kio

kshred.cpp

00001 /*--------------------------------------------------------------------------*
00002  KShred.h  Copyright (c) 2000 MieTerra LLC.
00003  Credits:  Andreas F. Pour <bugs@mieterra.com>
00004 
00005 Permission is hereby granted, free of charge, to any person obtaining a copy
00006 of this software and associated documentation files (the "Software"), to deal
00007 in the Software without restriction, including without limitation the rights
00008 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00009 copies of the Software, and to permit persons to whom the Software is
00010 furnished to do so, subject to the following conditions:
00011 
00012 The above copyright notice and this permission notice shall be included in
00013 all copies or substantial portions of the Software.
00014 
00015 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00016 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00017 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
00018 AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
00019 AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
00020 CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00021 */
00022 
00023 #include "kshred.h"
00024 #include <time.h>
00025 #include <klocale.h>
00026 #include <kdebug.h>
00027 #include <stdlib.h>
00028 #include <kapplication.h>
00029 
00030 // antlarr: KDE 4: Make it const QString &
00031 KShred::KShred(QString fileName)
00032 {
00033   if (fileName.isEmpty())
00034   {
00035     kdError() << "KShred: missing file name in constructor" << endl;
00036     file = 0L;
00037   }
00038   else
00039   {
00040     file = new QFile();
00041     file->setName(fileName);
00042     if (!file->open(IO_ReadWrite))
00043     {
00044       kdError() << "KShred: cannot open file '" << fileName.local8Bit().data() << "' for writing\n" << endl;
00045       file = 0L;
00046       fileSize = 0;
00047     }
00048     else
00049       fileSize = file->size();
00050 
00051     totalBytes    = 0;
00052     bytesWritten  = 0;
00053     lastSignalled = 0;
00054     tbpc          = 0;
00055     fspc          = 0;
00056   }
00057 }
00058 
00059 
00060 KShred::~KShred()
00061 {
00062   if (file != 0L)
00063     delete file;
00064 }
00065 
00066 
00067 bool
00068 KShred::fill1s()
00069 {
00070   return fillbyte(0xFF);
00071 }
00072 
00073 
00074 bool
00075 KShred::fill0s()
00076 {
00077   return fillbyte(0x0);
00078 }
00079 
00080 
00081 bool
00082 KShred::fillbyte(unsigned int byte)
00083 {
00084   if (file == 0L)
00085     return false;
00086   unsigned char buff[4096];
00087   memset((void *) buff, byte, 4096);
00088 
00089   unsigned int n;
00090   for (unsigned int todo = fileSize; todo > 0; todo -= n)
00091   {
00092     n = (todo > 4096 ? 4096 : todo);
00093     if (!writeData(buff, n))
00094       return false;
00095   }
00096   if (!flush())
00097     return false;
00098   return file->at(0);
00099 }
00100 
00101 
00102 bool
00103 KShred::fillpattern(unsigned char *data, unsigned int size)
00104 {
00105   if (file == 0L)
00106     return false;
00107 
00108   unsigned int n;
00109   for (unsigned int todo = fileSize; todo > 0; todo -= n)
00110   {
00111     n = (todo > size ? size : todo);
00112     if (!writeData(data, n))
00113       return false;
00114   }
00115   if (!flush())
00116     return false;
00117   return file->at(0);
00118 }
00119 
00120 
00121 bool
00122 KShred::fillrandom()
00123 {
00124   if (file == 0L)
00125     return false;
00126 
00127   long int buff[4096 / sizeof(long int)];
00128   unsigned int n;
00129 
00130   for (unsigned int todo = fileSize; todo > 0; todo -= n)
00131   {
00132     n = (todo > 4096 ? 4096 : todo);
00133     // assumes that 4096 is a multipe of sizeof(long int)
00134     int limit = (n + sizeof(long int) - 1) / sizeof(long int);
00135     for (int i = 0; i < limit; i++)
00136       buff[i] = kapp->random();
00137 
00138     if (!writeData((unsigned char *) buff, n))
00139       return false;
00140   }
00141   if (!flush())
00142     return false;
00143   return file->at(0);
00144 }
00145 
00146 
00147 // antlarr: KDE 4: Make it const QString &
00148 bool
00149 KShred::shred(QString fileName)
00150 {
00151   if (fileName.isEmpty())
00152     return false;
00153 
00154   KShred shredder(fileName);
00155   return shredder.shred();
00156 }
00157 
00158 
00159 bool
00160 KShred::writeData(unsigned char *data, unsigned int size)
00161 {
00162   unsigned int ret                  = 0;
00163 
00164   // write 'data' of size 'size' to the file
00165   while ((ret < size) && (file->putch((int) data[ret]) >= 0))
00166     ret++;
00167 
00168   if ((totalBytes > 0) && (ret > 0))
00169   {
00170     if (tbpc == 0)
00171     {
00172       tbpc = ((unsigned int) (totalBytes / 100)) == 0 ? 1 : totalBytes / 100;
00173       fspc = ((unsigned int) (fileSize / 100)) == 0 ? 1 : fileSize / 100;
00174     }
00175     bytesWritten += ret;
00176     unsigned int pc = (unsigned int) (bytesWritten / tbpc);
00177     if (pc > lastSignalled)
00178     {
00179       emit processedSize(fspc * pc);
00180       lastSignalled = pc;
00181     }
00182   }
00183   return ret == size;
00184 }
00185 
00186 
00187 bool
00188 KShred::flush()
00189 {
00190   if (file == 0L)
00191     return false;
00192 
00193   file->flush();
00194   return (fsync(file->handle()) == 0);
00195 }
00196 
00197 
00198 // shred the file, then close and remove it
00199 //
00200 // UPDATED: this function now uses 35 passes based on the the article
00201 // Peter Gutmann, "Secure Deletion of Data from Magnetic and Solid-State
00202 // Memory", first published in the Sixth USENIX Security Symposium
00203 // Proceedings, San Jose, CA, July 22-25, 1996 (available online at
00204 // http://rootprompt.org/article.php3?article=473)
00205 
00206 bool
00207 KShred::shred()
00208 {
00209   unsigned char p[6][3] = {{'\222', '\111', '\044'}, {'\111', '\044', '\222'},
00210                            {'\044', '\222', '\111'}, {'\155', '\266', '\333'},
00211                            {'\266', '\333', '\155'}, {'\333', '\155', '\266'}};
00212   QString msg = i18n("Shredding:  pass %1 of 35");
00213 
00214   emit processedSize(0);
00215 
00216   // thirty-five times writing the entire file size
00217   totalBytes = fileSize * 35;
00218   int iteration = 1;
00219 
00220   for (int ctr = 0; ctr < 4; ctr++)
00221     if (!fillrandom())
00222       return false;
00223     else
00224     {
00225       emit infoMessage(msg.arg(iteration));
00226     }
00227 
00228   if (!fillbyte((unsigned int) 0x55))     // '0x55' is 01010101
00229     return false;
00230   emit infoMessage(msg.arg(iteration));
00231 
00232   if (!fillbyte((unsigned int) 0xAA))     // '0xAA' is 10101010
00233     return false;
00234   emit infoMessage(msg.arg(iteration));
00235 
00236   for (unsigned int ctr = 0; ctr < 3; ctr++)
00237     if (!fillpattern(p[ctr], 3))  // '0x92', '0x49', '0x24'
00238       return false;
00239     else
00240     {
00241       emit infoMessage(msg.arg(iteration));
00242     }
00243 
00244   for (unsigned int ctr = 0; ctr <= 255 ; ctr += 17)
00245     if (!fillbyte(ctr))    // sequence of '0x00', '0x11', ..., '0xFF'
00246       return false;
00247     else
00248     {
00249       emit infoMessage(msg.arg(iteration));
00250     }
00251 
00252   for (unsigned int ctr = 0; ctr < 6; ctr++)
00253     if (!fillpattern(p[ctr], 3))  // '0x92', '0x49', '0x24'
00254       return false;
00255     else
00256     {
00257       emit infoMessage(msg.arg(iteration));
00258     }
00259 
00260   for (int ctr = 0; ctr < 4; ctr++)
00261     if (!fillrandom())
00262       return false;
00263     else
00264     {
00265       emit infoMessage(msg.arg(iteration));
00266     }
00267 
00268   if (!file->remove())
00269     return false;
00270   file = 0L;
00271   emit processedSize(fileSize);
00272   return true;
00273 }
00274 
00275 #include "kshred.moc"
00276
kio

kshred.cpp

kio

API Reference
