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// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "sandbox/policy/linux/bpf_nearby_policy_linux.h"
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <sys/socket.h>
#include "sandbox/linux/seccomp-bpf-helpers/sigsys_handlers.h"
#include "sandbox/linux/system_headers/linux_syscalls.h"
#include "sandbox/policy/linux/sandbox_linux.h"
using sandbox::bpf_dsl::AllOf;
using sandbox::bpf_dsl::Allow;
using sandbox::bpf_dsl::Arg;
using sandbox::bpf_dsl::If;
using sandbox::bpf_dsl::ResultExpr;
namespace sandbox::policy {
namespace {
ResultExpr RestrictSocketForNearbyProcess() {
Arg<int> domain(0);
Arg<int> type(1);
Arg<int> protocol(2);
// This is the explicit socket configuration used by `WifiDirectMedium`.
return If(AllOf(domain == AF_INET, type == SOCK_STREAM,
protocol == IPPROTO_TCP),
Allow())
.Else(CrashSIGSYSSocket());
}
ResultExpr RestrictSetSockoptForNearbyProcess() {
Arg<int> level(1);
Arg<int> optname(2);
ResultExpr socket_optname_switch =
Switch(optname)
.Cases({SO_KEEPALIVE, SO_REUSEADDR, SO_REUSEPORT, SO_RCVBUF,
SO_SNDBUF, SO_BROADCAST},
Allow())
.Default(CrashSIGSYSSockopt());
ResultExpr tcp_optname_switch =
Switch(optname)
.Cases({TCP_KEEPIDLE, TCP_KEEPINTVL, TCP_NODELAY}, Allow())
.Default(CrashSIGSYSSockopt());
return Switch(level)
.Case(SOL_SOCKET, socket_optname_switch)
.Case(SOL_TCP, tcp_optname_switch)
.Default(CrashSIGSYSSockopt());
}
} // namespace
NearbyProcessPolicy::NearbyProcessPolicy() = default;
NearbyProcessPolicy::~NearbyProcessPolicy() = default;
ResultExpr NearbyProcessPolicy::EvaluateSyscall(int sysno) const {
switch (sysno) {
case __NR_accept:
case __NR_accept4:
case __NR_connect:
case __NR_bind:
case __NR_listen:
case __NR_getsockname:
case __NR_sendmmsg:
case __NR_getsockopt:
return Allow();
case __NR_setsockopt:
return RestrictSetSockoptForNearbyProcess();
case __NR_socket:
return RestrictSocketForNearbyProcess();
default:
// Default on the baseline policy.
return BPFBasePolicy::EvaluateSyscall(sysno);
}
}
} // namespace sandbox::policy
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