trusty: Add simple fuzzer for keymaster TA

Adds a simple libfuzzer-based coverage guided fuzzer for keymaster.
Current coverage is low, so we'll need to improve this with an initial
corpus or a more sophisticated protocol aware fuzzer.

Bug: 175918322
Test: make trusty_keymaster_fuzzer
Test: adb shell /data/fuzz/arm64/trusty_keymaster_fuzzer/trusty_keymaster_fuzzer
Change-Id: Iad1713e1a73cc5a6a3ec742cc433d1337aca9bc3

trusty/keymaster/fuzz/Android.bp

@@ -0,0 +1,19 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//       http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+cc_fuzz {
+    name: "trusty_keymaster_fuzzer",
+    defaults: ["trusty_fuzzer_defaults"],
+    srcs: ["fuzz.cpp"],
+}

trusty/keymaster/fuzz/fuzz.cpp

@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#undef NDEBUG
+
+#include <assert.h>
+#include <log/log.h>
+#include <stdlib.h>
+#include <trusty/coverage/coverage.h>
+#include <trusty/fuzz/counters.h>
+#include <trusty/fuzz/utils.h>
+#include <unistd.h>
+#include <iostream>
+
+using android::trusty::coverage::CoverageRecord;
+using android::trusty::fuzz::ExtraCounters;
+using android::trusty::fuzz::TrustyApp;
+
+#define TIPC_DEV "/dev/trusty-ipc-dev0"
+#define KEYMASTER_PORT "com.android.trusty.keymaster"
+#define KEYMASTER_MODULE_FILENAME "keymaster.syms.elf"
+
+/* Keymaster TA's UUID is 5f902ace-5e5c-4cd8-ae54-87b88c22ddaf */
+static struct uuid keymaster_uuid = {
+        0x5f902ace,
+        0x5e5c,
+        0x4cd8,
+        {0xae, 0x54, 0x87, 0xb8, 0x8c, 0x22, 0xdd, 0xaf},
+};
+
+static CoverageRecord record(TIPC_DEV, &keymaster_uuid, KEYMASTER_MODULE_FILENAME);
+
+extern "C" int LLVMFuzzerInitialize(int* /* argc */, char*** /* argv */) {
+    auto ret = record.Open();
+    if (!ret.ok()) {
+        std::cerr << ret.error() << std::endl;
+        exit(-1);
+    }
+    return 0;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+    static uint8_t buf[TIPC_MAX_MSG_SIZE];
+
+    ExtraCounters counters(&record);
+    counters.Reset();
+
+    android::trusty::fuzz::TrustyApp ta(TIPC_DEV, KEYMASTER_PORT);
+    auto ret = ta.Connect();
+    if (!ret.ok()) {
+        android::trusty::fuzz::Abort();
+    }
+
+    /* Send message to test server */
+    ret = ta.Write(data, size);
+    if (!ret.ok()) {
+        return -1;
+    }
+
+    /* Read message from test server */
+    ret = ta.Read(&buf, sizeof(buf));
+    if (!ret.ok()) {
+        return -1;
+    }
+
+    return 0;
+}