| /* SPDX-License-Identifier: LGPL-2.1+ */ |
| |
| #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 "mkdir.h" |
| #include "parse-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 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 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 (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, "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 (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 (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[37]; |
| 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 = strjoin("/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 = strjoin("/dev/disk/by-partuuid/", id128_to_uuid_string(verity_uuid, ids)); |
| if (!arg_hash_what) |
| return log_oom(); |
| } |
| |
| return 1; |
| } |
| |
| int main(int argc, char *argv[]) { |
| int r; |
| |
| if (argc > 1 && argc != 4) { |
| log_error("This program takes three or no arguments."); |
| return EXIT_FAILURE; |
| } |
| |
| if (argc > 1) |
| arg_dest = argv[1]; |
| |
| log_set_prohibit_ipc(true); |
| log_set_target(LOG_TARGET_AUTO); |
| log_parse_environment(); |
| log_open(); |
| |
| umask(0022); |
| |
| r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, PROC_CMDLINE_STRIP_RD_PREFIX); |
| if (r < 0) { |
| log_warning_errno(r, "Failed to parse kernel command line: %m"); |
| goto finish; |
| } |
| |
| /* 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) { |
| r = 0; |
| goto finish; |
| } |
| |
| r = determine_devices(); |
| if (r < 0) |
| goto finish; |
| |
| r = create_device(); |
| if (r < 0) |
| goto finish; |
| |
| r = 0; |
| |
| finish: |
| free(arg_root_hash); |
| free(arg_data_what); |
| free(arg_hash_what); |
| |
| return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS; |
| } |