diff options
Diffstat (limited to 'src/home/homectl-fido2.c')
| -rw-r--r-- | src/home/homectl-fido2.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/src/home/homectl-fido2.c b/src/home/homectl-fido2.c new file mode 100644 index 0000000..61f0d08 --- /dev/null +++ b/src/home/homectl-fido2.c @@ -0,0 +1,209 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#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 "libfido2-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, + Fido2EnrollFlags lock_with) { + + _cleanup_(json_variant_unrefp) JsonVariant *l = NULL, *w = NULL, *e = NULL; + _cleanup_(erase_and_freep) char *base64_encoded = NULL, *hashed = NULL; + int r; + + /* 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"); + + 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("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(hashed)), + JSON_BUILD_PAIR("up", JSON_BUILD_BOOLEAN(FLAGS_SET(lock_with, FIDO2ENROLL_UP))), + JSON_BUILD_PAIR("uv", JSON_BUILD_BOOLEAN(FLAGS_SET(lock_with, FIDO2ENROLL_UV))), + JSON_BUILD_PAIR("clientPin", JSON_BUILD_BOOLEAN(FLAGS_SET(lock_with, FIDO2ENROLL_PIN))))); + + 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 + +int identity_add_fido2_parameters( + JsonVariant **v, + const char *device, + Fido2EnrollFlags lock_with, + int cred_alg) { + +#if HAVE_LIBFIDO2 + JsonVariant *un, *realm, *rn; + _cleanup_(erase_and_freep) void *secret = NULL, *salt = NULL; + _cleanup_(erase_and_freep) char *used_pin = NULL; + size_t cid_size, salt_size, secret_size; + _cleanup_free_ void *cid = NULL; + const char *fido_un; + int r; + + assert(v); + assert(device); + + 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 = fido2_generate_hmac_hash( + device, + /* rp_id= */ "io.systemd.home", + /* rp_name= */ "Home Directory", + /* user_id= */ fido_un, strlen(fido_un), /* We pass the user ID and name as the same */ + /* user_name= */ fido_un, + /* user_display_name= */ rn ? json_variant_string(rn) : NULL, + /* user_icon_name= */ NULL, + /* askpw_icon_name= */ "user-home", + lock_with, + cred_alg, + &cid, &cid_size, + &salt, &salt_size, + &secret, &secret_size, + &used_pin, + &lock_with); + if (r < 0) + return r; + + r = add_fido2_credential_id( + v, + cid, + cid_size); + if (r < 0) + return r; + + r = add_fido2_salt( + v, + cid, + cid_size, + salt, + salt_size, + secret, + secret_size, + lock_with); + 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(SYNTHETIC_ERRNO(EOPNOTSUPP), + "FIDO2 tokens not supported on this build."); +#endif +} |