1 files changed, 239 insertions, 0 deletions
diff --git a/fuzz/fuzz_hid.c b/fuzz/fuzz_hid.c
new file mode 100644
index 0000000..27ccb2f
--- /dev/null
+++ b/fuzz/fuzz_hid.c
@@ -0,0 +1,239 @@
+/*
+ * Copyright (c) 2020-2021 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 <assert.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "../openbsd-compat/openbsd-compat.h"
+#include "mutator_aux.h"
+#include "dummy.h"
+
+extern int fido_hid_get_usage(const uint8_t *, size_t, uint32_t *);
+extern int fido_hid_get_report_len(const uint8_t *, size_t, size_t *, size_t *);
+extern void set_udev_parameters(const char *, const struct blob *);
+
+struct param {
+	int seed;
+	char uevent[MAXSTR];
+	struct blob report_descriptor;
+	struct blob netlink_wiredata;
+};
+
+/*
+ * Sample HID report descriptor from the FIDO HID interface of a YubiKey 5.
+ */
+static const uint8_t dummy_report_descriptor[] = {
+	0x06, 0xd0, 0xf1, 0x09, 0x01, 0xa1, 0x01, 0x09,
+	0x20, 0x15, 0x00, 0x26, 0xff, 0x00, 0x75, 0x08,
+	0x95, 0x40, 0x81, 0x02, 0x09, 0x21, 0x15, 0x00,
+	0x26, 0xff, 0x00, 0x75, 0x08, 0x95, 0x40, 0x91,
+	0x02, 0xc0
+};
+
+/*
+ * Sample uevent file from a Yubico Security Key.
+ */
+static const char dummy_uevent[] =
+	"DRIVER=hid-generic\n"
+	"HID_ID=0003:00001050:00000120\n"
+	"HID_NAME=Yubico Security Key by Yubico\n"
+	"HID_PHYS=usb-0000:00:14.0-3/input0\n"
+	"HID_UNIQ=\n"
+	"MODALIAS=hid:b0003g0001v00001050p00000120\n";
+
+struct param *
+unpack(const uint8_t *ptr, size_t len)
+{
+	cbor_item_t *item = NULL, **v;
+	struct cbor_load_result cbor;
+	struct param *p;
+	int ok = -1;
+
+	if ((p = calloc(1, sizeof(*p))) == NULL ||
+	    (item = cbor_load(ptr, len, &cbor)) == NULL ||
+	    cbor.read != len ||
+	    cbor_isa_array(item) == false ||
+	    cbor_array_is_definite(item) == false ||
+	    cbor_array_size(item) != 4 ||
+	    (v = cbor_array_handle(item)) == NULL)
+		goto fail;
+
+	if (unpack_int(v[0], &p->seed) < 0 ||
+	    unpack_string(v[1], p->uevent) < 0 ||
+	    unpack_blob(v[2], &p->report_descriptor) < 0 ||
+	    unpack_blob(v[3], &p->netlink_wiredata) < 0)
+		goto fail;
+
+	ok = 0;
+fail:
+	if (ok < 0) {
+		free(p);
+		p = NULL;
+	}
+
+	if (item)
+		cbor_decref(&item);
+
+	return p;
+}
+
+size_t
+pack(uint8_t *ptr, size_t len, const struct param *p)
+{
+	cbor_item_t *argv[4], *array = NULL;
+	size_t cbor_alloc_len, cbor_len = 0;
+	unsigned char *cbor = NULL;
+
+	memset(argv, 0, sizeof(argv));
+
+	if ((array = cbor_new_definite_array(4)) == NULL ||
+	    (argv[0] = pack_int(p->seed)) == NULL ||
+	    (argv[1] = pack_string(p->uevent)) == NULL ||
+	    (argv[2] = pack_blob(&p->report_descriptor)) == NULL ||
+	    (argv[3] = pack_blob(&p->netlink_wiredata)) == NULL)
+		goto fail;
+
+	for (size_t i = 0; i < 4; i++)
+		if (cbor_array_push(array, argv[i]) == false)
+			goto fail;
+
+	if ((cbor_len = cbor_serialize_alloc(array, &cbor,
+	    &cbor_alloc_len)) > len) {
+		cbor_len = 0;
+		goto fail;
+	}
+
+	memcpy(ptr, cbor, cbor_len);
+fail:
+	for (size_t i = 0; i < 4; i++)
+		if (argv[i])
+			cbor_decref(&argv[i]);
+
+	if (array)
+		cbor_decref(&array);
+
+	free(cbor);
+
+	return cbor_len;
+}
+
+size_t
+pack_dummy(uint8_t *ptr, size_t len)
+{
+	struct param dummy;
+	uint8_t	blob[MAXCORPUS];
+	size_t blob_len;
+
+	memset(&dummy, 0, sizeof(dummy));
+
+	dummy.report_descriptor.len = sizeof(dummy_report_descriptor);
+	strlcpy(dummy.uevent, dummy_uevent, sizeof(dummy.uevent));
+	memcpy(&dummy.report_descriptor.body, &dummy_report_descriptor,
+	    dummy.report_descriptor.len);
+	dummy.netlink_wiredata.len = sizeof(dummy_netlink_wiredata);
+	memcpy(&dummy.netlink_wiredata.body, &dummy_netlink_wiredata,
+	    dummy.netlink_wiredata.len);
+
+	assert((blob_len = pack(blob, sizeof(blob), &dummy)) != 0);
+	if (blob_len > len)
+		blob_len = len;
+
+	memcpy(ptr, blob, blob_len);
+
+	return blob_len;
+}
+
+static void
+get_usage(const struct param *p)
+{
+	uint32_t usage_page = 0;
+
+	fido_hid_get_usage(p->report_descriptor.body, p->report_descriptor.len,
+	    &usage_page);
+	consume(&usage_page, sizeof(usage_page));
+}
+
+static void
+get_report_len(const struct param *p)
+{
+	size_t report_in_len = 0;
+	size_t report_out_len = 0;
+
+	fido_hid_get_report_len(p->report_descriptor.body,
+	    p->report_descriptor.len, &report_in_len, &report_out_len);
+	consume(&report_in_len, sizeof(report_in_len));
+	consume(&report_out_len, sizeof(report_out_len));
+}
+
+static void
+manifest(const struct param *p)
+{
+	size_t ndevs, nfound;
+	fido_dev_info_t *devlist = NULL, *devlist_set = NULL;
+	int16_t vendor_id, product_id;
+	fido_dev_io_t io;
+	fido_dev_transport_t t;
+
+	memset(&io, 0, sizeof(io));
+	memset(&t, 0, sizeof(t));
+	set_netlink_io_functions(fd_read, fd_write);
+	set_wire_data(p->netlink_wiredata.body, p->netlink_wiredata.len);
+	set_udev_parameters(p->uevent, &p->report_descriptor);
+
+	ndevs = uniform_random(64);
+	if ((devlist = fido_dev_info_new(ndevs)) == NULL ||
+	    (devlist_set = fido_dev_info_new(1)) == NULL ||
+	    fido_dev_info_manifest(devlist, ndevs, &nfound) != FIDO_OK)
+		goto out;
+	for (size_t i = 0; i < nfound; i++) {
+		const fido_dev_info_t *di = fido_dev_info_ptr(devlist, i);
+		consume_str(fido_dev_info_path(di));
+		consume_str(fido_dev_info_manufacturer_string(di));
+		consume_str(fido_dev_info_product_string(di));
+		vendor_id = fido_dev_info_vendor(di);
+		product_id = fido_dev_info_product(di);
+		consume(&vendor_id, sizeof(vendor_id));
+		consume(&product_id, sizeof(product_id));
+		fido_dev_info_set(devlist_set, 0, fido_dev_info_path(di),
+		    fido_dev_info_manufacturer_string(di),
+		    fido_dev_info_product_string(di), &io, &t);
+	}
+out:
+	fido_dev_info_free(&devlist, ndevs);
+	fido_dev_info_free(&devlist_set, 1);
+}
+
+void
+test(const struct param *p)
+{
+	prng_init((unsigned int)p->seed);
+	fuzz_clock_reset();
+	fido_init(FIDO_DEBUG);
+	fido_set_log_handler(consume_str);
+
+	get_usage(p);
+	get_report_len(p);
+	manifest(p);
+}
+
+void
+mutate(struct param *p, unsigned int seed, unsigned int flags) NO_MSAN
+{
+	if (flags & MUTATE_SEED)
+		p->seed = (int)seed;
+
+	if (flags & MUTATE_PARAM) {
+		mutate_blob(&p->report_descriptor);
+		mutate_string(p->uevent);
+	}
+
+	if (flags & MUTATE_WIREDATA)
+		mutate_blob(&p->netlink_wiredata);
+}