diff options
Diffstat (limited to 'src/veritysetup/veritysetup-generator.c')
| -rw-r--r-- | src/veritysetup/veritysetup-generator.c | 537 |
1 files changed, 537 insertions, 0 deletions
diff --git a/src/veritysetup/veritysetup-generator.c b/src/veritysetup/veritysetup-generator.c new file mode 100644 index 0000000..79152c4 --- /dev/null +++ b/src/veritysetup/veritysetup-generator.c @@ -0,0 +1,537 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <errno.h> +#include <stdbool.h> +#include <stdlib.h> +#include <sys/stat.h> +#include <unistd.h> + +#include "alloc-util.h" +#include "fd-util.h" +#include "fileio.h" +#include "fstab-util.h" +#include "generator.h" +#include "hexdecoct.h" +#include "id128-util.h" +#include "main-func.h" +#include "mkdir.h" +#include "parse-util.h" +#include "path-util.h" +#include "proc-cmdline.h" +#include "specifier.h" +#include "string-util.h" +#include "unit-name.h" + +#define SYSTEMD_VERITYSETUP_SERVICE_ROOT "systemd-veritysetup@root.service" +#define SYSTEMD_VERITYSETUP_SERVICE_USR "systemd-veritysetup@usr.service" + +static const char *arg_dest = NULL; +static bool arg_enabled = true; +static bool arg_read_veritytab = true; +static const char *arg_veritytab = NULL; +static char *arg_root_hash = NULL; +static char *arg_root_data_what = NULL; +static char *arg_root_hash_what = NULL; +static char *arg_root_options = NULL; +static char *arg_usr_hash = NULL; +static char *arg_usr_data_what = NULL; +static char *arg_usr_hash_what = NULL; +static char *arg_usr_options = NULL; + +STATIC_DESTRUCTOR_REGISTER(arg_root_hash, freep); +STATIC_DESTRUCTOR_REGISTER(arg_root_data_what, freep); +STATIC_DESTRUCTOR_REGISTER(arg_root_hash_what, freep); +STATIC_DESTRUCTOR_REGISTER(arg_root_options, freep); +STATIC_DESTRUCTOR_REGISTER(arg_usr_hash, freep); +STATIC_DESTRUCTOR_REGISTER(arg_usr_data_what, freep); +STATIC_DESTRUCTOR_REGISTER(arg_usr_hash_what, freep); +STATIC_DESTRUCTOR_REGISTER(arg_usr_options, freep); + +static int create_device( + const char *name, + const char *service, + const char *hash, + const char *data_what, + const char *hash_what, + const char *options) { + + _cleanup_free_ char *u = NULL, *v = NULL, *d = NULL, *e = NULL, *u_escaped = NULL, *v_escaped = NULL, + *hash_escaped = NULL, *options_escaped = NULL; + _cleanup_fclose_ FILE *f = NULL; + const char *to, *from; + int r; + + assert(name); + assert(service); + + /* If all three pieces of information are missing, then verity is turned off */ + if (!hash && !data_what && !hash_what) + return 0; + + /* if one of them is missing however, the data is simply incomplete and this is an error */ + if (!hash) + log_error("Verity information for %s incomplete, hash unspecified.", name); + if (!data_what) + log_error("Verity information for %s incomplete, data device unspecified.", name); + if (!hash_what) + log_error("Verity information for %s incomplete, hash device unspecified.", name); + + if (!hash || !data_what || !hash_what) + return -EINVAL; + + log_debug("Using %s verity data device %s, hash device %s, options %s, and hash %s.", name, data_what, hash_what, options, hash); + + u = fstab_node_to_udev_node(data_what); + if (!u) + return log_oom(); + v = fstab_node_to_udev_node(hash_what); + if (!v) + return log_oom(); + + u_escaped = specifier_escape(u); + if (!u_escaped) + return log_oom(); + v_escaped = specifier_escape(v); + if (!v_escaped) + return log_oom(); + + r = unit_name_from_path(u, ".device", &d); + if (r < 0) + return log_error_errno(r, "Failed to generate unit name: %m"); + r = unit_name_from_path(v, ".device", &e); + if (r < 0) + return log_error_errno(r, "Failed to generate unit name: %m"); + + options_escaped = specifier_escape(strempty(options)); + if (!options_escaped) + return log_oom(); + + hash_escaped = specifier_escape(hash); + if (!hash_escaped) + return log_oom(); + + r = generator_open_unit_file(arg_dest, NULL, service, &f); + if (r < 0) + return r; + + fprintf(f, + "[Unit]\n" + "Description=Verity Protection Setup for %%I\n" + "Documentation=man:systemd-veritysetup-generator(8) man:systemd-veritysetup@.service(8)\n" + "SourcePath=/proc/cmdline\n" + "DefaultDependencies=no\n" + "Conflicts=umount.target\n" + "BindsTo=%s %s\n" + "IgnoreOnIsolate=true\n" + "After=veritysetup-pre.target systemd-udevd-kernel.socket %s %s\n" + "Before=veritysetup.target umount.target\n" + "\n[Service]\n" + "Type=oneshot\n" + "RemainAfterExit=yes\n" + "ExecStart=" ROOTLIBEXECDIR "/systemd-veritysetup attach '%s' '%s' '%s' '%s' '%s'\n" + "ExecStop=" ROOTLIBEXECDIR "/systemd-veritysetup detach '%s' \n", + d, e, + d, e, + name, u_escaped, v_escaped, hash_escaped, options_escaped, + name); + + r = fflush_and_check(f); + if (r < 0) + return log_error_errno(r, "Failed to write file unit %s: %m", service); + + to = strjoina(arg_dest, "/veritysetup.target.requires/", service); + from = strjoina("../", service); + + (void) mkdir_parents(to, 0755); + if (symlink(from, to) < 0) + return log_error_errno(errno, "Failed to create symlink %s: %m", to); + + return 0; +} + +static int create_root_device(void) { + return create_device("root", SYSTEMD_VERITYSETUP_SERVICE_ROOT, arg_root_hash, arg_root_data_what, arg_root_hash_what, arg_root_options); +} + +static int create_usr_device(void) { + return create_device("usr", SYSTEMD_VERITYSETUP_SERVICE_USR, arg_usr_hash, arg_usr_data_what, arg_usr_hash_what, arg_usr_options); +} + +static int parse_proc_cmdline_item(const char *key, const char *value, void *data) { + int r; + + if (proc_cmdline_key_streq(key, "systemd.verity")) { + + r = value ? parse_boolean(value) : 1; + if (r < 0) + log_warning("Failed to parse verity= kernel command line switch %s. Ignoring.", value); + else + arg_enabled = r; + + } else if (streq(key, "veritytab")) { + + r = value ? parse_boolean(value) : 1; + if (r < 0) + log_warning("Failed to parse veritytab= kernel command line switch %s. Ignoring.", value); + else + arg_read_veritytab = r; + + } else if (proc_cmdline_key_streq(key, "roothash")) { + + if (proc_cmdline_value_missing(key, value)) + return 0; + + r = free_and_strdup(&arg_root_hash, value); + if (r < 0) + return log_oom(); + + } else if (proc_cmdline_key_streq(key, "systemd.verity_root_data")) { + + if (proc_cmdline_value_missing(key, value)) + return 0; + + r = free_and_strdup(&arg_root_data_what, value); + if (r < 0) + return log_oom(); + + } else if (proc_cmdline_key_streq(key, "systemd.verity_root_hash")) { + + if (proc_cmdline_value_missing(key, value)) + return 0; + + r = free_and_strdup(&arg_root_hash_what, value); + if (r < 0) + return log_oom(); + + } else if (proc_cmdline_key_streq(key, "systemd.verity_root_options")) { + + if (proc_cmdline_value_missing(key, value)) + return 0; + + r = free_and_strdup(&arg_root_options, value); + if (r < 0) + return log_oom(); + + } else if (proc_cmdline_key_streq(key, "usrhash")) { + + if (proc_cmdline_value_missing(key, value)) + return 0; + + r = free_and_strdup(&arg_usr_hash, value); + if (r < 0) + return log_oom(); + + } else if (proc_cmdline_key_streq(key, "systemd.verity_usr_data")) { + + if (proc_cmdline_value_missing(key, value)) + return 0; + + r = free_and_strdup(&arg_usr_data_what, value); + if (r < 0) + return log_oom(); + + } else if (proc_cmdline_key_streq(key, "systemd.verity_usr_hash")) { + + if (proc_cmdline_value_missing(key, value)) + return 0; + + r = free_and_strdup(&arg_usr_hash_what, value); + if (r < 0) + return log_oom(); + + } else if (proc_cmdline_key_streq(key, "systemd.verity_usr_options")) { + + if (proc_cmdline_value_missing(key, value)) + return 0; + + r = free_and_strdup(&arg_usr_options, value); + if (r < 0) + return log_oom(); + + } + + return 0; +} + +static int determine_device( + const char *name, + const char *hash, + char **data_what, + char **hash_what) { + + sd_id128_t data_uuid, verity_uuid; + _cleanup_free_ void *m = NULL; + size_t l; + int r; + + assert(name); + assert(data_what); + assert(hash_what); + + if (!hash) + return 0; + + if (*data_what && *hash_what) + return 0; + + r = unhexmem(hash, strlen(hash), &m, &l); + if (r < 0) + return log_error_errno(r, "Failed to parse hash: %s", hash); + if (l < sizeof(sd_id128_t)) { + log_debug("Root hash for %s is shorter than 128 bits (32 characters), ignoring for discovering verity partition.", name); + return 0; + } + + if (!*data_what) { + memcpy(&data_uuid, m, sizeof(data_uuid)); + + *data_what = path_join("/dev/disk/by-partuuid", SD_ID128_TO_UUID_STRING(data_uuid)); + if (!*data_what) + return log_oom(); + } + + if (!*hash_what) { + memcpy(&verity_uuid, (uint8_t*) m + l - sizeof(verity_uuid), sizeof(verity_uuid)); + + *hash_what = path_join("/dev/disk/by-partuuid", SD_ID128_TO_UUID_STRING(verity_uuid)); + if (!*hash_what) + return log_oom(); + } + + log_info("Using data device %s and hash device %s for %s.", *data_what, *hash_what, name); + + return 1; +} + +static int determine_devices(void) { + int r; + + r = determine_device("root", arg_root_hash, &arg_root_data_what, &arg_root_hash_what); + if (r < 0) + return r; + + return determine_device("usr", arg_usr_hash, &arg_usr_data_what, &arg_usr_hash_what); +} + +static int create_disk( + const char *name, + const char *data_device, + const char *hash_device, + const char *roothash, + const char *options, + const char *source) { + + _cleanup_free_ char *n = NULL, *dd = NULL, *du = NULL, *hd = NULL, *hu = NULL, *e = NULL, + *du_escaped = NULL, *hu_escaped = NULL, *name_escaped = NULL; + _cleanup_fclose_ FILE *f = NULL; + const char *dmname; + bool noauto, nofail, netdev, attach_in_initrd; + int r; + + assert(name); + assert(data_device); + assert(hash_device); + assert(roothash); + + noauto = fstab_test_yes_no_option(options, "noauto\0" "auto\0"); + nofail = fstab_test_yes_no_option(options, "nofail\0" "fail\0"); + netdev = fstab_test_option(options, "_netdev\0"); + attach_in_initrd = fstab_test_option(options, "x-initrd.attach\0"); + + name_escaped = specifier_escape(name); + if (!name_escaped) + return log_oom(); + + e = unit_name_escape(name); + if (!e) + return log_oom(); + + du = fstab_node_to_udev_node(data_device); + if (!du) + return log_oom(); + + hu = fstab_node_to_udev_node(hash_device); + if (!hu) + return log_oom(); + + r = unit_name_build("systemd-veritysetup", e, ".service", &n); + if (r < 0) + return log_error_errno(r, "Failed to generate unit name: %m"); + + du_escaped = specifier_escape(du); + if (!du_escaped) + return log_oom(); + + hu_escaped = specifier_escape(hu); + if (!hu_escaped) + return log_oom(); + + r = unit_name_from_path(du, ".device", &dd); + if (r < 0) + return log_error_errno(r, "Failed to generate unit name: %m"); + + r = unit_name_from_path(hu, ".device", &hd); + if (r < 0) + return log_error_errno(r, "Failed to generate unit name: %m"); + + r = generator_open_unit_file(arg_dest, NULL, n, &f); + if (r < 0) + return r; + + r = generator_write_veritysetup_unit_section(f, source); + if (r < 0) + return r; + + if (netdev) + fprintf(f, "After=remote-fs-pre.target\n"); + + /* If initrd takes care of attaching the disk then it should also detach it during shutdown. */ + if (!attach_in_initrd) + fprintf(f, "Conflicts=umount.target\n"); + + if (!nofail) + fprintf(f, + "Before=%s\n", + netdev ? "remote-veritysetup.target" : "veritysetup.target"); + + if (path_startswith(du, "/dev/")) + fprintf(f, + "BindsTo=%s\n" + "After=%s\n" + "Before=umount.target\n", + dd, dd); + else + /* For loopback devices, add systemd-tmpfiles-setup-dev.service + dependency to ensure that loopback support is available in + the kernel (/dev/loop-control needs to exist) */ + fprintf(f, + "RequiresMountsFor=%s\n" + "Requires=systemd-tmpfiles-setup-dev.service\n" + "After=systemd-tmpfiles-setup-dev.service\n", + du_escaped); + + if (path_startswith(hu, "/dev/")) + fprintf(f, + "BindsTo=%s\n" + "After=%s\n" + "Before=umount.target\n", + hd, hd); + else + /* For loopback devices, add systemd-tmpfiles-setup-dev.service + dependency to ensure that loopback support is available in + the kernel (/dev/loop-control needs to exist) */ + fprintf(f, + "RequiresMountsFor=%s\n" + "Requires=systemd-tmpfiles-setup-dev.service\n" + "After=systemd-tmpfiles-setup-dev.service\n", + hu_escaped); + + r = generator_write_veritysetup_service_section(f, name, du, hu, roothash, options); + if (r < 0) + return r; + + r = fflush_and_check(f); + if (r < 0) + return log_error_errno(r, "Failed to write unit file %s: %m", n); + + if (!noauto) { + r = generator_add_symlink(arg_dest, + netdev ? "remote-veritysetup.target" : "veritysetup.target", + nofail ? "wants" : "requires", n); + if (r < 0) + return r; + } + + dmname = strjoina("dev-mapper-", e, ".device"); + return generator_add_symlink(arg_dest, dmname, "requires", n); +} + +static int add_veritytab_devices(void) { + _cleanup_fclose_ FILE *f = NULL; + unsigned veritytab_line = 0; + int r; + + if (!arg_read_veritytab) + return 0; + + r = fopen_unlocked(arg_veritytab, "re", &f); + if (r < 0) { + if (errno != ENOENT) + log_error_errno(errno, "Failed to open %s: %m", arg_veritytab); + return 0; + } + + for (;;) { + _cleanup_free_ char *line = NULL, *name = NULL, *data_device = NULL, *hash_device = NULL, + *roothash = NULL, *options = NULL; + char *l, *data_uuid, *hash_uuid; + + r = read_line(f, LONG_LINE_MAX, &line); + if (r < 0) + return log_error_errno(r, "Failed to read %s: %m", arg_veritytab); + if (r == 0) + break; + + veritytab_line++; + + l = strstrip(line); + if (IN_SET(l[0], 0, '#')) + continue; + + r = sscanf(l, "%ms %ms %ms %ms %ms", &name, &data_device, &hash_device, &roothash, &options); + if (!IN_SET(r, 4, 5)) { + log_error("Failed to parse %s:%u, ignoring.", arg_veritytab, veritytab_line); + continue; + } + + data_uuid = startswith(data_device, "UUID="); + if (!data_uuid) + data_uuid = path_startswith(data_device, "/dev/disk/by-uuid/"); + + hash_uuid = startswith(hash_device, "UUID="); + if (!hash_uuid) + hash_uuid = path_startswith(hash_device, "/dev/disk/by-uuid/"); + + r = create_disk(name, + data_device, + hash_device, + roothash, + options, + arg_veritytab); + if (r < 0) + return r; + } + + return 0; +} + +static int run(const char *dest, const char *dest_early, const char *dest_late) { + int r; + + assert_se(arg_dest = dest); + + arg_veritytab = getenv("SYSTEMD_VERITYTAB") ?: "/etc/veritytab"; + + r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, PROC_CMDLINE_STRIP_RD_PREFIX); + if (r < 0) + return log_warning_errno(r, "Failed to parse kernel command line: %m"); + + if (!arg_enabled) + return 0; + + r = add_veritytab_devices(); + if (r < 0) + return r; + + r = determine_devices(); + if (r < 0) + return r; + + r = create_root_device(); + if (r < 0) + return r; + + return create_usr_device(); +} + +DEFINE_MAIN_GENERATOR_FUNCTION(run); |