60 lines
1.1 KiB
Go
60 lines
1.1 KiB
Go
// Copyright 2019 the Go-FUSE Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package internal
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import (
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"os/user"
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"strconv"
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)
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// HasAccess tests if a caller can access a file with permissions
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// `perm` in mode `mask`
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func HasAccess(callerUid, callerGid, fileUid, fileGid uint32, perm uint32, mask uint32) bool {
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if callerUid == 0 {
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// root can do anything.
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return true
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}
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mask = mask & 7
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if mask == 0 {
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return true
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}
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if callerUid == fileUid {
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if perm&(mask<<6) != 0 {
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return true
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}
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}
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if callerGid == fileGid {
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if perm&(mask<<3) != 0 {
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return true
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}
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}
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if perm&mask != 0 {
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return true
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}
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// Check other groups.
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if perm&(mask<<3) == 0 {
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// avoid expensive lookup if it's not allowed anyway
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return false
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}
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u, err := user.LookupId(strconv.Itoa(int(callerUid)))
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if err != nil {
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return false
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}
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gs, err := u.GroupIds()
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if err != nil {
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return false
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}
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fileGidStr := strconv.Itoa(int(fileGid))
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for _, gidStr := range gs {
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if gidStr == fileGidStr {
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return true
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}
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}
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return false
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}
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