j-hpn-ssh/contrib/ssh-copy-id

#!/usr/bin/env sh

# Copyright (c) 1999-2020 Philip Hands <phil@hands.com>
#               2020 Matthias Blümel <blaimi@blaimi.de>
#               2017 Sebastien Boyron <seb@boyron.eu>
#               2013 Martin Kletzander <mkletzan@redhat.com>
#               2010 Adeodato =?iso-8859-1?Q?Sim=F3?= <asp16@alu.ua.es>
#               2010 Eric Moret <eric.moret@gmail.com>
#               2009 Xr <xr@i-jeuxvideo.com>
#               2007 Justin Pryzby <justinpryzby@users.sourceforge.net>
#               2004 Reini Urban <rurban@x-ray.at>
#               2003 Colin Watson <cjwatson@debian.org>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

# Shell script to install your public key(s) on a remote machine
# See the ssh-copy-id(1) man page for details

# shellcheck shell=dash

# check that we have something mildly sane as our shell, or try to find something better
if false ^ printf "%s: WARNING: ancient shell, hunting for a more modern one... " "$0"; then
	SANE_SH=${SANE_SH:-/usr/bin/ksh}
	if printf 'true ^ false\n' | "$SANE_SH"; then
		printf "'%s' seems viable.\\n" "$SANE_SH"
		exec "$SANE_SH" "$0" "$@"
	else
		cat <<- EOF
			oh dear.

			  If you have a more recent shell available, that supports \$(...) etc.
			  please try setting the environment variable SANE_SH to the path of that
			  shell, and then retry running this script. If that works, please report
			  a bug describing your setup, and the shell you used to make it work.

		EOF
		printf '%s: ERROR: Less dimwitted shell required.\n' "$0"
		exit 1
	fi
fi

# shellcheck disable=SC2010
DEFAULT_PUB_ID_FILE=$(ls -t "${HOME}"/.ssh/id*.pub 2> /dev/null | grep -v -- '-cert.pub$' | head -n 1)
SSH="ssh -a -x"
umask 0177

usage()
{
	printf 'Usage: %s [-h|-?|-f|-n|-s] [-i [identity_file]] [-p port] [-F alternative ssh_config file] [[-o <ssh -o options>] ...] [user@]hostname\n' "$0" >&2
	printf '\t-f: force mode -- copy keys without trying to check if they are already installed\n' >&2
	printf '\t-n: dry run    -- no keys are actually copied\n' >&2
	printf '\t-s: use sftp   -- use sftp instead of executing remote-commands. Can be useful if the remote only allows sftp\n' >&2
	printf '\t-h|-?: print this help\n' >&2
	exit 1
}

# escape any single quotes in an argument
quote()
{
	printf '%s\n' "$1" | sed -e "s/'/'\\\\''/g"
}

use_id_file()
{
	L_ID_FILE="$1"

	if [ -z "$L_ID_FILE" ]; then
		printf '%s: ERROR: no ID file found\n' "$0"
		exit 1
	fi

	if expr "$L_ID_FILE" : '.*\.pub$' > /dev/null; then
		PUB_ID_FILE="$L_ID_FILE"
	else
		PUB_ID_FILE="$L_ID_FILE.pub"
	fi

	[ "$FORCED" ] || PRIV_ID_FILE=$(dirname "$PUB_ID_FILE")/$(basename "$PUB_ID_FILE" .pub)

	# check that the files are readable
	for f in "$PUB_ID_FILE" ${PRIV_ID_FILE:+"$PRIV_ID_FILE"}; do
		ErrMSG=$( {
			:            < "$f"
		}                        2>&1)  || {
			L_PRIVMSG=""
			[  "$f" = "$PRIV_ID_FILE" ] && L_PRIVMSG="	(to install the contents of '$PUB_ID_FILE' anyway, look at the -f option)"
			printf  "\\n%s: ERROR: failed to open ID file '%s': %s\\n" "$0" "$f" "$(printf '%s\n%s\n' "$ErrMSG" "$L_PRIVMSG" | sed -e 's/.*: *//')"
			exit  1
		}
	done
	printf '%s: INFO: Source of key(s) to be installed: "%s"\n' "$0" "$PUB_ID_FILE" >&2
	GET_ID="cat \"$PUB_ID_FILE\""
}

if [ -n "$SSH_AUTH_SOCK" ] && ssh-add -L > /dev/null 2>&1; then
	GET_ID="ssh-add -L"
fi

while getopts "i:o:p:F:fnsh?" OPT; do
	case "$OPT" in
		i)
			[  "${SEEN_OPT_I}" ] && {
				printf   '\n%s: ERROR: -i option must not be specified more than once\n\n' "$0"
				usage
			}
			SEEN_OPT_I="yes"
			use_id_file  "${OPTARG:-$DEFAULT_PUB_ID_FILE}"
			;;
		o | p | F)
			SSH_OPTS="${SSH_OPTS:+$SSH_OPTS }-$OPT '$( quote "${OPTARG}")'"
			;;
		f)
			FORCED=1
			;;
		n)
			DRY_RUN=1
			;;
		s)
			SFTP=sftp
			;;
		h | \?)
			usage
			;;
	esac
done
#shift all args to keep only USER_HOST
shift $((OPTIND - 1))

if [ $# = 0 ]; then
	usage
fi
if [ $# != 1 ]; then
	printf '%s: ERROR: Too many arguments.  Expecting a target hostname, got: %s\n\n' "$0" "$SAVEARGS" >&2
	usage
fi

# drop trailing colon
USER_HOST="$*"
# tack the hostname onto SSH_OPTS
SSH_OPTS="${SSH_OPTS:+$SSH_OPTS }'$(quote "$USER_HOST")'"
# and populate "$@" for later use (only way to get proper quoting of options)
eval set -- "$SSH_OPTS"

# shellcheck disable=SC2086
if [ -z "$(eval $GET_ID)" ] && [ -r "${PUB_ID_FILE:=$DEFAULT_PUB_ID_FILE}" ]; then
	use_id_file "$PUB_ID_FILE"
fi

# shellcheck disable=SC2086
if [ -z "$(eval $GET_ID)" ]; then
	printf '%s: ERROR: No identities found\n' "$0" >&2
	exit 1
fi

# filter_ids()
# tries to log in using the keys piped to it, and filters out any that work
filter_ids()
{
	L_SUCCESS="$1"
	L_TMP_ID_FILE="$SCRATCH_DIR"/popids_tmp_id
	L_OUTPUT_FILE="$SCRATCH_DIR"/popids_output

	# repopulate "$@" inside this function
	eval set -- "$SSH_OPTS"

	while read -r ID || [ "$ID" ]; do
		printf '%s\n' "$ID" > "$L_TMP_ID_FILE"

		# the next line assumes $PRIV_ID_FILE only set if using a single id file - this
		# assumption will break if we implement the possibility of multiple -i options.
		# The point being that if file based, ssh needs the private key, which it cannot
		# find if only given the contents of the .pub file in an unrelated tmpfile
		$SSH -i "${PRIV_ID_FILE:-$L_TMP_ID_FILE}" \
			-o  ControlPath=none \
			-o  LogLevel=INFO \
			-o  PreferredAuthentications=publickey \
			-o  IdentitiesOnly=yes "$@" exit > "$L_OUTPUT_FILE" 2>&1 < /dev/null
		if [ "$?" = "$L_SUCCESS" ] || {
			[     "$SFTP" ] && grep 'allows sftp connections only' "$L_OUTPUT_FILE" > /dev/null
			# this error counts as a success if we're setting up an sftp connection
		}; then
			:  > "$L_TMP_ID_FILE"
		else
			grep  'Permission denied' "$L_OUTPUT_FILE" > /dev/null || {
				sed   -e 's/^/ERROR: /' < "$L_OUTPUT_FILE" > "$L_TMP_ID_FILE"
				cat   > /dev/null #consume the other keys, causing loop to end
			}
		fi

		cat "$L_TMP_ID_FILE"
	done
}

# populate_new_ids() uses several global variables ($USER_HOST, $SSH_OPTS ...)
# and has the side effect of setting $NEW_IDS
populate_new_ids()
{
	if [ "$FORCED" ]; then
		# shellcheck disable=SC2086
		NEW_IDS=$(eval $GET_ID)
		return
	fi

	printf '%s: INFO: attempting to log in with the new key(s), to filter out any that are already installed\n' "$0" >&2
	# shellcheck disable=SC2086
	NEW_IDS=$(eval $GET_ID | filter_ids $1)

	if expr "$NEW_IDS" : "^ERROR: " > /dev/null; then
		printf '\n%s: %s\n\n' "$0" "$NEW_IDS" >&2
		exit 1
	fi
	if [ -z "$NEW_IDS" ]; then
		printf '\n%s: WARNING: All keys were skipped because they already exist on the remote system.\n' "$0" >&2
		printf '\t\t(if you think this is a mistake, you may want to use -f option)\n\n' >&2
		exit 0
	fi
	printf '%s: INFO: %d key(s) remain to be installed -- if you are prompted now it is to install the new keys\n' "$0" "$(printf '%s\n' "$NEW_IDS" | wc -l)" >&2
}

# installkey_sh [target_path]
#    produce a one-liner to add the keys to remote authorized_keys file
#    optionally takes an alternative path for authorized_keys
installkeys_sh()
{
	AUTH_KEY_FILE=${1:-.ssh/authorized_keys}
	AUTH_KEY_DIR=$(dirname "${AUTH_KEY_FILE}")

	# In setting INSTALLKEYS_SH:
	#    the tr puts it all on one line (to placate tcsh)
	#      (hence the excessive use of semi-colons (;) )
	# then in the command:
	#    cd to be at $HOME, just in case;
	#    the -z `tail ...` checks for a trailing newline. The echo adds one if was missing
	#    the cat adds the keys we're getting via STDIN
	#    and if available restorecon is used to restore the SELinux context
	INSTALLKEYS_SH=$(
		tr                '\t\n' ' ' <<- EOF
			cd;
			umask 077;
			mkdir -p "${AUTH_KEY_DIR}" &&
				{ [ -z \`tail -1c ${AUTH_KEY_FILE} 2>/dev/null\` ] ||
					echo >> "${AUTH_KEY_FILE}" || exit 1; } &&
				cat >> "${AUTH_KEY_FILE}" || exit 1;
			if type restorecon >/dev/null 2>&1; then
				restorecon -F "${AUTH_KEY_DIR}" "${AUTH_KEY_FILE}";
			fi
		EOF
	)

	# to defend against quirky remote shells: use 'exec sh -c' to get POSIX;
	printf "exec sh -c '%s'" "${INSTALLKEYS_SH}"
}

#shellcheck disable=SC2120 # the 'eval set' confuses this
installkeys_via_sftp()
{

	# repopulate "$@" inside this function
	eval set -- "$SSH_OPTS"

	L_KEYS=$SCRATCH_DIR/authorized_keys
	L_SHARED_CON=$SCRATCH_DIR/master-conn
	$SSH -f -N -M -S "$L_SHARED_CON" "$@"
	L_CLEANUP="$SSH -S $L_SHARED_CON -O exit 'ignored' >/dev/null 2>&1 ; $SCRATCH_CLEANUP"
	#shellcheck disable=SC2064
	trap "$L_CLEANUP" EXIT TERM INT QUIT
	sftp -b - -o "ControlPath=$L_SHARED_CON" "ignored" <<- EOF || return 1
		-get .ssh/authorized_keys $L_KEYS
	EOF
	# add a newline or create file if it's missing, same like above
	[ -z "$(tail -1c "$L_KEYS" 2> /dev/null)" ] || echo >> "$L_KEYS"
	# append the keys being piped in here
	cat >> "$L_KEYS"
	sftp -b - -o "ControlPath=$L_SHARED_CON" "ignored" <<- EOF || return 1
		-mkdir .ssh
		chmod 700 .ssh
		put $L_KEYS .ssh/authorized_keys
		chmod 600 .ssh/authorized_keys
	EOF
	#shellcheck disable=SC2064
	eval "$L_CLEANUP" && trap "$SCRATCH_CLEANUP" EXIT TERM INT QUIT
}

# create a scratch dir for any temporary files needed
if SCRATCH_DIR=$(mktemp -d ~/.ssh/ssh-copy-id.XXXXXXXXXX) &&
	[  "$SCRATCH_DIR" ] && [ -d "$SCRATCH_DIR" ]; then
	chmod 0700 "$SCRATCH_DIR"
	SCRATCH_CLEANUP="rm -rf \"$SCRATCH_DIR\""
	#shellcheck disable=SC2064
	trap "$SCRATCH_CLEANUP" EXIT TERM INT QUIT
else
	printf '%s: ERROR: failed to create required temporary directory under ~/.ssh\n' "$0" >&2
	exit 1
fi

REMOTE_VERSION=$($SSH -v -o PreferredAuthentications=',' -o ControlPath=none "$@" 2>&1 |
	sed               -ne 's/.*remote software version //p')

# shellcheck disable=SC2029
case "$REMOTE_VERSION" in
	NetScreen*)
		populate_new_ids 1
		for KEY in $(printf "%s" "$NEW_IDS" | cut -d' ' -f2); do
			KEY_NO=$((KEY_NO + 1))
			printf  '%s\n' "$KEY" | grep ssh-dss > /dev/null || {
				printf    '%s: WARNING: Non-dsa key (#%d) skipped (NetScreen only supports DSA keys)\n' "$0" "$KEY_NO" >&2
				continue
			}
			[  "$DRY_RUN" ] || printf 'set ssh pka-dsa key %s\nsave\nexit\n' "$KEY" | $SSH -T "$@" > /dev/null 2>&1
			if  [ $? = 255 ]; then
				printf   '%s: ERROR: installation of key #%d failed (please report a bug describing what caused this, so that we can make this message useful)\n' "$0" "$KEY_NO" >&2
			else
				ADDED=$((ADDED + 1))
			fi
		done
		if [ -z "$ADDED" ]; then
			exit  1
		fi
		;;
	dropbear*)
		populate_new_ids 0
		[ "$DRY_RUN" ] || printf '%s\n' "$NEW_IDS" |
			$SSH  "$@" "$(installkeys_sh /etc/dropbear/authorized_keys)" ||
			exit     1
		ADDED=$(printf '%s\n' "$NEW_IDS" | wc -l)
		;;
	*)
		# Assuming that the remote host treats ~/.ssh/authorized_keys as one might expect
		populate_new_ids 0
		if ! [ "$DRY_RUN" ]; then
			printf  '%s\n' "$NEW_IDS" |
				if   [ "$SFTP" ]; then
					#shellcheck disable=SC2119
					installkeys_via_sftp
				else
					$SSH    "$@" "$(installkeys_sh)"
				fi   || exit 1
		fi
		ADDED=$(printf '%s\n' "$NEW_IDS" | wc -l)
		;;
esac

if [ "$DRY_RUN" ]; then
	cat <<- EOF
		=-=-=-=-=-=-=-=
		Would have added the following key(s):

		$NEW_IDS
		=-=-=-=-=-=-=-=
	EOF
else
	cat <<- EOF

		Number of key(s) added: $ADDED

		Now try logging into the machine, with:   "${SFTP:-ssh} $SSH_OPTS"
		and check to make sure that only the key(s) you wanted were added.

	EOF
fi

# =-=-=-=