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systemd/src/shared/libfido2-util.c

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include "libfido2-util.h"
#if HAVE_LIBFIDO2
#include "alloc-util.h"
#include "ask-password-api.h"
#include "dlfcn-util.h"
#include "format-table.h"
#include "glyph-util.h"
#include "log.h"
#include "memory-util.h"
#include "random-util.h"
#include "strv.h"
#include "unistd.h"
static void *libfido2_dl = NULL;
int (*sym_fido_assert_allow_cred)(fido_assert_t *, const unsigned char *, size_t) = NULL;
void (*sym_fido_assert_free)(fido_assert_t **) = NULL;
size_t (*sym_fido_assert_hmac_secret_len)(const fido_assert_t *, size_t) = NULL;
const unsigned char* (*sym_fido_assert_hmac_secret_ptr)(const fido_assert_t *, size_t) = NULL;
fido_assert_t* (*sym_fido_assert_new)(void) = NULL;
int (*sym_fido_assert_set_clientdata_hash)(fido_assert_t *, const unsigned char *, size_t) = NULL;
int (*sym_fido_assert_set_extensions)(fido_assert_t *, int) = NULL;
int (*sym_fido_assert_set_hmac_salt)(fido_assert_t *, const unsigned char *, size_t) = NULL;
int (*sym_fido_assert_set_rp)(fido_assert_t *, const char *) = NULL;
int (*sym_fido_assert_set_up)(fido_assert_t *, fido_opt_t) = NULL;
int (*sym_fido_assert_set_uv)(fido_assert_t *, fido_opt_t) = NULL;
size_t (*sym_fido_cbor_info_extensions_len)(const fido_cbor_info_t *) = NULL;
char **(*sym_fido_cbor_info_extensions_ptr)(const fido_cbor_info_t *) = NULL;
void (*sym_fido_cbor_info_free)(fido_cbor_info_t **) = NULL;
fido_cbor_info_t* (*sym_fido_cbor_info_new)(void) = NULL;
size_t (*sym_fido_cbor_info_options_len)(const fido_cbor_info_t *) = NULL;
char** (*sym_fido_cbor_info_options_name_ptr)(const fido_cbor_info_t *) = NULL;
const bool* (*sym_fido_cbor_info_options_value_ptr)(const fido_cbor_info_t *) = NULL;
void (*sym_fido_cred_free)(fido_cred_t **) = NULL;
size_t (*sym_fido_cred_id_len)(const fido_cred_t *) = NULL;
const unsigned char* (*sym_fido_cred_id_ptr)(const fido_cred_t *) = NULL;
fido_cred_t* (*sym_fido_cred_new)(void) = NULL;
int (*sym_fido_cred_set_clientdata_hash)(fido_cred_t *, const unsigned char *, size_t) = NULL;
int (*sym_fido_cred_set_extensions)(fido_cred_t *, int) = NULL;
int (*sym_fido_cred_set_rk)(fido_cred_t *, fido_opt_t) = NULL;
int (*sym_fido_cred_set_rp)(fido_cred_t *, const char *, const char *) = NULL;
int (*sym_fido_cred_set_type)(fido_cred_t *, int) = NULL;
int (*sym_fido_cred_set_user)(fido_cred_t *, const unsigned char *, size_t, const char *, const char *, const char *) = NULL;
int (*sym_fido_cred_set_uv)(fido_cred_t *, fido_opt_t) = NULL;
void (*sym_fido_dev_free)(fido_dev_t **) = NULL;
int (*sym_fido_dev_get_assert)(fido_dev_t *, fido_assert_t *, const char *) = NULL;
int (*sym_fido_dev_get_cbor_info)(fido_dev_t *, fido_cbor_info_t *) = NULL;
void (*sym_fido_dev_info_free)(fido_dev_info_t **, size_t) = NULL;
int (*sym_fido_dev_info_manifest)(fido_dev_info_t *, size_t, size_t *) = NULL;
const char* (*sym_fido_dev_info_manufacturer_string)(const fido_dev_info_t *) = NULL;
const char* (*sym_fido_dev_info_product_string)(const fido_dev_info_t *) = NULL;
fido_dev_info_t* (*sym_fido_dev_info_new)(size_t) = NULL;
const char* (*sym_fido_dev_info_path)(const fido_dev_info_t *) = NULL;
const fido_dev_info_t* (*sym_fido_dev_info_ptr)(const fido_dev_info_t *, size_t) = NULL;
bool (*sym_fido_dev_is_fido2)(const fido_dev_t *) = NULL;
int (*sym_fido_dev_make_cred)(fido_dev_t *, fido_cred_t *, const char *) = NULL;
fido_dev_t* (*sym_fido_dev_new)(void) = NULL;
int (*sym_fido_dev_open)(fido_dev_t *, const char *) = NULL;
int (*sym_fido_dev_close)(fido_dev_t *) = NULL;
const char* (*sym_fido_strerr)(int) = NULL;
int dlopen_libfido2(void) {
return dlopen_many_sym_or_warn(
&libfido2_dl, "libfido2.so.1", LOG_DEBUG,
DLSYM_ARG(fido_assert_allow_cred),
DLSYM_ARG(fido_assert_free),
DLSYM_ARG(fido_assert_hmac_secret_len),
DLSYM_ARG(fido_assert_hmac_secret_ptr),
DLSYM_ARG(fido_assert_new),
DLSYM_ARG(fido_assert_set_clientdata_hash),
DLSYM_ARG(fido_assert_set_extensions),
DLSYM_ARG(fido_assert_set_hmac_salt),
DLSYM_ARG(fido_assert_set_rp),
DLSYM_ARG(fido_assert_set_up),
DLSYM_ARG(fido_assert_set_uv),
DLSYM_ARG(fido_cbor_info_extensions_len),
DLSYM_ARG(fido_cbor_info_extensions_ptr),
DLSYM_ARG(fido_cbor_info_free),
DLSYM_ARG(fido_cbor_info_new),
DLSYM_ARG(fido_cbor_info_options_len),
DLSYM_ARG(fido_cbor_info_options_name_ptr),
DLSYM_ARG(fido_cbor_info_options_value_ptr),
DLSYM_ARG(fido_cred_free),
DLSYM_ARG(fido_cred_id_len),
DLSYM_ARG(fido_cred_id_ptr),
DLSYM_ARG(fido_cred_new),
DLSYM_ARG(fido_cred_set_clientdata_hash),
DLSYM_ARG(fido_cred_set_extensions),
DLSYM_ARG(fido_cred_set_rk),
DLSYM_ARG(fido_cred_set_rp),
DLSYM_ARG(fido_cred_set_type),
DLSYM_ARG(fido_cred_set_user),
DLSYM_ARG(fido_cred_set_uv),
DLSYM_ARG(fido_dev_free),
DLSYM_ARG(fido_dev_get_assert),
DLSYM_ARG(fido_dev_get_cbor_info),
DLSYM_ARG(fido_dev_info_free),
DLSYM_ARG(fido_dev_info_manifest),
DLSYM_ARG(fido_dev_info_manufacturer_string),
DLSYM_ARG(fido_dev_info_new),
DLSYM_ARG(fido_dev_info_path),
DLSYM_ARG(fido_dev_info_product_string),
DLSYM_ARG(fido_dev_info_ptr),
DLSYM_ARG(fido_dev_is_fido2),
DLSYM_ARG(fido_dev_make_cred),
DLSYM_ARG(fido_dev_new),
DLSYM_ARG(fido_dev_open),
DLSYM_ARG(fido_dev_close),
DLSYM_ARG(fido_strerr));
}
static int verify_features(
fido_dev_t *d,
const char *path,
int log_level, /* the log level to use when device is not FIDO2 with hmac-secret */
bool *ret_has_rk,
bool *ret_has_client_pin,
bool *ret_has_up,
bool *ret_has_uv) {
_cleanup_(fido_cbor_info_free_wrapper) fido_cbor_info_t *di = NULL;
bool found_extension = false;
char **e, **o;
const bool *b;
bool has_rk = false, has_client_pin = false, has_up = true, has_uv = false; /* Defaults are per table in 5.4 in FIDO2 spec */
size_t n;
int r;
assert(d);
assert(path);
if (!sym_fido_dev_is_fido2(d))
return log_full_errno(log_level,
SYNTHETIC_ERRNO(ENODEV),
"Specified device %s is not a FIDO2 device.", path);
di = sym_fido_cbor_info_new();
if (!di)
return log_oom();
r = sym_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, sym_fido_strerr(r));
e = sym_fido_cbor_info_extensions_ptr(di);
n = sym_fido_cbor_info_extensions_len(di);
for (size_t i = 0; i < n; i++) {
log_debug("FIDO2 device implements extension: %s", e[i]);
if (streq(e[i], "hmac-secret"))
found_extension = true;
}
o = sym_fido_cbor_info_options_name_ptr(di);
b = sym_fido_cbor_info_options_value_ptr(di);
n = sym_fido_cbor_info_options_len(di);
for (size_t i = 0; i < n; i++) {
log_debug("FIDO2 device implements option %s: %s", o[i], yes_no(b[i]));
if (streq(o[i], "rk"))
has_rk = b[i];
if (streq(o[i], "clientPin"))
has_client_pin = b[i];
if (streq(o[i], "up"))
has_up = b[i];
if (streq(o[i], "uv"))
has_uv = b[i];
}
if (!found_extension)
return log_full_errno(log_level,
SYNTHETIC_ERRNO(ENODEV),
"Specified device %s is a FIDO2 device, but does not support the required HMAC-SECRET extension.", path);
log_debug("Has rk ('Resident Key') support: %s\n"
"Has clientPin support: %s\n"
"Has up ('User Presence') support: %s\n"
"Has uv ('User Verification') support: %s\n",
yes_no(has_rk),
yes_no(has_client_pin),
yes_no(has_up),
yes_no(has_uv));
if (ret_has_rk)
*ret_has_rk = has_rk;
if (ret_has_client_pin)
*ret_has_client_pin = has_client_pin;
if (ret_has_up)
*ret_has_up = has_up;
if (ret_has_uv)
*ret_has_uv = has_uv;
return 0;
}
static int fido2_use_hmac_hash_specific_token(
const char *path,
const char *rp_id,
const void *salt,
size_t salt_size,
const void *cid,
size_t cid_size,
char **pins,
Fido2EnrollFlags required, /* client pin/user presence required */
void **ret_hmac,
size_t *ret_hmac_size) {
_cleanup_(fido_assert_free_wrapper) fido_assert_t *a = NULL;
_cleanup_(fido_dev_free_wrapper) fido_dev_t *d = NULL;
_cleanup_(erase_and_freep) void *hmac_copy = NULL;
bool has_up, has_client_pin, has_uv;
size_t hmac_size;
const void *hmac;
int r;
assert(path);
assert(rp_id);
assert(salt);
assert(cid);
assert(ret_hmac);
assert(ret_hmac_size);
d = sym_fido_dev_new();
if (!d)
return log_oom();
r = sym_fido_dev_open(d, path);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to open FIDO2 device %s: %s", path, sym_fido_strerr(r));
r = verify_features(d, path, LOG_ERR, NULL, &has_client_pin, &has_up, &has_uv);
if (r < 0)
return r;
if (!has_client_pin && FLAGS_SET(required, FIDO2ENROLL_PIN))
return log_error_errno(SYNTHETIC_ERRNO(EHWPOISON),
"PIN required to unlock, but FIDO2 device %s does not support it.",
path);
if (!has_up && FLAGS_SET(required, FIDO2ENROLL_UP))
return log_error_errno(SYNTHETIC_ERRNO(EHWPOISON),
"User presence test required to unlock, but FIDO2 device %s does not support it.",
path);
if (!has_uv && FLAGS_SET(required, FIDO2ENROLL_UV))
return log_error_errno(SYNTHETIC_ERRNO(EHWPOISON),
"User verification required to unlock, but FIDO2 device %s does not support it.",
path);
a = sym_fido_assert_new();
if (!a)
return log_oom();
r = sym_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", sym_fido_strerr(r));
r = sym_fido_assert_set_hmac_salt(a, salt, salt_size);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to set salt on FIDO2 assertion: %s", sym_fido_strerr(r));
r = sym_fido_assert_set_rp(a, rp_id);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to set FIDO2 assertion ID: %s", sym_fido_strerr(r));
r = sym_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", sym_fido_strerr(r));
r = sym_fido_assert_allow_cred(a, cid, cid_size);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to add FIDO2 assertion credential ID: %s", sym_fido_strerr(r));
log_info("Asking FIDO2 token for authentication.");
if (has_up) {
r = sym_fido_assert_set_up(a, FLAGS_SET(required, FIDO2ENROLL_UP) ? FIDO_OPT_TRUE : FIDO_OPT_FALSE);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to %s FIDO2 user presence test: %s",
enable_disable(FLAGS_SET(required, FIDO2ENROLL_UP)),
sym_fido_strerr(r));
if (FLAGS_SET(required, FIDO2ENROLL_UP))
log_notice("%s%sPlease confirm presence on security token to unlock.",
emoji_enabled() ? special_glyph(SPECIAL_GLYPH_TOUCH) : "",
emoji_enabled() ? " " : "");
}
if (has_uv && !FLAGS_SET(required, FIDO2ENROLL_UV_OMIT)) {
r = sym_fido_assert_set_uv(a, FLAGS_SET(required, FIDO2ENROLL_UV) ? FIDO_OPT_TRUE : FIDO_OPT_FALSE);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to %s FIDO2 user verification: %s",
enable_disable(FLAGS_SET(required, FIDO2ENROLL_UV)),
sym_fido_strerr(r));
if (FLAGS_SET(required, FIDO2ENROLL_UV))
log_notice("%s%sPlease verify user on security token to unlock.",
emoji_enabled() ? special_glyph(SPECIAL_GLYPH_TOUCH) : "",
emoji_enabled() ? " " : "");
}
for (;;) {
bool retry_with_up = false, retry_with_pin = false;
if (FLAGS_SET(required, FIDO2ENROLL_PIN)) {
char **i;
/* OK, we need a pin, try with all pins in turn */
if (strv_isempty(pins))
r = FIDO_ERR_PIN_REQUIRED;
else
STRV_FOREACH(i, pins) {
r = sym_fido_dev_get_assert(d, a, *i);
if (r != FIDO_ERR_PIN_INVALID)
break;
}
} else
r = sym_fido_dev_get_assert(d, a, NULL);
/* In some conditions, where a PIN or UP is required we might accept that. Let's check the
* conditions and if so try immediately again. */
switch (r) {
case FIDO_ERR_UP_REQUIRED:
/* So the token asked for "up". Try to turn it on, for compat with systemd 248 and try again. */
if (!has_up)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Token asks for user presence test but doesn't advertise 'up' feature.");
if (FLAGS_SET(required, FIDO2ENROLL_UP))
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Token asks for user presence test but was already enabled.");
if (FLAGS_SET(required, FIDO2ENROLL_UP_IF_NEEDED)) {
log_notice("%s%sPlease confirm presence on security to unlock.",
emoji_enabled() ? special_glyph(SPECIAL_GLYPH_TOUCH) : "",
emoji_enabled() ? " " : "");
retry_with_up = true;
}
break;
case FIDO_ERR_UNSUPPORTED_OPTION:
/* AuthenTrend ATKey.Pro returns this instead of FIDO_ERR_UP_REQUIRED, let's handle
* it gracefully (also see below.) */
if (has_up && (required & (FIDO2ENROLL_UP|FIDO2ENROLL_UP_IF_NEEDED)) == FIDO2ENROLL_UP_IF_NEEDED) {
log_notice("%s%sGot unsupported option error when when user presence test is turned off. Trying with user presence test turned on.",
emoji_enabled() ? special_glyph(SPECIAL_GLYPH_TOUCH) : "",
emoji_enabled() ? " " : "");
retry_with_up = true;
}
break;
case FIDO_ERR_PIN_REQUIRED:
/* A pin was requested. Maybe supply one, if we are configured to do so on request */
if (!has_client_pin)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Token asks for PIN but doesn't advertise 'clientPin' feature.");
if (FLAGS_SET(required, FIDO2ENROLL_PIN) && !strv_isempty(pins))
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Token asks for PIN but one was already supplied.");
if ((required & (FIDO2ENROLL_PIN|FIDO2ENROLL_PIN_IF_NEEDED)) == FIDO2ENROLL_PIN_IF_NEEDED) {
/* If a PIN so far wasn't specified but is requested by the device, and
* FIDO2ENROLL_PIN_IF_NEEDED is set, then provide it */
log_debug("Retrying to create credential with PIN.");
retry_with_pin = true;
}
break;
default:
break;
}
if (!retry_with_up && !retry_with_pin)
break;
if (retry_with_up) {
r = sym_fido_assert_set_up(a, FIDO_OPT_TRUE);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to enable FIDO2 user presence test: %s", sym_fido_strerr(r));
required |= FIDO2ENROLL_UP;
}
if (retry_with_pin)
required |= FIDO2ENROLL_PIN;
}
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.");
#ifdef FIDO_ERR_UV_BLOCKED
case FIDO_ERR_UV_BLOCKED:
return log_error_errno(SYNTHETIC_ERRNO(EOWNERDEAD),
"Verification of security token is blocked, please remove/reinsert token.");
#endif
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", sym_fido_strerr(r));
}
hmac = sym_fido_assert_hmac_secret_ptr(a, 0);
if (!hmac)
return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to retrieve HMAC secret.");
hmac_size = sym_fido_assert_hmac_secret_len(a, 0);
hmac_copy = memdup(hmac, hmac_size);
if (!hmac_copy)
return log_oom();
*ret_hmac = TAKE_PTR(hmac_copy);
*ret_hmac_size = hmac_size;
return 0;
}
int fido2_use_hmac_hash(
const char *device,
const char *rp_id,
const void *salt,
size_t salt_size,
const void *cid,
size_t cid_size,
char **pins,
Fido2EnrollFlags required, /* client pin/user presence required */
void **ret_hmac,
size_t *ret_hmac_size) {
size_t allocated = 64, found = 0;
fido_dev_info_t *di = NULL;
int r;
r = dlopen_libfido2();
if (r < 0)
return log_error_errno(r, "FIDO2 support is not installed.");
if (device)
return fido2_use_hmac_hash_specific_token(device, rp_id, salt, salt_size, cid, cid_size, pins, required, ret_hmac, ret_hmac_size);
di = sym_fido_dev_info_new(allocated);
if (!di)
return log_oom();
r = sym_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", sym_fido_strerr(r));
goto finish;
}
for (size_t i = 0; i < found; i++) {
const fido_dev_info_t *entry;
const char *path;
entry = sym_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 = sym_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_hmac_hash_specific_token(path, rp_id, salt, salt_size, cid, cid_size, pins, required, ret_hmac, ret_hmac_size);
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:
sym_fido_dev_info_free(&di, allocated);
return r;
}
#define FIDO2_SALT_SIZE 32
int fido2_generate_hmac_hash(
const char *device,
const char *rp_id,
const char *rp_name,
const void *user_id, size_t user_id_len,
const char *user_name,
const char *user_display_name,
const char *user_icon,
const char *askpw_icon_name,
Fido2EnrollFlags lock_with,
void **ret_cid, size_t *ret_cid_size,
void **ret_salt, size_t *ret_salt_size,
void **ret_secret, size_t *ret_secret_size,
char **ret_usedpin,
Fido2EnrollFlags *ret_locked_with) {
_cleanup_(erase_and_freep) void *salt = NULL, *secret_copy = NULL;
_cleanup_(fido_assert_free_wrapper) fido_assert_t *a = NULL;
_cleanup_(fido_cred_free_wrapper) fido_cred_t *c = NULL;
_cleanup_(fido_dev_free_wrapper) fido_dev_t *d = NULL;
_cleanup_(erase_and_freep) char *used_pin = NULL;
bool has_rk, has_client_pin, has_up, has_uv;
_cleanup_free_ char *cid_copy = NULL;
size_t cid_size, secret_size;
const void *cid, *secret;
int r;
assert(device);
assert(ret_cid);
assert(ret_cid_size);
assert(ret_salt);
assert(ret_salt_size);
assert(ret_secret);
assert(ret_secret_size);
/* Construction is like this: we generate a salt of 32 bytes. We then ask the FIDO2 device to
* HMAC-SHA256 it for us with its internal key. The result is the key used by LUKS and account
* authentication. LUKS and UNIX password auth all do their own salting before hashing, so that FIDO2
* device never sees the volume key.
*
* S = HMAC-SHA256(I, D)
*
* with: S → LUKS/account authentication key (never stored)
* I → internal key on FIDO2 device (stored in the FIDO2 device)
* D → salt we generate here (stored in the privileged part of the JSON record)
*
*/
assert(device);
assert((lock_with & ~(FIDO2ENROLL_PIN|FIDO2ENROLL_UP|FIDO2ENROLL_UV)) == 0);
r = dlopen_libfido2();
if (r < 0)
return log_error_errno(r, "FIDO2 token support is not installed.");
salt = malloc(FIDO2_SALT_SIZE);
if (!salt)
return log_oom();
r = genuine_random_bytes(salt, FIDO2_SALT_SIZE, RANDOM_BLOCK);
if (r < 0)
return log_error_errno(r, "Failed to generate salt: %m");
d = sym_fido_dev_new();
if (!d)
return log_oom();
r = sym_fido_dev_open(d, device);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to open FIDO2 device %s: %s", device, sym_fido_strerr(r));
r = verify_features(d, device, LOG_ERR, &has_rk, &has_client_pin, &has_up, &has_uv);
if (r < 0)
return r;
/* While enrolling degrade gracefully if the requested feature set isn't available, but let the user know */
if (!has_client_pin && FLAGS_SET(lock_with, FIDO2ENROLL_PIN)) {
log_notice("Requested to lock with PIN, but FIDO2 device %s does not support it, disabling.", device);
lock_with &= ~FIDO2ENROLL_PIN;
}
if (!has_up && FLAGS_SET(lock_with, FIDO2ENROLL_UP)) {
log_notice("Locking with user presence test requested, but FIDO2 device %s does not support it, disabling.", device);
lock_with &= ~FIDO2ENROLL_UP;
}
if (!has_uv && FLAGS_SET(lock_with, FIDO2ENROLL_UV)) {
log_notice("Locking with user verification test requested, but FIDO2 device %s does not support it, disabling.", device);
lock_with &= ~FIDO2ENROLL_UV;
}
c = sym_fido_cred_new();
if (!c)
return log_oom();
r = sym_fido_cred_set_extensions(c, FIDO_EXT_HMAC_SECRET);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to enable HMAC-SECRET extension on FIDO2 credential: %s", sym_fido_strerr(r));
r = sym_fido_cred_set_rp(c, rp_id, rp_name);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to set FIDO2 credential relying party ID/name: %s", sym_fido_strerr(r));
r = sym_fido_cred_set_type(c, COSE_ES256);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to set FIDO2 credential type to ES256: %s", sym_fido_strerr(r));
r = sym_fido_cred_set_user(
c,
user_id, user_id_len,
user_name,
user_display_name,
user_icon);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to set FIDO2 credential user data: %s", sym_fido_strerr(r));
r = sym_fido_cred_set_clientdata_hash(c, (const unsigned char[32]) {}, 32);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to set FIDO2 client data hash: %s", sym_fido_strerr(r));
if (has_rk) {
r = sym_fido_cred_set_rk(c, FIDO_OPT_FALSE);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to turn off FIDO2 resident key option of credential: %s", sym_fido_strerr(r));
}
if (has_uv) {
r = sym_fido_cred_set_uv(c, FIDO_OPT_FALSE);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to turn off FIDO2 user verification option of credential: %s", sym_fido_strerr(r));
}
/* As per specification "up" is assumed to be implicit when making credentials, hence we don't
* explicitly enable/disable it here */
log_info("Initializing FIDO2 credential on security token.");
if (has_uv || has_up)
log_notice("%s%s(Hint: This might require confirmation of user presence on security token.)",
emoji_enabled() ? special_glyph(SPECIAL_GLYPH_TOUCH) : "",
emoji_enabled() ? " " : "");
r = sym_fido_dev_make_cred(d, c, NULL);
if (r == FIDO_ERR_PIN_REQUIRED) {
if (!has_client_pin)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Token asks for PIN but doesn't advertise 'clientPin' feature.");
for (;;) {
_cleanup_(strv_free_erasep) char **pin = NULL;
char **i;
r = ask_password_auto("Please enter security token PIN:", askpw_icon_name, NULL, "fido2-pin", "fido2-pin", USEC_INFINITY, 0, &pin);
if (r < 0)
return log_error_errno(r, "Failed to acquire user PIN: %m");
r = FIDO_ERR_PIN_INVALID;
STRV_FOREACH(i, pin) {
if (isempty(*i)) {
log_notice("PIN may not be empty.");
continue;
}
r = sym_fido_dev_make_cred(d, c, *i);
if (r == FIDO_OK) {
used_pin = strdup(*i);
if (!used_pin)
return log_oom();
break;
}
if (r != FIDO_ERR_PIN_INVALID)
break;
}
if (r != FIDO_ERR_PIN_INVALID)
break;
log_notice("PIN incorrect, please try again.");
}
}
if (r == FIDO_ERR_PIN_AUTH_BLOCKED)
return log_notice_errno(SYNTHETIC_ERRNO(EPERM),
"Token PIN is currently blocked, please remove and reinsert token.");
#ifdef FIDO_ERR_UV_BLOCKED
if (r == FIDO_ERR_UV_BLOCKED)
return log_notice_errno(SYNTHETIC_ERRNO(EPERM),
"Token verification is currently blocked, please remove and reinsert token.");
#endif
if (r == FIDO_ERR_ACTION_TIMEOUT)
return log_error_errno(SYNTHETIC_ERRNO(ENOSTR),
"Token action timeout. (User didn't interact with token quickly enough.)");
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to generate FIDO2 credential: %s", sym_fido_strerr(r));
cid = sym_fido_cred_id_ptr(c);
if (!cid)
return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to get FIDO2 credential ID.");
cid_size = sym_fido_cred_id_len(c);
a = sym_fido_assert_new();
if (!a)
return log_oom();
r = sym_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", sym_fido_strerr(r));
r = sym_fido_assert_set_hmac_salt(a, salt, FIDO2_SALT_SIZE);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to set salt on FIDO2 assertion: %s", sym_fido_strerr(r));
r = sym_fido_assert_set_rp(a, rp_id);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to set FIDO2 assertion ID: %s", sym_fido_strerr(r));
r = sym_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", sym_fido_strerr(r));
r = sym_fido_assert_allow_cred(a, cid, cid_size);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to add FIDO2 assertion credential ID: %s", sym_fido_strerr(r));
log_info("Generating secret key on FIDO2 security token.");
if (has_up) {
r = sym_fido_assert_set_up(a, FLAGS_SET(lock_with, FIDO2ENROLL_UP) ? FIDO_OPT_TRUE : FIDO_OPT_FALSE);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to %s FIDO2 user presence test: %s",
enable_disable(FLAGS_SET(lock_with, FIDO2ENROLL_UP)),
sym_fido_strerr(r));
if (FLAGS_SET(lock_with, FIDO2ENROLL_UP))
log_notice("%s%sIn order to allow secret key generation, please confirm presence on security token.",
emoji_enabled() ? special_glyph(SPECIAL_GLYPH_TOUCH) : "",
emoji_enabled() ? " " : "");
}
if (has_uv) {
r = sym_fido_assert_set_uv(a, FLAGS_SET(lock_with, FIDO2ENROLL_UV) ? FIDO_OPT_TRUE : FIDO_OPT_FALSE);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to %s FIDO user verification: %s",
enable_disable(FLAGS_SET(lock_with, FIDO2ENROLL_UV)),
sym_fido_strerr(r));
if (FLAGS_SET(lock_with, FIDO2ENROLL_UV))
log_notice("%s%sIn order to allow secret key generation, please verify user on security token.",
emoji_enabled() ? special_glyph(SPECIAL_GLYPH_TOUCH) : "",
emoji_enabled() ? " " : "");
}
for (;;) {
bool retry_with_up = false, retry_with_pin = false;
r = sym_fido_dev_get_assert(d, a, FLAGS_SET(lock_with, FIDO2ENROLL_PIN) ? used_pin : NULL);
switch (r) {
case FIDO_ERR_UP_REQUIRED:
/* If the token asks for "up" when we turn off, then this might be a feature that
* isn't optional. Let's enable it */
if (!has_up)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Token asks for user presence test but doesn't advertise 'up' feature.");
if (FLAGS_SET(lock_with, FIDO2ENROLL_UP))
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Token asks for user presence test but was already enabled.");
log_notice("%s%sLocking without user presence test requested, but FIDO2 device %s requires it, enabling.",
emoji_enabled() ? special_glyph(SPECIAL_GLYPH_TOUCH) : "",
emoji_enabled() ? " " : "",
device);
retry_with_up = true;
break;
case FIDO_ERR_UNSUPPORTED_OPTION:
/* AuthenTrend ATKey.Pro says it supports "up", but if we disable it it will fail
* with FIDO_ERR_UNSUPPORTED_OPTION, probably because it isn't actually
* optional. Let's see if turning it on works. This is very similar to the
* FIDO_ERR_UP_REQUIRED case, but since the error is so vague we implement it
* slightly more defensively. */
if (has_up && !FLAGS_SET(lock_with, FIDO2ENROLL_UP)) {
log_notice("%s%sGot unsupported option error when when user presence test is turned off. Trying with user presence test turned on.",
emoji_enabled() ? special_glyph(SPECIAL_GLYPH_TOUCH) : "",
emoji_enabled() ? " " : "");
retry_with_up = true;
}
break;
case FIDO_ERR_PIN_REQUIRED:
if (!has_client_pin)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Token asks for client PIN check but doesn't advertise 'clientPin' feature.");
if (FLAGS_SET(lock_with, FIDO2ENROLL_PIN))
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Token asks for user client PIN check but was already enabled.");
log_debug("Token requires PIN for assertion, enabling.");
retry_with_pin = true;
break;
default:
break;
}
if (!retry_with_up && !retry_with_pin)
break;
if (retry_with_up) {
r = sym_fido_assert_set_up(a, FIDO_OPT_TRUE);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to enable FIDO2 user presence test: %s", sym_fido_strerr(r));
lock_with |= FIDO2ENROLL_UP;
}
if (retry_with_pin)
lock_with |= FIDO2ENROLL_PIN;
}
if (r == FIDO_ERR_ACTION_TIMEOUT)
return log_error_errno(SYNTHETIC_ERRNO(ENOSTR),
"Token action timeout. (User didn't interact with token quickly enough.)");
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to ask token for assertion: %s", sym_fido_strerr(r));
secret = sym_fido_assert_hmac_secret_ptr(a, 0);
if (!secret)
return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to retrieve HMAC secret.");
secret_size = sym_fido_assert_hmac_secret_len(a, 0);
secret_copy = memdup(secret, secret_size);
if (!secret_copy)
return log_oom();
cid_copy = memdup(cid, cid_size);
if (!cid_copy)
return log_oom();
*ret_cid = TAKE_PTR(cid_copy);
*ret_cid_size = cid_size;
*ret_salt = TAKE_PTR(salt);
*ret_salt_size = FIDO2_SALT_SIZE;
*ret_secret = TAKE_PTR(secret_copy);
*ret_secret_size = secret_size;
if (ret_usedpin)
*ret_usedpin = TAKE_PTR(used_pin);
if (ret_locked_with)
*ret_locked_with = lock_with;
return 0;
}
#endif
#if HAVE_LIBFIDO2
static int check_device_is_fido2_with_hmac_secret(const char *path) {
_cleanup_(fido_dev_free_wrapper) fido_dev_t *d = NULL;
int r;
d = sym_fido_dev_new();
if (!d)
return log_oom();
r = sym_fido_dev_open(d, path);
if (r != FIDO_OK)
return log_error_errno(SYNTHETIC_ERRNO(EIO),
"Failed to open FIDO2 device %s: %s", path, sym_fido_strerr(r));
r = verify_features(d, path, LOG_DEBUG, NULL, NULL, NULL, NULL);
if (r == -ENODEV) /* Not a FIDO2 device, or not implementing 'hmac-secret' */
return false;
if (r < 0)
return r;
return true;
}
#endif
int fido2_list_devices(void) {
#if HAVE_LIBFIDO2
_cleanup_(table_unrefp) Table *t = NULL;
size_t allocated = 64, found = 0;
fido_dev_info_t *di = NULL;
int r;
r = dlopen_libfido2();
if (r < 0)
return log_error_errno(r, "FIDO2 token support is not installed.");
di = sym_fido_dev_info_new(allocated);
if (!di)
return log_oom();
r = sym_fido_dev_info_manifest(di, allocated, &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. */
log_info("No FIDO2 devices found.");
r = 0;
goto finish;
}
if (r != FIDO_OK) {
r = log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to enumerate FIDO2 devices: %s", sym_fido_strerr(r));
goto finish;
}
t = table_new("path", "manufacturer", "product");
if (!t) {
r = log_oom();
goto finish;
}
for (size_t i = 0; i < found; i++) {
const fido_dev_info_t *entry;
entry = sym_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;
}
r = check_device_is_fido2_with_hmac_secret(sym_fido_dev_info_path(entry));
if (r < 0)
goto finish;
if (!r)
continue;
r = table_add_many(
t,
TABLE_PATH, sym_fido_dev_info_path(entry),
TABLE_STRING, sym_fido_dev_info_manufacturer_string(entry),
TABLE_STRING, sym_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:
sym_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 fido2_find_device_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;
r = dlopen_libfido2();
if (r < 0)
return log_error_errno(r, "FIDO2 token support is not installed.");
di = sym_fido_dev_info_new(di_size);
if (!di)
return log_oom();
r = sym_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 FIDO devices found.");
goto finish;
}
if (r != FIDO_OK) {
r = log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to enumerate FIDO devices: %s", sym_fido_strerr(r));
goto finish;
}
if (found > 1) {
r = log_error_errno(SYNTHETIC_ERRNO(ENOTUNIQ), "More than one FIDO device found.");
goto finish;
}
entry = sym_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;
}
r = check_device_is_fido2_with_hmac_secret(sym_fido_dev_info_path(entry));
if (r < 0)
goto finish;
if (!r) {
r = log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "FIDO device discovered does not implement FIDO2 with 'hmac-secret' extension.");
goto finish;
}
path = sym_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:
sym_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
}
int fido2_have_device(const char *device) {
#if HAVE_LIBFIDO2
size_t allocated = 64, found = 0;
fido_dev_info_t *di = NULL;
int r;
/* Return == 0 if not devices are found, > 0 if at least one is found */
r = dlopen_libfido2();
if (r < 0)
return log_error_errno(r, "FIDO2 support is not installed.");
if (device) {
if (access(device, F_OK) < 0) {
if (errno == ENOENT)
return 0;
return log_error_errno(errno, "Failed to determine whether device '%s' exists: %m", device);
}
return 1;
}
di = sym_fido_dev_info_new(allocated);
if (!di)
return log_oom();
r = sym_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 = 0;
goto finish;
}
if (r != FIDO_OK) {
r = log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to enumerate FIDO2 devices: %s", sym_fido_strerr(r));
goto finish;
}
r = found;
finish:
sym_fido_dev_info_free(&di, allocated);
return r;
#else
return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
"FIDO2 tokens not supported on this build.");
#endif
}
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