File indexing completed on 2024-04-28 11:38:33

 /*
     This file is part of the KDE libraries
 
     The Original Code is WOFF font packaging code.
     Copyright (C) 2009 Mozilla Corporation
 
     Contributor(s):
       Jonathan Kew <jfkthame@gmail.com>
       Germain Garand <germain@ebooksfrance.org>
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
     version 2 of the License, or (at your option) any later version.
 
     This library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Library General Public License for more details.
 
     You should have received a copy of the GNU Library General Public License
     along with this library; see the file COPYING.LIB.  If not, write to
     the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA 02110-1301, USA.
 */
 
 #include "woff-private.h"
 #include <string.h>
 #include <stdlib.h>
 #include <zlib.h>
 
 using namespace WOFF;
 
 /* on errors, each function sets a status variable and jumps to failure: */
 #undef FAIL
 #define FAIL(err) do { status |= err; goto failure; } while (0)
 
 /* adjust an offset for longword alignment */
 #define LONGALIGN(x) (((x) + 3) & ~3)
 
 static int compareOffsets(const void *lhs, const void *rhs)
 {
     const tableOrderRec *a = (const tableOrderRec *) lhs;
     const tableOrderRec *b = (const tableOrderRec *) rhs;
     /* don't simply return a->offset - b->offset because these are unsigned
        offset values; could convert to int, but possible integer overflow */
     return a->offset > b->offset ? 1 :
            a->offset < b->offset ? -1 :
            0;
 }
 
 static int sanityCheck(const char *woffData, int _woffLen)
 {
     quint32 woffLen = _woffLen;
     const woffHeader *header;
     quint16 numTables, i;
     const woffDirEntry *dirEntry;
     quint32 tableTotal = 0;
 
     if (!woffData || !woffLen) {
         return eWOFF_bad_parameter;
     }
 
     if (woffLen < sizeof(woffHeader)) {
         return eWOFF_invalid;
     }
 
     header = (const woffHeader *)(woffData);
     if (READ32BE(header->signature) != WOFF_SIGNATURE) {
         return eWOFF_bad_signature;
     }
 
     if (READ32BE(header->length) != woffLen || header->reserved != 0) {
         return eWOFF_invalid;
     }
 
     numTables = READ16BE(header->numTables);
     if (woffLen < sizeof(woffHeader) + numTables * sizeof(woffDirEntry)) {
         return eWOFF_invalid;
     }
 
     dirEntry = (const woffDirEntry *)(woffData + sizeof(woffHeader));
     for (i = 0; i < numTables; ++i) {
         quint32 offs = READ32BE(dirEntry->offset);
         quint32 orig = READ32BE(dirEntry->origLen);
         quint32 comp = READ32BE(dirEntry->compLen);
         if (comp > orig || comp > woffLen || offs > woffLen - comp) {
             return eWOFF_invalid;
         }
         orig = (orig + 3) & ~3;
         if (tableTotal > 0xffffffffU - orig) {
             return eWOFF_invalid;
         }
         tableTotal += orig;
         ++dirEntry;
     }
 
     if (tableTotal > 0xffffffffU - sizeof(sfntHeader) -
             numTables * sizeof(sfntDirEntry) ||
             READ32BE(header->totalSfntSize) !=
             tableTotal + sizeof(sfntHeader) + numTables * sizeof(sfntDirEntry)) {
         return eWOFF_invalid;
     }
 
     return eWOFF_ok;
 }
 
 int WOFF::getDecodedSize(const char *woffData, int woffLen, int *pStatus)
 {
     int status = eWOFF_ok;
     quint32 totalLen = 0;
 
     if (pStatus && WOFF_FAILURE(*pStatus)) {
         return 0;
     }
 
     status = sanityCheck(woffData, woffLen);
     if (WOFF_FAILURE(status)) {
         FAIL(status);
     }
 
     totalLen = READ32BE(((const woffHeader *)(woffData))->totalSfntSize);
     /* totalLen must be correctly rounded up to 4-byte alignment, otherwise
        sanityCheck would have failed */
 
 failure:
     if (pStatus) {
         *pStatus = status;
     }
     return totalLen;
 }
 
 static void woffDecodeToBufferInternal(const char *woffData, char *sfntData, int *pActualSfntLen, int *pStatus)
 {
     /* this is only called after sanityCheck has verified that
        (a) basic header fields are ok
        (b) all the WOFF table offset/length pairs are valid (within the data)
        (c) the sum of original sizes + header/directory matches totalSfntSize
        so we don't have to re-check those overflow conditions here */
     tableOrderRec *tableOrder = nullptr;
     const woffHeader *header;
     quint16 numTables;
     quint16 tableIndex;
     quint16 order;
     const woffDirEntry *woffDir;
     quint32 totalLen;
     sfntHeader *newHeader;
     quint16 searchRange, rangeShift, entrySelector;
     quint32 offset;
     sfntDirEntry *sfntDir;
     quint32 headOffset = 0, headLength = 0;
     sfntHeadTable *head;
     quint32 csum = 0;
     const quint32 *csumPtr;
     quint32 oldCheckSumAdjustment;
     quint32 status = eWOFF_ok;
 
     if (pStatus && WOFF_FAILURE(*pStatus)) {
         return;
     }
 
     /* check basic header fields */
     header = (const woffHeader *)(woffData);
     if (READ32BE(header->flavor) != SFNT_VERSION_TT &&
             READ32BE(header->flavor) != SFNT_VERSION_CFF &&
             READ32BE(header->flavor) != SFNT_VERSION_true) {
         status |= eWOFF_warn_unknown_version;
     }
 
     numTables = READ16BE(header->numTables);
     woffDir = (const woffDirEntry *)(woffData + sizeof(woffHeader));
 
     totalLen = READ32BE(header->totalSfntSize);
 
     /* construct the sfnt header */
     newHeader = (sfntHeader *)(sfntData);
     newHeader->version = header->flavor;
     newHeader->numTables = READ16BE(numTables);
 
     /* calculate header fields for binary search */
     searchRange = numTables;
     searchRange |= (searchRange >> 1);
     searchRange |= (searchRange >> 2);
     searchRange |= (searchRange >> 4);
     searchRange |= (searchRange >> 8);
     searchRange &= ~(searchRange >> 1);
     searchRange *= 16;
     newHeader->searchRange = READ16BE(searchRange);
     rangeShift = numTables * 16 - searchRange;
     newHeader->rangeShift = READ16BE(rangeShift);
     entrySelector = 0;
     while (searchRange > 16) {
         ++entrySelector;
         searchRange >>= 1;
     }
     newHeader->entrySelector = READ16BE(entrySelector);
 
     tableOrder = (tableOrderRec *) malloc(numTables * sizeof(tableOrderRec));
     if (!tableOrder) {
         FAIL(eWOFF_out_of_memory);
     }
     for (tableIndex = 0; tableIndex < numTables; ++tableIndex) {
         tableOrder[tableIndex].offset = READ32BE(woffDir[tableIndex].offset);
         tableOrder[tableIndex].oldIndex = tableIndex;
     }
     qsort(tableOrder, numTables, sizeof(tableOrderRec), compareOffsets);
 
     /* process each table, filling in the sfnt directory */
     offset = sizeof(sfntHeader) + numTables * sizeof(sfntDirEntry);
     sfntDir = (sfntDirEntry *)(sfntData + sizeof(sfntHeader));
     for (order = 0; order < numTables; ++order) {
         quint32 origLen, compLen, tag, sourceOffset;
         tableIndex = tableOrder[order].oldIndex;
 
         /* validity of these was confirmed by sanityCheck */
         origLen = READ32BE(woffDir[tableIndex].origLen);
         compLen = READ32BE(woffDir[tableIndex].compLen);
         sourceOffset = READ32BE(woffDir[tableIndex].offset);
 
         sfntDir[tableIndex].tag = woffDir[tableIndex].tag;
         sfntDir[tableIndex].offset = READ32BE(offset);
         sfntDir[tableIndex].length = woffDir[tableIndex].origLen;
         sfntDir[tableIndex].checksum = woffDir[tableIndex].checksum;
         csum += READ32BE(sfntDir[tableIndex].checksum);
 
         if (compLen < origLen) {
             uLongf destLen = origLen;
             if (uncompress((Bytef *)(sfntData + offset), &destLen,
                            (const Bytef *)(woffData + sourceOffset),
                            compLen) != Z_OK || destLen != origLen) {
                 FAIL(eWOFF_compression_failure);
             }
         } else {
             memcpy(sfntData + offset, woffData + sourceOffset, origLen);
         }
 
         /* note that old Mac bitmap-only fonts have no 'head' table
            (eg NISC18030.ttf) but a 'bhed' table instead */
         tag = READ32BE(sfntDir[tableIndex].tag);
         if (tag == TABLE_TAG_head || tag == TABLE_TAG_bhed) {
             headOffset = offset;
             headLength = origLen;
         }
 
         offset += origLen;
 
         while (offset < totalLen && (offset & 3) != 0) {
             sfntData[offset++] = 0;
         }
     }
 
     if (headOffset > 0) {
         /* the font checksum in the 'head' table depends on all the individual
            table checksums (collected above), plus the header and directory
            which are added in here */
         if (headLength < HEAD_TABLE_SIZE) {
             FAIL(eWOFF_invalid);
         }
         head = (sfntHeadTable *)(sfntData + headOffset);
         oldCheckSumAdjustment = READ32BE(head->checkSumAdjustment);
         head->checkSumAdjustment = 0;
         csumPtr = (const quint32 *)sfntData;
         while (csumPtr < (const quint32 *)(sfntData + sizeof(sfntHeader) +
                                            numTables * sizeof(sfntDirEntry))) {
             csum += READ32BE(*csumPtr);
             csumPtr++;
         }
         csum = SFNT_CHECKSUM_CALC_CONST - csum;
 
         if (oldCheckSumAdjustment != csum) {
             /* if the checksum doesn't match, we fix it; but this will invalidate
                any DSIG that may be present */
             status |= eWOFF_warn_checksum_mismatch;
         }
         head->checkSumAdjustment = READ32BE(csum);
     }
 
     if (pActualSfntLen) {
         *pActualSfntLen = totalLen;
     }
     if (pStatus) {
         *pStatus |= status;
     }
     free(tableOrder);
     return;
 
 failure:
     if (tableOrder) {
         free(tableOrder);
     }
     if (pActualSfntLen) {
         *pActualSfntLen = 0;
     }
     if (pStatus) {
         *pStatus = status;
     }
 }
 
 void WOFF::decodeToBuffer(const char *woffData, int woffLen, char *sfntData, int bufferLen,
                           int *pActualSfntLen, int *pStatus)
 {
     quint32 status = eWOFF_ok;
     quint32 totalLen;
 
     if (pStatus && WOFF_FAILURE(*pStatus)) {
         return;
     }
 
     status = sanityCheck(woffData, woffLen);
     if (WOFF_FAILURE(status)) {
         FAIL(status);
     }
 
     if (!sfntData) {
         FAIL(eWOFF_bad_parameter);
     }
 
     totalLen = READ32BE(((const woffHeader *)(woffData))->totalSfntSize);
     if ((unsigned)bufferLen < totalLen) {
         FAIL(eWOFF_buffer_too_small);
     }
 
     woffDecodeToBufferInternal(woffData, sfntData, pActualSfntLen, pStatus);
     return;
 
 failure:
     if (pActualSfntLen) {
         *pActualSfntLen = 0;
     }
     if (pStatus) {
         *pStatus = status;
     }
 }