doas/doas-6.3p6/doas.conf.5

.\" $OpenBSD: doas.conf.5,v 1.31 2016/12/05 10:58:07 schwarze Exp $
.\"
.\"Copyright (c) 2015 Ted Unangst <tedu@openbsd.org>
.\"
.\"Permission to use, copy, modify, and distribute this software for any
.\"purpose with or without fee is hereby granted, provided that the above
.\"copyright notice and this permission notice appear in all copies.
.\"
.\"THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\"WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\"MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\"ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\"WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\"ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\"OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.Dd $Mdocdate: December 5 2016 $
.Dt DOAS.CONF 5
.Os
.Sh NAME
.Nm doas.conf
.Nd doas configuration file
.Sh SYNOPSIS
.Nm @DOAS_CONF@
.Sh DESCRIPTION
The
.Xr doas 1
utility executes commands as other users according to the rules
in the
.Nm
configuration file.
.Pp
The rules have the following format:
.Bd -ragged -offset indent
.Ic permit Ns | Ns Ic deny
.Op Ar options
.Ar identity
.Op Ic as Ar target
.Op Ic cmd Ar command Op Ic args No ...
.Ed
.Pp
Rules consist of the following parts:
.Bl -tag -width 11n
.It Ic permit Ns | Ns Ic deny
The action to be taken if this rule matches.
.It Ar options
Options are:
.Bl -tag -width keepenv
.It Ic nopass
The user is not required to enter a password.
.It Ic nolog
Do not log successful command execution to
.Xr syslogd.
.It Ic persist
After the user successfully authenticates, do not ask for a password
again for some time. Works on OpenBSD only, persist is not available on Linux or FreeBSD.
.It Ic keepenv
The user's environment is maintained.
The default is to reset the environment, except for the variables
.Ev DISPLAY
and
.Ev TERM .

Note: In order to be able to run most desktop (GUI) applications, the user needs to
have the keepenv keyword specified. If keepenv is not specified then key elements, like
the user's $HOME variable, will be reset and cause the GUI application to crash.
Users who only need to run command line applications can usually get away without
keepenv. When in doubt, try to avoid using keepenv as it is less secure to have
environment variables passed to privileged users.

Note: The target user's PATH variable can be set at compile time by adjusting the
GLOBAL_PATH variable in doas's Makefile. By default, the target user's path will
be set to "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:"
.It Ic setenv { Oo Ar variable ... Oc Oo Ar variable=value ... Oc Ic }
In addition to the variables mentioned above, keep the space-separated
specified variables.
Variables may also be removed with a leading
.Sq -
or set using the latter syntax.
If the first character of
.Ar value
is a
.Ql $
then the value to be set is taken from the existing environment
variable of the same name.
.El
.It Ar identity
The username to match.
Groups may be specified by prepending a colon
.Pq Sq \&: .
Numeric IDs are also accepted.
.It Ic as Ar target
The target user the running user is allowed to run the command as.
The default is all users.
.It Ic cmd Ar command
The command the user is allowed or denied to run.
The default is all commands.
Be advised that it is best to specify absolute paths.
If a relative path is specified, only a restricted
.Ev PATH
will be searched.
.It Ic args Op Ar argument ...
Arguments to command.
The command arguments provided by the user need to match those specified.
The keyword
.Ic args
alone means that command must be run without any arguments.
.El
.Pp
The last matching rule determines the action taken.
If no rule matches, the action is denied.
.Pp
Comments can be put anywhere in the file using a hash mark
.Pq Sq # ,
and extend to the end of the current line.
.Pp
The following quoting rules apply:
.Bl -dash
.It
The text between a pair of double quotes
.Pq Sq \&"
is taken as is.
.It
The backslash character
.Pq Sq \e
escapes the next character, including new line characters, outside comments;
as a result, comments may not be extended over multiple lines.
.It
If quotes or backslashes are used in a word,
it is not considered a keyword.
.El
.Sh NOTES
To make editing the doas.conf file safer, a convenience script called
vidoas is included with the doas software. This script can be run as
the root user (or via doas or sudo) and automatically checks the syntax of the doas.conf file
before installing it on the system.

Please take note that it is a bad idea to assign permission to users
implicitly, even if blocking/denying exceptions are made. For instance, try
to avoid using rules like
.Bd -literal -offset indent
permit susan as
deny susan as root

.Ed
The above example uses two rules to permit Susan to switch to any user, except
root. This is dangerous for two reasons. First, it means if new users,
including ones with admin access, are added to the system later then
Susan can use their accounts. It also means if the file is truncated or
accessed while being updated the doas program may read the first rule
before the second has been written, giving Susan access to everything,
including the root account. The better approach to is explicity allow Susan
to access only specific accounts she needs to use.

Entries in the doas.conf file must end with a newline character to
indicate where a rule ends. Most text editors will add a newline or
end of line character for you, however not all tools do. Please make
sure each rule in your doas.conf file ends with a newline (Enter)
character. Otherwise syntax checks will fail with an error
"syntax error at line..."

.Sh EXAMPLES
The following example permits users in group wsrc to build ports;
wheel to execute commands as any user while keeping the environment
variables
.Ev PS1
and
.Ev SSH_AUTH_SOCK
and
unsetting
.Ev ENV ;
permits tedu to run procmap as root without a password;
and additionally permits root to run unrestricted commands as itself.
.Bd -literal -offset indent
# Non-exhaustive list of variables needed to
# build release(8) and ports(7)
permit nopass setenv { \e
        FTPMODE PKG_CACHE PKG_PATH SM_PATH SSH_AUTH_SOCK \e
        DESTDIR DISTDIR FETCH_CMD FLAVOR GROUP MAKE MAKECONF \e
        MULTI_PACKAGES NOMAN OKAY_FILES OWNER PKG_DBDIR \e
        PKG_DESTDIR PKG_TMPDIR PORTSDIR RELEASEDIR SHARED_ONLY \e
        SUBPACKAGE WRKOBJDIR SUDO_PORT_V1 } :wsrc
permit setenv { -ENV PS1=$DOAS_PS1 SSH_AUTH_SOCK } :wheel
permit nopass tedu as root cmd /usr/sbin/procmap
permit nopass keepenv root as root
.Ed
.Sh SEE ALSO
.Xr doas 1
.Sh HISTORY
The
.Nm
configuration file first appeared in
.Ox 5.8 .
.Sh AUTHORS
.An Ted Unangst Aq Mt tedu@openbsd.org