mirror of
https://github.com/octoleo/restic.git
synced 2024-12-22 10:58:55 +00:00
aaf5254e26
The old version was taken from an MPL-licensed library. This is a cleanroom implementation. The code is shorter and it's now explicit that only Linux ACLs are supported.
89 lines
2.0 KiB
Go
89 lines
2.0 KiB
Go
package dump
|
|
|
|
import (
|
|
"encoding/binary"
|
|
"errors"
|
|
"strconv"
|
|
)
|
|
|
|
const (
|
|
// Permissions
|
|
aclPermRead = 0x4
|
|
aclPermWrite = 0x2
|
|
aclPermExecute = 0x1
|
|
|
|
// Tags
|
|
aclTagUserObj = 0x01 // Owner.
|
|
aclTagUser = 0x02
|
|
aclTagGroupObj = 0x04 // Owning group.
|
|
aclTagGroup = 0x08
|
|
aclTagMask = 0x10
|
|
aclTagOther = 0x20
|
|
)
|
|
|
|
// formatLinuxACL converts a Linux ACL from its binary format to the POSIX.1e
|
|
// long text format.
|
|
//
|
|
// User and group IDs are printed in decimal, because we may be dumping
|
|
// a snapshot from a different machine.
|
|
//
|
|
// https://man7.org/linux/man-pages/man5/acl.5.html
|
|
// https://savannah.nongnu.org/projects/acl
|
|
// https://simson.net/ref/1997/posix_1003.1e-990310.pdf
|
|
func formatLinuxACL(acl []byte) (string, error) {
|
|
if len(acl)-4 < 0 || (len(acl)-4)%8 != 0 {
|
|
return "", errors.New("wrong length")
|
|
}
|
|
version := binary.LittleEndian.Uint32(acl)
|
|
if version != 2 {
|
|
return "", errors.New("unsupported ACL format version")
|
|
}
|
|
acl = acl[4:]
|
|
|
|
text := make([]byte, 0, 2*len(acl))
|
|
|
|
for ; len(acl) >= 8; acl = acl[8:] {
|
|
tag := binary.LittleEndian.Uint16(acl)
|
|
perm := binary.LittleEndian.Uint16(acl[2:])
|
|
id := binary.LittleEndian.Uint32(acl[4:])
|
|
|
|
switch tag {
|
|
case aclTagUserObj:
|
|
text = append(text, "user:"...)
|
|
case aclTagUser:
|
|
text = append(text, "user:"...)
|
|
text = strconv.AppendUint(text, uint64(id), 10)
|
|
case aclTagGroupObj:
|
|
text = append(text, "group:"...)
|
|
case aclTagGroup:
|
|
text = append(text, "group:"...)
|
|
text = strconv.AppendUint(text, uint64(id), 10)
|
|
case aclTagMask:
|
|
text = append(text, "mask:"...)
|
|
case aclTagOther:
|
|
text = append(text, "other:"...)
|
|
default:
|
|
return "", errors.New("unknown tag")
|
|
}
|
|
text = append(text, ':')
|
|
text = append(text, aclPermText(perm)...)
|
|
text = append(text, '\n')
|
|
}
|
|
|
|
return string(text), nil
|
|
}
|
|
|
|
func aclPermText(p uint16) []byte {
|
|
s := []byte("---")
|
|
if p&aclPermRead != 0 {
|
|
s[0] = 'r'
|
|
}
|
|
if p&aclPermWrite != 0 {
|
|
s[1] = 'w'
|
|
}
|
|
if p&aclPermExecute != 0 {
|
|
s[2] = 'x'
|
|
}
|
|
return s
|
|
}
|