CP-12693 Sign kernel modules and image during kernel build (no shim)

CP-12694 Sign ZFS modules after ZFS build (no shim)
CP-12695 Sign connstat module after build (no shim)

PR URL: https://www.github.com/delphix/linux-pkg/pull/371

Author: tonynguien

default-package-config.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 #
-# Copyright 2018, 2020 Delphix
+# Copyright 2018, 2025 Delphix
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -160,6 +160,44 @@ function kernel_build() {
 	#
 	logmust fakeroot debian/rules printenv "${debian_rules_args[@]}"
 
+	#
+	# Configure signing keys/certs before build
+	#
+	# CONFIG_MODULE_SIG_KEY is set to /var/tmp/sbkeys/signing_key.pem in
+	# resources/delphix_kernel_annotations
+	#
+	FLAVOUR=$platform
+	OBJ=debian/build/build-$FLAVOUR
+	CERTS=$OBJ/certs
+
+	# ensure the objdir + certs dir exist
+	mkdir -p "$CERTS"
+	download_keys
+
+	# provide the key the packaging expects INSIDE the objdir
+	# (symlink or copy)
+	logmust ln -sf "${SB_KEYS_DIR}/signing_key.pem" "$CERTS/signing_key.pem"
+	logmust chmod 600 "$CERTS/signing_key.pem"
+
+	# create the DER .x509 that sign-file needs from .crt)
+	logmust openssl x509 -in "${SB_KEYS_DIR}/db.crt" -outform DER -out "$CERTS/signing_key.x509"
+
+	# sanity checks
+	logmust test -s "$CERTS/signing_key.pem" || {
+		echo "missing signing_key.pem"
+		exit 1
+	}
+	logmust test -s "$CERTS/signing_key.x509" || {
+		echo "missing signing_key.x509"
+		exit 1
+	}
+	logmust openssl pkey -in "$CERTS/signing_key.pem" -noout >/dev/null || {
+		echo "key unreadable"
+		exit 1
+	}
+	SBSIGN_KEY="${SBSIGN_KEY:-$SB_KEYS_DIR/db.key}"
+	SBSIGN_CERT="${SBSIGN_CERT:-$SB_KEYS_DIR/db.crt}"
+
 	#
 	# The default value of the tool argument for mk-build-deps
 	# is the following:
@@ -203,6 +241,23 @@ function kernel_build() {
 	# one of the .debs produced
 	#
 	logmust test -f "artifacts/linux-image-${kernel_version}_"*.deb
+
+	#
+	# After the build, unpackage linux-image package and sign vmlinuz
+	#
+	linux_deb=$(find artifacts -type f -name "linux-image-${kernel_version}*.deb" | head -n1)
+	temp_dir=$(mktemp -d -p "/var/tmp/")
+	logmust fakeroot dpkg-deb -R $linux_deb "$temp_dir"
+
+	bz="$temp_dir/boot/vmlinuz-${kernel_version}"
+	logmust sbsign --key $SBSIGN_KEY --cert $SBSIGN_CERT --output "$bz.signed" "$bz"
+	logmust mv "$bz.signed" "$bz"
+	logmust sbverify --list "$bz"
+
+	# Repack the .deb"
+	update_md5sums "$temp_dir"
+	repack_deb $linux_deb $temp_dir
+	delete_keys
 }
 
 #

lib/common.sh

@@ -1414,3 +1414,87 @@ function set_secret_build_args() {
 		_SECRET_BUILD_ARGS+=("-DSECRET_DB_AWS_REGION=$SECRET_DB_AWS_REGION")
 	fi
 }
+
+#
+# Secure boot variables and functions
+#
+# S3 bucket containing keys and certs
+# ./db subdirectory contains the db key and various certs:
+#   .der is for signing modules like ZFS and connstat
+#   .crt is for signing vmlinuz
+#   signing_key.pem is the format expected by kernel build for signing its modules
+#
+# ./pub contains the auth files, secure boot enrollment certs.
+#
+S3_KEYS_URL="s3://secure-boot-keys-prod/release"
+#
+# The kernel build expects the signing_key.pem in this directory, i.e.
+# CONFIG_MODULE_SIG_KEY is set to /var/tmp/sbkeys/signing_key.pem in
+# resources/delphix_kernel_annotations
+#
+SB_KEYS_DIR="/var/tmp/sbkeys"
+SBSIGN_KEY="$SB_KEYS_DIR/db.key"
+SBSIGN_DER="$SB_KEYS_DIR/db.der"
+
+function download_keys() {
+	logmust mkdir -p $SB_KEYS_DIR
+	logmust aws s3 cp --recursive "$S3_KEYS_URL/db/" $SB_KEYS_DIR
+}
+
+function delete_keys() {
+	logmust rm -r $SB_KEYS_DIR
+}
+
+# Update DEBIAN/md5sum for package directory after
+# some files were updated, i.e. secure-boot signed.
+#
+function update_md5sums() {
+	pkg_dir=$1
+	echo_bold "Updating md5sums for $pkg_dir"
+
+	(
+		cd "$pkg_dir" || exit
+		: >DEBIAN/md5sums
+		# print paths relative to root of package
+		while IFS= read -r -d '' f; do
+			rel="${f#./}"
+			md5sum "$rel" >>DEBIAN/md5sums
+		done < <(find . -type f ! -path './DEBIAN/*' ! -path './etc/depmod*' -print0)
+	)
+}
+
+function repack_deb() {
+	deb_name=$1
+	deb_dir=$2
+	temp_deb=$(mktemp /tmp/deb.XXXXXX)
+
+	logmust fakeroot dpkg-deb -b "$deb_dir" "$temp_deb"
+	logmust mv "$temp_deb" "$deb_name"
+}
+
+#
+# Sign .ko files in the module list
+#
+function sign_modules() {
+	deb_pkgs="$1"
+	echo_bold "Signing $deb_pkgs"
+	download_keys
+
+	while IFS= read -r pkg; do
+		echo_bold "Processing $pkg"
+		temp_dir=$(mktemp -d -p "/var/tmp/")
+		logmust fakeroot dpkg-deb -R "$pkg" "$temp_dir"
+
+		# Find and sign all .ko files in package
+		find "$temp_dir" -type f -name "*.ko" -print0 |
+			while IFS= read -r -d '' kernel_mod; do
+				logmust kmodsign sha256 "$SBSIGN_KEY" "$SBSIGN_DER" "$kernel_mod" "$kernel_mod.signed"
+				logmust mv "$kernel_mod.signed" "$kernel_mod"
+				logmust modinfo -F signer "$kernel_mod"
+			done
+		# Repack the .deb"
+		update_md5sums "$temp_dir"
+		repack_deb "$pkg" "$temp_dir"
+	done <<<"$deb_pkgs"
+	delete_keys
+}

packages/connstat/config.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 #
-# Copyright 2018, 2020 Delphix
+# Copyright 2018, 2025 Delphix
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -50,4 +50,8 @@ function build() {
 
 	logmust cd "$WORKDIR/repo"
 	logmust mv ./*deb "$WORKDIR/artifacts/"
+
+	# Sign the generated modules
+	connstat_pkgs=$(find "$WORKDIR/artifacts" -type f -name "connstat-module-*.deb" ! -name "*-dbg*")
+	sign_modules "$connstat_pkgs"
 }

packages/zfs/config.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 #
-# Copyright 2019, 2020 Delphix
+# Copyright 2019, 2025 Delphix
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -174,6 +174,10 @@ function build() {
 	done
 	logmust cd "$WORKDIR"
 	logmust mv "all-packages/"*.deb "artifacts/"
+
+	# Sign ZFS modules in all packages
+	zfs_pkgs=$(find "$WORKDIR/artifacts" -type f -name "zfs-modules-*.deb" ! -name "*-dbg*")
+	sign_modules "$zfs_pkgs"
 }
 
 function update_upstream() {

resources/delphix_kernel_annotations

@@ -2,6 +2,9 @@
 # FORMAT: 4
 # ARCH: amd64
 # FLAVOUR: amd64-aws amd64-azure amd64-generic amd64-gcp amd64-oracle
+#
+CONFIG_MODULE_SIG_KEY  		policy<{'amd64': '"/var/tmp/sbkeys/signing_key.pem"'}>
+CONFIG_MODULE_SIG_FORCE 			policy<{'amd64': 'y', 'arm64': 'n'}>
 
 #
 # Disable various "net" modules which we don't use.