static int readContigStripsIntoBuffer (TIFF* in, uint8* buf)
 {
         uint8* bufp = buf;
         int32  bytes_read = 0;
        uint16 strip, nstrips   = TIFFNumberOfStrips(in);
         uint32 stripsize = TIFFStripSize(in);
         uint32 rows = 0;
         uint32 rps = TIFFGetFieldDefaulted(in, TIFFTAG_ROWSPERSTRIP, &rps);
        tsize_t scanline_size = TIFFScanlineSize(in);

        if (scanline_size == 0) {
                TIFFError("", "TIFF scanline size is zero!");    
                return 0;
        }

        for (strip = 0; strip < nstrips; strip++) {
                bytes_read = TIFFReadEncodedStrip (in, strip, bufp, -1);
                rows = bytes_read / scanline_size;
                if ((strip < (nstrips - 1)) && (bytes_read != (int32)stripsize))
                        TIFFError("", "Strip %d: read %lu bytes, strip size %lu",
                                  (int)strip + 1, (unsigned long) bytes_read,
                                  (unsigned long)stripsize);

                if (bytes_read < 0 && !ignore) {
                        TIFFError("", "Error reading strip %lu after %lu rows",
                                  (unsigned long) strip, (unsigned long)rows);
                        return 0;
                }
                bufp += bytes_read;
        }

        return 1;
} /* end readContigStripsIntoBuffer */

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.