centos 6
race weakness #30

5

Weakness Breakdown


Definition:

A race condition exists when parallel code accesses shared data without proper coordination. An attack that uses a race-condition weakness takes advantage of the unsafe data access to manipulate how one of the parallel sections of code reacts. Even though each process runs as intended, the outcome is unexpected. For example, consider a bank service that depends on an encryption key that it reads from a known location. An independent cryptography service is responsible for generating the key and placing it where the bank is expected to read it in a timely manner. If the bank and cryptography services do not coordinate with each other, then the bank may read a blank encryption key before cryptography writes the key to the location. This can effectively turn off all encryption for the bank without either service, or the administrator, knowing that something has gone wrong.

Warning code(s):

This accepts filename arguments; if an attacker can move those files, a race condition results..

File Name:

kdepimlibs-4.3.4/kioslave/sieve/sieve.cpp

Context:

The highlighted line of code below is the trigger point of this particular Centos 6 race weakness.

 	infoMessage(i18n("Deleting file..."));

	QString filename = url.fileName( KUrl::ObeyTrailingSlash );

	if (filename.isEmpty()) {
		error(ERR_MALFORMED_URL, url.prettyUrl());
		return;
	}

	if (!sendData("DELETESCRIPT \"" + filename.toUtf8() + "\""))
		return;

	if (operationSuccessful())
		ksDebug << "Script deletion successful." << endl;
	else {
		error(ERR_INTERNAL_SERVER, i18n("The server would not delete the file."));
		return;
	}

	infoMessage(i18nc("file removal complete", "Done."));

	finished();
}

void kio_sieveProtocol::chmod(const KUrl& url, int permissions)
{
  switch ( permissions ) {
  case 0700: // activate
    activate(url);
    break;
  case 0600: // deactivate
    deactivate();
    break;
  default: // unsupported
    error(ERR_CANNOT_CHMOD, i18n("Cannot chmod to anything but 0700 (active) or 0600 (inactive script)."));
    return;
  }

  finished();
}

void kio_sieveProtocol::urlStat(const KUrl& url)
{
	changeCheck( url );
	if (!connect())
		return;

	UDSEntry entry;

	QString filename = url.fileName( KUrl::ObeyTrailingSlash ); 

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