sandboxed-api/sandboxed_api/sandbox2/network_proxy/client.cc

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// Copyright 2019 Google LLC
//
// 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
//
// https://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 "sandboxed_api/sandbox2/network_proxy/client.h"
#include <sys/socket.h>
#include <syscall.h>
#include <unistd.h>
#include <cerrno>
#include <cstdint>
#include "absl/log/log.h"
#include "absl/status/status.h"
#include "absl/synchronization/mutex.h"
#include "sandboxed_api/sandbox2/util/syscall_trap.h"
#include "sandboxed_api/util/status_macros.h"
namespace sandbox2 {
absl::Status NetworkProxyClient::Connect(int sockfd,
const struct sockaddr* addr,
socklen_t addrlen) {
absl::MutexLock lock(&mutex_);
// Check if socket is SOCK_STREAM
int type;
socklen_t type_size = sizeof(int);
int result = getsockopt(sockfd, SOL_SOCKET, SO_TYPE, &type, &type_size);
if (result == -1) {
return absl::FailedPreconditionError("Invalid socket FD");
}
if (type_size != sizeof(int) || type != SOCK_STREAM) {
errno = EINVAL;
return absl::InvalidArgumentError(
"Invalid socket, only SOCK_STREAM is allowed");
}
// Send sockaddr struct
if (!comms_.SendBytes(reinterpret_cast<const uint8_t*>(addr), addrlen)) {
errno = EIO;
return absl::InternalError("Sending data to network proxy failed");
}
SAPI_RETURN_IF_ERROR(ReceiveRemoteResult());
// Receive new socket
int s;
if (!comms_.RecvFD(&s)) {
errno = EIO;
return absl::InternalError("Receiving data from network proxy failed");
}
if (dup2(s, sockfd) == -1) {
close(s);
return absl::InternalError("Processing data from network proxy failed");
}
return absl::OkStatus();
}
absl::Status NetworkProxyClient::ReceiveRemoteResult() {
int result;
if (!comms_.RecvInt32(&result)) {
errno = EIO;
return absl::InternalError("Receiving data from the network proxy failed");
}
if (result != 0) {
errno = result;
return absl::ErrnoToStatus(errno, "Error in network proxy server");
}
return absl::OkStatus();
}
NetworkProxyClient* NetworkProxyHandler::network_proxy_client_ = nullptr;
absl::Status NetworkProxyHandler::InstallNetworkProxyHandler(
NetworkProxyClient* npc) {
if (network_proxy_client_ != nullptr) {
return absl::AlreadyExistsError(
"Network proxy handler is already installed");
}
network_proxy_client_ = npc;
if (!SyscallTrap::Install([](int nr, SyscallTrap::Args args, uintptr_t* rv) {
return ProcessSeccompTrap(nr, args, rv);
})) {
return absl::InternalError("Could not install syscall trap");
}
return absl::OkStatus();
}
bool NetworkProxyHandler::ProcessSeccompTrap(int nr, SyscallTrap::Args args,
uintptr_t* rv) {
int sockfd;
const struct sockaddr* addr;
socklen_t addrlen;
if (nr == __NR_connect) {
sockfd = static_cast<int>(args[0]);
addr = reinterpret_cast<const struct sockaddr*>(args[1]);
addrlen = static_cast<socklen_t>(args[2]);
#if defined(SAPI_PPC64_LE)
} else if (nr == __NR_socketcall &&
static_cast<int>(args[0]) == SYS_CONNECT) {
auto* connect_args = reinterpret_cast<uint64_t*>(args[1]);
sockfd = static_cast<int>(connect_args[0]);
addr = reinterpret_cast<const struct sockaddr*>(connect_args[1]);
addrlen = static_cast<socklen_t>(connect_args[2]);
#endif
} else {
return false;
}
absl::Status result = network_proxy_client_->Connect(sockfd, addr, addrlen);
if (result.ok()) {
*rv = 0;
} else {
*rv = -errno;
}
return true;
}
} // namespace sandbox2