Fix CVE-2016-1531

[exim.git] / src / src / environment.c

/*************************************************
*     Exim - an Internet mail transport agent    *
*************************************************/

/* Copyright (c) Heiko Schlittermann 2016
 * hs@schlittermann.de
 * See the file NOTICE for conditions of use and distribution.
 */

#include "exim.h"

/* The cleanup_environment() function is used during the startup phase
of the Exim process, right after reading the configurations main
part, before any expansions take place. It retains the environment
variables we trust (via the keep_environment option) and allows to
set additional variables (via add_environment).

Returns:    TRUE if successful
            FALSE otherwise
*/

BOOL
cleanup_environment()
{
if (!keep_environment || *keep_environment == '\0')
  clearenv();
else if (Ustrcmp(keep_environment, "*") != 0)
  {
  uschar **p;
  if (environ) for (p = USS environ; *p; /* see below */)
    {
    uschar *name = string_copyn(*p, US Ustrchr(*p, '=') - *p);

    if (OK != match_isinlist(name, CUSS &keep_environment,
        0, NULL, NULL, MCL_NOEXPAND, FALSE, NULL))
      if (unsetenv(CS name) < 0) return FALSE;
      else /* nothing */;
    else
      p++;

    store_reset(name);
    }
  }
if (add_environment)
  {
    uschar *p;
    int sep = 0;
    const uschar* envlist = add_environment;
    while ((p = string_nextinlist(&envlist, &sep, NULL, 0)))
        putenv(CS p);
  }

  return TRUE;
}