-struct pkcs11_callback_data {
- char *pin_used;
- X509 *cert;
-};
-
-static void pkcs11_callback_data_release(struct pkcs11_callback_data *data) {
- erase_and_free(data->pin_used);
- X509_free(data->cert);
-}
-
-#if HAVE_P11KIT
-static int pkcs11_callback(
- CK_FUNCTION_LIST *m,
- CK_SESSION_HANDLE session,
- CK_SLOT_ID slot_id,
- const CK_SLOT_INFO *slot_info,
- const CK_TOKEN_INFO *token_info,
- P11KitUri *uri,
- void *userdata) {
-
- _cleanup_(erase_and_freep) char *pin_used = NULL;
- struct pkcs11_callback_data *data = userdata;
- CK_OBJECT_HANDLE object;
- int r;
-
- assert(m);
- assert(slot_info);
- assert(token_info);
- assert(uri);
- assert(data);
-
- /* Called for every token matching our URI */
-
- r = pkcs11_token_login(m, session, slot_id, token_info, "home directory operation", "user-home", "pkcs11-pin", UINT64_MAX, &pin_used);
- if (r < 0)
- return r;
-
- r = pkcs11_token_find_x509_certificate(m, session, uri, &object);
- if (r < 0)
- return r;
-
- r = pkcs11_token_read_x509_certificate(m, session, object, &data->cert);
- if (r < 0)
- return r;
-
- /* Let's read some random data off the token and write it to the kernel pool before we generate our
- * random key from it. This way we can claim the quality of the RNG is at least as good as the
- * kernel's and the token's pool */
- (void) pkcs11_token_acquire_rng(m, session);
-
- data->pin_used = TAKE_PTR(pin_used);
- return 1;
-}
-#endif
-
-static int acquire_pkcs11_certificate(
- const char *uri,
- X509 **ret_cert,
- char **ret_pin_used) {
-
-#if HAVE_P11KIT
- _cleanup_(pkcs11_callback_data_release) struct pkcs11_callback_data data = {};
- int r;
-
- r = pkcs11_find_token(uri, pkcs11_callback, &data);
- if (r == -EAGAIN) /* pkcs11_find_token() doesn't log about this error, but all others */
- return log_error_errno(ENXIO, "Specified PKCS#11 token with URI '%s' not found.", uri);
- if (r < 0)
- return r;
-
- *ret_cert = TAKE_PTR(data.cert);
- *ret_pin_used = TAKE_PTR(data.pin_used);
-
- return 0;
-#else
- return log_error_errno(EOPNOTSUPP, "PKCS#11 tokens not supported on this build.");
-#endif
-}
-
-static int encrypt_bytes(
- EVP_PKEY *pkey,
- const void *decrypted_key,
- size_t decrypted_key_size,
- void **ret_encrypt_key,
- size_t *ret_encrypt_key_size) {
-
- _cleanup_(EVP_PKEY_CTX_freep) EVP_PKEY_CTX *ctx = NULL;
- _cleanup_free_ void *b = NULL;
- size_t l;
-
- ctx = EVP_PKEY_CTX_new(pkey, NULL);
- if (!ctx)
- return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to allocate public key context");
-
- if (EVP_PKEY_encrypt_init(ctx) <= 0)
- return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to initialize public key context");
-
- if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_PADDING) <= 0)
- return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to configure PKCS#1 padding");
-
- if (EVP_PKEY_encrypt(ctx, NULL, &l, decrypted_key, decrypted_key_size) <= 0)
- return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to determine encrypted key size");
-
- b = malloc(l);
- if (!b)
- return log_oom();
-
- if (EVP_PKEY_encrypt(ctx, b, &l, decrypted_key, decrypted_key_size) <= 0)
- return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to determine encrypted key size");
-
- *ret_encrypt_key = TAKE_PTR(b);
- *ret_encrypt_key_size = l;
-
- return 0;
-}
-
-static int add_pkcs11_pin(JsonVariant **v, const char *pin) {
- _cleanup_(json_variant_unrefp) JsonVariant *w = NULL, *l = NULL;
- _cleanup_(strv_free_erasep) char **pins = NULL;
- int r;
-
- assert(v);
-
- if (isempty(pin))
- return 0;
-
- w = json_variant_ref(json_variant_by_key(*v, "secret"));
- l = json_variant_ref(json_variant_by_key(w, "pkcs11Pin"));
-
- r = json_variant_strv(l, &pins);
- if (r < 0)
- return log_error_errno(r, "Failed to convert PIN array: %m");
-
- if (strv_find(pins, pin))
- return 0;
-
- r = strv_extend(&pins, pin);
- if (r < 0)
- return log_oom();
-
- strv_uniq(pins);
-
- l = json_variant_unref(l);
-
- r = json_variant_new_array_strv(&l, pins);
- if (r < 0)
- return log_error_errno(r, "Failed to allocate new PIN array JSON: %m");
-
- json_variant_sensitive(l);
-
- r = json_variant_set_field(&w, "pkcs11Pin", l);
- if (r < 0)
- return log_error_errno(r, "Failed to update PIN field: %m");
-
- r = json_variant_set_field(v, "secret", w);
- if (r < 0)
- return log_error_errno(r, "Failed to update secret object: %m");
-
- return 1;
-}
-
-static int add_pkcs11_encrypted_key(
- JsonVariant **v,
- const char *uri,
- const void *encrypted_key, size_t encrypted_key_size,
- const void *decrypted_key, size_t decrypted_key_size) {
-
- _cleanup_(json_variant_unrefp) JsonVariant *l = NULL, *w = NULL, *e = NULL;
- _cleanup_(erase_and_freep) char *base64_encoded = NULL;
- _cleanup_free_ char *salt = NULL;
- struct crypt_data cd = {};
- char *k;
- int r;
-
- assert(v);
- assert(uri);
- assert(encrypted_key);
- assert(encrypted_key_size > 0);
- assert(decrypted_key);
- assert(decrypted_key_size > 0);
-
- r = make_salt(&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(decrypted_key, decrypted_key_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, 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("uri", JSON_BUILD_STRING(uri)),
- JSON_BUILD_PAIR("data", JSON_BUILD_BASE64(encrypted_key, encrypted_key_size)),
- JSON_BUILD_PAIR("hashedPassword", JSON_BUILD_STRING(k))));
- if (r < 0)
- return log_error_errno(r, "Failed to build encrypted JSON key object: %m");
-
- w = json_variant_ref(json_variant_by_key(*v, "privileged"));
- l = json_variant_ref(json_variant_by_key(w, "pkcs11EncryptedKey"));
-
- r = json_variant_append_array(&l, e);
- if (r < 0)
- return log_error_errno(r, "Failed append PKCS#11 encrypted key: %m");
-
- r = json_variant_set_field(&w, "pkcs11EncryptedKey", l);
- if (r < 0)
- return log_error_errno(r, "Failed to set PKCS#11 encrypted key: %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;
-}
-
-static int add_pkcs11_token_uri(JsonVariant **v, const char *uri) {
- _cleanup_(json_variant_unrefp) JsonVariant *w = NULL;
- _cleanup_strv_free_ char **l = NULL;
- int r;
-
- assert(v);
- assert(uri);
-
- w = json_variant_ref(json_variant_by_key(*v, "pkcs11TokenUri"));
- if (w) {
- r = json_variant_strv(w, &l);
- if (r < 0)
- return log_error_errno(r, "Failed to parse PKCS#11 token list: %m");
-
- if (strv_contains(l, uri))
- return 0;
- }
-
- r = strv_extend(&l, uri);
- 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 PKCS#11 token URI JSON: %m");
-
- r = json_variant_set_field(v, "pkcs11TokenUri", w);
- if (r < 0)
- return log_error_errno(r, "Failed to update PKCS#11 token URI list: %m");
-
- return 0;
-}
-
-static int add_pkcs11_key_data(JsonVariant **v, const char *uri) {
- _cleanup_(erase_and_freep) void *decrypted_key = NULL, *encrypted_key = NULL;
- _cleanup_(erase_and_freep) char *pin = NULL;
- size_t decrypted_key_size, encrypted_key_size;
- _cleanup_(X509_freep) X509 *cert = NULL;
- EVP_PKEY *pkey;
- RSA *rsa;
- int bits;
- int r;
-
- assert(v);
-
- r = acquire_pkcs11_certificate(uri, &cert, &pin);
- if (r < 0)
- return r;
-
- pkey = X509_get0_pubkey(cert);
- if (!pkey)
- return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to extract public key from X.509 certificate.");
-
- if (EVP_PKEY_base_id(pkey) != EVP_PKEY_RSA)
- return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "X.509 certificate does not refer to RSA key.");
-
- rsa = EVP_PKEY_get0_RSA(pkey);
- if (!rsa)
- return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to acquire RSA public key from X.509 certificate.");
-
- bits = RSA_bits(rsa);
- log_debug("Bits in RSA key: %i", bits);
-
- /* We use PKCS#1 padding for the RSA cleartext, hence let's leave some extra space for it, hence only
- * generate a random key half the size of the RSA length */
- decrypted_key_size = bits / 8 / 2;
-
- if (decrypted_key_size < 1)
- return log_error_errno(SYNTHETIC_ERRNO(EIO), "Uh, RSA key size too short?");
-
- log_debug("Generating %zu bytes random key.", decrypted_key_size);
-
- decrypted_key = malloc(decrypted_key_size);
- if (!decrypted_key)
- return log_oom();
-
- r = genuine_random_bytes(decrypted_key, decrypted_key_size, RANDOM_BLOCK);
- if (r < 0)
- return log_error_errno(r, "Failed to generate random key: %m");
-
- r = encrypt_bytes(pkey, decrypted_key, decrypted_key_size, &encrypted_key, &encrypted_key_size);
- if (r < 0)
- return log_error_errno(r, "Failed to encrypt key: %m");
-
- /* Add the token URI to the public part of the record. */
- r = add_pkcs11_token_uri(v, uri);
- if (r < 0)
- return r;
-
- /* Include the encrypted version of the random key we just generated in the privileged part of the record */
- r = add_pkcs11_encrypted_key(
- v,
- uri,
- encrypted_key, encrypted_key_size,
- decrypted_key, decrypted_key_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 = add_pkcs11_pin(v, pin);
- if (r < 0)
- return r;
-
- return 0;
-}
-