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-rw-r--r--fuzz/fuzz_cred.c482
1 files changed, 482 insertions, 0 deletions
diff --git a/fuzz/fuzz_cred.c b/fuzz/fuzz_cred.c
new file mode 100644
index 0000000..a0866dc
--- /dev/null
+++ b/fuzz/fuzz_cred.c
@@ -0,0 +1,482 @@
+/*
+ * Copyright (c) 2019-2022 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 <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "mutator_aux.h"
+#include "wiredata_fido2.h"
+#include "wiredata_u2f.h"
+#include "dummy.h"
+
+#include "../openbsd-compat/openbsd-compat.h"
+
+/* Parameter set defining a FIDO2 make credential operation. */
+struct param {
+ char pin[MAXSTR];
+ char rp_id[MAXSTR];
+ char rp_name[MAXSTR];
+ char user_icon[MAXSTR];
+ char user_name[MAXSTR];
+ char user_nick[MAXSTR];
+ int ext;
+ int seed;
+ struct blob cdh;
+ struct blob excl_cred;
+ struct blob user_id;
+ struct blob wire_data;
+ uint8_t excl_count;
+ uint8_t rk;
+ uint8_t type;
+ uint8_t opt;
+ uint8_t uv;
+};
+
+/*
+ * Collection of HID reports from an authenticator issued with a FIDO2
+ * make credential using the example parameters above.
+ */
+static const uint8_t dummy_wire_data_fido[] = {
+ WIREDATA_CTAP_INIT,
+ WIREDATA_CTAP_CBOR_INFO,
+ WIREDATA_CTAP_CBOR_AUTHKEY,
+ WIREDATA_CTAP_CBOR_PINTOKEN,
+ WIREDATA_CTAP_KEEPALIVE,
+ WIREDATA_CTAP_KEEPALIVE,
+ WIREDATA_CTAP_KEEPALIVE,
+ WIREDATA_CTAP_CBOR_CRED,
+};
+
+/*
+ * Collection of HID reports from an authenticator issued with a U2F
+ * registration using the example parameters above.
+ */
+static const uint8_t dummy_wire_data_u2f[] = {
+ WIREDATA_CTAP_INIT,
+ WIREDATA_CTAP_U2F_6985,
+ WIREDATA_CTAP_U2F_6985,
+ WIREDATA_CTAP_U2F_6985,
+ WIREDATA_CTAP_U2F_6985,
+ WIREDATA_CTAP_U2F_6985,
+ WIREDATA_CTAP_U2F_REGISTER,
+};
+
+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) != 17 ||
+ (v = cbor_array_handle(item)) == NULL)
+ goto fail;
+
+ if (unpack_byte(v[0], &p->rk) < 0 ||
+ unpack_byte(v[1], &p->type) < 0 ||
+ unpack_byte(v[2], &p->opt) < 0 ||
+ unpack_byte(v[3], &p->uv) < 0 ||
+ unpack_byte(v[4], &p->excl_count) < 0 ||
+ unpack_int(v[5], &p->ext) < 0 ||
+ unpack_int(v[6], &p->seed) < 0 ||
+ unpack_string(v[7], p->pin) < 0 ||
+ unpack_string(v[8], p->rp_id) < 0 ||
+ unpack_string(v[9], p->rp_name) < 0 ||
+ unpack_string(v[10], p->user_icon) < 0 ||
+ unpack_string(v[11], p->user_name) < 0 ||
+ unpack_string(v[12], p->user_nick) < 0 ||
+ unpack_blob(v[13], &p->cdh) < 0 ||
+ unpack_blob(v[14], &p->user_id) < 0 ||
+ unpack_blob(v[15], &p->wire_data) < 0 ||
+ unpack_blob(v[16], &p->excl_cred) < 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[17], *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(17)) == NULL ||
+ (argv[0] = pack_byte(p->rk)) == NULL ||
+ (argv[1] = pack_byte(p->type)) == NULL ||
+ (argv[2] = pack_byte(p->opt)) == NULL ||
+ (argv[3] = pack_byte(p->uv)) == NULL ||
+ (argv[4] = pack_byte(p->excl_count)) == NULL ||
+ (argv[5] = pack_int(p->ext)) == NULL ||
+ (argv[6] = pack_int(p->seed)) == NULL ||
+ (argv[7] = pack_string(p->pin)) == NULL ||
+ (argv[8] = pack_string(p->rp_id)) == NULL ||
+ (argv[9] = pack_string(p->rp_name)) == NULL ||
+ (argv[10] = pack_string(p->user_icon)) == NULL ||
+ (argv[11] = pack_string(p->user_name)) == NULL ||
+ (argv[12] = pack_string(p->user_nick)) == NULL ||
+ (argv[13] = pack_blob(&p->cdh)) == NULL ||
+ (argv[14] = pack_blob(&p->user_id)) == NULL ||
+ (argv[15] = pack_blob(&p->wire_data)) == NULL ||
+ (argv[16] = pack_blob(&p->excl_cred)) == NULL)
+ goto fail;
+
+ for (size_t i = 0; i < 17; 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 < 17; 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.type = 1;
+ dummy.ext = FIDO_EXT_HMAC_SECRET;
+
+ strlcpy(dummy.pin, dummy_pin, sizeof(dummy.pin));
+ strlcpy(dummy.rp_id, dummy_rp_id, sizeof(dummy.rp_id));
+ strlcpy(dummy.rp_name, dummy_rp_name, sizeof(dummy.rp_name));
+ strlcpy(dummy.user_icon, dummy_user_icon, sizeof(dummy.user_icon));
+ strlcpy(dummy.user_name, dummy_user_name, sizeof(dummy.user_name));
+ strlcpy(dummy.user_nick, dummy_user_nick, sizeof(dummy.user_nick));
+
+ dummy.cdh.len = sizeof(dummy_cdh);
+ dummy.user_id.len = sizeof(dummy_user_id);
+ dummy.wire_data.len = sizeof(dummy_wire_data_fido);
+
+ memcpy(&dummy.cdh.body, &dummy_cdh, dummy.cdh.len);
+ memcpy(&dummy.user_id.body, &dummy_user_id, dummy.user_id.len);
+ memcpy(&dummy.wire_data.body, &dummy_wire_data_fido,
+ dummy.wire_data.len);
+
+ assert((blob_len = pack(blob, sizeof(blob), &dummy)) != 0);
+
+ if (blob_len > len) {
+ memcpy(ptr, blob, len);
+ return len;
+ }
+
+ memcpy(ptr, blob, blob_len);
+
+ return blob_len;
+}
+
+static void
+make_cred(fido_cred_t *cred, uint8_t opt, int type, const struct blob *cdh,
+ const char *rp_id, const char *rp_name, const struct blob *user_id,
+ const char *user_name, const char *user_nick, const char *user_icon,
+ int ext, uint8_t rk, uint8_t uv, const char *pin, uint8_t excl_count,
+ const struct blob *excl_cred)
+{
+ fido_dev_t *dev;
+
+ if ((dev = open_dev(opt & 2)) == NULL)
+ return;
+ if (opt & 1)
+ fido_dev_force_u2f(dev);
+
+ for (uint8_t i = 0; i < excl_count; i++)
+ fido_cred_exclude(cred, excl_cred->body, excl_cred->len);
+
+ fido_cred_set_type(cred, type);
+ fido_cred_set_clientdata_hash(cred, cdh->body, cdh->len);
+ fido_cred_set_rp(cred, rp_id, rp_name);
+ fido_cred_set_user(cred, user_id->body, user_id->len, user_name,
+ user_nick, user_icon);
+
+ if (ext & FIDO_EXT_HMAC_SECRET)
+ fido_cred_set_extensions(cred, FIDO_EXT_HMAC_SECRET);
+ if (ext & FIDO_EXT_CRED_BLOB)
+ fido_cred_set_blob(cred, user_id->body, user_id->len);
+ if (ext & FIDO_EXT_LARGEBLOB_KEY)
+ fido_cred_set_extensions(cred, FIDO_EXT_LARGEBLOB_KEY);
+ if (ext & FIDO_EXT_MINPINLEN)
+ fido_cred_set_pin_minlen(cred, strlen(pin));
+
+ if (rk & 1)
+ fido_cred_set_rk(cred, FIDO_OPT_TRUE);
+ if (uv & 1)
+ fido_cred_set_uv(cred, FIDO_OPT_TRUE);
+ if (user_id->len)
+ fido_cred_set_prot(cred, user_id->body[0] & 0x03);
+
+ /* repeat memory operations to trigger reallocation paths */
+ fido_cred_set_type(cred, type);
+ fido_cred_set_clientdata_hash(cred, cdh->body, cdh->len);
+ fido_cred_set_rp(cred, rp_id, rp_name);
+ fido_cred_set_user(cred, user_id->body, user_id->len, user_name,
+ user_nick, user_icon);
+
+ if (strlen(pin) == 0)
+ pin = NULL;
+
+ fido_dev_make_cred(dev, cred, (opt & 1) ? NULL : pin);
+
+ fido_dev_cancel(dev);
+ fido_dev_close(dev);
+ fido_dev_free(&dev);
+}
+
+static void
+verify_cred(int type, const unsigned char *cdh_ptr, size_t cdh_len,
+ const char *rp_id, const char *rp_name, const unsigned char *authdata_ptr,
+ size_t authdata_len, const unsigned char *authdata_raw_ptr,
+ size_t authdata_raw_len, int ext, uint8_t rk, uint8_t uv,
+ const unsigned char *x5c_ptr, size_t x5c_len, const unsigned char *sig_ptr,
+ size_t sig_len, const unsigned char *attstmt_ptr, size_t attstmt_len,
+ const char *fmt, int prot, size_t minpinlen)
+{
+ fido_cred_t *cred;
+ uint8_t flags;
+ uint32_t sigcount;
+ int r;
+
+ if ((cred = fido_cred_new()) == NULL)
+ return;
+
+ fido_cred_set_type(cred, type);
+ fido_cred_set_clientdata_hash(cred, cdh_ptr, cdh_len);
+ fido_cred_set_rp(cred, rp_id, rp_name);
+ consume(authdata_ptr, authdata_len);
+ consume(authdata_raw_ptr, authdata_raw_len);
+ consume(x5c_ptr, x5c_len);
+ consume(sig_ptr, sig_len);
+ consume(attstmt_ptr, attstmt_len);
+ if (fido_cred_set_authdata(cred, authdata_ptr, authdata_len) != FIDO_OK)
+ fido_cred_set_authdata_raw(cred, authdata_raw_ptr,
+ authdata_raw_len);
+ fido_cred_set_extensions(cred, ext);
+ if (fido_cred_set_attstmt(cred, attstmt_ptr, attstmt_len) != FIDO_OK) {
+ fido_cred_set_x509(cred, x5c_ptr, x5c_len);
+ fido_cred_set_sig(cred, sig_ptr, sig_len);
+ }
+ fido_cred_set_prot(cred, prot);
+ fido_cred_set_pin_minlen(cred, minpinlen);
+
+ if (rk & 1)
+ fido_cred_set_rk(cred, FIDO_OPT_TRUE);
+ if (uv & 1)
+ fido_cred_set_uv(cred, FIDO_OPT_TRUE);
+ if (fmt)
+ fido_cred_set_fmt(cred, fmt);
+
+ /* repeat memory operations to trigger reallocation paths */
+ if (fido_cred_set_authdata(cred, authdata_ptr, authdata_len) != FIDO_OK)
+ fido_cred_set_authdata_raw(cred, authdata_raw_ptr,
+ authdata_raw_len);
+ if (fido_cred_set_attstmt(cred, attstmt_ptr, attstmt_len) != FIDO_OK) {
+ fido_cred_set_x509(cred, x5c_ptr, x5c_len);
+ fido_cred_set_sig(cred, sig_ptr, sig_len);
+ }
+ fido_cred_set_x509(cred, x5c_ptr, x5c_len);
+ fido_cred_set_sig(cred, sig_ptr, sig_len);
+
+ r = fido_cred_verify(cred);
+ consume(&r, sizeof(r));
+ r = fido_cred_verify_self(cred);
+ consume(&r, sizeof(r));
+
+ consume(fido_cred_pubkey_ptr(cred), fido_cred_pubkey_len(cred));
+ consume(fido_cred_id_ptr(cred), fido_cred_id_len(cred));
+ consume(fido_cred_aaguid_ptr(cred), fido_cred_aaguid_len(cred));
+ consume(fido_cred_user_id_ptr(cred), fido_cred_user_id_len(cred));
+ consume_str(fido_cred_user_name(cred));
+ consume_str(fido_cred_display_name(cred));
+ consume(fido_cred_largeblob_key_ptr(cred),
+ fido_cred_largeblob_key_len(cred));
+
+ flags = fido_cred_flags(cred);
+ consume(&flags, sizeof(flags));
+ sigcount = fido_cred_sigcount(cred);
+ consume(&sigcount, sizeof(sigcount));
+ type = fido_cred_type(cred);
+ consume(&type, sizeof(type));
+ minpinlen = fido_cred_pin_minlen(cred);
+ consume(&minpinlen, sizeof(minpinlen));
+
+ fido_cred_free(&cred);
+}
+
+static void
+test_cred(const struct param *p)
+{
+ fido_cred_t *cred = NULL;
+ int cose_alg = 0;
+
+ if ((cred = fido_cred_new()) == NULL)
+ return;
+
+ switch (p->type & 3) {
+ case 0:
+ cose_alg = COSE_ES256;
+ break;
+ case 1:
+ cose_alg = COSE_RS256;
+ break;
+ case 2:
+ cose_alg = COSE_ES384;
+ break;
+ default:
+ cose_alg = COSE_EDDSA;
+ break;
+ }
+
+ set_wire_data(p->wire_data.body, p->wire_data.len);
+
+ make_cred(cred, p->opt, cose_alg, &p->cdh, p->rp_id, p->rp_name,
+ &p->user_id, p->user_name, p->user_nick, p->user_icon, p->ext,
+ p->rk, p->uv, p->pin, p->excl_count, &p->excl_cred);
+
+ verify_cred(cose_alg,
+ fido_cred_clientdata_hash_ptr(cred),
+ fido_cred_clientdata_hash_len(cred), fido_cred_rp_id(cred),
+ fido_cred_rp_name(cred), fido_cred_authdata_ptr(cred),
+ fido_cred_authdata_len(cred), fido_cred_authdata_raw_ptr(cred),
+ fido_cred_authdata_raw_len(cred), p->ext, p->rk, p->uv,
+ fido_cred_x5c_ptr(cred), fido_cred_x5c_len(cred),
+ fido_cred_sig_ptr(cred), fido_cred_sig_len(cred),
+ fido_cred_attstmt_ptr(cred), fido_cred_attstmt_len(cred),
+ fido_cred_fmt(cred), fido_cred_prot(cred),
+ fido_cred_pin_minlen(cred));
+
+ fido_cred_free(&cred);
+}
+
+static void
+test_touch(const struct param *p)
+{
+ fido_dev_t *dev;
+ int r;
+ int touched;
+
+ set_wire_data(p->wire_data.body, p->wire_data.len);
+
+ if ((dev = open_dev(p->opt & 2)) == NULL)
+ return;
+ if (p->opt & 1)
+ fido_dev_force_u2f(dev);
+
+ r = fido_dev_get_touch_begin(dev);
+ consume_str(fido_strerr(r));
+ r = fido_dev_get_touch_status(dev, &touched, -1);
+ consume_str(fido_strerr(r));
+ consume(&touched, sizeof(touched));
+
+ fido_dev_cancel(dev);
+ fido_dev_close(dev);
+ fido_dev_free(&dev);
+}
+
+static void
+test_misc(const struct param *p)
+{
+ fido_cred_t *cred = NULL;
+
+ if ((cred = fido_cred_new()) == NULL)
+ return;
+
+ /* reuse user id as credential id */
+ fido_cred_set_id(cred, p->user_id.body, p->user_id.len);
+ consume(fido_cred_id_ptr(cred), fido_cred_id_len(cred));
+ fido_cred_free(&cred);
+}
+
+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);
+
+ test_cred(p);
+ test_touch(p);
+ test_misc(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_byte(&p->rk);
+ mutate_byte(&p->type);
+ mutate_byte(&p->opt);
+ mutate_byte(&p->uv);
+ mutate_byte(&p->excl_count);
+ mutate_int(&p->ext);
+ mutate_blob(&p->cdh);
+ mutate_blob(&p->user_id);
+ mutate_blob(&p->excl_cred);
+ mutate_string(p->pin);
+ mutate_string(p->user_icon);
+ mutate_string(p->user_name);
+ mutate_string(p->user_nick);
+ mutate_string(p->rp_id);
+ mutate_string(p->rp_name);
+ }
+
+ if (flags & MUTATE_WIREDATA) {
+ if (p->opt & 1) {
+ p->wire_data.len = sizeof(dummy_wire_data_u2f);
+ memcpy(&p->wire_data.body, &dummy_wire_data_u2f,
+ p->wire_data.len);
+ } else {
+ p->wire_data.len = sizeof(dummy_wire_data_fido);
+ memcpy(&p->wire_data.body, &dummy_wire_data_fido,
+ p->wire_data.len);
+ }
+ mutate_blob(&p->wire_data);
+ }
+}