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esp8266/ssl/asn1.c
cameronrich f9ee197cff dir changes - things are broken at the moment
git-svn-id: svn://svn.code.sf.net/p/axtls/code/trunk@116 9a5d90b5-6617-0410-8a86-bb477d3ed2e3
2007-08-29 09:15:39 +00:00

461 lines
11 KiB
C

/*
* Copyright(C) 2006 Cameron Rich
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/**
* @file asn1.c
*
* Some primitive asn methods for extraction ASN.1 data.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "os_port.h"
#include "crypto.h"
#include "crypto_misc.h"
#define SIG_OID_PREFIX_SIZE 8
/* Must be an RSA algorithm with either SHA1 or MD5 for verifying to work */
static const uint8_t sig_oid_prefix[SIG_OID_PREFIX_SIZE] =
{
0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01
};
/* CN, O, OU */
static const uint8_t g_dn_types[] = { 3, 10, 11 };
int get_asn1_length(const uint8_t *buf, int *offset)
{
int len, i;
if (!(buf[*offset] & 0x80)) /* short form */
{
len = buf[(*offset)++];
}
else /* long form */
{
int length_bytes = buf[(*offset)++]&0x7f;
len = 0;
for (i = 0; i < length_bytes; i++)
{
len <<= 8;
len += buf[(*offset)++];
}
}
return len;
}
/**
* Skip the ASN1.1 object type and its length. Get ready to read the object's
* data.
*/
int asn1_next_obj(const uint8_t *buf, int *offset, int obj_type)
{
if (buf[*offset] != obj_type)
return X509_NOT_OK;
(*offset)++;
return get_asn1_length(buf, offset);
}
/**
* Skip over an ASN.1 object type completely. Get ready to read the next
* object.
*/
int asn1_skip_obj(const uint8_t *buf, int *offset, int obj_type)
{
int len;
if (buf[*offset] != obj_type)
return X509_NOT_OK;
(*offset)++;
len = get_asn1_length(buf, offset);
*offset += len;
return 0;
}
/**
* Read an integer value for ASN.1 data
* Note: This function allocates memory which must be freed by the user.
*/
int asn1_get_int(const uint8_t *buf, int *offset, uint8_t **object)
{
int len;
if ((len = asn1_next_obj(buf, offset, ASN1_INTEGER)) < 0)
goto end_int_array;
*object = (uint8_t *)malloc(len);
memcpy(*object, &buf[*offset], len);
*offset += len;
end_int_array:
return len;
}
/**
* Get all the RSA private key specifics from an ASN.1 encoded file
*/
int asn1_get_private_key(const uint8_t *buf, int len, RSA_CTX **rsa_ctx)
{
int offset = 7;
uint8_t *modulus, *priv_exp, *pub_exp;
int mod_len, priv_len, pub_len;
#ifdef CONFIG_BIGINT_CRT
uint8_t *p, *q, *dP, *dQ, *qInv;
int p_len, q_len, dP_len, dQ_len, qInv_len;
#endif
/* not in der format */
if (buf[0] != ASN1_SEQUENCE) /* basic sanity check */
{
#ifdef CONFIG_SSL_FULL_MODE
printf("Error: This is not a valid ASN.1 file\n");
#endif
return X509_INVALID_PRIV_KEY;
}
/* initialise the RNG */
RNG_initialize(buf, len);
mod_len = asn1_get_int(buf, &offset, &modulus);
pub_len = asn1_get_int(buf, &offset, &pub_exp);
priv_len = asn1_get_int(buf, &offset, &priv_exp);
if (mod_len <= 0 || pub_len <= 0 || priv_len <= 0)
return X509_INVALID_PRIV_KEY;
#ifdef CONFIG_BIGINT_CRT
p_len = asn1_get_int(buf, &offset, &p);
q_len = asn1_get_int(buf, &offset, &q);
dP_len = asn1_get_int(buf, &offset, &dP);
dQ_len = asn1_get_int(buf, &offset, &dQ);
qInv_len = asn1_get_int(buf, &offset, &qInv);
if (p_len <= 0 || q_len <= 0 || dP_len <= 0 || dQ_len <= 0 || qInv_len <= 0)
return X509_INVALID_PRIV_KEY;
RSA_priv_key_new(rsa_ctx,
modulus, mod_len, pub_exp, pub_len, priv_exp, priv_len,
p, p_len, q, p_len, dP, dP_len, dQ, dQ_len, qInv, qInv_len);
free(p);
free(q);
free(dP);
free(dQ);
free(qInv);
#else
RSA_priv_key_new(rsa_ctx,
modulus, mod_len, pub_exp, pub_len, priv_exp, priv_len);
#endif
free(modulus);
free(priv_exp);
free(pub_exp);
return X509_OK;
}
/**
* Get the time of a certificate. Ignore hours/minutes/seconds.
*/
static int asn1_get_utc_time(const uint8_t *buf, int *offset, time_t *t)
{
int ret = X509_NOT_OK, len, t_offset;
struct tm tm;
if (buf[(*offset)++] != ASN1_UTC_TIME)
goto end_utc_time;
len = get_asn1_length(buf, offset);
t_offset = *offset;
memset(&tm, 0, sizeof(struct tm));
tm.tm_year = (buf[t_offset] - '0')*10 + (buf[t_offset+1] - '0');
if (tm.tm_year <= 50) /* 1951-2050 thing */
{
tm.tm_year += 100;
}
tm.tm_mon = (buf[t_offset+2] - '0')*10 + (buf[t_offset+3] - '0') - 1;
tm.tm_mday = (buf[t_offset+4] - '0')*10 + (buf[t_offset+5] - '0');
*t = mktime(&tm);
*offset += len;
ret = X509_OK;
end_utc_time:
return ret;
}
/**
* Get the version type of a certificate (which we don't actually care about)
*/
int asn1_version(const uint8_t *cert, int *offset, X509_CTX *x509_ctx)
{
int ret = X509_NOT_OK;
(*offset) += 2; /* get past explicit tag */
if (asn1_skip_obj(cert, offset, ASN1_INTEGER))
goto end_version;
ret = X509_OK;
end_version:
return ret;
}
/**
* Retrieve the notbefore and notafter certificate times.
*/
int asn1_validity(const uint8_t *cert, int *offset, X509_CTX *x509_ctx)
{
return (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0 ||
asn1_get_utc_time(cert, offset, &x509_ctx->not_before) ||
asn1_get_utc_time(cert, offset, &x509_ctx->not_after));
}
/**
* Get the components of a distinguished name
*/
static int asn1_get_oid_x520(const uint8_t *buf, int *offset)
{
int dn_type = 0;
int len;
if ((len = asn1_next_obj(buf, offset, ASN1_OID)) < 0)
goto end_oid;
/* expect a sequence of 2.5.4.[x] where x is a one of distinguished name
components we are interested in. */
if (len == 3 && buf[(*offset)++] == 0x55 && buf[(*offset)++] == 0x04)
dn_type = buf[(*offset)++];
else
{
*offset += len; /* skip over it */
}
end_oid:
return dn_type;
}
/**
* Obtain an ASN.1 printable string type.
*/
static int asn1_get_printable_str(const uint8_t *buf, int *offset, char **str)
{
int len = X509_NOT_OK;
/* some certs have this awful crud in them for some reason */
if (buf[*offset] != ASN1_PRINTABLE_STR &&
buf[*offset] != ASN1_TELETEX_STR && buf[*offset] != ASN1_IA5_STR)
goto end_pnt_str;
(*offset)++;
len = get_asn1_length(buf, offset);
*str = (char *)malloc(len+1); /* allow for null */
memcpy(*str, &buf[*offset], len);
(*str)[len] = 0; /* null terminate */
*offset += len;
end_pnt_str:
return len;
}
/**
* Get the subject name (or the issuer) of a certificate.
*/
int asn1_name(const uint8_t *cert, int *offset, char *dn[])
{
int ret = X509_NOT_OK;
int dn_type;
char *tmp = NULL;
if (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0)
goto end_name;
while (asn1_next_obj(cert, offset, ASN1_SET) >= 0)
{
int i, found = 0;
if (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0 ||
(dn_type = asn1_get_oid_x520(cert, offset)) < 0)
goto end_name;
if (asn1_get_printable_str(cert, offset, &tmp) < 0)
{
free(tmp);
goto end_name;
}
/* find the distinguished named type */
for (i = 0; i < X509_NUM_DN_TYPES; i++)
{
if (dn_type == g_dn_types[i])
{
if (dn[i] == NULL)
{
dn[i] = tmp;
found = 1;
break;
}
}
}
if (found == 0) /* not found so get rid of it */
{
free(tmp);
}
}
ret = X509_OK;
end_name:
return ret;
}
/**
* Read the modulus and public exponent of a certificate.
*/
int asn1_public_key(const uint8_t *cert, int *offset, X509_CTX *x509_ctx)
{
int ret = X509_NOT_OK, mod_len, pub_len;
uint8_t *modulus, *pub_exp;
if (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0 ||
asn1_skip_obj(cert, offset, ASN1_SEQUENCE) ||
asn1_next_obj(cert, offset, ASN1_BIT_STRING) < 0)
goto end_pub_key;
(*offset)++;
if (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0)
goto end_pub_key;
mod_len = asn1_get_int(cert, offset, &modulus);
pub_len = asn1_get_int(cert, offset, &pub_exp);
RSA_pub_key_new(&x509_ctx->rsa_ctx, modulus, mod_len, pub_exp, pub_len);
free(modulus);
free(pub_exp);
ret = X509_OK;
end_pub_key:
return ret;
}
#ifdef CONFIG_SSL_CERT_VERIFICATION
/**
* Read the signature of the certificate.
*/
int asn1_signature(const uint8_t *cert, int *offset, X509_CTX *x509_ctx)
{
int ret = X509_NOT_OK;
if (cert[(*offset)++] != ASN1_BIT_STRING)
goto end_sig;
x509_ctx->sig_len = get_asn1_length(cert, offset);
x509_ctx->signature = (uint8_t *)malloc(x509_ctx->sig_len);
memcpy(x509_ctx->signature, &cert[*offset], x509_ctx->sig_len);
*offset += x509_ctx->sig_len;
ret = X509_OK;
end_sig:
return ret;
}
/*
* Compare 2 distinguished name components for equality
* @return 0 if a match
*/
static int asn1_compare_dn_comp(const char *dn1, const char *dn2)
{
int ret = 1;
if ((dn1 && dn2 == NULL) || (dn1 == NULL && dn2)) goto err_no_match;
ret = (dn1 && dn2) ? strcmp(dn1, dn2) : 0;
err_no_match:
return ret;
}
/**
* Clean up all of the CA certificates.
*/
void remove_ca_certs(CA_CERT_CTX *ca_cert_ctx)
{
int i = 0;
while (i < CONFIG_X509_MAX_CA_CERTS && ca_cert_ctx->cert[i])
{
x509_free(ca_cert_ctx->cert[i]);
ca_cert_ctx->cert[i++] = NULL;
}
free(ca_cert_ctx);
}
/*
* Compare 2 distinguished names for equality
* @return 0 if a match
*/
int asn1_compare_dn(char * const dn1[], char * const dn2[])
{
int i;
for (i = 0; i < X509_NUM_DN_TYPES; i++)
{
if (asn1_compare_dn_comp(dn1[i], dn2[i]))
{
return 1;
}
}
return 0; /* all good */
}
#endif
/**
* Read the signature type of the certificate. We only support RSA-MD5 and
* RSA-SHA1 signature types.
*/
int asn1_signature_type(const uint8_t *cert,
int *offset, X509_CTX *x509_ctx)
{
int ret = X509_NOT_OK, len;
if (cert[(*offset)++] != ASN1_OID)
goto end_check_sig;
len = get_asn1_length(cert, offset);
if (memcmp(sig_oid_prefix, &cert[*offset], SIG_OID_PREFIX_SIZE))
goto end_check_sig; /* unrecognised cert type */
x509_ctx->sig_type = cert[*offset + SIG_OID_PREFIX_SIZE];
*offset += len;
asn1_skip_obj(cert, offset, ASN1_NULL); /* if it's there */
ret = X509_OK;
end_check_sig:
return ret;
}