systemd-sbsign

systemd

systemd-sbsign

Sign PE binaries for EFI Secure Boot

systemd-sbsign

OPTIONS

COMMAND

Description

systemd-sbsign can be used to sign PE binaries for EFI Secure Boot.

Commands

sign
Signs the given PE binary for EFI Secure Boot. Takes a path to a PE binary as its argument. If the PE binary already has a certificate table, the new signature will be added to it. Otherwise, a new certificate table will be created. The signed PE binary will be written to the path specified with --output=.

Options

The following options are understood:

--output=PATH
Specifies the path where to write the signed PE binary or the data to be signed offline when using the --prepare-offline-signing option.

--private-key=PATH/URI; --private-key-source=TYPE[:NAME]; --certificate=PATH; --certificate-source=TYPE[:NAME]
Set the Secure Boot private key and certificate for use with the sign verb. The --certificate= option takes a path to a PEM-encoded X.509 certificate or a URI that's passed to the OpenSSL provider configured with --certificate-source=. The --certificate-source= option takes one of file or provider, with the latter being followed by a specific provider identifier, separated with a colon, e.g. provider:pkcs11. The --private-key= option takes a path or a URI that will be passed to the OpenSSL engine or provider, as specified by --private-key-source= as a type:name tuple, such as engine:pkcs11. The specified OpenSSL signing engine or provider will be used to sign the PE binary.

--prepare-offline-signing
When this option is specified, the sign command writes the data that should be signed to the path specified with --output= instead of writing the signed PE binary. This data can then be signed out of band after which the signature can be attached to the PE binary using the --signed-data= and --signed-data-signature= options.

--signed-data=PATH; --signed-data-signature=PATH
Configure the signed data (as written to the path specified with --output= when using the --prepare-offline-signing option) and corresponding signature for the sign command.

Examples

Offline EFI secure boot signing of a PE binary

The following does offline secure boot signing of systemd-boot:

SD_BOOT="$(find /usr/lib/systemd/boot/efi/ -name "systemd-boot*.efi" | head -n1)"
# Extract the data that should be signed offline.
/usr/lib/systemd/systemd-sbsign \
    sign \
    --certificate=secure-boot-certificate.pem \
    --output=signed-data.bin \
    --prepare-offline-signing \
    "$SD_BOOT"
# Sign the data out-of-band. This step usually happens out-of-band on a separate system.
openssl dgst -sha256 -sign secure-boot-private-key.pem -out signed-data.sig signed-data.bin
# Attach the signed data and its signature to the systemd-boot PE binary.
/usr/lib/systemd/systemd-sbsign \
    sign \
    --certificate=secure-boot-certificate.pem \
    --output="$SD_BOOT.signed" \
    --signed-data=signed-data.bin \
    --signed-data-signature=signed-data.sig \
    "$SD_BOOT"