/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include #include #include #include #include #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 "systemd-veritysetup@root.service" static const char *arg_dest = NULL; static bool arg_enabled = true; static char *arg_root_hash = NULL; static char *arg_data_what = NULL; static char *arg_hash_what = NULL; STATIC_DESTRUCTOR_REGISTER(arg_root_hash, freep); STATIC_DESTRUCTOR_REGISTER(arg_data_what, freep); STATIC_DESTRUCTOR_REGISTER(arg_hash_what, freep); static int create_device(void) { _cleanup_free_ char *u = NULL, *v = NULL, *d = NULL, *e = NULL, *u_escaped = NULL, *v_escaped = NULL, *root_hash_escaped = NULL; _cleanup_fclose_ FILE *f = NULL; const char *to; int r; /* If all three pieces of information are missing, then verity is turned off */ if (!arg_root_hash && !arg_data_what && !arg_hash_what) return 0; /* if one of them is missing however, the data is simply incomplete and this is an error */ if (!arg_root_hash) log_error("Verity information incomplete, root hash unspecified."); if (!arg_data_what) log_error("Verity information incomplete, root data device unspecified."); if (!arg_hash_what) log_error("Verity information incomplete, root hash device unspecified."); if (!arg_root_hash || !arg_data_what || !arg_hash_what) return -EINVAL; log_debug("Using root verity data device %s,\n" " hash device %s,\n" " and root hash %s.", arg_data_what, arg_hash_what, arg_root_hash); u = fstab_node_to_udev_node(arg_data_what); if (!u) return log_oom(); v = fstab_node_to_udev_node(arg_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"); root_hash_escaped = specifier_escape(arg_root_hash); if (!root_hash_escaped) return log_oom(); r = generator_open_unit_file(arg_dest, NULL, SYSTEMD_VERITYSETUP_SERVICE, &f); if (r < 0) return r; fprintf(f, "[Unit]\n" "Description=Integrity 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=cryptsetup-pre.target %s %s\n" "Before=cryptsetup.target umount.target\n" "\n[Service]\n" "Type=oneshot\n" "RemainAfterExit=yes\n" "ExecStart=" ROOTLIBEXECDIR "/systemd-veritysetup attach root '%s' '%s' '%s'\n" "ExecStop=" ROOTLIBEXECDIR "/systemd-veritysetup detach root\n", d, e, d, e, u_escaped, v_escaped, root_hash_escaped); r = fflush_and_check(f); if (r < 0) return log_error_errno(r, "Failed to write file unit "SYSTEMD_VERITYSETUP_SERVICE": %m"); to = strjoina(arg_dest, "/cryptsetup.target.requires/" SYSTEMD_VERITYSETUP_SERVICE); (void) mkdir_parents(to, 0755); if (symlink("../" SYSTEMD_VERITYSETUP_SERVICE, to) < 0) return log_error_errno(errno, "Failed to create symlink %s: %m", to); return 0; } 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 (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_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_hash_what, value); if (r < 0) return log_oom(); } return 0; } static int determine_devices(void) { _cleanup_free_ void *m = NULL; sd_id128_t root_uuid, verity_uuid; char ids[ID128_UUID_STRING_MAX]; size_t l; int r; /* Try to automatically derive the root data and hash device paths from the root hash */ if (!arg_root_hash) return 0; if (arg_data_what && arg_hash_what) return 0; r = unhexmem(arg_root_hash, strlen(arg_root_hash), &m, &l); if (r < 0) return log_error_errno(r, "Failed to parse root hash: %s", arg_root_hash); if (l < sizeof(sd_id128_t)) { log_debug("Root hash is shorter than 128 bits (32 characters), ignoring for discovering verity partition."); return 0; } if (!arg_data_what) { memcpy(&root_uuid, m, sizeof(root_uuid)); arg_data_what = path_join("/dev/disk/by-partuuid", id128_to_uuid_string(root_uuid, ids)); if (!arg_data_what) return log_oom(); } if (!arg_hash_what) { memcpy(&verity_uuid, (uint8_t*) m + l - sizeof(verity_uuid), sizeof(verity_uuid)); arg_hash_what = path_join("/dev/disk/by-partuuid", id128_to_uuid_string(verity_uuid, ids)); if (!arg_hash_what) return log_oom(); } return 1; } static int run(const char *dest, const char *dest_early, const char *dest_late) { int r; assert_se(arg_dest = dest); 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"); /* For now we only support the root device on verity. Later on we might want to add support for /etc/veritytab * or similar to define additional mappings */ if (!arg_enabled) return 0; r = determine_devices(); if (r < 0) return r; return create_device(); } DEFINE_MAIN_GENERATOR_FUNCTION(run);