pam_env.so [
debug
] [
conffile=conf-file
] [
envfile=env-file
] [
readenv=0|1
] [
user_envfile=env-file
] [
user_readenv=0|1
]
The pam_env PAM module allows the (un)setting of environment variables. Supported is the use of previously set environment variables as well as PAM_ITEMs such as PAM_RHOST.
By default rules for (un)setting of variables is taken from the
config file /etc/security/pam_env.conf if
no other file is specified.
This module can also parse a file with simple
KEY=VAL pairs on separate lines
(/etc/environment by default). You can
change the default file to parse, with the envfile
flag and turn it on or off by setting the readenv
flag to 1 or 0 respectively.
Since setting of PAM environment variables can have side effects to other modules, this module should be the last one on the stack.
The /etc/security/pam_env.conf file specifies
the environment variables to be set, unset or modified by
pam_env(8).
When someone logs in, this file is read and the environment
variables are set according.
Each line starts with the variable name, there are then two possible options for each variable DEFAULT and OVERRIDE. DEFAULT allows and administrator to set the value of the variable to some default value, if none is supplied then the empty string is assumed. The OVERRIDE option tells pam_env that it should enter in its value (overriding the default value) if there is one to use. OVERRIDE is not used, "" is assumed and no override will be done.
VARIABLE
[DEFAULT=[value]]
[OVERRIDE=[value]]
(Possibly non-existent) environment variables may be used in values using the ${string} syntax and (possibly non-existent) PAM_ITEMs may be used in values using the @{string} syntax. Both the $ and @ characters can be backslash escaped to be used as literal values values can be delimited with "", escaped " not supported. Note that many environment variables that you would like to use may not be set by the time the module is called. For example, HOME is used below several times, but many PAM applications don't make it available by the time you need it.
The "#" character at start of line (no space at front) can be used to mark this line as a comment line.
The /etc/environment file specifies
the environment variables to be set. The file must consist of simple
NAME=VALUE pairs on separate lines.
The pam_env(8)
module will read the file after the pam_env.conf
file.
conffile=/path/to/pam_env.conf
Indicate an alternative pam_env.conf
style configuration file to override the default. This can
be useful when different services need different environments.
debug
A lot of debug information is printed with syslog(3).
envfile=/path/to/environment
Indicate an alternative environment
file to override the default. This can be useful when different
services need different environments.
readenv=0|1
Turns on or off the reading of the file specified by envfile (0 is off, 1 is on). By default this option is on.
user_envfile=filename
Indicate an alternative .pam_environment
file to override the default. This can be useful when different
services need different environments. The filename is relative to
the user home directory.
user_readenv=0|1
Turns on or off the reading of the user specific environment file. 0 is off, 1 is on. By default this option is off as user supplied environment variables in the PAM environment could affect behavior of subsequent modules in the stack without the consent of the system administrator.
Not all relevant data or options could be gotten.
Memory buffer error.
No pam_env.conf and environment file was found.
Environment variables were set.
/etc/security/pam_env.confDefault configuration file
/etc/environmentDefault environment file
$HOME/.pam_environmentUser specific environment file
These are some example lines which might be specified in
/etc/security/pam_env.conf.
Set the REMOTEHOST variable for any hosts that are remote, default to "localhost" rather than not being set at all
REMOTEHOST DEFAULT=localhost OVERRIDE=@{PAM_RHOST}
Set the DISPLAY variable if it seems reasonable
DISPLAY DEFAULT=${REMOTEHOST}:0.0 OVERRIDE=${DISPLAY}
Now some simple variables
PAGER DEFAULT=less
MANPAGER DEFAULT=less
LESS DEFAULT="M q e h15 z23 b80"
NNTPSERVER DEFAULT=localhost
PATH DEFAULT=${HOME}/bin:/usr/local/bin:/bin\
:/usr/bin:/usr/local/bin/X11:/usr/bin/X11
Silly examples of escaped variables, just to show how they work.
DOLLAR DEFAULT=\$
DOLLARDOLLAR DEFAULT= OVERRIDE=\$${DOLLAR}
DOLLARPLUS DEFAULT=\${REMOTEHOST}${REMOTEHOST}
ATSIGN DEFAULT="" OVERRIDE=\@