1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
|
// Copyright 2019 the Go-FUSE Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package internal
import (
"os/user"
"strconv"
)
// HasAccess tests if a caller can access a file with permissions
// `perm` in mode `mask`
func HasAccess(callerUid, callerGid, fileUid, fileGid uint32, perm uint32, mask uint32) bool {
if callerUid == 0 {
// root can do anything.
return true
}
mask = mask & 7
if mask == 0 {
return true
}
if callerUid == fileUid {
if perm&(mask<<6) != 0 {
return true
}
}
if callerGid == fileGid {
if perm&(mask<<3) != 0 {
return true
}
}
if perm&mask != 0 {
return true
}
// Check other groups.
if perm&(mask<<3) == 0 {
// avoid expensive lookup if it's not allowed anyway
return false
}
u, err := user.LookupId(strconv.Itoa(int(callerUid)))
if err != nil {
return false
}
gs, err := u.GroupIds()
if err != nil {
return false
}
fileGidStr := strconv.Itoa(int(fileGid))
for _, gidStr := range gs {
if gidStr == fileGidStr {
return true
}
}
return false
}
|
