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/*
* Copyright (C) 2021 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.
*/
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/unique_fd.h>
#include <binder/Binder.h>
#include <binder/Parcel.h>
#include <binder/RpcServer.h>
#include <binder/RpcTlsTestUtils.h>
#include <binder/RpcTransport.h>
#include <binder/RpcTransportRaw.h>
#include <binder/RpcTransportTls.h>
#include <fuzzer/FuzzedDataProvider.h>
#include <openssl/rand.h>
#include <openssl/ssl.h>
#include <sys/resource.h>
#include <sys/un.h>
namespace android {
static const std::string kSock = std::string(getenv("TMPDIR") ?: "/tmp") +
"/binderRpcFuzzerSocket_" + std::to_string(getpid());
class SomeBinder : public BBinder {
status_t onTransact(uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags = 0) {
(void)flags;
if ((code & 1) == 0) {
sp<IBinder> binder;
(void)data.readStrongBinder(&binder);
if (binder != nullptr) {
(void)binder->pingBinder();
}
}
if ((code & 2) == 0) {
(void)data.readInt32();
}
if ((code & 4) == 0) {
(void)reply->writeStrongBinder(sp<BBinder>::make());
}
return OK;
}
};
int passwordCallback(char* buf, int size, int /*rwflag*/, void* /*u*/) {
constexpr const char pass[] = "xxxx"; // See create_certs.sh
if (size <= 0) return 0;
int numCopy = std::min<int>(size, sizeof(pass));
(void)memcpy(buf, pass, numCopy);
return numCopy;
}
struct ServerAuth {
bssl::UniquePtr<EVP_PKEY> pkey;
bssl::UniquePtr<X509> cert;
};
// Use pre-configured keys because runtime generated keys / certificates are not
// deterministic, and the algorithm is time consuming.
ServerAuth readServerKeyAndCert() {
ServerAuth ret;
auto keyPath = android::base::GetExecutableDirectory() + "/data/server.key";
bssl::UniquePtr<BIO> keyBio(BIO_new_file(keyPath.c_str(), "r"));
ret.pkey.reset(PEM_read_bio_PrivateKey(keyBio.get(), nullptr, passwordCallback, nullptr));
CHECK_NE(ret.pkey.get(), nullptr);
auto certPath = android::base::GetExecutableDirectory() + "/data/server.crt";
bssl::UniquePtr<BIO> certBio(BIO_new_file(certPath.c_str(), "r"));
ret.cert.reset(PEM_read_bio_X509(certBio.get(), nullptr, nullptr, nullptr));
CHECK_NE(ret.cert.get(), nullptr);
return ret;
}
std::unique_ptr<RpcAuth> createServerRpcAuth() {
static auto sAuth = readServerKeyAndCert();
CHECK(EVP_PKEY_up_ref(sAuth.pkey.get()));
bssl::UniquePtr<EVP_PKEY> pkey(sAuth.pkey.get());
CHECK(X509_up_ref(sAuth.cert.get()));
bssl::UniquePtr<X509> cert(sAuth.cert.get());
return std::make_unique<RpcAuthPreSigned>(std::move(pkey), std::move(cert));
}
std::unique_ptr<RpcTransportCtxFactory> makeTransportCtxFactory(FuzzedDataProvider* provider) {
bool isTls = provider->ConsumeBool();
if (!isTls) {
return RpcTransportCtxFactoryRaw::make();
}
status_t verifyStatus = provider->ConsumeIntegral<status_t>();
auto verifier = std::make_shared<RpcCertificateVerifierNoOp>(verifyStatus);
return RpcTransportCtxFactoryTls::make(verifier, createServerRpcAuth());
}
extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
if (size > 50000) return 0;
FuzzedDataProvider provider(data, size);
RAND_reset_for_fuzzing();
unlink(kSock.c_str());
sp<RpcServer> server = RpcServer::make(makeTransportCtxFactory(&provider));
server->setRootObject(sp<SomeBinder>::make());
CHECK_EQ(OK, server->setupUnixDomainServer(kSock.c_str()));
std::thread serverThread([=] { (void)server->join(); });
sockaddr_un addr{
.sun_family = AF_UNIX,
};
CHECK_LT(kSock.size(), sizeof(addr.sun_path));
memcpy(&addr.sun_path, kSock.c_str(), kSock.size());
std::vector<base::unique_fd> connections;
bool hangupBeforeShutdown = provider.ConsumeBool();
// b/260736889 - limit arbitrarily, due to thread resource exhaustion, which currently
// aborts. Servers should consider RpcServer::setConnectionFilter instead.
constexpr size_t kMaxConnections = 10;
while (provider.remaining_bytes() > 0) {
if (connections.empty() ||
(connections.size() < kMaxConnections && provider.ConsumeBool())) {
base::unique_fd fd(TEMP_FAILURE_RETRY(socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0)));
CHECK_NE(fd.get(), -1);
CHECK_EQ(0,
TEMP_FAILURE_RETRY(
connect(fd.get(), reinterpret_cast<sockaddr*>(&addr), sizeof(addr))))
<< strerror(errno);
connections.push_back(std::move(fd));
} else {
size_t idx = provider.ConsumeIntegralInRange<size_t>(0, connections.size() - 1);
if (provider.ConsumeBool()) {
std::string writeData = provider.ConsumeRandomLengthString();
ssize_t size = TEMP_FAILURE_RETRY(send(connections.at(idx).get(), writeData.data(),
writeData.size(), MSG_NOSIGNAL));
CHECK(errno == EPIPE || size == writeData.size())
<< size << " " << writeData.size() << " " << strerror(errno);
} else {
connections.erase(connections.begin() + idx); // hang up
}
}
}
if (hangupBeforeShutdown) {
connections.clear();
while (!server->listSessions().empty() || server->numUninitializedSessions()) {
// wait for all threads to finish processing existing information
usleep(1);
}
}
while (server->hasActiveRequests()) {
usleep(10);
}
while (!server->shutdown()) usleep(1);
serverThread.join();
return 0;
}
} // namespace android
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