alpine 3.7
race weakness #36

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:

icinga2/src/icinga2-2.8.2/lib/base/utility.cpp

Context:

The highlighted line of code below is the trigger point of this particular Alpine 3.7 race weakness.

 #ifndef _WIN32
	fd = mkstemp(&targetPath[0]);
#else /* _WIN32 */
	fd = MksTemp(&targetPath[0]);
#endif /*_WIN32*/

	if (fd < 0) {
		BOOST_THROW_EXCEPTION(posix_error()
		    << boost::errinfo_api_function("mkstemp")
		    << boost::errinfo_errno(errno)
		    << boost::errinfo_file_name(path));
	}

	try {
		fp.open(&targetPath[0], std::ios_base::trunc | std::ios_base::out);
	} catch (const std::fstream::failure& e) {
		close(fd);
		throw;
	}

	close(fd);

	String resultPath = String(targetPath.begin(), targetPath.end() - 1);

	if (chmod(resultPath.CStr(), mode) < 0) {
		BOOST_THROW_EXCEPTION(posix_error()
		    << boost::errinfo_api_function("chmod")
		    << boost::errinfo_errno(errno)
		    << boost::errinfo_file_name(resultPath));
	}

	return resultPath;
}

#ifdef _WIN32
/* mkstemp extracted from libc/sysdeps/posix/tempname.c.  Copyright
   (C) 1991-1999, 2000, 2001, 2006 Free Software Foundation, Inc.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.  */

#define _O_EXCL 0x0400
#define _O_CREAT 0x0100
#define _O_RDWR 0x0002
#define O_EXCL _O_EXCL
#define O_CREAT	_O_CREAT
#define O_RDWR _O_RDWR
 

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