1 // This file is an example of a network sandboxed binary inside a network
2 // namespace. It can't connect with the server directly, but the executor can
3 // establish a connection and pass the connected socket to the sandboxee.
4
5 #include <arpa/inet.h>
6 #include <netinet/in.h>
7 #include <sys/socket.h>
8 #include <sys/types.h>
9 #include <unistd.h>
10
11 #include <cerrno>
12 #include <cstdint>
13 #include <cstring>
14
15 #include "absl/base/log_severity.h"
16 #include "absl/flags/flag.h"
17 #include "absl/flags/parse.h"
18 #include "absl/log/globals.h"
19 #include "absl/log/initialize.h"
20 #include "absl/log/log.h"
21 #include "absl/status/status.h"
22 #include "absl/status/statusor.h"
23 #include "absl/strings/str_format.h"
24 #include "absl/strings/string_view.h"
25 #include "sandboxed_api/sandbox2/client.h"
26 #include "sandboxed_api/sandbox2/comms.h"
27 #include "sandboxed_api/sandbox2/network_proxy/client.h"
28 #include "sandboxed_api/util/fileops.h"
29 #include "sandboxed_api/util/status_macros.h"
30
31 ABSL_FLAG(bool, connect_with_handler, true, "Connect using automatic mode.");
32
33 namespace {
34
35 static sandbox2::NetworkProxyClient* g_proxy_client;
36
ReadFromFd(int fd,uint8_t * buf,size_t size)37 ssize_t ReadFromFd(int fd, uint8_t* buf, size_t size) {
38 ssize_t received = 0;
39 while (received < size) {
40 ssize_t read_status =
41 TEMP_FAILURE_RETRY(read(fd, &buf[received], size - received));
42 if (read_status == 0) {
43 break;
44 }
45 if (read_status < 0) {
46 return -1;
47 }
48 received += read_status;
49 }
50 return received;
51 }
52
CommunicationTest(int sock)53 absl::Status CommunicationTest(int sock) {
54 char received[1025] = {0};
55
56 if (ReadFromFd(sock, reinterpret_cast<uint8_t*>(received),
57 sizeof(received) - 1) <= 0) {
58 return absl::InternalError("Data receiving error");
59 }
60 absl::PrintF("Sandboxee received data from the server:\n\n%s\n", received);
61 if (strcmp(received, "Hello World\n")) {
62 return absl::InternalError("Data receiving error");
63 }
64 return absl::OkStatus();
65 }
66
CreateAddres(int port)67 absl::StatusOr<struct sockaddr_in6> CreateAddres(int port) {
68 static struct sockaddr_in6 saddr {};
69 saddr.sin6_family = AF_INET6;
70 saddr.sin6_port = htons(port);
71
72 if (int err = inet_pton(AF_INET6, "::1", &saddr.sin6_addr); err <= 0) {
73 return absl::ErrnoToStatus(errno, "socket()");
74 }
75 return saddr;
76 }
77
ConnectManually(int s,const struct sockaddr_in6 & saddr)78 absl::Status ConnectManually(int s, const struct sockaddr_in6& saddr) {
79 return g_proxy_client->Connect(
80 s, reinterpret_cast<const struct sockaddr*>(&saddr), sizeof(saddr));
81 }
82
ConnectWithHandler(int s,const struct sockaddr_in6 & saddr)83 absl::Status ConnectWithHandler(int s, const struct sockaddr_in6& saddr) {
84 int err = connect(s, reinterpret_cast<const struct sockaddr*>(&saddr),
85 sizeof(saddr));
86 if (err != 0) {
87 return absl::InternalError("connect() failed");
88 }
89
90 return absl::OkStatus();
91 }
92
ConnectToServer(int port)93 absl::StatusOr<int> ConnectToServer(int port) {
94 SAPI_ASSIGN_OR_RETURN(struct sockaddr_in6 saddr, CreateAddres(port));
95
96 sapi::file_util::fileops::FDCloser s(socket(AF_INET6, SOCK_STREAM, 0));
97 if (s.get() < 0) {
98 return absl::ErrnoToStatus(errno, "socket()");
99 }
100
101 if (absl::GetFlag(FLAGS_connect_with_handler)) {
102 SAPI_RETURN_IF_ERROR(ConnectWithHandler(s.get(), saddr));
103 } else {
104 SAPI_RETURN_IF_ERROR(ConnectManually(s.get(), saddr));
105 }
106
107 LOG(INFO) << "Connected to the server";
108 return s.Release();
109 }
110
111 } // namespace
112
main(int argc,char * argv[])113 int main(int argc, char* argv[]) {
114 absl::SetStderrThreshold(absl::LogSeverityAtLeast::kInfo);
115 absl::ParseCommandLine(argc, argv);
116 absl::InitializeLog();
117
118 // Set-up the sandbox2::Client object, using a file descriptor (1023).
119 sandbox2::Comms comms(sandbox2::Comms::kDefaultConnection);
120 sandbox2::Client sandbox2_client(&comms);
121
122 // Enable sandboxing from here.
123 sandbox2_client.SandboxMeHere();
124
125 if (absl::GetFlag(FLAGS_connect_with_handler)) {
126 if (auto status = sandbox2_client.InstallNetworkProxyHandler();
127 !status.ok()) {
128 LOG(ERROR) << "InstallNetworkProxyHandler() failed: " << status.message();
129 return 1;
130 }
131 } else {
132 g_proxy_client = sandbox2_client.GetNetworkProxyClient();
133 }
134
135 // Receive port number of the server
136 int port;
137 if (!comms.RecvInt32(&port)) {
138 LOG(ERROR) << "Failed to receive port number";
139 return 2;
140 }
141
142 absl::StatusOr<int> sock_s = ConnectToServer(port);
143 if (!sock_s.ok()) {
144 LOG(ERROR) << sock_s.status().message();
145 return 3;
146 }
147 sapi::file_util::fileops::FDCloser client(sock_s.value());
148
149 if (auto status = CommunicationTest(client.get()); !status.ok()) {
150 LOG(ERROR) << status.message();
151 return 4;
152 }
153 return 0;
154 }
155