M2_SETI/A1/TP/axtls-code/ssl/gen_cert.c
2022-11-28 11:40:47 +01:00

370 lines
11 KiB
C

/*
* Copyright (c) 2007-2014, Cameron Rich
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* * Neither the name of the axTLS project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#ifdef CONFIG_SSL_GENERATE_X509_CERT
#include <string.h>
#include <stdlib.h>
#include "os_port.h"
#include "ssl.h"
/**
* Generate a basic X.509 certificate
*/
static uint8_t set_gen_length(int len, uint8_t *buf, int *offset)
{
if (len < 0x80) /* short form */
{
buf[(*offset)++] = len;
return 1;
}
else /* long form */
{
int i, length_bytes = 0;
if (len & 0x00FF0000)
length_bytes = 3;
else if (len & 0x0000FF00)
length_bytes = 2;
else if (len & 0x000000FF)
length_bytes = 1;
buf[(*offset)++] = 0x80 + length_bytes;
for (i = length_bytes-1; i >= 0; i--)
{
buf[*offset+i] = len & 0xFF;
len >>= 8;
}
*offset += length_bytes;
return length_bytes+1;
}
}
static int pre_adjust_with_size(uint8_t type,
int *seq_offset, uint8_t *buf, int *offset)
{
buf[(*offset)++] = type;
*seq_offset = *offset;
*offset += 4; /* fill in later */
return *offset;
}
static void adjust_with_size(int seq_size, int seq_start,
uint8_t *buf, int *offset)
{
uint8_t seq_byte_size;
int orig_seq_size = seq_size;
int orig_seq_start = seq_start;
seq_size = *offset-seq_size;
seq_byte_size = set_gen_length(seq_size, buf, &seq_start);
if (seq_byte_size != 4)
{
memmove(&buf[orig_seq_start+seq_byte_size],
&buf[orig_seq_size], seq_size);
*offset -= 4-seq_byte_size;
}
}
static void gen_serial_number(uint8_t *buf, int *offset)
{
static const uint8_t ser_oid[] = { ASN1_INTEGER, 1, 0x7F };
memcpy(&buf[*offset], ser_oid , sizeof(ser_oid));
*offset += sizeof(ser_oid);
}
static void gen_signature_alg(uint8_t *buf, int *offset)
{
/* OBJECT IDENTIFIER sha1withRSAEncryption (1 2 840 113549 1 1 5) */
static const uint8_t sig_oid[] =
{
ASN1_SEQUENCE, 0x0d, ASN1_OID, 0x09,
0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x05,
ASN1_NULL, 0x00
};
memcpy(&buf[*offset], sig_oid, sizeof(sig_oid));
*offset += sizeof(sig_oid);
}
static int gen_dn(const char *name, uint8_t dn_type,
uint8_t *buf, int *offset)
{
int ret = X509_OK;
int name_size = strlen(name);
if (name_size > 0x70) /* just too big */
{
ret = X509_NOT_OK;
goto error;
}
buf[(*offset)++] = ASN1_SET;
set_gen_length(9+name_size, buf, offset);
buf[(*offset)++] = ASN1_SEQUENCE;
set_gen_length(7+name_size, buf, offset);
buf[(*offset)++] = ASN1_OID;
buf[(*offset)++] = 3;
buf[(*offset)++] = 0x55;
buf[(*offset)++] = 0x04;
buf[(*offset)++] = dn_type;
buf[(*offset)++] = ASN1_PRINTABLE_STR;
buf[(*offset)++] = name_size;
strcpy((char *)&buf[*offset], name);
*offset += name_size;
error:
return ret;
}
static int gen_issuer(const char * dn[], uint8_t *buf, int *offset)
{
int ret = X509_OK;
int seq_offset;
int seq_size = pre_adjust_with_size(
ASN1_SEQUENCE, &seq_offset, buf, offset);
char fqdn[128];
/* we need the common name, so if not configured, work out the fully
* qualified domain name */
if (dn[X509_COMMON_NAME] == NULL || strlen(dn[X509_COMMON_NAME]) == 0)
{
int fqdn_len;
gethostname(fqdn, sizeof(fqdn));
fqdn_len = strlen(fqdn);
fqdn[fqdn_len++] = '.';
if (getdomainname(&fqdn[fqdn_len], sizeof(fqdn)-fqdn_len) < 0)
{
ret = X509_NOT_OK;
goto error;
}
fqdn_len = strlen(fqdn);
if (fqdn[fqdn_len-1] == '.') /* ensure '.' is not last char */
fqdn[fqdn_len-1] = 0;
dn[X509_COMMON_NAME] = fqdn;
}
if ((ret = gen_dn(dn[X509_COMMON_NAME], 3, buf, offset)))
goto error;
if (dn[X509_ORGANIZATION] != NULL && strlen(dn[X509_ORGANIZATION]) > 0)
{
if ((ret = gen_dn(dn[X509_ORGANIZATION], 10, buf, offset)))
goto error;
}
if (dn[X509_ORGANIZATIONAL_UNIT] != NULL &&
strlen(dn[X509_ORGANIZATIONAL_UNIT]) > 0)
{
if ((ret = gen_dn(dn[X509_ORGANIZATIONAL_UNIT], 11, buf, offset)))
goto error;
}
adjust_with_size(seq_size, seq_offset, buf, offset);
error:
return ret;
}
static void gen_utc_time(uint8_t *buf, int *offset)
{
static const uint8_t time_seq[] =
{
ASN1_SEQUENCE, 30,
ASN1_UTC_TIME, 13,
'0', '7', '0', '1', '0', '1', '0', '0', '0', '0', '0', '0', 'Z',
ASN1_UTC_TIME, 13, /* make it good for 30 or so years */
'3', '8', '0', '1', '0', '1', '0', '0', '0', '0', '0', '0', 'Z'
};
/* fixed time */
memcpy(&buf[*offset], time_seq, sizeof(time_seq));
*offset += sizeof(time_seq);
}
static void gen_pub_key2(const RSA_CTX *rsa_ctx, uint8_t *buf, int *offset)
{
static const uint8_t pub_key_seq[] =
{
ASN1_INTEGER, 0x03, 0x01, 0x00, 0x01 /* INTEGER 65537 */
};
int seq_offset;
int pub_key_size = rsa_ctx->num_octets;
uint8_t *block = (uint8_t *)alloca(pub_key_size);
int seq_size = pre_adjust_with_size(
ASN1_SEQUENCE, &seq_offset, buf, offset);
buf[(*offset)++] = ASN1_INTEGER;
bi_export(rsa_ctx->bi_ctx, rsa_ctx->m, block, pub_key_size);
if (*block & 0x80) /* make integer positive */
{
set_gen_length(pub_key_size+1, buf, offset);
buf[(*offset)++] = 0;
}
else
set_gen_length(pub_key_size, buf, offset);
memcpy(&buf[*offset], block, pub_key_size);
*offset += pub_key_size;
memcpy(&buf[*offset], pub_key_seq, sizeof(pub_key_seq));
*offset += sizeof(pub_key_seq);
adjust_with_size(seq_size, seq_offset, buf, offset);
}
static void gen_pub_key1(const RSA_CTX *rsa_ctx, uint8_t *buf, int *offset)
{
int seq_offset;
int seq_size = pre_adjust_with_size(
ASN1_BIT_STRING, &seq_offset, buf, offset);
buf[(*offset)++] = 0; /* bit string is multiple of 8 */
gen_pub_key2(rsa_ctx, buf, offset);
adjust_with_size(seq_size, seq_offset, buf, offset);
}
static void gen_pub_key(const RSA_CTX *rsa_ctx, uint8_t *buf, int *offset)
{
/* OBJECT IDENTIFIER rsaEncryption (1 2 840 113549 1 1 1) */
static const uint8_t rsa_enc_oid[] =
{
ASN1_SEQUENCE, 0x0d, ASN1_OID, 0x09,
0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x01,
ASN1_NULL, 0x00
};
int seq_offset;
int seq_size = pre_adjust_with_size(
ASN1_SEQUENCE, &seq_offset, buf, offset);
memcpy(&buf[*offset], rsa_enc_oid, sizeof(rsa_enc_oid));
*offset += sizeof(rsa_enc_oid);
gen_pub_key1(rsa_ctx, buf, offset);
adjust_with_size(seq_size, seq_offset, buf, offset);
}
static void gen_signature(const RSA_CTX *rsa_ctx, const uint8_t *sha_dgst,
uint8_t *buf, int *offset)
{
static const uint8_t asn1_sig[] =
{
ASN1_SEQUENCE, 0x21, ASN1_SEQUENCE, 0x09, ASN1_OID, 0x05,
0x2b, 0x0e, 0x03, 0x02, 0x1a, /* sha1 (1 3 14 3 2 26) */
ASN1_NULL, 0x00, ASN1_OCTET_STRING, 0x14
};
uint8_t *enc_block = (uint8_t *)alloca(rsa_ctx->num_octets);
uint8_t *block = (uint8_t *)alloca(sizeof(asn1_sig) + SHA1_SIZE);
int sig_size;
/* add the digest as an embedded asn.1 sequence */
memcpy(block, asn1_sig, sizeof(asn1_sig));
memcpy(&block[sizeof(asn1_sig)], sha_dgst, SHA1_SIZE);
sig_size = RSA_encrypt(rsa_ctx, block,
sizeof(asn1_sig) + SHA1_SIZE, enc_block, 1);
buf[(*offset)++] = ASN1_BIT_STRING;
set_gen_length(sig_size+1, buf, offset);
buf[(*offset)++] = 0; /* bit string is multiple of 8 */
memcpy(&buf[*offset], enc_block, sig_size);
*offset += sig_size;
}
static int gen_tbs_cert(const char * dn[],
const RSA_CTX *rsa_ctx, uint8_t *buf, int *offset,
uint8_t *sha_dgst)
{
int ret = X509_OK;
SHA1_CTX sha_ctx;
int seq_offset;
int begin_tbs = *offset;
int seq_size = pre_adjust_with_size(
ASN1_SEQUENCE, &seq_offset, buf, offset);
gen_serial_number(buf, offset);
gen_signature_alg(buf, offset);
/* CA certicate issuer */
if ((ret = gen_issuer(dn, buf, offset)))
goto error;
gen_utc_time(buf, offset);
/* certificate issuer */
if ((ret = gen_issuer(dn, buf, offset)))
goto error;
gen_pub_key(rsa_ctx, buf, offset);
adjust_with_size(seq_size, seq_offset, buf, offset);
SHA1_Init(&sha_ctx);
SHA1_Update(&sha_ctx, &buf[begin_tbs], *offset-begin_tbs);
SHA1_Final(sha_dgst, &sha_ctx);
error:
return ret;
}
/**
* Create a new certificate.
*/
EXP_FUNC int STDCALL ssl_x509_create(SSL_CTX *ssl_ctx, uint32_t options, const char * dn[], uint8_t **cert_data)
{
int ret = X509_OK, offset = 0, seq_offset;
/* allocate enough space to load a new certificate */
uint8_t *buf = (uint8_t *)alloca(ssl_ctx->rsa_ctx->num_octets*2 + 512);
uint8_t sha_dgst[SHA1_SIZE];
int seq_size = pre_adjust_with_size(ASN1_SEQUENCE,
&seq_offset, buf, &offset);
if ((ret = gen_tbs_cert(dn, ssl_ctx->rsa_ctx, buf, &offset, sha_dgst)) < 0)
goto error;
gen_signature_alg(buf, &offset);
gen_signature(ssl_ctx->rsa_ctx, sha_dgst, buf, &offset);
adjust_with_size(seq_size, seq_offset, buf, &offset);
*cert_data = (uint8_t *)malloc(offset); /* create the exact memory for it */
memcpy(*cert_data, buf, offset);
error:
return ret < 0 ? ret : offset;
}
#endif