95 lines
2.2 KiB
Go
95 lines
2.2 KiB
Go
// Copyright 2016 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build openbsd
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// +build 386 amd64 arm
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package unix
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import (
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"errors"
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"fmt"
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"strconv"
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"syscall"
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"unsafe"
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)
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const (
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_SYS_PLEDGE = 108
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)
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// Pledge implements the pledge syscall.
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//
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// The pledge syscall does not accept execpromises on OpenBSD releases
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// before 6.3.
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//
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// execpromises must be empty when Pledge is called on OpenBSD
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// releases predating 6.3, otherwise an error will be returned.
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//
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// For more information see pledge(2).
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func Pledge(promises, execpromises string) error {
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maj, min, err := majmin()
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if err != nil {
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return err
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}
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// If OpenBSD <= 5.9, pledge is not available.
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if (maj == 5 && min != 9) || maj < 5 {
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return fmt.Errorf("pledge syscall is not available on OpenBSD %d.%d", maj, min)
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}
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// If OpenBSD <= 6.2 and execpromises is not empty
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// return an error - execpromises is not available before 6.3
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if (maj < 6 || (maj == 6 && min <= 2)) && execpromises != "" {
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return fmt.Errorf("cannot use execpromises on OpenBSD %d.%d", maj, min)
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}
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pptr, err := syscall.BytePtrFromString(promises)
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if err != nil {
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return err
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}
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// This variable will hold either a nil unsafe.Pointer or
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// an unsafe.Pointer to a string (execpromises).
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var expr unsafe.Pointer
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// If we're running on OpenBSD > 6.2, pass execpromises to the syscall.
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if maj > 6 || (maj == 6 && min > 2) {
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exptr, err := syscall.BytePtrFromString(execpromises)
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if err != nil {
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return err
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}
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expr = unsafe.Pointer(exptr)
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}
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_, _, e := syscall.Syscall(_SYS_PLEDGE, uintptr(unsafe.Pointer(pptr)), uintptr(expr), 0)
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if e != 0 {
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return e
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}
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return nil
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}
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// majmin returns major and minor version number for an OpenBSD system.
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func majmin() (major int, minor int, err error) {
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var v Utsname
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err = Uname(&v)
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if err != nil {
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return
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}
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major, err = strconv.Atoi(string(v.Release[0]))
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if err != nil {
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err = errors.New("cannot parse major version number returned by uname")
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return
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}
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minor, err = strconv.Atoi(string(v.Release[2]))
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if err != nil {
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err = errors.New("cannot parse minor version number returned by uname")
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return
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}
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return
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}
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