fuzz: exercise fido_cred_set_attobj()

Author: LDVG

.actions/fuzz-linux

@@ -88,7 +88,7 @@ mkdir corpus
 curl -s https://storage.googleapis.com/yubico-libfido2/corpus.tgz |
     tar -C corpus -zxf -
 export UBSAN_OPTIONS ASAN_OPTIONS MSAN_OPTIONS
-for f in assert bio cred credman hid largeblob mgmt netlink pcsc; do
+for f in assert attobj bio cred credman hid largeblob mgmt netlink pcsc; do
 	build/fuzz/fuzz_${f} -use_value_profile=1 -reload=30 -print_pcs=1 \
 	    -print_funcs=30 -timeout=10 -runs=1 corpus/fuzz_${f}
 done

fuzz/CMakeLists.txt

@@ -1,4 +1,4 @@
-# Copyright (c) 2019-2023 Yubico AB. All rights reserved.
+# Copyright (c) 2019-2024 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
@@ -80,3 +80,10 @@ set_target_properties(fuzz_pcsc PROPERTIES
 	LINK_FLAGS ${FUZZ_LDFLAGS}
 	LINKER_LANGUAGE ${FUZZ_LINKER_LANGUAGE})
 target_link_libraries(fuzz_pcsc fido2_shared)
+
+# fuzz_attobj
+add_executable(fuzz_attobj fuzz_attobj.c ${COMMON_SOURCES} ${COMPAT_SOURCES})
+set_target_properties(fuzz_attobj PROPERTIES
+	LINK_FLAGS ${FUZZ_LDFLAGS}
+	LINKER_LANGUAGE ${FUZZ_LINKER_LANGUAGE})
+target_link_libraries(fuzz_attobj fido2_shared)

fuzz/fuzz_attobj.c

@@ -0,0 +1,332 @@
+/*
+ * Copyright (c) 2024 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"
+
+struct param {
+	int seed;
+	char rp_id[MAXSTR];
+	struct blob cdh;
+	struct blob attobj;
+	uint8_t type;
+};
+
+static const uint8_t dummy_attestation_object[] = {
+	0xa3, 0x63, 0x66, 0x6d, 0x74, 0x66, 0x70, 0x61,
+	0x63, 0x6b, 0x65, 0x64, 0x67, 0x61, 0x74, 0x74,
+	0x53, 0x74, 0x6d, 0x74, 0xa3, 0x63, 0x61, 0x6c,
+	0x67, 0x26, 0x63, 0x73, 0x69, 0x67, 0x58, 0x46,
+	0x30, 0x44, 0x02, 0x20, 0x54, 0x92, 0x28, 0x3b,
+	0x83, 0x33, 0x47, 0x56, 0x68, 0x79, 0xb2, 0x0c,
+	0x84, 0x80, 0xcc, 0x67, 0x27, 0x8b, 0xfa, 0x48,
+	0x43, 0x0d, 0x3c, 0xb4, 0x02, 0x36, 0x87, 0x97,
+	0x3e, 0xdf, 0x2f, 0x65, 0x02, 0x20, 0x1b, 0x56,
+	0x17, 0x06, 0xe2, 0x26, 0x0f, 0x6a, 0xe9, 0xa9,
+	0x70, 0x99, 0x62, 0xeb, 0x3a, 0x04, 0x1a, 0xc4,
+	0xa7, 0x03, 0x28, 0x56, 0x7c, 0xed, 0x47, 0x08,
+	0x68, 0x73, 0x6a, 0xb6, 0x89, 0x0d, 0x63, 0x78,
+	0x35, 0x63, 0x81, 0x59, 0x02, 0xe6, 0x30, 0x82,
+	0x02, 0xe2, 0x30, 0x81, 0xcb, 0x02, 0x01, 0x01,
+	0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86,
+	0xf7, 0x0d, 0x01, 0x01, 0x0b, 0x05, 0x00, 0x30,
+	0x1d, 0x31, 0x1b, 0x30, 0x19, 0x06, 0x03, 0x55,
+	0x04, 0x03, 0x13, 0x12, 0x59, 0x75, 0x62, 0x69,
+	0x63, 0x6f, 0x20, 0x55, 0x32, 0x46, 0x20, 0x54,
+	0x65, 0x73, 0x74, 0x20, 0x43, 0x41, 0x30, 0x1e,
+	0x17, 0x0d, 0x31, 0x34, 0x30, 0x35, 0x31, 0x35,
+	0x31, 0x32, 0x35, 0x38, 0x35, 0x34, 0x5a, 0x17,
+	0x0d, 0x31, 0x34, 0x30, 0x36, 0x31, 0x34, 0x31,
+	0x32, 0x35, 0x38, 0x35, 0x34, 0x5a, 0x30, 0x1d,
+	0x31, 0x1b, 0x30, 0x19, 0x06, 0x03, 0x55, 0x04,
+	0x03, 0x13, 0x12, 0x59, 0x75, 0x62, 0x69, 0x63,
+	0x6f, 0x20, 0x55, 0x32, 0x46, 0x20, 0x54, 0x65,
+	0x73, 0x74, 0x20, 0x45, 0x45, 0x30, 0x59, 0x30,
+	0x13, 0x06, 0x07, 0x2a, 0x86, 0x48, 0xce, 0x3d,
+	0x02, 0x01, 0x06, 0x08, 0x2a, 0x86, 0x48, 0xce,
+	0x3d, 0x03, 0x01, 0x07, 0x03, 0x42, 0x00, 0x04,
+	0xdb, 0x0a, 0xdb, 0xf5, 0x21, 0xc7, 0x5c, 0xce,
+	0x63, 0xdc, 0xa6, 0xe1, 0xe8, 0x25, 0x06, 0x0d,
+	0x94, 0xe6, 0x27, 0x54, 0x19, 0x4f, 0x9d, 0x24,
+	0xaf, 0x26, 0x1a, 0xbe, 0xad, 0x99, 0x44, 0x1f,
+	0x95, 0xa3, 0x71, 0x91, 0x0a, 0x3a, 0x20, 0xe7,
+	0x3e, 0x91, 0x5e, 0x13, 0xe8, 0xbe, 0x38, 0x05,
+	0x7a, 0xd5, 0x7a, 0xa3, 0x7e, 0x76, 0x90, 0x8f,
+	0xaf, 0xe2, 0x8a, 0x94, 0xb6, 0x30, 0xeb, 0x9d,
+	0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86,
+	0xf7, 0x0d, 0x01, 0x01, 0x0b, 0x05, 0x00, 0x03,
+	0x82, 0x02, 0x01, 0x00, 0x95, 0x40, 0x6b, 0x50,
+	0x61, 0x7d, 0xad, 0x84, 0xa3, 0xb4, 0xeb, 0x88,
+	0x0f, 0xe3, 0x30, 0x0f, 0x2d, 0xa2, 0x0a, 0x00,
+	0xd9, 0x25, 0x04, 0xee, 0x72, 0xfa, 0x67, 0xdf,
+	0x58, 0x51, 0x0f, 0x0b, 0x47, 0x02, 0x9c, 0x3e,
+	0x41, 0x29, 0x4a, 0x93, 0xac, 0x29, 0x85, 0x89,
+	0x2d, 0xa4, 0x7a, 0x81, 0x32, 0x28, 0x57, 0x71,
+	0x01, 0xef, 0xa8, 0x42, 0x88, 0x16, 0x96, 0x37,
+	0x91, 0xd5, 0xdf, 0xe0, 0x8f, 0xc9, 0x3c, 0x8d,
+	0xb0, 0xcd, 0x89, 0x70, 0x82, 0xec, 0x79, 0xd3,
+	0xc6, 0x78, 0x73, 0x29, 0x32, 0xe5, 0xab, 0x6c,
+	0xbd, 0x56, 0x9f, 0xd5, 0x45, 0x91, 0xce, 0xc1,
+	0xdd, 0x8d, 0x64, 0xdc, 0xe9, 0x9c, 0x1f, 0x5e,
+	0x3c, 0xd2, 0xaf, 0x51, 0xa5, 0x82, 0x18, 0xaf,
+	0xe0, 0x37, 0xe7, 0x32, 0x9e, 0x76, 0x05, 0x77,
+	0x02, 0x7b, 0xe6, 0x24, 0xa0, 0x31, 0x56, 0x1b,
+	0xfd, 0x19, 0xc5, 0x71, 0xd3, 0xf0, 0x9e, 0xc0,
+	0x73, 0x05, 0x4e, 0xbc, 0x85, 0xb8, 0x53, 0x9e,
+	0xef, 0xc5, 0xbc, 0x9c, 0x56, 0xa3, 0xba, 0xd9,
+	0x27, 0x6a, 0xbb, 0xa9, 0x7a, 0x40, 0xd7, 0x47,
+	0x8b, 0x55, 0x72, 0x6b, 0xe3, 0xfe, 0x28, 0x49,
+	0x71, 0x24, 0xf4, 0x8f, 0xf4, 0x20, 0x81, 0xea,
+	0x38, 0xff, 0x7c, 0x0a, 0x4f, 0xdf, 0x02, 0x82,
+	0x39, 0x81, 0x82, 0x3b, 0xca, 0x09, 0xdd, 0xca,
+	0xaa, 0x0f, 0x27, 0xf5, 0xa4, 0x83, 0x55, 0x6c,
+	0x9a, 0x39, 0x9b, 0x15, 0x3a, 0x16, 0x63, 0xdc,
+	0x5b, 0xf9, 0xac, 0x5b, 0xbc, 0xf7, 0x9f, 0xbe,
+	0x0f, 0x8a, 0xa2, 0x3c, 0x31, 0x13, 0xa3, 0x32,
+	0x48, 0xca, 0x58, 0x87, 0xf8, 0x7b, 0xa0, 0xa1,
+	0x0a, 0x6a, 0x60, 0x96, 0x93, 0x5f, 0x5d, 0x26,
+	0x9e, 0x63, 0x1d, 0x09, 0xae, 0x9a, 0x41, 0xe5,
+	0xbd, 0x08, 0x47, 0xfe, 0xe5, 0x09, 0x9b, 0x20,
+	0xfd, 0x12, 0xe2, 0xe6, 0x40, 0x7f, 0xba, 0x4a,
+	0x61, 0x33, 0x66, 0x0d, 0x0e, 0x73, 0xdb, 0xb0,
+	0xd5, 0xa2, 0x9a, 0x9a, 0x17, 0x0d, 0x34, 0x30,
+	0x85, 0x6a, 0x42, 0x46, 0x9e, 0xff, 0x34, 0x8f,
+	0x5f, 0x87, 0x6c, 0x35, 0xe7, 0xa8, 0x4d, 0x35,
+	0xeb, 0xc1, 0x41, 0xaa, 0x8a, 0xd2, 0xda, 0x19,
+	0xaa, 0x79, 0xa2, 0x5f, 0x35, 0x2c, 0xa0, 0xfd,
+	0x25, 0xd3, 0xf7, 0x9d, 0x25, 0x18, 0x2d, 0xfa,
+	0xb4, 0xbc, 0xbb, 0x07, 0x34, 0x3c, 0x8d, 0x81,
+	0xbd, 0xf4, 0xe9, 0x37, 0xdb, 0x39, 0xe9, 0xd1,
+	0x45, 0x5b, 0x20, 0x41, 0x2f, 0x2d, 0x27, 0x22,
+	0xdc, 0x92, 0x74, 0x8a, 0x92, 0xd5, 0x83, 0xfd,
+	0x09, 0xfb, 0x13, 0x9b, 0xe3, 0x39, 0x7a, 0x6b,
+	0x5c, 0xfa, 0xe6, 0x76, 0x9e, 0xe0, 0xe4, 0xe3,
+	0xef, 0xad, 0xbc, 0xfd, 0x42, 0x45, 0x9a, 0xd4,
+	0x94, 0xd1, 0x7e, 0x8d, 0xa7, 0xd8, 0x05, 0xd5,
+	0xd3, 0x62, 0xcf, 0x15, 0xcf, 0x94, 0x7d, 0x1f,
+	0x5b, 0x58, 0x20, 0x44, 0x20, 0x90, 0x71, 0xbe,
+	0x66, 0xe9, 0x9a, 0xab, 0x74, 0x32, 0x70, 0x53,
+	0x1d, 0x69, 0xed, 0x87, 0x66, 0xf4, 0x09, 0x4f,
+	0xca, 0x25, 0x30, 0xc2, 0x63, 0x79, 0x00, 0x3c,
+	0xb1, 0x9b, 0x39, 0x3f, 0x00, 0xe0, 0xa8, 0x88,
+	0xef, 0x7a, 0x51, 0x5b, 0xe7, 0xbd, 0x49, 0x64,
+	0xda, 0x41, 0x7b, 0x24, 0xc3, 0x71, 0x22, 0xfd,
+	0xd1, 0xd1, 0x20, 0xb3, 0x3f, 0x97, 0xd3, 0x97,
+	0xb2, 0xaa, 0x18, 0x1c, 0x9e, 0x03, 0x77, 0x7b,
+	0x5b, 0x7e, 0xf9, 0xa3, 0xa0, 0xd6, 0x20, 0x81,
+	0x2c, 0x38, 0x8f, 0x9d, 0x25, 0xde, 0xe9, 0xc8,
+	0xf5, 0xdd, 0x6a, 0x47, 0x9c, 0x65, 0x04, 0x5a,
+	0x56, 0xe6, 0xc2, 0xeb, 0xf2, 0x02, 0x97, 0xe1,
+	0xb9, 0xd8, 0xe1, 0x24, 0x76, 0x9f, 0x23, 0x62,
+	0x39, 0x03, 0x4b, 0xc8, 0xf7, 0x34, 0x07, 0x49,
+	0xd6, 0xe7, 0x4d, 0x9a, 0x68, 0x61, 0x75, 0x74,
+	0x68, 0x44, 0x61, 0x74, 0x61, 0x58, 0xc4, 0x49,
+	0x96, 0x0d, 0xe5, 0x88, 0x0e, 0x8c, 0x68, 0x74,
+	0x34, 0x17, 0x0f, 0x64, 0x76, 0x60, 0x5b, 0x8f,
+	0xe4, 0xae, 0xb9, 0xa2, 0x86, 0x32, 0xc7, 0x99,
+	0x5c, 0xf3, 0xba, 0x83, 0x1d, 0x97, 0x63, 0x41,
+	0x00, 0x00, 0x00, 0x00, 0xf8, 0xa0, 0x11, 0xf3,
+	0x8c, 0x0a, 0x4d, 0x15, 0x80, 0x06, 0x17, 0x11,
+	0x1f, 0x9e, 0xdc, 0x7d, 0x00, 0x40, 0x53, 0xfb,
+	0xdf, 0xaa, 0xce, 0x63, 0xde, 0xc5, 0xfe, 0x47,
+	0xe6, 0x52, 0xeb, 0xf3, 0x5d, 0x53, 0xa8, 0xbf,
+	0x9d, 0xd6, 0x09, 0x6b, 0x5e, 0x7f, 0xe0, 0x0d,
+	0x51, 0x30, 0x85, 0x6a, 0xda, 0x68, 0x70, 0x85,
+	0xb0, 0xdb, 0x08, 0x0b, 0x83, 0x2c, 0xef, 0x44,
+	0xe2, 0x36, 0x88, 0xee, 0x76, 0x90, 0x6e, 0x7b,
+	0x50, 0x3e, 0x9a, 0xa0, 0xd6, 0x3c, 0x34, 0xe3,
+	0x83, 0xe7, 0xd1, 0xbd, 0x9f, 0x25, 0xa5, 0x01,
+	0x02, 0x03, 0x26, 0x20, 0x01, 0x21, 0x58, 0x20,
+	0x17, 0x5b, 0x27, 0xa6, 0x56, 0xb2, 0x26, 0x0c,
+	0x26, 0x0c, 0x55, 0x42, 0x78, 0x17, 0x5d, 0x4c,
+	0xf8, 0xa2, 0xfd, 0x1b, 0xb9, 0x54, 0xdf, 0xd5,
+	0xeb, 0xbf, 0x22, 0x64, 0xf5, 0x21, 0x9a, 0xc6,
+	0x22, 0x58, 0x20, 0x87, 0x5f, 0x90, 0xe6, 0xfd,
+	0x71, 0x27, 0x9f, 0xeb, 0xe3, 0x03, 0x44, 0xbc,
+	0x8d, 0x49, 0xc6, 0x1c, 0x31, 0x3b, 0x72, 0xae,
+	0xd4, 0x53, 0xb1, 0xfe, 0x5d, 0xe1, 0x30, 0xfc,
+	0x2b, 0x1e, 0xd2
+};
+
+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) != 5 ||
+	    (v = cbor_array_handle(item)) == NULL)
+		goto fail;
+
+	if (unpack_int(v[0], &p->seed) < 0 ||
+	    unpack_string(v[1], p->rp_id) < 0 ||
+	    unpack_blob(v[2], &p->cdh) < 0 ||
+	    unpack_blob(v[3], &p->attobj) < 0 ||
+	    unpack_byte(v[4], &p->type) < 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[5], *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_int(p->seed)) == NULL ||
+	    (argv[1] = pack_string(p->rp_id)) == NULL ||
+	    (argv[2] = pack_blob(&p->cdh)) == NULL ||
+	    (argv[3] = pack_blob(&p->attobj)) == NULL ||
+	    (argv[4] = pack_byte(p->type)) == NULL)
+		goto fail;
+
+	for (size_t i = 0; i < 5; i++)
+		if (cbor_array_push(array, argv[i]) == false)
+			goto fail;
+
+	if ((cbor_len = cbor_serialize_alloc(array, &cbor,
+	    &cbor_alloc_len)) == 0 || cbor_len > len) {
+		cbor_len = 0;
+		goto fail;
+	}
+
+	memcpy(ptr, cbor, cbor_len);
+fail:
+	for (size_t i = 0; i < 5; 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;
+
+	dummy.type = 1;
+
+	strlcpy(dummy.rp_id, dummy_rp_id, sizeof(dummy.rp_id));
+
+	dummy.cdh.len = sizeof(dummy_cdh);
+	dummy.attobj.len = sizeof(dummy_attestation_object);
+
+	memcpy(&dummy.cdh.body, &dummy_cdh, dummy.cdh.len);
+	memcpy(&dummy.attobj.body, dummy_attestation_object, dummy.attobj.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;
+}
+
+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->type);
+		p->attobj.len = sizeof(dummy_attestation_object);
+		memcpy(&p->attobj.body, &dummy_attestation_object,
+		    p->attobj.len);
+		mutate_blob(&p->attobj);
+	}
+}
+
+void
+test(const struct param *p)
+{
+	fido_cred_t *cred = NULL;
+	int r, cose_alg;
+
+	prng_init((unsigned int)p->seed);
+	fuzz_clock_reset();
+	fido_init(FIDO_DEBUG);
+	fido_set_log_handler(consume_str);
+
+	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;
+	}
+
+	r = fido_cred_set_type(cred, cose_alg);
+	consume(&r, sizeof(r));
+	r = fido_cred_set_rp(cred, p->rp_id, NULL);
+	consume(&r, sizeof(r));
+	r = fido_cred_set_clientdata_hash(cred, p->cdh.body, p->cdh.len);
+	consume(&r, sizeof(r));
+	r = fido_cred_set_attobj(cred, p->attobj.body, p->attobj.len);
+	consume(&r, sizeof(r));
+
+	consume_str(fido_cred_fmt(cred));
+	consume(fido_cred_attstmt_ptr(cred), fido_cred_attstmt_len(cred));
+	consume(fido_cred_authdata_ptr(cred), fido_cred_authdata_len(cred));
+	r = fido_cred_verify(cred);
+	consume(&r, sizeof(r));
+
+	fido_cred_free(&cred);
+}