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go/internal/fastwalk/fastwalk_dirent_namlen_linux.go
Mikołaj Baranowski 5f9a541373 internal/fastwalk: avoid slice bounds out of range for long file names
Fixes golang/go#28715

Change-Id: Ibed78d2376f4ec010ee9e5e772069afd14fd5552
Reviewed-on: https://go-review.googlesource.com/c/148884
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-11-12 23:16:31 +00:00

30 lines
730 B
Go

// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build linux
// +build !appengine
package fastwalk
import (
"bytes"
"syscall"
"unsafe"
)
func direntNamlen(dirent *syscall.Dirent) uint64 {
const fixedHdr = uint16(unsafe.Offsetof(syscall.Dirent{}.Name))
nameBuf := (*[unsafe.Sizeof(dirent.Name)]byte)(unsafe.Pointer(&dirent.Name[0]))
const nameBufLen = uint16(len(nameBuf))
limit := dirent.Reclen - fixedHdr
if limit > nameBufLen {
limit = nameBufLen
}
nameLen := bytes.IndexByte(nameBuf[:limit], 0)
if nameLen < 0 {
panic("failed to find terminating 0 byte in dirent")
}
return uint64(nameLen)
}