503 lines
10 KiB
C
503 lines
10 KiB
C
/**
|
|
* @file der_decoder.c
|
|
*
|
|
* @brief Implementation of der_decoder_t.
|
|
*/
|
|
|
|
/*
|
|
* Copyright (C) 2000-2004 Andreas Steffen
|
|
* Copyright (C) 2006 Martin Willi
|
|
* Hochschule fuer Technik Rapperswil
|
|
*
|
|
* Some parts taken over from pluto/asn1.c
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License as published by the
|
|
* Free Software Foundation; either version 2 of the License, or (at your
|
|
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
|
|
*
|
|
* This program 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 General Public License
|
|
* for more details.
|
|
*/
|
|
|
|
#include <gmp.h>
|
|
#include <string.h>
|
|
|
|
#include "der_decoder.h"
|
|
|
|
#include <daemon.h>
|
|
|
|
|
|
|
|
typedef struct private_der_decoder_t private_der_decoder_t;
|
|
|
|
/**
|
|
* Private data of a der_decoder_t object.
|
|
*/
|
|
struct private_der_decoder_t {
|
|
/**
|
|
* Public interface for this signer.
|
|
*/
|
|
der_decoder_t public;
|
|
|
|
/**
|
|
* Rule which was just processed
|
|
*/
|
|
asn1_rule_t *rule;
|
|
|
|
/**
|
|
* First rule of the whole ruleset
|
|
*/
|
|
asn1_rule_t *first_rule;
|
|
|
|
/**
|
|
* Output data struct
|
|
*/
|
|
void *output;
|
|
|
|
/**
|
|
* Complex things like this need a logger ;-)
|
|
*/
|
|
logger_t *logger;
|
|
};
|
|
|
|
status_t read_hdr(private_der_decoder_t *this, chunk_t *data);
|
|
|
|
/**
|
|
* Read a sequence from data, parse its contents recursivly
|
|
*/
|
|
status_t read_sequence(private_der_decoder_t *this, chunk_t data)
|
|
{
|
|
status_t status;
|
|
asn1_rule_t *next_rule;
|
|
|
|
while(TRUE)
|
|
{
|
|
next_rule = this->rule + 1;
|
|
if (next_rule->type == ASN1_END)
|
|
{
|
|
this->rule++;
|
|
break;
|
|
}
|
|
status = read_hdr(this, &data);
|
|
if (status != SUCCESS)
|
|
{
|
|
return status;
|
|
}
|
|
}
|
|
|
|
this->logger->log(this->logger, CONTROL|LEVEL2, "Sequence end");
|
|
return SUCCESS;
|
|
}
|
|
|
|
/**
|
|
* Read choice of data, parse if one of the choosable types arise
|
|
*/
|
|
status_t read_choice(private_der_decoder_t *this, chunk_t *data)
|
|
{
|
|
status_t status = PARSE_ERROR;
|
|
asn1_rule_t *next_rule;
|
|
bool found = FALSE;
|
|
|
|
this->logger->log_chunk(this->logger, CONTROL|LEVEL2, "Choice data", *data);
|
|
|
|
while(TRUE)
|
|
{
|
|
next_rule = this->rule + 1;
|
|
if (next_rule->type == ASN1_END)
|
|
{
|
|
this->rule++;
|
|
return status;
|
|
}
|
|
if (!found && *(data->ptr) == next_rule->type)
|
|
{
|
|
found = TRUE;
|
|
status = read_hdr(this, data);
|
|
}
|
|
else
|
|
{
|
|
this->rule++;
|
|
}
|
|
}
|
|
this->logger->log(this->logger, CONTROL|LEVEL2, "Choice end");
|
|
return status;
|
|
}
|
|
|
|
/**
|
|
* Read a utc or generalized time
|
|
*/
|
|
status_t read_time(private_der_decoder_t *this, chunk_t data)
|
|
{
|
|
struct tm t;
|
|
time_t tz_offset;
|
|
u_char *eot = NULL;
|
|
const char* format;
|
|
time_t *result = (time_t*)((u_int8_t*)this->output + this->rule->data_offset);
|
|
|
|
/* TODO: Test it */
|
|
this->logger->log_chunk(this->logger, CONTROL|LEVEL2, "TIME", data);
|
|
|
|
if ((eot = memchr(data.ptr, 'Z', data.len)) != NULL)
|
|
{
|
|
/* Zulu time with a zero time zone offset */
|
|
tz_offset = 0;
|
|
}
|
|
else if ((eot = memchr(data.ptr, '+', data.len)) != NULL)
|
|
{
|
|
int tz_hour, tz_min;
|
|
|
|
sscanf(eot+1, "%2d%2d", &tz_hour, &tz_min);
|
|
/* positive time zone offset */
|
|
tz_offset = 3600*tz_hour + 60*tz_min;
|
|
}
|
|
else if ((eot = memchr(data.ptr, '-', data.len)) != NULL)
|
|
{
|
|
int tz_hour, tz_min;
|
|
|
|
sscanf(eot+1, "%2d%2d", &tz_hour, &tz_min);
|
|
/* negative time zone offset */
|
|
tz_offset = -3600*tz_hour - 60*tz_min;
|
|
}
|
|
else
|
|
{
|
|
/* error in time format */
|
|
return PARSE_ERROR;
|
|
}
|
|
|
|
if (this->rule->type == ASN1_UTCTIME)
|
|
{
|
|
format = "%2d%2d%2d%2d%2d";
|
|
}
|
|
else
|
|
{
|
|
format = "%4d%2d%2d%2d%2d";
|
|
}
|
|
|
|
sscanf(data.ptr, format, &t.tm_year, &t.tm_mon, &t.tm_mday, &t.tm_hour, &t.tm_min);
|
|
|
|
/* is there a seconds field? */
|
|
if ((eot - data.ptr) == ((this->rule->type == ASN1_UTCTIME)?12:14))
|
|
{
|
|
sscanf(eot-2, "%2d", &t.tm_sec);
|
|
}
|
|
else
|
|
{
|
|
t.tm_sec = 0;
|
|
}
|
|
|
|
/* representation of year */
|
|
if (t.tm_year >= 1900)
|
|
{
|
|
t.tm_year -= 1900;
|
|
}
|
|
else if (t.tm_year >= 100)
|
|
{
|
|
return PARSE_ERROR;
|
|
}
|
|
else if (t.tm_year < 50)
|
|
{
|
|
t.tm_year += 100;
|
|
}
|
|
|
|
/* representation of month 0..11*/
|
|
t.tm_mon--;
|
|
|
|
/* set daylight saving time to off */
|
|
t.tm_isdst = 0;
|
|
|
|
/* compensate timezone */
|
|
|
|
*result = mktime(&t) - timezone - tz_offset;
|
|
return SUCCESS;
|
|
}
|
|
|
|
/**
|
|
* Read an integer as u_int or as mpz_t
|
|
*/
|
|
status_t read_int(private_der_decoder_t *this, chunk_t data)
|
|
{
|
|
this->logger->log_chunk(this->logger, CONTROL|LEVEL2, "ASN1_INTEGER", data);
|
|
|
|
if (this->rule->flags & ASN1_MPZ)
|
|
{
|
|
mpz_t *mpz = (mpz_t*)((u_int8_t*)this->output + this->rule->data_offset);
|
|
mpz_import(*mpz, data.len, 1, 1, 1, 0, data.ptr);
|
|
}
|
|
else
|
|
{
|
|
u_int *integ = (u_int*)((u_int8_t*)this->output + this->rule->data_offset);
|
|
|
|
*integ = 0;
|
|
while (data.len-- > 0)
|
|
{
|
|
*integ = 256 * (*integ) + *data.ptr++;
|
|
}
|
|
}
|
|
return SUCCESS;
|
|
}
|
|
|
|
/**
|
|
* Read boolean value
|
|
*/
|
|
status_t read_bool(private_der_decoder_t *this, chunk_t data)
|
|
{
|
|
this->logger->log_chunk(this->logger, CONTROL|LEVEL2, "ASN1_BOOLEAN", data);
|
|
|
|
bool *boolean = (u_int*)((u_int8_t*)this->output + this->rule->data_offset);
|
|
|
|
*boolean = *data.ptr;
|
|
|
|
return SUCCESS;
|
|
}
|
|
|
|
/**
|
|
* Read an OID
|
|
*/
|
|
status_t read_oid(private_der_decoder_t *this, chunk_t data)
|
|
{
|
|
this->logger->log_chunk(this->logger, CONTROL|LEVEL2, "ASN1_OID", data);
|
|
/* TODO: OID parsing stuff */
|
|
return SUCCESS;
|
|
}
|
|
|
|
/**
|
|
* Read a bitstring
|
|
*/
|
|
status_t read_bitstring(private_der_decoder_t *this, chunk_t data)
|
|
{
|
|
/* TODO: cleanly determine amount of unused bits */
|
|
|
|
/* skip "unused-bits-in-following-byte"-byte */
|
|
data.ptr += 1;
|
|
data.len -= 1;
|
|
|
|
if (data.len < 1)
|
|
{
|
|
return FAILED;
|
|
}
|
|
|
|
chunk_t *chunk = (chunk_t*)((u_int8_t*)this->output + this->rule->data_offset);
|
|
|
|
*chunk = chunk_clone(data);
|
|
|
|
this->logger->log_chunk(this->logger, CONTROL|LEVEL2, "ASN1_BITSTRING", data);
|
|
return SUCCESS;
|
|
}
|
|
|
|
/**
|
|
* Read any type which appears in a chunk
|
|
*/
|
|
status_t read_any(private_der_decoder_t *this, chunk_t data)
|
|
{
|
|
chunk_t *chunk = (chunk_t*)((u_int8_t*)this->output + this->rule->data_offset);
|
|
|
|
*chunk = chunk_clone(data);
|
|
|
|
this->logger->log_chunk(this->logger, CONTROL|LEVEL2, "ASN1_ANY", data);
|
|
return SUCCESS;
|
|
}
|
|
|
|
/**
|
|
* Read the length field of a type
|
|
*/
|
|
u_int32_t read_length(chunk_t *data)
|
|
{
|
|
u_int8_t n;
|
|
size_t len;
|
|
|
|
if (data->len < 1)
|
|
{
|
|
return -1;
|
|
}
|
|
|
|
/* read first octet of length field */
|
|
n = *data->ptr;
|
|
data->ptr++; data->len--;
|
|
|
|
if ((n & 0x80) == 0)
|
|
{
|
|
/* single length octet */
|
|
return n;
|
|
}
|
|
|
|
/* composite length, determine number of length octets */
|
|
n &= 0x7f;
|
|
|
|
if (n > data->len)
|
|
{
|
|
/* length longer than available bytes */
|
|
return -1;
|
|
}
|
|
|
|
if (n > sizeof(len))
|
|
{
|
|
/* larger than size_t can hold */
|
|
return -1;
|
|
}
|
|
|
|
len = 0;
|
|
while (n-- > 0)
|
|
{
|
|
len = 256 * len + *data->ptr;
|
|
data->ptr++; data->len--;
|
|
}
|
|
return len;
|
|
}
|
|
|
|
/**
|
|
* Read the next field
|
|
*/
|
|
status_t read_hdr(private_der_decoder_t *this, chunk_t *data)
|
|
{
|
|
chunk_t inner;
|
|
/* TODO: Redo this that an average mid-european can understand it */
|
|
|
|
beginning:
|
|
/* advance to the next rule */
|
|
this->rule++;
|
|
|
|
this->logger->log(this->logger, CONTROL|LEVEL2, "reading rule %d %s",
|
|
this->rule - this->first_rule,
|
|
mapping_find(asn1_type_m, this->rule->type));
|
|
|
|
switch (this->rule->type)
|
|
{
|
|
case ASN1_END:
|
|
/* ignore, handled outside */
|
|
return SUCCESS;
|
|
case ASN1_CHOICE:
|
|
/* CHOICE has no type/length */
|
|
break;
|
|
default:
|
|
/* anything else has type/length */
|
|
if (data->len == 0)
|
|
{
|
|
goto beginning;
|
|
}
|
|
this->logger->log_chunk(this->logger, CONTROL|LEVEL3, "reading from:", *data);
|
|
|
|
/* read type, advance in data */
|
|
if (this->rule->type != ASN1_ANY && *(data->ptr) != this->rule->type)
|
|
{
|
|
if (this->rule->flags & ASN1_OPTIONAL)
|
|
{
|
|
goto beginning;
|
|
}
|
|
if (this->rule->flags & ASN1_DEFAULT)
|
|
{
|
|
goto beginning;
|
|
}
|
|
this->logger->log(this->logger, CONTROL|LEVEL2, "Bad byte found: %x, %x expected",
|
|
*data->ptr, this->rule->type);
|
|
return PARSE_ERROR;
|
|
}
|
|
data->ptr++;
|
|
data->len--;
|
|
|
|
/* read length, advance in data */
|
|
inner.len = read_length(data);
|
|
if (inner.len == -1)
|
|
{
|
|
this->logger->log(this->logger, CONTROL|LEVEL2, "Error reading length");
|
|
return PARSE_ERROR;
|
|
}
|
|
this->logger->log(this->logger, CONTROL|LEVEL2, "Length is %d", inner.len);
|
|
inner.ptr = data->ptr;
|
|
|
|
/* advance in data, at the size of the inner */
|
|
data->ptr += inner.len;
|
|
data->len -= inner.len;
|
|
}
|
|
|
|
/* process inner */
|
|
while (TRUE)
|
|
{
|
|
switch (this->rule->type)
|
|
{
|
|
case ASN1_INTEGER:
|
|
return read_int(this, inner);
|
|
case ASN1_BOOLEAN:
|
|
return read_bool(this, inner);
|
|
case ASN1_SEQUENCE:
|
|
case ASN1_SET:
|
|
return read_sequence(this, inner);
|
|
case ASN1_TAG_E_0:
|
|
case ASN1_TAG_E_1:
|
|
case ASN1_TAG_E_2:
|
|
case ASN1_TAG_E_3:
|
|
case ASN1_TAG_E_4:
|
|
case ASN1_TAG_E_5:
|
|
case ASN1_TAG_E_6:
|
|
case ASN1_TAG_E_7:
|
|
return read_hdr(this, &inner);
|
|
case ASN1_TAG_I_0:
|
|
case ASN1_TAG_I_1:
|
|
case ASN1_TAG_I_2:
|
|
case ASN1_TAG_I_3:
|
|
case ASN1_TAG_I_4:
|
|
case ASN1_TAG_I_5:
|
|
case ASN1_TAG_I_6:
|
|
case ASN1_TAG_I_7:
|
|
this->rule++;
|
|
continue;
|
|
case ASN1_OID:
|
|
return read_oid(this, inner);
|
|
case ASN1_CHOICE:
|
|
return read_choice(this, data);
|
|
case ASN1_NULL:
|
|
return SUCCESS;
|
|
case ASN1_ANY:
|
|
return read_any(this, inner);
|
|
case ASN1_UTCTIME:
|
|
return read_time(this, inner);
|
|
case ASN1_GENERALIZEDTIME:
|
|
return read_time(this, inner);
|
|
case ASN1_BITSTRING:
|
|
return read_bitstring(this, inner);
|
|
case ASN1_OCTETSTRING:
|
|
return read_any(this, inner);
|
|
default:
|
|
return NOT_SUPPORTED;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Implements der_decoder_t.decode
|
|
*/
|
|
status_t decode(private_der_decoder_t *this, chunk_t input, void *output)
|
|
{
|
|
this->rule = this->first_rule - 1;
|
|
this->output = output;
|
|
/* start parsing recursivly */
|
|
return read_hdr(this, &input);
|
|
}
|
|
|
|
/**
|
|
* Implementation of der_decoder.destroy.
|
|
*/
|
|
static void destroy(private_der_decoder_t *this)
|
|
{
|
|
this->logger->destroy(this->logger);
|
|
free(this);
|
|
}
|
|
|
|
/*
|
|
* Described in header.
|
|
*/
|
|
der_decoder_t *der_decoder_create(asn1_rule_t *rules)
|
|
{
|
|
private_der_decoder_t *this = malloc_thing(private_der_decoder_t);
|
|
|
|
/* public functions */
|
|
this->public.decode = (status_t (*) (der_decoder_t*,chunk_t,void*))decode;
|
|
this->public.destroy = (void (*) (der_decoder_t*))destroy;
|
|
|
|
this->first_rule = rules;
|
|
this->logger = logger_create("[DERDC]", CONTROL, FALSE, NULL);
|
|
|
|
return &(this->public);
|
|
}
|