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