pesign(1)

NAME

pesign – tool for signing UEFI applications

SYNOPSIS

pesign -i file [-o file] [-f] [-n directory] [-t token] [-c nickname] [-u number] [-m file] [-e file] [-I file] [-E file] [-R file] [-K file] [-C file] [-a] [-l] [-S] [-v] [--pinfile file | --pwfile file]⟨ -s | -D [-N] | -r | -h [-d digest] [-P | -p]⟩

DESCRIPTION

pesign is a command line tool for manipulating signatures and cryptographic digests of UEFI applications.

OPTIONS

-i file | --in file

Input PE file for signing

-o file | --out file

Output PE file for signing

-f | --force

Overwrite existing file specified with --out

-n directory | --certdir directory

Use the NSS Database in directory( default: /etc/pki/pesign)

-t token | --token token

Use the NSS token named token

-c nickname | --certificate nickname

Use the certificate called nickname in the NSS Database

-u number | --signature-number number

Signature number, indexed from 0, for use with --remove-signature, --export-signature, or --show-signature( default: 0)

-m file | --import-signature file

Import Authenticode signature from file

-e file | --export-signature file

Export Authenticode signature to file

-I file | --import-signed-attributes file

Import PKCS-7 SignedAttributes (with no signature) from file

-E file | --export-signed-attributes file

Export PKCS-7 SignedAttributes (with no signature) to file

-R file | --import-raw-signature file

Import signature digest from file

-K file | --export-pubkey file

Export public key from the NSS Database specified by --token and --certificate to file

-C file | --export-cert file

Export certificate from the NSS Database specified by --token and --certificate to file

-a | --ascii-armor

When exporting certificates, encode them in ascii-armor

-l | --list-signatures

List signatures

-S | --show-signature

Show information about signatures

-v | --verbose

Be more verbose

-s | --sign

Create a new signature

-D | --daemonize

Run as a daemon

-N | --nofork

Do not fork when daemonizing( daemon runs in foreground)

-r | --remove-signature

Remove signature

-h | --hash

Display the Authenticode hash of the binary

-d digest | --digest-type digest

Use the cryptographic digest with --hash( use help to list options)( default: sha256)

-P | --padding | -p | --nopadding

Do or do not pad the binary according to PE 9.3 rules before signing or hashing( default: --padding)

Padding is recommended (and in many circumstances required) even for binaries which predate the current PE spec, and is enabled by default as of pesign 113.

--pinfile file | --pwfile file

Read token's password from file rather than from interactive prompt.

( the same can be accomplished by exporting the environment variable PESIGN_TOKEN_PIN)

EXAMPLES

Keep in mind that the following examples assume that /etc/pki/pesign is the certificate database. To make use of it as a regular user, add yourself to the pesign Unix group with

sudo usermod -a -G pesign $USER

Signing with the certificate and private key in individual files

If you have a certificate file and private key file, the following steps may be used to sign a PE image:

# Create a pkcs12 file from private key and certificate file.
host:~$ openssl pkcs12 -export -out foo_key.p12 \
        -inkey signing_key.pem -in xyz_cert.x509.pem
# Import pkcs12 file into pesign db
host:~$ pk12util -i foo_key.p12 -d /etc/pki/pesign
# Do the signing
host:~$ pesign -c my-signing-cert -s \
        -i foo.unsigned.efi -o foo.signed.efi

Please note that this is just an example, and that recommended best practice is to always store private keys in a FIPS 140-2 Hardware Security Module (HSM), level 2 or higher.

Signing using an HSM

If you have a key pair in your HSM and your HSM vendor provides a PKCS-11 library, you can use it with NSS directly:

# Add the HSM PKCS-11 library to the NSS database
host:~$ modutil -dbdir /etc/pki/pesign -add vendor-engine \
        -libfile /usr/lib64/pkcs11/vendor-engine.so
WARNING: Performing this operation while the browser is running
could cause corruption of your security databases. If the browser
is currently running, you should exit browser before continuing
this operation. Type
'q <enter>' to abort, or <enter> to continue: <type enter here>
Module "vendor-engine" added to database.
# List the added module
host:~$ modutil -dbdir /etc/pki/pesign -list
-----------------------------------------------------------
  1. NSS Internal PKCS #11 Module
	   uri: pkcs11:library-manufacturer=Mozilla%20Foundation;library-description=NSS%20Internal%20Crypto%20Services;library-version=3.52
	 slots: 2 slots attached
	status: loaded
	 slot: NSS Internal Cryptographic Services
	token: NSS Generic Crypto Services
	  uri: pkcs11:token=NSS%20Generic%20Crypto%20Services;manufacturer=Mozilla%20Foundation;serial=0000000000000000;model=NSS%203
	 slot: NSS User Private Key and Certificate Services
	token: NSS Certificate DB
	  uri: pkcs11:token=NSS%20Certificate%20DB;manufacturer=Mozilla%20Foundation;serial=0000000000000000;model=NSS%203
  2. opensc-pkcs11.so
	library name: /usr/lib64/pkcs11/opensc-pkcs11.so
	   uri: pkcs11:library-manufacturer=OpenSC%20Project;library-description=OpenSC%20smartcard%20framework;library-version=0.20
	 slots: 1 slot attached
	status: loaded
	 slot: Generic Smart Card Reader Interface [Smart Card Reader Interf...
	token: OpenSC Card (myorg-sb-signer)
	  uri: pkcs11:token=OpenSC%20Card%20(myorg-sb-signer);manufacturer=OpenSC%20Project;serial=56516a130f35;model=PKCS%2315
-----------------------------------------------------------
# List certs in tokens
host:~$ certutil -d /etc/pki/pesign \
        -h "OpenSC Card (myorg-sb-signer)" -L
Certificate Nickname                             Trust Attributes
                                                 SSL,S/MIME,JAR/XPI
Enter Password or Pin for "OpenSC Card (myorg-sb-signer)": <type the PIN here>
OpenSC Card (myorg-sb-signer):/CN=My Org's SB Signer    u,u,u
# Sign with private key in HSM
host:~$ pesign -t "OpenSC Card (myorg-sb-signer)" \
        -c "OpenSC Card (myorg-sb-signer):/CN=My Org's SB Signer" \
        -s -i foo.unsigned.efi -o foo.efi

Example with OpenDNSSEC's SoftHSM

The OpenDNSSEC project provides a software implementation of a generic cryptographic device with a PKCS#11 interface - SoftHSM.

SoftHSM, OpenDNSSEC, https://www.opendnssec.org/softhsm/ .

This project may come in handy as one can practice how HSMs work without the need to have a physical HSM.

In this example we'll initialize one token, generate a CA certificate directly in it and make pesign ask it for the generated object to sign a shimx64 binary.

Please note that this is just an example and was written purely for demonstration purposes. Use hardware tokens, strong passwords and don't store these in plaintext directly in filesystem.

https://www.opendnssec.org/softhsm/

# Initialize a SoftHSM token
host:~$ mkdir -p $HOME/.config/softhsm2/tokens
host:~$ echo "directories.tokendir = $HOME/.config/softhsm2/tokens" > $HOME/.config/softhsm2/softhsm2.conf
host:~$ softhsm2-util --init-token --label HSM --so-pin Secret.123 --pin Secret.123 --free
# Store this PIN in a file
host:~$ cat ~/pwfile.txt
Secret.123
# Generate a CA directly in this token
host:~$ efikeygen -t HSM -d /etc/pki/pesign -n example \
        --ca --self-sign --common-name "CN=example,OU=example,O=example" --kernel
# Confirm the certificate is really in there
host:~$ certutil -d /etc/pki/pesign -h HSM -L
Certificate Nickname                                         Trust Attributes
                                                             SSL,S/MIME,JAR/XPI
Enter Password or Pin for "HSM": <type the PIN 'Secret.123' here>
HSM:example                                                  u,u,u
# Do the signing
host:~$ pesign -t HSM -n /etc/pki/pesign -c example \
        -i ~/shimx64.efi.unsigned -o ~/shimx64.efi.signed \
        --pinfile ~/pwfile.txt -s

Signing using an HSM with an OpenSSL Engine

If you have a key pair in your HSM but can't access it directly, but do have access to the openssl command line tool configured with your vendor's libraries, you can still use pesign to sign your PE binaries:

# Import the public certificate into the NSS Database
host:~$ certutil -d /etc/pki/pesign -A -n myorg-sb-signer \
        -t ,,u -i myorg-sb-signer.cer
# Export the PKCS-7 SignedAttributes section pesign generates
host:~$ pesign -i foo.unsigned.efi -E foo.sattrs.bin
# Generate a signature using OpenSSL
host:~$ openssl dgst -sha256 -sign $KEY \
        --keyform ENGINE --engine $ENGINEID \
        -out foo.sattrs.sig foo.sattrs.bin
# Import the signature with the original SignedAttributes into
# the PE binary
host:~$ pesign -c myorg-sb-signer \
        -R foo.sattrs.sig -I foo.sattrs.bin \
        -i foo.unsigned.efi -o foo.efi

STANDARDS

B. Kaliski, PKCS #7: Cryptographic Message Syntax v1.5, RFC 2315, Internet Engineering Task Force, March 1998, https://tools.ietf.org/html/rfc2315 .

K. Moriarty, M. Nyström, S. Parkinson, A. Rusch, and M. Scott, PKCS #12: Personal Information Exchange Syntax v1.1, RFC 7292, Internet Engineering Task Force, July 2014, https://tools.ietf.org/html/rfc7292 .

PKCS11 Technical Committee, PKCS#11: Cryptographic Token Interface Standard, OASIS, https://www.cryptsoft.com/pkcs11doc/.

M. Nyström, PKCS #15—A Cryptographic-Token Information Format Standard, RSA Laboratories, 1999, https://www.usenix.org/legacy/events/smartcard99/full_papers/nystrom/nystrom.pdf .

Portable Executable, Microsoft, August 26, 2019, https://docs.microsoft.com/en-us/windows/win32/debug/pe-format .

Windows Authenticode Portable Executable Signature Format, Microsoft, March 21, 2008, https://web.archive.org/web/20130518222430/http://download.microsoft.com/download/9/c/5/9c5b2167-8017-4bae-9fde-d599bac8184a/Authenticode_PE.docx .

Federal Information Processing Standard 140-2, FIPS 140-2, United States Department of Commerce, National Institute of Standards and Technology, http://csrc.nist.gov/publications/PubsFIPS.html .

AUTHORS

Peter Jones Vikas Charak (examples) Kamil Aronowski (fixes and improvements)