# $OpenBSD: keys-command.sh,v 1.8 2021/09/30 04:22:50 dtucker Exp $ # Placed in the Public Domain. tid="authorized keys from command" if [ -z "$SUDO" -a ! -w /var/run ]; then skip "need SUDO to create file in /var/run, test won't work without" fi rm -f $OBJ/keys-command-args touch $OBJ/keys-command-args chmod a+rw $OBJ/keys-command-args expected_key_text=`awk '{ print $2 }' < $OBJ/ssh-ed25519.pub` expected_key_fp=`$SSHKEYGEN -lf $OBJ/ssh-ed25519.pub | awk '{ print $2 }'` # Establish a AuthorizedKeysCommand in /var/run where it will have # acceptable directory permissions. KEY_COMMAND="/var/run/keycommand_${LOGNAME}.$$" trap "${SUDO} rm -f ${KEY_COMMAND}" 0 cat << _EOF | $SUDO sh -c "rm -f '$KEY_COMMAND' ; cat > '$KEY_COMMAND'" #!/bin/sh echo args: "\$@" >> $OBJ/keys-command-args echo "$PATH" | grep -q mekmitasdigoat && exit 7 test "x\$1" != "x${LOGNAME}" && exit 1 if test $# -eq 6 ; then test "x\$2" != "xblah" && exit 2 test "x\$3" != "x${expected_key_text}" && exit 3 test "x\$4" != "xssh-rsa" && exit 4 test "x\$5" != "x${expected_key_fp}" && exit 5 test "x\$6" != "xblah" && exit 6 fi exec cat "$OBJ/authorized_keys_${LOGNAME}" _EOF $SUDO chmod 0755 "$KEY_COMMAND" if [ -x $KEY_COMMAND ]; then cp $OBJ/sshd_proxy $OBJ/sshd_proxy.bak verbose "AuthorizedKeysCommand with arguments" ( grep -vi AuthorizedKeysFile $OBJ/sshd_proxy.bak echo AuthorizedKeysFile none echo AuthorizedKeysCommand $KEY_COMMAND %u blah %k %t %f blah echo AuthorizedKeysCommandUser ${LOGNAME} ) > $OBJ/sshd_proxy # Ensure that $PATH is sanitised in sshd env PATH=$PATH:/sbin/mekmitasdigoat \ ${SSH} -F $OBJ/ssh_proxy somehost true if [ $? -ne 0 ]; then fail "connect failed" fi verbose "AuthorizedKeysCommand without arguments" # Check legacy behavior of no-args resulting in username being passed. ( grep -vi AuthorizedKeysFile $OBJ/sshd_proxy.bak echo AuthorizedKeysFile none echo AuthorizedKeysCommand $KEY_COMMAND echo AuthorizedKeysCommandUser ${LOGNAME} ) > $OBJ/sshd_proxy # Ensure that $PATH is sanitised in sshd env PATH=$PATH:/sbin/mekmitasdigoat \ ${SSH} -F $OBJ/ssh_proxy somehost true if [ $? -ne 0 ]; then fail "connect failed" fi else skip "$KEY_COMMAND not executable (/var/run mounted noexec?)" fi