1 /**************************************************************************** 2 * 3 * sfwoff.c 4 * 5 * WOFF format management (base). 6 * 7 * Copyright (C) 1996-2023 by 8 * David Turner, Robert Wilhelm, and Werner Lemberg. 9 * 10 * This file is part of the FreeType project, and may only be used, 11 * modified, and distributed under the terms of the FreeType project 12 * license, LICENSE.TXT. By continuing to use, modify, or distribute 13 * this file you indicate that you have read the license and 14 * understand and accept it fully. 15 * 16 */ 17 18 19 #include "sfwoff.h" 20 #include <freetype/tttags.h> 21 #include <freetype/internal/ftdebug.h> 22 #include <freetype/internal/ftstream.h> 23 #include <freetype/ftgzip.h> 24 25 26 #ifdef FT_CONFIG_OPTION_USE_ZLIB 27 28 29 /************************************************************************** 30 * 31 * The macro FT_COMPONENT is used in trace mode. It is an implicit 32 * parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log 33 * messages during execution. 34 */ 35 #undef FT_COMPONENT 36 #define FT_COMPONENT sfwoff 37 38 39 #define WRITE_USHORT( p, v ) \ 40 do \ 41 { \ 42 *(p)++ = (FT_Byte)( (v) >> 8 ); \ 43 *(p)++ = (FT_Byte)( (v) >> 0 ); \ 44 \ 45 } while ( 0 ) 46 47 #define WRITE_ULONG( p, v ) \ 48 do \ 49 { \ 50 *(p)++ = (FT_Byte)( (v) >> 24 ); \ 51 *(p)++ = (FT_Byte)( (v) >> 16 ); \ 52 *(p)++ = (FT_Byte)( (v) >> 8 ); \ 53 *(p)++ = (FT_Byte)( (v) >> 0 ); \ 54 \ 55 } while ( 0 ) 56 57 58 static void sfnt_stream_close(FT_Stream stream)59 sfnt_stream_close( FT_Stream stream ) 60 { 61 FT_Memory memory = stream->memory; 62 63 64 FT_FREE( stream->base ); 65 66 stream->size = 0; 67 stream->close = NULL; 68 } 69 70 71 FT_COMPARE_DEF( int ) compare_offsets(const void * a,const void * b)72 compare_offsets( const void* a, 73 const void* b ) 74 { 75 WOFF_Table table1 = *(WOFF_Table*)a; 76 WOFF_Table table2 = *(WOFF_Table*)b; 77 78 FT_ULong offset1 = table1->Offset; 79 FT_ULong offset2 = table2->Offset; 80 81 82 if ( offset1 > offset2 ) 83 return 1; 84 else if ( offset1 < offset2 ) 85 return -1; 86 else 87 return 0; 88 } 89 90 91 /* Replace `face->root.stream' with a stream containing the extracted */ 92 /* SFNT of a WOFF font. */ 93 94 FT_LOCAL_DEF( FT_Error ) woff_open_font(FT_Stream stream,TT_Face face)95 woff_open_font( FT_Stream stream, 96 TT_Face face ) 97 { 98 FT_Memory memory = stream->memory; 99 FT_Error error = FT_Err_Ok; 100 101 WOFF_HeaderRec woff; 102 WOFF_Table tables = NULL; 103 WOFF_Table* indices = NULL; 104 105 FT_ULong woff_offset; 106 107 FT_Byte* sfnt = NULL; 108 FT_Stream sfnt_stream = NULL; 109 110 FT_Byte* sfnt_header; 111 FT_ULong sfnt_offset; 112 113 FT_Int nn; 114 FT_Tag old_tag = 0; 115 116 static const FT_Frame_Field woff_header_fields[] = 117 { 118 #undef FT_STRUCTURE 119 #define FT_STRUCTURE WOFF_HeaderRec 120 121 FT_FRAME_START( 44 ), 122 FT_FRAME_ULONG ( signature ), 123 FT_FRAME_ULONG ( flavor ), 124 FT_FRAME_ULONG ( length ), 125 FT_FRAME_USHORT( num_tables ), 126 FT_FRAME_USHORT( reserved ), 127 FT_FRAME_ULONG ( totalSfntSize ), 128 FT_FRAME_USHORT( majorVersion ), 129 FT_FRAME_USHORT( minorVersion ), 130 FT_FRAME_ULONG ( metaOffset ), 131 FT_FRAME_ULONG ( metaLength ), 132 FT_FRAME_ULONG ( metaOrigLength ), 133 FT_FRAME_ULONG ( privOffset ), 134 FT_FRAME_ULONG ( privLength ), 135 FT_FRAME_END 136 }; 137 138 139 FT_ASSERT( stream == face->root.stream ); 140 FT_ASSERT( FT_STREAM_POS() == 0 ); 141 142 if ( FT_STREAM_READ_FIELDS( woff_header_fields, &woff ) ) 143 return error; 144 145 /* Make sure we don't recurse back here or hit TTC code. */ 146 if ( woff.flavor == TTAG_wOFF || woff.flavor == TTAG_ttcf ) 147 return FT_THROW( Invalid_Table ); 148 149 /* Miscellaneous checks. */ 150 if ( woff.length != stream->size || 151 woff.num_tables == 0 || 152 44 + woff.num_tables * 20UL >= woff.length || 153 12 + woff.num_tables * 16UL >= woff.totalSfntSize || 154 ( woff.totalSfntSize & 3 ) != 0 || 155 ( woff.metaOffset == 0 && ( woff.metaLength != 0 || 156 woff.metaOrigLength != 0 ) ) || 157 ( woff.metaLength != 0 && woff.metaOrigLength == 0 ) || 158 ( woff.privOffset == 0 && woff.privLength != 0 ) ) 159 { 160 FT_ERROR(( "woff_font_open: invalid WOFF header\n" )); 161 return FT_THROW( Invalid_Table ); 162 } 163 164 /* Don't trust `totalSfntSize' before thorough checks. */ 165 if ( FT_QALLOC( sfnt, 12 ) || FT_NEW( sfnt_stream ) ) 166 goto Exit; 167 168 sfnt_header = sfnt; 169 170 /* Write sfnt header. */ 171 { 172 FT_UInt searchRange, entrySelector, rangeShift, x; 173 174 175 x = woff.num_tables; 176 entrySelector = 0; 177 while ( x ) 178 { 179 x >>= 1; 180 entrySelector += 1; 181 } 182 entrySelector--; 183 184 searchRange = ( 1 << entrySelector ) * 16; 185 rangeShift = woff.num_tables * 16 - searchRange; 186 187 WRITE_ULONG ( sfnt_header, woff.flavor ); 188 WRITE_USHORT( sfnt_header, woff.num_tables ); 189 WRITE_USHORT( sfnt_header, searchRange ); 190 WRITE_USHORT( sfnt_header, entrySelector ); 191 WRITE_USHORT( sfnt_header, rangeShift ); 192 } 193 194 /* While the entries in the sfnt header must be sorted by the */ 195 /* tag value, the tables themselves are not. We thus have to */ 196 /* sort them by offset and check that they don't overlap. */ 197 198 if ( FT_QNEW_ARRAY( tables, woff.num_tables ) || 199 FT_QNEW_ARRAY( indices, woff.num_tables ) ) 200 goto Exit; 201 202 FT_TRACE2(( "\n" )); 203 FT_TRACE2(( " tag offset compLen origLen checksum\n" )); 204 FT_TRACE2(( " -------------------------------------------\n" )); 205 206 if ( FT_FRAME_ENTER( 20L * woff.num_tables ) ) 207 goto Exit; 208 209 for ( nn = 0; nn < woff.num_tables; nn++ ) 210 { 211 WOFF_Table table = tables + nn; 212 213 table->Tag = FT_GET_TAG4(); 214 table->Offset = FT_GET_ULONG(); 215 table->CompLength = FT_GET_ULONG(); 216 table->OrigLength = FT_GET_ULONG(); 217 table->CheckSum = FT_GET_ULONG(); 218 219 FT_TRACE2(( " %c%c%c%c %08lx %08lx %08lx %08lx\n", 220 (FT_Char)( table->Tag >> 24 ), 221 (FT_Char)( table->Tag >> 16 ), 222 (FT_Char)( table->Tag >> 8 ), 223 (FT_Char)( table->Tag ), 224 table->Offset, 225 table->CompLength, 226 table->OrigLength, 227 table->CheckSum )); 228 229 if ( table->Tag <= old_tag ) 230 { 231 FT_FRAME_EXIT(); 232 233 FT_ERROR(( "woff_font_open: table tags are not sorted\n" )); 234 error = FT_THROW( Invalid_Table ); 235 goto Exit; 236 } 237 238 old_tag = table->Tag; 239 indices[nn] = table; 240 } 241 242 FT_FRAME_EXIT(); 243 244 /* Sort by offset. */ 245 246 ft_qsort( indices, 247 woff.num_tables, 248 sizeof ( WOFF_Table ), 249 compare_offsets ); 250 251 /* Check offsets and lengths. */ 252 253 woff_offset = 44 + woff.num_tables * 20L; 254 sfnt_offset = 12 + woff.num_tables * 16L; 255 256 for ( nn = 0; nn < woff.num_tables; nn++ ) 257 { 258 WOFF_Table table = indices[nn]; 259 260 261 if ( table->Offset != woff_offset || 262 table->CompLength > woff.length || 263 table->Offset > woff.length - table->CompLength || 264 table->OrigLength > woff.totalSfntSize || 265 sfnt_offset > woff.totalSfntSize - table->OrigLength || 266 table->CompLength > table->OrigLength ) 267 { 268 FT_ERROR(( "woff_font_open: invalid table offsets\n" )); 269 error = FT_THROW( Invalid_Table ); 270 goto Exit; 271 } 272 273 table->OrigOffset = sfnt_offset; 274 275 /* The offsets must be multiples of 4. */ 276 woff_offset += ( table->CompLength + 3 ) & ~3U; 277 sfnt_offset += ( table->OrigLength + 3 ) & ~3U; 278 } 279 280 /* 281 * Final checks! 282 * 283 * We don't decode and check the metadata block. 284 * We don't check table checksums either. 285 * But other than those, I think we implement all 286 * `MUST' checks from the spec. 287 */ 288 289 if ( woff.metaOffset ) 290 { 291 if ( woff.metaOffset != woff_offset || 292 woff.metaOffset + woff.metaLength > woff.length ) 293 { 294 FT_ERROR(( "woff_font_open:" 295 " invalid `metadata' offset or length\n" )); 296 error = FT_THROW( Invalid_Table ); 297 goto Exit; 298 } 299 300 /* We have padding only ... */ 301 woff_offset += woff.metaLength; 302 } 303 304 if ( woff.privOffset ) 305 { 306 /* ... if it isn't the last block. */ 307 woff_offset = ( woff_offset + 3 ) & ~3U; 308 309 if ( woff.privOffset != woff_offset || 310 woff.privOffset + woff.privLength > woff.length ) 311 { 312 FT_ERROR(( "woff_font_open: invalid `private' offset or length\n" )); 313 error = FT_THROW( Invalid_Table ); 314 goto Exit; 315 } 316 317 /* No padding for the last block. */ 318 woff_offset += woff.privLength; 319 } 320 321 if ( sfnt_offset != woff.totalSfntSize || 322 woff_offset != woff.length ) 323 { 324 FT_ERROR(( "woff_font_open: invalid `sfnt' table structure\n" )); 325 error = FT_THROW( Invalid_Table ); 326 goto Exit; 327 } 328 329 /* Now use `totalSfntSize'. */ 330 if ( FT_QREALLOC( sfnt, 12, woff.totalSfntSize ) ) 331 goto Exit; 332 333 sfnt_header = sfnt + 12; 334 335 /* Write the tables. */ 336 337 for ( nn = 0; nn < woff.num_tables; nn++ ) 338 { 339 WOFF_Table table = tables + nn; 340 341 342 /* Write SFNT table entry. */ 343 WRITE_ULONG( sfnt_header, table->Tag ); 344 WRITE_ULONG( sfnt_header, table->CheckSum ); 345 WRITE_ULONG( sfnt_header, table->OrigOffset ); 346 WRITE_ULONG( sfnt_header, table->OrigLength ); 347 348 /* Write table data. */ 349 if ( FT_STREAM_SEEK( table->Offset ) || 350 FT_FRAME_ENTER( table->CompLength ) ) 351 goto Exit; 352 353 if ( table->CompLength == table->OrigLength ) 354 { 355 /* Uncompressed data; just copy. */ 356 ft_memcpy( sfnt + table->OrigOffset, 357 stream->cursor, 358 table->OrigLength ); 359 } 360 else 361 { 362 /* Uncompress with zlib. */ 363 FT_ULong output_len = table->OrigLength; 364 365 366 error = FT_Gzip_Uncompress( memory, 367 sfnt + table->OrigOffset, &output_len, 368 stream->cursor, table->CompLength ); 369 if ( error ) 370 goto Exit1; 371 if ( output_len != table->OrigLength ) 372 { 373 FT_ERROR(( "woff_font_open: compressed table length mismatch\n" )); 374 error = FT_THROW( Invalid_Table ); 375 goto Exit1; 376 } 377 } 378 379 FT_FRAME_EXIT(); 380 381 /* We don't check whether the padding bytes in the WOFF file are */ 382 /* actually '\0'. For the output, however, we do set them properly. */ 383 sfnt_offset = table->OrigOffset + table->OrigLength; 384 while ( sfnt_offset & 3 ) 385 { 386 sfnt[sfnt_offset] = '\0'; 387 sfnt_offset++; 388 } 389 } 390 391 /* Ok! Finally ready. Swap out stream and return. */ 392 FT_Stream_OpenMemory( sfnt_stream, sfnt, woff.totalSfntSize ); 393 sfnt_stream->memory = stream->memory; 394 sfnt_stream->close = sfnt_stream_close; 395 396 FT_Stream_Free( 397 face->root.stream, 398 ( face->root.face_flags & FT_FACE_FLAG_EXTERNAL_STREAM ) != 0 ); 399 400 face->root.stream = sfnt_stream; 401 402 face->root.face_flags &= ~FT_FACE_FLAG_EXTERNAL_STREAM; 403 404 Exit: 405 FT_FREE( tables ); 406 FT_FREE( indices ); 407 408 if ( error ) 409 { 410 FT_FREE( sfnt ); 411 FT_Stream_Close( sfnt_stream ); 412 FT_FREE( sfnt_stream ); 413 } 414 415 return error; 416 417 Exit1: 418 FT_FRAME_EXIT(); 419 goto Exit; 420 } 421 422 423 #undef WRITE_USHORT 424 #undef WRITE_ULONG 425 426 #else /* !FT_CONFIG_OPTION_USE_ZLIB */ 427 428 /* ANSI C doesn't like empty source files */ 429 typedef int sfwoff_dummy_; 430 431 #endif /* !FT_CONFIG_OPTION_USE_ZLIB */ 432 433 434 /* END */ 435