homed: add support for authenticating with fido2 hmac-secret tokens

meson.build

@@ -2157,7 +2157,8 @@ if conf.get('ENABLE_HOMED') == 1
                                 libcrypt,
                                 libopenssl,
                                 libfdisk,
-                                libp11kit],
+                                libp11kit,
+                                libfido2],
                 install_rpath : rootlibexecdir,
                 install : true,
                 install_dir : rootlibexecdir)

src/home/homectl.c

@@ -331,8 +331,18 @@ static int handle_generic_user_record_error(
                 if (r < 0)
                         return log_error_errno(r, "Failed to set PKCS#11 protected authentication path permitted flag: %m");
 
+        } else if (sd_bus_error_has_name(error, BUS_ERROR_TOKEN_USER_PRESENCE_NEEDED)) {
+
+                log_notice("%s%sAuthentication requires presence verification on security token.",
+                           emoji_enabled() ? special_glyph(SPECIAL_GLYPH_TOUCH) : "",
+                           emoji_enabled() ? " " : "");
+
+                r = user_record_set_fido2_user_presence_permitted(hr, true);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to set FIDO2 user presence permitted flag: %m");
+
         } else if (sd_bus_error_has_name(error, BUS_ERROR_TOKEN_PIN_LOCKED))
-                return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Security token PIN is locked, please unlock security token PIN first.");
+                return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Security token PIN is locked, please unlock it first. (Hint: Removal and re-insertion might suffice.)");
 
         else if (sd_bus_error_has_name(error, BUS_ERROR_TOKEN_BAD_PIN)) {
 

src/home/homed-home.c

@@ -457,6 +457,10 @@ static int convert_worker_errno(Home *h, int e, sd_bus_error *error) {
                 return sd_bus_error_setf(error, BUS_ERROR_TOKEN_PIN_NEEDED, "PIN for security token required.");
         case -ERFKILL:
                 return sd_bus_error_setf(error, BUS_ERROR_TOKEN_PROTECTED_AUTHENTICATION_PATH_NEEDED, "Security token requires protected authentication path.");
+        case -EMEDIUMTYPE:
+                return sd_bus_error_setf(error, BUS_ERROR_TOKEN_USER_PRESENCE_NEEDED, "Security token requires user presence.");
+        case -ENOSTR:
+                return sd_bus_error_setf(error, BUS_ERROR_TOKEN_ACTION_TIMEOUT, "Token action timeout. (User was supposed to verify presence or similar, by interacting with the token, and didn't do that in time.)");
         case -EOWNERDEAD:
                 return sd_bus_error_setf(error, BUS_ERROR_TOKEN_PIN_LOCKED, "PIN of security token locked.");
         case -ENOLCK:
@@ -1357,7 +1361,13 @@ static int user_record_extend_with_binding(UserRecord *hr, UserRecord *with_bind
         return 0;
 }
 
-static int home_update_internal(Home *h, const char *verb, UserRecord *hr, UserRecord *secret, sd_bus_error *error) {
+static int home_update_internal(
+                Home *h,
+                const char *verb,
+                UserRecord *hr,
+                UserRecord *secret,
+                sd_bus_error *error) {
+
         _cleanup_(user_record_unrefp) UserRecord *new_hr = NULL, *saved_secret = NULL, *signed_hr = NULL;
         int r, c;
 

src/home/homework-cifs.c

@@ -98,7 +98,7 @@ int home_prepare_cifs(
 
 int home_activate_cifs(
                 UserRecord *h,
-                char ***pkcs11_decrypted_passwords,
+                PasswordCache *cache,
                 UserRecord **ret_home) {
 
         _cleanup_(home_setup_undo) HomeSetup setup = HOME_SETUP_INIT;
@@ -120,7 +120,7 @@ int home_activate_cifs(
         if (r < 0)
                 return r;
 
-        r = home_refresh(h, &setup, NULL, pkcs11_decrypted_passwords, NULL, &new_home);
+        r = home_refresh(h, &setup, NULL, cache, NULL, &new_home);
         if (r < 0)
                 return r;
 

src/home/homework-cifs.h

@@ -6,6 +6,6 @@
 
 int home_prepare_cifs(UserRecord *h, bool already_activated, HomeSetup *setup);
 
-int home_activate_cifs(UserRecord *h, char ***pkcs11_decrypted_passwords, UserRecord **ret_home);
+int home_activate_cifs(UserRecord *h, PasswordCache *cache, UserRecord **ret_home);
 
 int home_create_cifs(UserRecord *h, UserRecord **ret_home);

src/home/homework-directory.c

@@ -26,7 +26,7 @@ int home_prepare_directory(UserRecord *h, bool already_activated, HomeSetup *set
 
 int home_activate_directory(
                 UserRecord *h,
-                char ***pkcs11_decrypted_passwords,
+                PasswordCache *cache,
                 UserRecord **ret_home) {
 
         _cleanup_(user_record_unrefp) UserRecord *new_home = NULL, *header_home = NULL;
@@ -44,11 +44,11 @@ int home_activate_directory(
         assert_se(hdo = user_record_home_directory(h));
         hd = strdupa(hdo);
 
-        r = home_prepare(h, false, pkcs11_decrypted_passwords, &setup, &header_home);
+        r = home_prepare(h, false, cache, &setup, &header_home);
         if (r < 0)
                 return r;
 
-        r = home_refresh(h, &setup, header_home, pkcs11_decrypted_passwords, NULL, &new_home);
+        r = home_refresh(h, &setup, header_home, cache, NULL, &new_home);
         if (r < 0)
                 return r;
 
@@ -193,7 +193,7 @@ int home_create_directory_or_subvolume(UserRecord *h, UserRecord **ret_home) {
 int home_resize_directory(
                 UserRecord *h,
                 bool already_activated,
-                char ***pkcs11_decrypted_passwords,
+                PasswordCache *cache,
                 HomeSetup *setup,
                 UserRecord **ret_home) {
 
@@ -205,11 +205,11 @@ int home_resize_directory(
         assert(ret_home);
         assert(IN_SET(user_record_storage(h), USER_DIRECTORY, USER_SUBVOLUME, USER_FSCRYPT));
 
-        r = home_prepare(h, already_activated, pkcs11_decrypted_passwords, setup, NULL);
+        r = home_prepare(h, already_activated, cache, setup, NULL);
         if (r < 0)
                 return r;
 
-        r = home_load_embedded_identity(h, setup->root_fd, NULL, USER_RECONCILE_REQUIRE_NEWER_OR_EQUAL, pkcs11_decrypted_passwords, &embedded_home, &new_home);
+        r = home_load_embedded_identity(h, setup->root_fd, NULL, USER_RECONCILE_REQUIRE_NEWER_OR_EQUAL, cache, &embedded_home, &new_home);
         if (r < 0)
                 return r;
 

src/home/homework-directory.h

@@ -5,6 +5,6 @@
 #include "user-record.h"
 
 int home_prepare_directory(UserRecord *h, bool already_activated, HomeSetup *setup);
-int home_activate_directory(UserRecord *h, char ***pkcs11_decrypted_passwords, UserRecord **ret_home);
+int home_activate_directory(UserRecord *h, PasswordCache *cache, UserRecord **ret_home);
 int home_create_directory_or_subvolume(UserRecord *h, UserRecord **ret_home);
-int home_resize_directory(UserRecord *h, bool already_activated, char ***pkcs11_decrypted_passwords, HomeSetup *setup, UserRecord **ret_home);
+int home_resize_directory(UserRecord *h, bool already_activated, PasswordCache *cache, HomeSetup *setup, UserRecord **ret_home);

src/home/homework-fido2.c

@@ -0,0 +1,197 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <fido.h>
+
+#include "hexdecoct.h"
+#include "homework-fido2.h"
+#include "strv.h"
+
+static int fido2_use_specific_token(
+                const char *path,
+                UserRecord *h,
+                UserRecord *secret,
+                const Fido2HmacSalt *salt,
+                char **ret) {
+
+        _cleanup_(fido_cbor_info_free) fido_cbor_info_t *di = NULL;
+        _cleanup_(fido_assert_free) fido_assert_t *a = NULL;
+        _cleanup_(fido_dev_free) fido_dev_t *d = NULL;
+        bool found_extension = false;
+        size_t n, hmac_size;
+        const void *hmac;
+        char **e;
+        int r;
+
+        d = fido_dev_new();
+        if (!d)
+                return log_oom();
+
+        r = fido_dev_open(d, path);
+        if (r != FIDO_OK)
+                return log_error_errno(SYNTHETIC_ERRNO(EIO),
+                                       "Failed to open FIDO2 device %s: %s", path, fido_strerr(r));
+
+        if (!fido_dev_is_fido2(d))
+                return log_error_errno(SYNTHETIC_ERRNO(ENODEV),
+                                       "Specified device %s is not a FIDO2 device.", path);
+
+        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", path, 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.", path);
+
+        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->salt, salt->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, salt->credential.id, salt->credential.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, h->fido2_user_presence_permitted <= 0 ? FIDO_OPT_FALSE : FIDO_OPT_TRUE);
+        if (r != FIDO_OK)
+                return log_error_errno(SYNTHETIC_ERRNO(EIO),
+                                       "Failed to set FIDO2 assertion user presence: %s", fido_strerr(r));
+
+        log_info("Asking FIDO2 token for authentication.");
+
+        r = fido_dev_get_assert(d, a, NULL); /* try without pin first */
+        if (r == FIDO_ERR_PIN_REQUIRED) {
+                char **i;
+
+                /* OK, we needed a pin, try with all pins in turn */
+                STRV_FOREACH(i, secret->token_pin) {
+                        r = fido_dev_get_assert(d, a, *i);
+                        if (r != FIDO_ERR_PIN_INVALID)
+                                break;
+                }
+        }
+
+        switch (r) {
+        case FIDO_OK:
+                break;
+        case FIDO_ERR_NO_CREDENTIALS:
+                return log_error_errno(SYNTHETIC_ERRNO(EBADSLT),
+                                       "Wrong security token; needed credentials not present on token.");
+        case FIDO_ERR_PIN_REQUIRED:
+                return log_error_errno(SYNTHETIC_ERRNO(ENOANO),
+                                       "Security token requires PIN.");
+        case FIDO_ERR_PIN_AUTH_BLOCKED:
+                return log_error_errno(SYNTHETIC_ERRNO(EOWNERDEAD),
+                                       "PIN of security token is blocked, please remove/reinsert token.");
+        case FIDO_ERR_PIN_INVALID:
+                return log_error_errno(SYNTHETIC_ERRNO(ENOLCK),
+                                       "PIN of security token incorrect.");
+        case FIDO_ERR_UP_REQUIRED:
+                return log_error_errno(SYNTHETIC_ERRNO(EMEDIUMTYPE),
+                                       "User presence required.");
+        case FIDO_ERR_ACTION_TIMEOUT:
+                return log_error_errno(SYNTHETIC_ERRNO(ENOSTR),
+                                       "Token action timeout. (User didn't interact with token quickly enough.)");
+        default:
+                return log_error_errno(SYNTHETIC_ERRNO(EIO),
+                                       "Failed to ask token for assertion: %s", fido_strerr(r));
+        }
+
+        hmac = fido_assert_hmac_secret_ptr(a, 0);
+        if (!hmac)
+                return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to retrieve HMAC secret.");
+
+        hmac_size = fido_assert_hmac_secret_len(a, 0);
+
+        r = base64mem(hmac, hmac_size, ret);
+        if (r < 0)
+                return log_error_errno(r, "Failed to base64 encode HMAC secret: %m");
+
+        return 0;
+}
+
+int fido2_use_token(UserRecord *h, UserRecord *secret, const Fido2HmacSalt *salt, char **ret) {
+        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) {
+                /* The library returns FIDO_ERR_INTERNAL when no devices are found. I wish it wouldn't. */
+                r = log_debug_errno(SYNTHETIC_ERRNO(EAGAIN), "Got FIDO_ERR_INTERNAL, assuming no devices.");
+                goto finish;
+        }
+        if (r != FIDO_OK) {
+                r = log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to enumerate FIDO2 devices: %s", fido_strerr(r));
+                goto finish;
+        }
+
+        for (size_t i = 0; i < found; i++) {
+                const fido_dev_info_t *entry;
+                const char *path;
+
+                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;
+                }
+
+                path = fido_dev_info_path(entry);
+                if (!path) {
+                        r = log_error_errno(SYNTHETIC_ERRNO(EIO),
+                                            "Failed to query FIDO device path.");
+                        goto finish;
+                }
+
+                r = fido2_use_specific_token(path, h, secret, salt, ret);
+                if (!IN_SET(r,
+                            -EBADSLT, /* device doesn't understand our credential hash */
+                            -ENODEV   /* device is not a FIDO2 device with HMAC-SECRET */))
+                        goto finish;
+        }
+
+        r = -EAGAIN;
+
+finish:
+        fido_dev_info_free(&di, allocated);
+        return r;
+}

src/home/homework-fido2.h

@@ -0,0 +1,6 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+#pragma once
+
+#include "user-record.h"
+
+int fido2_use_token(UserRecord *h, UserRecord *secret, const Fido2HmacSalt *salt, char **ret);

src/home/homework-fscrypt.c

@@ -208,7 +208,7 @@ static int fscrypt_slot_try_many(
 }
 
 static int fscrypt_setup(
-                char **pkcs11_decrypted_passwords,
+                const PasswordCache *cache,
                 char **password,
                 HomeSetup *setup,
                 void **ret_volume_key,
@@ -230,6 +230,7 @@ static int fscrypt_setup(
                 _cleanup_free_ char *value = NULL;
                 size_t salt_size, encrypted_size;
                 const char *nr, *e;
+                char **list;
                 int n;
 
                 /* Check if this xattr has the format 'trusted.fscrypt_slot<nr>' where '<nr>' is a 32bit unsigned integer */
@@ -256,19 +257,17 @@ static int fscrypt_setup(
                 if (r < 0)
                         return log_error_errno(r, "Failed to decode encrypted key of %s: %m", xa);
 
-                r = fscrypt_slot_try_many(
-                                pkcs11_decrypted_passwords,
-                                salt, salt_size,
-                                encrypted, encrypted_size,
-                                setup->fscrypt_key_descriptor,
-                                ret_volume_key, ret_volume_key_size);
-                if (r == -ENOANO)
+                r = -ENOANO;
+                FOREACH_POINTER(list, cache->pkcs11_passwords, cache->fido2_passwords, password) {
                         r = fscrypt_slot_try_many(
-                                        password,
+                                        list,
                                         salt, salt_size,
                                         encrypted, encrypted_size,
                                         setup->fscrypt_key_descriptor,
                                         ret_volume_key, ret_volume_key_size);
+                        if (r != -ENOANO)
+                                break;
+                }
                 if (r < 0) {
                         if (r != -ENOANO)
                                 return r;
@@ -282,7 +281,7 @@ static int fscrypt_setup(
 int home_prepare_fscrypt(
                 UserRecord *h,
                 bool already_activated,
-                char ***pkcs11_decrypted_passwords,
+                PasswordCache *cache,
                 HomeSetup *setup) {
 
         _cleanup_(erase_and_freep) void *volume_key = NULL;
@@ -314,7 +313,7 @@ int home_prepare_fscrypt(
         memcpy(setup->fscrypt_key_descriptor, policy.master_key_descriptor, FS_KEY_DESCRIPTOR_SIZE);
 
         r = fscrypt_setup(
-                        pkcs11_decrypted_passwords ? *pkcs11_decrypted_passwords : NULL,
+                        cache,
                         h->password,
                         setup,
                         &volume_key,
@@ -584,7 +583,7 @@ int home_create_fscrypt(
 int home_passwd_fscrypt(
                 UserRecord *h,
                 HomeSetup *setup,
-                char **pkcs11_decrypted_passwords, /* the passwords acquired via PKCS#11 security tokens */
+                PasswordCache *cache,               /* the passwords acquired via PKCS#11/FIDO2 security tokens */
                 char **effective_passwords          /* new passwords */) {
 
         _cleanup_(erase_and_freep) void *volume_key = NULL;
@@ -600,7 +599,7 @@ int home_passwd_fscrypt(
         assert(setup);
 
         r = fscrypt_setup(
-                        pkcs11_decrypted_passwords,
+                        cache,
                         h->password,
                         setup,
                         &volume_key,

src/home/homework-fscrypt.h

@@ -4,7 +4,7 @@
 #include "homework.h"
 #include "user-record.h"
 
-int home_prepare_fscrypt(UserRecord *h, bool already_activated, char ***pkcs11_decrypted_passwords, HomeSetup *setup);
+int home_prepare_fscrypt(UserRecord *h, bool already_activated, PasswordCache *cache, HomeSetup *setup);
 int home_create_fscrypt(UserRecord *h, char **effective_passwords, UserRecord **ret_home);
 
-int home_passwd_fscrypt(UserRecord *h, HomeSetup *setup, char **pkcs11_decrypted_passwords, char **effective_passwords);
+int home_passwd_fscrypt(UserRecord *h, HomeSetup *setup, PasswordCache *cache, char **effective_passwords);

src/home/homework-luks.c

@@ -216,7 +216,7 @@ static int luks_setup(
                 const char *cipher_mode,
                 uint64_t volume_key_size,
                 char **passwords,
-                char **pkcs11_decrypted_passwords,
+                const PasswordCache *cache,
                 bool discard,
                 struct crypt_device **ret,
                 sd_id128_t *ret_found_uuid,
@@ -227,6 +227,7 @@ static int luks_setup(
         _cleanup_(erase_and_freep) void *vk = NULL;
         sd_id128_t p;
         size_t vks;
+        char **list;
         int r;
 
         assert(node);
@@ -278,12 +279,14 @@ static int luks_setup(
         if (!vk)
                 return log_oom();
 
-        r = luks_try_passwords(cd, pkcs11_decrypted_passwords, vk, &vks);
-        if (r == -ENOKEY) {
-                r = luks_try_passwords(cd, passwords, vk, &vks);
-                if (r == -ENOKEY)
-                        return log_error_errno(r, "No valid password for LUKS superblock.");
+        r = -ENOKEY;
+        FOREACH_POINTER(list, cache->pkcs11_passwords, cache->fido2_passwords, passwords) {
+                r = luks_try_passwords(cd, list, vk, &vks);
+                if (r != -ENOKEY)
+                        break;
         }
+        if (r == -ENOKEY)
+                return log_error_errno(r, "No valid password for LUKS superblock.");
         if (r < 0)
                 return log_error_errno(r, "Failed to unlocks LUKS superblock: %m");
 
@@ -312,7 +315,7 @@ static int luks_setup(
 static int luks_open(
                 const char *dm_name,
                 char **passwords,
-                char **pkcs11_decrypted_passwords,
+                PasswordCache *cache,
                 struct crypt_device **ret,
                 sd_id128_t *ret_found_uuid,
                 void **ret_volume_key,
@@ -321,6 +324,7 @@ static int luks_open(
         _cleanup_(crypt_freep) struct crypt_device *cd = NULL;
         _cleanup_(erase_and_freep) void *vk = NULL;
         sd_id128_t p;
+        char **list;
         size_t vks;
         int r;
 
@@ -361,12 +365,14 @@ static int luks_open(
         if (!vk)
                 return log_oom();
 
-        r = luks_try_passwords(cd, pkcs11_decrypted_passwords, vk, &vks);
-        if (r == -ENOKEY) {
-                r = luks_try_passwords(cd, passwords, vk, &vks);
-                if (r == -ENOKEY)
-                        return log_error_errno(r, "No valid password for LUKS superblock.");
+        r = -ENOKEY;
+        FOREACH_POINTER(list, cache->pkcs11_passwords, cache->fido2_passwords, passwords) {
+                r = luks_try_passwords(cd, list, vk, &vks);
+                if (r != -ENOKEY)
+                        break;
         }
+        if (r == -ENOKEY)
+                return log_error_errno(r, "No valid password for LUKS superblock.");
         if (r < 0)
                 return log_error_errno(r, "Failed to unlocks LUKS superblock: %m");
 
@@ -622,7 +628,7 @@ static int luks_validate_home_record(
                 struct crypt_device *cd,
                 UserRecord *h,
                 const void *volume_key,
-                char ***pkcs11_decrypted_passwords,
+                PasswordCache *cache,
                 UserRecord **ret_luks_home_record) {
 
         int r, token;
@@ -727,7 +733,7 @@ static int luks_validate_home_record(
                 if (!user_record_compatible(h, lhr))
                         return log_error_errno(SYNTHETIC_ERRNO(EREMCHG), "LUKS home record not compatible with host record, refusing.");
 
-                r = user_record_authenticate(lhr, h, pkcs11_decrypted_passwords, /* strict_verify= */ true);
+                r = user_record_authenticate(lhr, h, cache, /* strict_verify= */ true);
                 if (r < 0)
                         return r;
                 assert(r > 0); /* Insist that a password was verified */
@@ -982,7 +988,7 @@ int home_prepare_luks(
                 UserRecord *h,
                 bool already_activated,
                 const char *force_image_path,
-                char ***pkcs11_decrypted_passwords,
+                PasswordCache *cache,
                 HomeSetup *setup,
                 UserRecord **ret_luks_home) {
 
@@ -1010,7 +1016,7 @@ int home_prepare_luks(
 
                 r = luks_open(setup->dm_name,
                               h->password,
-                              pkcs11_decrypted_passwords ? *pkcs11_decrypted_passwords : NULL,
+                              cache,
                               &cd,
                               &found_luks_uuid,
                               &volume_key,
@@ -1018,7 +1024,7 @@ int home_prepare_luks(
                 if (r < 0)
                         return r;
 
-                r = luks_validate_home_record(cd, h, volume_key, pkcs11_decrypted_passwords, &luks_home);
+                r = luks_validate_home_record(cd, h, volume_key, cache, &luks_home);
                 if (r < 0)
                         return r;
 
@@ -1133,7 +1139,7 @@ int home_prepare_luks(
                                h->luks_cipher_mode,
                                h->luks_volume_key_size,
                                h->password,
-                               pkcs11_decrypted_passwords ? *pkcs11_decrypted_passwords : NULL,
+                               cache,
                                user_record_luks_discard(h) || user_record_luks_offline_discard(h),
                                &cd,
                                &found_luks_uuid,
@@ -1144,7 +1150,7 @@ int home_prepare_luks(
 
                 dm_activated = true;
 
-                r = luks_validate_home_record(cd, h, volume_key, pkcs11_decrypted_passwords, &luks_home);
+                r = luks_validate_home_record(cd, h, volume_key, cache, &luks_home);
                 if (r < 0)
                         goto fail;
 
@@ -1218,7 +1224,7 @@ static void print_size_summary(uint64_t host_size, uint64_t encrypted_size, stru
 
 int home_activate_luks(
                 UserRecord *h,
-                char ***pkcs11_decrypted_passwords,
+                PasswordCache *cache,
                 UserRecord **ret_home) {
 
         _cleanup_(user_record_unrefp) UserRecord *new_home = NULL, *luks_home_record = NULL;
@@ -1250,7 +1256,7 @@ int home_activate_luks(
                         h,
                         false,
                         NULL,
-                        pkcs11_decrypted_passwords,
+                        cache,
                         &setup,
                         &luks_home_record);
         if (r < 0)
@@ -1268,7 +1274,7 @@ int home_activate_luks(
                         h,
                         &setup,
                         luks_home_record,
-                        pkcs11_decrypted_passwords,
+                        cache,
                         &sfs,
                         &new_home);
         if (r < 0)
@@ -1464,7 +1470,7 @@ static int luks_format(
                 const char *dm_name,
                 sd_id128_t uuid,
                 const char *label,
-                char **pkcs11_decrypted_passwords,
+                const PasswordCache *cache,
                 char **effective_passwords,
                 bool discard,
                 UserRecord *hr,
@@ -1533,7 +1539,8 @@ static int luks_format(
 
         STRV_FOREACH(pp, effective_passwords) {
 
-                if (strv_contains(pkcs11_decrypted_passwords, *pp)) {
+                if (strv_contains(cache->pkcs11_passwords, *pp) ||
+                    strv_contains(cache->fido2_passwords, *pp)) {
                         log_debug("Using minimal PBKDF for slot %i", slot);
                         r = crypt_set_pbkdf_type(cd, &minimal_pbkdf);
                 } else {
@@ -1858,7 +1865,7 @@ static int home_truncate(
 
 int home_create_luks(
                 UserRecord *h,
-                char **pkcs11_decrypted_passwords,
+                PasswordCache *cache,
                 char **effective_passwords,
                 UserRecord **ret_home) {
 
@@ -2055,7 +2062,7 @@ int home_create_luks(
                         dm_name,
                         luks_uuid,
                         user_record_user_name_and_realm(h),
-                        pkcs11_decrypted_passwords,
+                        cache,
                         effective_passwords,
                         user_record_luks_discard(h) || user_record_luks_offline_discard(h),
                         h,
@@ -2561,7 +2568,7 @@ static int apply_resize_partition(int fd, sd_id128_t disk_uuids, struct fdisk_ta
 int home_resize_luks(
                 UserRecord *h,
                 bool already_activated,
-                char ***pkcs11_decrypted_passwords,
+                PasswordCache *cache,
                 HomeSetup *setup,
                 UserRecord **ret_home) {
 
@@ -2647,11 +2654,11 @@ int home_resize_luks(
                 }
         }
 
-        r = home_prepare_luks(h, already_activated, whole_disk, pkcs11_decrypted_passwords, setup, &header_home);
+        r = home_prepare_luks(h, already_activated, whole_disk, cache, setup, &header_home);
         if (r < 0)
                 return r;
 
-        r = home_load_embedded_identity(h, setup->root_fd, header_home, USER_RECONCILE_REQUIRE_NEWER_OR_EQUAL, pkcs11_decrypted_passwords, &embedded_home, &new_home);
+        r = home_load_embedded_identity(h, setup->root_fd, header_home, USER_RECONCILE_REQUIRE_NEWER_OR_EQUAL, cache, &embedded_home, &new_home);
         if (r < 0)
                 return r;
 
@@ -2855,13 +2862,14 @@ int home_resize_luks(
 int home_passwd_luks(
                 UserRecord *h,
                 HomeSetup *setup,
-                char **pkcs11_decrypted_passwords, /* the passwords acquired via PKCS#11 security tokens */
-                char **effective_passwords         /* new passwords */) {
+                PasswordCache *cache,      /* the passwords acquired via PKCS#11/FIDO2 security tokens */
+                char **effective_passwords /* new passwords */) {
 
         size_t volume_key_size, i, max_key_slots, n_effective;
         _cleanup_(erase_and_freep) void *volume_key = NULL;
         struct crypt_pbkdf_type good_pbkdf, minimal_pbkdf;
         const char *type;
+        char **list;
         int r;
 
         assert(h);
@@ -2886,12 +2894,14 @@ int home_passwd_luks(
         if (!volume_key)
                 return log_oom();
 
-        r = luks_try_passwords(setup->crypt_device, pkcs11_decrypted_passwords, volume_key, &volume_key_size);
-        if (r == -ENOKEY) {
-                r = luks_try_passwords(setup->crypt_device, h->password, volume_key, &volume_key_size);
-                if (r == -ENOKEY)
-                        return log_error_errno(SYNTHETIC_ERRNO(ENOKEY), "Failed to unlock LUKS superblock with supplied passwords.");
+        r = -ENOKEY;
+        FOREACH_POINTER(list, cache->pkcs11_passwords, cache->fido2_passwords, h->password) {
+                r = luks_try_passwords(setup->crypt_device, list, volume_key, &volume_key_size);
+                if (r != -ENOKEY)
+                        break;
         }
+        if (r == -ENOKEY)
+                return log_error_errno(SYNTHETIC_ERRNO(ENOKEY), "Failed to unlock LUKS superblock with supplied passwords.");
         if (r < 0)
                 return log_error_errno(r, "Failed to unlocks LUKS superblock: %m");
 
@@ -2911,7 +2921,8 @@ int home_passwd_luks(
                         continue;
                 }
 
-                if (strv_find(pkcs11_decrypted_passwords, effective_passwords[i])) {
+                if (strv_contains(cache->pkcs11_passwords, effective_passwords[i]) ||
+                    strv_contains(cache->fido2_passwords, effective_passwords[i])) {
                         log_debug("Using minimal PBKDF for slot %zu", i);
                         r = crypt_set_pbkdf_type(setup->crypt_device, &minimal_pbkdf);
                 } else {
@@ -3008,9 +3019,10 @@ static int luks_try_resume(
         return -ENOKEY;
 }
 
-int home_unlock_luks(UserRecord *h, char ***pkcs11_decrypted_passwords) {
+int home_unlock_luks(UserRecord *h, PasswordCache *cache) {
         _cleanup_free_ char *dm_name = NULL, *dm_node = NULL;
         _cleanup_(crypt_freep) struct crypt_device *cd = NULL;
+        char **list;
         int r;
 
         assert(h);
@@ -3026,12 +3038,14 @@ int home_unlock_luks(UserRecord *h, char ***pkcs11_decrypted_passwords) {
         log_info("Discovered used LUKS device %s.", dm_node);
         crypt_set_log_callback(cd, cryptsetup_log_glue, NULL);
 
-        r = luks_try_resume(cd, dm_name, pkcs11_decrypted_passwords ? *pkcs11_decrypted_passwords : NULL);
-        if (r == -ENOKEY) {
-                r = luks_try_resume(cd, dm_name, h->password);
-                if (r == -ENOKEY)
-                        return log_error_errno(r, "No valid password for LUKS superblock.");
+        r = -ENOKEY;
+        FOREACH_POINTER(list, cache->pkcs11_passwords, cache->fido2_passwords, h->password) {
+                r = luks_try_resume(cd, dm_name, list);
+                if (r != -ENOKEY)
+                        break;
         }
+        if (r == -ENOKEY)
+                return log_error_errno(r, "No valid password for LUKS superblock.");
         if (r < 0)
                 return log_error_errno(r, "Failed to resume LUKS superblock: %m");
 

src/home/homework-luks.h

@@ -5,24 +5,24 @@
 #include "homework.h"
 #include "user-record.h"
 
-int home_prepare_luks(UserRecord *h, bool already_activated, const char *force_image_path, char ***pkcs11_decrypted_passwords, HomeSetup *setup, UserRecord **ret_luks_home);
+int home_prepare_luks(UserRecord *h, bool already_activated, const char *force_image_path, PasswordCache *cache, HomeSetup *setup, UserRecord **ret_luks_home);
 
-int home_activate_luks(UserRecord *h, char ***pkcs11_decrypted_passwords, UserRecord **ret_home);
+int home_activate_luks(UserRecord *h, PasswordCache *cache, UserRecord **ret_home);
 int home_deactivate_luks(UserRecord *h);
 int home_trim_luks(UserRecord *h);
 
 int home_store_header_identity_luks(UserRecord *h, HomeSetup *setup, UserRecord *old_home);
 
-int home_create_luks(UserRecord *h, char **pkcs11_decrypted_passwords, char **effective_passwords, UserRecord **ret_home);
+int home_create_luks(UserRecord *h, PasswordCache *cache, char **effective_passwords, UserRecord **ret_home);
 
 int home_validate_update_luks(UserRecord *h, HomeSetup *setup);
 
-int home_resize_luks(UserRecord *h, bool already_activated, char ***pkcs11_decrypted_passwords, HomeSetup *setup, UserRecord **ret_home);
+int home_resize_luks(UserRecord *h, bool already_activated, PasswordCache *cache, HomeSetup *setup, UserRecord **ret_home);
 
-int home_passwd_luks(UserRecord *h, HomeSetup *setup, char **pkcs11_decrypted_passwords, char **effective_passwords);
+int home_passwd_luks(UserRecord *h, HomeSetup *setup, PasswordCache *cache, char **effective_passwords);
 
 int home_lock_luks(UserRecord *h);
-int home_unlock_luks(UserRecord *h, char ***pkcs11_decrypted_passwords);
+int home_unlock_luks(UserRecord *h, PasswordCache *cache);
 
 static inline uint64_t luks_volume_key_size_convert(struct crypt_device *cd) {
         int k;

src/home/homework.c

@@ -11,6 +11,7 @@
 #include "home-util.h"
 #include "homework-cifs.h"
 #include "homework-directory.h"
+#include "homework-fido2.h"
 #include "homework-fscrypt.h"
 #include "homework-luks.h"
 #include "homework-mount.h"
@@ -21,7 +22,6 @@
 #include "missing_magic.h"
 #include "mount-util.h"
 #include "path-util.h"
-#include "pkcs11-util.h"
 #include "rm-rf.h"
 #include "stat-util.h"
 #include "strv.h"
@@ -32,14 +32,22 @@
 /* Make sure a bad password always results in a 3s delay, no matter what */
 #define BAD_PASSWORD_DELAY_USEC (3 * USEC_PER_SEC)
 
+void password_cache_free(PasswordCache *cache) {
+        if (!cache)
+                return;
+
+        cache->pkcs11_passwords = strv_free_erase(cache->pkcs11_passwords);
+        cache->fido2_passwords = strv_free_erase(cache->fido2_passwords);
+}
+
 int user_record_authenticate(
                 UserRecord *h,
                 UserRecord *secret,
-                char ***pkcs11_decrypted_passwords,
+                PasswordCache *cache,
                 bool strict_verify) {
 
-        bool need_password = false, need_token = false, need_pin = false, need_protected_authentication_path_permitted = false,
-                pin_locked = false, pin_incorrect = false, pin_incorrect_few_tries_left = false, pin_incorrect_one_try_left = false;
+        bool need_password = false, need_token = false, need_pin = false, need_protected_authentication_path_permitted = false, need_user_presence_permitted = false,
+                pin_locked = false, pin_incorrect = false, pin_incorrect_few_tries_left = false, pin_incorrect_one_try_left = false, token_action_timeout = false;
         int r;
 
         assert(h);
@@ -47,14 +55,14 @@ int user_record_authenticate(
 
         /* Tries to authenticate a user record with the supplied secrets. i.e. checks whether at least one
          * supplied plaintext passwords matches a hashed password field of the user record. Or if a
-         * configured PKCS#11 token is around and can unlock the record.
+         * configured PKCS#11 or FIDO2 token is around and can unlock the record.
          *
-         * Note that the pkcs11_decrypted_passwords parameter is both an input and and output parameter: it
-         * is a list of configured, decrypted PKCS#11 passwords. We typically have to call this function
-         * multiple times over the course of an operation (think: on login we authenticate the host user
-         * record, the record embedded in the LUKS record and the one embedded in $HOME). Hence we keep a
-         * list of passwords we already decrypted, so that we don't have to do the (slow an potentially
-         * interactive) PKCS#11 dance for the relevant token again and again. */
+         * Note that the 'cache' parameter is both an input and output parameter: it contains lists of
+         * configured, decrypted PKCS#11/FIDO2 passwords. We typically have to call this function multiple
+         * times over the course of an operation (think: on login we authenticate the host user record, the
+         * record embedded in the LUKS record and the one embedded in $HOME). Hence we keep a list of
+         * passwords we already decrypted, so that we don't have to do the (slow and potentially interactive)
+         * PKCS#11/FIDO2 dance for the relevant token again and again. */
 
         /* First, let's see if the supplied plain-text passwords work? */
         r = user_record_test_secret(h, secret);
@@ -70,19 +78,12 @@ int user_record_authenticate(
                 return 1;
         }
 
-        /* Second, let's see if any of the PKCS#11 security tokens are plugged in and help us */
+        /* Second, test cached PKCS#11 passwords */
         for (size_t n = 0; n < h->n_pkcs11_encrypted_key; n++) {
-#if HAVE_P11KIT
-                _cleanup_(pkcs11_callback_data_release) struct pkcs11_callback_data data = {
-                        .user_record = h,
-                        .secret = secret,
-                        .encrypted_key = h->pkcs11_encrypted_key + n,
-                };
                 char **pp;
 
-                /* See if any of the previously calculated passwords work */
-                STRV_FOREACH(pp, *pkcs11_decrypted_passwords) {
-                        r = test_password_one(data.encrypted_key->hashed_password, *pp);
+                STRV_FOREACH(pp, cache->pkcs11_passwords) {
+                        r = test_password_one(h->pkcs11_encrypted_key[n].hashed_password, *pp);
                         if (r < 0)
                                 return log_error_errno(r, "Failed to check supplied PKCS#11 password: %m");
                         if (r > 0) {
@@ -90,6 +91,32 @@ int user_record_authenticate(
                                 return 1;
                         }
                 }
+        }
+
+        /* Third, test cached FIDO2 passwords */
+        for (size_t n = 0; n < h->n_fido2_hmac_salt; n++) {
+                char **pp;
+
+                /* See if any of the previously calculated passwords work */
+                STRV_FOREACH(pp, cache->fido2_passwords) {
+                        r = test_password_one(h->fido2_hmac_salt[n].hashed_password, *pp);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to check supplied FIDO2 password: %m");
+                        if (r > 0) {
+                                log_info("Previously acquired FIDO2 password unlocks user record.");
+                                return 0;
+                        }
+                }
+        }
+
+        /* Fourth, let's see if any of the PKCS#11 security tokens are plugged in and help us */
+        for (size_t n = 0; n < h->n_pkcs11_encrypted_key; n++) {
+#if HAVE_P11KIT
+                _cleanup_(pkcs11_callback_data_release) struct pkcs11_callback_data data = {
+                        .user_record = h,
+                        .secret = secret,
+                        .encrypted_key = h->pkcs11_encrypted_key + n,
+                };
 
                 r = pkcs11_find_token(data.encrypted_key->uri, pkcs11_callback, &data);
                 switch (r) {
@@ -126,7 +153,56 @@ int user_record_authenticate(
 
                         log_info("Decrypted password from PKCS#11 security token %s unlocks user record.", data.encrypted_key->uri);
 
-                        r = strv_extend(pkcs11_decrypted_passwords, data.decrypted_password);
+                        r = strv_extend(&cache->pkcs11_passwords, data.decrypted_password);
+                        if (r < 0)
+                                return log_oom();
+
+                        return 0;
+                }
+#else
+                need_token = true;
+                break;
+#endif
+        }
+
+        /* Fifth, let's see if any of the FIDO2 security tokens are plugged in and help us */
+        for (size_t n = 0; n < h->n_fido2_hmac_salt; n++) {
+#if HAVE_LIBFIDO2
+                _cleanup_(erase_and_freep) char *decrypted_password = NULL;
+
+                r = fido2_use_token(h, secret, h->fido2_hmac_salt + n, &decrypted_password);
+                switch (r) {
+                case -EAGAIN:
+                        need_token = true;
+                        break;
+                case -ENOANO:
+                        need_pin = true;
+                        break;
+                case -EOWNERDEAD:
+                        pin_locked = true;
+                        break;
+                case -ENOLCK:
+                        pin_incorrect = true;
+                        break;
+                case -EMEDIUMTYPE:
+                        need_user_presence_permitted = true;
+                        break;
+                case -ENOSTR:
+                        token_action_timeout = true;
+                        break;
+                default:
+                        if (r < 0)
+                                return r;
+
+                        r = test_password_one(h->fido2_hmac_salt[n].hashed_password, decrypted_password);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to test FIDO2 password: %m");
+                        if (r == 0)
+                                return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Configured FIDO2 security token does not decrypt encrypted key correctly.");
+
+                        log_info("Decrypted password from FIDO2 security token unlocks user record.");
+
+                        r = strv_extend(&cache->fido2_passwords, decrypted_password);
                         if (r < 0)
                                 return log_oom();
 
@@ -147,8 +223,12 @@ int user_record_authenticate(
                 return -ENOLCK;
         if (pin_locked)
                 return -EOWNERDEAD;
+        if (token_action_timeout)
+                return -ENOSTR;
         if (need_protected_authentication_path_permitted)
                 return -ERFKILL;
+        if (need_user_presence_permitted)
+                return -EMEDIUMTYPE;
         if (need_pin)
                 return -ENOANO;
         if (need_token)
@@ -156,10 +236,11 @@ int user_record_authenticate(
         if (need_password)
                 return -ENOKEY;
 
-        /* Hmm, this means neither PCKS#11 nor classic hashed passwords were supplied, we cannot authenticate this reasonably */
+        /* Hmm, this means neither PCKS#11/FIDO2 nor classic hashed passwords were supplied, we cannot
+         * authenticate this reasonably */
         if (strict_verify)
                 return log_debug_errno(SYNTHETIC_ERRNO(EKEYREVOKED),
-                                       "No hashed passwords and no PKCS#11 tokens defined, cannot authenticate user record, refusing.");
+                                       "No hashed passwords and no PKCS#11/FIDO2 tokens defined, cannot authenticate user record, refusing.");
 
         /* If strict verification is off this means we are possibly in the case where we encountered an
          * unfixated record, i.e. a synthetic one that accordingly lacks any authentication data. In this
@@ -230,7 +311,7 @@ int home_setup_undo(HomeSetup *setup) {
 int home_prepare(
                 UserRecord *h,
                 bool already_activated,
-                char ***pkcs11_decrypted_passwords,
+                PasswordCache *cache,
                 HomeSetup *setup,
                 UserRecord **ret_header_home) {
 
@@ -249,7 +330,7 @@ int home_prepare(
         switch (user_record_storage(h)) {
 
         case USER_LUKS:
-                return home_prepare_luks(h, already_activated, NULL, pkcs11_decrypted_passwords, setup, ret_header_home);
+                return home_prepare_luks(h, already_activated, NULL, cache, setup, ret_header_home);
 
         case USER_SUBVOLUME:
         case USER_DIRECTORY:
@@ -257,7 +338,7 @@ int home_prepare(
                 break;
 
         case USER_FSCRYPT:
-                r = home_prepare_fscrypt(h, already_activated, pkcs11_decrypted_passwords, setup);
+                r = home_prepare_fscrypt(h, already_activated, cache, setup);
                 break;
 
         case USER_CIFS:
@@ -387,7 +468,7 @@ int home_load_embedded_identity(
                 int root_fd,
                 UserRecord *header_home,
                 UserReconcileMode mode,
-                char ***pkcs11_decrypted_passwords,
+                PasswordCache *cache,
                 UserRecord **ret_embedded_home,
                 UserRecord **ret_new_home) {
 
@@ -414,7 +495,7 @@ int home_load_embedded_identity(
                 return log_error_errno(SYNTHETIC_ERRNO(EREMCHG), "Embedded home record not compatible with host record, refusing.");
 
         /* Insist that credentials the user supplies also unlocks any embedded records. */
-        r = user_record_authenticate(embedded_home, h, pkcs11_decrypted_passwords, /* strict_verify= */ true);
+        r = user_record_authenticate(embedded_home, h, cache, /* strict_verify= */ true);
         if (r < 0)
                 return r;
         assert(r > 0); /* Insist that a password was verified */
@@ -576,7 +657,7 @@ int home_refresh(
                 UserRecord *h,
                 HomeSetup *setup,
                 UserRecord *header_home,
-                char ***pkcs11_decrypted_passwords,
+                PasswordCache *cache,
                 struct statfs *ret_statfs,
                 UserRecord **ret_new_home) {
 
@@ -590,7 +671,7 @@ int home_refresh(
         /* When activating a home directory, does the identity work: loads the identity from the $HOME
          * directory, reconciles it with our idea, chown()s everything. */
 
-        r = home_load_embedded_identity(h, setup->root_fd, header_home, USER_RECONCILE_ANY, pkcs11_decrypted_passwords, &embedded_home, &new_home);
+        r = home_load_embedded_identity(h, setup->root_fd, header_home, USER_RECONCILE_ANY, cache, &embedded_home, &new_home);
         if (r < 0)
                 return r;
 
@@ -615,7 +696,7 @@ int home_refresh(
 }
 
 static int home_activate(UserRecord *h, UserRecord **ret_home) {
-        _cleanup_(strv_free_erasep) char **pkcs11_decrypted_passwords = NULL;
+        _cleanup_(password_cache_free) PasswordCache cache = {};
         _cleanup_(user_record_unrefp) UserRecord *new_home = NULL;
         int r;
 
@@ -628,7 +709,7 @@ static int home_activate(UserRecord *h, UserRecord **ret_home) {
         if (!IN_SET(user_record_storage(h), USER_LUKS, USER_DIRECTORY, USER_SUBVOLUME, USER_FSCRYPT, USER_CIFS))
                 return log_error_errno(SYNTHETIC_ERRNO(ENOTTY), "Activating home directories of type '%s' currently not supported.", user_storage_to_string(user_record_storage(h)));
 
-        r = user_record_authenticate(h, h, &pkcs11_decrypted_passwords, /* strict_verify= */ false);
+        r = user_record_authenticate(h, h, &cache, /* strict_verify= */ false);
         if (r < 0)
                 return r;
 
@@ -647,7 +728,7 @@ static int home_activate(UserRecord *h, UserRecord **ret_home) {
         switch (user_record_storage(h)) {
 
         case USER_LUKS:
-                r = home_activate_luks(h, &pkcs11_decrypted_passwords, &new_home);
+                r = home_activate_luks(h, &cache, &new_home);
                 if (r < 0)
                         return r;
 
@@ -656,14 +737,14 @@ static int home_activate(UserRecord *h, UserRecord **ret_home) {
         case USER_SUBVOLUME:
         case USER_DIRECTORY:
         case USER_FSCRYPT:
-                r = home_activate_directory(h, &pkcs11_decrypted_passwords, &new_home);
+                r = home_activate_directory(h, &cache, &new_home);
                 if (r < 0)
                         return r;
 
                 break;
 
         case USER_CIFS:
-                r = home_activate_cifs(h, &pkcs11_decrypted_passwords, &new_home);
+                r = home_activate_cifs(h, &cache, &new_home);
                 if (r < 0)
                         return r;
 
@@ -783,15 +864,16 @@ int home_populate(UserRecord *h, int dir_fd) {
 
 static int user_record_compile_effective_passwords(
                 UserRecord *h,
-                char ***ret_effective_passwords,
-                char ***ret_pkcs11_decrypted_passwords) {
+                PasswordCache *cache,
+                char ***ret_effective_passwords) {
 
-        _cleanup_(strv_free_erasep) char **effective = NULL, **pkcs11_passwords = NULL;
+        _cleanup_(strv_free_erasep) char **effective = NULL;
         size_t n;
         char **i;
         int r;
 
         assert(h);
+        assert(cache);
 
         /* We insist on at least one classic hashed password to be defined in addition to any PKCS#11 one, as
          * a safe fallback, but also to simplify the password changing algorithm: there we require providing
@@ -858,11 +940,37 @@ static int user_record_compile_effective_passwords(
                                 return log_oom();
                 }
 
-                if (ret_pkcs11_decrypted_passwords) {
-                        r = strv_extend(&pkcs11_passwords, data.decrypted_password);
+                r = strv_extend(&cache->pkcs11_passwords, data.decrypted_password);
+                if (r < 0)
+                        return log_oom();
+#else
+                return -EBADSLT;
+#endif
+        }
+
+        for (n = 0; n < h->n_fido2_hmac_salt; n++) {
+#if HAVE_LIBFIDO2
+                _cleanup_(erase_and_freep) char *decrypted_password = NULL;
+
+                r = fido2_use_token(h, h, h->fido2_hmac_salt + n, &decrypted_password);
+                if (r < 0)
+                        return r;
+
+                r = test_password_one(h->fido2_hmac_salt[n].hashed_password, decrypted_password);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to test FIDO2 password: %m");
+                if (r == 0)
+                        return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Decrypted password from token is not correct, refusing.");
+
+                if (ret_effective_passwords) {
+                        r = strv_extend(&effective, decrypted_password);
                         if (r < 0)
                                 return log_oom();
                 }
+
+                r = strv_extend(&cache->fido2_passwords, decrypted_password);
+                if (r < 0)
+                        return log_oom();
 #else
                 return -EBADSLT;
 #endif
@@ -870,8 +978,6 @@ static int user_record_compile_effective_passwords(
 
         if (ret_effective_passwords)
                 *ret_effective_passwords = TAKE_PTR(effective);
-        if (ret_pkcs11_decrypted_passwords)
-                *ret_pkcs11_decrypted_passwords = TAKE_PTR(pkcs11_passwords);
 
         return 0;
 }
@@ -934,8 +1040,9 @@ static int determine_default_storage(UserStorage *ret) {
 }
 
 static int home_create(UserRecord *h, UserRecord **ret_home) {
-        _cleanup_(strv_free_erasep) char **effective_passwords = NULL, **pkcs11_decrypted_passwords = NULL;
+        _cleanup_(strv_free_erasep) char **effective_passwords = NULL;
         _cleanup_(user_record_unrefp) UserRecord *new_home = NULL;
+        _cleanup_(password_cache_free) PasswordCache cache = {};
         UserStorage new_storage = _USER_STORAGE_INVALID;
         const char *new_fs = NULL;
         int r;
@@ -947,7 +1054,7 @@ static int home_create(UserRecord *h, UserRecord **ret_home) {
         if (!uid_is_valid(h->uid))
                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "User record lacks UID, refusing.");
 
-        r = user_record_compile_effective_passwords(h, &effective_passwords, &pkcs11_decrypted_passwords);
+        r = user_record_compile_effective_passwords(h, &cache, &effective_passwords);
         if (r < 0)
                 return r;
 
@@ -996,7 +1103,7 @@ static int home_create(UserRecord *h, UserRecord **ret_home) {
         switch (user_record_storage(h)) {
 
         case USER_LUKS:
-                r = home_create_luks(h, pkcs11_decrypted_passwords, effective_passwords, &new_home);
+                r = home_create_luks(h, &cache, effective_passwords, &new_home);
                 break;
 
         case USER_DIRECTORY:
@@ -1182,15 +1289,15 @@ static int home_validate_update(UserRecord *h, HomeSetup *setup) {
 
 static int home_update(UserRecord *h, UserRecord **ret) {
         _cleanup_(user_record_unrefp) UserRecord *new_home = NULL, *header_home = NULL, *embedded_home = NULL;
-        _cleanup_(strv_free_erasep) char **pkcs11_decrypted_passwords = NULL;
         _cleanup_(home_setup_undo) HomeSetup setup = HOME_SETUP_INIT;
+        _cleanup_(password_cache_free) PasswordCache cache = {};
         bool already_activated = false;
         int r;
 
         assert(h);
         assert(ret);
 
-        r = user_record_authenticate(h, h, &pkcs11_decrypted_passwords, /* strict_verify= */ true);
+        r = user_record_authenticate(h, h, &cache, /* strict_verify= */ true);
         if (r < 0)
                 return r;
         assert(r > 0); /* Insist that a password was verified */
@@ -1201,11 +1308,11 @@ static int home_update(UserRecord *h, UserRecord **ret) {
 
         already_activated = r > 0;
 
-        r = home_prepare(h, already_activated, &pkcs11_decrypted_passwords, &setup, &header_home);
+        r = home_prepare(h, already_activated, &cache, &setup, &header_home);
         if (r < 0)
                 return r;
 
-        r = home_load_embedded_identity(h, setup.root_fd, header_home, USER_RECONCILE_REQUIRE_NEWER, &pkcs11_decrypted_passwords, &embedded_home, &new_home);
+        r = home_load_embedded_identity(h, setup.root_fd, header_home, USER_RECONCILE_REQUIRE_NEWER, &cache, &embedded_home, &new_home);
         if (r < 0)
                 return r;
 
@@ -1237,7 +1344,7 @@ static int home_update(UserRecord *h, UserRecord **ret) {
 
 static int home_resize(UserRecord *h, UserRecord **ret) {
         _cleanup_(home_setup_undo) HomeSetup setup = HOME_SETUP_INIT;
-        _cleanup_(strv_free_erasep) char **pkcs11_decrypted_passwords = NULL;
+        _cleanup_(password_cache_free) PasswordCache cache = {};
         bool already_activated = false;
         int r;
 
@@ -1247,7 +1354,7 @@ static int home_resize(UserRecord *h, UserRecord **ret) {
         if (h->disk_size == UINT64_MAX)
                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "No target size specified, refusing.");
 
-        r = user_record_authenticate(h, h, &pkcs11_decrypted_passwords, /* strict_verify= */ true);
+        r = user_record_authenticate(h, h, &cache, /* strict_verify= */ true);
         if (r < 0)
                 return r;
         assert(r > 0); /* Insist that a password was verified */
@@ -1261,12 +1368,12 @@ static int home_resize(UserRecord *h, UserRecord **ret) {
         switch (user_record_storage(h)) {
 
         case USER_LUKS:
-                return home_resize_luks(h, already_activated, &pkcs11_decrypted_passwords, &setup, ret);
+                return home_resize_luks(h, already_activated, &cache, &setup, ret);
 
         case USER_DIRECTORY:
         case USER_SUBVOLUME:
         case USER_FSCRYPT:
-                return home_resize_directory(h, already_activated, &pkcs11_decrypted_passwords, &setup, ret);
+                return home_resize_directory(h, already_activated, &cache, &setup, ret);
 
         default:
                 return log_error_errno(SYNTHETIC_ERRNO(ENOTTY), "Resizing home directories of type '%s' currently not supported.", user_storage_to_string(user_record_storage(h)));
@@ -1275,8 +1382,9 @@ static int home_resize(UserRecord *h, UserRecord **ret) {
 
 static int home_passwd(UserRecord *h, UserRecord **ret_home) {
         _cleanup_(user_record_unrefp) UserRecord *header_home = NULL, *embedded_home = NULL, *new_home = NULL;
-        _cleanup_(strv_free_erasep) char **effective_passwords = NULL, **pkcs11_decrypted_passwords = NULL;
+        _cleanup_(strv_free_erasep) char **effective_passwords = NULL;
         _cleanup_(home_setup_undo) HomeSetup setup = HOME_SETUP_INIT;
+        _cleanup_(password_cache_free) PasswordCache cache = {};
         bool already_activated = false;
         int r;
 
@@ -1286,7 +1394,7 @@ static int home_passwd(UserRecord *h, UserRecord **ret_home) {
         if (!IN_SET(user_record_storage(h), USER_LUKS, USER_DIRECTORY, USER_SUBVOLUME, USER_FSCRYPT))
                 return log_error_errno(SYNTHETIC_ERRNO(ENOTTY), "Changing password of home directories of type '%s' currently not supported.", user_storage_to_string(user_record_storage(h)));
 
-        r = user_record_compile_effective_passwords(h, &effective_passwords, &pkcs11_decrypted_passwords);
+        r = user_record_compile_effective_passwords(h, &cache, &effective_passwords);
         if (r < 0)
                 return r;
 
@@ -1296,24 +1404,24 @@ static int home_passwd(UserRecord *h, UserRecord **ret_home) {
 
         already_activated = r > 0;
 
-        r = home_prepare(h, already_activated, &pkcs11_decrypted_passwords, &setup, &header_home);
+        r = home_prepare(h, already_activated, &cache, &setup, &header_home);
         if (r < 0)
                 return r;
 
-        r = home_load_embedded_identity(h, setup.root_fd, header_home, USER_RECONCILE_REQUIRE_NEWER_OR_EQUAL, &pkcs11_decrypted_passwords, &embedded_home, &new_home);
+        r = home_load_embedded_identity(h, setup.root_fd, header_home, USER_RECONCILE_REQUIRE_NEWER_OR_EQUAL, &cache, &embedded_home, &new_home);
         if (r < 0)
                 return r;
 
         switch (user_record_storage(h)) {
 
         case USER_LUKS:
-                r = home_passwd_luks(h, &setup, pkcs11_decrypted_passwords, effective_passwords);
+                r = home_passwd_luks(h, &setup, &cache, effective_passwords);
                 if (r < 0)
                         return r;
                 break;
 
         case USER_FSCRYPT:
-                r = home_passwd_fscrypt(h, &setup, pkcs11_decrypted_passwords, effective_passwords);
+                r = home_passwd_fscrypt(h, &setup, &cache, effective_passwords);
                 if (r < 0)
                         return r;
                 break;
@@ -1351,14 +1459,14 @@ static int home_passwd(UserRecord *h, UserRecord **ret_home) {
 static int home_inspect(UserRecord *h, UserRecord **ret_home) {
         _cleanup_(user_record_unrefp) UserRecord *header_home = NULL, *new_home = NULL;
         _cleanup_(home_setup_undo) HomeSetup setup = HOME_SETUP_INIT;
-        _cleanup_(strv_free_erasep) char **pkcs11_decrypted_passwords = NULL;
+        _cleanup_(password_cache_free) PasswordCache cache = {};
         bool already_activated = false;
         int r;
 
         assert(h);
         assert(ret_home);
 
-        r = user_record_authenticate(h, h, &pkcs11_decrypted_passwords, /* strict_verify= */ false);
+        r = user_record_authenticate(h, h, &cache, /* strict_verify= */ false);
         if (r < 0)
                 return r;
 
@@ -1368,11 +1476,11 @@ static int home_inspect(UserRecord *h, UserRecord **ret_home) {
 
         already_activated = r > 0;
 
-        r = home_prepare(h, already_activated, &pkcs11_decrypted_passwords, &setup, &header_home);
+        r = home_prepare(h, already_activated, &cache, &setup, &header_home);
         if (r < 0)
                 return r;
 
-        r = home_load_embedded_identity(h, setup.root_fd, header_home, USER_RECONCILE_ANY, &pkcs11_decrypted_passwords, NULL, &new_home);
+        r = home_load_embedded_identity(h, setup.root_fd, header_home, USER_RECONCILE_ANY, &cache, NULL, &new_home);
         if (r < 0)
                 return r;
 
@@ -1415,7 +1523,7 @@ static int home_lock(UserRecord *h) {
 }
 
 static int home_unlock(UserRecord *h) {
-        _cleanup_(strv_free_erasep) char **pkcs11_decrypted_passwords = NULL;
+        _cleanup_(password_cache_free) PasswordCache cache = {};
         int r;
 
         assert(h);
@@ -1428,11 +1536,11 @@ static int home_unlock(UserRecord *h) {
         /* Note that we don't check if $HOME is actually mounted, since we want to avoid disk accesses on
          * that mount until we have resumed the device. */
 
-        r = user_record_authenticate(h, h, &pkcs11_decrypted_passwords, /* strict_verify= */ false);
+        r = user_record_authenticate(h, h, &cache, /* strict_verify= */ false);
         if (r < 0)
                 return r;
 
-        r = home_unlock_luks(h, &pkcs11_decrypted_passwords);
+        r = home_unlock_luks(h, &cache);
         if (r < 0)
                 return r;
 
@@ -1495,10 +1603,12 @@ static int run(int argc, char *argv[]) {
          * ESOCKTNOSUPPORT → operation not support on this file system
          * ENOKEY          → password incorrect (or not sufficient, or not supplied)
          * EBADSLT         → similar, but PKCS#11 device is defined and might be able to provide password, if it was plugged in which it is not
-         * ENOANO          → suitable PKCS#11 device found, but PIN is missing to unlock it
+         * ENOANO          → suitable PKCS#11/FIDO2 device found, but PIN is missing to unlock it
          * ERFKILL         → suitable PKCS#11 device found, but OK to ask for on-device interactive authentication not given
-         * EOWNERDEAD      → suitable PKCS#11 device found, but its PIN is locked
-         * ENOLCK          → suitable PKCS#11 device found, but PIN incorrect
+         * EMEDIUMTYPE     → suitable FIDO2 device found, but OK to ask for user presence not given
+         * ENOSTR          → suitable FIDO2 device found, but user didn't react to action request on token quickly enough
+         * EOWNERDEAD      → suitable PKCS#11/FIDO2 device found, but its PIN is locked
+         * ENOLCK          → suitable PKCS#11/FIDO2 device found, but PIN incorrect
          * ETOOMANYREFS    → suitable PKCS#11 device found, but PIN incorrect, and only few tries left
          * EUCLEAN         → suitable PKCS#11 device found, but PIN incorrect, and only one try left
          * EBUSY           → file system is currently active

src/home/homework.h

@@ -36,6 +36,14 @@ typedef struct HomeSetup {
         uint64_t partition_size;
 } HomeSetup;
 
+typedef struct PasswordCache {
+        /* Decoding passwords from security tokens is expensive and typically requires user interaction, hence cache any we already figured out. */
+        char **pkcs11_passwords;
+        char **fido2_passwords;
+} PasswordCache;
+
+void password_cache_free(PasswordCache *cache);
+
 #define HOME_SETUP_INIT                                 \
         {                                               \
                 .root_fd = -1,                          \
@@ -46,16 +54,16 @@ typedef struct HomeSetup {
 
 int home_setup_undo(HomeSetup *setup);
 
-int home_prepare(UserRecord *h, bool already_activated, char ***pkcs11_decrypted_passwords, HomeSetup *setup, UserRecord **ret_header_home);
+int home_prepare(UserRecord *h, bool already_activated, PasswordCache *cache, HomeSetup *setup, UserRecord **ret_header_home);
 
-int home_refresh(UserRecord *h, HomeSetup *setup, UserRecord *header_home, char ***pkcs11_decrypted_passwords, struct statfs *ret_statfs, UserRecord **ret_new_home);
+int home_refresh(UserRecord *h, HomeSetup *setup, UserRecord *header_home, PasswordCache *cache, struct statfs *ret_statfs, UserRecord **ret_new_home);
 
 int home_populate(UserRecord *h, int dir_fd);
 
-int home_load_embedded_identity(UserRecord *h, int root_fd, UserRecord *header_home, UserReconcileMode mode, char ***pkcs11_decrypted_passwords, UserRecord **ret_embedded_home, UserRecord **ret_new_home);
+int home_load_embedded_identity(UserRecord *h, int root_fd, UserRecord *header_home, UserReconcileMode mode, PasswordCache *cache, UserRecord **ret_embedded_home, UserRecord **ret_new_home);
 int home_store_embedded_identity(UserRecord *h, int root_fd, uid_t uid, UserRecord *old_home);
 int home_extend_embedded_identity(UserRecord *h, UserRecord *used, HomeSetup *setup);
 
-int user_record_authenticate(UserRecord *h, UserRecord *secret, char ***pkcs11_decrypted_passwords, bool strict_verify);
+int user_record_authenticate(UserRecord *h, UserRecord *secret, PasswordCache *cache, bool strict_verify);
 
 int home_sync_and_statfs(int root_fd, struct statfs *ret);

src/home/meson.build

@@ -14,6 +14,7 @@ systemd_homework_sources = files('''
         homework-mount.c
         homework-mount.h
         homework-pkcs11.h
+        homework-fido2.h
         homework-quota.c
         homework-quota.h
         homework.c
@@ -25,6 +26,9 @@ systemd_homework_sources = files('''
 if conf.get('HAVE_P11KIT') == 1
         systemd_homework_sources += files('homework-pkcs11.c')
 endif
+if conf.get('HAVE_LIBFIDO2') == 1
+        systemd_homework_sources += files('homework-fido2.c')
+endif
 
 systemd_homed_sources = files('''
         home-util.c

src/home/pam_systemd_home.c

@@ -375,6 +375,16 @@ static int handle_generic_user_record_error(
                         return PAM_SERVICE_ERR;
                 }
 
+        } else if (sd_bus_error_has_name(error, BUS_ERROR_TOKEN_USER_PRESENCE_NEEDED)) {
+
+                (void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Please verify presence on security token of user %s.", user_name);
+
+                r = user_record_set_fido2_user_presence_permitted(secret, true);
+                if (r < 0) {
+                        pam_syslog(handle, LOG_ERR, "Failed to set FIDO2 user presence permitted flag: %s", strerror_safe(r));
+                        return PAM_SERVICE_ERR;
+                }
+
         } else if (sd_bus_error_has_name(error, BUS_ERROR_TOKEN_BAD_PIN)) {
                 _cleanup_(erase_and_freep) char *newp = NULL;
 

src/home/user-record-util.c

@@ -980,6 +980,34 @@ int user_record_set_pkcs11_protected_authentication_path_permitted(UserRecord *h
         return 0;
 }
 
+int user_record_set_fido2_user_presence_permitted(UserRecord *h, int b) {
+        _cleanup_(json_variant_unrefp) JsonVariant *w = NULL;
+        int r;
+
+        assert(h);
+
+        w = json_variant_ref(json_variant_by_key(h->json, "secret"));
+
+        if (b < 0)
+                r = json_variant_filter(&w, STRV_MAKE("fido2UserPresencePermitted"));
+        else
+                r = json_variant_set_field_boolean(&w, "fido2UserPresencePermitted", b);
+        if (r < 0)
+                return r;
+
+        if (json_variant_is_blank_object(w))
+                r = json_variant_filter(&h->json, STRV_MAKE("secret"));
+        else
+                r = json_variant_set_field(&h->json, "secret", w);
+        if (r < 0)
+                return r;
+
+        h->fido2_user_presence_permitted = b;
+
+        SET_FLAG(h->mask, USER_RECORD_SECRET, !json_variant_is_blank_object(w));
+        return 0;
+}
+
 static bool per_machine_entry_empty(JsonVariant *v) {
         const char *k;
         _unused_ JsonVariant *e;
@@ -1067,7 +1095,17 @@ int user_record_merge_secret(UserRecord *h, UserRecord *secret) {
                 return r;
 
         if (secret->pkcs11_protected_authentication_path_permitted >= 0) {
-                r = user_record_set_pkcs11_protected_authentication_path_permitted(h, secret->pkcs11_protected_authentication_path_permitted);
+                r = user_record_set_pkcs11_protected_authentication_path_permitted(
+                                h,
+                                secret->pkcs11_protected_authentication_path_permitted);
+                if (r < 0)
+                        return r;
+        }
+
+        if (secret->fido2_user_presence_permitted >= 0) {
+                r = user_record_set_fido2_user_presence_permitted(
+                                h,
+                                secret->fido2_user_presence_permitted);
                 if (r < 0)
                         return r;
         }

src/home/user-record-util.h

@@ -49,6 +49,7 @@ int user_record_make_hashed_password(UserRecord *h, char **password, bool extend
 int user_record_set_hashed_password(UserRecord *h, char **hashed_password);
 int user_record_set_token_pin(UserRecord *h, char **pin, bool prepend);
 int user_record_set_pkcs11_protected_authentication_path_permitted(UserRecord *h, int b);
+int user_record_set_fido2_user_presence_permitted(UserRecord *h, int b);
 int user_record_set_password_change_now(UserRecord *h, int b);
 int user_record_merge_secret(UserRecord *h, UserRecord *secret);
 int user_record_good_authentication(UserRecord *h);

src/libsystemd/sd-bus/bus-common-errors.c

@@ -120,6 +120,8 @@ BUS_ERROR_MAP_ELF_REGISTER const sd_bus_error_map bus_common_errors[] = {
         SD_BUS_ERROR_MAP(BUS_ERROR_BAD_PASSWORD_AND_NO_TOKEN,    EBADSLT),
         SD_BUS_ERROR_MAP(BUS_ERROR_TOKEN_PIN_NEEDED,             ENOANO),
         SD_BUS_ERROR_MAP(BUS_ERROR_TOKEN_PROTECTED_AUTHENTICATION_PATH_NEEDED, ERFKILL),
+        SD_BUS_ERROR_MAP(BUS_ERROR_TOKEN_USER_PRESENCE_NEEDED,   EMEDIUMTYPE),
+        SD_BUS_ERROR_MAP(BUS_ERROR_TOKEN_ACTION_TIMEOUT,         ENOSTR),
         SD_BUS_ERROR_MAP(BUS_ERROR_TOKEN_PIN_LOCKED,             EOWNERDEAD),
         SD_BUS_ERROR_MAP(BUS_ERROR_TOKEN_BAD_PIN,                ENOLCK),
         SD_BUS_ERROR_MAP(BUS_ERROR_TOKEN_BAD_PIN_FEW_TRIES_LEFT, ETOOMANYREFS),

src/libsystemd/sd-bus/bus-common-errors.h

@@ -100,6 +100,8 @@
 #define BUS_ERROR_BAD_PASSWORD_AND_NO_TOKEN "org.freedesktop.home1.BadPasswordAndNoToken"
 #define BUS_ERROR_TOKEN_PIN_NEEDED "org.freedesktop.home1.TokenPinNeeded"
 #define BUS_ERROR_TOKEN_PROTECTED_AUTHENTICATION_PATH_NEEDED "org.freedesktop.home1.TokenProtectedAuthenticationPathNeeded"
+#define BUS_ERROR_TOKEN_USER_PRESENCE_NEEDED "org.freedesktop.home1.TokenUserPresenceNeeded"
+#define BUS_ERROR_TOKEN_ACTION_TIMEOUT "org.freedesktop.home1.TokenActionTimeout"
 #define BUS_ERROR_TOKEN_PIN_LOCKED "org.freedesktop.home1.TokenPinLocked"
 #define BUS_ERROR_TOKEN_BAD_PIN "org.freedesktop.home1.BadPin"
 #define BUS_ERROR_TOKEN_BAD_PIN_FEW_TRIES_LEFT "org.freedesktop.home1.BadPinFewTriesLeft"

src/shared/user-record.c

@@ -81,6 +81,7 @@ UserRecord* user_record_new(void) {
                 .password_change_inactive_usec = UINT64_MAX,
                 .password_change_now = -1,
                 .pkcs11_protected_authentication_path_permitted = -1,
+                .fido2_user_presence_permitted = -1,
         };
 
         return h;
@@ -644,6 +645,7 @@ static int dispatch_secret(const char *name, JsonVariant *variant, JsonDispatchF
                 { "tokenPin",                                   _JSON_VARIANT_TYPE_INVALID, json_dispatch_strv,     offsetof(UserRecord, token_pin),                                      0 },
                 { "pkcs11Pin",   /* legacy alias */             _JSON_VARIANT_TYPE_INVALID, json_dispatch_strv,     offsetof(UserRecord, token_pin),                                      0 },
                 { "pkcs11ProtectedAuthenticationPathPermitted", JSON_VARIANT_BOOLEAN,       json_dispatch_tristate, offsetof(UserRecord, pkcs11_protected_authentication_path_permitted), 0 },
+                { "fido2UserPresencePermitted",                 JSON_VARIANT_BOOLEAN,       json_dispatch_tristate, offsetof(UserRecord, fido2_user_presence_permitted),                  0 },
                 {},
         };
 

src/shared/user-record.h

@@ -330,6 +330,7 @@ typedef struct UserRecord {
         size_t n_fido2_hmac_credential;
         Fido2HmacSalt *fido2_hmac_salt;
         size_t n_fido2_hmac_salt;
+        int fido2_user_presence_permitted;
 
         JsonVariant *json;
 } UserRecord;