Commit message: * libtiff/tif_read.c, libtiff/tiffiop.h: fix uint32 overflow in
TIFFReadEncodedStrip() that caused an integer division by zero.
Reported by Agostino Sarubbo.
Fixes http://bugzilla.maptools.org/show_bug.cgi?id=2596
CVE: CVE-2016-10266
CWE: CWE-369
Vulnerability description: LibTIFF 4.0.7 allows remote attackers to cause a denial of service (divide-by-zero error and application crash) via a crafted TIFF image, related to libtiff/tif_read.c:351:22.

Project: libtiff

TIFFFillStrip(TIFF* tif, uint32 strip)
{
	static const char module[] = "TIFFFillStrip";
	TIFFDirectory *td = &tif->tif_dir;

        if (!_TIFFFillStriles( tif ) || !tif->tif_dir.td_stripbytecount)
            return 0;

	if ((tif->tif_flags&TIFF_NOREADRAW)==0)
	{
		uint64 bytecount = td->td_stripbytecount[strip];
		if ((int64)bytecount <= 0) {
#if defined(__WIN32__) && (defined(_MSC_VER) || defined(__MINGW32__))
			TIFFErrorExt(tif->tif_clientdata, module,
				"Invalid strip byte count %I64u, strip %lu",
				     (unsigned __int64) bytecount,
				     (unsigned long) strip);
#else
			TIFFErrorExt(tif->tif_clientdata, module,
				"Invalid strip byte count %llu, strip %lu",
				     (unsigned long long) bytecount,
				     (unsigned long) strip);
#endif
			return (0);
		}
		if (isMapped(tif) &&
		    (isFillOrder(tif, td->td_fillorder)
		    || (tif->tif_flags & TIFF_NOBITREV))) {
			/*
			 * The image is mapped into memory and we either don't
			 * need to flip bits or the compression routine is
			 * going to handle this operation itself.  In this
			 * case, avoid copying the raw data and instead just
			 * reference the data from the memory mapped file
			 * image.  This assumes that the decompression
			 * routines do not modify the contents of the raw data
			 * buffer (if they try to, the application will get a
			 * fault since the file is mapped read-only).
			 */
			if ((tif->tif_flags & TIFF_MYBUFFER) && tif->tif_rawdata) {
				_TIFFfree(tif->tif_rawdata);
				tif->tif_rawdata = NULL;
				tif->tif_rawdatasize = 0;
			}
			tif->tif_flags &= ~TIFF_MYBUFFER;
			/*
			 * We must check for overflow, potentially causing
			 * an OOB read. Instead of simple
			 *
			 *  td->td_stripoffset[strip]+bytecount > tif->tif_size
			 *
			 * comparison (which can overflow) we do the following
			 * two comparisons:
			 */
			if (bytecount > (uint64)tif->tif_size ||
			    td->td_stripoffset[strip] > (uint64)tif->tif_size - bytecount) {
				/*
				 * This error message might seem strange, but
				 * it's what would happen if a read were done
				 * instead.
				 */
#if defined(__WIN32__) && (defined(_MSC_VER) || defined(__MINGW32__))
				TIFFErrorExt(tif->tif_clientdata, module,

					"Read error on strip %lu; "
					"got %I64u bytes, expected %I64u",
					(unsigned long) strip,
					(unsigned __int64) tif->tif_size - td->td_stripoffset[strip],
					(unsigned __int64) bytecount);
#else
				TIFFErrorExt(tif->tif_clientdata, module,

					"Read error on strip %lu; "
					"got %llu bytes, expected %llu",
					(unsigned long) strip,
					(unsigned long long) tif->tif_size - td->td_stripoffset[strip],
					(unsigned long long) bytecount);
#endif
				tif->tif_curstrip = NOSTRIP;
				return (0);
			}
			tif->tif_rawdatasize = (tmsize_t)bytecount;
			tif->tif_rawdata = tif->tif_base + (tmsize_t)td->td_stripoffset[strip];
                        tif->tif_rawdataoff = 0;
                        tif->tif_rawdataloaded = (tmsize_t) bytecount;

			/* 
			 * When we have tif_rawdata reference directly into the memory mapped file
			 * we need to be pretty careful about how we use the rawdata.  It is not
			 * a general purpose working buffer as it normally otherwise is.  So we
			 * keep track of this fact to avoid using it improperly.
			 */
			tif->tif_flags |= TIFF_BUFFERMMAP;
		} else {
			/*
			 * Expand raw data buffer, if needed, to hold data
			 * strip coming from file (perhaps should set upper
			 * bound on the size of a buffer we'll use?).
			 */
			tmsize_t bytecountm;
			bytecountm=(tmsize_t)bytecount;
			if ((uint64)bytecountm!=bytecount)
			{
				TIFFErrorExt(tif->tif_clientdata,module,"Integer overflow");
				return(0);
			}
			if (bytecountm > tif->tif_rawdatasize) {
				tif->tif_curstrip = NOSTRIP;
				if ((tif->tif_flags & TIFF_MYBUFFER) == 0) {
					TIFFErrorExt(tif->tif_clientdata, module,
					    "Data buffer too small to hold strip %lu",
					    (unsigned long) strip);
					return (0);
				}
				if (!TIFFReadBufferSetup(tif, 0, bytecountm))
					return (0);
			}
			if (tif->tif_flags&TIFF_BUFFERMMAP) {
				tif->tif_curstrip = NOSTRIP;
				if (!TIFFReadBufferSetup(tif, 0, bytecountm))
					return (0);
			}
			if (TIFFReadRawStrip1(tif, strip, tif->tif_rawdata,
				bytecountm, module) != bytecountm)
				return (0);

                        tif->tif_rawdataoff = 0;
                        tif->tif_rawdataloaded = bytecountm;
                        
			if (!isFillOrder(tif, td->td_fillorder) &&
			    (tif->tif_flags & TIFF_NOBITREV) == 0)
				TIFFReverseBits(tif->tif_rawdata, bytecountm);
                }
	}
	return (TIFFStartStrip(tif, strip));
}

Project: libtiff

TIFFFillStripPartial( TIFF *tif, int strip, tmsize_t read_ahead, int restart )
{
	static const char module[] = "TIFFFillStripPartial";
	register TIFFDirectory *td = &tif->tif_dir;
        tmsize_t unused_data;
        uint64 read_offset;
        tmsize_t cc, to_read;
        /* tmsize_t bytecountm; */
        
        if (!_TIFFFillStriles( tif ) || !tif->tif_dir.td_stripbytecount)
            return 0;
        
        /*
         * Expand raw data buffer, if needed, to hold data
         * strip coming from file (perhaps should set upper
         * bound on the size of a buffer we'll use?).
         */

        /* bytecountm=(tmsize_t) td->td_stripbytecount[strip]; */
        if (read_ahead*2 > tif->tif_rawdatasize) {
                assert( restart );
                
                tif->tif_curstrip = NOSTRIP;
                if ((tif->tif_flags & TIFF_MYBUFFER) == 0) {
                        TIFFErrorExt(tif->tif_clientdata, module,
                                     "Data buffer too small to hold part of strip %lu",
                                     (unsigned long) strip);
                        return (0);
                }
                if (!TIFFReadBufferSetup(tif, 0, read_ahead*2))
                        return (0);
        }

        if( restart )
        {
                tif->tif_rawdataloaded = 0;
                tif->tif_rawdataoff = 0;
        }

        /*
        ** If we are reading more data, move any unused data to the
        ** start of the buffer.
        */
        if( tif->tif_rawdataloaded > 0 )
                unused_data = tif->tif_rawdataloaded - (tif->tif_rawcp - tif->tif_rawdata);
        else
                unused_data = 0;
        
        if( unused_data > 0 )
        {
		assert((tif->tif_flags&TIFF_BUFFERMMAP)==0);
                memmove( tif->tif_rawdata, tif->tif_rawcp, unused_data );
        }

        /*
        ** Seek to the point in the file where more data should be read.
        */
        read_offset = td->td_stripoffset[strip]
                + tif->tif_rawdataoff + tif->tif_rawdataloaded;

        if (!SeekOK(tif, read_offset)) {
                TIFFErrorExt(tif->tif_clientdata, module,
                             "Seek error at scanline %lu, strip %lu",
                             (unsigned long) tif->tif_row, (unsigned long) strip);
                return 0;
        }

        /*
        ** How much do we want to read?
        */
        to_read = tif->tif_rawdatasize - unused_data;
        if( (uint64) to_read > td->td_stripbytecount[strip] 
            - tif->tif_rawdataoff - tif->tif_rawdataloaded )
        {
                to_read = (tmsize_t) td->td_stripbytecount[strip]
                        - tif->tif_rawdataoff - tif->tif_rawdataloaded;
        }

	assert((tif->tif_flags&TIFF_BUFFERMMAP)==0);
        cc = TIFFReadFile(tif, tif->tif_rawdata + unused_data, to_read);

        if (cc != to_read) {
#if defined(__WIN32__) && (defined(_MSC_VER) || defined(__MINGW32__))
                TIFFErrorExt(tif->tif_clientdata, module,
                             "Read error at scanline %lu; got %I64u bytes, expected %I64u",
                             (unsigned long) tif->tif_row,
                             (unsigned __int64) cc,
                             (unsigned __int64) to_read);
#else
                TIFFErrorExt(tif->tif_clientdata, module,
                             "Read error at scanline %lu; got %llu bytes, expected %llu",
                             (unsigned long) tif->tif_row,
                             (unsigned long long) cc,
                             (unsigned long long) to_read);
#endif
                return 0;
        }
        
        tif->tif_rawdataoff = tif->tif_rawdataoff + tif->tif_rawdataloaded - unused_data ;
        tif->tif_rawdataloaded = unused_data + to_read;

        tif->tif_rawcp = tif->tif_rawdata;
                        
        if (!isFillOrder(tif, td->td_fillorder) &&
            (tif->tif_flags & TIFF_NOBITREV) == 0) {
		assert((tif->tif_flags&TIFF_BUFFERMMAP)==0);
                TIFFReverseBits(tif->tif_rawdata + unused_data, to_read );
	}

        /*
        ** When starting a strip from the beginning we need to
        ** restart the decoder.
        */
        if( restart )
                return TIFFStartStrip(tif, strip);
        else
                return 1;
}

Project: libtiff
File: tif_read.c

_TIFFSwab64BitData(TIFF* tif, uint8* buf, tmsize_t cc)
{
    (void) tif;
    assert((cc & 7) == 0);
    TIFFSwabArrayOfDouble((double*) buf, cc/8);
}