name : crypt-gpg-lib.sh #!/bin/sh command -v ask_for_password >/dev/null || . /lib/dracut-crypt-lib.sh # gpg_decrypt mnt_point keypath keydev device # # Decrypts symmetrically encrypted (password or OpenPGP smartcard) key to standard output. # # mnt_point - mount point where <keydev> is already mounted # keypath - GPG encrypted key path relative to <mnt_point> # keydev - device on which key resides; only to display in prompt # device - device to be opened by cryptsetup; only to display in prompt gpg_decrypt() { local mntp="$1" local keypath="$2" local keydev="$3" local device="$4" local gpghome=/tmp/gnupg local opts="--homedir $gpghome --no-mdc-warning --skip-verify --quiet" opts="$opts --logger-file /dev/null --batch --no-tty --passphrase-fd 0" mkdir -m 0700 -p "$gpghome" # Setup GnuPG home and gpg-agent for usage of OpenPGP smartcard. # This requires GnuPG >= 2.1, as it uses the new ,,pinentry-mode´´ # feature, which - when set to ,,loopback´´ - allows us to pipe # the smartcard's pin to GnuPG (instead of using a normal pinentry # program needed with GnuPG < 2.1), making for uncomplicated # integration with the existing codebase. local useSmartcard="0" local gpgMajorVersion="$(gpg --version | sed -n 1p | sed -n -r -e 's|.* ([0-9]*).*|\1|p')" local gpgMinorVersion="$(gpg --version | sed -n 1p | sed -n -r -e 's|.* [0-9]*\.([0-9]*).*|\1|p')" if [ "${gpgMajorVersion}" -ge 2 ] && [ "${gpgMinorVersion}" -ge 1 ] \ && [ -f /root/crypt-public-key.gpg ] && getargbool 1 rd.luks.smartcard ; then useSmartcard="1" echo "allow-loopback-pinentry" >> "$gpghome/gpg-agent.conf" GNUPGHOME="$gpghome" gpg-agent --quiet --daemon GNUPGHOME="$gpghome" gpg --quiet --no-tty --import < /root/crypt-public-key.gpg local smartcardSerialNumber="$(GNUPGHOME=$gpghome gpg --no-tty --card-status \ | sed -n -r -e 's|Serial number.*: ([0-9]*)|\1|p' | tr -d '\n')" if [ -n "${smartcardSerialNumber}" ]; then inputPrompt="PIN (OpenPGP card ${smartcardSerialNumber})" fi GNUPGHOME="$gpghome" gpg-connect-agent 1>/dev/null learn /bye opts="$opts --pinentry-mode=loopback" fi ask_for_password \ --cmd "gpg $opts --decrypt $mntp/$keypath" \ --prompt "${inputPrompt:-Password ($keypath on $keydev for $device)}" \ --tries 3 --tty-echo-off # Clean up the smartcard gpg-agent if [ "${useSmartcard}" == "1" ]; then GNUPGHOME="$gpghome" gpg-connect-agent 1>/dev/null killagent /bye fi rm -rf -- "$gpghome" }