Functional Programming with Bash - bash

How would I implement something similar to functional programming within bash?
I have a function:
requestPassword(){
passwordValidated=false
while [ "$passwordValidated" = "false" ];do
tput clear
[ -n "$infomsg" ] && echo -e "$infomsg" >&2
[ -n "$errmsg" ] && echo -e "$errmsg" >&2
read -s -p "some prompt:" pass >&2
errmsg=$()#do some validation
[ -n "$errmsg" ] && continue
passwordValidated=true
done
echo "$pass"
}
But I want to make it as generic as possible to work with different systems
Maybe I want to ask the password for an encrypted file
Maybe I want to ask the password for a system user
Maybe I want to use this function to request a new password from a user
The idea would be that I could pass this function a function that takes in a pass parameter and only outputs something if validation failed

You can pass a function name as an argument
requestPassword(){
local infomsg="$1"
local validator=${2:-the_default_validator_function}
# ...
local errmsg
errmsg=$( "$validator" "$pass" )
# ...
}
then
# a valid "foobar" password contains the substring "foo"
foobarPasswordValidator() { [[ $1 == *foo* ]]; }
pass=$(requestPassword "Enter your FooBar password" foobarPasswordValidator)
If you don't have a default validator, use : or true -- they accept arguments, ignore them(1) and return a "success" exit status.
(1) ignored after any parameter expansions have occurred

This is my solution. Please feel free to add any more insight you may have on this topic
requestPassword(){
infomsg="$1"
passwordValidated=false
while [ "$passwordValidated" = "false" ];do
tput clear
[ -n "$infomsg" ] && echo -e "$infomsg" >&2
[ -n "$errmsg" ] && echo -e "$errmsg" >&2
read -s -p "some prompt:" pass >&2
errmsg=$(dynPasswordValidation "$pass")
[ -n "$errmsg" ] && continue
passwordValidated=true
done
echo "$pass"
}
You would then have other functions that would call this function for specific password requests but would define dynPasswordValidation function prior to the call like so:
requestCurrentEncryptedFilePassword(){
infomsg="Requesting password for encrypted file"
dynPasswordValidation(){
[ -n "$(openssl $encalg -d -in $encfile -pass "pass:$1" 2>&1>/dev/null)" ] && echo "Looks like that password didn't work" && return
}
pass="$(requestPassword "$infomsg")"
}
requestNewEncryptedFilePassword(){
infomsg="Requesting new password for encrypted file"
dynPasswordValidation(){
pass="$1"
echo >&2
read -p -s "veri prompt" pass_veri >&2
echo >&2
[ "$pass" != "$pass_veri" ] && echo "Looks like the passwords didn't match" && return
[ -n "$(#run the password through a set of password rules)" ] && echo "Looks like the password is not up to snuff..." && return
}
pass="$(requestPassword "$infomsg")"
}

Related

bash scripting one line shortcut for if test

Is there a shortcut (ie all on one line) for doing the following?
if [ -z "$PASSWORD" ] ; then
echo "PASSWORD envvar required. Exiting..."
exit 1
fi
I'm thinking along the lines of the following. Or maybe there's an even shorter way.
[ -z "$PASSWORD" ] && ...
That is, how do put the echo then exit after the &&
You can do it like this:
[ -z "$PASSWORD" ] && { echo "PASSWORD envvar required. Exiting..."; exit 1; }
Note the extra ; at the end of the line before the }, this is necessary and you cannot leave it out.
It's called a command group.
[[ -z "$PASSWORD" ]] && echo "PASSWORD envvar required. Exiting." && exit 1
Your single brackets will work fine. Consider learning to use the doubles, though.

how can I loop with an error message?

Latest Version
#!/bin/bash
set -e
shopt -s nocasematch
#vars
redbgbold='\e[1;97;41m'
resetcolor='\e[0m'
RegExFQDN='(?=^.{4,253}$)(^((?!-)[a-zA-Z0-9-]{1,63}(?<!-)\.)+[a-zA-Z]{2,63}$)'
#functions
ask() {
local input
until
read -rp "$1 > " input >&2 || return 1
grep -q -P "$2" <<< "$input"
do
printf "ERROR - "${redbgbold}"\"$input\""${resetcolor}" is not a valid " >&2; sed "s/.*the //" <<< "$1" >&2
done
printf '%s\n' "$input"
}
#code
while [ -z $fqdn ]; do
fqdn=$(ask "Enter the FQDN" $RegExFQDN)
echo "FQDN is $fqdn"
done
The Question
I have a read line, and I want to take what the user entered and see if it matches my regex, if it matches we leave the loop, if it fails it prints an error and we do the loop again until we get a match. It looks redundant to me, and I assume there should be a better way but not sure what that should be.
Original Code
#!/bin/bash
set -e
shopt -s nocasematch
function RegexValidation() {
if [ "$2" = "fqdn" ]; then
if [ `echo $1 | grep -c -P '(?=^.{1,254}$)(^(?>(?!\d+\.)[a-z0-9_\-]{1,63}\.?)+(?:[a-z]{2,})$)'` == "0" ]; then
echo "ERROR - $1 is not a valid FQDN"
unset $!{1}
fi
fi
}
while [ -z $fqdn ]; do
read -e -r -p "Enter the Fully Qualified Domain Name > " fqdn
RegexValidation $fqdn fqdn
done
shopt -u nocasematch
any help is appreciated.
Update #1 - fixed formatting issues.
Update #2 - using that other guy's suggestions with a few additional tweaks
I would do basically the same thing, but split it differently to make it easier to reuse:
#!/bin/bash
set -e
ask() {
local input
until
read -rp "$1 > " input >&2 || return 1
grep -q -P "$2" <<< "$input"
do
echo "Invalid answer. Try again" >&2
done
printf '%s\n' "$input"
}
ask_fqdn() {
ask "$1" '(?=^.{1,254}$)(^(?>(?!\d+\.)[a-z0-9_\-]{1,63}\.?)+(?:[a-z]{2,})$)'
}
fqdn=$(ask_fqdn "Enter first FQDN")
echo "You wrote $fqdn"
fqdn=$(ask_fqdn "Enter second FQDN")
echo "This time it was $fqdn"
number=$(ask "And now a number because why not" '^\d+$')
echo "So $number"
Now you don't have to write a new loop every time you want new information, and you can easily ask for new things without modifying the existing functions.
Have the function return a status, which you can test with if in the loop.
And rather than use test to check the result of grep, just test it directly with if. grep returns a non-zero status if the input doesn't match.
function RegexValidation() {
if [ "$2" = "fqdn" ]; then
if ! echo "$1" | grep -q -P '(?=^.{1,254}$)(^(?>(?!\d+\.)[a-z0-9_\-]{1,63}\.?)+(?:[a-z]{2,})$)'; then
echo "ERROR - $1 is not a valid FQDN"
return 1
fi
return 0
fi
}
while :; do
read -e -r -p "Enter the Fully Qualified Domain Name > " fqdn
if RegexValidation "$fqdn" fqdn
then break
fi
done
Also, remember to quote your variables.

Prompt to continue if no argument passed

I want to prompt to do something or not. And if a specific argument such as "-y" or "--yes" is passed I want to make the script non-interactive (force user answer).
if [ $# = 1 ] && [ "$1" = "-y" ]; then
# my code here
else
read -n 1 -p "¿Install this? [y/N] "
if [[ $REPLY =~ ^([Yy])$ ]]; then
# same code here
fi
fi
If I had to use a function I would like it to be something not to do with the code but with the test as I have a lot of this tests in the script.
function(argument)
{
if [ $# = 1 ] && [ "$1" = "-y" ]; then
return true
else
read -n 1 -p "$argument [y/N] "
if [[ $REPLY =~ ^([Yy])$ ]]; then
return true
fi
fi
}
if function("¿Install this?"); then
# my code here
fi
This function is wrong because it overrides the script's argument with the function call's argument.
install_maybe () {
echo $# $1
if [ $# = 1 ] && [ "$1" = "-y" ]; then
return 0
else
read -n 1 -p "$1 [y/N] "
if [[ $REPLY =~ ^[Yy]$ ]]; then
return 0
fi
fi
return 1
}
if install_maybe "Install everything?"; then
source "$DOTFILES/install/esential" "-y"
else source "$DOTFILES/install/esential"
fi
Simply define a flag in a variable that indicates the presence / absence of -y, the auto-confirmation option, among the command-line arguments, and pass that flag to your helper function as a 2nd argument:
#!/bin/bash
# Helper function to ensure that the user has confirmed the intent to proceed.
assertConfirmation() {
local promptMsg=$1 autoConfirm=$2
if (( autoConfirm )); then
return
else
read -n 1 -p "$promptMsg [y/N] "
printf '\n' # Output a newline, because none was appended to the user's keypress.
if [[ $REPLY =~ ^([Yy])$ ]]; then
return
fi
fi
# Getting here means: confirmation was not given - abort the script as a whole.
echo "Aborted." >&2 # Note how the message is sent to *stderr*.
exit 2 # Use a dedicated exit code to signal this condition.
}
# ... Code that performs proper parsing of command-line arguments,
# such as with getopts or GNU getopt, omitted for brevity.
# Here, I assume that the option to signal automatic confirmation
# is in $1, if provided.
[[ $1 == '-y' ]] && autoConfirm=1 || autoConfirm=0
# Call the helper function, which only returns if confirmation is
# either implied by the relevant command-line option or, in its absence,
# by the user confirming the intent to proceed interactively.
assertConfirmation "Install everything?" "$autoConfirm"
# Proceed...
echo "Installing..."

Bash, always echo in conditional statement

This may turn out to be more of a thought exercise, but I am trying to echo a newline after some command I'm executing within a conditional. For example, I have:
if ssh me#host [ -e $filename ] ; then
echo "File exists remotely"
else
echo "Does not exist remotely"
fi
And want to throw in an echo after the ssh command regardless of the outcome. The reason is formatting; that way a newline will exist after the prompt for password for ssh.
First Try
if ssh me#host [ -e $filename ] && echo ; then
Because && echo would not change the conditional outcome, but bash would not execute echo if ssh returned false. Similarly,
if ssh me#host [ -e $filename ] || (echo && false) ; then
Does not work because it will short-circuit if ssh returns true.
An answer to the problem would be
ssh me#host [ -e $filename ]
result=$?
echo
if [ $result == 0 ] ; then
but was wondering if there was some similar conditional expression to do this.
Thanks.
While this would work
if foo && echo || ! echo; then
I'd prefer putting the whole thing into a function
function addecho() {
"$#" # execute command passed as arguments (including parameters)
result= $? # store return value
echo
return $result # return stored result
}
if addecho foo; then
What about this?
if ssh me#host [ -e $filename ] && echo || echo; then
I have not thought about precedence order of && and || and surely putting some parenthesis would help, but like that it works already... you get the echo both when ssh fails and when it succeeds...
Add the "echo" before the filename test
if ssh me#host "echo; [ -e $filename ]"; then
echo "File exists remotely"
else
echo "Does not exist remotely"
fi

How to get a password from a shell script without echoing

I have a script that automates a process that needs access to a password protected system. The system is accessed via a command-line program that accepts the user password as an argument.
I would like to prompt the user to type in their password, assign it to a shell variable, and then use that variable to construct the command line of the accessing program (which will of course produce stream output that I will process).
I am a reasonably competent shell programmer in Bourne/Bash, but I don't know how to accept the user input without having it echo to the terminal (or maybe having it echoed using '*' characters).
Can anyone help with this?
Here is another way to do it:
#!/bin/bash
# Read Password
echo -n Password:
read -s password
echo
# Run Command
echo $password
The read -s will turn off echo for you. Just replace the echo on the last line with the command you want to run.
In some shells (e.g. bash) read supports -p prompt-string which will allow the echo and read commands to be combined.
read -s -p "Password: " password
A POSIX compliant answer. Notice the use of /bin/sh instead of /bin/bash. (It does work with bash, but it does not require bash.)
#!/bin/sh
stty -echo
printf "Password: "
read PASSWORD
stty echo
printf "\n"
One liner:
read -s -p "Password: " password
Under Linux (and cygwin) this form works in bash and sh. It may not be standard Unix sh, though.
For more info and options, in bash, type "help read".
$ help read
read: read [-ers] [-a array] [-d delim] [-i text] [-n nchars] [-N nchars] [-p prompt] [-t timeout] [-u fd] [name ...]
Read a line from the standard input and split it into fields.
...
-p prompt output the string PROMPT without a trailing newline before
attempting to read
...
-s do not echo input coming from a terminal
The -s option of read is not defined in the POSIX standard. See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/read.html. I wanted something that would work for any POSIX shell, so I wrote a little function that uses stty to disable echo.
#!/bin/sh
# Read secret string
read_secret()
{
# Disable echo.
stty -echo
# Set up trap to ensure echo is enabled before exiting if the script
# is terminated while echo is disabled.
trap 'stty echo' EXIT
# Read secret.
read "$#"
# Enable echo.
stty echo
trap - EXIT
# Print a newline because the newline entered by the user after
# entering the passcode is not echoed. This ensures that the
# next line of output begins at a new line.
echo
}
This function behaves quite similar to the read command. Here is a simple usage of read followed by similar usage of read_secret. The input to read_secret appears empty because it was not echoed to the terminal.
[susam#cube ~]$ read a b c
foo \bar baz \qux
[susam#cube ~]$ echo a=$a b=$b c=$c
a=foo b=bar c=baz qux
[susam#cube ~]$ unset a b c
[susam#cube ~]$ read_secret a b c
[susam#cube ~]$ echo a=$a b=$b c=$c
a=foo b=bar c=baz qux
[susam#cube ~]$ unset a b c
Here is another that uses the -r option to preserve the backslashes in the input. This works because the read_secret function defined above passes all arguments it receives to the read command.
[susam#cube ~]$ read -r a b c
foo \bar baz \qux
[susam#cube ~]$ echo a=$a b=$b c=$c
a=foo b=\bar c=baz \qux
[susam#cube ~]$ unset a b c
[susam#cube ~]$ read_secret -r a b c
[susam#cube ~]$ echo a=$a b=$b c=$c
a=foo b=\bar c=baz \qux
[susam#cube ~]$ unset a b c
Finally, here is an example that shows how to use the read_secret function to read a password in a POSIX compliant manner.
printf "Password: "
read_secret password
# Do something with $password here ...
I found to be the the askpass command useful
password=$(/lib/cryptsetup/askpass "Give a password")
Every input character is replaced by *. See:
Give a password ****
You can also prompt for a password without setting a variable in the current shell by doing something like this:
$(read -s;echo $REPLY)
For instance:
my-command --set password=$(read -sp "Password: ";echo $REPLY)
You can add several of these prompted values with line break, doing this:
my-command --set user=$(read -sp "`echo $'\n '`User: ";echo $REPLY) --set password=$(read -sp "`echo $'\n '`Password: ";echo $REPLY)
Turn echo off using stty, then back on again after.
While there are plenty of answers already, there is one more way to ask for passwords from terminal in virtually any modern linux that runs systemd (yes, booo, I know, but what can you do about it). systemd-ask-password command is included with standard core systemd package and can be used like this:
#!/bin/sh
PASSWORD="$(systemd-ask-password "Enter your password:")"
Use --emoji=no switch to suppress that stupid unicode lock character. It works great inside terminal but requires tweaking if you need it to pop up a GUI dialog, but that is out of scope here.
This link is help in defining,
* How to read password from use without echo-ing it back to terminal
* How to replace each character with * -character.
https://www.tutorialkart.com/bash-shell-scripting/bash-read-username-and-password/
For anyone needing to prompt for a password, you may be interested in using encpass.sh. This is a script I wrote for similar purposes of capturing a secret at runtime and then encrypting it for subsequent occasions. Subsequent runs do not prompt for the password as it will just use the encrypted value from disk.
It stores the encrypted passwords in a hidden folder under the user's home directory or in a custom folder that you can define through the environment variable ENCPASS_HOME_DIR. It is designed to be POSIX compliant and has an MIT License, so it can be used even in corporate enterprise environments. My company, Plyint LLC, maintains the script and occasionally releases updates. Pull requests are also welcome, if you find an issue. :)
To use it in your scripts simply source encpass.sh in your script and call the get_secret function. I'm including a copy of the script below for easy visibility.
#!/bin/sh
################################################################################
# Copyright (c) 2020 Plyint, LLC <contact#plyint.com>. All Rights Reserved.
# This file is licensed under the MIT License (MIT).
# Please see LICENSE.txt for more information.
#
# DESCRIPTION:
# This script allows a user to encrypt a password (or any other secret) at
# runtime and then use it, decrypted, within a script. This prevents shoulder
# surfing passwords and avoids storing the password in plain text, which could
# inadvertently be sent to or discovered by an individual at a later date.
#
# This script generates an AES 256 bit symmetric key for each script (or user-
# defined bucket) that stores secrets. This key will then be used to encrypt
# all secrets for that script or bucket. encpass.sh sets up a directory
# (.encpass) under the user's home directory where keys and secrets will be
# stored.
#
# For further details, see README.md or run "./encpass ?" from the command line.
#
################################################################################
encpass_checks() {
if [ -n "$ENCPASS_CHECKS" ]; then
return
fi
if [ ! -x "$(command -v openssl)" ]; then
echo "Error: OpenSSL is not installed or not accessible in the current path." \
"Please install it and try again." >&2
exit 1
fi
if [ -z "$ENCPASS_HOME_DIR" ]; then
ENCPASS_HOME_DIR=$(encpass_get_abs_filename ~)/.encpass
fi
if [ ! -d "$ENCPASS_HOME_DIR" ]; then
mkdir -m 700 "$ENCPASS_HOME_DIR"
mkdir -m 700 "$ENCPASS_HOME_DIR/keys"
mkdir -m 700 "$ENCPASS_HOME_DIR/secrets"
fi
if [ "$(basename "$0")" != "encpass.sh" ]; then
encpass_include_init "$1" "$2"
fi
ENCPASS_CHECKS=1
}
# Initializations performed when the script is included by another script
encpass_include_init() {
if [ -n "$1" ] && [ -n "$2" ]; then
ENCPASS_BUCKET=$1
ENCPASS_SECRET_NAME=$2
elif [ -n "$1" ]; then
ENCPASS_BUCKET=$(basename "$0")
ENCPASS_SECRET_NAME=$1
else
ENCPASS_BUCKET=$(basename "$0")
ENCPASS_SECRET_NAME="password"
fi
}
encpass_generate_private_key() {
ENCPASS_KEY_DIR="$ENCPASS_HOME_DIR/keys/$ENCPASS_BUCKET"
if [ ! -d "$ENCPASS_KEY_DIR" ]; then
mkdir -m 700 "$ENCPASS_KEY_DIR"
fi
if [ ! -f "$ENCPASS_KEY_DIR/private.key" ]; then
(umask 0377 && printf "%s" "$(openssl rand -hex 32)" >"$ENCPASS_KEY_DIR/private.key")
fi
}
encpass_get_private_key_abs_name() {
ENCPASS_PRIVATE_KEY_ABS_NAME="$ENCPASS_HOME_DIR/keys/$ENCPASS_BUCKET/private.key"
if [ "$1" != "nogenerate" ]; then
if [ ! -f "$ENCPASS_PRIVATE_KEY_ABS_NAME" ]; then
encpass_generate_private_key
fi
fi
}
encpass_get_secret_abs_name() {
ENCPASS_SECRET_ABS_NAME="$ENCPASS_HOME_DIR/secrets/$ENCPASS_BUCKET/$ENCPASS_SECRET_NAME.enc"
if [ "$3" != "nocreate" ]; then
if [ ! -f "$ENCPASS_SECRET_ABS_NAME" ]; then
set_secret "$1" "$2"
fi
fi
}
get_secret() {
encpass_checks "$1" "$2"
encpass_get_private_key_abs_name
encpass_get_secret_abs_name "$1" "$2"
encpass_decrypt_secret
}
set_secret() {
encpass_checks "$1" "$2"
if [ "$3" != "reuse" ] || { [ -z "$ENCPASS_SECRET_INPUT" ] && [ -z "$ENCPASS_CSECRET_INPUT" ]; }; then
echo "Enter $ENCPASS_SECRET_NAME:" >&2
stty -echo
read -r ENCPASS_SECRET_INPUT
stty echo
echo "Confirm $ENCPASS_SECRET_NAME:" >&2
stty -echo
read -r ENCPASS_CSECRET_INPUT
stty echo
fi
if [ "$ENCPASS_SECRET_INPUT" = "$ENCPASS_CSECRET_INPUT" ]; then
encpass_get_private_key_abs_name
ENCPASS_SECRET_DIR="$ENCPASS_HOME_DIR/secrets/$ENCPASS_BUCKET"
if [ ! -d "$ENCPASS_SECRET_DIR" ]; then
mkdir -m 700 "$ENCPASS_SECRET_DIR"
fi
printf "%s" "$(openssl rand -hex 16)" >"$ENCPASS_SECRET_DIR/$ENCPASS_SECRET_NAME.enc"
ENCPASS_OPENSSL_IV="$(cat "$ENCPASS_SECRET_DIR/$ENCPASS_SECRET_NAME.enc")"
echo "$ENCPASS_SECRET_INPUT" | openssl enc -aes-256-cbc -e -a -iv \
"$ENCPASS_OPENSSL_IV" -K \
"$(cat "$ENCPASS_HOME_DIR/keys/$ENCPASS_BUCKET/private.key")" 1>> \
"$ENCPASS_SECRET_DIR/$ENCPASS_SECRET_NAME.enc"
else
echo "Error: secrets do not match. Please try again." >&2
exit 1
fi
}
encpass_get_abs_filename() {
# $1 : relative filename
filename="$1"
parentdir="$(dirname "${filename}")"
if [ -d "${filename}" ]; then
cd "${filename}" && pwd
elif [ -d "${parentdir}" ]; then
echo "$(cd "${parentdir}" && pwd)/$(basename "${filename}")"
fi
}
encpass_decrypt_secret() {
if [ -f "$ENCPASS_PRIVATE_KEY_ABS_NAME" ]; then
ENCPASS_DECRYPT_RESULT="$(dd if="$ENCPASS_SECRET_ABS_NAME" ibs=1 skip=32 2> /dev/null | openssl enc -aes-256-cbc \
-d -a -iv "$(head -c 32 "$ENCPASS_SECRET_ABS_NAME")" -K "$(cat "$ENCPASS_PRIVATE_KEY_ABS_NAME")" 2> /dev/null)"
if [ ! -z "$ENCPASS_DECRYPT_RESULT" ]; then
echo "$ENCPASS_DECRYPT_RESULT"
else
# If a failed unlock command occurred and the user tries to show the secret
# Present either locked or decrypt command
if [ -f "$ENCPASS_HOME_DIR/keys/$ENCPASS_BUCKET/private.lock" ]; then
echo "**Locked**"
else
# The locked file wasn't present as expected. Let's display a failure
echo "Error: Failed to decrypt"
fi
fi
elif [ -f "$ENCPASS_HOME_DIR/keys/$ENCPASS_BUCKET/private.lock" ]; then
echo "**Locked**"
else
echo "Error: Unable to decrypt. The key file \"$ENCPASS_PRIVATE_KEY_ABS_NAME\" is not present."
fi
}
##########################################################
# COMMAND LINE MANAGEMENT SUPPORT
# -------------------------------
# If you don't need to manage the secrets for the scripts
# with encpass.sh you can delete all code below this point
# in order to significantly reduce the size of encpass.sh.
# This is useful if you want to bundle encpass.sh with
# your existing scripts and just need the retrieval
# functions.
##########################################################
encpass_show_secret() {
encpass_checks
ENCPASS_BUCKET=$1
encpass_get_private_key_abs_name "nogenerate"
if [ ! -z "$2" ]; then
ENCPASS_SECRET_NAME=$2
encpass_get_secret_abs_name "$1" "$2" "nocreate"
if [ -z "$ENCPASS_SECRET_ABS_NAME" ]; then
echo "No secret named $2 found for bucket $1."
exit 1
fi
encpass_decrypt_secret
else
ENCPASS_FILE_LIST=$(ls -1 "$ENCPASS_HOME_DIR"/secrets/"$1")
for ENCPASS_F in $ENCPASS_FILE_LIST; do
ENCPASS_SECRET_NAME=$(basename "$ENCPASS_F" .enc)
encpass_get_secret_abs_name "$1" "$ENCPASS_SECRET_NAME" "nocreate"
if [ -z "$ENCPASS_SECRET_ABS_NAME" ]; then
echo "No secret named $ENCPASS_SECRET_NAME found for bucket $1."
exit 1
fi
echo "$ENCPASS_SECRET_NAME = $(encpass_decrypt_secret)"
done
fi
}
encpass_getche() {
old=$(stty -g)
stty raw min 1 time 0
printf '%s' "$(dd bs=1 count=1 2>/dev/null)"
stty "$old"
}
encpass_remove() {
if [ ! -n "$ENCPASS_FORCE_REMOVE" ]; then
if [ ! -z "$ENCPASS_SECRET" ]; then
printf "Are you sure you want to remove the secret \"%s\" from bucket \"%s\"? [y/N]" "$ENCPASS_SECRET" "$ENCPASS_BUCKET"
else
printf "Are you sure you want to remove the bucket \"%s?\" [y/N]" "$ENCPASS_BUCKET"
fi
ENCPASS_CONFIRM="$(encpass_getche)"
printf "\n"
if [ "$ENCPASS_CONFIRM" != "Y" ] && [ "$ENCPASS_CONFIRM" != "y" ]; then
exit 0
fi
fi
if [ ! -z "$ENCPASS_SECRET" ]; then
rm -f "$1"
printf "Secret \"%s\" removed from bucket \"%s\".\n" "$ENCPASS_SECRET" "$ENCPASS_BUCKET"
else
rm -Rf "$ENCPASS_HOME_DIR/keys/$ENCPASS_BUCKET"
rm -Rf "$ENCPASS_HOME_DIR/secrets/$ENCPASS_BUCKET"
printf "Bucket \"%s\" removed.\n" "$ENCPASS_BUCKET"
fi
}
encpass_save_err() {
if read -r x; then
{ printf "%s\n" "$x"; cat; } > "$1"
elif [ "$x" != "" ]; then
printf "%s" "$x" > "$1"
fi
}
encpass_help() {
less << EOF
NAME:
encpass.sh - Use encrypted passwords in shell scripts
DESCRIPTION:
A lightweight solution for using encrypted passwords in shell scripts
using OpenSSL. It allows a user to encrypt a password (or any other secret)
at runtime and then use it, decrypted, within a script. This prevents
shoulder surfing passwords and avoids storing the password in plain text,
within a script, which could inadvertently be sent to or discovered by an
individual at a later date.
This script generates an AES 256 bit symmetric key for each script
(or user-defined bucket) that stores secrets. This key will then be used
to encrypt all secrets for that script or bucket.
Subsequent calls to retrieve a secret will not prompt for a secret to be
entered as the file with the encrypted value already exists.
Note: By default, encpass.sh sets up a directory (.encpass) under the
user's home directory where keys and secrets will be stored. This directory
can be overridden by setting the environment variable ENCPASS_HOME_DIR to a
directory of your choice.
~/.encpass (or the directory specified by ENCPASS_HOME_DIR) will contain
the following subdirectories:
- keys (Holds the private key for each script/bucket)
- secrets (Holds the secrets stored for each script/bucket)
USAGE:
To use the encpass.sh script in an existing shell script, source the script
and then call the get_secret function.
Example:
#!/bin/sh
. encpass.sh
password=\$(get_secret)
When no arguments are passed to the get_secret function,
then the bucket name is set to the name of the script and
the secret name is set to "password".
There are 2 other ways to call get_secret:
Specify the secret name:
Ex: \$(get_secret user)
- bucket name = <script name>
- secret name = "user"
Specify both the secret name and bucket name:
Ex: \$(get_secret personal user)
- bucket name = "personal"
- secret name = "user"
encpass.sh also provides a command line interface to manage the secrets.
To invoke a command, pass it as an argument to encpass.sh from the shell.
$ encpass.sh [COMMAND]
See the COMMANDS section below for a list of available commands. Wildcard
handling is implemented for secret and bucket names. This enables
performing operations like adding/removing a secret to/from multiple buckets
at once.
COMMANDS:
add [-f] <bucket> <secret>
Add a secret to the specified bucket. The bucket will be created
if it does not already exist. If a secret with the same name already
exists for the specified bucket, then the user will be prompted to
confirm overwriting the value. If the -f option is passed, then the
add operation will perform a forceful overwrite of the value. (i.e. no
prompt)
list|ls [<bucket>]
Display the names of the secrets held in the bucket. If no bucket
is specified, then the names of all existing buckets will be
displayed.
lock
Locks all keys used by encpass.sh using a password. The user
will be prompted to enter a password and confirm it. A user
should take care to securely store the password. If the password
is lost then keys can not be unlocked. When keys are locked,
secrets can not be retrieved. (e.g. the output of the values
in the "show" command will be encrypted/garbage)
remove|rm [-f] <bucket> [<secret>]
Remove a secret from the specified bucket. If only a bucket is
specified then the entire bucket (i.e. all secrets and keys) will
be removed. By default the user is asked to confirm the removal of
the secret or the bucket. If the -f option is passed then a
forceful removal will be performed. (i.e. no prompt)
show [<bucket>] [<secret>]
Show the unencrypted value of the secret from the specified bucket.
If no secret is specified then all secrets for the bucket are displayed.
update <bucket> <secret>
Updates a secret in the specified bucket. This command is similar
to using an "add -f" command, but it has a safety check to only
proceed if the specified secret exists. If the secret, does not
already exist, then an error will be reported. There is no forceable
update implemented. Use "add -f" for any required forceable update
scenarios.
unlock
Unlocks all the keys for encpass.sh. The user will be prompted to
enter the password and confirm it.
dir
Prints out the current value of the ENCPASS_HOME_DIR environment variable.
help|--help|usage|--usage|?
Display this help message.
EOF
}
# Subcommands for cli support
case "$1" in
add )
shift
while getopts ":f" ENCPASS_OPTS; do
case "$ENCPASS_OPTS" in
f ) ENCPASS_FORCE_ADD=1;;
esac
done
encpass_checks
if [ -n "$ENCPASS_FORCE_ADD" ]; then
shift $((OPTIND-1))
fi
if [ ! -z "$1" ] && [ ! -z "$2" ]; then
# Allow globbing
# shellcheck disable=SC2027,SC2086
ENCPASS_ADD_LIST="$(ls -1d "$ENCPASS_HOME_DIR/secrets/"$1"" 2>/dev/null)"
if [ -z "$ENCPASS_ADD_LIST" ]; then
ENCPASS_ADD_LIST="$1"
fi
for ENCPASS_ADD_F in $ENCPASS_ADD_LIST; do
ENCPASS_ADD_DIR="$(basename "$ENCPASS_ADD_F")"
ENCPASS_BUCKET="$ENCPASS_ADD_DIR"
if [ ! -n "$ENCPASS_FORCE_ADD" ] && [ -f "$ENCPASS_ADD_F/$2.enc" ]; then
echo "Warning: A secret with the name \"$2\" already exists for bucket $ENCPASS_BUCKET."
echo "Would you like to overwrite the value? [y/N]"
ENCPASS_CONFIRM="$(encpass_getche)"
if [ "$ENCPASS_CONFIRM" != "Y" ] && [ "$ENCPASS_CONFIRM" != "y" ]; then
continue
fi
fi
ENCPASS_SECRET_NAME="$2"
echo "Adding secret \"$ENCPASS_SECRET_NAME\" to bucket \"$ENCPASS_BUCKET\"..."
set_secret "$ENCPASS_BUCKET" "$ENCPASS_SECRET_NAME" "reuse"
done
else
echo "Error: A bucket name and secret name must be provided when adding a secret."
exit 1
fi
;;
update )
shift
encpass_checks
if [ ! -z "$1" ] && [ ! -z "$2" ]; then
ENCPASS_SECRET_NAME="$2"
# Allow globbing
# shellcheck disable=SC2027,SC2086
ENCPASS_UPDATE_LIST="$(ls -1d "$ENCPASS_HOME_DIR/secrets/"$1"" 2>/dev/null)"
for ENCPASS_UPDATE_F in $ENCPASS_UPDATE_LIST; do
# Allow globbing
# shellcheck disable=SC2027,SC2086
if [ -f "$ENCPASS_UPDATE_F/"$2".enc" ]; then
ENCPASS_UPDATE_DIR="$(basename "$ENCPASS_UPDATE_F")"
ENCPASS_BUCKET="$ENCPASS_UPDATE_DIR"
echo "Updating secret \"$ENCPASS_SECRET_NAME\" to bucket \"$ENCPASS_BUCKET\"..."
set_secret "$ENCPASS_BUCKET" "$ENCPASS_SECRET_NAME" "reuse"
else
echo "Error: A secret with the name \"$2\" does not exist for bucket $1."
exit 1
fi
done
else
echo "Error: A bucket name and secret name must be provided when updating a secret."
exit 1
fi
;;
rm|remove )
shift
encpass_checks
while getopts ":f" ENCPASS_OPTS; do
case "$ENCPASS_OPTS" in
f ) ENCPASS_FORCE_REMOVE=1;;
esac
done
if [ -n "$ENCPASS_FORCE_REMOVE" ]; then
shift $((OPTIND-1))
fi
if [ -z "$1" ]; then
echo "Error: A bucket must be specified for removal."
fi
# Allow globbing
# shellcheck disable=SC2027,SC2086
ENCPASS_REMOVE_BKT_LIST="$(ls -1d "$ENCPASS_HOME_DIR/secrets/"$1"" 2>/dev/null)"
if [ ! -z "$ENCPASS_REMOVE_BKT_LIST" ]; then
for ENCPASS_REMOVE_B in $ENCPASS_REMOVE_BKT_LIST; do
ENCPASS_BUCKET="$(basename "$ENCPASS_REMOVE_B")"
if [ ! -z "$2" ]; then
# Removing secrets for a specified bucket
# Allow globbing
# shellcheck disable=SC2027,SC2086
ENCPASS_REMOVE_LIST="$(ls -1p "$ENCPASS_REMOVE_B/"$2".enc" 2>/dev/null)"
if [ -z "$ENCPASS_REMOVE_LIST" ]; then
echo "Error: No secrets found for $2 in bucket $ENCPASS_BUCKET."
exit 1
fi
for ENCPASS_REMOVE_F in $ENCPASS_REMOVE_LIST; do
ENCPASS_SECRET="$2"
encpass_remove "$ENCPASS_REMOVE_F"
done
else
# Removing a specified bucket
encpass_remove
fi
done
else
echo "Error: The bucket named $1 does not exist."
exit 1
fi
;;
show )
shift
encpass_checks
if [ -z "$1" ]; then
ENCPASS_SHOW_DIR="*"
else
ENCPASS_SHOW_DIR=$1
fi
if [ ! -z "$2" ]; then
# Allow globbing
# shellcheck disable=SC2027,SC2086
if [ -f "$(encpass_get_abs_filename "$ENCPASS_HOME_DIR/secrets/$ENCPASS_SHOW_DIR/"$2".enc")" ]; then
encpass_show_secret "$ENCPASS_SHOW_DIR" "$2"
fi
else
# Allow globbing
# shellcheck disable=SC2027,SC2086
ENCPASS_SHOW_LIST="$(ls -1d "$ENCPASS_HOME_DIR/secrets/"$ENCPASS_SHOW_DIR"" 2>/dev/null)"
if [ -z "$ENCPASS_SHOW_LIST" ]; then
if [ "$ENCPASS_SHOW_DIR" = "*" ]; then
echo "Error: No buckets exist."
else
echo "Error: Bucket $1 does not exist."
fi
exit 1
fi
for ENCPASS_SHOW_F in $ENCPASS_SHOW_LIST; do
ENCPASS_SHOW_DIR="$(basename "$ENCPASS_SHOW_F")"
echo "$ENCPASS_SHOW_DIR:"
encpass_show_secret "$ENCPASS_SHOW_DIR"
echo " "
done
fi
;;
ls|list )
shift
encpass_checks
if [ ! -z "$1" ]; then
# Allow globbing
# shellcheck disable=SC2027,SC2086
ENCPASS_FILE_LIST="$(ls -1p "$ENCPASS_HOME_DIR/secrets/"$1"" 2>/dev/null)"
if [ -z "$ENCPASS_FILE_LIST" ]; then
# Allow globbing
# shellcheck disable=SC2027,SC2086
ENCPASS_DIR_EXISTS="$(ls -d "$ENCPASS_HOME_DIR/secrets/"$1"" 2>/dev/null)"
if [ ! -z "$ENCPASS_DIR_EXISTS" ]; then
echo "Bucket $1 is empty."
else
echo "Error: Bucket $1 does not exist."
fi
exit 1
fi
ENCPASS_NL=""
for ENCPASS_F in $ENCPASS_FILE_LIST; do
if [ -d "${ENCPASS_F%:}" ]; then
printf "$ENCPASS_NL%s\n" "$(basename "$ENCPASS_F")"
ENCPASS_NL="\n"
else
printf "%s\n" "$(basename "$ENCPASS_F" .enc)"
fi
done
else
# Allow globbing
# shellcheck disable=SC2027,SC2086
ENCPASS_BUCKET_LIST="$(ls -1p "$ENCPASS_HOME_DIR/secrets/"$1"" 2>/dev/null)"
for ENCPASS_C in $ENCPASS_BUCKET_LIST; do
if [ -d "${ENCPASS_C%:}" ]; then
printf "\n%s" "\n$(basename "$ENCPASS_C")"
else
basename "$ENCPASS_C" .enc
fi
done
fi
;;
lock )
shift
encpass_checks
echo "************************!!!WARNING!!!*************************" >&2
echo "* You are about to lock your keys with a password. *" >&2
echo "* You will not be able to use your secrets again until you *" >&2
echo "* unlock the keys with the same password. It is important *" >&2
echo "* that you securely store the password, so you can recall it *" >&2
echo "* in the future. If you forget your password you will no *" >&2
echo "* longer be able to access your secrets. *" >&2
echo "************************!!!WARNING!!!*************************" >&2
printf "\n%s\n" "About to lock keys held in directory $ENCPASS_HOME_DIR/keys/"
printf "\nEnter Password to lock keys:" >&2
stty -echo
read -r ENCPASS_KEY_PASS
printf "\nConfirm Password:" >&2
read -r ENCPASS_CKEY_PASS
printf "\n"
stty echo
if [ -z "$ENCPASS_KEY_PASS" ]; then
echo "Error: You must supply a password value."
exit 1
fi
if [ "$ENCPASS_KEY_PASS" = "$ENCPASS_CKEY_PASS" ]; then
ENCPASS_NUM_KEYS_LOCKED=0
ENCPASS_KEYS_LIST="$(ls -1d "$ENCPASS_HOME_DIR/keys/"*"/" 2>/dev/null)"
for ENCPASS_KEY_F in $ENCPASS_KEYS_LIST; do
if [ -d "${ENCPASS_KEY_F%:}" ]; then
ENCPASS_KEY_NAME="$(basename "$ENCPASS_KEY_F")"
ENCPASS_KEY_VALUE=""
if [ -f "$ENCPASS_KEY_F/private.key" ]; then
ENCPASS_KEY_VALUE="$(cat "$ENCPASS_KEY_F/private.key")"
if [ ! -f "$ENCPASS_KEY_F/private.lock" ]; then
echo "Locking key $ENCPASS_KEY_NAME..."
else
echo "Error: The key $ENCPASS_KEY_NAME appears to have been previously locked."
echo " The current key file may hold a bad value. Exiting to avoid encrypting"
echo " a bad value and overwriting the lock file."
exit 1
fi
else
echo "Error: Private key file ${ENCPASS_KEY_F}private.key missing for bucket $ENCPASS_KEY_NAME."
exit 1
fi
if [ ! -z "$ENCPASS_KEY_VALUE" ]; then
openssl enc -aes-256-cbc -pbkdf2 -iter 10000 -salt -in "$ENCPASS_KEY_F/private.key" -out "$ENCPASS_KEY_F/private.lock" -k "$ENCPASS_KEY_PASS"
if [ -f "$ENCPASS_KEY_F/private.key" ] && [ -f "$ENCPASS_KEY_F/private.lock" ]; then
# Both the key and lock file exist. We can remove the key file now
rm -f "$ENCPASS_KEY_F/private.key"
echo "Locked key $ENCPASS_KEY_NAME."
ENCPASS_NUM_KEYS_LOCKED=$(( ENCPASS_NUM_KEYS_LOCKED + 1 ))
else
echo "Error: The key fle and/or lock file were not found as expected for key $ENCPASS_KEY_NAME."
fi
else
echo "Error: No key value found for the $ENCPASS_KEY_NAME key."
exit 1
fi
fi
done
echo "Locked $ENCPASS_NUM_KEYS_LOCKED keys."
else
echo "Error: Passwords do not match."
fi
;;
unlock )
shift
encpass_checks
printf "%s\n" "About to unlock keys held in the $ENCPASS_HOME_DIR/keys/ directory."
printf "\nEnter Password to unlock keys: " >&2
stty -echo
read -r ENCPASS_KEY_PASS
printf "\n"
stty echo
if [ ! -z "$ENCPASS_KEY_PASS" ]; then
ENCPASS_NUM_KEYS_UNLOCKED=0
ENCPASS_KEYS_LIST="$(ls -1d "$ENCPASS_HOME_DIR/keys/"*"/" 2>/dev/null)"
for ENCPASS_KEY_F in $ENCPASS_KEYS_LIST; do
if [ -d "${ENCPASS_KEY_F%:}" ]; then
ENCPASS_KEY_NAME="$(basename "$ENCPASS_KEY_F")"
echo "Unlocking key $ENCPASS_KEY_NAME..."
if [ -f "$ENCPASS_KEY_F/private.key" ] && [ ! -f "$ENCPASS_KEY_F/private.lock" ]; then
echo "Error: Key $ENCPASS_KEY_NAME appears to be unlocked already."
exit 1
fi
if [ -f "$ENCPASS_KEY_F/private.lock" ]; then
# Remove the failed file in case previous decryption attempts were unsuccessful
rm -f "$ENCPASS_KEY_F/failed" 2>/dev/null
# Decrypt key. Log any failure to the "failed" file.
openssl enc -aes-256-cbc -d -pbkdf2 -iter 10000 -salt \
-in "$ENCPASS_KEY_F/private.lock" -out "$ENCPASS_KEY_F/private.key" \
-k "$ENCPASS_KEY_PASS" 2>&1 | encpass_save_err "$ENCPASS_KEY_F/failed"
if [ ! -f "$ENCPASS_KEY_F/failed" ]; then
# No failure has occurred.
if [ -f "$ENCPASS_KEY_F/private.key" ] && [ -f "$ENCPASS_KEY_F/private.lock" ]; then
# Both the key and lock file exist. We can remove the lock file now.
rm -f "$ENCPASS_KEY_F/private.lock"
echo "Unlocked key $ENCPASS_KEY_NAME."
ENCPASS_NUM_KEYS_UNLOCKED=$(( ENCPASS_NUM_KEYS_UNLOCKED + 1 ))
else
echo "Error: The key file and/or lock file were not found as expected for key $ENCPASS_KEY_NAME."
fi
else
printf "Error: Failed to unlock key %s.\n" "$ENCPASS_KEY_NAME"
printf " Please view %sfailed for details.\n" "$ENCPASS_KEY_F"
fi
else
echo "Error: No lock file found for the $ENCPASS_KEY_NAME key."
fi
fi
done
echo "Unlocked $ENCPASS_NUM_KEYS_UNLOCKED keys."
else
echo "No password entered."
fi
;;
dir )
shift
encpass_checks
echo "ENCPASS_HOME_DIR=$ENCPASS_HOME_DIR"
;;
help|--help|usage|--usage|\? )
encpass_checks
encpass_help
;;
* )
if [ ! -z "$1" ]; then
echo "Command not recognized. See \"encpass.sh help\" for a list commands."
exit 1
fi
;;
esac

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