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