diff options
Diffstat (limited to 'home/.local/bin/doasedit')
| -rwxr-xr-x | home/.local/bin/doasedit | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/home/.local/bin/doasedit b/home/.local/bin/doasedit new file mode 100755 index 0000000..a3bdb2d --- /dev/null +++ b/home/.local/bin/doasedit @@ -0,0 +1,202 @@ +#!/bin/sh -e + +help() { + cat - >&2 <<EOF +doasedit - edit non-user-editable files with an unprivileged editor + +usage: doasedit -h | -V +usage: doasedit file ... + +Options: + -h, --help display help message and exit + -V, --version display version information and exit + -- stop processing command line arguments + +Environment Variables: + DOAS_EDITOR program used to edit files + EDITOR program used to edit files if DOAS_EDITOR is unset + +To work properly doasedit needs to always start a new editor instance. Some +editors, graphical ones in particular, open files in previously running +instances. If so, append a command line argument to your (DOAS_)EDITOR variable +such that the editor will always start a new instance (e. g.: 'kate -n'). + +How it works: +Every File to be edited is duplicated to a user owned file in /tmp. The editor +is then run in user context. After closing the editor the user file replaces +the original file while preserving file attributes. All this is done using doas +as little as possible. Files are edited one after another, not all at once. +EOF +} + +# Checks for syntax errors in doas' config +# +# check_doas_conf <target> <tmp_target> +# +check_doas_conf() { + if printf '%s' "${1}" | grep -q '^/etc/doas\(\.d/.*\)\?\.conf$'; then + while ! doas -C "${2}"; do + printf "doasedit: Replacing '%s' would " "$file" + printf 'introduce the above error and break doas.\n' + printf '(E)dit again, (O)verwrite anyway, (A)bort: [E/o/a]? ' + read -r choice + case "$choice" in + o | O) + return 0 + ;; + a | A) + return 1 + ;; + e | E | *) + "$editor_cmd" "$tmpfile" + ;; + esac + done + fi + return 0 +} + +error() { + printf 'doasedit: %s\n' "${@}" 1>&2 +} + +_exit() { + rm -rf "$tmpdir" + trap - EXIT HUP QUIT TERM INT ABRT + exit "${1:-0}" +} + +# no argument passed +[ "${#}" -eq 0 ] && help && exit 1 + +while [ "${#}" -ne 0 ]; do + case "${1}" in + --) + shift + break + ;; + --help | -h) + help + exit 0 + ;; + --version | -V) + printf 'doasedit version 1.0.7\n' + exit 0 + ;; + -*) + printf "doasedit: invalid option: '%s'\n" "${1}" + help + exit 1 + ;; + *) + break + ;; + esac +done + +[ "$DOAS_EDITOR" != "" ] && editor_cmd="$DOAS_EDITOR" || editor_cmd="$EDITOR" +# shellcheck disable=SC2086 +if [ "$editor_cmd" = "" ]; then + if command -v vi >/dev/null 2>&1; then + editor_cmd='vi' + else + error 'no editor specified' + exit 1 + fi +elif ! command -v "$editor_cmd" >/dev/null 2>&1; then + error "invalid editor command: '${editor_cmd}'" + exit 1 +fi + +exit_code=1 +trap '_exit "${exit_code}"' EXIT +trap '_exit 130' HUP QUIT TERM INT ABRT +tmpdir="$(mktemp -dt 'doasedit-XXXXXX')" + +for file; do + unset exists readable writable + dir="$(dirname -- "$file")" + tmpfile="${tmpdir}/${file##*/}" + tmpfile_copy="${tmpdir}/copy-of-${file##*/}" + printf '' | tee "$tmpfile" >"$tmpfile_copy" + chmod 0600 "$tmpfile" "$tmpfile_copy" + + if [ -e "$file" ]; then + if ! [ -f "$file" ]; then + error "${file}: not a regular file" + continue + fi + # -O is not POSIX, but implemented at least in GNU, *BSD and macOS test + if [ -O "$file" ]; then + error "${file}: editing your own files is not permitted" + continue + fi + exists=1 + elif doas [ -e "$file" ]; then + if ! doas [ -f "$file" ]; then + error "${file}: not a regular file" + continue + fi + exists=0 + else + # New file? + if [ -O "$dir" ]; then + error "${file}: creating files in your own directory is not permitted" + continue + elif [ -x "$dir" ] && [ -w "$dir" ]; then + error "${file}: creating files in a user-writable directory is not permitted" + continue + elif ! doas [ -e "$dir" ]; then + error "${file}: no such directory" + continue + # else: root-writable directory + fi + fi + # If this test is true, it's an existent regular file + if [ "$exists" != "" ]; then + if [ -w "$file" ]; then + writable=1 + # Check in advance to make sure that it won't fail after editing. + elif ! doas dd status=none count=0 of=/dev/null; then + error "unable to run 'doas dd'" + continue + fi + if [ -r "$file" ]; then + if [ "$writable" != "" ]; then + error "${file}: editing user-readable and -writable files is not permitted" + continue + fi + # Read file + cat -- "$file" >"$tmpfile" + # Better not suppress stderr here as there might be something of importance. + elif ! doas cat -- "$file" >"$tmpfile"; then + error "you are not permitted to call 'doas cat'" + continue + fi + cat "$tmpfile" >"$tmpfile_copy" + fi + + "$editor_cmd" "$tmpfile" + + check_doas_conf "$file" "$tmpfile" || continue + if cmp -s "$tmpfile" "$tmpfile_copy"; then + printf 'doasedit: %s: unchanged\n' "$file" + else + if [ "$writable" != "" ]; then + dd status=none if="$tmpfile" of="$file" + else + for de_tries in 2 1 0; do + if doas dd status=none if="$tmpfile" of="$file"; then + break + elif [ "$de_tries" -eq 0 ]; then + error '3 incorrect password attempts' + exit 1 + fi + done + fi + fi + + exit_code=0 +done + +# vim: shiftwidth=2 tabstop=2 noexpandtab |