1 files changed, 328 insertions, 0 deletions
diff --git a/tools/assert_get.c b/tools/assert_get.c
new file mode 100644
index 0000000..32d40b1
--- /dev/null
+++ b/tools/assert_get.c
@@ -0,0 +1,328 @@
+/*
+ * Copyright (c) 2018-2023 Yubico AB. All rights reserved.
+ * Use of this source code is governed by a BSD-style
+ * license that can be found in the LICENSE file.
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <fido.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#include "../openbsd-compat/openbsd-compat.h"
+#include "extern.h"
+
+struct toggle {
+	fido_opt_t up;
+	fido_opt_t uv;
+	fido_opt_t pin;
+};
+
+static const char *
+opt2str(fido_opt_t v)
+{
+	switch (v) {
+	case FIDO_OPT_OMIT:
+		return "omit";
+	case FIDO_OPT_TRUE:
+		return "true";
+	case FIDO_OPT_FALSE:
+		return "false";
+	default:
+		return "unknown";
+	}
+}
+
+static void
+parse_toggle(const char *str, struct toggle *opt)
+{
+	fido_opt_t *k;
+	fido_opt_t  v;
+	char *assignment;
+	char *key;
+	char *val;
+
+	if ((assignment = strdup(str)) == NULL)
+		err(1, "strdup");
+	if ((val = strchr(assignment, '=')) == NULL)
+		errx(1, "invalid assignment '%s'", assignment);
+
+	key = assignment;
+	*val++ = '\0';
+
+	if (!strcmp(val, "true"))
+		v = FIDO_OPT_TRUE;
+	else if (!strcmp(val, "false"))
+		v = FIDO_OPT_FALSE;
+	else
+		errx(1, "unknown value '%s'", val);
+
+	if (!strcmp(key, "up"))
+		k = &opt->up;
+	else if (!strcmp(key, "uv"))
+		k = &opt->uv;
+	else if (!strcmp(key, "pin"))
+		k = &opt->pin;
+	else
+		errx(1, "unknown key '%s'", key);
+
+	free(assignment);
+
+	*k = v;
+}
+
+static fido_assert_t *
+prepare_assert(FILE *in_f, int flags, const struct toggle *opt)
+{
+	fido_assert_t *assert = NULL;
+	struct blob cdh;
+	struct blob id;
+	struct blob hmac_salt;
+	char *rpid = NULL;
+	int r;
+
+	memset(&cdh, 0, sizeof(cdh));
+	memset(&id, 0, sizeof(id));
+	memset(&hmac_salt, 0, sizeof(hmac_salt));
+
+	r = base64_read(in_f, &cdh);
+	r |= string_read(in_f, &rpid);
+	if ((flags & FLAG_RK) == 0)
+		r |= base64_read(in_f, &id);
+	if (flags & FLAG_HMAC)
+		r |= base64_read(in_f, &hmac_salt);
+	if (r < 0)
+		errx(1, "input error");
+
+	if (flags & FLAG_DEBUG) {
+		fprintf(stderr, "client data%s:\n",
+			flags & FLAG_CD ? "" : " hash");
+		xxd(cdh.ptr, cdh.len);
+		fprintf(stderr, "relying party id: %s\n", rpid);
+		if ((flags & FLAG_RK) == 0) {
+			fprintf(stderr, "credential id:\n");
+			xxd(id.ptr, id.len);
+		}
+		fprintf(stderr, "up=%s\n", opt2str(opt->up));
+		fprintf(stderr, "uv=%s\n", opt2str(opt->uv));
+		fprintf(stderr, "pin=%s\n", opt2str(opt->pin));
+	}
+
+	if ((assert = fido_assert_new()) == NULL)
+		errx(1, "fido_assert_new");
+
+	if (flags & FLAG_CD)
+		r = fido_assert_set_clientdata(assert, cdh.ptr, cdh.len);
+	else
+		r = fido_assert_set_clientdata_hash(assert, cdh.ptr, cdh.len);
+
+	if (r != FIDO_OK || (r = fido_assert_set_rp(assert, rpid)) != FIDO_OK)
+		errx(1, "fido_assert_set: %s", fido_strerr(r));
+	if ((r = fido_assert_set_up(assert, opt->up)) != FIDO_OK)
+		errx(1, "fido_assert_set_up: %s", fido_strerr(r));
+	if ((r = fido_assert_set_uv(assert, opt->uv)) != FIDO_OK)
+		errx(1, "fido_assert_set_uv: %s", fido_strerr(r));
+
+	if (flags & FLAG_HMAC) {
+		if ((r = fido_assert_set_extensions(assert,
+		    FIDO_EXT_HMAC_SECRET)) != FIDO_OK)
+			errx(1, "fido_assert_set_extensions: %s",
+			    fido_strerr(r));
+		if ((r = fido_assert_set_hmac_salt(assert, hmac_salt.ptr,
+		    hmac_salt.len)) != FIDO_OK)
+			errx(1, "fido_assert_set_hmac_salt: %s",
+			    fido_strerr(r));
+	}
+	if (flags & FLAG_LARGEBLOB) {
+		if ((r = fido_assert_set_extensions(assert,
+		    FIDO_EXT_LARGEBLOB_KEY)) != FIDO_OK)
+			errx(1, "fido_assert_set_extensions: %s", fido_strerr(r));
+	}
+	if ((flags & FLAG_RK) == 0) {
+		if ((r = fido_assert_allow_cred(assert, id.ptr,
+		    id.len)) != FIDO_OK)
+			errx(1, "fido_assert_allow_cred: %s", fido_strerr(r));
+	}
+
+	free(hmac_salt.ptr);
+	free(cdh.ptr);
+	free(id.ptr);
+	free(rpid);
+
+	return (assert);
+}
+
+static void
+print_assert(FILE *out_f, const fido_assert_t *assert, size_t idx, int flags)
+{
+	char *cdh = NULL;
+	char *authdata = NULL;
+	char *sig = NULL;
+	char *user_id = NULL;
+	char *hmac_secret = NULL;
+	char *key = NULL;
+	int r;
+
+	r = base64_encode(fido_assert_clientdata_hash_ptr(assert),
+	    fido_assert_clientdata_hash_len(assert), &cdh);
+	r |= base64_encode(fido_assert_authdata_ptr(assert, idx),
+	    fido_assert_authdata_len(assert, 0), &authdata);
+	r |= base64_encode(fido_assert_sig_ptr(assert, idx),
+	    fido_assert_sig_len(assert, idx), &sig);
+	if (flags & FLAG_RK)
+		r |= base64_encode(fido_assert_user_id_ptr(assert, idx),
+		    fido_assert_user_id_len(assert, idx), &user_id);
+	if (flags & FLAG_HMAC)
+		r |= base64_encode(fido_assert_hmac_secret_ptr(assert, idx),
+		    fido_assert_hmac_secret_len(assert, idx), &hmac_secret);
+	if (flags & FLAG_LARGEBLOB)
+		r |= base64_encode(fido_assert_largeblob_key_ptr(assert, idx),
+		    fido_assert_largeblob_key_len(assert, idx), &key);
+	if (r < 0)
+		errx(1, "output error");
+
+	fprintf(out_f, "%s\n", cdh);
+	fprintf(out_f, "%s\n", fido_assert_rp_id(assert));
+	fprintf(out_f, "%s\n", authdata);
+	fprintf(out_f, "%s\n", sig);
+	if (flags & FLAG_RK)
+		fprintf(out_f, "%s\n", user_id);
+	if (hmac_secret) {
+		fprintf(out_f, "%s\n", hmac_secret);
+		explicit_bzero(hmac_secret, strlen(hmac_secret));
+	}
+	if (key) {
+		fprintf(out_f, "%s\n", key);
+		explicit_bzero(key, strlen(key));
+	}
+
+	free(key);
+	free(hmac_secret);
+	free(cdh);
+	free(authdata);
+	free(sig);
+	free(user_id);
+}
+
+int
+assert_get(int argc, char **argv)
+{
+	fido_dev_t *dev = NULL;
+	fido_assert_t *assert = NULL;
+	struct toggle opt;
+	char prompt[1024];
+	char pin[128];
+	char *in_path = NULL;
+	char *out_path = NULL;
+	FILE *in_f = NULL;
+	FILE *out_f = NULL;
+	int flags = 0;
+	int ch;
+	int r;
+
+	opt.up = opt.uv = opt.pin = FIDO_OPT_OMIT;
+
+	while ((ch = getopt(argc, argv, "bdhi:o:prt:uvw")) != -1) {
+		switch (ch) {
+		case 'b':
+			flags |= FLAG_LARGEBLOB;
+			break;
+		case 'd':
+			flags |= FLAG_DEBUG;
+			break;
+		case 'h':
+			flags |= FLAG_HMAC;
+			break;
+		case 'i':
+			in_path = optarg;
+			break;
+		case 'o':
+			out_path = optarg;
+			break;
+		case 'p':
+			opt.up = FIDO_OPT_TRUE;
+			break;
+		case 'r':
+			flags |= FLAG_RK;
+			break;
+		case 't' :
+			parse_toggle(optarg, &opt);
+			break;
+		case 'u':
+			flags |= FLAG_U2F;
+			break;
+		case 'v':
+			/* -v implies both pin and uv for historical reasons */
+			opt.pin = FIDO_OPT_TRUE;
+			opt.uv = FIDO_OPT_TRUE;
+			break;
+		case 'w':
+			flags |= FLAG_CD;
+			break;
+		default:
+			usage();
+		}
+	}
+
+	argc -= optind;
+	argv += optind;
+
+	if (argc < 1)
+		usage();
+
+	in_f = open_read(in_path);
+	out_f = open_write(out_path);
+
+	fido_init((flags & FLAG_DEBUG) ? FIDO_DEBUG : 0);
+
+	assert = prepare_assert(in_f, flags, &opt);
+
+	dev = open_dev(argv[0]);
+	if (flags & FLAG_U2F)
+		fido_dev_force_u2f(dev);
+
+	if (opt.pin == FIDO_OPT_TRUE) {
+		r = snprintf(prompt, sizeof(prompt), "Enter PIN for %s: ",
+		    argv[0]);
+		if (r < 0 || (size_t)r >= sizeof(prompt))
+			errx(1, "snprintf");
+		if (!readpassphrase(prompt, pin, sizeof(pin), RPP_ECHO_OFF))
+			errx(1, "readpassphrase");
+		if (strlen(pin) < 4 || strlen(pin) > 63) {
+			explicit_bzero(pin, sizeof(pin));
+			errx(1, "invalid PIN length");
+		}
+		r = fido_dev_get_assert(dev, assert, pin);
+	} else
+		r = fido_dev_get_assert(dev, assert, NULL);
+
+	explicit_bzero(pin, sizeof(pin));
+
+	if (r != FIDO_OK)
+		errx(1, "fido_dev_get_assert: %s", fido_strerr(r));
+
+	if (flags & FLAG_RK) {
+		for (size_t idx = 0; idx < fido_assert_count(assert); idx++)
+			print_assert(out_f, assert, idx, flags);
+	} else {
+		if (fido_assert_count(assert) != 1)
+			errx(1, "fido_assert_count: %zu",
+			    fido_assert_count(assert));
+		print_assert(out_f, assert, 0, flags);
+	}
+
+	fido_dev_close(dev);
+	fido_dev_free(&dev);
+	fido_assert_free(&assert);
+
+	fclose(in_f);
+	fclose(out_f);
+	in_f = NULL;
+	out_f = NULL;
+
+	exit(0);
+}