[thirdparty/systemd.git] / src / veritysetup / veritysetup-generator.c

/* 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 "main-func.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 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[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;
}

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);
Commit	Line	Data
53e1b683	1	/* SPDX-License-Identifier: LGPL-2.1+ */
2f3dfc6f	2
dccca82b	3	#include <errno.h>
2f3dfc6f LP	4	#include <stdbool.h>
	5	#include <stdlib.h>
	6	#include <sys/stat.h>
	7	#include <unistd.h>
	8
	9	#include "alloc-util.h"
	10	#include "fd-util.h"
	11	#include "fileio.h"
	12	#include "fstab-util.h"
fb883e75	13	#include "generator.h"
2f3dfc6f LP	14	#include "hexdecoct.h"
2f3dfc6f LP	15	#include "id128-util.h"
d850ad9a	16	#include "main-func.h"
2f3dfc6f LP	17	#include "mkdir.h"
	18	#include "parse-util.h"
	19	#include "proc-cmdline.h"
98bad05e	20	#include "specifier.h"
2f3dfc6f LP	21	#include "string-util.h"
	22	#include "unit-name.h"
	23
fb883e75 ZJS	24	#define SYSTEMD_VERITYSETUP_SERVICE "systemd-veritysetup@root.service"
fb883e75 ZJS	25
2cb52121	26	static const char *arg_dest = NULL;
2f3dfc6f LP	27	static bool arg_enabled = true;
	28	static char *arg_root_hash = NULL;
	29	static char *arg_data_what = NULL;
	30	static char *arg_hash_what = NULL;
	31
d850ad9a YW	32	STATIC_DESTRUCTOR_REGISTER(arg_root_hash, freep);
	33	STATIC_DESTRUCTOR_REGISTER(arg_data_what, freep);
	34	STATIC_DESTRUCTOR_REGISTER(arg_hash_what, freep);
	35
2f3dfc6f	36	static int create_device(void) {
98bad05e	37	_cleanup_free_ char u = NULL, v = NULL, d = NULL, e = NULL, u_escaped = NULL, v_escaped = NULL, *root_hash_escaped = NULL;
2f3dfc6f	38	_cleanup_fclose_ FILE *f = NULL;
fb883e75	39	const char *to;
2f3dfc6f LP	40	int r;
	41
	42	/* If all three pieces of information are missing, then verity is turned off */
	43	if (!arg_root_hash && !arg_data_what && !arg_hash_what)
	44	return 0;
	45
	46	/* if one of them is missing however, the data is simply incomplete and this is an error */
	47	if (!arg_root_hash)
	48	log_error("Verity information incomplete, root hash unspecified.");
	49	if (!arg_data_what)
	50	log_error("Verity information incomplete, root data device unspecified.");
	51	if (!arg_hash_what)
	52	log_error("Verity information incomplete, root hash device unspecified.");
	53
	54	if (!arg_root_hash \|\| !arg_data_what \|\| !arg_hash_what)
	55	return -EINVAL;
	56
	57	log_debug("Using root verity data device %s,\n"
	58	" hash device %s,\n"
	59	" and root hash %s.", arg_data_what, arg_hash_what, arg_root_hash);
	60
2f3dfc6f LP	61	u = fstab_node_to_udev_node(arg_data_what);
	62	if (!u)
	63	return log_oom();
	64	v = fstab_node_to_udev_node(arg_hash_what);
	65	if (!v)
	66	return log_oom();
	67
98bad05e LP	68	u_escaped = specifier_escape(u);
	69	if (!u_escaped)
	70	return log_oom();
	71	v_escaped = specifier_escape(v);
	72	if (!v_escaped)
	73	return log_oom();
	74
2f3dfc6f LP	75	r = unit_name_from_path(u, ".device", &d);
2f3dfc6f LP	76	if (r < 0)
1a012455	77	return log_error_errno(r, "Failed to generate unit name: %m");
2f3dfc6f LP	78	r = unit_name_from_path(v, ".device", &e);
2f3dfc6f LP	79	if (r < 0)
1a012455	80	return log_error_errno(r, "Failed to generate unit name: %m");
2f3dfc6f	81
98bad05e LP	82	root_hash_escaped = specifier_escape(arg_root_hash);
	83	if (!root_hash_escaped)
	84	return log_oom();
	85
fb883e75 ZJS	86	r = generator_open_unit_file(arg_dest, NULL, SYSTEMD_VERITYSETUP_SERVICE, &f);
	87	if (r < 0)
	88	return r;
2f3dfc6f LP	89
2f3dfc6f LP	90	fprintf(f,
2f3dfc6f LP	91	"[Unit]\n"
	92	"Description=Integrity Protection Setup for %%I\n"
	93	"Documentation=man:systemd-veritysetup-generator(8) man:systemd-veritysetup@.service(8)\n"
	94	"SourcePath=/proc/cmdline\n"
	95	"DefaultDependencies=no\n"
	96	"Conflicts=umount.target\n"
	97	"BindsTo=%s %s\n"
	98	"IgnoreOnIsolate=true\n"
	99	"After=cryptsetup-pre.target %s %s\n"
	100	"Before=cryptsetup.target umount.target\n"
	101	"\n[Service]\n"
	102	"Type=oneshot\n"
	103	"RemainAfterExit=yes\n"
	104	"ExecStart=" ROOTLIBEXECDIR "/systemd-veritysetup attach root '%s' '%s' '%s'\n"
	105	"ExecStop=" ROOTLIBEXECDIR "/systemd-veritysetup detach root\n",
	106	d, e,
	107	d, e,
98bad05e	108	u_escaped, v_escaped, root_hash_escaped);
2f3dfc6f LP	109
	110	r = fflush_and_check(f);
	111	if (r < 0)
fb883e75	112	return log_error_errno(r, "Failed to write file unit "SYSTEMD_VERITYSETUP_SERVICE": %m");
2f3dfc6f	113
fb883e75	114	to = strjoina(arg_dest, "/cryptsetup.target.requires/" SYSTEMD_VERITYSETUP_SERVICE);
2f3dfc6f LP	115
2f3dfc6f LP	116	(void) mkdir_parents(to, 0755);
fb883e75	117	if (symlink("../" SYSTEMD_VERITYSETUP_SERVICE, to) < 0)
2f3dfc6f LP	118	return log_error_errno(errno, "Failed to create symlink %s: %m", to);
	119
	120	return 0;
	121	}
	122
	123	static int parse_proc_cmdline_item(const char key, const char value, void *data) {
	124	int r;
	125
ad0cdb6b	126	if (proc_cmdline_key_streq(key, "systemd.verity")) {
2f3dfc6f LP	127
	128	r = value ? parse_boolean(value) : 1;
	129	if (r < 0)
	130	log_warning("Failed to parse verity= kernel command line switch %s. Ignoring.", value);
	131	else
	132	arg_enabled = r;
	133
ad0cdb6b	134	} else if (proc_cmdline_key_streq(key, "roothash")) {
2f3dfc6f LP	135
	136	if (proc_cmdline_value_missing(key, value))
	137	return 0;
	138
	139	r = free_and_strdup(&arg_root_hash, value);
	140	if (r < 0)
	141	return log_oom();
	142
ad0cdb6b	143	} else if (proc_cmdline_key_streq(key, "systemd.verity_root_data")) {
2f3dfc6f LP	144
	145	if (proc_cmdline_value_missing(key, value))
	146	return 0;
	147
	148	r = free_and_strdup(&arg_data_what, value);
	149	if (r < 0)
	150	return log_oom();
	151
ad0cdb6b	152	} else if (proc_cmdline_key_streq(key, "systemd.verity_root_hash")) {
2f3dfc6f LP	153
	154	if (proc_cmdline_value_missing(key, value))
	155	return 0;
	156
	157	r = free_and_strdup(&arg_hash_what, value);
	158	if (r < 0)
	159	return log_oom();
	160	}
	161
	162	return 0;
	163	}
	164
	165	static int determine_devices(void) {
	166	_cleanup_free_ void *m = NULL;
	167	sd_id128_t root_uuid, verity_uuid;
	168	char ids[37];
	169	size_t l;
	170	int r;
	171
	172	/* Try to automatically derive the root data and hash device paths from the root hash */
	173
	174	if (!arg_root_hash)
	175	return 0;
	176
	177	if (arg_data_what && arg_hash_what)
	178	return 0;
	179
	180	r = unhexmem(arg_root_hash, strlen(arg_root_hash), &m, &l);
	181	if (r < 0)
	182	return log_error_errno(r, "Failed to parse root hash: %s", arg_root_hash);
	183	if (l < sizeof(sd_id128_t)) {
	184	log_debug("Root hash is shorter than 128 bits (32 characters), ignoring for discovering verity partition.");
	185	return 0;
	186	}
	187
	188	if (!arg_data_what) {
	189	memcpy(&root_uuid, m, sizeof(root_uuid));
	190
	191	arg_data_what = strjoin("/dev/disk/by-partuuid/", id128_to_uuid_string(root_uuid, ids));
	192	if (!arg_data_what)
	193	return log_oom();
	194	}
	195
	196	if (!arg_hash_what) {
	197	memcpy(&verity_uuid, (uint8_t*) m + l - sizeof(verity_uuid), sizeof(verity_uuid));
	198
	199	arg_hash_what = strjoin("/dev/disk/by-partuuid/", id128_to_uuid_string(verity_uuid, ids));
	200	if (!arg_hash_what)
	201	return log_oom();
	202	}
	203
	204	return 1;
	205	}
	206
7a44c7e3	207	static int run(const char dest, const char dest_early, const char *dest_late) {
2f3dfc6f LP	208	int r;
2f3dfc6f LP	209
7a44c7e3	210	assert_se(arg_dest = dest);
2f3dfc6f	211
2f3dfc6f	212	r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, PROC_CMDLINE_STRIP_RD_PREFIX);
d850ad9a YW	213	if (r < 0)
d850ad9a YW	214	return log_warning_errno(r, "Failed to parse kernel command line: %m");
2f3dfc6f LP	215
	216	/* For now we only support the root device on verity. Later on we might want to add support for /etc/veritytab
	217	* or similar to define additional mappings */
	218
d850ad9a YW	219	if (!arg_enabled)
d850ad9a YW	220	return 0;
2f3dfc6f LP	221
	222	r = determine_devices();
	223	if (r < 0)
d850ad9a	224	return r;
2f3dfc6f	225
7a44c7e3	226	return create_device();
2f3dfc6f	227	}
d850ad9a	228
7a44c7e3	229	DEFINE_MAIN_GENERATOR_FUNCTION(run);