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 <netinet/ip_icmp.h>
21 #include <sys/ioctl.h>
22 #include <sys/mman.h>
23 #include <sys/socket.h>
24 #include <sys/syscall.h>
25
26 #include <vector>
27
28 #include <sandboxed_api/sandbox2/policybuilder.h>
29 #include <sandboxed_api/sandbox2/util/bpf_helper.h>
30
31 namespace cuttlefish::process_sandboxer {
32
CasimirPolicy(const HostInfo & host)33 sandbox2::PolicyBuilder CasimirPolicy(const HostInfo& host) {
34 return BaselinePolicy(host, host.HostToolExe("casimir"))
35 // `librustutils::inherited_fd` scans `/proc/self/fd` for open FDs.
36 // Mounting a subset of `/proc/` is invalid.
37 .AddDirectory("/proc", /* is_ro = */ false)
38 .AddDirectory(host.EnvironmentsUdsDir(), /* is_ro= */ false)
39 .AddPolicyOnMmap([](bpf_labels& labels) -> std::vector<sock_filter> {
40 return {
41 ARG_32(2), // prot
42 JNE32(PROT_READ | PROT_WRITE, JUMP(&labels, cf_casimir_mmap_end)),
43 ARG_32(3), // flags
44 JEQ32(MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, ALLOW),
45 LABEL(&labels, cf_casimir_mmap_end),
46 };
47 })
48 .AddPolicyOnSyscall(
49 __NR_setsockopt,
50 [](bpf_labels& labels) -> std::vector<sock_filter> {
51 return {
52 ARG_32(1), // level
53 JNE32(IPPROTO_ICMP, JUMP(&labels, cf_casimir_setsockopt_end)),
54 // IPPROTO_ICMP
55 ARG_32(2), // optname
56 JEQ32(ICMP_REDIR_NETTOS, ALLOW),
57 LABEL(&labels, cf_casimir_setsockopt_end)};
58 })
59 .AddPolicyOnSyscall(__NR_ioctl, {ARG_32(1), JEQ32(FIONBIO, ALLOW)})
60 .AddPolicyOnSyscall(__NR_socket, {ARG_32(0), JEQ32(AF_UNIX, ALLOW)})
61 .AllowEpoll()
62 .AllowEpollWait()
63 .AllowEventFd()
64 .AllowHandleSignals()
65 .AllowPrctlSetName()
66 .AllowReaddir()
67 .AllowSafeFcntl()
68 .AllowSyscall(__NR_accept4)
69 .AllowSyscall(__NR_bind)
70 .AllowSyscall(__NR_clone)
71 .AllowSyscall(__NR_listen)
72 // Uses GRND_INSECURE which is not covered by AllowGetRandom()
73 .AllowSyscall(__NR_getrandom)
74 .AllowSyscall(__NR_recvfrom)
75 .AllowSyscall(__NR_sendto)
76 .AllowSyscall(__NR_shutdown)
77 .AllowSyscall(__NR_statx); // Not covered by AllowStat
78 }
79
80 } // namespace cuttlefish::process_sandboxer
81