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asn.cpp

00001 // asn.cpp - written and placed in the public domain by Wei Dai
00002 
00003 #include "pch.h"
00004 
00005 #ifndef CRYPTOPP_IMPORTS
00006 
00007 #include "asn.h"
00008 
00009 #include <iomanip>
00010 #include <time.h>
00011 
00012 NAMESPACE_BEGIN(CryptoPP)
00013 USING_NAMESPACE(std)
00014 
00015 /// DER Length
00016 unsigned int DERLengthEncode(BufferedTransformation &bt, unsigned int length)
00017 {
00018         unsigned int i=0;
00019         if (length <= 0x7f)
00020         {
00021                 bt.Put(byte(length));
00022                 i++;
00023         }
00024         else
00025         {
00026                 bt.Put(byte(BytePrecision(length) | 0x80));
00027                 i++;
00028                 for (int j=BytePrecision(length); j; --j)
00029                 {
00030                         bt.Put(byte(length >> (j-1)*8));
00031                         i++;
00032                 }
00033         }
00034         return i;
00035 }
00036 
00037 bool BERLengthDecode(BufferedTransformation &bt, unsigned int &length, bool &definiteLength)
00038 {
00039         byte b;
00040 
00041         if (!bt.Get(b))
00042                 return false;
00043 
00044         if (!(b & 0x80))
00045         {
00046                 definiteLength = true;
00047                 length = b;
00048         }
00049         else
00050         {
00051                 unsigned int lengthBytes = b & 0x7f;
00052 
00053                 if (lengthBytes == 0)
00054                 {
00055                         definiteLength = false;
00056                         return true;
00057                 }
00058 
00059                 definiteLength = true;
00060                 length = 0;
00061                 while (lengthBytes--)
00062                 {
00063                         if (length >> (8*(sizeof(length)-1)))
00064                                 BERDecodeError();       // length about to overflow
00065 
00066                         if (!bt.Get(b))
00067                                 return false;
00068 
00069                         length = (length << 8) | b;
00070                 }
00071         }
00072         return true;
00073 }
00074 
00075 bool BERLengthDecode(BufferedTransformation &bt, unsigned int &length)
00076 {
00077         bool definiteLength;
00078         if (!BERLengthDecode(bt, length, definiteLength))
00079                 BERDecodeError();
00080         return definiteLength;
00081 }
00082 
00083 void DEREncodeNull(BufferedTransformation &out)
00084 {
00085         out.Put(TAG_NULL);
00086         out.Put(0);
00087 }
00088 
00089 void BERDecodeNull(BufferedTransformation &in)
00090 {
00091         byte b;
00092         if (!in.Get(b) || b != TAG_NULL)
00093                 BERDecodeError();
00094         unsigned int length;
00095         if (!BERLengthDecode(in, length) || length != 0)
00096                 BERDecodeError();
00097 }
00098 
00099 /// ASN Strings
00100 unsigned int DEREncodeOctetString(BufferedTransformation &bt, const byte *str, unsigned int strLen)
00101 {
00102         bt.Put(OCTET_STRING);
00103         unsigned int lengthBytes = DERLengthEncode(bt, strLen);
00104         bt.Put(str, strLen);
00105         return 1+lengthBytes+strLen;
00106 }
00107 
00108 unsigned int DEREncodeOctetString(BufferedTransformation &bt, const SecByteBlock &str)
00109 {
00110         return DEREncodeOctetString(bt, str.begin(), str.size());
00111 }
00112 
00113 unsigned int BERDecodeOctetString(BufferedTransformation &bt, SecByteBlock &str)
00114 {
00115         byte b;
00116         if (!bt.Get(b) || b != OCTET_STRING)
00117                 BERDecodeError();
00118 
00119         unsigned int bc;
00120         if (!BERLengthDecode(bt, bc))
00121                 BERDecodeError();
00122 
00123         str.resize(bc);
00124         if (bc != bt.Get(str, bc))
00125                 BERDecodeError();
00126         return bc;
00127 }
00128 
00129 unsigned int BERDecodeOctetString(BufferedTransformation &bt, BufferedTransformation &str)
00130 {
00131         byte b;
00132         if (!bt.Get(b) || b != OCTET_STRING)
00133                 BERDecodeError();
00134 
00135         unsigned int bc;
00136         if (!BERLengthDecode(bt, bc))
00137                 BERDecodeError();
00138 
00139         bt.TransferTo(str, bc);
00140         return bc;
00141 }
00142 
00143 unsigned int DEREncodeTextString(BufferedTransformation &bt, const std::string &str, byte asnTag)
00144 {
00145         bt.Put(asnTag);
00146         unsigned int lengthBytes = DERLengthEncode(bt, str.size());
00147         bt.Put((const byte *)str.data(), str.size());
00148         return 1+lengthBytes+str.size();
00149 }
00150 
00151 unsigned int BERDecodeTextString(BufferedTransformation &bt, std::string &str, byte asnTag)
00152 {
00153         byte b;
00154         if (!bt.Get(b) || b != asnTag)
00155                 BERDecodeError();
00156 
00157         unsigned int bc;
00158         if (!BERLengthDecode(bt, bc))
00159                 BERDecodeError();
00160 
00161         SecByteBlock temp(bc);
00162         if (bc != bt.Get(temp, bc))
00163                 BERDecodeError();
00164         str.assign((char *)temp.begin(), bc);
00165         return bc;
00166 }
00167 
00168 /// ASN BitString
00169 unsigned int DEREncodeBitString(BufferedTransformation &bt, const byte *str, unsigned int strLen, unsigned int unusedBits)
00170 {
00171         bt.Put(BIT_STRING);
00172         unsigned int lengthBytes = DERLengthEncode(bt, strLen+1);
00173         bt.Put((byte)unusedBits);
00174         bt.Put(str, strLen);
00175         return 2+lengthBytes+strLen;
00176 }
00177 
00178 unsigned int BERDecodeBitString(BufferedTransformation &bt, SecByteBlock &str, unsigned int &unusedBits)
00179 {
00180         byte b;
00181         if (!bt.Get(b) || b != BIT_STRING)
00182                 BERDecodeError();
00183 
00184         unsigned int bc;
00185         if (!BERLengthDecode(bt, bc))
00186                 BERDecodeError();
00187 
00188         byte unused;
00189         if (!bt.Get(unused))
00190                 BERDecodeError();
00191         unusedBits = unused;
00192         str.resize(bc-1);
00193         if ((bc-1) != bt.Get(str, bc-1))
00194                 BERDecodeError();
00195         return bc-1;
00196 }
00197 
00198 void OID::EncodeValue(BufferedTransformation &bt, unsigned long v)
00199 {
00200         for (unsigned int i=RoundUpToMultipleOf(STDMAX(7U,BitPrecision(v)), 7U)-7; i != 0; i-=7)
00201                 bt.Put((byte)(0x80 | ((v >> i) & 0x7f)));
00202         bt.Put((byte)(v & 0x7f));
00203 }
00204 
00205 unsigned int OID::DecodeValue(BufferedTransformation &bt, unsigned long &v)
00206 {
00207         byte b;
00208         unsigned int i=0;
00209         v = 0;
00210         while (true)
00211         {
00212                 if (!bt.Get(b))
00213                         BERDecodeError();
00214                 i++;
00215                 v <<= 7;
00216                 v += b & 0x7f;
00217                 if (!(b & 0x80))
00218                         return i;
00219         }
00220 }
00221 
00222 void OID::DEREncode(BufferedTransformation &bt) const
00223 {
00224         assert(m_values.size() >= 2);
00225         ByteQueue temp;
00226         temp.Put(byte(m_values[0] * 40 + m_values[1]));
00227         for (unsigned int i=2; i<m_values.size(); i++)
00228                 EncodeValue(temp, m_values[i]);
00229         bt.Put(OBJECT_IDENTIFIER);
00230         DERLengthEncode(bt, temp.CurrentSize());
00231         temp.TransferTo(bt);
00232 }
00233 
00234 void OID::BERDecode(BufferedTransformation &bt)
00235 {
00236         byte b;
00237         if (!bt.Get(b) || b != OBJECT_IDENTIFIER)
00238                 BERDecodeError();
00239 
00240         unsigned int length;
00241         if (!BERLengthDecode(bt, length) || length < 1)
00242                 BERDecodeError();
00243 
00244         if (!bt.Get(b))
00245                 BERDecodeError();
00246         
00247         length--;
00248         m_values.resize(2);
00249         m_values[0] = b / 40;
00250         m_values[1] = b % 40;
00251 
00252         while (length > 0)
00253         {
00254                 unsigned long v;
00255                 unsigned int valueLen = DecodeValue(bt, v);
00256                 if (valueLen > length)
00257                         BERDecodeError();
00258                 m_values.push_back(v);
00259                 length -= valueLen;
00260         }
00261 }
00262 
00263 void OID::BERDecodeAndCheck(BufferedTransformation &bt) const
00264 {
00265         OID oid(bt);
00266         if (*this != oid)
00267                 BERDecodeError();
00268 }
00269 
00270 inline BufferedTransformation & EncodedObjectFilter::CurrentTarget()
00271 {
00272         if (m_flags & PUT_OBJECTS) 
00273                 return *AttachedTransformation();
00274         else
00275                 return TheBitBucket();
00276 }
00277 
00278 void EncodedObjectFilter::Put(const byte *inString, unsigned int length)
00279 {
00280         if (m_nCurrentObject == m_nObjects)
00281         {
00282                 AttachedTransformation()->Put(inString, length);
00283                 return;
00284         }
00285 
00286         LazyPutter lazyPutter(m_queue, inString, length);
00287 
00288         while (m_queue.AnyRetrievable())
00289         {
00290                 switch (m_state)
00291                 {
00292                 case IDENTIFIER:
00293                         if (!m_queue.Get(m_id))
00294                                 return;
00295                         m_queue.TransferTo(CurrentTarget(), 1);
00296                         m_state = LENGTH;       // fall through
00297                 case LENGTH:
00298                 {
00299                         byte b;
00300                         if (m_level > 0 && m_id == 0 && m_queue.Peek(b) && b == 0)
00301                         {
00302                                 m_queue.TransferTo(CurrentTarget(), 1);
00303                                 m_level--;
00304                                 m_state = IDENTIFIER;
00305                                 break;
00306                         }
00307                         ByteQueue::Walker walker(m_queue);
00308                         bool definiteLength;
00309                         if (!BERLengthDecode(walker, m_lengthRemaining, definiteLength))
00310                                 return;
00311                         m_queue.TransferTo(CurrentTarget(), walker.GetCurrentPosition());
00312                         if (!((m_id & CONSTRUCTED) || definiteLength))
00313                                 BERDecodeError();
00314                         if (!definiteLength)
00315                         {
00316                                 if (!(m_id & CONSTRUCTED))
00317                                         BERDecodeError();
00318                                 m_level++;
00319                                 m_state = IDENTIFIER;
00320                                 break;
00321                         }
00322                         m_state = BODY;         // fall through
00323                 }
00324                 case BODY:
00325                         m_lengthRemaining -= m_queue.TransferTo(CurrentTarget(), m_lengthRemaining);
00326 
00327                         if (m_lengthRemaining == 0)
00328                                 m_state = IDENTIFIER;
00329                 }
00330 
00331                 if (m_state == IDENTIFIER && m_level == 0)
00332                 {
00333                         // just finished processing a level 0 object
00334                         ++m_nCurrentObject;
00335 
00336                         if (m_flags & PUT_MESSANGE_END_AFTER_EACH_OBJECT)
00337                                 AttachedTransformation()->MessageEnd();
00338 
00339                         if (m_nCurrentObject == m_nObjects)
00340                         {
00341                                 if (m_flags & PUT_MESSANGE_END_AFTER_ALL_OBJECTS)
00342                                         AttachedTransformation()->MessageEnd();
00343 
00344                                 if (m_flags & PUT_MESSANGE_SERIES_END_AFTER_ALL_OBJECTS)
00345                                         AttachedTransformation()->MessageSeriesEnd();
00346 
00347                                 m_queue.TransferAllTo(*AttachedTransformation());
00348                                 return;
00349                         }
00350                 }
00351         }
00352 }
00353 
00354 BERGeneralDecoder::BERGeneralDecoder(BufferedTransformation &inQueue, byte asnTag)
00355         : m_inQueue(inQueue), m_finished(false)
00356 {
00357         byte b;
00358         if (!m_inQueue.Get(b) || b != asnTag)
00359                 BERDecodeError();
00360 
00361         m_definiteLength = BERLengthDecode(m_inQueue, m_length);
00362 }
00363 
00364 BERGeneralDecoder::BERGeneralDecoder(BERGeneralDecoder &inQueue, byte asnTag)
00365         : m_inQueue(inQueue), m_finished(false)
00366 {
00367         byte b;
00368         if (!m_inQueue.Get(b) || b != asnTag)
00369                 BERDecodeError();
00370 
00371         m_definiteLength = BERLengthDecode(m_inQueue, m_length);
00372         if (!m_definiteLength && !(asnTag & CONSTRUCTED))
00373                 BERDecodeError();       // cannot be primitive have indefinite length
00374 }
00375 
00376 BERGeneralDecoder::~BERGeneralDecoder()
00377 {
00378         try     // avoid throwing in constructor
00379         {
00380                 if (!m_finished)
00381                         MessageEnd();
00382         }
00383         catch (...)
00384         {
00385         }
00386 }
00387 
00388 bool BERGeneralDecoder::EndReached() const
00389 {
00390         if (m_definiteLength)
00391                 return m_length == 0;
00392         else
00393         {       // check end-of-content octets
00394                 word16 i;
00395                 return (m_inQueue.PeekWord16(i)==2 && i==0);
00396         }
00397 }
00398 
00399 byte BERGeneralDecoder::PeekByte() const
00400 {
00401         byte b;
00402         if (!Peek(b))
00403                 BERDecodeError();
00404         return b;
00405 }
00406 
00407 void BERGeneralDecoder::CheckByte(byte check)
00408 {
00409         byte b;
00410         if (!Get(b) || b != check)
00411                 BERDecodeError();
00412 }
00413 
00414 void BERGeneralDecoder::MessageEnd()
00415 {
00416         m_finished = true;
00417         if (m_definiteLength)
00418         {
00419                 if (m_length != 0)
00420                         BERDecodeError();
00421         }
00422         else
00423         {       // remove end-of-content octets
00424                 word16 i;
00425                 if (m_inQueue.GetWord16(i) != 2 || i != 0)
00426                         BERDecodeError();
00427         }
00428 }
00429 
00430 unsigned int BERGeneralDecoder::TransferTo2(BufferedTransformation &target, unsigned long &transferBytes, const std::string &channel, bool blocking)
00431 {
00432         if (m_definiteLength && transferBytes > m_length)
00433                 transferBytes = m_length;
00434         unsigned int blockedBytes = m_inQueue.TransferTo2(target, transferBytes, channel, blocking);
00435         ReduceLength(transferBytes);
00436         return blockedBytes;
00437 }
00438 
00439 unsigned int BERGeneralDecoder::CopyRangeTo2(BufferedTransformation &target, unsigned long &begin, unsigned long end, const std::string &channel, bool blocking) const
00440 {
00441         if (m_definiteLength)
00442                 end = STDMIN((unsigned long)m_length, end);
00443         return m_inQueue.CopyRangeTo2(target, begin, end, channel, blocking);
00444 }
00445 
00446 unsigned int BERGeneralDecoder::ReduceLength(unsigned int delta)
00447 {
00448         if (m_definiteLength)
00449         {
00450                 if (m_length < delta)
00451                         BERDecodeError();
00452                 m_length -= delta;
00453         }
00454         return delta;
00455 }
00456 
00457 DERGeneralEncoder::DERGeneralEncoder(BufferedTransformation &outQueue, byte asnTag)
00458         : m_outQueue(outQueue), m_finished(false), m_asnTag(asnTag)
00459 {
00460 }
00461 
00462 DERGeneralEncoder::DERGeneralEncoder(DERGeneralEncoder &outQueue, byte asnTag)
00463         : m_outQueue(outQueue), m_finished(false), m_asnTag(asnTag)
00464 {
00465 }
00466 
00467 DERGeneralEncoder::~DERGeneralEncoder()
00468 {
00469         try     // avoid throwing in constructor
00470         {
00471                 if (!m_finished)
00472                         MessageEnd();
00473         }
00474         catch (...)
00475         {
00476         }
00477 }
00478 
00479 void DERGeneralEncoder::MessageEnd()
00480 {
00481         m_finished = true;
00482         unsigned int length = (unsigned int)CurrentSize();
00483         m_outQueue.Put(m_asnTag);
00484         DERLengthEncode(m_outQueue, length);
00485         TransferTo(m_outQueue);
00486 }
00487 
00488 // *************************************************************
00489 
00490 void X509PublicKey::BERDecode(BufferedTransformation &bt)
00491 {
00492         BERSequenceDecoder subjectPublicKeyInfo(bt);
00493                 BERSequenceDecoder algorithm(subjectPublicKeyInfo);
00494                         GetAlgorithmID().BERDecodeAndCheck(algorithm);
00495                         bool parametersPresent = algorithm.EndReached() ? false : BERDecodeAlgorithmParameters(algorithm);
00496                 algorithm.MessageEnd();
00497 
00498                 BERGeneralDecoder subjectPublicKey(subjectPublicKeyInfo, BIT_STRING);
00499                         subjectPublicKey.CheckByte(0);  // unused bits
00500                         BERDecodeKey2(subjectPublicKey, parametersPresent, subjectPublicKey.RemainingLength());
00501                 subjectPublicKey.MessageEnd();
00502         subjectPublicKeyInfo.MessageEnd();
00503 }
00504 
00505 void X509PublicKey::DEREncode(BufferedTransformation &bt) const
00506 {
00507         DERSequenceEncoder subjectPublicKeyInfo(bt);
00508 
00509                 DERSequenceEncoder algorithm(subjectPublicKeyInfo);
00510                         GetAlgorithmID().DEREncode(algorithm);
00511                         DEREncodeAlgorithmParameters(algorithm);
00512                 algorithm.MessageEnd();
00513 
00514                 DERGeneralEncoder subjectPublicKey(subjectPublicKeyInfo, BIT_STRING);
00515                         subjectPublicKey.Put(0);        // unused bits
00516                         DEREncodeKey(subjectPublicKey);
00517                 subjectPublicKey.MessageEnd();
00518 
00519         subjectPublicKeyInfo.MessageEnd();
00520 }
00521 
00522 void PKCS8PrivateKey::BERDecode(BufferedTransformation &bt)
00523 {
00524         BERSequenceDecoder privateKeyInfo(bt);
00525                 word32 version;
00526                 BERDecodeUnsigned<word32>(privateKeyInfo, version, INTEGER, 0, 0);      // check version
00527 
00528                 BERSequenceDecoder algorithm(privateKeyInfo);
00529                         GetAlgorithmID().BERDecodeAndCheck(algorithm);
00530                         bool parametersPresent = BERDecodeAlgorithmParameters(algorithm);
00531                 algorithm.MessageEnd();
00532 
00533                 BERGeneralDecoder octetString(privateKeyInfo, OCTET_STRING);
00534                         BERDecodeKey2(octetString, parametersPresent, privateKeyInfo.RemainingLength());
00535                 octetString.MessageEnd();
00536 
00537                 BERDecodeOptionalAttributes(privateKeyInfo);
00538         privateKeyInfo.MessageEnd();
00539 }
00540 
00541 void PKCS8PrivateKey::DEREncode(BufferedTransformation &bt) const
00542 {
00543         DERSequenceEncoder privateKeyInfo(bt);
00544                 DEREncodeUnsigned<word32>(privateKeyInfo, 0);   // version
00545 
00546                 DERSequenceEncoder algorithm(privateKeyInfo);
00547                         GetAlgorithmID().DEREncode(algorithm);
00548                         DEREncodeAlgorithmParameters(algorithm);
00549                 algorithm.MessageEnd();
00550 
00551                 DERGeneralEncoder octetString(privateKeyInfo, OCTET_STRING);
00552                         DEREncodeKey(octetString);
00553                 octetString.MessageEnd();
00554 
00555                 DEREncodeOptionalAttributes(privateKeyInfo);
00556         privateKeyInfo.MessageEnd();
00557 }
00558 
00559 NAMESPACE_END
00560 
00561 #endif

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