Serge Bazanski | cc25bdf | 2018-10-25 14:02:58 +0200 | [diff] [blame] | 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 | // +build openbsd |
| 6 | // +build 386 amd64 arm |
| 7 | |
| 8 | package unix |
| 9 | |
| 10 | import ( |
| 11 | "errors" |
| 12 | "fmt" |
| 13 | "strconv" |
| 14 | "syscall" |
| 15 | "unsafe" |
| 16 | ) |
| 17 | |
| 18 | // Pledge implements the pledge syscall. |
| 19 | // |
| 20 | // The pledge syscall does not accept execpromises on OpenBSD releases |
| 21 | // before 6.3. |
| 22 | // |
| 23 | // execpromises must be empty when Pledge is called on OpenBSD |
| 24 | // releases predating 6.3, otherwise an error will be returned. |
| 25 | // |
| 26 | // For more information see pledge(2). |
| 27 | func Pledge(promises, execpromises string) error { |
| 28 | maj, min, err := majmin() |
| 29 | if err != nil { |
| 30 | return err |
| 31 | } |
| 32 | |
| 33 | // If OpenBSD <= 5.9, pledge is not available. |
| 34 | if (maj == 5 && min != 9) || maj < 5 { |
| 35 | return fmt.Errorf("pledge syscall is not available on OpenBSD %d.%d", maj, min) |
| 36 | } |
| 37 | |
| 38 | // If OpenBSD <= 6.2 and execpromises is not empty |
| 39 | // return an error - execpromises is not available before 6.3 |
| 40 | if (maj < 6 || (maj == 6 && min <= 2)) && execpromises != "" { |
| 41 | return fmt.Errorf("cannot use execpromises on OpenBSD %d.%d", maj, min) |
| 42 | } |
| 43 | |
| 44 | pptr, err := syscall.BytePtrFromString(promises) |
| 45 | if err != nil { |
| 46 | return err |
| 47 | } |
| 48 | |
| 49 | // This variable will hold either a nil unsafe.Pointer or |
| 50 | // an unsafe.Pointer to a string (execpromises). |
| 51 | var expr unsafe.Pointer |
| 52 | |
| 53 | // If we're running on OpenBSD > 6.2, pass execpromises to the syscall. |
| 54 | if maj > 6 || (maj == 6 && min > 2) { |
| 55 | exptr, err := syscall.BytePtrFromString(execpromises) |
| 56 | if err != nil { |
| 57 | return err |
| 58 | } |
| 59 | expr = unsafe.Pointer(exptr) |
| 60 | } |
| 61 | |
| 62 | _, _, e := syscall.Syscall(SYS_PLEDGE, uintptr(unsafe.Pointer(pptr)), uintptr(expr), 0) |
| 63 | if e != 0 { |
| 64 | return e |
| 65 | } |
| 66 | |
| 67 | return nil |
| 68 | } |
| 69 | |
| 70 | // majmin returns major and minor version number for an OpenBSD system. |
| 71 | func majmin() (major int, minor int, err error) { |
| 72 | var v Utsname |
| 73 | err = Uname(&v) |
| 74 | if err != nil { |
| 75 | return |
| 76 | } |
| 77 | |
| 78 | major, err = strconv.Atoi(string(v.Release[0])) |
| 79 | if err != nil { |
| 80 | err = errors.New("cannot parse major version number returned by uname") |
| 81 | return |
| 82 | } |
| 83 | |
| 84 | minor, err = strconv.Atoi(string(v.Release[2])) |
| 85 | if err != nil { |
| 86 | err = errors.New("cannot parse minor version number returned by uname") |
| 87 | return |
| 88 | } |
| 89 | |
| 90 | return |
| 91 | } |