--- /dev/null
+/* 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;
+}
projects / thirdparty / systemd.git / blobdiff