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pledge_openbsd.go (2385B)

      1 // Copyright 2016 The Go Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style
      3 // license that can be found in the LICENSE file.
      4 
      5 package unix
      6 
      7 import (
      8 	"errors"
      9 	"fmt"
     10 	"strconv"
     11 )
     12 
     13 // Pledge implements the pledge syscall.
     14 //
     15 // This changes both the promises and execpromises; use PledgePromises or
     16 // PledgeExecpromises to only change the promises or execpromises
     17 // respectively.
     18 //
     19 // For more information see pledge(2).
     20 func Pledge(promises, execpromises string) error {
     21 	if err := pledgeAvailable(); err != nil {
     22 		return err
     23 	}
     24 
     25 	pptr, err := BytePtrFromString(promises)
     26 	if err != nil {
     27 		return err
     28 	}
     29 
     30 	exptr, err := BytePtrFromString(execpromises)
     31 	if err != nil {
     32 		return err
     33 	}
     34 
     35 	return pledge(pptr, exptr)
     36 }
     37 
     38 // PledgePromises implements the pledge syscall.
     39 //
     40 // This changes the promises and leaves the execpromises untouched.
     41 //
     42 // For more information see pledge(2).
     43 func PledgePromises(promises string) error {
     44 	if err := pledgeAvailable(); err != nil {
     45 		return err
     46 	}
     47 
     48 	pptr, err := BytePtrFromString(promises)
     49 	if err != nil {
     50 		return err
     51 	}
     52 
     53 	return pledge(pptr, nil)
     54 }
     55 
     56 // PledgeExecpromises implements the pledge syscall.
     57 //
     58 // This changes the execpromises and leaves the promises untouched.
     59 //
     60 // For more information see pledge(2).
     61 func PledgeExecpromises(execpromises string) error {
     62 	if err := pledgeAvailable(); err != nil {
     63 		return err
     64 	}
     65 
     66 	exptr, err := BytePtrFromString(execpromises)
     67 	if err != nil {
     68 		return err
     69 	}
     70 
     71 	return pledge(nil, exptr)
     72 }
     73 
     74 // majmin returns major and minor version number for an OpenBSD system.
     75 func majmin() (major int, minor int, err error) {
     76 	var v Utsname
     77 	err = Uname(&v)
     78 	if err != nil {
     79 		return
     80 	}
     81 
     82 	major, err = strconv.Atoi(string(v.Release[0]))
     83 	if err != nil {
     84 		err = errors.New("cannot parse major version number returned by uname")
     85 		return
     86 	}
     87 
     88 	minor, err = strconv.Atoi(string(v.Release[2]))
     89 	if err != nil {
     90 		err = errors.New("cannot parse minor version number returned by uname")
     91 		return
     92 	}
     93 
     94 	return
     95 }
     96 
     97 // pledgeAvailable checks for availability of the pledge(2) syscall
     98 // based on the running OpenBSD version.
     99 func pledgeAvailable() error {
    100 	maj, min, err := majmin()
    101 	if err != nil {
    102 		return err
    103 	}
    104 
    105 	// Require OpenBSD 6.4 as a minimum.
    106 	if maj < 6 || (maj == 6 && min <= 3) {
    107 		return fmt.Errorf("cannot call Pledge on OpenBSD %d.%d", maj, min)
    108 	}
    109 
    110 	return nil
    111 }