/**************************************************************************** * * sfwoff2.c * * WOFF2 format management (base). * * Copyright (C) 2019 by * Nikhil Ramakrishnan, David Turner, Robert Wilhelm, and Werner Lemberg. * * This file is part of the FreeType project, and may only be used, * modified, and distributed under the terms of the FreeType project * license, LICENSE.TXT. By continuing to use, modify, or distribute * this file you indicate that you have read the license and * understand and accept it fully. * */ #include #include "sfwoff2.h" #include "woff2tags.h" #include FT_TRUETYPE_TAGS_H #include FT_INTERNAL_DEBUG_H #include FT_INTERNAL_STREAM_H /************************************************************************** * * The macro FT_COMPONENT is used in trace mode. It is an implicit * parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log * messages during execution. */ #undef FT_COMPONENT #define FT_COMPONENT sfwoff2 #define READ_255USHORT( var ) Read255UShort( stream, &var ) #define READ_BASE128( var ) ReadBase128( stream, &var ) #define ROUND4( var ) ( var + 3 ) & ~3 static FT_Error Read255UShort( FT_Stream stream, FT_UShort* value ) { static const FT_Int oneMoreByteCode1 = 255; static const FT_Int oneMoreByteCode2 = 254; static const FT_Int wordCode = 253; static const FT_Int lowestUCode = 253; FT_Error error; FT_Byte code; FT_Byte result_byte = 0; FT_UShort result_short = 0; if( FT_READ_BYTE( code ) ) return FT_THROW( Invalid_Table ); if( code == wordCode ) { /* Read next two bytes and store UInt16 value */ if( FT_READ_USHORT( result_short ) ) return FT_THROW( Invalid_Table ); *value = result_short; return FT_Err_Ok; } else if( code == oneMoreByteCode1 ) { if( FT_READ_BYTE( result_byte ) ) return FT_THROW( Invalid_Table ); *value = result_byte + lowestUCode; return FT_Err_Ok; } else if( code == oneMoreByteCode2 ) { if( FT_READ_BYTE( result_byte ) ) return FT_THROW( Invalid_Table ); *value = result_byte + lowestUCode * 2; return FT_Err_Ok; } else { *value = code; return FT_Err_Ok; } } static FT_Error ReadBase128( FT_Stream stream, FT_ULong* value ) { FT_ULong result = 0; FT_Int i; FT_Byte code; FT_Error error; for ( i = 0; i < 5; ++i ) { code = 0; if( FT_READ_BYTE( code ) ) return FT_THROW( Invalid_Table ); /* Leading zeros are invalid. */ if ( i == 0 && code == 0x80 ) { return FT_THROW( Invalid_Table ); } /* If any of top seven bits are set then we're about to overflow. */ if ( result & 0xfe000000 ){ return FT_THROW( Invalid_Table ); } result = ( result << 7 ) | ( code & 0x7f ); /* Spin until most significant bit of data byte is false. */ if ( (code & 0x80) == 0 ) { *value = result; return FT_Err_Ok; } } /* Make sure not to exceed the size bound. */ return FT_THROW( Invalid_Table ); } static FT_Offset CollectionHeaderSize( FT_ULong header_version, FT_UShort num_fonts ) { FT_Offset size = 0; if (header_version == 0x00020000) size += 12; /* ulDsig{Tag,Length,Offset} */ if (header_version == 0x00010000 || header_version == 0x00020000) { size += 12 /* TTCTag, Version, numFonts */ + ( 4 * num_fonts ); /* OffsetTable[numFonts] */ } return size; } static FT_Error compute_first_table_offset( const WOFF2_Header woff2 ) { FT_Int nn; FT_Offset offset = WOFF2_SFNT_HEADER_SIZE + ( WOFF2_SFNT_ENTRY_SIZE * (FT_Offset)( woff2->num_tables ) ); if(woff2->header_version) { offset = CollectionHeaderSize( woff2->header_version, woff2->num_fonts ) + WOFF2_SFNT_HEADER_SIZE * woff2->num_fonts; for ( nn = 0; nn< woff2->num_fonts; nn++ ) { offset += WOFF2_SFNT_ENTRY_SIZE * woff2->ttc_fonts[nn].num_tables; } } return offset; } /* Replace `face->root.stream' with a stream containing the extracted */ /* SFNT of a WOFF2 font. */ FT_LOCAL_DEF( FT_Error ) woff2_open_font( FT_Stream stream, TT_Face face ) { FT_Memory memory = stream->memory; FT_Error error = FT_Err_Ok; WOFF2_HeaderRec woff2; WOFF2_Table tables = NULL; WOFF2_Table* indices = NULL; WOFF2_Table last_table; FT_Int nn; FT_ULong j; FT_ULong flags; FT_UShort xform_version; FT_ULong src_offset = 0; FT_UShort ttc_num_tables; FT_UInt glyf_index; FT_UInt loca_index; FT_UInt64 first_table_offset; FT_UInt64 file_offset; static const FT_Frame_Field woff2_header_fields[] = { #undef FT_STRUCTURE #define FT_STRUCTURE WOFF2_HeaderRec FT_FRAME_START( 48 ), FT_FRAME_ULONG ( signature ), FT_FRAME_ULONG ( flavor ), FT_FRAME_ULONG ( length ), FT_FRAME_USHORT( num_tables ), FT_FRAME_SKIP_BYTES( 2 + 4 ), FT_FRAME_ULONG ( totalCompressedSize ), FT_FRAME_SKIP_BYTES( 2 * 2 ), FT_FRAME_ULONG ( metaOffset ), FT_FRAME_ULONG ( metaLength ), FT_FRAME_ULONG ( metaOrigLength ), FT_FRAME_ULONG ( privOffset ), FT_FRAME_ULONG ( privLength ), FT_FRAME_END }; /* DEBUG - Remove later */ FT_TRACE2(( "woff2_open_font: Received Data.\n" )); FT_ASSERT( stream == face->root.stream ); FT_ASSERT( FT_STREAM_POS() == 0 ); /* Read WOFF2 Header. */ if ( FT_STREAM_READ_FIELDS( woff2_header_fields, &woff2 ) ) return error; /* DEBUG - Remove later. */ FT_TRACE2(( "signature -> 0x%X\n", woff2.signature )); FT_TRACE2(( "flavor -> 0x%X\n", woff2.flavor )); FT_TRACE2(( "length -> %lu\n", woff2.length )); FT_TRACE2(( "num_tables -> %hu\n", woff2.num_tables )); FT_TRACE2(( "metaOffset -> %hu\n", woff2.metaOffset )); FT_TRACE2(( "metaLength -> %hu\n", woff2.metaLength )); FT_TRACE2(( "privOffset -> %hu\n", woff2.privOffset )); FT_TRACE2(( "privLength -> %hu\n", woff2.privLength )); /* Make sure we don't recurse back here. */ if ( woff2.flavor == TTAG_wOF2 ) return FT_THROW( Invalid_Table ); /* Miscellaneous checks. */ if ( woff2.length != stream->size || woff2.num_tables == 0 || 48 + woff2.num_tables * 20UL >= woff2.length || ( woff2.metaOffset == 0 && ( woff2.metaLength != 0 || woff2.metaOrigLength != 0 ) ) || ( woff2.metaLength != 0 && woff2.metaOrigLength == 0 ) || ( woff2.metaOffset >= woff2.length ) || ( woff2.length - woff2.metaOffset < woff2.metaLength ) || ( woff2.privOffset == 0 && woff2.privLength != 0 ) || ( woff2.privOffset >= woff2.length ) || ( woff2.length - woff2.privOffset < woff2.privLength ) ) { FT_ERROR(( "woff2_font_open: invalid WOFF2 header\n" )); return FT_THROW( Invalid_Table ); } /* DEBUG - Remove later. */ else{ FT_TRACE2(( "WOFF2 Header is valid.\n" )); } /* Read table directory. */ if ( FT_NEW_ARRAY( tables, woff2.num_tables ) || FT_NEW_ARRAY( indices, woff2.num_tables ) ) goto Exit; FT_TRACE2(( "\n" " tag flags transform origLen transformLen\n" " --------------------------------------------------\n" )); /* TODO check whether there is sufficient input before FT_READ_*. */ for ( nn = 0; nn < woff2.num_tables; nn++ ) { WOFF2_Table table = tables + nn; if( FT_READ_BYTE( table->FlagByte ) ) goto Exit; if ( ( table->FlagByte & 0x3f ) == 0x3f ) { if( FT_READ_ULONG( table->Tag ) ) goto Exit; } else table->Tag = KnownTags[table->FlagByte & 0x3f]; flags = 0; xform_version = ( table->FlagByte >> 6 ) & 0x03; /* 0 means xform for glyph/loca, non-0 for others. */ if ( table->Tag == TTAG_glyf || table->Tag == TTAG_loca ) { if ( xform_version == 0 ) flags |= WOFF2_FLAGS_TRANSFORM; } else if ( xform_version != 0 ) flags |= WOFF2_FLAGS_TRANSFORM; flags |= xform_version; if( READ_BASE128( table->OrigLength ) ) goto Exit; table->TransformLength = table->OrigLength; if ( ( flags & WOFF2_FLAGS_TRANSFORM ) != 0 ) { if( READ_BASE128( table->TransformLength ) ) goto Exit; if( table->Tag == TTAG_loca && table->TransformLength ) { FT_ERROR(( "woff_font_open: Invalid loca `transformLength'.\n" )); return FT_THROW( Invalid_Table ); } } if ( src_offset + table->TransformLength < src_offset ) { FT_ERROR(( "woff_font_open: invalid WOFF2 table directory.\n" )); return FT_THROW( Invalid_Table ); } table->src_offset = src_offset; table->src_length = table->TransformLength; src_offset += table->TransformLength; table->flags = flags; FT_TRACE2(( " %c%c%c%c %08d %08d %08ld %08ld\n", (FT_Char)( table->Tag >> 24 ), (FT_Char)( table->Tag >> 16 ), (FT_Char)( table->Tag >> 8 ), (FT_Char)( table->Tag ), table->FlagByte & 0x3f, ( table->FlagByte >> 6 ) & 0x03, table->OrigLength, table->TransformLength, table->src_length, table->src_offset )); indices[nn] = table; } /* End of last table is uncompressed size. */ last_table = indices[woff2.num_tables - 1]; woff2.uncompressed_size = last_table->src_offset + last_table->src_length; if( woff2.uncompressed_size < last_table->src_offset ) return FT_THROW( Invalid_Table ); /* DEBUG - Remove later. */ FT_TRACE2(( "Uncompressed size: %ld\n", woff2.uncompressed_size )); FT_TRACE2(( "Table directory successfully parsed.\n" )); /* Check for and read collection directory. */ woff2.header_version = 0; if( woff2.flavor == TTAG_ttcf ){ FT_TRACE2(( "Font is a TTC, reading collection directory.\n" )); if( FT_READ_ULONG( woff2.header_version ) ) goto Exit; /* DEBUG - Remove later */ FT_TRACE2(( "Header version: %lx\n", woff2.header_version )); if( woff2.header_version != 0x00010000 && woff2.header_version != 0x00020000 ) return FT_THROW( Invalid_Table ); if( READ_255USHORT( woff2.num_fonts ) ) goto Exit; /* DEBUG - Remove later */ FT_TRACE2(( "Number of fonts in TTC: %ld\n", woff2.num_fonts )); if( FT_NEW_ARRAY( woff2.ttc_fonts, woff2.num_fonts ) ) goto Exit; for ( nn = 0; nn < woff2.num_fonts; nn++ ) { WOFF2_TtcFont ttc_font = woff2.ttc_fonts + nn; if( READ_255USHORT( ttc_num_tables ) ) goto Exit; if( FT_READ_ULONG( ttc_font->flavor ) ) goto Exit; if( FT_NEW_ARRAY( ttc_font->table_indices, ttc_num_tables ) ) goto Exit; /* DEBUG - Change to TRACE4 */ FT_TRACE2(( "Number of tables in font %d: %ld\n", nn, ttc_num_tables )); /* DEBUG - Change to TRACE5 */ FT_TRACE2(( " Indices: " )); glyf_index = 0; loca_index = 0; for ( j = 0; j < ttc_num_tables; j++ ) { FT_UShort table_index; WOFF2_Table table; if( READ_255USHORT( table_index ) ) goto Exit; /* DEBUG - Change to TRACE5 */ FT_TRACE2(("%hu ", table_index)); ttc_font->table_indices[j] = table_index; table = indices[table_index]; if( table->Tag == TTAG_loca ) loca_index = table_index; if( table->Tag == TTAG_glyf ) glyf_index = table_index; } /* DEBUG - Change to TRACE5 */ FT_TRACE2(( "\n" )); /* glyf and loca must be consecutive */ if( glyf_index > 0 || loca_index > 0 ) { if(glyf_index > loca_index || loca_index - glyf_index != 1) return FT_THROW( Invalid_Table ); /* DEBUG - Remove later */ else FT_TRACE2(( "Glyf and loca are valid.\n" )); } } /* Collection directory reading complete. */ FT_TRACE2(( "WOFF2 collection dirtectory is valid.\n" )); } first_table_offset = compute_first_table_offset( &woff2 ); FT_TRACE2(( "Offset to first table: %ld\n", first_table_offset )); woff2.compressed_offset = FT_STREAM_POS(); file_offset = ROUND4( woff2.compressed_offset + woff2.totalCompressedSize ); /* Few more checks before we start reading the tables */ if( file_offset > woff2.length ) return FT_THROW( Invalid_Table ); if ( woff2.metaOffset ) { if ( file_offset != woff2.metaOffset ) return FT_THROW( Invalid_Table ); file_offset = ROUND4(woff2.metaOffset + woff2.metaLength); } if( woff2.privOffset ) { if( file_offset != woff2.privOffset ) return FT_THROW( Invalid_Table ); file_offset = ROUND4(woff2.privOffset + woff2.privLength); } if( file_offset != ( ROUND4( woff2.length ) ) ) return FT_THROW( Invalid_Table ); error = FT_THROW( Unimplemented_Feature ); FT_TRACE2(( "Reached end without errors.\n" )); goto Exit; Exit: return error; } #undef READ_255USHORT #undef READ_BASE128 #undef ROUND4 /* END */