| /* 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 |
| } |