diff options
Diffstat (limited to 'src/home/homectl-pkcs11.c')
| -rw-r--r-- | src/home/homectl-pkcs11.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/src/home/homectl-pkcs11.c b/src/home/homectl-pkcs11.c new file mode 100644 index 0000000..2539af0 --- /dev/null +++ b/src/home/homectl-pkcs11.c @@ -0,0 +1,218 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include "errno-util.h" +#include "format-table.h" +#include "hexdecoct.h" +#include "homectl-pkcs11.h" +#include "libcrypt-util.h" +#include "memory-util.h" +#include "openssl-util.h" +#include "pkcs11-util.h" +#include "random-util.h" +#include "strv.h" + +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, *hashed = NULL; + ssize_t base64_encoded_size; + int r; + + assert(v); + assert(uri); + assert(encrypted_key); + assert(encrypted_key_size > 0); + assert(decrypted_key); + assert(decrypted_key_size > 0); + + /* 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 */ + base64_encoded_size = base64mem(decrypted_key, decrypted_key_size, &base64_encoded); + if (base64_encoded_size < 0) + return log_error_errno(base64_encoded_size, "Failed to base64 encode secret key: %m"); + + r = hash_password(base64_encoded, &hashed); + if (r < 0) + 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(hashed)))); + 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; +} + +int identity_add_token_pin(JsonVariant **v, const char *pin) { + _cleanup_(json_variant_unrefp) JsonVariant *w = NULL, *l = NULL; + _cleanup_strv_free_erase_ 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, "tokenPin")); + + r = json_variant_strv(l, &pins); + if (r < 0) + return log_error_errno(r, "Failed to convert PIN array: %m"); + + if (strv_contains(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, "tokenPin", 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 acquire_pkcs11_certificate( + const char *uri, + const char *askpw_friendly_name, + const char *askpw_icon_name, + X509 **ret_cert, + char **ret_pin_used) { +#if HAVE_P11KIT + return pkcs11_acquire_certificate(uri, askpw_friendly_name, askpw_icon_name, ret_cert, ret_pin_used); +#else + return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), + "PKCS#11 tokens not supported on this build."); +#endif +} + +int identity_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; + int r; + + assert(v); + + r = acquire_pkcs11_certificate(uri, "home directory operation", "user-home", &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."); + + r = rsa_pkey_to_suitable_key_size(pkey, &decrypted_key_size); + if (r < 0) + return log_error_errno(r, "Failed to extract RSA key size from X509 certificate."); + + log_debug("Generating %zu bytes random key.", decrypted_key_size); + + decrypted_key = malloc(decrypted_key_size); + if (!decrypted_key) + return log_oom(); + + r = crypto_random_bytes(decrypted_key, decrypted_key_size); + if (r < 0) + return log_error_errno(r, "Failed to generate random key: %m"); + + r = rsa_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 = identity_add_token_pin(v, pin); + if (r < 0) + return r; + + return 0; +} |