LibreOffice Module oox (master)  1
binarycodec.cxx
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19 
20 #include "oox/core/binarycodec.hxx"
21 
22 #include <algorithm>
23 #include <string.h>
25 
26 #include <osl/diagnose.h>
29 
30 using namespace ::com::sun::star;
31 
32 namespace oox {
33 namespace core {
34 
35 namespace {
36 
38 template< typename Type >
39 inline void lclRotateLeft( Type& rnValue, size_t nBits )
40 {
41  OSL_ENSURE( nBits < sizeof( Type ) * 8, "lclRotateLeft - rotation count overflow" );
42  rnValue = static_cast< Type >( (rnValue << nBits) | (rnValue >> (sizeof( Type ) * 8 - nBits)) );
43 }
44 
46 template< typename Type >
47 inline void lclRotateLeft( Type& rnValue, size_t nBits, size_t nWidth )
48 {
49  OSL_ENSURE( (nBits < nWidth) && (nWidth < sizeof( Type ) * 8), "lclRotateLeft - rotation count overflow" );
50  Type nMask = static_cast< Type >( (1UL << nWidth) - 1 );
51  rnValue = static_cast< Type >(
52  ((rnValue << nBits) | ((rnValue & nMask) >> (nWidth - nBits))) & nMask );
53 }
54 
55 sal_Int32 lclGetLen( const sal_uInt8* pnPassData, sal_Int32 nBufferSize )
56 {
57  sal_Int32 nLen = 0;
58  while( (nLen < nBufferSize) && pnPassData[ nLen ] ) ++nLen;
59  return nLen;
60 }
61 
62 sal_uInt16 lclGetKey( const sal_uInt8* pnPassData, sal_Int32 nBufferSize )
63 {
64  sal_Int32 nLen = lclGetLen( pnPassData, nBufferSize );
65  if( nLen <= 0 ) return 0;
66 
67  sal_uInt16 nKey = 0;
68  sal_uInt16 nKeyBase = 0x8000;
69  sal_uInt16 nKeyEnd = 0xFFFF;
70  const sal_uInt8* pnChar = pnPassData + nLen - 1;
71  for( sal_Int32 nIndex = 0; nIndex < nLen; ++nIndex, --pnChar )
72  {
73  sal_uInt8 cChar = *pnChar & 0x7F;
74  for( size_t nBit = 0; nBit < 8; ++nBit )
75  {
76  lclRotateLeft( nKeyBase, 1 );
77  if( nKeyBase & 1 ) nKeyBase ^= 0x1020;
78  if( cChar & 1 ) nKey ^= nKeyBase;
79  cChar >>= 1;
80  lclRotateLeft( nKeyEnd, 1 );
81  if( nKeyEnd & 1 ) nKeyEnd ^= 0x1020;
82  }
83  }
84  return nKey ^ nKeyEnd;
85 }
86 
87 sal_uInt16 lclGetHash( const sal_uInt8* pnPassData, sal_Int32 nBufferSize )
88 {
89  sal_Int32 nLen = lclGetLen( pnPassData, nBufferSize );
90 
91  sal_uInt16 nHash = static_cast< sal_uInt16 >( nLen );
92  if( nLen > 0 )
93  nHash ^= 0xCE4B;
94 
95  const sal_uInt8* pnChar = pnPassData;
96  for( sal_Int32 nIndex = 0; nIndex < nLen; ++nIndex, ++pnChar )
97  {
98  sal_uInt16 cChar = *pnChar;
99  size_t nRot = static_cast< size_t >( (nIndex + 1) % 15 );
100  lclRotateLeft( cChar, nRot, 15 );
101  nHash ^= cChar;
102  }
103  return nHash;
104 }
105 
106 } // namespace
107 
108 sal_uInt16 CodecHelper::getPasswordHash( const AttributeList& rAttribs, sal_Int32 nElement )
109 {
110  sal_Int32 nPasswordHash = rAttribs.getIntegerHex( nElement, 0 );
111  OSL_ENSURE( (0 <= nPasswordHash) && (nPasswordHash <= SAL_MAX_UINT16), "CodecHelper::getPasswordHash - invalid password hash" );
112  return static_cast< sal_uInt16 >( ((0 <= nPasswordHash) && (nPasswordHash <= SAL_MAX_UINT16)) ? nPasswordHash : 0 );
113 }
114 
116  meCodecType( eCodecType ),
117  mnOffset( 0 ),
118  mnBaseKey( 0 ),
119  mnHash( 0 )
120 {
121  (void)memset( mpnKey, 0, sizeof( mpnKey ) );
122 }
123 
125 {
126  (void)memset( mpnKey, 0, sizeof( mpnKey ) );
127  mnBaseKey = mnHash = 0;
128 }
129 
130 void BinaryCodec_XOR::initKey( const sal_uInt8 pnPassData[ 16 ] )
131 {
132  // calculate base key and hash from passed password
133  mnBaseKey = lclGetKey( pnPassData, 16 );
134  mnHash = lclGetHash( pnPassData, 16 );
135 
136  static const sal_uInt8 spnFillChars[] =
137  {
138  0xBB, 0xFF, 0xFF, 0xBA,
139  0xFF, 0xFF, 0xB9, 0x80,
140  0x00, 0xBE, 0x0F, 0x00,
141  0xBF, 0x0F, 0x00
142  };
143 
144  (void)memcpy( mpnKey, pnPassData, 16 );
145  sal_Int32 nIndex;
146  sal_Int32 nLen = lclGetLen( pnPassData, 16 );
147  const sal_uInt8* pnFillChar = spnFillChars;
148  for( nIndex = nLen; nIndex < static_cast< sal_Int32 >( sizeof( mpnKey ) ); ++nIndex, ++pnFillChar )
149  mpnKey[ nIndex ] = *pnFillChar;
150 
151  // rotation of key values is application dependent
152  size_t nRotateSize = 0;
153  switch( meCodecType )
154  {
155  case CODEC_WORD: nRotateSize = 7; break;
156  case CODEC_EXCEL: nRotateSize = 2; break;
157  // compiler will warn, if new codec type is introduced and not handled here
158  }
159 
160  // use little-endian base key to create key array
161  sal_uInt8 pnBaseKeyLE[ 2 ];
162  pnBaseKeyLE[ 0 ] = static_cast< sal_uInt8 >( mnBaseKey );
163  pnBaseKeyLE[ 1 ] = static_cast< sal_uInt8 >( mnBaseKey >> 8 );
164  sal_uInt8* pnKeyChar = mpnKey;
165  for( nIndex = 0; nIndex < static_cast< sal_Int32 >( sizeof( mpnKey ) ); ++nIndex, ++pnKeyChar )
166  {
167  *pnKeyChar ^= pnBaseKeyLE[ nIndex & 1 ];
168  lclRotateLeft( *pnKeyChar, nRotateSize );
169  }
170 }
171 
172 bool BinaryCodec_XOR::initCodec( const uno::Sequence< beans::NamedValue >& aData )
173 {
174  bool bResult = false;
175 
176  ::comphelper::SequenceAsHashMap aHashData( aData );
177  uno::Sequence< sal_Int8 > aKey = aHashData.getUnpackedValueOrDefault("XOR95EncryptionKey", uno::Sequence< sal_Int8 >() );
178 
179  if ( aKey.getLength() == 16 )
180  {
181  (void)memcpy( mpnKey, aKey.getConstArray(), 16 );
182  bResult = true;
183 
184  mnBaseKey = (sal_uInt16)aHashData.getUnpackedValueOrDefault("XOR95BaseKey", (sal_Int16)0 );
185  mnHash = (sal_uInt16)aHashData.getUnpackedValueOrDefault("XOR95PasswordHash", (sal_Int16)0 );
186  }
187  else
188  OSL_FAIL( "Unexpected key size!\n" );
189 
190  return bResult;
191 }
192 
193 uno::Sequence< beans::NamedValue > BinaryCodec_XOR::getEncryptionData()
194 {
196  aHashData[ OUString("XOR95EncryptionKey") ] <<= uno::Sequence<sal_Int8>( (sal_Int8*)mpnKey, 16 );
197  aHashData[ OUString("XOR95BaseKey") ] <<= (sal_Int16)mnBaseKey;
198  aHashData[ OUString("XOR95PasswordHash") ] <<= (sal_Int16)mnHash;
199 
200  return aHashData.getAsConstNamedValueList();
201 }
202 
203 bool BinaryCodec_XOR::verifyKey( sal_uInt16 nKey, sal_uInt16 nHash ) const
204 {
205  return (nKey == mnBaseKey) && (nHash == mnHash);
206 }
207 
209 {
210  mnOffset = 0;
211 }
212 
213 bool BinaryCodec_XOR::decode( sal_uInt8* pnDestData, const sal_uInt8* pnSrcData, sal_Int32 nBytes )
214 {
215  const sal_uInt8* pnCurrKey = mpnKey + mnOffset;
216  const sal_uInt8* pnKeyLast = mpnKey + 0x0F;
217 
218  // switch/case outside of the for loop (performance)
219  const sal_uInt8* pnSrcDataEnd = pnSrcData + nBytes;
220  switch( meCodecType )
221  {
222  case CODEC_WORD:
223  {
224  for( ; pnSrcData < pnSrcDataEnd; ++pnSrcData, ++pnDestData )
225  {
226  sal_uInt8 nData = *pnSrcData ^ *pnCurrKey;
227  if( (*pnSrcData != 0) && (nData != 0) )
228  *pnDestData = nData;
229  if( pnCurrKey < pnKeyLast ) ++pnCurrKey; else pnCurrKey = mpnKey;
230  }
231  }
232  break;
233  case CODEC_EXCEL:
234  {
235  for( ; pnSrcData < pnSrcDataEnd; ++pnSrcData, ++pnDestData )
236  {
237  *pnDestData = *pnSrcData;
238  lclRotateLeft( *pnDestData, 3 );
239  *pnDestData ^= *pnCurrKey;
240  if( pnCurrKey < pnKeyLast ) ++pnCurrKey; else pnCurrKey = mpnKey;
241  }
242  }
243  break;
244  // compiler will warn, if new codec type is introduced and not handled here
245  }
246 
247  // update offset and leave
248  return skip( nBytes );
249 }
250 
251 bool BinaryCodec_XOR::skip( sal_Int32 nBytes )
252 {
253  mnOffset = static_cast< sal_Int32 >( (mnOffset + nBytes) & 0x0F );
254  return true;
255 }
256 
258 {
259  mhCipher = rtl_cipher_create( rtl_Cipher_AlgorithmARCFOUR, rtl_Cipher_ModeStream );
260  OSL_ENSURE( mhCipher != 0, "BinaryCodec_RCF::BinaryCodec_RCF - cannot create cipher" );
261 
262  mhDigest = rtl_digest_create( rtl_Digest_AlgorithmMD5 );
263  OSL_ENSURE( mhDigest != 0, "BinaryCodec_RCF::BinaryCodec_RCF - cannot create digest" );
264 
265  (void)memset( mpnDigestValue, 0, sizeof( mpnDigestValue ) );
266  (void)memset (mpnUnique, 0, sizeof(mpnUnique));
267 }
268 
270 {
271  (void)memset( mpnDigestValue, 0, sizeof( mpnDigestValue ) );
272  (void)memset (mpnUnique, 0, sizeof(mpnUnique));
273  rtl_digest_destroy( mhDigest );
274  rtl_cipher_destroy( mhCipher );
275 }
276 
277 bool BinaryCodec_RCF::initCodec( const uno::Sequence< beans::NamedValue >& aData )
278 {
279  bool bResult = false;
280 
281  ::comphelper::SequenceAsHashMap aHashData( aData );
282  uno::Sequence< sal_Int8 > aKey = aHashData.getUnpackedValueOrDefault("STD97EncryptionKey", uno::Sequence< sal_Int8 >() );
283 
284  if ( aKey.getLength() == RTL_DIGEST_LENGTH_MD5 )
285  {
286  (void)memcpy( mpnDigestValue, aKey.getConstArray(), RTL_DIGEST_LENGTH_MD5 );
287  uno::Sequence< sal_Int8 > aUniqueID = aHashData.getUnpackedValueOrDefault("STD97UniqueID", uno::Sequence< sal_Int8 >() );
288  if ( aUniqueID.getLength() == 16 )
289  {
290  (void)memcpy( mpnUnique, aUniqueID.getConstArray(), 16 );
291  bResult = false;
292  }
293  else
294  OSL_FAIL( "Unexpected document ID!\n" );
295  }
296  else
297  OSL_FAIL( "Unexpected key size!\n" );
298 
299  return bResult;
300 }
301 
302 uno::Sequence< beans::NamedValue > BinaryCodec_RCF::getEncryptionData()
303 {
305  aHashData[ OUString("STD97EncryptionKey") ] <<= uno::Sequence< sal_Int8 >( (sal_Int8*)mpnDigestValue, RTL_DIGEST_LENGTH_MD5 );
306  aHashData[ OUString("STD97UniqueID") ] <<= uno::Sequence< sal_Int8 >( (sal_Int8*)mpnUnique, 16 );
307 
308  return aHashData.getAsConstNamedValueList();
309 }
310 
311 void BinaryCodec_RCF::initKey( const sal_uInt16 pnPassData[ 16 ], const sal_uInt8 pnSalt[ 16 ] )
312 {
313  uno::Sequence< sal_Int8 > aKey = ::comphelper::DocPasswordHelper::GenerateStd97Key( pnPassData, uno::Sequence< sal_Int8 >( (sal_Int8*)pnSalt, 16 ) );
314  // Fill raw digest of above updates into DigestValue.
315 
316  if ( aKey.getLength() == sizeof(mpnDigestValue) )
317  (void)memcpy ( mpnDigestValue, (const sal_uInt8*)aKey.getConstArray(), sizeof(mpnDigestValue) );
318  else
319  memset( mpnDigestValue, 0, sizeof(mpnDigestValue) );
320 
321  (void)memcpy( mpnUnique, pnSalt, 16 );
322 }
323 
324 bool BinaryCodec_RCF::verifyKey( const sal_uInt8 pnVerifier[ 16 ], const sal_uInt8 pnVerifierHash[ 16 ] )
325 {
326  if( !startBlock( 0 ) )
327  return false;
328 
329  sal_uInt8 pnDigest[ RTL_DIGEST_LENGTH_MD5 ];
330  sal_uInt8 pnBuffer[ 64 ];
331 
332  // decode salt data into buffer
333  rtl_cipher_decode( mhCipher, pnVerifier, 16, pnBuffer, sizeof( pnBuffer ) );
334 
335  pnBuffer[ 16 ] = 0x80;
336  (void)memset( pnBuffer + 17, 0, sizeof( pnBuffer ) - 17 );
337  pnBuffer[ 56 ] = 0x80;
338 
339  // fill raw digest of buffer into digest
340  rtl_digest_updateMD5( mhDigest, pnBuffer, sizeof( pnBuffer ) );
341  rtl_digest_rawMD5( mhDigest, pnDigest, sizeof( pnDigest ) );
342 
343  // decode original salt digest into buffer
344  rtl_cipher_decode( mhCipher, pnVerifierHash, 16, pnBuffer, sizeof( pnBuffer ) );
345 
346  // compare buffer with computed digest
347  bool bResult = memcmp( pnBuffer, pnDigest, sizeof( pnDigest ) ) == 0;
348 
349  // erase buffer and digest arrays and leave
350  (void)memset( pnBuffer, 0, sizeof( pnBuffer ) );
351  (void)memset( pnDigest, 0, sizeof( pnDigest ) );
352  return bResult;
353 }
354 
355 bool BinaryCodec_RCF::startBlock( sal_Int32 nCounter )
356 {
357  // initialize key data array
358  sal_uInt8 pnKeyData[ 64 ];
359  (void)memset( pnKeyData, 0, sizeof( pnKeyData ) );
360 
361  // fill 40 bit of digest value into [0..4]
362  (void)memcpy( pnKeyData, mpnDigestValue, 5 );
363 
364  // fill little-endian counter into [5..8], static_cast masks out unneeded bits
365  pnKeyData[ 5 ] = static_cast< sal_uInt8 >( nCounter );
366  pnKeyData[ 6 ] = static_cast< sal_uInt8 >( nCounter >> 8 );
367  pnKeyData[ 7 ] = static_cast< sal_uInt8 >( nCounter >> 16 );
368  pnKeyData[ 8 ] = static_cast< sal_uInt8 >( nCounter >> 24 );
369 
370  pnKeyData[ 9 ] = 0x80;
371  pnKeyData[ 56 ] = 0x48;
372 
373  // fill raw digest of key data into key data
374  (void)rtl_digest_updateMD5( mhDigest, pnKeyData, sizeof( pnKeyData ) );
375  (void)rtl_digest_rawMD5( mhDigest, pnKeyData, RTL_DIGEST_LENGTH_MD5 );
376 
377  // initialize cipher with key data (for decoding)
378  rtlCipherError eResult =
379  rtl_cipher_init( mhCipher, rtl_Cipher_DirectionDecode, pnKeyData, RTL_DIGEST_LENGTH_MD5, 0, 0 );
380 
381  // rrase key data array and leave
382  (void)memset( pnKeyData, 0, sizeof( pnKeyData ) );
383  return eResult == rtl_Cipher_E_None;
384 }
385 
386 bool BinaryCodec_RCF::decode( sal_uInt8* pnDestData, const sal_uInt8* pnSrcData, sal_Int32 nBytes )
387 {
388  rtlCipherError eResult = rtl_cipher_decode( mhCipher,
389  pnSrcData, static_cast< sal_Size >( nBytes ),
390  pnDestData, static_cast< sal_Size >( nBytes ) );
391  return eResult == rtl_Cipher_E_None;
392 }
393 
394 bool BinaryCodec_RCF::skip( sal_Int32 nBytes )
395 {
396  // decode dummy data in memory to update internal state of RC4 cipher
397  sal_uInt8 pnDummy[ 1024 ];
398  sal_Int32 nBytesLeft = nBytes;
399  bool bResult = true;
400  while( bResult && (nBytesLeft > 0) )
401  {
402  sal_Int32 nBlockLen = ::std::min( nBytesLeft, static_cast< sal_Int32 >( sizeof( pnDummy ) ) );
403  bResult = decode( pnDummy, pnDummy, nBlockLen );
404  nBytesLeft -= nBlockLen;
405  }
406  return bResult;
407 }
408 
409 } // namespace core
410 } // namespace oox
411 
412 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */