/**
* FreeRDP: A Remote Desktop Protocol Implementation
* ASN.1 Encoding Rules (BER/DER common functions)
*
* Copyright 2011 Marc-Andre Moreau <marcandre.moreau@gmail.com>
* Modified by Jiten Pathy
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <winpr/crt.h>
#include <freerdp/crypto/er.h>
#include <freerdp/crypto/ber.h>
#include <freerdp/crypto/der.h>
void er_read_length(wStream* s, int* length)
{
BYTE byte;
Stream_Read_UINT8(s, byte);
if (!length)
return;
*length = 0;
if (!s)
return;
if (byte & 0x80)
{
byte &= ~(0x80);
if (byte == 1)
Stream_Read_UINT8(s, *length);
if (byte == 2)
Stream_Read_UINT16_BE(s, *length);
}
else
{
*length = byte;
}
}
/**
* Write er length.
* @param s stream
* @param length length
*/
int er_write_length(wStream* s, int length, BOOL flag)
{
if (flag)
return der_write_length(s, length);
else
return ber_write_length(s, length);
}
int _er_skip_length(int length)
{
if (length > 0x7F)
return 3;
else
return 1;
}
int er_get_content_length(int length)
{
if (length - 1 > 0x7F)
return length - 4;
else
return length - 2;
}
/**
* Read er Universal tag.
* @param s stream
* @param tag er universally-defined tag
* @return
*/
BOOL er_read_universal_tag(wStream* s, BYTE tag, BOOL pc)
{
BYTE byte;
Stream_Read_UINT8(s, byte);
if (byte != (ER_CLASS_UNIV | ER_PC(pc) | (ER_TAG_MASK & tag)))
return FALSE;
return TRUE;
}
/**
* Write er Universal tag.
* @param s stream
* @param tag er universally-defined tag
* @param pc primitive (FALSE) or constructed (TRUE)
*/
void er_write_universal_tag(wStream* s, BYTE tag, BOOL pc)
{
Stream_Write_UINT8(s, (ER_CLASS_UNIV | ER_PC(pc)) | (ER_TAG_MASK & tag));
}
/**
* Read er Application tag.
* @param s stream
* @param tag er application-defined tag
* @param length length
*/
BOOL er_read_application_tag(wStream* s, BYTE tag, int* length)
{
BYTE byte;
if (tag > 30)
{
Stream_Read_UINT8(s, byte);
if (byte != ((ER_CLASS_APPL | ER_CONSTRUCT) | ER_TAG_MASK))
return FALSE;
Stream_Read_UINT8(s, byte);
if (byte != tag)
return FALSE;
er_read_length(s, length);
}
else
{
Stream_Read_UINT8(s, byte);
if (byte != ((ER_CLASS_APPL | ER_CONSTRUCT) | (ER_TAG_MASK & tag)))
return FALSE;
er_read_length(s, length);
}
return TRUE;
}
/**
* Write er Application tag.
* @param s stream
* @param tag er application-defined tag
* @param length length
*/
void er_write_application_tag(wStream* s, BYTE tag, int length, BOOL flag)
{
if (tag > 30)
{
Stream_Write_UINT8(s, (ER_CLASS_APPL | ER_CONSTRUCT) | ER_TAG_MASK);
Stream_Write_UINT8(s, tag);
er_write_length(s, length, flag);
}
else
{
Stream_Write_UINT8(s, (ER_CLASS_APPL | ER_CONSTRUCT) | (ER_TAG_MASK & tag));
er_write_length(s, length, flag);
}
}
BOOL er_read_contextual_tag(wStream* s, BYTE tag, int* length, BOOL pc)
{
BYTE byte;
Stream_Read_UINT8(s, byte);
if (byte != ((ER_CLASS_CTXT | ER_PC(pc)) | (ER_TAG_MASK & tag)))
{
Stream_Rewind(s, 1);
return FALSE;
}
er_read_length(s, length);
return TRUE;
}
int er_write_contextual_tag(wStream* s, BYTE tag, int length, BOOL pc, BOOL flag)
{
Stream_Write_UINT8(s, (ER_CLASS_CTXT | ER_PC(pc)) | (ER_TAG_MASK & tag));
return er_write_length(s, length, flag) + 1;
}
int er_skip_contextual_tag(int length)
{
return _er_skip_length(length) + 1;
}
BOOL er_read_sequence_tag(wStream* s, int* length)
{
BYTE byte;
Stream_Read_UINT8(s, byte);
if (byte != ((ER_CLASS_UNIV | ER_CONSTRUCT) | (ER_TAG_SEQUENCE_OF)))
return FALSE;
er_read_length(s, length);
return TRUE;
}
/**
* Write er SEQUENCE tag.
* @param s stream
* @param length length
*/
int er_write_sequence_tag(wStream* s, int length, BOOL flag)
{
Stream_Write_UINT8(s, (ER_CLASS_UNIV | ER_CONSTRUCT) | (ER_TAG_MASK & ER_TAG_SEQUENCE));
return er_write_length(s, length, flag) + 1;
}
int er_skip_sequence(int length)
{
return 1 + _er_skip_length(length) + length;
}
int er_skip_sequence_tag(int length)
{
return 1 + _er_skip_length(length);
}
BOOL er_read_enumerated(wStream* s, BYTE* enumerated, BYTE count)
{
int length = 0;
er_read_universal_tag(s, ER_TAG_ENUMERATED, FALSE);
er_read_length(s, &length);
if (length == 1)
Stream_Read_UINT8(s, *enumerated);
else
return FALSE;
/* check that enumerated value falls within expected range */
if (*enumerated + 1 > count)
return FALSE;
return TRUE;
}
void er_write_enumerated(wStream* s, BYTE enumerated, BYTE count, BOOL flag)
{
er_write_universal_tag(s, ER_TAG_ENUMERATED, FALSE);
er_write_length(s, 1, flag);
Stream_Write_UINT8(s, enumerated);
}
BOOL er_read_bit_string(wStream* s, int* length, BYTE* padding)
{
er_read_universal_tag(s, ER_TAG_BIT_STRING, FALSE);
er_read_length(s, length);
Stream_Read_UINT8(s, *padding);
return TRUE;
}
BOOL er_write_bit_string_tag(wStream* s, UINT32 length, BYTE padding, BOOL flag)
{
er_write_universal_tag(s, ER_TAG_BIT_STRING, FALSE);
er_write_length(s, length, flag);
Stream_Write_UINT8(s, padding);
return TRUE;
}
BOOL er_read_octet_string(wStream* s, int* length)
{
if(!er_read_universal_tag(s, ER_TAG_OCTET_STRING, FALSE))
return FALSE;
er_read_length(s, length);
return TRUE;
}
/**
* Write a er OCTET_STRING
* @param s stream
* @param oct_str octet string
* @param length string length
*/
void er_write_octet_string(wStream* s, BYTE* oct_str, int length, BOOL flag)
{
er_write_universal_tag(s, ER_TAG_OCTET_STRING, FALSE);
er_write_length(s, length, flag);
Stream_Write(s, oct_str, length);
}
int er_write_octet_string_tag(wStream* s, int length, BOOL flag)
{
er_write_universal_tag(s, ER_TAG_OCTET_STRING, FALSE);
er_write_length(s, length, flag);
return 1 + _er_skip_length(length);
}
int er_skip_octet_string(int length)
{
return 1 + _er_skip_length(length) + length;
}
/**
* Read a er BOOLEAN
* @param s
* @param value
*/
BOOL er_read_BOOL(wStream* s, BOOL* value)
{
int length = 0;
BYTE v;
if (!er_read_universal_tag(s, ER_TAG_BOOLEAN, FALSE))
return FALSE;
er_read_length(s, &length);
if (length != 1)
return FALSE;
Stream_Read_UINT8(s, v);
*value = (v ? TRUE : FALSE);
return TRUE;
}
/**
* Write a er BOOLEAN
* @param s
* @param value
*/
void er_write_BOOL(wStream* s, BOOL value)
{
er_write_universal_tag(s, ER_TAG_BOOLEAN, FALSE);
er_write_length(s, 1, FALSE);
Stream_Write_UINT8(s, (value == TRUE) ? 0xFF : 0);
}
BOOL er_read_integer(wStream* s, UINT32* value)
{
int length = 0;
er_read_universal_tag(s, ER_TAG_INTEGER, FALSE);
er_read_length(s, &length);
if (value == NULL)
{
Stream_Seek(s, length);
return TRUE;
}
if (length == 1)
{
Stream_Read_UINT8(s, *value);
}
else if (length == 2)
{
Stream_Read_UINT16_BE(s, *value);
}
else if (length == 3)
{
BYTE byte;
Stream_Read_UINT8(s, byte);
Stream_Read_UINT16_BE(s, *value);
*value += (byte << 16);
}
else if (length == 4)
{
Stream_Read_UINT32_BE(s, *value);
}
else
{
return FALSE;
}
return TRUE;
}
/**
* Write a er INTEGER
* @param s
* @param value
*/
int er_write_integer(wStream* s, INT32 value)
{
er_write_universal_tag(s, ER_TAG_INTEGER, FALSE);
if (value <= 127 && value >= -128)
{
er_write_length(s, 1, FALSE);
Stream_Write_UINT8(s, value);
return 2;
}
else if (value <= 32767 && value >= -32768)
{
er_write_length(s, 2, FALSE);
Stream_Write_UINT16_BE(s, value);
return 3;
}
else
{
er_write_length(s, 4, FALSE);
Stream_Write_UINT32_BE(s, value);
return 5;
}
return 0;
}
int er_skip_integer(INT32 value)
{
if (value <= 127 && value >= -128)
{
return _er_skip_length(1) + 2;
}
else if (value <= 32767 && value >= -32768)
{
return _er_skip_length(2) + 3;
}
else
{
return _er_skip_length(4) + 5;
}
return 0;
}
BOOL er_read_integer_length(wStream* s, int* length)
{
er_read_universal_tag(s, ER_TAG_INTEGER, FALSE);
er_read_length(s, length);
return TRUE;
}