wget/lib/secure_getenv.c

55 lines
2.0 KiB
C

/* Look up an environment variable, returning NULL in insecure situations.
Copyright 2013-2019 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/>. */
#include <config.h>
#include <stdlib.h>
#if !HAVE___SECURE_GETENV
# if HAVE_ISSETUGID || (HAVE_GETUID && HAVE_GETEUID && HAVE_GETGID && HAVE_GETEGID)
# include <unistd.h>
# endif
#endif
char *
secure_getenv (char const *name)
{
#if HAVE___SECURE_GETENV /* glibc */
return __secure_getenv (name);
#elif HAVE_ISSETUGID /* OS X, FreeBSD, NetBSD, OpenBSD */
if (issetugid ())
return NULL;
return getenv (name);
#elif HAVE_GETUID && HAVE_GETEUID && HAVE_GETGID && HAVE_GETEGID /* other Unix */
if (geteuid () != getuid () || getegid () != getgid ())
return NULL;
return getenv (name);
#elif defined _WIN32 && ! defined __CYGWIN__ /* native Windows */
/* On native Windows, there is no such concept as setuid or setgid binaries.
- Programs launched as system services have high privileges, but they don't
inherit environment variables from a user.
- Programs launched by a user with "Run as Administrator" have high
privileges and use the environment variables, but the user has been asked
whether he agrees.
- Programs launched by a user without "Run as Administrator" cannot gain
high privileges, therefore there is no risk. */
return getenv (name);
#else
return NULL;
#endif
}