my dotz
add pa
author
j3s
date
(Jan 22, 2021, 11:58 PM -0600)
commit
630f1a4b
630f1a4b850fb91962f53221d66d7079a34c8aea
parent
336b9a0a
336b9a0a02c2d4faba962f670ade1fbbcc6f9103
+204
+204
bin/pa
+204
bin/pa
···
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#!/bin/sh
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#
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# pa - simple password manager based on age
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pw_add() {
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name=$1
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if yn "Generate a password?"; then
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# Generate a password by reading '/dev/urandom' with the
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# 'tr' command to translate the random bytes into a
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# configurable character set.
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#
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# The 'dd' command is then used to read only the desired
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# password length.
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#
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# Regarding usage of '/dev/urandom' instead of '/dev/random'.
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# See: https://www.2uo.de/myths-about-urandom
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pass=$(LC_ALL=C tr -dc "${PA_PATTERN:-_A-Z-a-z-0-9}" < /dev/urandom |
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dd ibs=1 obs=1 count="${PA_LENGTH:-50}" 2>/dev/null)
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else
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# 'sread()' is a simple wrapper function around 'read'
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# to prevent user input from being printed to the terminal.
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sread pass "Enter password"
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sread pass2 "Enter password (again)"
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# Disable this check as we dynamically populate the two
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# passwords using the 'sread()' function.
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# shellcheck disable=2154
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[ "$pass" = "$pass2" ] || die "Passwords do not match"
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fi
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[ "$pass" ] || die "Failed to generate a password"
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# Mimic the use of an array for storing arguments by... using
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# the function's argument list. This is very apt isn't it?
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set -- -c
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# Use 'age' to store the password in an encrypted file.
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# A heredoc is used here instead of a 'printf' to avoid
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# leaking the password through the '/proc' filesystem.
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#
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# Heredocs are sometimes implemented via temporary files,
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# however this is typically done using 'mkstemp()' which
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# is more secure than a leak in '/proc'.
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pubkey=$(sed -n 's/.*\(age\)/\1/p' ~/.age/key.txt)
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age -r "$pubkey" -o "$name.age" <<-EOF &&
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$pass
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EOF
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printf '%s\n' "Saved '$name' to the store."
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}
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pw_del() {
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yn "Delete pass file '$1'?" && {
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rm -f "$1.age"
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# Remove empty parent directories of a password
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# entry. It's fine if this fails as it means that
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# another entry also lives in the same directory.
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rmdir -p "${1%/*}" 2>/dev/null || :
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}
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}
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pw_show() {
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age -i ~/.age/key.txt --decrypt "$1.age"
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}
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pw_list() {
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find . -type f -name \*.age | sed 's/..//;s/\.age$//'
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}
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pw_gen() {
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if yn "$HOME/.age/key.txt not detected, generate a new one?"; then
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mkdir -p ~/.age
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age-keygen -o ~/.age/key.txt
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fi
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}
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yn() {
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printf '%s [y/n]: ' "$1"
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# Enable raw input to allow for a single byte to be read from
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# stdin without needing to wait for the user to press Return.
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stty -icanon
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# Read a single byte from stdin using 'dd'. POSIX 'read' has
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# no support for single/'N' byte based input from the user.
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answer=$(dd ibs=1 count=1 2>/dev/null)
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# Disable raw input, leaving the terminal how we *should*
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# have found it.
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stty icanon
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printf '\n'
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# Handle the answer here directly, enabling this function's
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# return status to be used in place of checking for '[yY]'
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# throughout this program.
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glob "$answer" '[yY]'
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}
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sread() {
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printf '%s: ' "$2"
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# Disable terminal printing while the user inputs their
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# password. POSIX 'read' has no '-s' flag which would
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# effectively do the same thing.
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stty -echo
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read -r "$1"
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stty echo
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printf '\n'
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}
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glob() {
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# This is a simple wrapper around a case statement to allow
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# for simple string comparisons against globs.
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#
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# Example: if glob "Hello World" '* World'; then
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#
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# Disable this warning as it is the intended behavior.
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# shellcheck disable=2254
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case $1 in $2) return 0; esac; return 1
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}
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die() {
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printf 'error: %s.\n' "$1" >&2
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exit 1
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}
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usage() { printf %s "\
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pa 0.1.0 - age-based password manager
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=> [a]dd [name] - Create a new password, randomly generated
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=> [d]el [name] - Delete a password entry.
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=> [l]ist - List all entries.
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=> [s]how [name] - Show password for an entry.
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Password length: export PA_LENGTH=50
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Password pattern: export PA_PATTERN=_A-Z-a-z-0-9
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Store location: export PA_DIR=~/.local/share/pa
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"
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exit 0
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}
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main() {
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: "${PA_DIR:=${XDG_DATA_HOME:=$HOME/.local/share}/pa}"
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command -v age >/dev/null 2>&1 ||
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die "age not found, install per https://github.com/FiloSottile/age"
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command -v age-keygen >/dev/null 2>&1 ||
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die "age-keygen not found, install per https://github.com/FiloSottile/age"
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mkdir -p "$PA_DIR" ||
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die "Couldn't create password directory"
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cd "$PA_DIR" ||
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die "Can't access password directory"
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[ -f ~/.age/key.txt ] || pw_gen
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glob "$1" '[acds]*' && [ -z "$2" ] &&
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die "Missing [name] argument"
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glob "$1" '[cds]*' && [ ! -f "$2.age" ] &&
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die "Pass file '$2' doesn't exist"
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glob "$1" 'a*' && [ -f "$2.age" ] &&
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die "Pass file '$2' already exists"
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glob "$2" '*/*' && glob "$2" '*../*' &&
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die "Category went out of bounds"
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glob "$2" '/*' &&
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die "Category can't start with '/'"
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glob "$2" '*/*' && { mkdir -p "${2%/*}" ||
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die "Couldn't create category '${2%/*}'"; }
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# Restrict permissions of any new files to
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# only the current user.
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umask 077
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# Ensure that we leave the terminal in a usable
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# state on exit or Ctrl+C.
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[ -t 1 ] && trap 'stty echo icanon' INT EXIT
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case $1 in
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a*) pw_add "$2" ;;
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d*) pw_del "$2" ;;
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s*) pw_show "$2" ;;
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l*) pw_list ;;
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*) usage
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esac
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}
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# Ensure that debug mode is never enabled to
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# prevent the password from leaking.
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set +x
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# Ensure that globbing is globally disabled
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# to avoid insecurities with word-splitting.
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set -f
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[ "$1" ] || usage && main "$@"