1 /*
2 * Copyright (C) 2024 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "host/commands/process_sandboxer/policies.h"
18
19 #include <sys/mman.h>
20 #include <sys/socket.h>
21 #include <syscall.h>
22
23 #include <sandboxed_api/sandbox2/policybuilder.h>
24 #include <sandboxed_api/sandbox2/util/bpf_helper.h>
25
26 #include "host/commands/process_sandboxer/filesystem.h"
27
28 namespace cuttlefish::process_sandboxer {
29
WmediumdPolicy(const HostInfo & host)30 sandbox2::PolicyBuilder WmediumdPolicy(const HostInfo& host) {
31 return BaselinePolicy(host, host.HostToolExe("wmediumd"))
32 .AddDirectory(host.environments_uds_dir, /* is_ro= */ false)
33 .AddDirectory(host.instance_uds_dir, /* is_ro= */ false)
34 .AddDirectory(host.log_dir, /* is_ro= */ false)
35 .AddFile("/dev/urandom") // For gRPC
36 .AddFile(JoinPath(host.environments_dir, "env-1", "wmediumd.cfg"),
37 /* is_ro= */ false)
38 .AddFile(host.cuttlefish_config_path)
39 // Shared memory with crosvm for wifi
40 .AddPolicyOnMmap([](bpf_labels& labels) -> std::vector<sock_filter> {
41 return {
42 ARG_32(2), // prot
43 JNE32(PROT_READ | PROT_WRITE, JUMP(&labels, cf_webrtc_mmap_end)),
44 ARG_32(3), // flags
45 JEQ32(MAP_SHARED, ALLOW),
46 LABEL(&labels, cf_webrtc_mmap_end),
47 };
48 })
49 .AddPolicyOnSyscalls(
50 {__NR_getsockopt, __NR_setsockopt},
51 [](bpf_labels& labels) -> std::vector<sock_filter> {
52 return {
53 ARG_32(1), // level
54 JNE32(SOL_SOCKET,
55 JUMP(&labels, cf_screen_recording_server_getsockopt_end)),
56 ARG_32(2), // optname
57 JEQ32(SO_REUSEPORT, ALLOW),
58 LABEL(&labels, cf_screen_recording_server_getsockopt_end),
59 };
60 })
61 .AddPolicyOnSyscall(__NR_madvise,
62 {ARG_32(2), JEQ32(MADV_DONTNEED, ALLOW)})
63 // Unclear what's creating the INET and INET6 sockets
64 .AddPolicyOnSyscall(__NR_socket, {ARG_32(0), JEQ32(AF_UNIX, ALLOW),
65 JEQ32(AF_INET, ERRNO(EACCES)),
66 JEQ32(AF_INET6, ERRNO(EACCES))})
67 .AllowEventFd()
68 .AllowHandleSignals()
69 .AllowSafeFcntl()
70 .AllowSelect()
71 .AllowSleep()
72 .AllowSyscall(__NR_accept)
73 .AllowSyscall(__NR_bind)
74 .AllowSyscall(__NR_clone) // Multithreading
75 .AllowSyscall(__NR_getpeername)
76 .AllowSyscall(__NR_getsockname)
77 .AllowSyscall(__NR_listen)
78 .AllowSyscall(__NR_msgget)
79 .AllowSyscall(__NR_msgsnd)
80 .AllowSyscall(__NR_msgrcv)
81 .AllowSyscall(__NR_recvmsg)
82 .AllowSyscall(__NR_sched_getparam)
83 .AllowSyscall(__NR_sched_getscheduler)
84 .AllowSyscall(__NR_sched_yield)
85 .AllowSyscall(__NR_sendmsg)
86 .AllowSyscall(__NR_shutdown)
87 .AllowSyscall(__NR_timerfd_create)
88 .AllowSyscall(__NR_timerfd_settime);
89 }
90
91 } // namespace cuttlefish::process_sandboxer
92