--- /dev/null
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#if HAVE_LIBFIDO2
+#include <fido.h>
+#endif
+
+#include "ask-password-api.h"
+#include "errno-util.h"
+#include "format-table.h"
+#include "hexdecoct.h"
+#include "homectl-fido2.h"
+#include "homectl-pkcs11.h"
+#include "libcrypt-util.h"
+#include "locale-util.h"
+#include "memory-util.h"
+#include "random-util.h"
+#include "strv.h"
+
+#if HAVE_LIBFIDO2
+static int add_fido2_credential_id(
+ JsonVariant **v,
+ const void *cid,
+ size_t cid_size) {
+
+ _cleanup_(json_variant_unrefp) JsonVariant *w = NULL;
+ _cleanup_strv_free_ char **l = NULL;
+ _cleanup_free_ char *escaped = NULL;
+ int r;
+
+ assert(v);
+ assert(cid);
+
+ r = base64mem(cid, cid_size, &escaped);
+ if (r < 0)
+ return log_error_errno(r, "Failed to base64 encode FIDO2 credential ID: %m");
+
+ w = json_variant_ref(json_variant_by_key(*v, "fido2HmacCredential"));
+ if (w) {
+ r = json_variant_strv(w, &l);
+ if (r < 0)
+ return log_error_errno(r, "Failed to parse FIDO2 credential ID list: %m");
+
+ if (strv_contains(l, escaped))
+ return 0;
+ }
+
+ r = strv_extend(&l, escaped);
+ if (r < 0)
+ return log_oom();
+
+ w = json_variant_unref(w);
+ r = json_variant_new_array_strv(&w, l);
+ if (r < 0)
+ return log_error_errno(r, "Failed to create FIDO2 credential ID JSON: %m");
+
+ r = json_variant_set_field(v, "fido2HmacCredential", w);
+ if (r < 0)
+ return log_error_errno(r, "Failed to update FIDO2 credential ID: %m");
+
+ return 0;
+}
+
+static int add_fido2_salt(
+ JsonVariant **v,
+ const void *cid,
+ size_t cid_size,
+ const void *fido2_salt,
+ size_t fido2_salt_size,
+ const void *secret,
+ size_t secret_size) {
+
+ _cleanup_(json_variant_unrefp) JsonVariant *l = NULL, *w = NULL, *e = NULL;
+ _cleanup_(erase_and_freep) char *base64_encoded = NULL;
+ _cleanup_free_ char *unix_salt = NULL;
+ struct crypt_data cd = {};
+ char *k;
+ int r;
+
+ r = make_salt(&unix_salt);
+ if (r < 0)
+ return log_error_errno(r, "Failed to generate salt: %m");
+
+ /* Before using UNIX hashing on the supplied key we base64 encode it, since crypt_r() and friends
+ * expect a NUL terminated string, and we use a binary key */
+ r = base64mem(secret, secret_size, &base64_encoded);
+ if (r < 0)
+ return log_error_errno(r, "Failed to base64 encode secret key: %m");
+
+ errno = 0;
+ k = crypt_r(base64_encoded, unix_salt, &cd);
+ if (!k)
+ return log_error_errno(errno_or_else(EINVAL), "Failed to UNIX hash secret key: %m");
+
+ r = json_build(&e, JSON_BUILD_OBJECT(
+ JSON_BUILD_PAIR("credential", JSON_BUILD_BASE64(cid, cid_size)),
+ JSON_BUILD_PAIR("salt", JSON_BUILD_BASE64(fido2_salt, fido2_salt_size)),
+ JSON_BUILD_PAIR("hashedPassword", JSON_BUILD_STRING(k))));
+ if (r < 0)
+ return log_error_errno(r, "Failed to build FIDO2 salt JSON key object: %m");
+
+ w = json_variant_ref(json_variant_by_key(*v, "privileged"));
+ l = json_variant_ref(json_variant_by_key(w, "fido2HmacSalt"));
+
+ r = json_variant_append_array(&l, e);
+ if (r < 0)
+ return log_error_errno(r, "Failed append FIDO2 salt: %m");
+
+ r = json_variant_set_field(&w, "fido2HmacSalt", l);
+ if (r < 0)
+ return log_error_errno(r, "Failed to set FDO2 salt: %m");
+
+ r = json_variant_set_field(v, "privileged", w);
+ if (r < 0)
+ return log_error_errno(r, "Failed to update privileged field: %m");
+
+ return 0;
+}
+#endif
+
+#define FIDO2_SALT_SIZE 32
+
+int identity_add_fido2_parameters(
+ JsonVariant **v,
+ const char *device) {
+
+#if HAVE_LIBFIDO2
+ _cleanup_(fido_cbor_info_free) fido_cbor_info_t *di = NULL;
+ _cleanup_(fido_assert_free) fido_assert_t *a = NULL;
+ _cleanup_(erase_and_freep) char *used_pin = NULL;
+ _cleanup_(fido_cred_free) fido_cred_t *c = NULL;
+ _cleanup_(fido_dev_free) fido_dev_t *d = NULL;
+ _cleanup_(erase_and_freep) void *salt = NULL;
+ JsonVariant *un, *realm, *rn;
+ bool found_extension = false;
+ const void *cid, *secret;
+ const char *fido_un;
+ size_t n, cid_size, secret_size;
+ char **e;
+ int r;
+
+ /* Construction is like this: we generate a salt of 32 bytes. We then ask the FIDO2 device to
+ * HMAC-SHA256 it for us with its internal key. The result is the key used by LUKS and account
+ * authentication. LUKS and UNIX password auth all do their own salting before hashing, so that FIDO2
+ * device never sees the volume key.
+ *
+ * S = HMAC-SHA256(I, D)
+ *
+ * with: S → LUKS/account authentication key (never stored)
+ * I → internal key on FIDO2 device (stored in the FIDO2 device)
+ * D → salt we generate here (stored in the privileged part of the JSON record)
+ *
+ */
+
+ assert(v);
+ assert(device);
+
+ salt = malloc(FIDO2_SALT_SIZE);
+ if (!salt)
+ return log_oom();
+
+ r = genuine_random_bytes(salt, FIDO2_SALT_SIZE, RANDOM_BLOCK);
+ if (r < 0)
+ return log_error_errno(r, "Failed to generate salt: %m");
+
+ d = fido_dev_new();
+ if (!d)
+ return log_oom();
+
+ r = fido_dev_open(d, device);
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to open FIDO2 device %s: %s", device, fido_strerr(r));
+
+ if (!fido_dev_is_fido2(d))
+ return log_error_errno(SYNTHETIC_ERRNO(ENODEV),
+ "Specified device %s is not a FIDO2 device.", device);
+
+ di = fido_cbor_info_new();
+ if (!di)
+ return log_oom();
+
+ r = fido_dev_get_cbor_info(d, di);
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to get CBOR device info for %s: %s", device, fido_strerr(r));
+
+ e = fido_cbor_info_extensions_ptr(di);
+ n = fido_cbor_info_extensions_len(di);
+
+ for (size_t i = 0; i < n; i++)
+ if (streq(e[i], "hmac-secret")) {
+ found_extension = true;
+ break;
+ }
+
+ if (!found_extension)
+ return log_error_errno(SYNTHETIC_ERRNO(ENODEV),
+ "Specified device %s is a FIDO2 device, but does not support the required HMAC-SECRET extension.", device);
+
+ c = fido_cred_new();
+ if (!c)
+ return log_oom();
+
+ r = fido_cred_set_extensions(c, FIDO_EXT_HMAC_SECRET);
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to enable HMAC-SECRET extension on FIDO2 credential: %s", fido_strerr(r));
+
+ r = fido_cred_set_rp(c, "io.systemd.home", "Home Directory");
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to set FIDO2 credential relying party ID/name: %s", fido_strerr(r));
+
+ r = fido_cred_set_type(c, COSE_ES256);
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to set FIDO2 credential type to ES256: %s", fido_strerr(r));
+
+ un = json_variant_by_key(*v, "userName");
+ if (!un)
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+ "userName field of user record is missing");
+ if (!json_variant_is_string(un))
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+ "userName field of user record is not a string");
+
+ realm = json_variant_by_key(*v, "realm");
+ if (realm) {
+ if (!json_variant_is_string(realm))
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+ "realm field of user record is not a string");
+
+ fido_un = strjoina(json_variant_string(un), json_variant_string(realm));
+ } else
+ fido_un = json_variant_string(un);
+
+ rn = json_variant_by_key(*v, "realName");
+ if (rn && !json_variant_is_string(rn))
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+ "realName field of user record is not a string");
+
+ r = fido_cred_set_user(c,
+ (const unsigned char*) fido_un, strlen(fido_un), /* We pass the user ID and name as the same */
+ fido_un,
+ rn ? json_variant_string(rn) : NULL,
+ NULL /* icon URL */);
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to set FIDO2 credential user data: %s", fido_strerr(r));
+
+ r = fido_cred_set_clientdata_hash(c, (const unsigned char[32]) {}, 32);
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to set FIDO2 client data hash: %s", fido_strerr(r));
+
+ r = fido_cred_set_rk(c, FIDO_OPT_FALSE);
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to turn off FIDO2 resident key option of credential: %s", fido_strerr(r));
+
+ r = fido_cred_set_uv(c, FIDO_OPT_FALSE);
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to turn off FIDO2 user verification option of credential: %s", fido_strerr(r));
+
+ log_info("Initializing FIDO2 credential on security token.");
+
+ log_notice("%s%s(Hint: This might require verification of user presence on security token.)",
+ emoji_enabled() ? special_glyph(SPECIAL_GLYPH_TOUCH) : "",
+ emoji_enabled() ? " " : "");
+
+ r = fido_dev_make_cred(d, c, NULL);
+ if (r == FIDO_ERR_PIN_REQUIRED) {
+ _cleanup_free_ char *text = NULL;
+
+ if (asprintf(&text, "Please enter security token PIN:") < 0)
+ return log_oom();
+
+ for (;;) {
+ _cleanup_(strv_free_erasep) char **pin = NULL;
+ char **i;
+
+ r = ask_password_auto(text, "user-home", NULL, "fido2-pin", USEC_INFINITY, 0, &pin);
+ if (r < 0)
+ return log_error_errno(r, "Failed to acquire user PIN: %m");
+
+ r = FIDO_ERR_PIN_INVALID;
+ STRV_FOREACH(i, pin) {
+ if (isempty(*i)) {
+ log_info("PIN may not be empty.");
+ continue;
+ }
+
+ r = fido_dev_make_cred(d, c, *i);
+ if (r == FIDO_OK) {
+ used_pin = strdup(*i);
+ if (!used_pin)
+ return log_oom();
+ break;
+ }
+ if (r != FIDO_ERR_PIN_INVALID)
+ break;
+ }
+
+ if (r != FIDO_ERR_PIN_INVALID)
+ break;
+
+ log_notice("PIN incorrect, please try again.");
+ }
+ }
+ if (r == FIDO_ERR_PIN_AUTH_BLOCKED)
+ return log_notice_errno(SYNTHETIC_ERRNO(EPERM),
+ "Token PIN is currently blocked, please remove and reinsert token.");
+ if (r == FIDO_ERR_ACTION_TIMEOUT)
+ return log_error_errno(SYNTHETIC_ERRNO(ENOSTR),
+ "Token action timeout. (User didn't interact with token quickly enough.)");
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to generate FIDO2 credential: %s", fido_strerr(r));
+
+ cid = fido_cred_id_ptr(c);
+ if (!cid)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to get FIDO2 credential ID.");
+
+ cid_size = fido_cred_id_len(c);
+
+ a = fido_assert_new();
+ if (!a)
+ return log_oom();
+
+ r = fido_assert_set_extensions(a, FIDO_EXT_HMAC_SECRET);
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to enable HMAC-SECRET extension on FIDO2 assertion: %s", fido_strerr(r));
+
+ r = fido_assert_set_hmac_salt(a, salt, FIDO2_SALT_SIZE);
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to set salt on FIDO2 assertion: %s", fido_strerr(r));
+
+ r = fido_assert_set_rp(a, "io.systemd.home");
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to set FIDO2 assertion ID: %s", fido_strerr(r));
+
+ r = fido_assert_set_clientdata_hash(a, (const unsigned char[32]) {}, 32);
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to set FIDO2 assertion client data hash: %s", fido_strerr(r));
+
+ r = fido_assert_allow_cred(a, cid, cid_size);
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to add FIDO2 assertion credential ID: %s", fido_strerr(r));
+
+ r = fido_assert_set_up(a, FIDO_OPT_FALSE);
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to turn off FIDO2 assertion user presence: %s", fido_strerr(r));
+
+ log_info("Generating secret key on FIDO2 security token.");
+
+ r = fido_dev_get_assert(d, a, used_pin);
+ if (r == FIDO_ERR_UP_REQUIRED) {
+ r = fido_assert_set_up(a, FIDO_OPT_TRUE);
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to turn on FIDO2 assertion user presence: %s", fido_strerr(r));
+
+ log_notice("%s%sIn order to allow secret key generation, please verify presence on security token.",
+ emoji_enabled() ? special_glyph(SPECIAL_GLYPH_TOUCH) : "",
+ emoji_enabled() ? " " : "");
+
+ r = fido_dev_get_assert(d, a, used_pin);
+ }
+ if (r == FIDO_ERR_ACTION_TIMEOUT)
+ return log_error_errno(SYNTHETIC_ERRNO(ENOSTR),
+ "Token action timeout. (User didn't interact with token quickly enough.)");
+ if (r != FIDO_OK)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to ask token for assertion: %s", fido_strerr(r));
+
+ secret = fido_assert_hmac_secret_ptr(a, 0);
+ if (!secret)
+ return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to retrieve HMAC secret.");
+
+ secret_size = fido_assert_hmac_secret_len(a, 0);
+
+ r = add_fido2_credential_id(v, cid, cid_size);
+ if (r < 0)
+ return r;
+
+ r = add_fido2_salt(v,
+ cid,
+ cid_size,
+ salt,
+ FIDO2_SALT_SIZE,
+ secret,
+ secret_size);
+ if (r < 0)
+ return r;
+
+ /* If we acquired the PIN also include it in the secret section of the record, so that systemd-homed
+ * can use it if it needs to, given that it likely needs to decrypt the key again to pass to LUKS or
+ * fscrypt. */
+ r = identity_add_token_pin(v, used_pin);
+ if (r < 0)
+ return r;
+
+ return 0;
+#else
+ return log_error_errno(EOPNOTSUPP, "FIDO2 tokens not supported on this build.");
+#endif
+}
+
+int list_fido2_devices(void) {
+#if HAVE_LIBFIDO2
+ _cleanup_(table_unrefp) Table *t = NULL;
+ size_t allocated = 64, found = 0;
+ fido_dev_info_t *di = NULL;
+ int r;
+
+ di = fido_dev_info_new(allocated);
+ if (!di)
+ return log_oom();
+
+ r = fido_dev_info_manifest(di, allocated, &found);
+ if (r == FIDO_ERR_INTERNAL || (r == FIDO_OK && found == 0)) {
+ /* The library returns FIDO_ERR_INTERNAL when no devices are found. I wish it wouldn't. */
+ log_info("No FIDO2 devices found.");
+ r = 0;
+ goto finish;
+ }
+ if (r != FIDO_OK) {
+ r = log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to enumerate FIDO2 devices: %s", fido_strerr(r));
+ goto finish;
+ }
+
+ t = table_new("path", "manufacturer", "product");
+ if (!t) {
+ r = log_oom();
+ goto finish;
+ }
+
+ for (size_t i = 0; i < found; i++) {
+ const fido_dev_info_t *entry;
+
+ entry = fido_dev_info_ptr(di, i);
+ if (!entry) {
+ r = log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to get device information for FIDO device %zu.", i);
+ goto finish;
+ }
+
+ r = table_add_many(
+ t,
+ TABLE_PATH, fido_dev_info_path(entry),
+ TABLE_STRING, fido_dev_info_manufacturer_string(entry),
+ TABLE_STRING, fido_dev_info_product_string(entry));
+ if (r < 0) {
+ table_log_add_error(r);
+ goto finish;
+ }
+ }
+
+ r = table_print(t, stdout);
+ if (r < 0) {
+ log_error_errno(r, "Failed to show device table: %m");
+ goto finish;
+ }
+
+ r = 0;
+
+finish:
+ fido_dev_info_free(&di, allocated);
+ return r;
+#else
+ return log_error_errno(EOPNOTSUPP, "FIDO2 tokens not supported on this build.");
+#endif
+}
+
+int find_fido2_auto(char **ret) {
+#if HAVE_LIBFIDO2
+ _cleanup_free_ char *copy = NULL;
+ size_t di_size = 64, found = 0;
+ const fido_dev_info_t *entry;
+ fido_dev_info_t *di = NULL;
+ const char *path;
+ int r;
+
+ di = fido_dev_info_new(di_size);
+ if (!di)
+ return log_oom();
+
+ r = fido_dev_info_manifest(di, di_size, &found);
+ if (r == FIDO_ERR_INTERNAL || (r == FIDO_OK && found == 0)) {
+ /* The library returns FIDO_ERR_INTERNAL when no devices are found. I wish it wouldn't. */
+ r = log_error_errno(SYNTHETIC_ERRNO(ENODEV), "No FIDO2 devices found.");
+ goto finish;
+ }
+ if (r != FIDO_OK) {
+ r = log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to enumerate FIDO2 devices: %s", fido_strerr(r));
+ goto finish;
+ }
+ if (found > 1) {
+ r = log_error_errno(SYNTHETIC_ERRNO(ENOTUNIQ), "More than one FIDO2 device found.");
+ goto finish;
+ }
+
+ entry = fido_dev_info_ptr(di, 0);
+ if (!entry) {
+ r = log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to get device information for FIDO device 0.");
+ goto finish;
+ }
+
+ path = fido_dev_info_path(entry);
+ if (!path) {
+ r = log_error_errno(SYNTHETIC_ERRNO(EIO),
+ "Failed to query FIDO device path.");
+ goto finish;
+ }
+
+ copy = strdup(path);
+ if (!copy) {
+ r = log_oom();
+ goto finish;
+ }
+
+ *ret = TAKE_PTR(copy);
+ r = 0;
+
+finish:
+ fido_dev_info_free(&di, di_size);
+ return r;
+#else
+ return log_error_errno(EOPNOTSUPP, "FIDO2 tokens not supported on this build.");
+#endif
+}
projects / thirdparty / systemd.git / blobdiff