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-rw-r--r--Source/lib/asn1/der_decoder.c502
1 files changed, 502 insertions, 0 deletions
diff --git a/Source/lib/asn1/der_decoder.c b/Source/lib/asn1/der_decoder.c
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+/**
+ * @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 "der_decoder.h"
+
+#include <utils/allocator.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 = allocator_clone_chunk(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 = allocator_clone_chunk(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);
+ allocator_free(this);
+}
+
+/*
+ * Described in header.
+ */
+der_decoder_t *der_decoder_create(asn1_rule_t *rules)
+{
+ private_der_decoder_t *this = allocator_alloc_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);
+}
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