1 files changed, 143 insertions, 0 deletions
diff --git a/fuzzers/packfile_fuzzer.c b/fuzzers/packfile_fuzzer.c
new file mode 100644
index 0000000..aeba957
--- /dev/null
+++ b/fuzzers/packfile_fuzzer.c
@@ -0,0 +1,143 @@
+/*
+ * libgit2 packfile fuzzer target.
+ *
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include <stdio.h>
+
+#include "git2.h"
+#include "git2/sys/mempack.h"
+#include "common.h"
+#include "str.h"
+
+#include "standalone_driver.h"
+
+static git_odb *odb = NULL;
+static git_odb_backend *mempack = NULL;
+
+/* Arbitrary object to seed the ODB. */
+static const unsigned char base_obj[] = { 07, 076 };
+static const unsigned int base_obj_len = 2;
+
+int LLVMFuzzerInitialize(int *argc, char ***argv)
+{
+	GIT_UNUSED(argc);
+	GIT_UNUSED(argv);
+
+	if (git_libgit2_init() < 0) {
+		fprintf(stderr, "Failed to initialize libgit2\n");
+		abort();
+	}
+	if (git_libgit2_opts(GIT_OPT_SET_PACK_MAX_OBJECTS, 10000000) < 0) {
+		fprintf(stderr, "Failed to limit maximum pack object count\n");
+		abort();
+	}
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+	if (git_odb_new(&odb, NULL) < 0) {
+		fprintf(stderr, "Failed to create the odb\n");
+		abort();
+	}
+#else
+	if (git_odb_new(&odb) < 0) {
+		fprintf(stderr, "Failed to create the odb\n");
+		abort();
+	}
+#endif
+
+	if (git_mempack_new(&mempack) < 0) {
+		fprintf(stderr, "Failed to create the mempack\n");
+		abort();
+	}
+	if (git_odb_add_backend(odb, mempack, 999) < 0) {
+		fprintf(stderr, "Failed to add the mempack\n");
+		abort();
+	}
+	return 0;
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+{
+	git_indexer_progress stats = {0, 0};
+	git_indexer *indexer = NULL;
+	git_str path = GIT_STR_INIT;
+	git_oid oid;
+	bool append_hash = false;
+	int error;
+
+	if (size == 0)
+		return 0;
+
+	if (!odb || !mempack) {
+		fprintf(stderr, "Global state not initialized\n");
+		abort();
+	}
+	git_mempack_reset(mempack);
+
+	if (git_odb_write(&oid, odb, base_obj, base_obj_len, GIT_OBJECT_BLOB) < 0) {
+		fprintf(stderr, "Failed to add an object to the odb\n");
+		abort();
+	}
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+	error = git_indexer_new(&indexer, ".", GIT_OID_SHA1, NULL);
+#else
+	error = git_indexer_new(&indexer, ".", 0, odb, NULL);
+#endif
+
+	if (error < 0) {
+		fprintf(stderr, "Failed to create the indexer: %s\n",
+			git_error_last()->message);
+		abort();
+	}
+
+	/*
+	 * If the first byte in the stream has the high bit set, append the
+	 * SHA1 hash so that the packfile is somewhat valid.
+	 */
+	append_hash = *data & 0x80;
+	++data;
+	--size;
+
+	if (git_indexer_append(indexer, data, size, &stats) < 0)
+		goto cleanup;
+	if (append_hash) {
+#ifdef GIT_EXPERIMENTAL_SHA256
+		if (git_odb_hash(&oid, data, size, GIT_OBJECT_BLOB, GIT_OID_SHA1) < 0) {
+			fprintf(stderr, "Failed to compute the SHA1 hash\n");
+			abort();
+		}
+#else
+		if (git_odb_hash(&oid, data, size, GIT_OBJECT_BLOB) < 0) {
+			fprintf(stderr, "Failed to compute the SHA1 hash\n");
+			abort();
+		}
+#endif
+
+		if (git_indexer_append(indexer, &oid.id, GIT_OID_SHA1_SIZE, &stats) < 0) {
+			goto cleanup;
+		}
+	}
+	if (git_indexer_commit(indexer, &stats) < 0)
+		goto cleanup;
+
+	if (git_str_printf(&path, "pack-%s.idx", git_indexer_name(indexer)) < 0)
+		goto cleanup;
+	p_unlink(git_str_cstr(&path));
+
+	git_str_clear(&path);
+
+	if (git_str_printf(&path, "pack-%s.pack", git_indexer_name(indexer)) < 0)
+		goto cleanup;
+	p_unlink(git_str_cstr(&path));
+
+cleanup:
+	git_mempack_reset(mempack);
+	git_indexer_free(indexer);
+	git_str_dispose(&path);
+	return 0;
+}