This commit is contained in:
Martin Willi
@@ -0,0 +1,770 @@
|
||||
/* Simple ASN.1 parser
|
||||
* Copyright (C) 2000-2004 Andreas Steffen, Zuercher Hochschule Winterthur
|
||||
*
|
||||
* 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.
|
||||
*
|
||||
* RCSID $Id: asn1.c,v 1.16 2006/01/04 21:00:43 as Exp $
|
||||
*/
|
||||
|
||||
#include <stdlib.h>
|
||||
#include <string.h>
|
||||
#include <time.h>
|
||||
|
||||
#include <freeswan.h>
|
||||
|
||||
#include "constants.h"
|
||||
#include "defs.h"
|
||||
#include "mp_defs.h"
|
||||
#include "asn1.h"
|
||||
#include "oid.h"
|
||||
#include "log.h"
|
||||
|
||||
/* some common prefabricated ASN.1 constants */
|
||||
|
||||
static u_char ASN1_INTEGER_0_str[] = { 0x02, 0x00 };
|
||||
static u_char ASN1_INTEGER_1_str[] = { 0x02, 0x01, 0x01 };
|
||||
static u_char ASN1_INTEGER_2_str[] = { 0x02, 0x01, 0x02 };
|
||||
|
||||
const chunk_t ASN1_INTEGER_0 = strchunk(ASN1_INTEGER_0_str);
|
||||
const chunk_t ASN1_INTEGER_1 = strchunk(ASN1_INTEGER_1_str);
|
||||
const chunk_t ASN1_INTEGER_2 = strchunk(ASN1_INTEGER_2_str);
|
||||
|
||||
/* some popular algorithmIdentifiers */
|
||||
|
||||
static u_char ASN1_md5_id_str[] = {
|
||||
0x30, 0x0C,
|
||||
0x06, 0x08, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x02, 0x05,
|
||||
0x05, 0x00
|
||||
};
|
||||
|
||||
static u_char ASN1_sha1_id_str[] = {
|
||||
0x30, 0x09,
|
||||
0x06, 0x05, 0x2B, 0x0E,0x03, 0x02, 0x1A,
|
||||
0x05, 0x00
|
||||
};
|
||||
|
||||
static u_char ASN1_md5WithRSA_id_str[] = {
|
||||
0x30, 0x0D,
|
||||
0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x04,
|
||||
0x05, 0x00
|
||||
};
|
||||
|
||||
static u_char ASN1_sha1WithRSA_id_str[] = {
|
||||
0x30, 0x0D,
|
||||
0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x05,
|
||||
0x05, 0x00
|
||||
};
|
||||
|
||||
static u_char ASN1_rsaEncryption_id_str[] = {
|
||||
0x30, 0x0D,
|
||||
0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01,
|
||||
0x05, 0x00
|
||||
};
|
||||
|
||||
const chunk_t ASN1_md5_id = strchunk(ASN1_md5_id_str);
|
||||
const chunk_t ASN1_sha1_id = strchunk(ASN1_sha1_id_str);
|
||||
const chunk_t ASN1_rsaEncryption_id = strchunk(ASN1_rsaEncryption_id_str);
|
||||
const chunk_t ASN1_md5WithRSA_id = strchunk(ASN1_md5WithRSA_id_str);
|
||||
const chunk_t ASN1_sha1WithRSA_id = strchunk(ASN1_sha1WithRSA_id_str);
|
||||
|
||||
/* ASN.1 definiton of an algorithmIdentifier */
|
||||
|
||||
static const asn1Object_t algorithmIdentifierObjects[] = {
|
||||
{ 0, "algorithmIdentifier", ASN1_SEQUENCE, ASN1_NONE }, /* 0 */
|
||||
{ 1, "algorithm", ASN1_OID, ASN1_BODY }, /* 1 */
|
||||
{ 1, "parameters", ASN1_EOC, ASN1_RAW } /* 2 */
|
||||
};
|
||||
|
||||
#define ALGORITHM_ID_ALG 1
|
||||
#define ALGORITHM_ID_PARAMETERS 2
|
||||
#define ALGORITHM_ID_ROOF 3
|
||||
|
||||
/*
|
||||
* return the ASN.1 encoded algorithm identifier
|
||||
*/
|
||||
chunk_t
|
||||
asn1_algorithmIdentifier(int oid)
|
||||
{
|
||||
switch (oid)
|
||||
{
|
||||
case OID_RSA_ENCRYPTION:
|
||||
return ASN1_rsaEncryption_id;
|
||||
case OID_MD5_WITH_RSA:
|
||||
return ASN1_md5WithRSA_id;
|
||||
case OID_SHA1_WITH_RSA:
|
||||
return ASN1_sha1WithRSA_id;
|
||||
case OID_MD5:
|
||||
return ASN1_md5_id;
|
||||
case OID_SHA1:
|
||||
return ASN1_sha1_id;
|
||||
default:
|
||||
return empty_chunk;
|
||||
}
|
||||
}
|
||||
|
||||
/* If the oid is listed in the oid_names table then the corresponding
|
||||
* position in the oid_names table is returned otherwise -1 is returned
|
||||
*/
|
||||
int
|
||||
known_oid(chunk_t object)
|
||||
{
|
||||
int oid = 0;
|
||||
|
||||
while (object.len)
|
||||
{
|
||||
if (oid_names[oid].octet == *object.ptr)
|
||||
{
|
||||
if (--object.len == 0 || oid_names[oid].down == 0)
|
||||
{
|
||||
return oid; /* found terminal symbol */
|
||||
}
|
||||
else
|
||||
{
|
||||
object.ptr++; oid++; /* advance to next hex octet */
|
||||
}
|
||||
}
|
||||
else
|
||||
{
|
||||
if (oid_names[oid].next)
|
||||
oid = oid_names[oid].next;
|
||||
else
|
||||
return OID_UNKNOWN;
|
||||
}
|
||||
}
|
||||
return -1;
|
||||
}
|
||||
|
||||
/*
|
||||
* Decodes the length in bytes of an ASN.1 object
|
||||
*/
|
||||
u_int
|
||||
asn1_length(chunk_t *blob)
|
||||
{
|
||||
u_char n;
|
||||
size_t len;
|
||||
|
||||
/* advance from tag field on to length field */
|
||||
blob->ptr++;
|
||||
blob->len--;
|
||||
|
||||
/* read first octet of length field */
|
||||
n = *blob->ptr++;
|
||||
blob->len--;
|
||||
|
||||
if ((n & 0x80) == 0) /* single length octet */
|
||||
return n;
|
||||
|
||||
/* composite length, determine number of length octets */
|
||||
n &= 0x7f;
|
||||
|
||||
if (n > blob->len)
|
||||
{
|
||||
DBG(DBG_PARSING,
|
||||
DBG_log("number of length octets is larger than ASN.1 object")
|
||||
)
|
||||
return ASN1_INVALID_LENGTH;
|
||||
}
|
||||
|
||||
if (n > sizeof(len))
|
||||
{
|
||||
DBG(DBG_PARSING,
|
||||
DBG_log("number of length octets is larger than limit of %d octets"
|
||||
, (int)sizeof(len))
|
||||
)
|
||||
return ASN1_INVALID_LENGTH;
|
||||
}
|
||||
|
||||
len = 0;
|
||||
|
||||
while (n-- > 0)
|
||||
{
|
||||
len = 256*len + *blob->ptr++;
|
||||
blob->len--;
|
||||
}
|
||||
return len;
|
||||
}
|
||||
|
||||
/*
|
||||
* codes ASN.1 lengths up to a size of 16'777'215 bytes
|
||||
*/
|
||||
void
|
||||
code_asn1_length(size_t length, chunk_t *code)
|
||||
{
|
||||
if (length < 128)
|
||||
{
|
||||
code->ptr[0] = length;
|
||||
code->len = 1;
|
||||
}
|
||||
else if (length < 256)
|
||||
{
|
||||
code->ptr[0] = 0x81;
|
||||
code->ptr[1] = (u_char) length;
|
||||
code->len = 2;
|
||||
}
|
||||
else if (length < 65536)
|
||||
{
|
||||
code->ptr[0] = 0x82;
|
||||
code->ptr[1] = length >> 8;
|
||||
code->ptr[2] = length & 0x00ff;
|
||||
code->len = 3;
|
||||
}
|
||||
else
|
||||
{
|
||||
code->ptr[0] = 0x83;
|
||||
code->ptr[1] = length >> 16;
|
||||
code->ptr[2] = (length >> 8) & 0x00ff;
|
||||
code->ptr[3] = length & 0x0000ff;
|
||||
code->len = 4;
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* build an empty asn.1 object with tag and length fields already filled in
|
||||
*/
|
||||
u_char*
|
||||
build_asn1_object(chunk_t *object, asn1_t type, size_t datalen)
|
||||
{
|
||||
u_char length_buf[4];
|
||||
chunk_t length = { length_buf, 0 };
|
||||
u_char *pos;
|
||||
|
||||
/* code the asn.1 length field */
|
||||
code_asn1_length(datalen, &length);
|
||||
|
||||
/* allocate memory for the asn.1 TLV object */
|
||||
object->len = 1 + length.len + datalen;
|
||||
object->ptr = alloc_bytes(object->len, "asn1 object");
|
||||
|
||||
/* set position pointer at the start of the object */
|
||||
pos = object->ptr;
|
||||
|
||||
/* copy the asn.1 tag field and advance the pointer */
|
||||
*pos++ = type;
|
||||
|
||||
/* copy the asn.1 length field and advance the pointer */
|
||||
chunkcpy(pos, length);
|
||||
|
||||
return pos;
|
||||
}
|
||||
|
||||
/*
|
||||
* build a simple ASN.1 object
|
||||
*/
|
||||
chunk_t
|
||||
asn1_simple_object(asn1_t tag, chunk_t content)
|
||||
{
|
||||
chunk_t object;
|
||||
|
||||
u_char *pos = build_asn1_object(&object, tag, content.len);
|
||||
chunkcpy(pos, content);
|
||||
|
||||
return object;
|
||||
}
|
||||
|
||||
/* Build an ASN.1 object from a variable number of individual chunks.
|
||||
* Depending on the mode, chunks either are moved ('m') or copied ('c').
|
||||
*/
|
||||
chunk_t
|
||||
asn1_wrap(asn1_t type, const char *mode, ...)
|
||||
{
|
||||
chunk_t construct;
|
||||
va_list chunks;
|
||||
u_char *pos;
|
||||
int i;
|
||||
int count = strlen(mode);
|
||||
|
||||
/* sum up lengths of individual chunks */
|
||||
va_start(chunks, mode);
|
||||
construct.len = 0;
|
||||
for (i = 0; i < count; i++)
|
||||
{
|
||||
chunk_t ch = va_arg(chunks, chunk_t);
|
||||
construct.len += ch.len;
|
||||
}
|
||||
va_end(chunks);
|
||||
|
||||
/* allocate needed memory for construct */
|
||||
pos = build_asn1_object(&construct, type, construct.len);
|
||||
|
||||
/* copy or move the chunks */
|
||||
va_start(chunks, mode);
|
||||
for (i = 0; i < count; i++)
|
||||
{
|
||||
chunk_t ch = va_arg(chunks, chunk_t);
|
||||
|
||||
switch (*mode++)
|
||||
{
|
||||
case 'm':
|
||||
mv_chunk(&pos, ch);
|
||||
break;
|
||||
case 'c':
|
||||
default:
|
||||
chunkcpy(pos, ch);
|
||||
}
|
||||
}
|
||||
va_end(chunks);
|
||||
|
||||
return construct;
|
||||
}
|
||||
|
||||
/*
|
||||
* convert a MP integer into a DER coded ASN.1 object
|
||||
*/
|
||||
chunk_t
|
||||
asn1_integer_from_mpz(const mpz_t value)
|
||||
{
|
||||
size_t bits = mpz_sizeinbase(value, 2); /* size in bits */
|
||||
size_t size = 1 + bits / BITS_PER_BYTE; /* size in bytes */
|
||||
chunk_t n = mpz_to_n(value, size);
|
||||
|
||||
return asn1_wrap(ASN1_INTEGER, "m", n);
|
||||
}
|
||||
|
||||
/*
|
||||
* determines if a character string is of type ASN.1 printableString
|
||||
*/
|
||||
bool
|
||||
is_printablestring(chunk_t str)
|
||||
{
|
||||
const char printablestring_charset[] =
|
||||
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789 '()+,-./:=?";
|
||||
u_int i;
|
||||
|
||||
for (i = 0; i < str.len; i++)
|
||||
{
|
||||
if (strchr(printablestring_charset, str.ptr[i]) == NULL)
|
||||
return FALSE;
|
||||
}
|
||||
return TRUE;
|
||||
}
|
||||
|
||||
/*
|
||||
* Converts ASN.1 UTCTIME or GENERALIZEDTIME into calender time
|
||||
*/
|
||||
time_t
|
||||
asn1totime(const chunk_t *utctime, asn1_t type)
|
||||
{
|
||||
struct tm t;
|
||||
time_t tz_offset;
|
||||
u_char *eot = NULL;
|
||||
|
||||
if ((eot = memchr(utctime->ptr, 'Z', utctime->len)) != NULL)
|
||||
{
|
||||
tz_offset = 0; /* Zulu time with a zero time zone offset */
|
||||
}
|
||||
else if ((eot = memchr(utctime->ptr, '+', utctime->len)) != NULL)
|
||||
{
|
||||
int tz_hour, tz_min;
|
||||
|
||||
sscanf(eot+1, "%2d%2d", &tz_hour, &tz_min);
|
||||
tz_offset = 3600*tz_hour + 60*tz_min; /* positive time zone offset */
|
||||
}
|
||||
else if ((eot = memchr(utctime->ptr, '-', utctime->len)) != NULL)
|
||||
{
|
||||
int tz_hour, tz_min;
|
||||
|
||||
sscanf(eot+1, "%2d%2d", &tz_hour, &tz_min);
|
||||
tz_offset = -3600*tz_hour - 60*tz_min; /* negative time zone offset */
|
||||
}
|
||||
else
|
||||
{
|
||||
return 0; /* error in time format */
|
||||
}
|
||||
|
||||
{
|
||||
const char* format = (type == ASN1_UTCTIME)? "%2d%2d%2d%2d%2d":
|
||||
"%4d%2d%2d%2d%2d";
|
||||
|
||||
sscanf(utctime->ptr, format, &t.tm_year, &t.tm_mon, &t.tm_mday,
|
||||
&t.tm_hour, &t.tm_min);
|
||||
}
|
||||
|
||||
/* is there a seconds field? */
|
||||
if ((eot - utctime->ptr) == ((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 0;
|
||||
}
|
||||
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 */
|
||||
|
||||
return mktime(&t) - timezone - tz_offset;
|
||||
}
|
||||
|
||||
/*
|
||||
* convert a date into ASN.1 UTCTIME or GENERALIZEDTIME format
|
||||
*/
|
||||
chunk_t
|
||||
timetoasn1(const time_t *time, asn1_t type)
|
||||
{
|
||||
int offset;
|
||||
const char *format;
|
||||
char buf[TIMETOA_BUF];
|
||||
chunk_t formatted_time;
|
||||
struct tm *t = gmtime(time);
|
||||
|
||||
if (type == ASN1_GENERALIZEDTIME)
|
||||
{
|
||||
format = "%04d%02d%02d%02d%02d%02dZ";
|
||||
offset = 1900;
|
||||
}
|
||||
else /* ASN1_UTCTIME */
|
||||
{
|
||||
format = "%02d%02d%02d%02d%02d%02dZ";
|
||||
offset = (t->tm_year < 100)? 0 : -100;
|
||||
}
|
||||
sprintf(buf, format, t->tm_year + offset, t->tm_mon + 1, t->tm_mday
|
||||
, t->tm_hour, t->tm_min, t->tm_sec);
|
||||
formatted_time.ptr = buf;
|
||||
formatted_time.len = strlen(buf);
|
||||
return asn1_simple_object(type, formatted_time);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Initializes the internal context of the ASN.1 parser
|
||||
*/
|
||||
void
|
||||
asn1_init(asn1_ctx_t *ctx, chunk_t blob, u_int level0,
|
||||
bool implicit, u_int cond)
|
||||
{
|
||||
ctx->blobs[0] = blob;
|
||||
ctx->level0 = level0;
|
||||
ctx->implicit = implicit;
|
||||
ctx->cond = cond;
|
||||
memset(ctx->loopAddr, '\0', sizeof(ctx->loopAddr));
|
||||
}
|
||||
|
||||
/*
|
||||
* print the value of an ASN.1 simple object
|
||||
*/
|
||||
static void
|
||||
debug_asn1_simple_object(chunk_t object, asn1_t type, u_int cond)
|
||||
{
|
||||
int oid;
|
||||
|
||||
switch (type)
|
||||
{
|
||||
case ASN1_OID:
|
||||
oid = known_oid(object);
|
||||
if (oid != OID_UNKNOWN)
|
||||
{
|
||||
DBG(DBG_PARSING,
|
||||
DBG_log(" '%s'",oid_names[oid].name);
|
||||
)
|
||||
return;
|
||||
}
|
||||
break;
|
||||
case ASN1_UTF8STRING:
|
||||
case ASN1_IA5STRING:
|
||||
case ASN1_PRINTABLESTRING:
|
||||
case ASN1_T61STRING:
|
||||
case ASN1_VISIBLESTRING:
|
||||
DBG(DBG_PARSING,
|
||||
DBG_log(" '%.*s'", (int)object.len, object.ptr);
|
||||
)
|
||||
return;
|
||||
case ASN1_UTCTIME:
|
||||
case ASN1_GENERALIZEDTIME:
|
||||
DBG(DBG_PARSING,
|
||||
time_t time = asn1totime(&object, type);
|
||||
DBG_log(" '%s'", timetoa(&time, TRUE));
|
||||
)
|
||||
return;
|
||||
default:
|
||||
break;
|
||||
}
|
||||
DBG(cond,
|
||||
DBG_dump_chunk("", object);
|
||||
)
|
||||
}
|
||||
|
||||
/*
|
||||
* Parses and extracts the next ASN.1 object
|
||||
*/
|
||||
bool
|
||||
extract_object(asn1Object_t const *objects,
|
||||
u_int *objectID, chunk_t *object, u_int *level, asn1_ctx_t *ctx)
|
||||
{
|
||||
asn1Object_t obj = objects[*objectID];
|
||||
chunk_t *blob;
|
||||
chunk_t *blob1;
|
||||
u_char *start_ptr;
|
||||
|
||||
*object = empty_chunk;
|
||||
|
||||
if (obj.flags & ASN1_END) /* end of loop or option found */
|
||||
{
|
||||
if (ctx->loopAddr[obj.level] && ctx->blobs[obj.level+1].len > 0)
|
||||
{
|
||||
*objectID = ctx->loopAddr[obj.level]; /* another iteration */
|
||||
obj = objects[*objectID];
|
||||
}
|
||||
else
|
||||
{
|
||||
ctx->loopAddr[obj.level] = 0; /* exit loop or option*/
|
||||
return TRUE;
|
||||
}
|
||||
}
|
||||
|
||||
*level = ctx->level0 + obj.level;
|
||||
blob = ctx->blobs + obj.level;
|
||||
blob1 = blob + 1;
|
||||
start_ptr = blob->ptr;
|
||||
|
||||
/* handle ASN.1 defaults values */
|
||||
|
||||
if ((obj.flags & ASN1_DEF)
|
||||
&& (blob->len == 0 || *start_ptr != obj.type) )
|
||||
{
|
||||
/* field is missing */
|
||||
DBG(DBG_PARSING,
|
||||
DBG_log("L%d - %s:", *level, obj.name);
|
||||
)
|
||||
if (obj.type & ASN1_CONSTRUCTED)
|
||||
{
|
||||
(*objectID)++ ; /* skip context-specific tag */
|
||||
}
|
||||
return TRUE;
|
||||
}
|
||||
|
||||
/* handle ASN.1 options */
|
||||
|
||||
if ((obj.flags & ASN1_OPT)
|
||||
&& (blob->len == 0 || *start_ptr != obj.type))
|
||||
{
|
||||
/* advance to end of missing option field */
|
||||
do
|
||||
(*objectID)++;
|
||||
while (!((objects[*objectID].flags & ASN1_END)
|
||||
&& (objects[*objectID].level == obj.level)));
|
||||
return TRUE;
|
||||
}
|
||||
|
||||
/* an ASN.1 object must possess at least a tag and length field */
|
||||
|
||||
if (blob->len < 2)
|
||||
{
|
||||
DBG(DBG_PARSING,
|
||||
DBG_log("L%d - %s: ASN.1 object smaller than 2 octets",
|
||||
*level, obj.name);
|
||||
)
|
||||
return FALSE;
|
||||
}
|
||||
|
||||
blob1->len = asn1_length(blob);
|
||||
|
||||
if (blob1->len == ASN1_INVALID_LENGTH || blob->len < blob1->len)
|
||||
{
|
||||
DBG(DBG_PARSING,
|
||||
DBG_log("L%d - %s: length of ASN.1 object invalid or too large",
|
||||
*level, obj.name);
|
||||
)
|
||||
return FALSE;
|
||||
}
|
||||
|
||||
blob1->ptr = blob->ptr;
|
||||
blob->ptr += blob1->len;
|
||||
blob->len -= blob1->len;
|
||||
|
||||
/* return raw ASN.1 object without prior type checking */
|
||||
|
||||
if (obj.flags & ASN1_RAW)
|
||||
{
|
||||
DBG(DBG_PARSING,
|
||||
DBG_log("L%d - %s:", *level, obj.name);
|
||||
)
|
||||
object->ptr = start_ptr;
|
||||
object->len = (size_t)(blob->ptr - start_ptr);
|
||||
return TRUE;
|
||||
}
|
||||
|
||||
if (*start_ptr != obj.type && !(ctx->implicit && *objectID == 0))
|
||||
{
|
||||
DBG(DBG_PARSING,
|
||||
DBG_log("L%d - %s: ASN1 tag 0x%02x expected, but is 0x%02x",
|
||||
*level, obj.name, obj.type, *start_ptr);
|
||||
DBG_dump("", start_ptr, (u_int)(blob->ptr - start_ptr));
|
||||
)
|
||||
return FALSE;
|
||||
}
|
||||
|
||||
DBG(DBG_PARSING,
|
||||
DBG_log("L%d - %s:", ctx->level0+obj.level, obj.name);
|
||||
)
|
||||
|
||||
/* In case of "SEQUENCE OF" or "SET OF" start a loop */
|
||||
|
||||
if (obj.flags & ASN1_LOOP)
|
||||
{
|
||||
if (blob1->len > 0)
|
||||
{
|
||||
/* at least one item, start the loop */
|
||||
ctx->loopAddr[obj.level] = *objectID + 1;
|
||||
}
|
||||
else
|
||||
{
|
||||
/* no items, advance directly to end of loop */
|
||||
do
|
||||
(*objectID)++;
|
||||
while (!((objects[*objectID].flags & ASN1_END)
|
||||
&& (objects[*objectID].level == obj.level)));
|
||||
return TRUE;
|
||||
}
|
||||
}
|
||||
|
||||
if (obj.flags & ASN1_OBJ)
|
||||
{
|
||||
object->ptr = start_ptr;
|
||||
object->len = (size_t)(blob->ptr - start_ptr);
|
||||
DBG(ctx->cond,
|
||||
DBG_dump_chunk("", *object);
|
||||
)
|
||||
}
|
||||
else if (obj.flags & ASN1_BODY)
|
||||
{
|
||||
*object = *blob1;
|
||||
debug_asn1_simple_object(*object, obj.type, ctx->cond);
|
||||
}
|
||||
return TRUE;
|
||||
}
|
||||
|
||||
/*
|
||||
* parse an ASN.1 simple type
|
||||
*/
|
||||
bool
|
||||
parse_asn1_simple_object(chunk_t *object, asn1_t type, u_int level
|
||||
, const char* name)
|
||||
{
|
||||
size_t len;
|
||||
|
||||
/* an ASN.1 object must possess at least a tag and length field */
|
||||
if (object->len < 2)
|
||||
{
|
||||
DBG(DBG_PARSING,
|
||||
DBG_log("L%d - %s: ASN.1 object smaller than 2 octets",
|
||||
level, name);
|
||||
)
|
||||
return FALSE;
|
||||
}
|
||||
|
||||
if (*object->ptr != type)
|
||||
{
|
||||
DBG(DBG_PARSING,
|
||||
DBG_log("L%d - %s: ASN1 tag 0x%02x expected, but is 0x%02x",
|
||||
level, name, type, *object->ptr);
|
||||
)
|
||||
return FALSE;
|
||||
}
|
||||
|
||||
len = asn1_length(object);
|
||||
|
||||
if (len == ASN1_INVALID_LENGTH || object->len < len)
|
||||
{
|
||||
DBG(DBG_PARSING,
|
||||
DBG_log("L%d - %s: length of ASN.1 object invalid or too large",
|
||||
level, name);
|
||||
)
|
||||
return FALSE;
|
||||
}
|
||||
|
||||
DBG(DBG_PARSING,
|
||||
DBG_log("L%d - %s:", level, name);
|
||||
)
|
||||
debug_asn1_simple_object(*object, type, DBG_RAW);
|
||||
return TRUE;
|
||||
}
|
||||
|
||||
/*
|
||||
* extracts an algorithmIdentifier
|
||||
*/
|
||||
int
|
||||
parse_algorithmIdentifier(chunk_t blob, int level0, chunk_t *parameters)
|
||||
{
|
||||
asn1_ctx_t ctx;
|
||||
chunk_t object;
|
||||
u_int level;
|
||||
int alg = OID_UNKNOWN;
|
||||
int objectID = 0;
|
||||
|
||||
asn1_init(&ctx, blob, level0, FALSE, DBG_RAW);
|
||||
|
||||
while (objectID < ALGORITHM_ID_ROOF)
|
||||
{
|
||||
if (!extract_object(algorithmIdentifierObjects, &objectID, &object, &level, &ctx))
|
||||
return OID_UNKNOWN;
|
||||
|
||||
switch (objectID)
|
||||
{
|
||||
case ALGORITHM_ID_ALG:
|
||||
alg = known_oid(object);
|
||||
break;
|
||||
case ALGORITHM_ID_PARAMETERS:
|
||||
if (parameters != NULL)
|
||||
*parameters = object;
|
||||
break;
|
||||
default:
|
||||
break;
|
||||
}
|
||||
objectID++;
|
||||
}
|
||||
return alg;
|
||||
}
|
||||
|
||||
/*
|
||||
* tests if a blob contains a valid ASN.1 set or sequence
|
||||
*/
|
||||
bool
|
||||
is_asn1(chunk_t blob)
|
||||
{
|
||||
u_int len;
|
||||
u_char tag = *blob.ptr;
|
||||
|
||||
if (tag != ASN1_SEQUENCE && tag != ASN1_SET)
|
||||
{
|
||||
DBG(DBG_PARSING,
|
||||
DBG_log(" file content is not binary ASN.1");
|
||||
)
|
||||
return FALSE;
|
||||
}
|
||||
len = asn1_length(&blob);
|
||||
if (len != blob.len)
|
||||
{
|
||||
DBG(DBG_PARSING,
|
||||
DBG_log(" file size does not match ASN.1 coded length");
|
||||
)
|
||||
return FALSE;
|
||||
}
|
||||
return TRUE;
|
||||
}
|
||||
Reference in New Issue
Block a user