denozord/strongswan-ext
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

refactoring of the ASN.1 parser

Browse Source
This commit is contained in:
Andreas Steffen
2008-04-26 09:24:14 +00:00
parent 3444390241
commit d3d7e46b8c
19 changed files with 1587 additions and 1166 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/libstrongswan/asn1/asn1.c
+84 -233
View File
@@ -1,6 +1,7 @@
/*
* Copyright (C) 2006 Martin Will
* Copyright (C) 2000-2008 Andreas Steffen
*
* Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
@@ -20,12 +21,16 @@
#include <string.h>
#include <time.h>
#include "asn1.h"
#include <library.h>
#include <debug.h>
/* some common prefabricated ASN.1 constants */
#include "oid.h"
#include "asn1.h"
#include "asn1_parser.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 };
@@ -34,7 +39,9 @@ const chunk_t ASN1_INTEGER_0 = chunk_from_buf(ASN1_INTEGER_0_str);
const chunk_t ASN1_INTEGER_1 = chunk_from_buf(ASN1_INTEGER_1_str);
const chunk_t ASN1_INTEGER_2 = chunk_from_buf(ASN1_INTEGER_2_str);
/* some popular algorithmIdentifiers */
/**
* some popular algorithmIdentifiers
*/
static u_char ASN1_md2_id_str[] = {
0x30, 0x0c,
@@ -141,19 +148,8 @@ static const chunk_t ASN1_sha256WithRSA_id = chunk_from_buf(ASN1_sha256WithRSA_i
static const chunk_t ASN1_sha384WithRSA_id = chunk_from_buf(ASN1_sha384WithRSA_id_str);
static const chunk_t ASN1_sha512WithRSA_id = chunk_from_buf(ASN1_sha512WithRSA_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
/*
* Defined in header.
*/
chunk_t asn1_algorithmIdentifier(int oid)
{
@@ -190,11 +186,10 @@ chunk_t asn1_algorithmIdentifier(int oid)
}
}
/**
* 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
/*
* Defined in header.
*/
int known_oid(chunk_t object)
int asn1_known_oid(chunk_t object)
{
int oid = 0;
@@ -222,8 +217,8 @@ int known_oid(chunk_t object)
return -1;
}
/**
* Decodes the length in bytes of an ASN.1 object
/*
* Defined in header.
*/
u_int asn1_length(chunk_t *blob)
{
@@ -269,27 +264,10 @@ u_int asn1_length(chunk_t *blob)
return len;
}
/**
* 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)
time_t asn1_to_time(const chunk_t *utctime, asn1_t type)
{
struct tm t;
time_t tz_offset;
@@ -364,7 +342,7 @@ time_t asn1totime(const chunk_t *utctime, asn1_t type)
/**
* Convert a date into ASN.1 UTCTIME or GENERALIZEDTIME format
*/
chunk_t timetoasn1(const time_t *time, asn1_t type)
chunk_t asn1_from_time(const time_t *time, asn1_t type)
{
int offset;
const char *format;
@@ -389,31 +367,17 @@ chunk_t timetoasn1(const time_t *time, asn1_t type)
return asn1_simple_object(type, formatted_time);
}
/**
* Initializes the internal context of the ASN.1 parser
/*
* Defined in header.
*/
void asn1_init(asn1_ctx_t *ctx, chunk_t blob, u_int level0,
bool implicit, bool private)
{
ctx->blobs[0] = blob;
ctx->level0 = level0;
ctx->implicit = implicit;
ctx->private = private;
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, bool private)
void asn1_debug_simple_object(chunk_t object, asn1_t type, bool private)
{
int oid;
switch (type)
{
case ASN1_OID:
oid = known_oid(object);
oid = asn1_known_oid(object);
if (oid != OID_UNKNOWN)
{
DBG2(" '%s'", oid_names[oid].name);
@@ -430,7 +394,7 @@ static void debug_asn1_simple_object(chunk_t object, asn1_t type, bool private)
case ASN1_UTCTIME:
case ASN1_GENERALIZEDTIME:
{
time_t time = asn1totime(&object, type);
time_t time = asn1_to_time(&object, type);
DBG2(" '%T'", &time);
}
@@ -448,148 +412,10 @@ static void debug_asn1_simple_object(chunk_t object, asn1_t type, bool private)
}
}
/**
* 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 = chunk_empty;
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 */
DBG2("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)
{
DBG1("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)
{
DBG1("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)
{
DBG2("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))
{
DBG1("L%d - %s: ASN1 tag 0x%02x expected, but is 0x%02x",
*level, obj.name, obj.type, *start_ptr);
DBG3("%b", start_ptr, (u_int)(blob->ptr - start_ptr));
return FALSE;
}
DBG2("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);
if (ctx->private)
{
DBG4("%B", object);
}
else
{
DBG3("%B", object);
}
}
else if (obj.flags & ASN1_BODY)
{
*object = *blob1;
debug_asn1_simple_object(*object, obj.type, ctx->private);
}
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)
bool asn1_parse_simple_object(chunk_t *object, asn1_t type, u_int level, const char* name)
{
size_t len;
@@ -617,32 +443,42 @@ bool parse_asn1_simple_object(chunk_t *object, asn1_t type, u_int level, const c
}
DBG2("L%d - %s:", level, name);
debug_asn1_simple_object(*object, type, FALSE);
asn1_debug_simple_object(*object, type, FALSE);
return TRUE;
}
/**
* extracts an algorithmIdentifier
* ASN.1 definition of an algorithmIdentifier
*/
int parse_algorithmIdentifier(chunk_t blob, int level0, chunk_t *parameters)
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
/*
* Defined in header
*/
int asn1_parse_algorithmIdentifier(chunk_t blob, int level0, chunk_t *parameters)
{
asn1_ctx_t ctx;
asn1_parser_t *parser;
chunk_t object;
u_int level;
int objectID;
int alg = OID_UNKNOWN;
int objectID = 0;
asn1_init(&ctx, blob, level0, FALSE, FALSE);
parser = asn1_parser_create(algorithmIdentifierObjects, ALGORITHM_ID_ROOF,
blob);
parser->set_top_level(parser, level0);
while (objectID < ALGORITHM_ID_ROOF)
while (parser->iterate(parser, &objectID, &object))
{
if (!extract_object(algorithmIdentifierObjects, &objectID, &object, &level, &ctx))
return OID_UNKNOWN;
switch (objectID)
{
case ALGORITHM_ID_ALG:
alg = known_oid(object);
alg = asn1_known_oid(object);
break;
case ALGORITHM_ID_PARAMETERS:
if (parameters != NULL)
@@ -651,8 +487,8 @@ int parse_algorithmIdentifier(chunk_t blob, int level0, chunk_t *parameters)
default:
break;
}
objectID++;
}
parser->destroy(parser);
return alg;
}
@@ -688,10 +524,27 @@ bool is_asn1(chunk_t blob)
return FALSE;
}
/*
* Defined in header.
*/
bool asn1_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;
}
/**
* codes ASN.1 lengths up to a size of 16'777'215 bytes
*/
void code_asn1_length(size_t length, chunk_t *code)
static void asn1_code_length(size_t length, chunk_t *code)
{
if (length < 128)
{
@@ -724,14 +577,14 @@ void code_asn1_length(size_t length, chunk_t *code)
/**
* 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* asn1_build_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);
asn1_code_length(datalen, &length);
/* allocate memory for the asn.1 TLV object */
object->len = 1 + length.len + datalen;
@@ -751,13 +604,13 @@ u_char* build_asn1_object(chunk_t *object, asn1_t type, size_t datalen)
}
/**
* build a simple ASN.1 object
* 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);
u_char *pos = asn1_build_object(&object, tag, content.len);
memcpy(pos, content.ptr, content.len);
pos += content.len;
@@ -770,7 +623,7 @@ chunk_t asn1_simple_object(asn1_t tag, chunk_t content)
chunk_t asn1_bitstring(const char *mode, chunk_t content)
{
chunk_t object;
u_char *pos = build_asn1_object(&object, ASN1_BIT_STRING, 1 + content.len);
u_char *pos = asn1_build_object(&object, ASN1_BIT_STRING, 1 + content.len);
*pos++ = 0x00;
memcpy(pos, content.ptr, content.len);
@@ -804,7 +657,7 @@ chunk_t asn1_wrap(asn1_t type, const char *mode, ...)
va_end(chunks);
/* allocate needed memory for construct */
pos = build_asn1_object(&construct, type, construct.len);
pos = asn1_build_object(&construct, type, construct.len);
/* copy or move the chunks */
va_start(chunks, mode);
@@ -841,26 +694,24 @@ static const asn1Object_t timeObjects[] = {
/**
* extracts and converts a UTCTIME or GENERALIZEDTIME object
*/
time_t parse_time(chunk_t blob, int level0)
time_t asn1_parse_time(chunk_t blob, int level0)
{
asn1_ctx_t ctx;
asn1_parser_t *parser;
chunk_t object;
u_int level;
int objectID = 0;
int objectID;
time_t utc_time = 0;
asn1_init(&ctx, blob, level0, FALSE, FALSE);
parser= asn1_parser_create(timeObjects, TIME_ROOF, blob);
parser->set_top_level(parser, level0);
while (objectID < TIME_ROOF)
while (parser->iterate(parser, &objectID, &object))
{
if (!extract_object(timeObjects, &objectID, &object, &level, &ctx))
return 0;
if (objectID == TIME_UTC || objectID == TIME_GENERALIZED)
{
return asn1totime(&object, (objectID == TIME_UTC)
? ASN1_UTCTIME : ASN1_GENERALIZEDTIME);
utc_time = asn1_to_time(&object, (objectID == TIME_UTC)
? ASN1_UTCTIME : ASN1_GENERALIZEDTIME);
}
objectID++;
}
return 0;
parser->destroy(parser);
return utc_time;
}