rss-tools/vendor/golang.org/x/sys/unix/cap_freebsd.go (view raw)
| 1 | // Copyright 2017 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 | //go:build freebsd |
| 6 | |
| 7 | package unix |
| 8 | |
| 9 | import ( |
| 10 | "errors" |
| 11 | "fmt" |
| 12 | ) |
| 13 | |
| 14 | // Go implementation of C mostly found in /usr/src/sys/kern/subr_capability.c |
| 15 | |
| 16 | const ( |
| 17 | // This is the version of CapRights this package understands. See C implementation for parallels. |
| 18 | capRightsGoVersion = CAP_RIGHTS_VERSION_00 |
| 19 | capArSizeMin = CAP_RIGHTS_VERSION_00 + 2 |
| 20 | capArSizeMax = capRightsGoVersion + 2 |
| 21 | ) |
| 22 | |
| 23 | var ( |
| 24 | bit2idx = []int{ |
| 25 | -1, 0, 1, -1, 2, -1, -1, -1, 3, -1, -1, -1, -1, -1, -1, -1, |
| 26 | 4, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
| 27 | } |
| 28 | ) |
| 29 | |
| 30 | func capidxbit(right uint64) int { |
| 31 | return int((right >> 57) & 0x1f) |
| 32 | } |
| 33 | |
| 34 | func rightToIndex(right uint64) (int, error) { |
| 35 | idx := capidxbit(right) |
| 36 | if idx < 0 || idx >= len(bit2idx) { |
| 37 | return -2, fmt.Errorf("index for right 0x%x out of range", right) |
| 38 | } |
| 39 | return bit2idx[idx], nil |
| 40 | } |
| 41 | |
| 42 | func caprver(right uint64) int { |
| 43 | return int(right >> 62) |
| 44 | } |
| 45 | |
| 46 | func capver(rights *CapRights) int { |
| 47 | return caprver(rights.Rights[0]) |
| 48 | } |
| 49 | |
| 50 | func caparsize(rights *CapRights) int { |
| 51 | return capver(rights) + 2 |
| 52 | } |
| 53 | |
| 54 | // CapRightsSet sets the permissions in setrights in rights. |
| 55 | func CapRightsSet(rights *CapRights, setrights []uint64) error { |
| 56 | // This is essentially a copy of cap_rights_vset() |
| 57 | if capver(rights) != CAP_RIGHTS_VERSION_00 { |
| 58 | return fmt.Errorf("bad rights version %d", capver(rights)) |
| 59 | } |
| 60 | |
| 61 | n := caparsize(rights) |
| 62 | if n < capArSizeMin || n > capArSizeMax { |
| 63 | return errors.New("bad rights size") |
| 64 | } |
| 65 | |
| 66 | for _, right := range setrights { |
| 67 | if caprver(right) != CAP_RIGHTS_VERSION_00 { |
| 68 | return errors.New("bad right version") |
| 69 | } |
| 70 | i, err := rightToIndex(right) |
| 71 | if err != nil { |
| 72 | return err |
| 73 | } |
| 74 | if i >= n { |
| 75 | return errors.New("index overflow") |
| 76 | } |
| 77 | if capidxbit(rights.Rights[i]) != capidxbit(right) { |
| 78 | return errors.New("index mismatch") |
| 79 | } |
| 80 | rights.Rights[i] |= right |
| 81 | if capidxbit(rights.Rights[i]) != capidxbit(right) { |
| 82 | return errors.New("index mismatch (after assign)") |
| 83 | } |
| 84 | } |
| 85 | |
| 86 | return nil |
| 87 | } |
| 88 | |
| 89 | // CapRightsClear clears the permissions in clearrights from rights. |
| 90 | func CapRightsClear(rights *CapRights, clearrights []uint64) error { |
| 91 | // This is essentially a copy of cap_rights_vclear() |
| 92 | if capver(rights) != CAP_RIGHTS_VERSION_00 { |
| 93 | return fmt.Errorf("bad rights version %d", capver(rights)) |
| 94 | } |
| 95 | |
| 96 | n := caparsize(rights) |
| 97 | if n < capArSizeMin || n > capArSizeMax { |
| 98 | return errors.New("bad rights size") |
| 99 | } |
| 100 | |
| 101 | for _, right := range clearrights { |
| 102 | if caprver(right) != CAP_RIGHTS_VERSION_00 { |
| 103 | return errors.New("bad right version") |
| 104 | } |
| 105 | i, err := rightToIndex(right) |
| 106 | if err != nil { |
| 107 | return err |
| 108 | } |
| 109 | if i >= n { |
| 110 | return errors.New("index overflow") |
| 111 | } |
| 112 | if capidxbit(rights.Rights[i]) != capidxbit(right) { |
| 113 | return errors.New("index mismatch") |
| 114 | } |
| 115 | rights.Rights[i] &= ^(right & 0x01FFFFFFFFFFFFFF) |
| 116 | if capidxbit(rights.Rights[i]) != capidxbit(right) { |
| 117 | return errors.New("index mismatch (after assign)") |
| 118 | } |
| 119 | } |
| 120 | |
| 121 | return nil |
| 122 | } |
| 123 | |
| 124 | // CapRightsIsSet checks whether all the permissions in setrights are present in rights. |
| 125 | func CapRightsIsSet(rights *CapRights, setrights []uint64) (bool, error) { |
| 126 | // This is essentially a copy of cap_rights_is_vset() |
| 127 | if capver(rights) != CAP_RIGHTS_VERSION_00 { |
| 128 | return false, fmt.Errorf("bad rights version %d", capver(rights)) |
| 129 | } |
| 130 | |
| 131 | n := caparsize(rights) |
| 132 | if n < capArSizeMin || n > capArSizeMax { |
| 133 | return false, errors.New("bad rights size") |
| 134 | } |
| 135 | |
| 136 | for _, right := range setrights { |
| 137 | if caprver(right) != CAP_RIGHTS_VERSION_00 { |
| 138 | return false, errors.New("bad right version") |
| 139 | } |
| 140 | i, err := rightToIndex(right) |
| 141 | if err != nil { |
| 142 | return false, err |
| 143 | } |
| 144 | if i >= n { |
| 145 | return false, errors.New("index overflow") |
| 146 | } |
| 147 | if capidxbit(rights.Rights[i]) != capidxbit(right) { |
| 148 | return false, errors.New("index mismatch") |
| 149 | } |
| 150 | if (rights.Rights[i] & right) != right { |
| 151 | return false, nil |
| 152 | } |
| 153 | } |
| 154 | |
| 155 | return true, nil |
| 156 | } |
| 157 | |
| 158 | func capright(idx uint64, bit uint64) uint64 { |
| 159 | return ((1 << (57 + idx)) | bit) |
| 160 | } |
| 161 | |
| 162 | // CapRightsInit returns a pointer to an initialised CapRights structure filled with rights. |
| 163 | // See man cap_rights_init(3) and rights(4). |
| 164 | func CapRightsInit(rights []uint64) (*CapRights, error) { |
| 165 | var r CapRights |
| 166 | r.Rights[0] = (capRightsGoVersion << 62) | capright(0, 0) |
| 167 | r.Rights[1] = capright(1, 0) |
| 168 | |
| 169 | err := CapRightsSet(&r, rights) |
| 170 | if err != nil { |
| 171 | return nil, err |
| 172 | } |
| 173 | return &r, nil |
| 174 | } |
| 175 | |
| 176 | // CapRightsLimit reduces the operations permitted on fd to at most those contained in rights. |
| 177 | // The capability rights on fd can never be increased by CapRightsLimit. |
| 178 | // See man cap_rights_limit(2) and rights(4). |
| 179 | func CapRightsLimit(fd uintptr, rights *CapRights) error { |
| 180 | return capRightsLimit(int(fd), rights) |
| 181 | } |
| 182 | |
| 183 | // CapRightsGet returns a CapRights structure containing the operations permitted on fd. |
| 184 | // See man cap_rights_get(3) and rights(4). |
| 185 | func CapRightsGet(fd uintptr) (*CapRights, error) { |
| 186 | r, err := CapRightsInit(nil) |
| 187 | if err != nil { |
| 188 | return nil, err |
| 189 | } |
| 190 | err = capRightsGet(capRightsGoVersion, int(fd), r) |
| 191 | if err != nil { |
| 192 | return nil, err |
| 193 | } |
| 194 | return r, nil |
| 195 | } |