alpine 3.8
race weakness #12

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 or change the link content, a race condition results. Also, it does not terminate with ASCII NUL..

File Name:

augeas/src/augeas-1.10.1/gnulib/tests/test-readlink.c

Context:

The highlighted line of code below is the trigger point of this particular Alpine 3.8 race weakness.

 /* Tests of readlink.
   Copyright (C) 2009-2017 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

/* Written by Eric Blake <ebb9@byu.net>, 2009.  */

#include <config.h>

#include <unistd.h>

#include "signature.h"
SIGNATURE_CHECK (readlink, ssize_t, (char const *, char *, size_t));

#include <fcntl.h>
#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>

#include "ignore-value.h"
#include "macros.h"

#define BASE "test-readlink.t"

#include "test-readlink.h"

int
main (void)
{
  /* Remove any leftovers from a previous partial run.  */
  ignore_value (system ("rm -rf " BASE "*"));

  return test_readlink (readlink, true);
} 

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