Add fuzz targets, custom mutator and fuzzing dictionary

tests/fuzz/crypt2_load_fuzz.cc

@@ -0,0 +1,155 @@
+/*
+ * cryptsetup LUKS2 fuzz target
+ *
+ * Copyright (C) 2022 Daniel Zatovic <daniel.zatovic@gmail.com>
+ * Copyright (C) 2022 Red Hat, Inc. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+extern "C" {
+#define FILESIZE (16777216)
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/mman.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <inttypes.h>
+#include <sys/types.h>
+#include <err.h>
+
+#include "crypto_backend/crypto_backend.h"
+#include <luks2/luks2.h>
+#include <libcryptsetup.h>
+#include <src/cryptsetup.h>
+
+#include "common.h"
+
+int calculate_checksum(const uint8_t* data, size_t size) {
+	struct crypt_hash *hd = NULL;
+	struct luks2_hdr_disk *hdr = NULL;
+	int hash_size;
+	uint64_t hdr_size1, hdr_size2;
+	int r = 0;
+
+	// primary header
+	if (sizeof(struct luks2_hdr_disk) > size)
+		return 0;
+	hdr = (struct luks2_hdr_disk *) data;
+
+	hdr_size1 = be64_to_cpu(hdr->hdr_size);
+	if (hdr_size1 > size)
+		return 0;
+	memset(&hdr->csum, 0, LUKS2_CHECKSUM_L);
+	if ((r = crypt_hash_init(&hd, "sha256")))
+		goto out;
+	if ((r = crypt_hash_write(hd, (char*) data, hdr_size1)))
+		goto out;
+	hash_size = crypt_hash_size("sha256");
+	if (hash_size <= 0) {
+		r = 1;
+		goto out;
+	}
+	if ((r = crypt_hash_final(hd, (char*)&hdr->csum, (size_t)hash_size)))
+		goto out;
+	crypt_hash_destroy(hd);
+
+	// secondary header
+	if (hdr_size1 < sizeof(struct luks2_hdr_disk))
+		hdr_size1 = sizeof(struct luks2_hdr_disk);
+
+	if (hdr_size1 + sizeof(struct luks2_hdr_disk) > size)
+		return 0;
+	hdr = (struct luks2_hdr_disk *) (data + hdr_size1);
+
+	hdr_size2 = be64_to_cpu(hdr->hdr_size);
+	if (hdr_size1 + hdr_size2 > size)
+		return 0;
+
+	memset(&hdr->csum, 0, LUKS2_CHECKSUM_L);
+	if ((r = crypt_hash_init(&hd, "sha256")))
+		goto out;
+	if ((r = crypt_hash_write(hd, (char*) hdr, hdr_size2)))
+		goto out;
+	if ((r = crypt_hash_final(hd, (char*)&hdr->csum, (size_t)hash_size)))
+		goto out;
+
+out:
+	if (hd)
+		crypt_hash_destroy(hd);
+	return r;
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+	int fd;
+	struct crypt_device *cd;
+	int result;
+	uint8_t *map;
+	int r = 0;
+
+	char name[] = "/tmp/test-script-fuzz.XXXXXX";
+
+	if ((r = calculate_checksum(data, size)))
+		return r;
+
+	fd = mkostemp(name, O_RDWR|O_CREAT|O_EXCL|O_CLOEXEC);
+	if (fd < 0)
+		err(EXIT_FAILURE, "mkostemp() failed");
+
+	result = lseek(fd, FILESIZE-1, SEEK_SET);
+	if (result == -1) {
+		r = 1;
+		goto out;
+	}
+	result = write(fd, "\0", 1);
+	if (result != 1) {
+		r = 1;
+		goto out;
+	}
+	result = lseek(fd, 0, SEEK_SET);
+	if (result == -1) {
+		r = 1;
+		goto out;
+	}
+
+	if (write_all(fd, data, size) != 0) {
+		r = 1;
+		goto out;
+	}
+
+//	crypt_set_debug_level(CRYPT_DEBUG_ALL);
+
+	r = crypt_init(&cd, name);
+	if (r < 0 ) {
+		r = 0;
+		goto out;
+	}
+
+	r = crypt_load(cd, CRYPT_LUKS2, NULL);
+	crypt_free(cd);
+	if (r < 0) {
+		r = 0;
+		goto out;
+	}
+
+out:
+	close(fd);
+	unlink(name);
+	return r;
+}
+}