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 <linux/filter.h>
20 #include <linux/prctl.h>
21 #include <linux/sockios.h>
22 #include <netinet/in.h>
23 #include <netinet/tcp.h>
24 #include <sys/ioctl.h>
25 #include <sys/mman.h>
26 #include <sys/socket.h>
27 #include <syscall.h>
28
29 #include <vector>
30
31 #include <sandboxed_api/sandbox2/allowlists/unrestricted_networking.h>
32 #include <sandboxed_api/sandbox2/policybuilder.h>
33 #include <sandboxed_api/sandbox2/util/bpf_helper.h>
34 #include <sandboxed_api/util/path.h>
35
36 namespace cuttlefish::process_sandboxer {
37
38 using sapi::file::JoinPath;
39
WebRtcPolicy(const HostInfo & host)40 sandbox2::PolicyBuilder WebRtcPolicy(const HostInfo& host) {
41 return BaselinePolicy(host, host.HostToolExe("webRTC"))
42 .AddDirectory(host.log_dir, /* is_ro= */ false)
43 .AddDirectory(
44 JoinPath(host.host_artifacts_path, "/usr/share/webrtc/assets"))
45 .AddDirectory(host.InstanceUdsDir(), /* is_ro= */ false)
46 .AddDirectory(host.VsockDeviceDir(), /* is_ro= */ false)
47 .AddDirectory(JoinPath(host.runtime_dir, "recording"), /* is_ro= */ false)
48 .AddFile(host.cuttlefish_config_path)
49 .AddFile("/dev/urandom")
50 .AddFile("/run/cuttlefish/operator")
51 // Shared memory with crosvm for audio
52 .AddPolicyOnMmap([](bpf_labels& labels) -> std::vector<sock_filter> {
53 return {
54 ARG_32(2), // prot
55 JNE32(PROT_READ | PROT_WRITE, JUMP(&labels, cf_webrtc_mmap_end)),
56 ARG_32(3), // flags
57 JEQ32(MAP_SHARED, ALLOW),
58 LABEL(&labels, cf_webrtc_mmap_end),
59 };
60 })
61 .AddPolicyOnSyscall(
62 __NR_getsockopt,
63 [](bpf_labels& labels) -> std::vector<sock_filter> {
64 return {
65 ARG_32(1), // level
66 JNE32(SOL_SOCKET, JUMP(&labels, cf_webrtc_getsockopt_end)),
67 ARG_32(2), // optname
68 JEQ32(SO_ERROR, ALLOW),
69 JEQ32(SO_PEERCRED, ALLOW),
70 LABEL(&labels, cf_webrtc_getsockopt_end),
71 };
72 })
73 .AddPolicyOnSyscall(__NR_ioctl, {ARG_32(1), JEQ32(SIOCGSTAMP, ALLOW),
74 JEQ32(FIONREAD, ALLOW)})
75 .AddPolicyOnSyscall(__NR_madvise,
76 {ARG_32(2), JEQ32(MADV_WIPEONFORK, ALLOW),
77 JEQ32(MADV_DONTNEED, ALLOW),
78 // TODO: schuffelen - find out what this is
79 JEQ32(0xffffffff, ALLOW)})
80 .AddPolicyOnSyscall(__NR_prctl,
81 {ARG_32(0), JEQ32(PR_CAPBSET_READ, ALLOW)})
82 .AddPolicyOnSyscall(
83 __NR_setsockopt,
84 [](bpf_labels& labels) -> std::vector<sock_filter> {
85 return {
86 ARG_32(1), // level
87 JEQ32(SOL_IP, JUMP(&labels, cf_webrtc_setsockopt_ip)),
88 JEQ32(SOL_IPV6, JUMP(&labels, cf_webrtc_setsockopt_ipv6)),
89 JEQ32(SOL_SOCKET, JUMP(&labels, cf_webrtc_setsockopt_sol)),
90 JNE32(IPPROTO_TCP, JUMP(&labels, cf_webrtc_setsockopt_end)),
91 // IPPROTO_TCP
92 ARG_32(2), // optname
93 JEQ32(TCP_NODELAY, ALLOW),
94 JUMP(&labels, cf_webrtc_setsockopt_end),
95 // SOL_IP
96 LABEL(&labels, cf_webrtc_setsockopt_ip),
97 ARG_32(2), // optname
98 JEQ32(IP_RECVERR, ALLOW),
99 JEQ32(IP_TOS, ALLOW),
100 JEQ32(IP_RETOPTS, ALLOW),
101 JEQ32(IP_PKTINFO, ALLOW),
102 JUMP(&labels, cf_webrtc_setsockopt_end),
103 // SOL_IPV6
104 LABEL(&labels, cf_webrtc_setsockopt_ipv6),
105 ARG_32(2), // optname
106 JEQ32(IPV6_TCLASS, ALLOW),
107 JUMP(&labels, cf_webrtc_setsockopt_end),
108 // SOL_SOCKET
109 LABEL(&labels, cf_webrtc_setsockopt_sol),
110 ARG_32(2), // optname
111 JEQ32(SO_REUSEADDR, ALLOW),
112 JEQ32(SO_SNDBUF, ALLOW),
113 JEQ32(SO_RCVBUF, ALLOW),
114 LABEL(&labels, cf_webrtc_setsockopt_end),
115 };
116 })
117 .AddPolicyOnSyscall(
118 __NR_socket, {ARG_32(0), JEQ32(AF_INET, ALLOW), JEQ32(AF_UNIX, ALLOW),
119 JEQ32(AF_INET6, ALLOW),
120 // webrtc/rtc_base/ifaddrs_android.cc
121 JEQ32(AF_NETLINK, ALLOW), JEQ32(AF_VSOCK, ALLOW)})
122 .Allow(sandbox2::UnrestrictedNetworking())
123 .AllowEpoll()
124 .AllowEpollWait()
125 .AllowEventFd()
126 .AllowGetIDs()
127 .AllowHandleSignals()
128 .AllowPipe()
129 .AllowPrctlSetName()
130 .AllowSafeFcntl()
131 .AllowSelect()
132 .AllowSleep()
133 .AllowSyscall(__NR_accept)
134 .AllowSyscall(__NR_accept4)
135 .AllowSyscall(__NR_bind)
136 .AllowSyscall(__NR_clone) // Multithreading
137 .AllowSyscall(__NR_connect)
138 .AllowSyscall(__NR_ftruncate)
139 .AllowSyscall(__NR_getpeername)
140 .AllowSyscall(__NR_getsockname)
141 .AllowSyscall(__NR_listen)
142 .AllowSyscall(__NR_memfd_create)
143 .AllowSyscall(__NR_recvfrom)
144 .AllowSyscall(__NR_recvmsg)
145 .AllowSyscall(__NR_sched_get_priority_max)
146 .AllowSyscall(__NR_sched_get_priority_min)
147 .AllowSyscall(__NR_sched_getparam)
148 .AllowSyscall(__NR_sched_getscheduler)
149 .AllowSyscall(__NR_sched_setscheduler)
150 .AllowSyscall(__NR_sched_yield)
151 .AllowSyscall(__NR_sendmsg)
152 .AllowSyscall(__NR_sendmmsg)
153 .AllowSyscall(__NR_sendto)
154 .AllowSyscall(__NR_shutdown)
155 .AllowSyscall(__NR_socketpair)
156 .AllowTCGETS();
157 }
158
159 } // namespace cuttlefish::process_sandboxer
160