| /* SPDX-License-Identifier: LGPL-2.1+ */ |
| /*** |
| ***/ |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <unistd.h> |
| |
| #include "sd-id128.h" |
| |
| #include "alloc-util.h" |
| #include "fd-util.h" |
| #include "hexdecoct.h" |
| #include "id128-util.h" |
| #include "io-util.h" |
| #include "khash.h" |
| #include "macro.h" |
| #include "missing.h" |
| #include "random-util.h" |
| #include "user-util.h" |
| #include "util.h" |
| |
| _public_ char *sd_id128_to_string(sd_id128_t id, char s[SD_ID128_STRING_MAX]) { |
| unsigned n; |
| |
| assert_return(s, NULL); |
| |
| for (n = 0; n < 16; n++) { |
| s[n*2] = hexchar(id.bytes[n] >> 4); |
| s[n*2+1] = hexchar(id.bytes[n] & 0xF); |
| } |
| |
| s[32] = 0; |
| |
| return s; |
| } |
| |
| _public_ int sd_id128_from_string(const char s[], sd_id128_t *ret) { |
| unsigned n, i; |
| sd_id128_t t; |
| bool is_guid = false; |
| |
| assert_return(s, -EINVAL); |
| |
| for (n = 0, i = 0; n < 16;) { |
| int a, b; |
| |
| if (s[i] == '-') { |
| /* Is this a GUID? Then be nice, and skip over |
| * the dashes */ |
| |
| if (i == 8) |
| is_guid = true; |
| else if (IN_SET(i, 13, 18, 23)) { |
| if (!is_guid) |
| return -EINVAL; |
| } else |
| return -EINVAL; |
| |
| i++; |
| continue; |
| } |
| |
| a = unhexchar(s[i++]); |
| if (a < 0) |
| return -EINVAL; |
| |
| b = unhexchar(s[i++]); |
| if (b < 0) |
| return -EINVAL; |
| |
| t.bytes[n++] = (a << 4) | b; |
| } |
| |
| if (i != (is_guid ? 36 : 32)) |
| return -EINVAL; |
| |
| if (s[i] != 0) |
| return -EINVAL; |
| |
| if (ret) |
| *ret = t; |
| return 0; |
| } |
| |
| _public_ int sd_id128_get_machine(sd_id128_t *ret) { |
| static thread_local sd_id128_t saved_machine_id = {}; |
| int r; |
| |
| assert_return(ret, -EINVAL); |
| |
| if (sd_id128_is_null(saved_machine_id)) { |
| r = id128_read("/etc/machine-id", ID128_PLAIN, &saved_machine_id); |
| if (r < 0) |
| return r; |
| |
| if (sd_id128_is_null(saved_machine_id)) |
| return -ENOMEDIUM; |
| } |
| |
| *ret = saved_machine_id; |
| return 0; |
| } |
| |
| _public_ int sd_id128_get_boot(sd_id128_t *ret) { |
| static thread_local sd_id128_t saved_boot_id = {}; |
| int r; |
| |
| assert_return(ret, -EINVAL); |
| |
| if (sd_id128_is_null(saved_boot_id)) { |
| r = id128_read("/proc/sys/kernel/random/boot_id", ID128_UUID, &saved_boot_id); |
| if (r < 0) |
| return r; |
| } |
| |
| *ret = saved_boot_id; |
| return 0; |
| } |
| |
| static int get_invocation_from_keyring(sd_id128_t *ret) { |
| |
| _cleanup_free_ char *description = NULL; |
| char *d, *p, *g, *u, *e; |
| unsigned long perms; |
| key_serial_t key; |
| size_t sz = 256; |
| uid_t uid; |
| gid_t gid; |
| int r, c; |
| |
| #define MAX_PERMS ((unsigned long) (KEY_POS_VIEW|KEY_POS_READ|KEY_POS_SEARCH| \ |
| KEY_USR_VIEW|KEY_USR_READ|KEY_USR_SEARCH)) |
| |
| assert(ret); |
| |
| key = request_key("user", "invocation_id", NULL, 0); |
| if (key == -1) { |
| /* Keyring support not available? No invocation key stored? */ |
| if (IN_SET(errno, ENOSYS, ENOKEY)) |
| return 0; |
| |
| return -errno; |
| } |
| |
| for (;;) { |
| description = new(char, sz); |
| if (!description) |
| return -ENOMEM; |
| |
| c = keyctl(KEYCTL_DESCRIBE, key, (unsigned long) description, sz, 0); |
| if (c < 0) |
| return -errno; |
| |
| if ((size_t) c <= sz) |
| break; |
| |
| sz = c; |
| free(description); |
| } |
| |
| /* The kernel returns a final NUL in the string, verify that. */ |
| assert(description[c-1] == 0); |
| |
| /* Chop off the final description string */ |
| d = strrchr(description, ';'); |
| if (!d) |
| return -EIO; |
| *d = 0; |
| |
| /* Look for the permissions */ |
| p = strrchr(description, ';'); |
| if (!p) |
| return -EIO; |
| |
| errno = 0; |
| perms = strtoul(p + 1, &e, 16); |
| if (errno > 0) |
| return -errno; |
| if (e == p + 1) /* Read at least one character */ |
| return -EIO; |
| if (e != d) /* Must reached the end */ |
| return -EIO; |
| |
| if ((perms & ~MAX_PERMS) != 0) |
| return -EPERM; |
| |
| *p = 0; |
| |
| /* Look for the group ID */ |
| g = strrchr(description, ';'); |
| if (!g) |
| return -EIO; |
| r = parse_gid(g + 1, &gid); |
| if (r < 0) |
| return r; |
| if (gid != 0) |
| return -EPERM; |
| *g = 0; |
| |
| /* Look for the user ID */ |
| u = strrchr(description, ';'); |
| if (!u) |
| return -EIO; |
| r = parse_uid(u + 1, &uid); |
| if (r < 0) |
| return r; |
| if (uid != 0) |
| return -EPERM; |
| |
| c = keyctl(KEYCTL_READ, key, (unsigned long) ret, sizeof(sd_id128_t), 0); |
| if (c < 0) |
| return -errno; |
| if (c != sizeof(sd_id128_t)) |
| return -EIO; |
| |
| return 1; |
| } |
| |
| _public_ int sd_id128_get_invocation(sd_id128_t *ret) { |
| static thread_local sd_id128_t saved_invocation_id = {}; |
| int r; |
| |
| assert_return(ret, -EINVAL); |
| |
| if (sd_id128_is_null(saved_invocation_id)) { |
| |
| /* We first try to read the invocation ID from the kernel keyring. This has the benefit that it is not |
| * fakeable by unprivileged code. If the information is not available in the keyring, we use |
| * $INVOCATION_ID but ignore the data if our process was called by less privileged code |
| * (i.e. secure_getenv() instead of getenv()). |
| * |
| * The kernel keyring is only relevant for system services (as for user services we don't store the |
| * invocation ID in the keyring, as there'd be no trust benefit in that). The environment variable is |
| * primarily relevant for user services, and sufficiently safe as no privilege boundary is involved. */ |
| |
| r = get_invocation_from_keyring(&saved_invocation_id); |
| if (r < 0) |
| return r; |
| |
| if (r == 0) { |
| const char *e; |
| |
| e = secure_getenv("INVOCATION_ID"); |
| if (!e) |
| return -ENXIO; |
| |
| r = sd_id128_from_string(e, &saved_invocation_id); |
| if (r < 0) |
| return r; |
| } |
| } |
| |
| *ret = saved_invocation_id; |
| return 0; |
| } |
| |
| static sd_id128_t make_v4_uuid(sd_id128_t id) { |
| /* Stolen from generate_random_uuid() of drivers/char/random.c |
| * in the kernel sources */ |
| |
| /* Set UUID version to 4 --- truly random generation */ |
| id.bytes[6] = (id.bytes[6] & 0x0F) | 0x40; |
| |
| /* Set the UUID variant to DCE */ |
| id.bytes[8] = (id.bytes[8] & 0x3F) | 0x80; |
| |
| return id; |
| } |
| |
| _public_ int sd_id128_randomize(sd_id128_t *ret) { |
| sd_id128_t t; |
| int r; |
| |
| assert_return(ret, -EINVAL); |
| |
| r = acquire_random_bytes(&t, sizeof t, true); |
| if (r < 0) |
| return r; |
| |
| /* Turn this into a valid v4 UUID, to be nice. Note that we |
| * only guarantee this for newly generated UUIDs, not for |
| * pre-existing ones. */ |
| |
| *ret = make_v4_uuid(t); |
| return 0; |
| } |
| |
| _public_ int sd_id128_get_machine_app_specific(sd_id128_t app_id, sd_id128_t *ret) { |
| _cleanup_(khash_unrefp) khash *h = NULL; |
| sd_id128_t m, result; |
| const void *p; |
| int r; |
| |
| assert_return(ret, -EINVAL); |
| |
| r = sd_id128_get_machine(&m); |
| if (r < 0) |
| return r; |
| |
| r = khash_new_with_key(&h, "hmac(sha256)", &m, sizeof(m)); |
| if (r < 0) |
| return r; |
| |
| r = khash_put(h, &app_id, sizeof(app_id)); |
| if (r < 0) |
| return r; |
| |
| r = khash_digest_data(h, &p); |
| if (r < 0) |
| return r; |
| |
| /* We chop off the trailing 16 bytes */ |
| memcpy(&result, p, MIN(khash_get_size(h), sizeof(result))); |
| |
| *ret = make_v4_uuid(result); |
| return 0; |
| } |