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asn1.cpp
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/*_############################################################################
_##
_## asn1.cpp
_##
_## SNMP++ v3.3
_## -----------------------------------------------
_## Copyright (c) 2001-2013 Jochen Katz, Frank Fock
_##
_## This software is based on SNMP++2.6 from Hewlett Packard:
_##
_## Copyright (c) 1996
_## Hewlett-Packard Company
_##
_## ATTENTION: USE OF THIS SOFTWARE IS SUBJECT TO THE FOLLOWING TERMS.
_## Permission to use, copy, modify, distribute and/or sell this software
_## and/or its documentation is hereby granted without fee. User agrees
_## to display the above copyright notice and this license notice in all
_## copies of the software and any documentation of the software. User
_## agrees to assume all liability for the use of the software;
_## Hewlett-Packard and Jochen Katz make no representations about the
_## suitability of this software for any purpose. It is provided
_## "AS-IS" without warranty of any kind, either express or implied. User
_## hereby grants a royalty-free license to any and all derivatives based
_## upon this software code base.
_##
_##########################################################################*/
/*===================================================================
Copyright (c) 1999
Hewlett-Packard Company
ATTENTION: USE OF THIS SOFTWARE IS SUBJECT TO THE FOLLOWING TERMS.
Permission to use, copy, modify, distribute and/or sell this software
and/or its documentation is hereby granted without fee. User agrees
to display the above copyright notice and this license notice in all
copies of the software and any documentation of the software. User
agrees to assume all liability for the use of the software; Hewlett-Packard
makes no representations about the suitability of this software for any
purpose. It is provided "AS-IS" without warranty of any kind,either express
or implied. User hereby grants a royalty-free license to any and all
derivatives based upon this software code base.
A S N 1. C P P
ASN encoder / decoder implementation
DESIGN + AUTHOR: Peter E. Mellquist
=====================================================================*/
char asn1_cpp_version[]="#(@) SNMP++ $Id$";
#include <libsnmp.h>
#include "snmp_pp/config_snmp_pp.h"
#include "snmp_pp/asn1.h"
#include "snmp_pp/v3.h"
#include "snmp_pp/snmperrs.h"
#include "snmp_pp/log.h"
namespace Snmp_pp {
static const char *loggerModuleName = "snmp++.asn1";
/*
* asn_parse_int - pulls a long out of an ASN int type.
* On entry, datalength is input as the number of valid bytes following
* "data". On exit, it is returned as the number of valid bytes
* following the end of this object.
*
* Returns a pointer to the first byte past the end
* of this object (i.e. the start of the next object).
* Returns NULL on any error.
*/
unsigned char *asn_parse_int(unsigned char *data,
int *datalength,
unsigned char *type,
long *intp)
{
/*
* ASN.1 integer ::= 0x02 asnlength byte {byte}*
* timestamp 0x43 asnlength byte {byte}*
*/
unsigned char *bufp = data;
unsigned long asn_length;
long value = 0;
*type = *bufp++;
if ((*type != 0x02) && (*type != 0x43) &&
(*type != 0x41)) {
ASNERROR("Wrong Type. Not an integer");
return NULL;
}
bufp = asn_parse_length(bufp, &asn_length);
if (bufp == NULL) {
ASNERROR("bad length");
return NULL;
}
if ((asn_length + (bufp - data)) > (unsigned long)(*datalength)) {
ASNERROR("overflow of message (int)");
return NULL;
}
if (asn_length > sizeof(*intp)) {
ASNERROR("I don't support such large integers");
return NULL;
}
*datalength -= (int)asn_length + SAFE_INT_CAST(bufp - data);
if (*bufp & 0x80)
value = -1; /* integer is negative */
while(asn_length--)
value = (value << 8) | *bufp++;
*intp = value;
return bufp;
}
/*
* asn_parse_unsigned_int - pulls an unsigned long out of an ASN int type.
* On entry, datalength is input as the number of valid bytes following
* "data". On exit, it is returned as the number of valid bytes
* following the end of this object.
*
* Returns a pointer to the first byte past the end
* of this object (i.e. the start of the next object).
* Returns NULL on any error.
*/
unsigned char *asn_parse_unsigned_int(unsigned char *data,
int *datalength,
unsigned char *type,
unsigned long *intp)
{
/*
* ASN.1 integer ::= 0x02 asnlength byte {byte}*
* 0x43 asnlength byte {byte}*
*/
unsigned char *bufp = data;
unsigned long asn_length;
unsigned long value = 0;
// get the type
*type = *bufp++;
if ((*type != 0x02) && (*type != 0x43) &&
(*type != 0x41) && (*type != 0x42) &&
(*type != 0x47)) {
ASNERROR("Wrong Type. Not an unsigned integer");
return NULL;
}
// pick up the len
bufp = asn_parse_length(bufp, &asn_length);
if (bufp == NULL) {
ASNERROR("bad length");
return NULL;
}
// check the len for message overflow
if ((asn_length + (bufp - data)) > (unsigned long)(*datalength)) {
ASNERROR("overflow of message (uint)");
return NULL;
}
// check for legal uint size
if ((asn_length > 5) || ((asn_length > 4) && (*bufp != 0x00))) {
ASNERROR("I don't support such large integers");
return NULL;
}
// check for leading 0 octet
if (*bufp == 0x00) {
bufp++;
asn_length--;
}
// fix the returned data length value
*datalength -= (int)asn_length + SAFE_INT_CAST(bufp - data);
// calculate the value
for (long i=0;i<(long)asn_length;i++)
value = (value << 8) + (unsigned long) *bufp++;
*intp = value; // assign return value
return bufp; // return the bumped pointer
}
/*
* asn_build_int - builds an ASN object containing an integer.
* On entry, datalength is input as the number of valid bytes following
* "data". On exit, it is returned as the number of valid bytes
* following the end of this object.
*
* Returns a pointer to the first byte past the end
* of this object (i.e. the start of the next object).
* Returns NULL on any error.
*/
unsigned char *asn_build_int(unsigned char *data, int *datalength,
const unsigned char type,
const long *intp)
{
/*
* ASN.1 integer ::= 0x02 asnlength byte {byte}*
*/
long integer = *intp;
unsigned long mask;
int intsize = sizeof(long);
/* Truncate "unnecessary" bytes off of the most significant end of this
* 2's complement integer. There should be no sequence of 9
* consecutive 1's or 0's at the most significant end of the
* integer.
*/
mask = 0x1FFul << ((8 * (sizeof(long) - 1)) - 1);
/* mask is 0xFF800000 on a big-endian machine */
while((((integer & mask) == 0) || ((integer & mask) == mask))
&& intsize > 1) {
intsize--;
integer <<= 8;
}
data = asn_build_header(data, datalength, type, intsize);
if (data == NULL) return NULL;
if (*datalength < intsize) return NULL;
*datalength -= intsize;
mask = 0xFFul << (8 * (sizeof(long) - 1));
/* mask is 0xFF000000 on a big-endian machine */
while(intsize--) {
*data++ = (unsigned char)((integer & mask) >> (8 * (sizeof(long) - 1)));
integer <<= 8;
}
return data;
}
/*
* asn_build_unsigned_int - builds an ASN object containing an integer.
* On entry, datalength is input as the number of valid bytes following
* "data". On exit, it is returned as the number of valid bytes
* following the end of this object.
*
* Returns a pointer to the first byte past the end
* of this object (i.e. the start of the next object).
* Returns NULL on any error.
*/
unsigned char *asn_build_unsigned_int(unsigned char *data, // modified data
int *datalength, // returned buffer length
unsigned char type, // SMI type
unsigned long *intp) // Uint to encode
{
/*
* ASN.1 integer ::= 0x02 asnlength byte {byte}*
*/
unsigned long u_integer = *intp;
long u_integer_len;
long x;
// figure out the len
if (((u_integer >> 24) & 0xFF) != 0)
u_integer_len = 4;
else if (((u_integer >> 16) & 0xFF) !=0)
u_integer_len = 3;
else if (((u_integer >> 8) & 0xFF) !=0)
u_integer_len = 2;
else
u_integer_len = 1;
// check for 5 byte len where first byte will be a null
if (((u_integer >> (8 * (u_integer_len -1))) & 0x080) !=0) {
u_integer_len++;
}
// build up the header
data = asn_build_header(data, datalength, type, u_integer_len);
if (data == NULL) return NULL;
if (*datalength < u_integer_len) return NULL;
// special case, add a null byte for len of 5
if (u_integer_len == 5) {
*data++ = 0;
for (x=1;x<u_integer_len;x++)
*data++= (unsigned char) (u_integer >> (8 * ((u_integer_len-1)-x)& 0xFF));
}
else
{
for (x=0;x<u_integer_len;x++)
*data++= (unsigned char) (u_integer >> (8 * ((u_integer_len-1)-x)& 0xFF));
}
*datalength -= u_integer_len;
return data;
}
/*
* asn_parse_string - pulls an octet string out of an ASN octet string type.
* On entry, datalength is input as the number of valid bytes following
* "data". On exit, it is returned as the number of valid bytes
* following the beginning of the next object.
*
* "string" is filled with the octet string.
*
* Returns a pointer to the first byte past the end
* of this object (i.e. the start of the next object).
* Returns NULL on any error.
*/
unsigned char *asn_parse_string(unsigned char *data,
int *datalength,
unsigned char *type,
unsigned char *str,
int *strlength)
{
/*
* ASN.1 octet string ::= primstring | cmpdstring
* primstring ::= 0x04 asnlength byte {byte}*
* cmpdstring ::= 0x24 asnlength string {string}*
* ipaddress ::= 0x40 4 byte byte byte byte
*/
unsigned char *bufp = data;
unsigned long asn_length;
*type = *bufp++;
if ((*type != 0x04) && (*type != 0x24) &&
(*type != 0x40) && (*type != 0x44) &&
(*type != 0x45)) {
ASNERROR("asn parse string: Wrong Type. Not a string");
return NULL;
}
bufp = asn_parse_length(bufp, &asn_length);
if (bufp == NULL)
return NULL;
if ((asn_length + (bufp - data)) > (unsigned long)(*datalength)) {
ASNERROR("asn parse string: overflow of message");
return NULL;
}
if ((int)asn_length > *strlength) {
ASNERROR("asn parse string: String to parse is longer than buffer, aborting parsing.");
return NULL;
}
memcpy(str, bufp, asn_length);
*strlength = (int)asn_length;
*datalength -= (int)asn_length + SAFE_INT_CAST(bufp - data);
return bufp + asn_length;
}
/*
* asn_build_string - Builds an ASN octet string object containing the input string.
* On entry, datalength is input as the number of valid bytes following
* "data". On exit, it is returned as the number of valid bytes
* following the beginning of the next object.
*
* Returns a pointer to the first byte past the end
* of this object (i.e. the start of the next object).
* Returns NULL on any error.
*/
unsigned char *asn_build_string(unsigned char *data,
int *datalength,
const unsigned char type,
const unsigned char *string,
const int strlength)
{
/*
* ASN.1 octet string ::= primstring | cmpdstring
* primstring ::= 0x04 asnlength byte {byte}*
* cmpdstring ::= 0x24 asnlength string {string}*
* This code will never send a compound string.
*/
data = asn_build_header(data, datalength, type, strlength);
if (data == NULL) return NULL;
if (*datalength < strlength) return NULL;
memcpy(data, string, strlength);
*datalength -= strlength;
return data + strlength;
}
/*
* asn_parse_header - interprets the ID and length of the current object.
* On entry, datalength is input as the number of valid bytes following
* "data". On exit, it is returned as the number of valid bytes
* in this object following the id and length.
*
* Returns a pointer to the first byte of the contents of this object.
* Returns NULL on any error.
*/
unsigned char *asn_parse_header(unsigned char *data,
int *datalength,
unsigned char *type)
{
unsigned char *bufp = data;
unsigned long asn_length;
/* this only works on data types < 30, i.e. no extension octets */
if (IS_EXTENSION_ID(*bufp)) {
ASNERROR("can't process ID >= 30");
return NULL;
}
*type = *bufp;
bufp = asn_parse_length(bufp + 1, &asn_length);
if (bufp == NULL)
return NULL;
int header_len = SAFE_INT_CAST(bufp - data);
if ((unsigned long)(header_len + asn_length) > (unsigned long)*datalength) {
ASNERROR("asn length too long");
return NULL;
}
*datalength = (int)asn_length;
return bufp;
}
/*
* asn_build_header - builds an ASN header for an object with the ID and
* length specified.
* On entry, datalength is input as the number of valid bytes following
* "data". On exit, it is returned as the number of valid bytes
* in this object following the id and length.
*
* This only works on data types < 30, i.e. no extension octets.
* The maximum length is 0xFFFF;
*
* Returns a pointer to the first byte of the contents of this object.
* Returns NULL on any error.
*/
unsigned char *asn_build_header(unsigned char *data,
int *datalength,
unsigned char type,
int length)
{
if (*datalength < 1)
return NULL;
*data++ = type;
(*datalength)--;
return asn_build_length(data, datalength, length);
}
/*
* asn_build_sequence - builds an ASN header for a sequence with the ID and
* length specified.
*
* This only works on data types < 30, i.e. no extension octets.
*
* Returns a pointer to the first byte of the contents of this object.
* Returns NULL on any error.
*/
unsigned char *asn_build_sequence(unsigned char *data,
int *datalength,
unsigned char type,
int length)
{
if (*datalength < 2) /* need at least two octets for a sequence */
{
ASNERROR("build_sequence");
return NULL;
}
*data++ = type;
(*datalength)--;
unsigned char *data_with_length = asn_build_length(data, datalength, length);
if (data_with_length == NULL)
{
(*datalength)++; /* correct datalength to emulate old behavior of build_sequence */
return NULL;
}
return data_with_length;
}
/*
* asn_parse_length - interprets the length of the current object.
* On exit, length contains the value of this length field.
*
* Returns a pointer to the first byte after this length
* field (aka: the start of the data field).
* Returns NULL on any error.
*/
unsigned char * asn_parse_length(unsigned char *data,
unsigned long *length)
{
unsigned char lengthbyte = *data;
*length = 0;
if (lengthbyte & ASN_LONG_LEN) {
lengthbyte &= ~ASN_LONG_LEN; /* turn MSb off */
if (lengthbyte == 0) {
ASNERROR("We don't support indefinite lengths");
return NULL;
}
if (lengthbyte > sizeof(int)) {
ASNERROR("we can't support data lengths that long");
return NULL;
}
for (int i=0 ; i < lengthbyte ; i++)
{
*length = (*length << 8) + *(data + 1 + i);
}
// check for length greater than 2^31
if (*length > 0x80000000ul) {
ASNERROR("SNMP does not support data lengths > 2^31");
return NULL;
}
return data + lengthbyte + 1;
} else { /* short asnlength */
*length = (long)lengthbyte;
return data + 1;
}
}
unsigned char *asn_build_length(unsigned char *data,
int *datalength,
int length)
{
unsigned char *start_data = data;
/* no indefinite lengths sent */
if (length < 0x80) {
if (*datalength < 1) {
ASNERROR("build_length");
return NULL;
}
*data++ = (unsigned char)length;
}
else if (length <= 0xFF) {
if (*datalength < 2) {
ASNERROR("build_length");
return NULL;
}
*data++ = (unsigned char)(0x01 | ASN_LONG_LEN);
*data++ = (unsigned char)length;
}
else if (length <= 0xFFFF) { /* 0xFF < length <= 0xFFFF */
if (*datalength < 3) {
ASNERROR("build_length");
return NULL;
}
*data++ = (unsigned char)(0x02 | ASN_LONG_LEN);
*data++ = (unsigned char)((length >> 8) & 0xFF);
*data++ = (unsigned char)(length & 0xFF);
}
else if (length <= 0xFFFFFF) { /* 0xFF < length <= 0xFFFF */
if (*datalength < 4) {
ASNERROR("build_length");
return NULL;
}
*data++ = (unsigned char)(0x03 | ASN_LONG_LEN);
*data++ = (unsigned char)((length >> 16) & 0xFF);
*data++ = (unsigned char)((length >> 8) & 0xFF);
*data++ = (unsigned char)(length & 0xFF);
}
else {
if (*datalength < 5) {
ASNERROR("build_length");
return NULL;
}
*data++ = (unsigned char)(0x04 | ASN_LONG_LEN);
*data++ = (unsigned char)((length >> 24) & 0xFF);
*data++ = (unsigned char)((length >> 16) & 0xFF);
*data++ = (unsigned char)((length >> 8) & 0xFF);
*data++ = (unsigned char)(length & 0xFF);
}
*datalength -= SAFE_INT_CAST(data - start_data);
return data;
}
/*
* asn_parse_objid - pulls an object indentifier out of an ASN object identifier type.
* On entry, datalength is input as the number of valid bytes following
* "data". On exit, it is returned as the number of valid bytes
* following the beginning of the next object.
*
* "objid" is filled with the object identifier.
*
* Returns a pointer to the first byte past the end
* of this object (i.e. the start of the next object).
* Returns NULL on any error.
*/
unsigned char *asn_parse_objid(unsigned char *data,
int *datalength,
unsigned char *type,
oid *objid,
int *objidlength)
{
/*
* ASN.1 objid ::= 0x06 asnlength subidentifier {subidentifier}*
* subidentifier ::= {leadingbyte}* lastbyte
* leadingbyte ::= 1 7bitvalue
* lastbyte ::= 0 7bitvalue
*/
unsigned char *bufp = data;
oid *oidp = objid + 1;
unsigned long subidentifier;
long length;
unsigned long asn_length;
*type = *bufp++;
if (*type != 0x06) {
ASNERROR("Wrong Type. Not an oid");
return NULL;
}
bufp = asn_parse_length(bufp, &asn_length);
if (bufp == NULL)
return NULL;
if ((asn_length + (bufp - data)) > (unsigned long)(*datalength)) {
ASNERROR("overflow of message (objid)");
return NULL;
}
*datalength -= (int)asn_length + SAFE_INT_CAST(bufp - data);
/* Handle invalid object identifier encodings of the form 06 00 robustly */
if (asn_length == 0)
objid[0] = objid[1] = 0;
length = asn_length;
(*objidlength)--; /* account for expansion of first byte */
while (length > 0 && (*objidlength)-- > 0) {
subidentifier = 0;
do { /* shift and add in low order 7 bits */
subidentifier = (subidentifier << 7) + (*(unsigned char *)bufp & ~ASN_BIT8);
length--;
} while (*(unsigned char *)bufp++ & ASN_BIT8); /* last byte has high bit clear */
if (subidentifier > (unsigned long)MAX_SUBID) {
ASNERROR("subidentifier too long");
return NULL;
}
*oidp++ = (oid)subidentifier;
}
/*
* The first two subidentifiers are encoded into the first component
* with the value (X * 40) + Y, where:
* X is the value of the first subidentifier.
* Y is the value of the second subidentifier.
*/
subidentifier = (unsigned long)objid[1];
if (subidentifier == 0x2B) {
objid[0] = 1;
objid[1] = 3;
} else if (subidentifier < 40) {
objid[0] = 0;
objid[1] = (oid)subidentifier;
} else if (subidentifier < 80) {
objid[0] = 1;
objid[1] = (oid)(subidentifier - 40);
}
else {
objid[0] = 2;
objid[1] = (oid)(subidentifier - 80);
}
*objidlength = (int)(oidp - objid);
return bufp;
}
/*
* asn_build_objid - Builds an ASN object identifier object containing the
* input string.
* On entry, datalength is input as the number of valid bytes following
* "data". On exit, it is returned as the number of valid bytes
* following the beginning of the next object.
*
* Returns a pointer to the first byte past the end
* of this object (i.e. the start of the next object).
* Returns NULL on any error.
*/
unsigned char *asn_build_objid(unsigned char *data,
int *datalength,
unsigned char type,
oid *objid,
int objidlength)
{
/*
* ASN.1 objid ::= 0x06 asnlength subidentifier {subidentifier}*
* subidentifier ::= {leadingbyte}* lastbyte
* leadingbyte ::= 1 7bitvalue
* lastbyte ::= 0 7bitvalue
*/
// F.Fock correct buffer size must be 5*8bit*MAX_OID_LEN
unsigned char buf[MAX_OID_LEN*5];
unsigned char *bp = buf;
oid *op = objid;
int asnlength;
if (objidlength > MAX_OID_LEN) {
ASNERROR("Too many sub-identifiers.");
objidlength = MAX_OID_LEN;
}
if (objidlength < 2) {
*bp++ = 0;
objidlength = 0;
} else {
asn_build_subid(op[1] + (op[0] * 40), bp);
objidlength -= 2;
op += 2;
}
while(objidlength-- > 0) {
asn_build_subid(*op++, bp);
}
asnlength = SAFE_INT_CAST(bp - buf);
data = asn_build_header(data, datalength, type, asnlength);
if (data == NULL) return NULL;
if (*datalength < asnlength) return NULL;
memcpy((char *)data, (char *)buf, asnlength);
*datalength -= asnlength;
return data + asnlength;
}
/**
* Add the given sub-identifier to the OID byte buffer and forward its pointer
* accordingly for appending the next one.
* @param subid
* the sub-identifier (32-bit unsigned) to add.
* @param bp
* the buffer pointer. On return, the pointer will be increased at least
* by one (character) and at most by five.
*/
void asn_build_subid(unsigned long subid, unsigned char*& bp) {
unsigned long mask, testmask;
int bits, testbits;
if (subid < 127) { /* off by one? */
*bp++ = (unsigned char)subid;
} else {
mask = 0x7F; /* handle subid == 0 case */
bits = 0;
/* testmask *MUST* !!!! be of an unsigned type */
for(testmask = 0x7F, testbits = 0; testmask != 0;
testmask <<= 7, testbits += 7) {
if (subid & testmask) { /* if any bits set */
mask = testmask;
bits = testbits;
}
}
/* mask can't be zero here */
for(;mask != 0x7F; mask >>= 7, bits -= 7) {
/* fix a mask that got truncated above */
if (mask == 0x1E00000)
mask = 0xFE00000;
*bp++ = (unsigned char)(((subid & mask) >> bits) | ASN_BIT8);
}
*bp++ = (unsigned char)(subid & mask);
}
}
/*
* asn_parse_null - Interprets an ASN null type.
* On entry, datalength is input as the number of valid bytes following
* "data". On exit, it is returned as the number of valid bytes
* following the beginning of the next object.
*
* Returns a pointer to the first byte past the end
* of this object (i.e. the start of the next object).
* Returns NULL on any error.
*/
unsigned char *asn_parse_null(unsigned char *data,
int *datalength,
unsigned char *type)
{
/*
* ASN.1 null ::= 0x05 0x00
*/
unsigned char *bufp = data;
unsigned long asn_length;
*type = *bufp++;
if (*type != 0x05) {
ASNERROR("Wrong Type. Not a null");
return NULL;
}
bufp = asn_parse_length(bufp, &asn_length);
if (bufp == NULL)
return NULL;
if (asn_length != 0) {
ASNERROR("Malformed NULL");
return NULL;
}
*datalength -= SAFE_INT_CAST(bufp - data);
return bufp + asn_length;
}
/*
* asn_build_null - Builds an ASN null object.
* On entry, datalength is input as the number of valid bytes following
* "data". On exit, it is returned as the number of valid bytes
* following the beginning of the next object.
*
* Returns a pointer to the first byte past the end
* of this object (i.e. the start of the next object).
* Returns NULL on any error.
*/
unsigned char *asn_build_null(unsigned char *data,
int *datalength,
unsigned char type)
{
/*
* ASN.1 null ::= 0x05 0x00
*/
return asn_build_header(data, datalength, type, 0);
}
/*
* asn_parse_bitstring - pulls a bitstring out of an ASN bitstring type.
* On entry, datalength is input as the number of valid bytes following
* "data". On exit, it is returned as the number of valid bytes
* following the beginning of the next object.
*
* "string" is filled with the bit string.
*
* Returns a pointer to the first byte past the end
* of this object (i.e. the start of the next object).
* Returns NULL on any error.
*/
unsigned char *asn_parse_bitstring(unsigned char *data,
int *datalength,
unsigned char *type,
unsigned char *string,
int *strlength)
{
/*
* bitstring ::= 0x03 asnlength unused {byte}*
*/
unsigned char *bufp = data;
unsigned long asn_length;
*type = *bufp++;
if (*type != 0x03) {
ASNERROR("Wrong Type. Not a bitstring");
return NULL;
}
bufp = asn_parse_length(bufp, &asn_length);
if (bufp == NULL)
return NULL;
if ((asn_length + (bufp - data)) > (unsigned long)(*datalength)) {
ASNERROR("overflow of message (bitstring)");
return NULL;
}
if ((int) asn_length > *strlength) {
ASNERROR("I don't support such long bitstrings");
return NULL;
}
if (asn_length < 1) {
ASNERROR("Invalid bitstring");
return NULL;
}
if (*bufp > 7) {
ASNERROR("Invalid bitstring");
return NULL;
}
memcpy((char *)string,(char *)bufp, (int)asn_length);
*strlength = (int)asn_length;
*datalength -= (int)asn_length + SAFE_INT_CAST(bufp - data);
return bufp + asn_length;
}
/*
* asn_build_bitstring - Builds an ASN bit string object containing the
* input string.
* On entry, datalength is input as the number of valid bytes following
* "data". On exit, it is returned as the number of valid bytes
* following the beginning of the next object.
*
* Returns a pointer to the first byte past the end
* of this object (i.e. the start of the next object).
* Returns NULL on any error.
*/
unsigned char *asn_build_bitstring(unsigned char *data,
int *datalength,
unsigned char type,
unsigned char *string,
int strlength)
{
/*
* ASN.1 bit string ::= 0x03 asnlength unused {byte}*
*/
if (strlength < 1 || *string > 7) {
ASNERROR("Building invalid bitstring");
return NULL;
}
data = asn_build_header(data, datalength, type, strlength);
if (data == NULL) return NULL;
if (*datalength < strlength) return NULL;
memcpy((char *)data,(char *)string, strlength);
*datalength -= strlength;
return data + strlength;
}
/*
* asn_parse_unsigned_int64 - pulls a 64 bit unsigned long out of an ASN int
* type.
* On entry, datalength is input as the number of valid bytes following
* "data". On exit, it is returned as the number of valid bytes
* following the end of this object.
*
* Returns a pointer to the first byte past the end
* of this object (i.e. the start of the next object).
* Returns NULL on any error.
*/
unsigned char *asn_parse_unsigned_int64(unsigned char *data,
int *datalength,
unsigned char *type,
struct counter64 *cp)
{
/*
* ASN.1 integer ::= 0x02 asnlength byte {byte}*
*/
unsigned char *bufp = data;
unsigned long asn_length;
unsigned long low = 0, high = 0;
*type = *bufp++;
if ((*type != 0x02) && (*type != 0x46)) {
ASNERROR("Wrong Type. Not an integer 64");
return NULL;
}
bufp = asn_parse_length(bufp, &asn_length);
if (bufp == NULL) {
ASNERROR("bad length");
return NULL;
}
if ((asn_length + (bufp - data)) > (unsigned long)(*datalength)) {
ASNERROR("overflow of message (uint64)");
return NULL;
}
if (((int)asn_length > 9) ||
(((int)asn_length == 9) && *bufp != 0x00)) {
ASNERROR("I don't support such large integers");
return NULL;
}
*datalength -= (int)asn_length + SAFE_INT_CAST(bufp - data);
if (*bufp & 0x80) {
low = (unsigned long) -1; // integer is negative
high = (unsigned long) -1;
}
while(asn_length--) {
high = (high << 8) | ((low & 0xFF000000) >> 24);
low = ((low << 8) | *bufp++) & 0xFFFFFFFF;
}
cp->low = low;
cp->high = high;
return bufp;
}
/*
* asn_build_unsigned_int64 - builds an ASN object containing a 64 bit integer.
* On entry, datalength is input as the number of valid bytes following
* "data". On exit, it is returned as the number of valid bytes
* following the end of this object.
*
* Returns a pointer to the first byte past the end
* of this object (i.e. the start of the next object).
* Returns NULL on any error.
*/
unsigned char *asn_build_unsigned_int64(unsigned char *data,
int *datalength,
unsigned char type,
struct counter64 *cp)
{
/*
* ASN.1 integer ::= 0x02 asnlength byte {byte}*
*/
unsigned long low = cp->low;
unsigned long high = cp->high;
unsigned long mask = 0xFF000000ul;
int add_null_byte = 0;
int intsize = 8;
if (((high & mask) >> 24) & 0x80) {
/* if MSB is set */
add_null_byte = 1;
intsize++;
}
else {
/*
* Truncate "unnecessary" bytes off of the most significant end of this 2's
* complement integer.
* There should be no sequence of 9 consecutive 1's or 0's at the most
* significant end of the integer.
*/
unsigned long mask2 = 0xFF800000ul;
while ((((high & mask2) == 0) || ((high & mask2) == mask2)) &&
(intsize > 1)) {
intsize--;
high = (high << 8) | ((low & mask) >> 24);
low <<= 8;
}
}
data = asn_build_header(data, datalength, type, intsize);
if (data == NULL) return NULL;
if (*datalength < intsize) return NULL;
*datalength -= intsize;
if (add_null_byte == 1) {
*data++ = 0;
intsize--;
}
while(intsize--) {
*data++ = (unsigned char)((high & mask) >> 24);
high = (high << 8) | ((low & mask) >> 24);
low <<= 8;