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please.ini(5) User Manual please.ini(5)

NAME

please.ini - configuration file for access

DESCRIPTION

The please.ini file contains one or more [sections] that hold ACL for users of the please and pleaseedit programs.

please.ini is an ini file, sections can be named with a short description of what the section provides. You may then find this helpful when listing rights with please -l.

Rules are read and applied in the order they are presented in the configuration file. For example, if the user matches a permit rule to run a command in an early section, but in a later section matches criteria for a deny and no further matches, then the user will not be permitted to run that command. The last match wins.

The properties permitted are described below and should appear at most once per section. If a property is used more than once in a section, the last one will be used.

SECTION OPTIONS

[section-name]
section name, shown in list mode
read ini file, and continue to next section
read .ini files in directory, and continue to next section, if the directory does not exist config parse will fail

Sections with a name starting default will retain match actions including implicit permit, therefore setting permit=false in the default block and permit=true elsewhere is advised.

MATCHES

mandatory, the user or group (see below) to match against
user to execute or list as, defaults to root
requires that the user runs with --group to run or edit with the match
the regular expression that the command or edit path matches against, defaults to ^$
will add HHMMSS as 00:00:00 to the date if not given, defaults to never
will add 23:59:59 to the date if not given, defaults to never
regex to match a date string with
this section’s mode behaviour, defaults to run, edit = pleaseedit entry, list = user access rights listing
defaults to false, when true, the name (above) refers to a group rather than a user
permitted hostnames where this may apply. A hostname defined as any or localhost will always match. Defaults to localhost
permitted directories to run within
allow environments that match regex to optionally pass through
configure a : separated directory list to locate the binary to execute, does not configure a PATH environment and is searched as the user running please, not as the target user (no plans to change that at present)

regex is a regular expression, %{USER} will expand to the user who is currently running please, %{HOSTNAME} expands to the hostname. See below for examples. Other %{} expansions may be added at a later date.

Spaces within arguments will be substituted as `\ ' (backslash space). Use ^/bin/echo hello\\ world$ to match /bin/echo “hello world”, note that \ is a regex escape character so it must be escaped, therefore matching a space becomes `\\ ' (backslash backslash space).

To match a \ (backslash), the hex code \x5c can be used.

To match the string %{USER}, the sequence \x25\{USER\} can be used.

Rules starting exact are string matches and not regex processed and take precedence over regex matches.

only permit a user/group name that matches exactly
only permit a hostname that matches exactly
only permit a target that matches exactly
requires that the user runs with --group to run or edit as groupname
only permit a command rule that matches exactly
only permit a dir that matches exactly

ACTIONS

permit or disallow the entry, defaults to true
if entry matches, require a password, defaults to true
length of timeout in whole seconds to wait for password input
if true, stop processing when entry is matched, defaults to false
require a reason for execution/edit. If reason is true then any reason will satisfy. Any string other than true or false will be treated as a regex match. Defaults to false
length of timeout for token authentication in whole seconds (default 600)
log this activity to syslog, defaults to true
assign value to environment key
(type=edit) set the file mode bits on replacement file to octal mode. When set to keep use the existing file mode. If the file is not present, or mode is not declared, then mode falls back to 0600. If there is a file present, then the mode is read and used just prior to file rename
(type=edit) run program after editor exits as the target user, if exit is zero, continue with file replacement. %{NEW} and %{OLD} placeholders expand to new and old edit files

EXAMPLES

To allow all commands, you can use a greedy match (^.*$). You should reduce this to the set of acceptable commands though.

[user_jim_root]
name = jim
target = root
rule = ^.*$

If you wish to permit a user to view another’s command set, then you may do this using type=list (run by default). To list another user, they must match the target regex.

[user_jim_list_root]
name = jim
type = list
target = root

type may also be edit if you wish to permit a file edit with pleaseedit.

[user_jim_edit_hosts]
name = jim
type = edit
target = root
rule = ^/etc/hosts$
editmode = 644

Naming sections should help later when listing permissions.

Below, user mandy may run du without needing a password, but must enter her password for a bash running as root:

[mandy_du]
name = mandy
rule = ^(/usr)?/bin/du .*$
require_pass = false
[mandy_some]
name = mandy
rule = ^(/usr)?/bin/bash$
require_pass = true

The rule regex can include repetitions. To permit running wc to count the lines in the log files (we don’t know how many there are) in /var/log. This sort of regex will allow multiple instances of a () group with +, which is used to define the character class [a-zA-Z0-9-]+, the numeric class and the group near the end of the line. In other words, multiple instances of files in /var/log that may end in common log rotate forms -YYYYMMDD or .N.

This will permit commands such as the following, note how for efficiency find will combine arguments with + into fewer invocations. xargs could have been used in place of find.

$ find /var/log -type f -exec please /usr/bin/wc {} \+

Here is a sample for the above scenario:

[user_jim_root_wc]
name = jim
target = root
permit = true
rule = ^/usr/bin/wc (/var/log/[a-zA-Z0-9-]+(\.\d+)?(\s)?)+$

User jim may only start or stop a docker container:

[user_jim_root_docker]
name = jim
target = root
permit = true
rule = ^/usr/bin/docker (start|stop) \S+

User ben may only edit /etc/fstab, and afterwards check the fstab file:

[ben_fstab]
name = ben
target = root
permit = true
type = edit
editmode = 644
rule = ^/etc/fstab$
exitcmd = /bin/findmnt --verify --tab-file %{NEW}

User ben may list only users eng, net and dba:

[ben_ops]
name = ben
permit = true
type = list
target = ^(eng|net|dba)ops$

All users may list their own permissions. You may or may not wish to do this if you consider permitting a view of the rules to be a security risk.

[list_own]
name = ^%{USER}$
permit = true
type = list
target = ^%{USER}$

DEFAULT SECTION

Sections that are named starting with default retain their actions, which can be useful for turning off syslog or setting a token_timeout globally, for example, but they will retain permit which implicitly is true, it is therefore sensible to negate this (setting permit=false) and set permit=true in subsequent sections as needed.

[default:nosyslog]
name = .*
rule = .*
require_pass = false
syslog = false
permit = false
token_timeout = 1800
[mailusers]
name = mailadm
group = true
rule = ^/usr/sbin/postcat$
require_pass = true
permit = true

EXITCMD

When the user completes their edit, and the editor exits cleanly, if exitcmd is included then this program will run as the target user. If the program also exits cleanly then the temporary edit will be copied to the destination.

%{OLD} and %{NEW} will expand to the old (existing source) file and edit candidate, respectively. To verify a file edit, ben’s entry to check /etc/hosts after clean exit could look like this:

[ben_ops]
name = ben
permit = true
type = edit
editmode = 644
rule = ^/etc/hosts$
exitcmd = /usr/local/bin/check_hosts %{OLD} %{NEW}

/usr/local/bin/check_hosts takes two arguments, the original file as the first argument and the modify candidate as the second argument. If check_hosts terminates zero, then the edit is considered clean and the original file is replaced with the candidate. Otherwise the edit file is not copied and is left, pleaseedit will exit with the return value from check_hosts.

A common exitcmd is to check the validity of please.ini, shown below. This permits members of the admin group to edit /etc/please.ini if they provide a reason (-r). Upon clean exit from the editor the tmp file will be syntax checked.

[please_ini]
name = admins
group = true
reason = true
rule = /etc/please.ini
type = edit
editmode = 600
exitcmd = /usr/bin/please -c %{NEW}

DATED RANGES

For large environments it is not unusual for a third party to require access during a short time frame for debugging. To accommodate this there are the notbefore and notafter time brackets. These can be either YYYYmmdd or YYYYmmddHHMMSS.

The whole day is considered when using the shorter date form of YYYYmmdd.

Many enterprises may wish to permit periods of access to a user for a limited time only, even if that individual is considered to have a permanent role.

User joker can do what they want as root on 1st April 2021:

[joker_april_first]
name = joker
target = root
permit = true
notbefore = 20210401
notafter = 20210401
rule = ^/bin/bash

DATEMATCHES

datematch matches against the date string Day dd mon HH:MM:SS UTC Year. This enables calendar style date matches.

Note that the day of the month (dd) will be padded with spaces if less than two characters wide.

You can permit a group of users to run /usr/local/housekeeping/ scripts every Monday:

[l2_housekeeping]
name = l2users
group = true
target = root
permit = true
rule = /usr/local/housekeeping/tidy_(logs|images|mail)
datematch = ^Mon\s+.*

REASONS

When reason=true, a user must pass a reason with the -r option to please and pleaseedit. Some organisations may prefer a reason to be logged when a command is executed. This can be helpful for some situations where something such as mkfs or useradd might be preferable to be logged against a ticket.

[l2_user_admin]
name = l2users
group = true
target = root
permit = true
reason = true
rule = ^/usr/sbin/useradd -m \w+$

Or, if tickets have a known prefix:

reason = .*(bug|incident|ticket|change)\d+.*

Perhaps you want to add a mini molly-guard where the hostname must appear in the reason:

[user_poweroff]
name = l2users
group = true
rule = (/usr)?/s?bin/(shutdown( -h now)?|poweroff|reboot)
require_pass = true
reason = .*%{HOSTNAME}.*

DIR

In some situations you may only want a command to run within a set of directories. The directory is specified with the -d argument to please. For example, a program may output to the current working directory, which may only be desirable in certain locations.

[eng_build_aliases]
name = l2users
group = true
dir = ^/etc/mail$
rule = ^/usr/local/bin/build_aliases$

LAST

last = true stops processing at a match:

[mkfs]
name = l2users
group = true
target = root
permit = true
reason = true
rule = ^/sbin/mkfs.(ext[234]|xfs) /dev/sd[bcdefg]\d?$
last = true

For simplicity, there is no need to process other configured rules if certain that the l2users group are safe to execute this. last should only be used in situations where there will never be something that could contradict the match in an undesired way later.

SYSLOG

By default entries are logged to syslog. If you do not wish an entry to be logged then specify syslog=false. In this case jim can run anything in /usr/bin/ as root and it will not be logged.

[maverick]
syslog = false
name = jim
rule = /usr/bin/.*
reason = false

FILES

/etc/please.ini

NOTES

At a later date repeated properties within the same section may be treated as a match list.

CONTRIBUTIONS

I welcome pull requests with open arms. New features always considered.

BUGS

Found a bug? Please either open a ticket or send a pull request/patch.

SEE ALSO

please(1)

AUTHORS

Ed Neville (ed-please@s5h.net).

17 April 2023 please 0.5.4