Commit 722b0e32 authored by Cuong Manh Le's avatar Cuong Manh Le Committed by Matthew Dempsky

syscall: make convertFromDirents11 checkptr safe

Fixes #35092

Change-Id: I8f1ee2b79d42b2291548fd5645940a61f6d67582
Reviewed-on: https://go-review.googlesource.com/c/go/+/202878
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: default avatarMatthew Dempsky <mdempsky@google.com>
parent 68981bf3
......@@ -381,8 +381,12 @@ func convertFromDirents11(buf []byte, old []byte) int {
dstPos := 0
srcPos := 0
for dstPos+fixedSize < len(buf) && srcPos+oldFixedSize < len(old) {
dstDirent := (*Dirent)(unsafe.Pointer(&buf[dstPos]))
srcDirent := (*dirent_freebsd11)(unsafe.Pointer(&old[srcPos]))
var dstDirent Dirent
var srcDirent dirent_freebsd11
// If multiple direntries are written, sometimes when we reach the final one,
// we may have cap of old less than size of dirent_freebsd11.
copy((*[unsafe.Sizeof(srcDirent)]byte)(unsafe.Pointer(&srcDirent))[:], old[srcPos:])
reclen := roundup(fixedSize+int(srcDirent.Namlen)+1, 8)
if dstPos+reclen > len(buf) {
......@@ -398,6 +402,7 @@ func convertFromDirents11(buf []byte, old []byte) int {
dstDirent.Pad1 = 0
copy(dstDirent.Name[:], srcDirent.Name[:srcDirent.Namlen])
copy(buf[dstPos:], (*[unsafe.Sizeof(dstDirent)]byte)(unsafe.Pointer(&dstDirent))[:])
padding := buf[dstPos+fixedSize+int(dstDirent.Namlen) : dstPos+reclen]
for i := range padding {
padding[i] = 0
......
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