asner.cxx

pwlib源码库

/*
 * asner.cxx
 *
 * Abstract Syntax Notation 1 Encoding Rules
 *
 * Portable Windows Library
 *
 * Copyright (c) 1993-2002 Equivalence Pty. Ltd.
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.0 (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.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 * The Original Code is Portable Windows Library.
 *
 * The Initial Developer of the Original Code is Equivalence Pty. Ltd.
 *
 * Contributor(s): ______________________________________.
 *
 * $Log: asner.cxx,v $
 * Revision 1.91  2005/06/07 06:25:53  csoutheren
 * Applied patch 1199897 to increase speed of ASN parser debugging output
 * Thanks to Dmitriy <[e-mail]>
 *
 * Revision 1.90  2004/07/12 03:42:22  csoutheren
 * Fixed problem with checking character set constraints too aggressively
 *
 * Revision 1.89  2004/07/12 01:56:10  csoutheren
 * Fixed incorrect asn decoding check
 *
 * Revision 1.88  2004/07/11 14:19:07  csoutheren
 * More bulletproofing of ASN routines against random data attacks
 *
 * Revision 1.87  2004/07/11 12:33:47  csoutheren
 * Added guards against illegal PDU values causing crashes
 *
 * Revision 1.86  2004/04/22 07:54:01  csoutheren
 * Fix problem with VS.net asserting on in isprint when chars outside normal range
 *
 * Revision 1.85  2004/04/18 04:33:37  rjongbloed
 * Changed all operators that return BOOL to return standard type bool. This is primarily
 *   for improved compatibility with std STL usage removing many warnings.
 *
 * Revision 1.84  2004/04/03 08:22:20  csoutheren
 * Remove pseudo-RTTI and replaced with real RTTI
 *
 * Revision 1.83  2004/01/17 09:21:21  csoutheren
 * Added protection against NULL ptr to PASN_Stream::BlockDecode
 *
 * Revision 1.82  2003/08/01 02:11:38  csoutheren
 * Changed to allow easy isolation of PER, BER and XER encoding/decoding routines
 *
 * Revision 1.81  2003/04/28 02:50:33  robertj
 * Fixed problem with spaces in type name, thanks Federico Pinna
 *
 * Revision 1.80  2003/02/26 04:37:21  robertj
 * Tidied some comments
 *
 * Revision 1.79  2003/02/26 01:57:44  robertj
 * Added XML encoding rules to ASN system, thanks Federico Pinna
 *
 * Revision 1.78  2003/01/24 23:43:43  robertj
 * Fixed subtle problems with the use of MAX keyword for unsigned numbers,
 *   should beUINT_MAX not INT_MAX, thanks Stevie Gray for pointing it out.
 *
 * Revision 1.77  2002/12/17 07:00:15  robertj
 * Fixed incorrect encoding of arrays greater than 8192 and less than 16384
 *
 * Revision 1.76  2002/12/13 03:57:17  robertj
 * Fixed crash if enable extension fields beyond the "known" extensions.
 *
 * Revision 1.75  2002/12/02 01:03:33  robertj
 * Fixed bug were if setting the size of a constrained bit string, it
 *   actually sets the size of the underlying byte array correctly.
 *
 * Revision 1.74  2002/11/26 23:29:32  robertj
 * Added missing const to DecodeSubType() function.
 *
 * Revision 1.73  2002/11/22 09:43:32  robertj
 * Fixed encoding of a ASN NULL sequence extension field, eg fastConnectRefused
 *
 * Revision 1.72  2002/11/21 03:46:22  robertj
 * Changed to encode only the minimum number of bits required, this improves
 *   compatibility with some brain dead ASN decoders.
 *
 * Revision 1.71  2002/11/06 22:47:24  robertj
 * Fixed header comment (copyright etc)
 *
 * Revision 1.70  2002/10/31 05:51:10  robertj
 * Changed to use new UTF-8/UCS-2 conversion functions on PString.
 *
 * Revision 1.69  2002/10/29 08:12:44  robertj
 * Fixed MSVC warnings.
 *
 * Revision 1.68  2002/10/29 07:26:45  robertj
 * Fixed subtle bug when encoding or decoding Octet String with 1 or 2 bytes
 *   in it, was not byte aligned correctly.
 *
 * Revision 1.67  2002/09/26 23:53:20  robertj
 * Fixed incorrect asserts in PASN_Enumerated, thanks Platzer Wolfgang
 *
 * Revision 1.66  2002/09/13 08:16:15  robertj
 * Fixed missing line feed when dumping hex octet strings.
 *
 * Revision 1.65  2002/08/06 02:27:58  robertj
 * GNU C++ v3 compatibility.
 *
 * Revision 1.64  2002/07/25 10:52:49  robertj
 * Changes to allow more granularity in PDU dumps, hex output increasing
 *   with increasing trace level.
 *
 * Revision 1.63  2002/06/05 12:29:15  craigs
 * Changes for gcc 3.1
 *
 * Revision 1.62  2002/05/29 01:22:35  robertj
 * Added ability to set object id from unsigned integer arrays.
 *
 * Revision 1.61  2002/05/21 04:23:40  robertj
 * Fixed problem with ASN encoding/decoding unsconstrained negative numbers,
 *
 * Revision 1.60  2002/05/14 08:34:29  robertj
 * Fixed problem encoding unsigned where value==lower bound, thanks Greg Adams.
 *
 * Revision 1.59  2002/05/14 06:59:50  robertj
 * Added more bullet proofing so a malformed PDU cannot cause teh decoder
 *   to try and allocate huge arrays and consume all CPU and memory on a
 *   system. A configurable limit of 100 is set for things like SEQUENCE OF.
 *
 * Revision 1.58  2002/02/08 12:47:19  robertj
 * Fixed incorrect encoding of integer, did not allow for sign bit, thanks Kevin Tran.
 *
 * Revision 1.57  2002/02/01 01:17:36  robertj
 * Fixed bug in encoding empty strings (H.450 issue), thanks Frans Dams, Frank Derks et al.
 *
 * Revision 1.56  2002/01/30 08:40:55  robertj
 * Fixed incorrect decode function in BER string decode, thanks [e-mail]
 *
 * Revision 1.55  2001/12/13 09:13:57  robertj
 * Added function get get oid as a string.
 *
 * Revision 1.54  2001/11/26 03:07:13  robertj
 * Fixed decode of extendable constrained integer types.
 *
 * Revision 1.53  2001/09/14 05:26:11  robertj
 * Fixed problem with assigning a PASN_Choice to itself, thanks Chih-Wei Huang
 *
 * Revision 1.52  2001/09/14 01:59:59  robertj
 * Fixed problem with incorrectly initialised PASN_Choice sub-object.
 *
 * Revision 1.51  2001/08/08 04:19:28  robertj
 * Fixed PString<->BMPString conversion so can have embedded nulls.
 *
 * Revision 1.50  2001/08/07 04:37:03  robertj
 * Simplified &#num; parsing.
 *
 * Revision 1.49  2001/08/07 02:49:05  robertj
 * Fixed incorrect alignment if constrained string upper bound is exactly
 *     16 bits long. thanks Guntram Diehl & Thomas Arimont.
 *
 * Revision 1.48  2001/08/06 09:35:25  robertj
 * Fixed GNU compatibility.
 *
 * Revision 1.47  2001/08/06 09:31:48  robertj
 * Added conversion of BMPString to PString without losing special characters.
 *
 * Revision 1.46  2001/08/06 01:39:02  robertj
 * Added assignement operator with RHS of PASN_BMPString to classes
 *   descended from PASN_BMPString.
 *
 * Revision 1.45  2001/06/14 02:14:12  robertj
 * Added functions to encode and decode another ASN type that is inside
 *   an octet string, useful for ANY or EXTERNAL types etc.
 *
 * Revision 1.44  2001/05/29 00:59:16  robertj
 * Fixed excessive padding on constrained strings.
 *
 * Revision 1.43  2001/05/22 23:37:42  robertj
 * Fixed problem with assigning a constrained string value to itself, which
 *   can occur when changing constraints.
 *
 * Revision 1.42  2001/04/30 10:47:33  robertj
 * Fixed stupid error in last patch.
 *
 * Revision 1.41  2001/04/30 06:47:04  robertj
 * Fixed problem with en/decoding more than 16 extension fields in a sequence.
 *
 * Revision 1.40  2001/04/26 08:15:58  robertj
 * Fixed problem with ASN compile of single constraints on enumerations.
 *
 * Revision 1.39  2001/04/23 05:46:06  robertj
 * Fixed problem with unconstrained PASN_NumericString coding in 8 bits
 *   instead of 4, thanks Chew Kuan.
 *
 * Revision 1.38  2001/04/23 04:40:14  robertj
 * Added ASN standard types GeneralizedTime and UTCTime
 *
 * Revision 1.37  2001/04/12 03:26:59  robertj
 * Fixed PASN_Boolean cosntructor to be compatible with usage in ASN parser.
 * Changed all PASN_xxx types so constructor can take real type as only
 *   parameter. eg PASN_OctetString s = "fred";
 * Changed block encode/decode so does not do a ByteAlign() if zero
 *   length, required for interoperability even though spec implies otherwise..
 *
 * Revision 1.36  2001/01/24 04:37:07  robertj
 * Added more bulletproofing to ASN structures to obey constraints.
 *
 * Revision 1.35  2001/01/03 01:20:13  robertj
 * Fixed error in BlockEncode, should ByteAlign() even on zero length strings.
 *
 * Revision 1.34  2000/10/26 11:09:16  robertj
 * More bullet proofing of PER decoder, changed bit type to be unsigned.
 *
 * Revision 1.33  2000/10/26 01:29:32  robertj
 * Fixed MSVC warning.
 *
 * Revision 1.32  2000/10/25 04:05:38  robertj
 * More bullet proofing of PER decoder.
 *
 * Revision 1.31  2000/09/29 04:11:51  robertj
 * Fixed possible out of range memory access, thanks Petr Par齴ek <[e-mail]>
 *
 * Revision 1.30  2000/02/29 06:32:12  robertj
 * Added ability to remove optional field in sequence, thanks Dave Harvey.
 *
 * Revision 1.29  2000/01/20 06:22:22  robertj
 * Fixed boundary condition error for constrained integer encoding (values 1, 256 etc)
 *
 * Revision 1.28  1999/11/22 23:15:43  robertj
 * Fixed bug in PASN_Choice::Compare(), should make sure choices are the same before comparing.
 *
 * Revision 1.27  1999/08/19 15:43:07  robertj
 * Fixed incorrect size of OID if zero length encoded.
 *
 * Revision 1.26  1999/08/09 13:02:45  robertj
 * dded ASN compiler #defines for backward support of pre GCC 2.9 compilers.
 * Added ASN compiler #defines to reduce its memory footprint.
 *
 * Revision 1.25  1999/08/08 15:45:59  robertj
 * Fixed incorrect encoding of unknown extensions.
 *
 * Revision 1.24  1999/08/05 00:44:28  robertj
 * Fixed PER encoding problems for large integer values.
 *
 * Revision 1.23  1999/07/22 06:48:54  robertj
 * Added comparison operation to base ASN classes and compiled ASN code.
 * Added support for ANY type in ASN parser.
 *
 * Revision 1.22  1999/07/08 08:39:12  robertj
 * Fixed bug when assigning negative number ot cosntrained PASN_Integer
 *
 * Revision 1.21  1999/06/30 08:58:12  robertj
 * Fixed bug in encoding/decoding OID greater than 2.39
 *
 * Revision 1.20  1999/06/17 13:27:09  robertj
 * Fixed bug causing crashes on pass through of unknown extensions.
 *
 * Revision 1.19  1999/06/07 00:31:25  robertj
 * Fixed signed/unsigned problem with number of unknown extensions check.
 *
 * Revision 1.18  1999/04/26 05:58:48  craigs
 * Fixed problems with encoding of extensions
 *
 * Revision 1.17  1999/03/09 08:12:38  robertj
 * Fixed problem with closing a steam encoding twice.
 *
 * Revision 1.16  1999/01/16 01:28:25  robertj
 * Fixed problems with reading stream multiple times.
 *
 * Revision 1.15  1998/11/30 04:50:44  robertj
 * New directory structure
 *
 * Revision 1.14  1998/10/22 04:33:11  robertj
 * Fixed bug in constrained strings and PER, incorrect order of character set.
 *
 * Revision 1.13  1998/09/23 06:21:49  robertj
 * Added open source copyright license.
 *
 * Revision 1.12  1998/05/26 05:29:23  robertj
 * Workaroung for g++ iostream bug.
 *
 * Revision 1.11  1998/05/21 04:58:54  robertj
 * GCC comptaibility.
 *
 * Revision 1.10  1998/05/21 04:26:54  robertj
 * Fixed numerous PER problems.
 *
 * Revision 1.9  1998/05/11 06:01:55  robertj
 * Why did this compile under MSC?
 *
 * Revision 1.8  1998/05/07 05:19:29  robertj
 * Fixed problems with using copy constructor/assignment oeprator on PASN_Objects.
 *
 * Revision 1.7  1998/03/05 12:49:50  robertj
 * MemCheck fixes.
 *
 * Revision 1.6  1998/02/03 06:28:27  robertj
 * Fixed length calculation of integers in BER.
 * Added new function to read a block with minimum number of bytes.
 *
 * Revision 1.5  1998/01/26 01:51:20  robertj
 * Removed uninitialised variable warnings.
 *
 * Revision 1.4  1997/12/18 05:07:56  robertj
 * Fixed bug in choice name display.
 * Added function to get choice discriminator name.
 * Fixed bug in encoding extensions.
 *
 * Revision 1.3  1997/12/11 10:36:22  robertj
 * Support for new ASN parser.
 *
 */

#include <ptlib.h>

#ifdef __GNUC__
#pragma implementation "asner.h"
#endif

#include <ptclib/asner.h>

#if P_EXPAT
#include <ptclib/pxml.h>
#endif

#define new PNEW


static PINDEX MaximumArraySize     = 128;
static PINDEX MaximumStringSize    = 16*1024;
static PINDEX MaximumSetSize       = 512;


static PINDEX CountBits(unsigned range)
{
  switch (range) {
    case 0 :
      return sizeof(unsigned)*8;
    case 1:
      return 1;
  }

  size_t nBits = 0;
  while (nBits < (sizeof(unsigned)*8) && range > (unsigned)(1 << nBits))
    nBits++;
  return nBits;
}

inline BOOL CheckByteOffset(PINDEX offset, PINDEX upper = MaximumStringSize)
{
  // a 1mbit PDU has got to be an error
  return (0 <= offset && offset <= upper);
}

static PINDEX FindNameByValue(const PASN_Names *names, unsigned namesCount, PINDEX value)
{
  if (names != NULL) {
    for (unsigned int i = 0;i < namesCount;i++) {
      if (names[i].value == value)
        return i;
    }
  }
  return P_MAX_INDEX;
}

///////////////////////////////////////////////////////////////////////

PASN_Object::PASN_Object(unsigned theTag, TagClass theTagClass, BOOL extend)
{
  extendable = extend;

  tag = theTag;

  if (theTagClass != DefaultTagClass)
    tagClass = theTagClass;
  else
    tagClass = ContextSpecificTagClass;
}


void PASN_Object::SetTag(unsigned newTag, TagClass tagClass_)
{
  tag = newTag;
  if (tagClass_ != DefaultTagClass)
    tagClass = tagClass_;
}


PINDEX PASN_Object::GetObjectLength() const
{
  PINDEX len = 1;

  if (tag >= 31)
    len += (CountBits(tag)+6)/7;

  PINDEX dataLen = GetDataLength();
  if (dataLen < 128)
    len++;
  else
    len += (CountBits(dataLen)+7)/8 + 1;

  return len + dataLen;
}


void PASN_Object::SetConstraintBounds(ConstraintType, int, unsigned)
{
}


void PASN_Object::SetCharacterSet(ConstraintType, const char *)
{
}


void PASN_Object::SetCharacterSet(ConstraintType, unsigned, unsigned)
{
}


PINDEX PASN_Object::GetMaximumArraySize()
{
  return MaximumArraySize;
}


void PASN_Object::SetMaximumArraySize(PINDEX sz)
{
  MaximumArraySize = sz;
}


PINDEX PASN_Object::GetMaximumStringSize()
{
  return MaximumStringSize;
}


void PASN_Object::SetMaximumStringSize(PINDEX sz)
{
  MaximumStringSize = sz;
}


///////////////////////////////////////////////////////////////////////

PASN_ConstrainedObject::PASN_ConstrainedObject(unsigned tag, TagClass tagClass)
  : PASN_Object(tag, tagClass)
{
  constraint = Unconstrained;
  lowerLimit = 0;
  upperLimit =  UINT_MAX;
}


void PASN_ConstrainedObject::SetConstraintBounds(ConstraintType ctype,
                                                 int lower, unsigned upper)
{
  constraint = ctype;
  if (constraint == Unconstrained) {
    lower = 0;
    upper = UINT_MAX;
  }

  extendable = ctype == ExtendableConstraint;
//  if ((lower >= 0 && upper < 0x7fffffff) ||
//     (lower < 0 && (unsigned)lower <= upper)) {
    lowerLimit = lower;
    upperLimit = upper;
//  }
}


///////////////////////////////////////////////////////////////////////

PASN_Null::PASN_Null(unsigned tag, TagClass tagClass)
  : PASN_Object(tag, tagClass)
{
}


PObject::Comparison PASN_Null::Compare(const PObject & obj) const
{
  PAssert(PIsDescendant(&obj, PASN_Null), PInvalidCast);
  return EqualTo;
}


PObject * PASN_Null::Clone() const
{
  PAssert(IsClass(PASN_Null::Class()), PInvalidCast);
  return new PASN_Null(*this);
}


void PASN_Null::PrintOn(ostream & strm) const
{
  strm << "<<null>>";
}


PString PASN_Null::GetTypeAsString() const
{
  return "Null";
}


PINDEX PASN_Null::GetDataLength() const
{
  return 0;
}


BOOL PASN_Null::Decode(PASN_Stream & strm)
{
  return strm.NullDecode(*this);
}


void PASN_Null::Encode(PASN_Stream & strm) const
{
  strm.NullEncode(*this);
}


///////////////////////////////////////////////////////////////////////

PASN_Boolean::PASN_Boolean(BOOL val)
  : PASN_Object(UniversalBoolean, UniversalTagClass)
{
  value = val;
}


PASN_Boolean::PASN_Boolean(unsigned tag, TagClass tagClass, BOOL val)
  : PASN_Object(tag, tagClass)
{
  value = val;
}


PObject::Comparison PASN_Boolean::Compare(const PObject & obj) const
{
  PAssert(PIsDescendant(&obj, PASN_Boolean), PInvalidCast);
  return value == ((const PASN_Boolean &)obj).value ? EqualTo : GreaterThan;
}


PObject * PASN_Boolean::Clone() const