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-rw-r--r--src/libsystemd/sd-id128/sd-id128.c340
1 files changed, 340 insertions, 0 deletions
diff --git a/src/libsystemd/sd-id128/sd-id128.c b/src/libsystemd/sd-id128/sd-id128.c
new file mode 100644
index 0000000..e72af15
--- /dev/null
+++ b/src/libsystemd/sd-id128/sd-id128.c
@@ -0,0 +1,340 @@
+/* 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_ARRAY_STATIC 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);
+
+ /* We allow usage if x86-64 RDRAND here. It might not be trusted enough for keeping secrets, but it should be
+ * fine for UUIDS. */
+ r = genuine_random_bytes(&t, sizeof t, RANDOM_ALLOW_RDRAND);
+ 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;
+}
+
+static int get_app_specific(sd_id128_t base, sd_id128_t app_id, sd_id128_t *ret) {
+ _cleanup_(khash_unrefp) khash *h = NULL;
+ sd_id128_t result;
+ const void *p;
+ int r;
+
+ assert(ret);
+
+ r = khash_new_with_key(&h, "hmac(sha256)", &base, sizeof(base));
+ 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;
+}
+
+_public_ int sd_id128_get_machine_app_specific(sd_id128_t app_id, sd_id128_t *ret) {
+ sd_id128_t id;
+ int r;
+
+ assert_return(ret, -EINVAL);
+
+ r = sd_id128_get_machine(&id);
+ if (r < 0)
+ return r;
+
+ return get_app_specific(id, app_id, ret);
+}
+
+_public_ int sd_id128_get_boot_app_specific(sd_id128_t app_id, sd_id128_t *ret) {
+ sd_id128_t id;
+ int r;
+
+ assert_return(ret, -EINVAL);
+
+ r = sd_id128_get_boot(&id);
+ if (r < 0)
+ return r;
+
+ return get_app_specific(id, app_id, ret);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-27 06:39:32 +0000