From d1ab18f327634fe9175848237eac8a1cde9361ac Mon Sep 17 00:00:00 2001 From: Nikita Dubrovskii Date: Mon, 17 Jan 2022 15:59:54 +0100 Subject: [PATCH] s390x: add LUKS keyfile to 'sd-boot' This allows to use Secure Execution with LUKS encrypted boot disk, key and cryptab are stored only in 'sd-boot' encrypted image. Signed-off-by: Nikita Dubrovskii --- Makefile-libostree.am | 9 +++-- src/libostree/ostree-bootloader-zipl.c | 50 ++++++++++++++++++++++++-- src/libostree/s390x-se-luks-gencpio | 22 ++++++++++++ 3 files changed, 77 insertions(+), 4 deletions(-) create mode 100755 src/libostree/s390x-se-luks-gencpio diff --git a/Makefile-libostree.am b/Makefile-libostree.am index c9511fe3..02ae9c6a 100644 --- a/Makefile-libostree.am +++ b/Makefile-libostree.am @@ -184,7 +184,8 @@ EXTRA_DIST += \ libostree_1_la_CFLAGS = $(AM_CFLAGS) -I$(srcdir)/bsdiff -I$(srcdir)/libglnx -I$(srcdir)/src/libotutil -I$(srcdir)/src/libostree -I$(builddir)/src/libostree \ $(OT_INTERNAL_GIO_UNIX_CFLAGS) $(OT_INTERNAL_GPGME_CFLAGS) $(OT_DEP_LZMA_CFLAGS) $(OT_DEP_ZLIB_CFLAGS) $(OT_DEP_CRYPTO_CFLAGS) \ - -fvisibility=hidden '-D_OSTREE_PUBLIC=__attribute__((visibility("default"))) extern' + -fvisibility=hidden '-D_OSTREE_PUBLIC=__attribute__((visibility("default"))) extern' \ + -DPKGLIBEXECDIR=\"$(pkglibexecdir)\" libostree_1_la_LDFLAGS = -version-number 1:0:0 -Bsymbolic-functions $(addprefix $(wl_versionscript_arg),$(symbol_files)) libostree_1_la_LIBADD = libotutil.la libglnx.la libbsdiff.la $(OT_INTERNAL_GIO_UNIX_LIBS) $(OT_INTERNAL_GPGME_LIBS) \ $(OT_DEP_LZMA_LIBS) $(OT_DEP_ZLIB_LIBS) $(OT_DEP_CRYPTO_LIBS) @@ -292,8 +293,12 @@ EXTRA_DIST += src/libostree/README-gpg src/libostree/bupsplit.h \ src/libostree/ostree-enumtypes.c.template \ src/libostree/ostree-deployment-private.h \ src/libostree/ostree-repo-deprecated.h \ - src/libostree/ostree-version.h + src/libostree/ostree-version.h \ + src/libostree/s390x-se-luks-gencpio install-mkdir-remotes-d-hook: mkdir -p $(DESTDIR)$(sysconfdir)/ostree/remotes.d INSTALL_DATA_HOOKS += install-mkdir-remotes-d-hook + +# Secure Execution: script for creating new initramdisk with LUKS key and config +pkglibexec_SCRIPTS += src/libostree/s390x-se-luks-gencpio diff --git a/src/libostree/ostree-bootloader-zipl.c b/src/libostree/ostree-bootloader-zipl.c index 7358671b..14c2762e 100644 --- a/src/libostree/ostree-bootloader-zipl.c +++ b/src/libostree/ostree-bootloader-zipl.c @@ -27,6 +27,9 @@ #define SECURE_EXECUTION_BOOT_IMAGE "/boot/sd-boot" #define SECURE_EXECUTION_HOSTKEY_PATH "/etc/se-hostkeys/" #define SECURE_EXECUTION_HOSTKEY_PREFIX "ibm-z-hostkey" +#define SECURE_EXECUTION_LUKS_ROOT_KEY "/etc/luks/root" +#define SECURE_EXECUTION_LUKS_CONFIG "/etc/crypttab" +#define SECURE_EXECUTION_RAMDISK_TOOL PKGLIBEXECDIR "/s390x-se-luks-gencpio" /* This is specific to zipl today, but in the future we could also * use it for the grub2-mkconfig case. @@ -147,6 +150,37 @@ _ostree_secure_execution_get_bls_config (OstreeBootloaderZipl *self, return TRUE; } +static gboolean +_ostree_secure_execution_luks_key_exists (void) +{ + return (access(SECURE_EXECUTION_LUKS_ROOT_KEY, F_OK) == 0 && + access(SECURE_EXECUTION_LUKS_CONFIG, F_OK) == 0); +} + +static gboolean +_ostree_secure_execution_enable_luks(const gchar *oldramfs, + const gchar *newramfs, + GError **error) +{ + const char *const argv[] = {SECURE_EXECUTION_RAMDISK_TOOL, oldramfs, newramfs, NULL}; + g_autofree gchar *out = NULL; + g_autofree gchar *err = NULL; + int status = 0; + if (!g_spawn_sync (NULL, (char**)argv, NULL, G_SPAWN_SEARCH_PATH, + NULL, NULL, &out, &err, &status, error)) + return glnx_prefix_error(error, "s390x SE: spawning %s", SECURE_EXECUTION_RAMDISK_TOOL); + + if (!g_spawn_check_exit_status (status, error)) + { + g_printerr("s390x SE: `%s` stdout: %s\n", SECURE_EXECUTION_RAMDISK_TOOL, out); + g_printerr("s390x SE: `%s` stderr: %s\n", SECURE_EXECUTION_RAMDISK_TOOL, err); + return glnx_prefix_error(error, "s390x SE: `%s` failed", SECURE_EXECUTION_RAMDISK_TOOL); + } + + sd_journal_print(LOG_INFO, "s390x SE: luks key added to initrd"); + return TRUE; +} + static gboolean _ostree_secure_execution_generate_sdboot (gchar *vmlinuz, gchar *initramfs, @@ -169,12 +203,24 @@ _ostree_secure_execution_generate_sdboot (gchar *vmlinuz, return glnx_throw_errno_prefix (error, "s390x SE: writting cmdline file"); g_autofree gchar *cmdline_filename = g_strdup_printf ("/proc/%d/fd/%d", self, cmdline.fd); + // Copy initramfs to temp file and embed LUKS key and config into it + g_auto(GLnxTmpfile) ramdisk = { 0, }; + g_autofree gchar *ramdisk_filename = NULL; + if (_ostree_secure_execution_luks_key_exists ()) + { + if (!glnx_open_anonymous_tmpfile (O_RDWR | O_CLOEXEC, &ramdisk, error)) + return glnx_prefix_error(error, "s390x SE: creating new ramdisk"); + ramdisk_filename = g_strdup_printf ("/proc/%d/fd/%d", self, ramdisk.fd); + if (!_ostree_secure_execution_enable_luks (initramfs, ramdisk_filename, error)) + return FALSE; + } + g_autoptr(GPtrArray) argv = g_ptr_array_new (); g_ptr_array_add (argv, "genprotimg"); g_ptr_array_add (argv, "-i"); g_ptr_array_add (argv, vmlinuz); g_ptr_array_add (argv, "-r"); - g_ptr_array_add (argv, initramfs); + g_ptr_array_add (argv, (ramdisk_filename == NULL) ? initramfs: ramdisk_filename); g_ptr_array_add (argv, "-p"); g_ptr_array_add (argv, cmdline_filename); for (guint i = 0; i < keys->len; ++i) @@ -191,7 +237,7 @@ _ostree_secure_execution_generate_sdboot (gchar *vmlinuz, gint status = 0; if (!g_spawn_sync (NULL, (char**)argv->pdata, NULL, G_SPAWN_SEARCH_PATH, - NULL, NULL, NULL, NULL, &status, error)) + NULL, NULL, NULL, NULL, &status, error)) return glnx_prefix_error(error, "s390x SE: spawning genprotimg"); if (!g_spawn_check_exit_status (status, error)) diff --git a/src/libostree/s390x-se-luks-gencpio b/src/libostree/s390x-se-luks-gencpio new file mode 100755 index 00000000..f0ad24eb --- /dev/null +++ b/src/libostree/s390x-se-luks-gencpio @@ -0,0 +1,22 @@ + #!/usr/bin/bash + # This script creates new initramdisk with LUKS config within +set -euo pipefail + +old_initrd=$1 +new_initrd=$2 + +# Unpacking existing initramdisk +workdir=$(mktemp -d -p /tmp se-initramfs-XXXXXX) +cd ${workdir} +gzip -cd ${old_initrd} | cpio -imd --quiet + +# Adding LUKS root key and crypttab config +mkdir -p etc/luks +cp -f /etc/luks/root etc/luks/ +cp -f /etc/crypttab etc/ + +# Creating new initramdisk image +find . | cpio --quiet -H newc -o | gzip -9 -n >> ${new_initrd} + +# Cleanup +rm -rf ${workdir}