2018-04-27 17:37:02 +00:00
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// Copyright 2018 Google Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// +build amd64
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package seccomp
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import (
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"syscall"
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"unsafe"
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"gvisor.googlesource.com/gvisor/pkg/abi/linux"
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)
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// sockFprog is sock_fprog taken from <linux/filter.h>.
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type sockFprog struct {
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Len uint16
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pad [6]byte
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Filter *linux.BPFInstruction
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}
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2018-10-11 05:39:32 +00:00
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// SetFilter installs the given BPF program.
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//
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// This is safe to call from an afterFork context.
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//
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//go:nosplit
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func SetFilter(instrs []linux.BPFInstruction) syscall.Errno {
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2018-04-27 17:37:02 +00:00
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// SYS_SECCOMP is not available in syscall package.
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const SYS_SECCOMP = 317
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// PR_SET_NO_NEW_PRIVS is required in order to enable seccomp. See seccomp(2) for details.
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2018-10-11 05:39:32 +00:00
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if _, _, errno := syscall.RawSyscall(syscall.SYS_PRCTL, linux.PR_SET_NO_NEW_PRIVS, 1, 0); errno != 0 {
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return errno
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2018-04-27 17:37:02 +00:00
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}
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// TODO: Use SECCOMP_FILTER_FLAG_KILL_PROCESS when available.
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2018-10-11 05:39:32 +00:00
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sockProg := sockFprog{
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Len: uint16(len(instrs)),
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Filter: (*linux.BPFInstruction)(unsafe.Pointer(&instrs[0])),
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2018-04-27 17:37:02 +00:00
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}
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2018-10-11 05:39:32 +00:00
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if _, _, errno := syscall.RawSyscall(SYS_SECCOMP, linux.SECCOMP_SET_MODE_FILTER, linux.SECCOMP_FILTER_FLAG_TSYNC, uintptr(unsafe.Pointer(&sockProg))); errno != 0 {
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return errno
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}
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return 0
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2018-04-27 17:37:02 +00:00
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}
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