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EnGarde Secure Linux 3.0.20 (Community Edition branch)
08-21-2008
Engineered from the ground-up with specific regard to security, EnGarde Secure Linux incorporates intrusion alert capabilities, a complete suite of e- business applications using AllCommerce, improved authentication and access control, strong cryptography, and complete SSL secure Web-based administration capabilities. EnGarde protects against many forms of attack, not just a particular form of vulnerability. It is also not just a repackaged version of another distribution that claims to be secure. EnGarde is a collection of best-of-breed applications from many sources tuned to provide exactly what is necessary to maintain a secure Internet presence. Featuring the Linux Intrusion Detection System integrated into its design, as well as Web-manageable Tripwire, tools from many Open Source security projects including Openwall, snort network intrusion detection system, and extensive host security improvements, EnGarde Secure Linux strives to be the most secure, yet functional, Linux distribution to date. License: GNU General Public License (GPL) Changes:|
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GETENV(3) Linux Programmer's Manual GETENV(3) NAME
getenv, secure_getenv - get an environment variable SYNOPSIS
#include <stdlib.h> char *getenv(const char *name); char *secure_getenv(const char *name); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): secure_getenv(): _GNU_SOURCE DESCRIPTION
The getenv() function searches the environment list to find the environment variable name, and returns a pointer to the corresponding value string. The GNU-specific secure_getenv() function is just like getenv() except that it returns NULL in cases where "secure execution" is required. Secure execution is required if one of the following conditions was true when the program run by the calling process was loaded: * the process's effective user ID did not match its real user ID or the process's effective group ID did not match its real group ID (typ- ically this is the result of executing a set-user-ID or set-group-ID program); * the effective capability bit was set on the executable file; or * the process has a nonempty permitted capability set. Secure execution may also be required if triggered by some Linux security modules. The secure_getenv() function is intended for use in general-purpose libraries to avoid vulnerabilities that could occur if set-user-ID or set-group-ID programs accidentally trusted the environment. RETURN VALUE
The getenv() function returns a pointer to the value in the environment, or NULL if there is no match. VERSIONS
secure_getenv() first appeared in glibc 2.17. ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7). +--------------------------+---------------+-------------+ |Interface | Attribute | Value | +--------------------------+---------------+-------------+ |getenv(), secure_getenv() | Thread safety | MT-Safe env | +--------------------------+---------------+-------------+ CONFORMING TO
getenv(): POSIX.1-2001, POSIX.1-2008, C89, C99, SVr4, 4.3BSD. secure_getenv() is a GNU extension. NOTES
The strings in the environment list are of the form name=value. As typically implemented, getenv() returns a pointer to a string within the environment list. The caller must take care not to modify this string, since that would change the environment of the process. The implementation of getenv() is not required to be reentrant. The string pointed to by the return value of getenv() may be statically allocated, and can be modified by a subsequent call to getenv(), putenv(3), setenv(3), or unsetenv(3). The "secure execution" mode of secure_getenv() is controlled by the AT_SECURE flag contained in the auxiliary vector passed from the kernel to user space. SEE ALSO
clearenv(3), getauxval(3), putenv(3), setenv(3), unsetenv(3), capabilities(7), environ(7) COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/. GNU
2017-09-15 GETENV(3)