* Write sig and its OID into buf backwards from the end of buf.
* Note: mbedtls_x509_write_sig will check for c2 - ( buf + len ) < sig_len
* and return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL if needed.
*/
c2 = buf + size;
MBEDTLS_ASN1_CHK_ADD( sig_and_oid_len,
mbedtls_x509_write_sig( &c2, buf + len, sig_oid, sig_oid_len,
sig, sig_len ) );
/*
* Compact the space between the CSR data and signature by moving the
* CSR data to the start of the signature.
*/
c2 -= len;
memmove( c2, buf, len );
/* ASN encode the total size and tag the CSR data with it. */
len += sig_and_oid_len;
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c2, buf, len ) );
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_asn1_write_tag(
&c2, buf,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) );
/* Zero the unused bytes at the start of buf */
memset( buf, 0, c2 - buf);
return( (int) len );
}
/**
* \brief Write a CSR (Certificate Signing Request) to a
* DER structure
* Note: data is written at the end of the buffer! Use the
* return value to determine where you should start
* using the buffer
*
* \param ctx CSR to write away
* \param buf buffer to write to
* \param size size of the buffer
* \param f_rng RNG function (for signature, see note)
* \param p_rng RNG parameter
*
* \return length of data written if successful, or a specific
* error code
*
* \note f_rng may be NULL if RSA is used for signature and the
* signature is made offline (otherwise f_rng is desirable
* for countermeasures against timing attacks).
* ECDSA signatures always require a non-NULL f_rng.
*/
int mbedtls_x509write_csr_der( mbedtls_x509write_csr *ctx, unsigned char *buf,
size_t size,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
int ret;
unsigned char *sig;
if( ( sig = mbedtls_calloc( 1, MBEDTLS_PK_SIGNATURE_MAX_SIZE ) ) == NULL )
{
return( MBEDTLS_ERR_X509_ALLOC_FAILED );
}
ret = x509write_csr_der_internal( ctx, buf, size, sig, f_rng, p_rng );
mbedtls_free( sig );
return ret;
}
#define PEM_BEGIN_CSR "-----BEGIN CERTIFICATE REQUEST-----\n"
#define PEM_END_CSR "-----END CERTIFICATE REQUEST-----\n"
/**
* \brief Write a CSR (Certificate Signing Request) to a
* PEM string
*
* \param ctx CSR to write away
* \param buf buffer to write to
* \param size size of the buffer
* \param f_rng RNG function (for signature, see note)
* \param p_rng RNG parameter
*
* \return 0 if successful, or a specific error code
*
* \note f_rng may be NULL if RSA is used for signature and the
* signature is made offline (otherwise f_rng is desirable
* for countermeasures against timing attacks).
* ECDSA signatures always require a non-NULL f_rng.
*/
int mbedtls_x509write_csr_pem( mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t olen = 0;
if( ( ret = mbedtls_x509write_csr_der( ctx, buf, size,
f_rng, p_rng ) ) < 0 )
{
return ret;
}
if( ( ret = mbedtls_pem_write_buffer( PEM_BEGIN_CSR, PEM_END_CSR,
buf + size - ret,
ret, buf, size, &olen ) ) != 0 )
{
return ret;
}
return 0;
}
#endif /* MBEDTLS_X509_CSR_WRITE_C */