[kirkstone][PATCH v2] go: fix CVE-2022-2879 and CVE-2022-41720


Sakib Sajal
 

Backport appropriate patches to fix CVE-2022-2879 and CVE-2022-41720.

Modified the original fix for CVE-2022-2879 to remove a testdata tarball
and any references to it since git binary diffs are not supported in
quilt.

Signed-off-by: Sakib Sajal <sakib.sajal@...>
---
meta/recipes-devtools/go/go-1.17.13.inc | 2 +
...01-archive-tar-limit-size-of-headers.patch | 177 ++++++
...d-escapes-from-os.DirFS-and-http.Dir.patch | 514 ++++++++++++++++++
3 files changed, 693 insertions(+)
create mode 100644 meta/recipes-devtools/go/go-1.18/0001-archive-tar-limit-size-of-headers.patch
create mode 100644 meta/recipes-devtools/go/go-1.18/0002-os-net-http-avoid-escapes-from-os.DirFS-and-http.Dir.patch

diff --git a/meta/recipes-devtools/go/go-1.17.13.inc b/meta/recipes-devtools/go/go-1.17.13.inc
index 99662bd298..a6081bdee7 100644
--- a/meta/recipes-devtools/go/go-1.17.13.inc
+++ b/meta/recipes-devtools/go/go-1.17.13.inc
@@ -20,6 +20,8 @@ SRC_URI += "\
file://0001-net-http-httputil-avoid-query-parameter-smuggling.patch \
file://CVE-2022-41715.patch \
file://CVE-2022-41717.patch \
+ file://0001-archive-tar-limit-size-of-headers.patch \
+ file://0002-os-net-http-avoid-escapes-from-os.DirFS-and-http.Dir.patch \
"
SRC_URI[main.sha256sum] = "a1a48b23afb206f95e7bbaa9b898d965f90826f6f1d1fc0c1d784ada0cd300fd"

diff --git a/meta/recipes-devtools/go/go-1.18/0001-archive-tar-limit-size-of-headers.patch b/meta/recipes-devtools/go/go-1.18/0001-archive-tar-limit-size-of-headers.patch
new file mode 100644
index 0000000000..0315e1a3ee
--- /dev/null
+++ b/meta/recipes-devtools/go/go-1.18/0001-archive-tar-limit-size-of-headers.patch
@@ -0,0 +1,177 @@
+From d064ed520a7cc6b480f9565e30751e695d394f4e Mon Sep 17 00:00:00 2001
+From: Damien Neil <dneil@...>
+Date: Fri, 2 Sep 2022 20:45:18 -0700
+Subject: [PATCH] archive/tar: limit size of headers
+
+Set a 1MiB limit on special file blocks (PAX headers, GNU long names,
+GNU link names), to avoid reading arbitrarily large amounts of data
+into memory.
+
+Thanks to Adam Korczynski (ADA Logics) and OSS-Fuzz for reporting
+this issue.
+
+Fixes CVE-2022-2879
+Updates #54853
+Fixes #55925
+
+Change-Id: I85136d6ff1e0af101a112190e027987ab4335680
+Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/1565555
+Reviewed-by: Tatiana Bradley <tatianabradley@...>
+Run-TryBot: Roland Shoemaker <bracewell@...>
+Reviewed-by: Roland Shoemaker <bracewell@...>
+(cherry picked from commit 6ee768cef6b82adf7a90dcf367a1699ef694f3b2)
+Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/1590622
+Reviewed-by: Damien Neil <dneil@...>
+Reviewed-by: Julie Qiu <julieqiu@...>
+Reviewed-on: https://go-review.googlesource.com/c/go/+/438500
+Reviewed-by: Dmitri Shuralyov <dmitshur@...>
+Reviewed-by: Carlos Amedee <carlos@...>
+Reviewed-by: Dmitri Shuralyov <dmitshur@...>
+Run-TryBot: Carlos Amedee <carlos@...>
+TryBot-Result: Gopher Robot <gobot@...>
+
+CVE: CVE-2022-2879
+Upstream-Status: Backport [0a723816cd205576945fa57fbdde7e6532d59d08]
+Signed-off-by: Sakib Sajal <sakib.sajal@...>
+---
+ src/archive/tar/format.go | 4 ++++
+ src/archive/tar/reader.go | 14 ++++++++++++--
+ src/archive/tar/reader_test.go | 8 +++++++-
+ src/archive/tar/writer.go | 3 +++
+ src/archive/tar/writer_test.go | 27 +++++++++++++++++++++++++++
+ 5 files changed, 53 insertions(+), 3 deletions(-)
+
+diff --git a/src/archive/tar/format.go b/src/archive/tar/format.go
+index cfe24a5..6642364 100644
+--- a/src/archive/tar/format.go
++++ b/src/archive/tar/format.go
+@@ -143,6 +143,10 @@ const (
+ blockSize = 512 // Size of each block in a tar stream
+ nameSize = 100 // Max length of the name field in USTAR format
+ prefixSize = 155 // Max length of the prefix field in USTAR format
++
++ // Max length of a special file (PAX header, GNU long name or link).
++ // This matches the limit used by libarchive.
++ maxSpecialFileSize = 1 << 20
+ )
+
+ // blockPadding computes the number of bytes needed to pad offset up to the
+diff --git a/src/archive/tar/reader.go b/src/archive/tar/reader.go
+index 1b1d5b4..f645af8 100644
+--- a/src/archive/tar/reader.go
++++ b/src/archive/tar/reader.go
+@@ -103,7 +103,7 @@ func (tr *Reader) next() (*Header, error) {
+ continue // This is a meta header affecting the next header
+ case TypeGNULongName, TypeGNULongLink:
+ format.mayOnlyBe(FormatGNU)
+- realname, err := io.ReadAll(tr)
++ realname, err := readSpecialFile(tr)
+ if err != nil {
+ return nil, err
+ }
+@@ -293,7 +293,7 @@ func mergePAX(hdr *Header, paxHdrs map[string]string) (err error) {
+ // parsePAX parses PAX headers.
+ // If an extended header (type 'x') is invalid, ErrHeader is returned
+ func parsePAX(r io.Reader) (map[string]string, error) {
+- buf, err := io.ReadAll(r)
++ buf, err := readSpecialFile(r)
+ if err != nil {
+ return nil, err
+ }
+@@ -826,6 +826,16 @@ func tryReadFull(r io.Reader, b []byte) (n int, err error) {
+ return n, err
+ }
+
++// readSpecialFile is like io.ReadAll except it returns
++// ErrFieldTooLong if more than maxSpecialFileSize is read.
++func readSpecialFile(r io.Reader) ([]byte, error) {
++ buf, err := io.ReadAll(io.LimitReader(r, maxSpecialFileSize+1))
++ if len(buf) > maxSpecialFileSize {
++ return nil, ErrFieldTooLong
++ }
++ return buf, err
++}
++
+ // discard skips n bytes in r, reporting an error if unable to do so.
+ func discard(r io.Reader, n int64) error {
+ // If possible, Seek to the last byte before the end of the data section.
+diff --git a/src/archive/tar/reader_test.go b/src/archive/tar/reader_test.go
+index 789ddc1..926dc3d 100644
+--- a/src/archive/tar/reader_test.go
++++ b/src/archive/tar/reader_test.go
+@@ -6,6 +6,7 @@ package tar
+
+ import (
+ "bytes"
++ "compress/bzip2"
+ "crypto/md5"
+ "errors"
+ "fmt"
+@@ -625,9 +626,14 @@ func TestReader(t *testing.T) {
+ }
+ defer f.Close()
+
++ var fr io.Reader = f
++ if strings.HasSuffix(v.file, ".bz2") {
++ fr = bzip2.NewReader(fr)
++ }
++
+ // Capture all headers and checksums.
+ var (
+- tr = NewReader(f)
++ tr = NewReader(fr)
+ hdrs []*Header
+ chksums []string
+ rdbuf = make([]byte, 8)
+diff --git a/src/archive/tar/writer.go b/src/archive/tar/writer.go
+index e80498d..893eac0 100644
+--- a/src/archive/tar/writer.go
++++ b/src/archive/tar/writer.go
+@@ -199,6 +199,9 @@ func (tw *Writer) writePAXHeader(hdr *Header, paxHdrs map[string]string) error {
+ flag = TypeXHeader
+ }
+ data := buf.String()
++ if len(data) > maxSpecialFileSize {
++ return ErrFieldTooLong
++ }
+ if err := tw.writeRawFile(name, data, flag, FormatPAX); err != nil || isGlobal {
+ return err // Global headers return here
+ }
+diff --git a/src/archive/tar/writer_test.go b/src/archive/tar/writer_test.go
+index a00f02d..4e709e5 100644
+--- a/src/archive/tar/writer_test.go
++++ b/src/archive/tar/writer_test.go
+@@ -1006,6 +1006,33 @@ func TestIssue12594(t *testing.T) {
+ }
+ }
+
++func TestWriteLongHeader(t *testing.T) {
++ for _, test := range []struct {
++ name string
++ h *Header
++ }{{
++ name: "name too long",
++ h: &Header{Name: strings.Repeat("a", maxSpecialFileSize)},
++ }, {
++ name: "linkname too long",
++ h: &Header{Linkname: strings.Repeat("a", maxSpecialFileSize)},
++ }, {
++ name: "uname too long",
++ h: &Header{Uname: strings.Repeat("a", maxSpecialFileSize)},
++ }, {
++ name: "gname too long",
++ h: &Header{Gname: strings.Repeat("a", maxSpecialFileSize)},
++ }, {
++ name: "PAX header too long",
++ h: &Header{PAXRecords: map[string]string{"GOLANG.x": strings.Repeat("a", maxSpecialFileSize)}},
++ }} {
++ w := NewWriter(io.Discard)
++ if err := w.WriteHeader(test.h); err != ErrFieldTooLong {
++ t.Errorf("%v: w.WriteHeader() = %v, want ErrFieldTooLong", test.name, err)
++ }
++ }
++}
++
+ // testNonEmptyWriter wraps an io.Writer and ensures that
+ // Write is never called with an empty buffer.
+ type testNonEmptyWriter struct{ io.Writer }
diff --git a/meta/recipes-devtools/go/go-1.18/0002-os-net-http-avoid-escapes-from-os.DirFS-and-http.Dir.patch b/meta/recipes-devtools/go/go-1.18/0002-os-net-http-avoid-escapes-from-os.DirFS-and-http.Dir.patch
new file mode 100644
index 0000000000..6c2e8804b3
--- /dev/null
+++ b/meta/recipes-devtools/go/go-1.18/0002-os-net-http-avoid-escapes-from-os.DirFS-and-http.Dir.patch
@@ -0,0 +1,514 @@
+From f8896a97a0630b0f2f8c488310147f7f20b3ec7d Mon Sep 17 00:00:00 2001
+From: Damien Neil <dneil@...>
+Date: Thu, 10 Nov 2022 12:16:27 -0800
+Subject: [PATCH] os, net/http: avoid escapes from os.DirFS and http.Dir on
+ Windows
+
+Do not permit access to Windows reserved device names (NUL, COM1, etc.)
+via os.DirFS and http.Dir filesystems.
+
+Avoid escapes from os.DirFS(`\`) on Windows. DirFS would join the
+the root to the relative path with a path separator, making
+os.DirFS(`\`).Open(`/foo/bar`) open the path `\\foo\bar`, which is
+a UNC name. Not only does this not open the intended file, but permits
+reference to any file on the system rather than only files on the
+current drive.
+
+Make os.DirFS("") invalid, with all file access failing. Previously,
+a root of "" was interpreted as "/", which is surprising and probably
+unintentional.
+
+Fixes CVE-2022-41720.
+Fixes #56694.
+
+Change-Id: I275b5fa391e6ad7404309ea98ccc97405942e0f0
+Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/1663832
+Reviewed-by: Julie Qiu <julieqiu@...>
+Reviewed-by: Tatiana Bradley <tatianabradley@...>
+Reviewed-on: https://go-review.googlesource.com/c/go/+/455360
+Reviewed-by: Michael Pratt <mpratt@...>
+TryBot-Result: Gopher Robot <gobot@...>
+Run-TryBot: Jenny Rakoczy <jenny@...>
+
+CVE: CVE-2022-41720
+Upstream-Status: Backport [7013a4f5f816af62033ad63dd06b77c30d7a62a7]
+Signed-off-by: Sakib Sajal <sakib.sajal@...>
+---
+ src/go/build/deps_test.go | 1 +
+ src/internal/safefilepath/path.go | 21 +++++
+ src/internal/safefilepath/path_other.go | 23 ++++++
+ src/internal/safefilepath/path_test.go | 88 +++++++++++++++++++++
+ src/internal/safefilepath/path_windows.go | 95 +++++++++++++++++++++++
+ src/net/http/fs.go | 8 +-
+ src/net/http/fs_test.go | 28 +++++++
+ src/os/file.go | 36 +++++++--
+ src/os/os_test.go | 38 +++++++++
+ 9 files changed, 328 insertions(+), 10 deletions(-)
+ create mode 100644 src/internal/safefilepath/path.go
+ create mode 100644 src/internal/safefilepath/path_other.go
+ create mode 100644 src/internal/safefilepath/path_test.go
+ create mode 100644 src/internal/safefilepath/path_windows.go
+
+diff --git a/src/go/build/deps_test.go b/src/go/build/deps_test.go
+index 45e2f25..dc3bb8c 100644
+--- a/src/go/build/deps_test.go
++++ b/src/go/build/deps_test.go
+@@ -165,6 +165,7 @@ var depsRules = `
+ io/fs
+ < internal/testlog
+ < internal/poll
++ < internal/safefilepath
+ < os
+ < os/signal;
+
+diff --git a/src/internal/safefilepath/path.go b/src/internal/safefilepath/path.go
+new file mode 100644
+index 0000000..0f0a270
+--- /dev/null
++++ b/src/internal/safefilepath/path.go
+@@ -0,0 +1,21 @@
++// Copyright 2022 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.
++
++// Package safefilepath manipulates operating-system file paths.
++package safefilepath
++
++import (
++ "errors"
++)
++
++var errInvalidPath = errors.New("invalid path")
++
++// FromFS converts a slash-separated path into an operating-system path.
++//
++// FromFS returns an error if the path cannot be represented by the operating
++// system. For example, paths containing '\' and ':' characters are rejected
++// on Windows.
++func FromFS(path string) (string, error) {
++ return fromFS(path)
++}
+diff --git a/src/internal/safefilepath/path_other.go b/src/internal/safefilepath/path_other.go
+new file mode 100644
+index 0000000..f93da18
+--- /dev/null
++++ b/src/internal/safefilepath/path_other.go
+@@ -0,0 +1,23 @@
++// Copyright 2022 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.
++
++//go:build !windows
++
++package safefilepath
++
++import "runtime"
++
++func fromFS(path string) (string, error) {
++ if runtime.GOOS == "plan9" {
++ if len(path) > 0 && path[0] == '#' {
++ return path, errInvalidPath
++ }
++ }
++ for i := range path {
++ if path[i] == 0 {
++ return "", errInvalidPath
++ }
++ }
++ return path, nil
++}
+diff --git a/src/internal/safefilepath/path_test.go b/src/internal/safefilepath/path_test.go
+new file mode 100644
+index 0000000..dc662c1
+--- /dev/null
++++ b/src/internal/safefilepath/path_test.go
+@@ -0,0 +1,88 @@
++// Copyright 2022 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.
++
++package safefilepath_test
++
++import (
++ "internal/safefilepath"
++ "os"
++ "path/filepath"
++ "runtime"
++ "testing"
++)
++
++type PathTest struct {
++ path, result string
++}
++
++const invalid = ""
++
++var fspathtests = []PathTest{
++ {".", "."},
++ {"/a/b/c", "/a/b/c"},
++ {"a\x00b", invalid},
++}
++
++var winreservedpathtests = []PathTest{
++ {`a\b`, `a\b`},
++ {`a:b`, `a:b`},
++ {`a/b:c`, `a/b:c`},
++ {`NUL`, `NUL`},
++ {`./com1`, `./com1`},
++ {`a/nul/b`, `a/nul/b`},
++}
++
++// Whether a reserved name with an extension is reserved or not varies by
++// Windows version.
++var winreservedextpathtests = []PathTest{
++ {"nul.txt", "nul.txt"},
++ {"a/nul.txt/b", "a/nul.txt/b"},
++}
++
++var plan9reservedpathtests = []PathTest{
++ {`#c`, `#c`},
++}
++
++func TestFromFS(t *testing.T) {
++ switch runtime.GOOS {
++ case "windows":
++ if canWriteFile(t, "NUL") {
++ t.Errorf("can unexpectedly write a file named NUL on Windows")
++ }
++ if canWriteFile(t, "nul.txt") {
++ fspathtests = append(fspathtests, winreservedextpathtests...)
++ } else {
++ winreservedpathtests = append(winreservedpathtests, winreservedextpathtests...)
++ }
++ for i := range winreservedpathtests {
++ winreservedpathtests[i].result = invalid
++ }
++ for i := range fspathtests {
++ fspathtests[i].result = filepath.FromSlash(fspathtests[i].result)
++ }
++ case "plan9":
++ for i := range plan9reservedpathtests {
++ plan9reservedpathtests[i].result = invalid
++ }
++ }
++ tests := fspathtests
++ tests = append(tests, winreservedpathtests...)
++ tests = append(tests, plan9reservedpathtests...)
++ for _, test := range tests {
++ got, err := safefilepath.FromFS(test.path)
++ if (got == "") != (err != nil) {
++ t.Errorf(`FromFS(%q) = %q, %v; want "" only if err != nil`, test.path, got, err)
++ }
++ if got != test.result {
++ t.Errorf("FromFS(%q) = %q, %v; want %q", test.path, got, err, test.result)
++ }
++ }
++}
++
++func canWriteFile(t *testing.T, name string) bool {
++ path := filepath.Join(t.TempDir(), name)
++ os.WriteFile(path, []byte("ok"), 0666)
++ b, _ := os.ReadFile(path)
++ return string(b) == "ok"
++}
+diff --git a/src/internal/safefilepath/path_windows.go b/src/internal/safefilepath/path_windows.go
+new file mode 100644
+index 0000000..909c150
+--- /dev/null
++++ b/src/internal/safefilepath/path_windows.go
+@@ -0,0 +1,95 @@
++// Copyright 2022 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.
++
++package safefilepath
++
++import (
++ "syscall"
++ "unicode/utf8"
++)
++
++func fromFS(path string) (string, error) {
++ if !utf8.ValidString(path) {
++ return "", errInvalidPath
++ }
++ for len(path) > 1 && path[0] == '/' && path[1] == '/' {
++ path = path[1:]
++ }
++ containsSlash := false
++ for p := path; p != ""; {
++ // Find the next path element.
++ i := 0
++ dot := -1
++ for i < len(p) && p[i] != '/' {
++ switch p[i] {
++ case 0, '\\', ':':
++ return "", errInvalidPath
++ case '.':
++ if dot < 0 {
++ dot = i
++ }
++ }
++ i++
++ }
++ part := p[:i]
++ if i < len(p) {
++ containsSlash = true
++ p = p[i+1:]
++ } else {
++ p = ""
++ }
++ // Trim the extension and look for a reserved name.
++ base := part
++ if dot >= 0 {
++ base = part[:dot]
++ }
++ if isReservedName(base) {
++ if dot < 0 {
++ return "", errInvalidPath
++ }
++ // The path element is a reserved name with an extension.
++ // Some Windows versions consider this a reserved name,
++ // while others do not. Use FullPath to see if the name is
++ // reserved.
++ if p, _ := syscall.FullPath(part); len(p) >= 4 && p[:4] == `\\.\` {
++ return "", errInvalidPath
++ }
++ }
++ }
++ if containsSlash {
++ // We can't depend on strings, so substitute \ for / manually.
++ buf := []byte(path)
++ for i, b := range buf {
++ if b == '/' {
++ buf[i] = '\\'
++ }
++ }
++ path = string(buf)
++ }
++ return path, nil
++}
++
++// isReservedName reports if name is a Windows reserved device name.
++// It does not detect names with an extension, which are also reserved on some Windows versions.
++//
++// For details, search for PRN in
++// https://docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file.
++func isReservedName(name string) bool {
++ if 3 <= len(name) && len(name) <= 4 {
++ switch string([]byte{toUpper(name[0]), toUpper(name[1]), toUpper(name[2])}) {
++ case "CON", "PRN", "AUX", "NUL":
++ return len(name) == 3
++ case "COM", "LPT":
++ return len(name) == 4 && '1' <= name[3] && name[3] <= '9'
++ }
++ }
++ return false
++}
++
++func toUpper(c byte) byte {
++ if 'a' <= c && c <= 'z' {
++ return c - ('a' - 'A')
++ }
++ return c
++}
+diff --git a/src/net/http/fs.go b/src/net/http/fs.go
+index 57e731e..43ee4b5 100644
+--- a/src/net/http/fs.go
++++ b/src/net/http/fs.go
+@@ -9,6 +9,7 @@ package http
+ import (
+ "errors"
+ "fmt"
++ "internal/safefilepath"
+ "io"
+ "io/fs"
+ "mime"
+@@ -69,14 +70,15 @@ func mapDirOpenError(originalErr error, name string) error {
+ // Open implements FileSystem using os.Open, opening files for reading rooted
+ // and relative to the directory d.
+ func (d Dir) Open(name string) (File, error) {
+- if filepath.Separator != '/' && strings.ContainsRune(name, filepath.Separator) {
+- return nil, errors.New("http: invalid character in file path")
++ path, err := safefilepath.FromFS(path.Clean("/" + name))
++ if err != nil {
++ return nil, errors.New("http: invalid or unsafe file path")
+ }
+ dir := string(d)
+ if dir == "" {
+ dir = "."
+ }
+- fullName := filepath.Join(dir, filepath.FromSlash(path.Clean("/"+name)))
++ fullName := filepath.Join(dir, path)
+ f, err := os.Open(fullName)
+ if err != nil {
+ return nil, mapDirOpenError(err, fullName)
+diff --git a/src/net/http/fs_test.go b/src/net/http/fs_test.go
+index b42ade1..941448a 100644
+--- a/src/net/http/fs_test.go
++++ b/src/net/http/fs_test.go
+@@ -648,6 +648,34 @@ func TestFileServerZeroByte(t *testing.T) {
+ }
+ }
+
++func TestFileServerNamesEscape(t *testing.T) {
++ t.Run("h1", func(t *testing.T) {
++ testFileServerNamesEscape(t, h1Mode)
++ })
++ t.Run("h2", func(t *testing.T) {
++ testFileServerNamesEscape(t, h2Mode)
++ })
++}
++func testFileServerNamesEscape(t *testing.T, h2 bool) {
++ defer afterTest(t)
++ ts := newClientServerTest(t, h2, FileServer(Dir("testdata"))).ts
++ defer ts.Close()
++ for _, path := range []string{
++ "/../testdata/file",
++ "/NUL", // don't read from device files on Windows
++ } {
++ res, err := ts.Client().Get(ts.URL + path)
++ if err != nil {
++ t.Fatal(err)
++ }
++ res.Body.Close()
++ if res.StatusCode < 400 || res.StatusCode > 599 {
++ t.Errorf("Get(%q): got status %v, want 4xx or 5xx", path, res.StatusCode)
++ }
++
++ }
++}
++
+ type fakeFileInfo struct {
+ dir bool
+ basename string
+diff --git a/src/os/file.go b/src/os/file.go
+index e717f17..cb87158 100644
+--- a/src/os/file.go
++++ b/src/os/file.go
+@@ -37,12 +37,12 @@
+ // Note: The maximum number of concurrent operations on a File may be limited by
+ // the OS or the system. The number should be high, but exceeding it may degrade
+ // performance or cause other issues.
+-//
+ package os
+
+ import (
+ "errors"
+ "internal/poll"
++ "internal/safefilepath"
+ "internal/testlog"
+ "internal/unsafeheader"
+ "io"
+@@ -623,6 +623,8 @@ func isWindowsNulName(name string) bool {
+ // the /prefix tree, then using DirFS does not stop the access any more than using
+ // os.Open does. DirFS is therefore not a general substitute for a chroot-style security
+ // mechanism when the directory tree contains arbitrary content.
++//
++// The directory dir must not be "".
+ func DirFS(dir string) fs.FS {
+ return dirFS(dir)
+ }
+@@ -641,10 +643,11 @@ func containsAny(s, chars string) bool {
+ type dirFS string
+
+ func (dir dirFS) Open(name string) (fs.File, error) {
+- if !fs.ValidPath(name) || runtime.GOOS == "windows" && containsAny(name, `\:`) {
+- return nil, &PathError{Op: "open", Path: name, Err: ErrInvalid}
++ fullname, err := dir.join(name)
++ if err != nil {
++ return nil, &PathError{Op: "stat", Path: name, Err: err}
+ }
+- f, err := Open(string(dir) + "/" + name)
++ f, err := Open(fullname)
+ if err != nil {
+ return nil, err // nil fs.File
+ }
+@@ -652,16 +655,35 @@ func (dir dirFS) Open(name string) (fs.File, error) {
+ }
+
+ func (dir dirFS) Stat(name string) (fs.FileInfo, error) {
+- if !fs.ValidPath(name) || runtime.GOOS == "windows" && containsAny(name, `\:`) {
+- return nil, &PathError{Op: "stat", Path: name, Err: ErrInvalid}
++ fullname, err := dir.join(name)
++ if err != nil {
++ return nil, &PathError{Op: "stat", Path: name, Err: err}
+ }
+- f, err := Stat(string(dir) + "/" + name)
++ f, err := Stat(fullname)
+ if err != nil {
+ return nil, err
+ }
+ return f, nil
+ }
+
++// join returns the path for name in dir.
++func (dir dirFS) join(name string) (string, error) {
++ if dir == "" {
++ return "", errors.New("os: DirFS with empty root")
++ }
++ if !fs.ValidPath(name) {
++ return "", ErrInvalid
++ }
++ name, err := safefilepath.FromFS(name)
++ if err != nil {
++ return "", ErrInvalid
++ }
++ if IsPathSeparator(dir[len(dir)-1]) {
++ return string(dir) + name, nil
++ }
++ return string(dir) + string(PathSeparator) + name, nil
++}
++
+ // ReadFile reads the named file and returns the contents.
+ // A successful call returns err == nil, not err == EOF.
+ // Because ReadFile reads the whole file, it does not treat an EOF from Read
+diff --git a/src/os/os_test.go b/src/os/os_test.go
+index 506f1fb..be269bb 100644
+--- a/src/os/os_test.go
++++ b/src/os/os_test.go
+@@ -2702,6 +2702,44 @@ func TestDirFS(t *testing.T) {
+ if err == nil {
+ t.Fatalf(`Open testdata\dirfs succeeded`)
+ }
++
++ // Test that Open does not open Windows device files.
++ _, err = d.Open(`NUL`)
++ if err == nil {
++ t.Errorf(`Open NUL succeeded`)
++ }
++}
++
++func TestDirFSRootDir(t *testing.T) {
++ cwd, err := os.Getwd()
++ if err != nil {
++ t.Fatal(err)
++ }
++ cwd = cwd[len(filepath.VolumeName(cwd)):] // trim volume prefix (C:) on Windows
++ cwd = filepath.ToSlash(cwd) // convert \ to /
++ cwd = strings.TrimPrefix(cwd, "/") // trim leading /
++
++ // Test that Open can open a path starting at /.
++ d := DirFS("/")
++ f, err := d.Open(cwd + "/testdata/dirfs/a")
++ if err != nil {
++ t.Fatal(err)
++ }
++ f.Close()
++}
++
++func TestDirFSEmptyDir(t *testing.T) {
++ d := DirFS("")
++ cwd, _ := os.Getwd()
++ for _, path := range []string{
++ "testdata/dirfs/a", // not DirFS(".")
++ filepath.ToSlash(cwd) + "/testdata/dirfs/a", // not DirFS("/")
++ } {
++ _, err := d.Open(path)
++ if err == nil {
++ t.Fatalf(`DirFS("").Open(%q) succeeded`, path)
++ }
++ }
+ }
+
+ func TestDirFSPathsValid(t *testing.T) {
--
2.40.0


Steve Sakoman
 

On Tue, Mar 21, 2023 at 9:36 AM Sakib Sajal <sakib.sajal@...> wrote:

Backport appropriate patches to fix CVE-2022-2879 and CVE-2022-41720.

Modified the original fix for CVE-2022-2879 to remove a testdata tarball
and any references to it since git binary diffs are not supported in
quilt.

Signed-off-by: Sakib Sajal <sakib.sajal@...>
---
meta/recipes-devtools/go/go-1.17.13.inc | 2 +
...01-archive-tar-limit-size-of-headers.patch | 177 ++++++
...d-escapes-from-os.DirFS-and-http.Dir.patch | 514 ++++++++++++++++++
3 files changed, 693 insertions(+)
create mode 100644 meta/recipes-devtools/go/go-1.18/0001-archive-tar-limit-size-of-headers.patch
create mode 100644 meta/recipes-devtools/go/go-1.18/0002-os-net-http-avoid-escapes-from-os.DirFS-and-http.Dir.patch

diff --git a/meta/recipes-devtools/go/go-1.17.13.inc b/meta/recipes-devtools/go/go-1.17.13.inc
index 99662bd298..a6081bdee7 100644
--- a/meta/recipes-devtools/go/go-1.17.13.inc
+++ b/meta/recipes-devtools/go/go-1.17.13.inc
@@ -20,6 +20,8 @@ SRC_URI += "\
file://0001-net-http-httputil-avoid-query-parameter-smuggling.patch \
file://CVE-2022-41715.patch \
file://CVE-2022-41717.patch \
+ file://0001-archive-tar-limit-size-of-headers.patch \
+ file://0002-os-net-http-avoid-escapes-from-os.DirFS-and-http.Dir.patch \
Could you please resubmit with the patch file names changed to reflect
the CVE they are fixing? i.e.

file://CVE-2022-2879.patch \
file://CVE-2022-41720.patch \

Thanks!

Steve

"
SRC_URI[main.sha256sum] = "a1a48b23afb206f95e7bbaa9b898d965f90826f6f1d1fc0c1d784ada0cd300fd"

diff --git a/meta/recipes-devtools/go/go-1.18/0001-archive-tar-limit-size-of-headers.patch b/meta/recipes-devtools/go/go-1.18/0001-archive-tar-limit-size-of-headers.patch
new file mode 100644
index 0000000000..0315e1a3ee
--- /dev/null
+++ b/meta/recipes-devtools/go/go-1.18/0001-archive-tar-limit-size-of-headers.patch
@@ -0,0 +1,177 @@
+From d064ed520a7cc6b480f9565e30751e695d394f4e Mon Sep 17 00:00:00 2001
+From: Damien Neil <dneil@...>
+Date: Fri, 2 Sep 2022 20:45:18 -0700
+Subject: [PATCH] archive/tar: limit size of headers
+
+Set a 1MiB limit on special file blocks (PAX headers, GNU long names,
+GNU link names), to avoid reading arbitrarily large amounts of data
+into memory.
+
+Thanks to Adam Korczynski (ADA Logics) and OSS-Fuzz for reporting
+this issue.
+
+Fixes CVE-2022-2879
+Updates #54853
+Fixes #55925
+
+Change-Id: I85136d6ff1e0af101a112190e027987ab4335680
+Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/1565555
+Reviewed-by: Tatiana Bradley <tatianabradley@...>
+Run-TryBot: Roland Shoemaker <bracewell@...>
+Reviewed-by: Roland Shoemaker <bracewell@...>
+(cherry picked from commit 6ee768cef6b82adf7a90dcf367a1699ef694f3b2)
+Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/1590622
+Reviewed-by: Damien Neil <dneil@...>
+Reviewed-by: Julie Qiu <julieqiu@...>
+Reviewed-on: https://go-review.googlesource.com/c/go/+/438500
+Reviewed-by: Dmitri Shuralyov <dmitshur@...>
+Reviewed-by: Carlos Amedee <carlos@...>
+Reviewed-by: Dmitri Shuralyov <dmitshur@...>
+Run-TryBot: Carlos Amedee <carlos@...>
+TryBot-Result: Gopher Robot <gobot@...>
+
+CVE: CVE-2022-2879
+Upstream-Status: Backport [0a723816cd205576945fa57fbdde7e6532d59d08]
+Signed-off-by: Sakib Sajal <sakib.sajal@...>
+---
+ src/archive/tar/format.go | 4 ++++
+ src/archive/tar/reader.go | 14 ++++++++++++--
+ src/archive/tar/reader_test.go | 8 +++++++-
+ src/archive/tar/writer.go | 3 +++
+ src/archive/tar/writer_test.go | 27 +++++++++++++++++++++++++++
+ 5 files changed, 53 insertions(+), 3 deletions(-)
+
+diff --git a/src/archive/tar/format.go b/src/archive/tar/format.go
+index cfe24a5..6642364 100644
+--- a/src/archive/tar/format.go
++++ b/src/archive/tar/format.go
+@@ -143,6 +143,10 @@ const (
+ blockSize = 512 // Size of each block in a tar stream
+ nameSize = 100 // Max length of the name field in USTAR format
+ prefixSize = 155 // Max length of the prefix field in USTAR format
++
++ // Max length of a special file (PAX header, GNU long name or link).
++ // This matches the limit used by libarchive.
++ maxSpecialFileSize = 1 << 20
+ )
+
+ // blockPadding computes the number of bytes needed to pad offset up to the
+diff --git a/src/archive/tar/reader.go b/src/archive/tar/reader.go
+index 1b1d5b4..f645af8 100644
+--- a/src/archive/tar/reader.go
++++ b/src/archive/tar/reader.go
+@@ -103,7 +103,7 @@ func (tr *Reader) next() (*Header, error) {
+ continue // This is a meta header affecting the next header
+ case TypeGNULongName, TypeGNULongLink:
+ format.mayOnlyBe(FormatGNU)
+- realname, err := io.ReadAll(tr)
++ realname, err := readSpecialFile(tr)
+ if err != nil {
+ return nil, err
+ }
+@@ -293,7 +293,7 @@ func mergePAX(hdr *Header, paxHdrs map[string]string) (err error) {
+ // parsePAX parses PAX headers.
+ // If an extended header (type 'x') is invalid, ErrHeader is returned
+ func parsePAX(r io.Reader) (map[string]string, error) {
+- buf, err := io.ReadAll(r)
++ buf, err := readSpecialFile(r)
+ if err != nil {
+ return nil, err
+ }
+@@ -826,6 +826,16 @@ func tryReadFull(r io.Reader, b []byte) (n int, err error) {
+ return n, err
+ }
+
++// readSpecialFile is like io.ReadAll except it returns
++// ErrFieldTooLong if more than maxSpecialFileSize is read.
++func readSpecialFile(r io.Reader) ([]byte, error) {
++ buf, err := io.ReadAll(io.LimitReader(r, maxSpecialFileSize+1))
++ if len(buf) > maxSpecialFileSize {
++ return nil, ErrFieldTooLong
++ }
++ return buf, err
++}
++
+ // discard skips n bytes in r, reporting an error if unable to do so.
+ func discard(r io.Reader, n int64) error {
+ // If possible, Seek to the last byte before the end of the data section.
+diff --git a/src/archive/tar/reader_test.go b/src/archive/tar/reader_test.go
+index 789ddc1..926dc3d 100644
+--- a/src/archive/tar/reader_test.go
++++ b/src/archive/tar/reader_test.go
+@@ -6,6 +6,7 @@ package tar
+
+ import (
+ "bytes"
++ "compress/bzip2"
+ "crypto/md5"
+ "errors"
+ "fmt"
+@@ -625,9 +626,14 @@ func TestReader(t *testing.T) {
+ }
+ defer f.Close()
+
++ var fr io.Reader = f
++ if strings.HasSuffix(v.file, ".bz2") {
++ fr = bzip2.NewReader(fr)
++ }
++
+ // Capture all headers and checksums.
+ var (
+- tr = NewReader(f)
++ tr = NewReader(fr)
+ hdrs []*Header
+ chksums []string
+ rdbuf = make([]byte, 8)
+diff --git a/src/archive/tar/writer.go b/src/archive/tar/writer.go
+index e80498d..893eac0 100644
+--- a/src/archive/tar/writer.go
++++ b/src/archive/tar/writer.go
+@@ -199,6 +199,9 @@ func (tw *Writer) writePAXHeader(hdr *Header, paxHdrs map[string]string) error {
+ flag = TypeXHeader
+ }
+ data := buf.String()
++ if len(data) > maxSpecialFileSize {
++ return ErrFieldTooLong
++ }
+ if err := tw.writeRawFile(name, data, flag, FormatPAX); err != nil || isGlobal {
+ return err // Global headers return here
+ }
+diff --git a/src/archive/tar/writer_test.go b/src/archive/tar/writer_test.go
+index a00f02d..4e709e5 100644
+--- a/src/archive/tar/writer_test.go
++++ b/src/archive/tar/writer_test.go
+@@ -1006,6 +1006,33 @@ func TestIssue12594(t *testing.T) {
+ }
+ }
+
++func TestWriteLongHeader(t *testing.T) {
++ for _, test := range []struct {
++ name string
++ h *Header
++ }{{
++ name: "name too long",
++ h: &Header{Name: strings.Repeat("a", maxSpecialFileSize)},
++ }, {
++ name: "linkname too long",
++ h: &Header{Linkname: strings.Repeat("a", maxSpecialFileSize)},
++ }, {
++ name: "uname too long",
++ h: &Header{Uname: strings.Repeat("a", maxSpecialFileSize)},
++ }, {
++ name: "gname too long",
++ h: &Header{Gname: strings.Repeat("a", maxSpecialFileSize)},
++ }, {
++ name: "PAX header too long",
++ h: &Header{PAXRecords: map[string]string{"GOLANG.x": strings.Repeat("a", maxSpecialFileSize)}},
++ }} {
++ w := NewWriter(io.Discard)
++ if err := w.WriteHeader(test.h); err != ErrFieldTooLong {
++ t.Errorf("%v: w.WriteHeader() = %v, want ErrFieldTooLong", test.name, err)
++ }
++ }
++}
++
+ // testNonEmptyWriter wraps an io.Writer and ensures that
+ // Write is never called with an empty buffer.
+ type testNonEmptyWriter struct{ io.Writer }
diff --git a/meta/recipes-devtools/go/go-1.18/0002-os-net-http-avoid-escapes-from-os.DirFS-and-http.Dir.patch b/meta/recipes-devtools/go/go-1.18/0002-os-net-http-avoid-escapes-from-os.DirFS-and-http.Dir.patch
new file mode 100644
index 0000000000..6c2e8804b3
--- /dev/null
+++ b/meta/recipes-devtools/go/go-1.18/0002-os-net-http-avoid-escapes-from-os.DirFS-and-http.Dir.patch
@@ -0,0 +1,514 @@
+From f8896a97a0630b0f2f8c488310147f7f20b3ec7d Mon Sep 17 00:00:00 2001
+From: Damien Neil <dneil@...>
+Date: Thu, 10 Nov 2022 12:16:27 -0800
+Subject: [PATCH] os, net/http: avoid escapes from os.DirFS and http.Dir on
+ Windows
+
+Do not permit access to Windows reserved device names (NUL, COM1, etc.)
+via os.DirFS and http.Dir filesystems.
+
+Avoid escapes from os.DirFS(`\`) on Windows. DirFS would join the
+the root to the relative path with a path separator, making
+os.DirFS(`\`).Open(`/foo/bar`) open the path `\\foo\bar`, which is
+a UNC name. Not only does this not open the intended file, but permits
+reference to any file on the system rather than only files on the
+current drive.
+
+Make os.DirFS("") invalid, with all file access failing. Previously,
+a root of "" was interpreted as "/", which is surprising and probably
+unintentional.
+
+Fixes CVE-2022-41720.
+Fixes #56694.
+
+Change-Id: I275b5fa391e6ad7404309ea98ccc97405942e0f0
+Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/1663832
+Reviewed-by: Julie Qiu <julieqiu@...>
+Reviewed-by: Tatiana Bradley <tatianabradley@...>
+Reviewed-on: https://go-review.googlesource.com/c/go/+/455360
+Reviewed-by: Michael Pratt <mpratt@...>
+TryBot-Result: Gopher Robot <gobot@...>
+Run-TryBot: Jenny Rakoczy <jenny@...>
+
+CVE: CVE-2022-41720
+Upstream-Status: Backport [7013a4f5f816af62033ad63dd06b77c30d7a62a7]
+Signed-off-by: Sakib Sajal <sakib.sajal@...>
+---
+ src/go/build/deps_test.go | 1 +
+ src/internal/safefilepath/path.go | 21 +++++
+ src/internal/safefilepath/path_other.go | 23 ++++++
+ src/internal/safefilepath/path_test.go | 88 +++++++++++++++++++++
+ src/internal/safefilepath/path_windows.go | 95 +++++++++++++++++++++++
+ src/net/http/fs.go | 8 +-
+ src/net/http/fs_test.go | 28 +++++++
+ src/os/file.go | 36 +++++++--
+ src/os/os_test.go | 38 +++++++++
+ 9 files changed, 328 insertions(+), 10 deletions(-)
+ create mode 100644 src/internal/safefilepath/path.go
+ create mode 100644 src/internal/safefilepath/path_other.go
+ create mode 100644 src/internal/safefilepath/path_test.go
+ create mode 100644 src/internal/safefilepath/path_windows.go
+
+diff --git a/src/go/build/deps_test.go b/src/go/build/deps_test.go
+index 45e2f25..dc3bb8c 100644
+--- a/src/go/build/deps_test.go
++++ b/src/go/build/deps_test.go
+@@ -165,6 +165,7 @@ var depsRules = `
+ io/fs
+ < internal/testlog
+ < internal/poll
++ < internal/safefilepath
+ < os
+ < os/signal;
+
+diff --git a/src/internal/safefilepath/path.go b/src/internal/safefilepath/path.go
+new file mode 100644
+index 0000000..0f0a270
+--- /dev/null
++++ b/src/internal/safefilepath/path.go
+@@ -0,0 +1,21 @@
++// Copyright 2022 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.
++
++// Package safefilepath manipulates operating-system file paths.
++package safefilepath
++
++import (
++ "errors"
++)
++
++var errInvalidPath = errors.New("invalid path")
++
++// FromFS converts a slash-separated path into an operating-system path.
++//
++// FromFS returns an error if the path cannot be represented by the operating
++// system. For example, paths containing '\' and ':' characters are rejected
++// on Windows.
++func FromFS(path string) (string, error) {
++ return fromFS(path)
++}
+diff --git a/src/internal/safefilepath/path_other.go b/src/internal/safefilepath/path_other.go
+new file mode 100644
+index 0000000..f93da18
+--- /dev/null
++++ b/src/internal/safefilepath/path_other.go
+@@ -0,0 +1,23 @@
++// Copyright 2022 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.
++
++//go:build !windows
++
++package safefilepath
++
++import "runtime"
++
++func fromFS(path string) (string, error) {
++ if runtime.GOOS == "plan9" {
++ if len(path) > 0 && path[0] == '#' {
++ return path, errInvalidPath
++ }
++ }
++ for i := range path {
++ if path[i] == 0 {
++ return "", errInvalidPath
++ }
++ }
++ return path, nil
++}
+diff --git a/src/internal/safefilepath/path_test.go b/src/internal/safefilepath/path_test.go
+new file mode 100644
+index 0000000..dc662c1
+--- /dev/null
++++ b/src/internal/safefilepath/path_test.go
+@@ -0,0 +1,88 @@
++// Copyright 2022 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.
++
++package safefilepath_test
++
++import (
++ "internal/safefilepath"
++ "os"
++ "path/filepath"
++ "runtime"
++ "testing"
++)
++
++type PathTest struct {
++ path, result string
++}
++
++const invalid = ""
++
++var fspathtests = []PathTest{
++ {".", "."},
++ {"/a/b/c", "/a/b/c"},
++ {"a\x00b", invalid},
++}
++
++var winreservedpathtests = []PathTest{
++ {`a\b`, `a\b`},
++ {`a:b`, `a:b`},
++ {`a/b:c`, `a/b:c`},
++ {`NUL`, `NUL`},
++ {`./com1`, `./com1`},
++ {`a/nul/b`, `a/nul/b`},
++}
++
++// Whether a reserved name with an extension is reserved or not varies by
++// Windows version.
++var winreservedextpathtests = []PathTest{
++ {"nul.txt", "nul.txt"},
++ {"a/nul.txt/b", "a/nul.txt/b"},
++}
++
++var plan9reservedpathtests = []PathTest{
++ {`#c`, `#c`},
++}
++
++func TestFromFS(t *testing.T) {
++ switch runtime.GOOS {
++ case "windows":
++ if canWriteFile(t, "NUL") {
++ t.Errorf("can unexpectedly write a file named NUL on Windows")
++ }
++ if canWriteFile(t, "nul.txt") {
++ fspathtests = append(fspathtests, winreservedextpathtests...)
++ } else {
++ winreservedpathtests = append(winreservedpathtests, winreservedextpathtests...)
++ }
++ for i := range winreservedpathtests {
++ winreservedpathtests[i].result = invalid
++ }
++ for i := range fspathtests {
++ fspathtests[i].result = filepath.FromSlash(fspathtests[i].result)
++ }
++ case "plan9":
++ for i := range plan9reservedpathtests {
++ plan9reservedpathtests[i].result = invalid
++ }
++ }
++ tests := fspathtests
++ tests = append(tests, winreservedpathtests...)
++ tests = append(tests, plan9reservedpathtests...)
++ for _, test := range tests {
++ got, err := safefilepath.FromFS(test.path)
++ if (got == "") != (err != nil) {
++ t.Errorf(`FromFS(%q) = %q, %v; want "" only if err != nil`, test.path, got, err)
++ }
++ if got != test.result {
++ t.Errorf("FromFS(%q) = %q, %v; want %q", test.path, got, err, test.result)
++ }
++ }
++}
++
++func canWriteFile(t *testing.T, name string) bool {
++ path := filepath.Join(t.TempDir(), name)
++ os.WriteFile(path, []byte("ok"), 0666)
++ b, _ := os.ReadFile(path)
++ return string(b) == "ok"
++}
+diff --git a/src/internal/safefilepath/path_windows.go b/src/internal/safefilepath/path_windows.go
+new file mode 100644
+index 0000000..909c150
+--- /dev/null
++++ b/src/internal/safefilepath/path_windows.go
+@@ -0,0 +1,95 @@
++// Copyright 2022 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.
++
++package safefilepath
++
++import (
++ "syscall"
++ "unicode/utf8"
++)
++
++func fromFS(path string) (string, error) {
++ if !utf8.ValidString(path) {
++ return "", errInvalidPath
++ }
++ for len(path) > 1 && path[0] == '/' && path[1] == '/' {
++ path = path[1:]
++ }
++ containsSlash := false
++ for p := path; p != ""; {
++ // Find the next path element.
++ i := 0
++ dot := -1
++ for i < len(p) && p[i] != '/' {
++ switch p[i] {
++ case 0, '\\', ':':
++ return "", errInvalidPath
++ case '.':
++ if dot < 0 {
++ dot = i
++ }
++ }
++ i++
++ }
++ part := p[:i]
++ if i < len(p) {
++ containsSlash = true
++ p = p[i+1:]
++ } else {
++ p = ""
++ }
++ // Trim the extension and look for a reserved name.
++ base := part
++ if dot >= 0 {
++ base = part[:dot]
++ }
++ if isReservedName(base) {
++ if dot < 0 {
++ return "", errInvalidPath
++ }
++ // The path element is a reserved name with an extension.
++ // Some Windows versions consider this a reserved name,
++ // while others do not. Use FullPath to see if the name is
++ // reserved.
++ if p, _ := syscall.FullPath(part); len(p) >= 4 && p[:4] == `\\.\` {
++ return "", errInvalidPath
++ }
++ }
++ }
++ if containsSlash {
++ // We can't depend on strings, so substitute \ for / manually.
++ buf := []byte(path)
++ for i, b := range buf {
++ if b == '/' {
++ buf[i] = '\\'
++ }
++ }
++ path = string(buf)
++ }
++ return path, nil
++}
++
++// isReservedName reports if name is a Windows reserved device name.
++// It does not detect names with an extension, which are also reserved on some Windows versions.
++//
++// For details, search for PRN in
++// https://docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file.
++func isReservedName(name string) bool {
++ if 3 <= len(name) && len(name) <= 4 {
++ switch string([]byte{toUpper(name[0]), toUpper(name[1]), toUpper(name[2])}) {
++ case "CON", "PRN", "AUX", "NUL":
++ return len(name) == 3
++ case "COM", "LPT":
++ return len(name) == 4 && '1' <= name[3] && name[3] <= '9'
++ }
++ }
++ return false
++}
++
++func toUpper(c byte) byte {
++ if 'a' <= c && c <= 'z' {
++ return c - ('a' - 'A')
++ }
++ return c
++}
+diff --git a/src/net/http/fs.go b/src/net/http/fs.go
+index 57e731e..43ee4b5 100644
+--- a/src/net/http/fs.go
++++ b/src/net/http/fs.go
+@@ -9,6 +9,7 @@ package http
+ import (
+ "errors"
+ "fmt"
++ "internal/safefilepath"
+ "io"
+ "io/fs"
+ "mime"
+@@ -69,14 +70,15 @@ func mapDirOpenError(originalErr error, name string) error {
+ // Open implements FileSystem using os.Open, opening files for reading rooted
+ // and relative to the directory d.
+ func (d Dir) Open(name string) (File, error) {
+- if filepath.Separator != '/' && strings.ContainsRune(name, filepath.Separator) {
+- return nil, errors.New("http: invalid character in file path")
++ path, err := safefilepath.FromFS(path.Clean("/" + name))
++ if err != nil {
++ return nil, errors.New("http: invalid or unsafe file path")
+ }
+ dir := string(d)
+ if dir == "" {
+ dir = "."
+ }
+- fullName := filepath.Join(dir, filepath.FromSlash(path.Clean("/"+name)))
++ fullName := filepath.Join(dir, path)
+ f, err := os.Open(fullName)
+ if err != nil {
+ return nil, mapDirOpenError(err, fullName)
+diff --git a/src/net/http/fs_test.go b/src/net/http/fs_test.go
+index b42ade1..941448a 100644
+--- a/src/net/http/fs_test.go
++++ b/src/net/http/fs_test.go
+@@ -648,6 +648,34 @@ func TestFileServerZeroByte(t *testing.T) {
+ }
+ }
+
++func TestFileServerNamesEscape(t *testing.T) {
++ t.Run("h1", func(t *testing.T) {
++ testFileServerNamesEscape(t, h1Mode)
++ })
++ t.Run("h2", func(t *testing.T) {
++ testFileServerNamesEscape(t, h2Mode)
++ })
++}
++func testFileServerNamesEscape(t *testing.T, h2 bool) {
++ defer afterTest(t)
++ ts := newClientServerTest(t, h2, FileServer(Dir("testdata"))).ts
++ defer ts.Close()
++ for _, path := range []string{
++ "/../testdata/file",
++ "/NUL", // don't read from device files on Windows
++ } {
++ res, err := ts.Client().Get(ts.URL + path)
++ if err != nil {
++ t.Fatal(err)
++ }
++ res.Body.Close()
++ if res.StatusCode < 400 || res.StatusCode > 599 {
++ t.Errorf("Get(%q): got status %v, want 4xx or 5xx", path, res.StatusCode)
++ }
++
++ }
++}
++
+ type fakeFileInfo struct {
+ dir bool
+ basename string
+diff --git a/src/os/file.go b/src/os/file.go
+index e717f17..cb87158 100644
+--- a/src/os/file.go
++++ b/src/os/file.go
+@@ -37,12 +37,12 @@
+ // Note: The maximum number of concurrent operations on a File may be limited by
+ // the OS or the system. The number should be high, but exceeding it may degrade
+ // performance or cause other issues.
+-//
+ package os
+
+ import (
+ "errors"
+ "internal/poll"
++ "internal/safefilepath"
+ "internal/testlog"
+ "internal/unsafeheader"
+ "io"
+@@ -623,6 +623,8 @@ func isWindowsNulName(name string) bool {
+ // the /prefix tree, then using DirFS does not stop the access any more than using
+ // os.Open does. DirFS is therefore not a general substitute for a chroot-style security
+ // mechanism when the directory tree contains arbitrary content.
++//
++// The directory dir must not be "".
+ func DirFS(dir string) fs.FS {
+ return dirFS(dir)
+ }
+@@ -641,10 +643,11 @@ func containsAny(s, chars string) bool {
+ type dirFS string
+
+ func (dir dirFS) Open(name string) (fs.File, error) {
+- if !fs.ValidPath(name) || runtime.GOOS == "windows" && containsAny(name, `\:`) {
+- return nil, &PathError{Op: "open", Path: name, Err: ErrInvalid}
++ fullname, err := dir.join(name)
++ if err != nil {
++ return nil, &PathError{Op: "stat", Path: name, Err: err}
+ }
+- f, err := Open(string(dir) + "/" + name)
++ f, err := Open(fullname)
+ if err != nil {
+ return nil, err // nil fs.File
+ }
+@@ -652,16 +655,35 @@ func (dir dirFS) Open(name string) (fs.File, error) {
+ }
+
+ func (dir dirFS) Stat(name string) (fs.FileInfo, error) {
+- if !fs.ValidPath(name) || runtime.GOOS == "windows" && containsAny(name, `\:`) {
+- return nil, &PathError{Op: "stat", Path: name, Err: ErrInvalid}
++ fullname, err := dir.join(name)
++ if err != nil {
++ return nil, &PathError{Op: "stat", Path: name, Err: err}
+ }
+- f, err := Stat(string(dir) + "/" + name)
++ f, err := Stat(fullname)
+ if err != nil {
+ return nil, err
+ }
+ return f, nil
+ }
+
++// join returns the path for name in dir.
++func (dir dirFS) join(name string) (string, error) {
++ if dir == "" {
++ return "", errors.New("os: DirFS with empty root")
++ }
++ if !fs.ValidPath(name) {
++ return "", ErrInvalid
++ }
++ name, err := safefilepath.FromFS(name)
++ if err != nil {
++ return "", ErrInvalid
++ }
++ if IsPathSeparator(dir[len(dir)-1]) {
++ return string(dir) + name, nil
++ }
++ return string(dir) + string(PathSeparator) + name, nil
++}
++
+ // ReadFile reads the named file and returns the contents.
+ // A successful call returns err == nil, not err == EOF.
+ // Because ReadFile reads the whole file, it does not treat an EOF from Read
+diff --git a/src/os/os_test.go b/src/os/os_test.go
+index 506f1fb..be269bb 100644
+--- a/src/os/os_test.go
++++ b/src/os/os_test.go
+@@ -2702,6 +2702,44 @@ func TestDirFS(t *testing.T) {
+ if err == nil {
+ t.Fatalf(`Open testdata\dirfs succeeded`)
+ }
++
++ // Test that Open does not open Windows device files.
++ _, err = d.Open(`NUL`)
++ if err == nil {
++ t.Errorf(`Open NUL succeeded`)
++ }
++}
++
++func TestDirFSRootDir(t *testing.T) {
++ cwd, err := os.Getwd()
++ if err != nil {
++ t.Fatal(err)
++ }
++ cwd = cwd[len(filepath.VolumeName(cwd)):] // trim volume prefix (C:) on Windows
++ cwd = filepath.ToSlash(cwd) // convert \ to /
++ cwd = strings.TrimPrefix(cwd, "/") // trim leading /
++
++ // Test that Open can open a path starting at /.
++ d := DirFS("/")
++ f, err := d.Open(cwd + "/testdata/dirfs/a")
++ if err != nil {
++ t.Fatal(err)
++ }
++ f.Close()
++}
++
++func TestDirFSEmptyDir(t *testing.T) {
++ d := DirFS("")
++ cwd, _ := os.Getwd()
++ for _, path := range []string{
++ "testdata/dirfs/a", // not DirFS(".")
++ filepath.ToSlash(cwd) + "/testdata/dirfs/a", // not DirFS("/")
++ } {
++ _, err := d.Open(path)
++ if err == nil {
++ t.Fatalf(`DirFS("").Open(%q) succeeded`, path)
++ }
++ }
+ }
+
+ func TestDirFSPathsValid(t *testing.T) {
--
2.40.0




Sakib Sajal
 

On 2023-03-22 12:21, Steve Sakoman wrote:
CAUTION: This email comes from a non Wind River email account!
Do not click links or open attachments unless you recognize the sender and know the content is safe.

On Tue, Mar 21, 2023 at 9:36 AM Sakib Sajal <sakib.sajal@...> wrote:
Backport appropriate patches to fix CVE-2022-2879 and CVE-2022-41720.

Modified the original fix for CVE-2022-2879 to remove a testdata tarball
and any references to it since git binary diffs are not supported in
quilt.

Signed-off-by: Sakib Sajal <sakib.sajal@...>
---
meta/recipes-devtools/go/go-1.17.13.inc | 2 +
...01-archive-tar-limit-size-of-headers.patch | 177 ++++++
...d-escapes-from-os.DirFS-and-http.Dir.patch | 514 ++++++++++++++++++
3 files changed, 693 insertions(+)
create mode 100644 meta/recipes-devtools/go/go-1.18/0001-archive-tar-limit-size-of-headers.patch
create mode 100644 meta/recipes-devtools/go/go-1.18/0002-os-net-http-avoid-escapes-from-os.DirFS-and-http.Dir.patch

diff --git a/meta/recipes-devtools/go/go-1.17.13.inc b/meta/recipes-devtools/go/go-1.17.13.inc
index 99662bd298..a6081bdee7 100644
--- a/meta/recipes-devtools/go/go-1.17.13.inc
+++ b/meta/recipes-devtools/go/go-1.17.13.inc
@@ -20,6 +20,8 @@ SRC_URI += "\
file://0001-net-http-httputil-avoid-query-parameter-smuggling.patch \
file://CVE-2022-41715.patch \
file://CVE-2022-41717.patch \
+ file://0001-archive-tar-limit-size-of-headers.patch \
+ file://0002-os-net-http-avoid-escapes-from-os.DirFS-and-http.Dir.patch \
Could you please resubmit with the patch file names changed to reflect
the CVE they are fixing? i.e.

file://CVE-2022-2879.patch \
file://CVE-2022-41720.patch \

Thanks!

Steve
Done!

Sakib


"
SRC_URI[main.sha256sum] = "a1a48b23afb206f95e7bbaa9b898d965f90826f6f1d1fc0c1d784ada0cd300fd"

diff --git a/meta/recipes-devtools/go/go-1.18/0001-archive-tar-limit-size-of-headers.patch b/meta/recipes-devtools/go/go-1.18/0001-archive-tar-limit-size-of-headers.patch
new file mode 100644
index 0000000000..0315e1a3ee
--- /dev/null
+++ b/meta/recipes-devtools/go/go-1.18/0001-archive-tar-limit-size-of-headers.patch
@@ -0,0 +1,177 @@
+From d064ed520a7cc6b480f9565e30751e695d394f4e Mon Sep 17 00:00:00 2001
+From: Damien Neil <dneil@...>
+Date: Fri, 2 Sep 2022 20:45:18 -0700
+Subject: [PATCH] archive/tar: limit size of headers
+
+Set a 1MiB limit on special file blocks (PAX headers, GNU long names,
+GNU link names), to avoid reading arbitrarily large amounts of data
+into memory.
+
+Thanks to Adam Korczynski (ADA Logics) and OSS-Fuzz for reporting
+this issue.
+
+Fixes CVE-2022-2879
+Updates #54853
+Fixes #55925
+
+Change-Id: I85136d6ff1e0af101a112190e027987ab4335680
+Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/1565555
+Reviewed-by: Tatiana Bradley <tatianabradley@...>
+Run-TryBot: Roland Shoemaker <bracewell@...>
+Reviewed-by: Roland Shoemaker <bracewell@...>
+(cherry picked from commit 6ee768cef6b82adf7a90dcf367a1699ef694f3b2)
+Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/1590622
+Reviewed-by: Damien Neil <dneil@...>
+Reviewed-by: Julie Qiu <julieqiu@...>
+Reviewed-on: https://go-review.googlesource.com/c/go/+/438500
+Reviewed-by: Dmitri Shuralyov <dmitshur@...>
+Reviewed-by: Carlos Amedee <carlos@...>
+Reviewed-by: Dmitri Shuralyov <dmitshur@...>
+Run-TryBot: Carlos Amedee <carlos@...>
+TryBot-Result: Gopher Robot <gobot@...>
+
+CVE: CVE-2022-2879
+Upstream-Status: Backport [0a723816cd205576945fa57fbdde7e6532d59d08]
+Signed-off-by: Sakib Sajal <sakib.sajal@...>
+---
+ src/archive/tar/format.go | 4 ++++
+ src/archive/tar/reader.go | 14 ++++++++++++--
+ src/archive/tar/reader_test.go | 8 +++++++-
+ src/archive/tar/writer.go | 3 +++
+ src/archive/tar/writer_test.go | 27 +++++++++++++++++++++++++++
+ 5 files changed, 53 insertions(+), 3 deletions(-)
+
+diff --git a/src/archive/tar/format.go b/src/archive/tar/format.go
+index cfe24a5..6642364 100644
+--- a/src/archive/tar/format.go
++++ b/src/archive/tar/format.go
+@@ -143,6 +143,10 @@ const (
+ blockSize = 512 // Size of each block in a tar stream
+ nameSize = 100 // Max length of the name field in USTAR format
+ prefixSize = 155 // Max length of the prefix field in USTAR format
++
++ // Max length of a special file (PAX header, GNU long name or link).
++ // This matches the limit used by libarchive.
++ maxSpecialFileSize = 1 << 20
+ )
+
+ // blockPadding computes the number of bytes needed to pad offset up to the
+diff --git a/src/archive/tar/reader.go b/src/archive/tar/reader.go
+index 1b1d5b4..f645af8 100644
+--- a/src/archive/tar/reader.go
++++ b/src/archive/tar/reader.go
+@@ -103,7 +103,7 @@ func (tr *Reader) next() (*Header, error) {
+ continue // This is a meta header affecting the next header
+ case TypeGNULongName, TypeGNULongLink:
+ format.mayOnlyBe(FormatGNU)
+- realname, err := io.ReadAll(tr)
++ realname, err := readSpecialFile(tr)
+ if err != nil {
+ return nil, err
+ }
+@@ -293,7 +293,7 @@ func mergePAX(hdr *Header, paxHdrs map[string]string) (err error) {
+ // parsePAX parses PAX headers.
+ // If an extended header (type 'x') is invalid, ErrHeader is returned
+ func parsePAX(r io.Reader) (map[string]string, error) {
+- buf, err := io.ReadAll(r)
++ buf, err := readSpecialFile(r)
+ if err != nil {
+ return nil, err
+ }
+@@ -826,6 +826,16 @@ func tryReadFull(r io.Reader, b []byte) (n int, err error) {
+ return n, err
+ }
+
++// readSpecialFile is like io.ReadAll except it returns
++// ErrFieldTooLong if more than maxSpecialFileSize is read.
++func readSpecialFile(r io.Reader) ([]byte, error) {
++ buf, err := io.ReadAll(io.LimitReader(r, maxSpecialFileSize+1))
++ if len(buf) > maxSpecialFileSize {
++ return nil, ErrFieldTooLong
++ }
++ return buf, err
++}
++
+ // discard skips n bytes in r, reporting an error if unable to do so.
+ func discard(r io.Reader, n int64) error {
+ // If possible, Seek to the last byte before the end of the data section.
+diff --git a/src/archive/tar/reader_test.go b/src/archive/tar/reader_test.go
+index 789ddc1..926dc3d 100644
+--- a/src/archive/tar/reader_test.go
++++ b/src/archive/tar/reader_test.go
+@@ -6,6 +6,7 @@ package tar
+
+ import (
+ "bytes"
++ "compress/bzip2"
+ "crypto/md5"
+ "errors"
+ "fmt"
+@@ -625,9 +626,14 @@ func TestReader(t *testing.T) {
+ }
+ defer f.Close()
+
++ var fr io.Reader = f
++ if strings.HasSuffix(v.file, ".bz2") {
++ fr = bzip2.NewReader(fr)
++ }
++
+ // Capture all headers and checksums.
+ var (
+- tr = NewReader(f)
++ tr = NewReader(fr)
+ hdrs []*Header
+ chksums []string
+ rdbuf = make([]byte, 8)
+diff --git a/src/archive/tar/writer.go b/src/archive/tar/writer.go
+index e80498d..893eac0 100644
+--- a/src/archive/tar/writer.go
++++ b/src/archive/tar/writer.go
+@@ -199,6 +199,9 @@ func (tw *Writer) writePAXHeader(hdr *Header, paxHdrs map[string]string) error {
+ flag = TypeXHeader
+ }
+ data := buf.String()
++ if len(data) > maxSpecialFileSize {
++ return ErrFieldTooLong
++ }
+ if err := tw.writeRawFile(name, data, flag, FormatPAX); err != nil || isGlobal {
+ return err // Global headers return here
+ }
+diff --git a/src/archive/tar/writer_test.go b/src/archive/tar/writer_test.go
+index a00f02d..4e709e5 100644
+--- a/src/archive/tar/writer_test.go
++++ b/src/archive/tar/writer_test.go
+@@ -1006,6 +1006,33 @@ func TestIssue12594(t *testing.T) {
+ }
+ }
+
++func TestWriteLongHeader(t *testing.T) {
++ for _, test := range []struct {
++ name string
++ h *Header
++ }{{
++ name: "name too long",
++ h: &Header{Name: strings.Repeat("a", maxSpecialFileSize)},
++ }, {
++ name: "linkname too long",
++ h: &Header{Linkname: strings.Repeat("a", maxSpecialFileSize)},
++ }, {
++ name: "uname too long",
++ h: &Header{Uname: strings.Repeat("a", maxSpecialFileSize)},
++ }, {
++ name: "gname too long",
++ h: &Header{Gname: strings.Repeat("a", maxSpecialFileSize)},
++ }, {
++ name: "PAX header too long",
++ h: &Header{PAXRecords: map[string]string{"GOLANG.x": strings.Repeat("a", maxSpecialFileSize)}},
++ }} {
++ w := NewWriter(io.Discard)
++ if err := w.WriteHeader(test.h); err != ErrFieldTooLong {
++ t.Errorf("%v: w.WriteHeader() = %v, want ErrFieldTooLong", test.name, err)
++ }
++ }
++}
++
+ // testNonEmptyWriter wraps an io.Writer and ensures that
+ // Write is never called with an empty buffer.
+ type testNonEmptyWriter struct{ io.Writer }
diff --git a/meta/recipes-devtools/go/go-1.18/0002-os-net-http-avoid-escapes-from-os.DirFS-and-http.Dir.patch b/meta/recipes-devtools/go/go-1.18/0002-os-net-http-avoid-escapes-from-os.DirFS-and-http.Dir.patch
new file mode 100644
index 0000000000..6c2e8804b3
--- /dev/null
+++ b/meta/recipes-devtools/go/go-1.18/0002-os-net-http-avoid-escapes-from-os.DirFS-and-http.Dir.patch
@@ -0,0 +1,514 @@
+From f8896a97a0630b0f2f8c488310147f7f20b3ec7d Mon Sep 17 00:00:00 2001
+From: Damien Neil <dneil@...>
+Date: Thu, 10 Nov 2022 12:16:27 -0800
+Subject: [PATCH] os, net/http: avoid escapes from os.DirFS and http.Dir on
+ Windows
+
+Do not permit access to Windows reserved device names (NUL, COM1, etc.)
+via os.DirFS and http.Dir filesystems.
+
+Avoid escapes from os.DirFS(`\`) on Windows. DirFS would join the
+the root to the relative path with a path separator, making
+os.DirFS(`\`).Open(`/foo/bar`) open the path `\\foo\bar`, which is
+a UNC name. Not only does this not open the intended file, but permits
+reference to any file on the system rather than only files on the
+current drive.
+
+Make os.DirFS("") invalid, with all file access failing. Previously,
+a root of "" was interpreted as "/", which is surprising and probably
+unintentional.
+
+Fixes CVE-2022-41720.
+Fixes #56694.
+
+Change-Id: I275b5fa391e6ad7404309ea98ccc97405942e0f0
+Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/1663832
+Reviewed-by: Julie Qiu <julieqiu@...>
+Reviewed-by: Tatiana Bradley <tatianabradley@...>
+Reviewed-on: https://go-review.googlesource.com/c/go/+/455360
+Reviewed-by: Michael Pratt <mpratt@...>
+TryBot-Result: Gopher Robot <gobot@...>
+Run-TryBot: Jenny Rakoczy <jenny@...>
+
+CVE: CVE-2022-41720
+Upstream-Status: Backport [7013a4f5f816af62033ad63dd06b77c30d7a62a7]
+Signed-off-by: Sakib Sajal <sakib.sajal@...>
+---
+ src/go/build/deps_test.go | 1 +
+ src/internal/safefilepath/path.go | 21 +++++
+ src/internal/safefilepath/path_other.go | 23 ++++++
+ src/internal/safefilepath/path_test.go | 88 +++++++++++++++++++++
+ src/internal/safefilepath/path_windows.go | 95 +++++++++++++++++++++++
+ src/net/http/fs.go | 8 +-
+ src/net/http/fs_test.go | 28 +++++++
+ src/os/file.go | 36 +++++++--
+ src/os/os_test.go | 38 +++++++++
+ 9 files changed, 328 insertions(+), 10 deletions(-)
+ create mode 100644 src/internal/safefilepath/path.go
+ create mode 100644 src/internal/safefilepath/path_other.go
+ create mode 100644 src/internal/safefilepath/path_test.go
+ create mode 100644 src/internal/safefilepath/path_windows.go
+
+diff --git a/src/go/build/deps_test.go b/src/go/build/deps_test.go
+index 45e2f25..dc3bb8c 100644
+--- a/src/go/build/deps_test.go
++++ b/src/go/build/deps_test.go
+@@ -165,6 +165,7 @@ var depsRules = `
+ io/fs
+ < internal/testlog
+ < internal/poll
++ < internal/safefilepath
+ < os
+ < os/signal;
+
+diff --git a/src/internal/safefilepath/path.go b/src/internal/safefilepath/path.go
+new file mode 100644
+index 0000000..0f0a270
+--- /dev/null
++++ b/src/internal/safefilepath/path.go
+@@ -0,0 +1,21 @@
++// Copyright 2022 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.
++
++// Package safefilepath manipulates operating-system file paths.
++package safefilepath
++
++import (
++ "errors"
++)
++
++var errInvalidPath = errors.New("invalid path")
++
++// FromFS converts a slash-separated path into an operating-system path.
++//
++// FromFS returns an error if the path cannot be represented by the operating
++// system. For example, paths containing '\' and ':' characters are rejected
++// on Windows.
++func FromFS(path string) (string, error) {
++ return fromFS(path)
++}
+diff --git a/src/internal/safefilepath/path_other.go b/src/internal/safefilepath/path_other.go
+new file mode 100644
+index 0000000..f93da18
+--- /dev/null
++++ b/src/internal/safefilepath/path_other.go
+@@ -0,0 +1,23 @@
++// Copyright 2022 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.
++
++//go:build !windows
++
++package safefilepath
++
++import "runtime"
++
++func fromFS(path string) (string, error) {
++ if runtime.GOOS == "plan9" {
++ if len(path) > 0 && path[0] == '#' {
++ return path, errInvalidPath
++ }
++ }
++ for i := range path {
++ if path[i] == 0 {
++ return "", errInvalidPath
++ }
++ }
++ return path, nil
++}
+diff --git a/src/internal/safefilepath/path_test.go b/src/internal/safefilepath/path_test.go
+new file mode 100644
+index 0000000..dc662c1
+--- /dev/null
++++ b/src/internal/safefilepath/path_test.go
+@@ -0,0 +1,88 @@
++// Copyright 2022 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.
++
++package safefilepath_test
++
++import (
++ "internal/safefilepath"
++ "os"
++ "path/filepath"
++ "runtime"
++ "testing"
++)
++
++type PathTest struct {
++ path, result string
++}
++
++const invalid = ""
++
++var fspathtests = []PathTest{
++ {".", "."},
++ {"/a/b/c", "/a/b/c"},
++ {"a\x00b", invalid},
++}
++
++var winreservedpathtests = []PathTest{
++ {`a\b`, `a\b`},
++ {`a:b`, `a:b`},
++ {`a/b:c`, `a/b:c`},
++ {`NUL`, `NUL`},
++ {`./com1`, `./com1`},
++ {`a/nul/b`, `a/nul/b`},
++}
++
++// Whether a reserved name with an extension is reserved or not varies by
++// Windows version.
++var winreservedextpathtests = []PathTest{
++ {"nul.txt", "nul.txt"},
++ {"a/nul.txt/b", "a/nul.txt/b"},
++}
++
++var plan9reservedpathtests = []PathTest{
++ {`#c`, `#c`},
++}
++
++func TestFromFS(t *testing.T) {
++ switch runtime.GOOS {
++ case "windows":
++ if canWriteFile(t, "NUL") {
++ t.Errorf("can unexpectedly write a file named NUL on Windows")
++ }
++ if canWriteFile(t, "nul.txt") {
++ fspathtests = append(fspathtests, winreservedextpathtests...)
++ } else {
++ winreservedpathtests = append(winreservedpathtests, winreservedextpathtests...)
++ }
++ for i := range winreservedpathtests {
++ winreservedpathtests[i].result = invalid
++ }
++ for i := range fspathtests {
++ fspathtests[i].result = filepath.FromSlash(fspathtests[i].result)
++ }
++ case "plan9":
++ for i := range plan9reservedpathtests {
++ plan9reservedpathtests[i].result = invalid
++ }
++ }
++ tests := fspathtests
++ tests = append(tests, winreservedpathtests...)
++ tests = append(tests, plan9reservedpathtests...)
++ for _, test := range tests {
++ got, err := safefilepath.FromFS(test.path)
++ if (got == "") != (err != nil) {
++ t.Errorf(`FromFS(%q) = %q, %v; want "" only if err != nil`, test.path, got, err)
++ }
++ if got != test.result {
++ t.Errorf("FromFS(%q) = %q, %v; want %q", test.path, got, err, test.result)
++ }
++ }
++}
++
++func canWriteFile(t *testing.T, name string) bool {
++ path := filepath.Join(t.TempDir(), name)
++ os.WriteFile(path, []byte("ok"), 0666)
++ b, _ := os.ReadFile(path)
++ return string(b) == "ok"
++}
+diff --git a/src/internal/safefilepath/path_windows.go b/src/internal/safefilepath/path_windows.go
+new file mode 100644
+index 0000000..909c150
+--- /dev/null
++++ b/src/internal/safefilepath/path_windows.go
+@@ -0,0 +1,95 @@
++// Copyright 2022 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.
++
++package safefilepath
++
++import (
++ "syscall"
++ "unicode/utf8"
++)
++
++func fromFS(path string) (string, error) {
++ if !utf8.ValidString(path) {
++ return "", errInvalidPath
++ }
++ for len(path) > 1 && path[0] == '/' && path[1] == '/' {
++ path = path[1:]
++ }
++ containsSlash := false
++ for p := path; p != ""; {
++ // Find the next path element.
++ i := 0
++ dot := -1
++ for i < len(p) && p[i] != '/' {
++ switch p[i] {
++ case 0, '\\', ':':
++ return "", errInvalidPath
++ case '.':
++ if dot < 0 {
++ dot = i
++ }
++ }
++ i++
++ }
++ part := p[:i]
++ if i < len(p) {
++ containsSlash = true
++ p = p[i+1:]
++ } else {
++ p = ""
++ }
++ // Trim the extension and look for a reserved name.
++ base := part
++ if dot >= 0 {
++ base = part[:dot]
++ }
++ if isReservedName(base) {
++ if dot < 0 {
++ return "", errInvalidPath
++ }
++ // The path element is a reserved name with an extension.
++ // Some Windows versions consider this a reserved name,
++ // while others do not. Use FullPath to see if the name is
++ // reserved.
++ if p, _ := syscall.FullPath(part); len(p) >= 4 && p[:4] == `\\.\` {
++ return "", errInvalidPath
++ }
++ }
++ }
++ if containsSlash {
++ // We can't depend on strings, so substitute \ for / manually.
++ buf := []byte(path)
++ for i, b := range buf {
++ if b == '/' {
++ buf[i] = '\\'
++ }
++ }
++ path = string(buf)
++ }
++ return path, nil
++}
++
++// isReservedName reports if name is a Windows reserved device name.
++// It does not detect names with an extension, which are also reserved on some Windows versions.
++//
++// For details, search for PRN in
++// https://docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file.
++func isReservedName(name string) bool {
++ if 3 <= len(name) && len(name) <= 4 {
++ switch string([]byte{toUpper(name[0]), toUpper(name[1]), toUpper(name[2])}) {
++ case "CON", "PRN", "AUX", "NUL":
++ return len(name) == 3
++ case "COM", "LPT":
++ return len(name) == 4 && '1' <= name[3] && name[3] <= '9'
++ }
++ }
++ return false
++}
++
++func toUpper(c byte) byte {
++ if 'a' <= c && c <= 'z' {
++ return c - ('a' - 'A')
++ }
++ return c
++}
+diff --git a/src/net/http/fs.go b/src/net/http/fs.go
+index 57e731e..43ee4b5 100644
+--- a/src/net/http/fs.go
++++ b/src/net/http/fs.go
+@@ -9,6 +9,7 @@ package http
+ import (
+ "errors"
+ "fmt"
++ "internal/safefilepath"
+ "io"
+ "io/fs"
+ "mime"
+@@ -69,14 +70,15 @@ func mapDirOpenError(originalErr error, name string) error {
+ // Open implements FileSystem using os.Open, opening files for reading rooted
+ // and relative to the directory d.
+ func (d Dir) Open(name string) (File, error) {
+- if filepath.Separator != '/' && strings.ContainsRune(name, filepath.Separator) {
+- return nil, errors.New("http: invalid character in file path")
++ path, err := safefilepath.FromFS(path.Clean("/" + name))
++ if err != nil {
++ return nil, errors.New("http: invalid or unsafe file path")
+ }
+ dir := string(d)
+ if dir == "" {
+ dir = "."
+ }
+- fullName := filepath.Join(dir, filepath.FromSlash(path.Clean("/"+name)))
++ fullName := filepath.Join(dir, path)
+ f, err := os.Open(fullName)
+ if err != nil {
+ return nil, mapDirOpenError(err, fullName)
+diff --git a/src/net/http/fs_test.go b/src/net/http/fs_test.go
+index b42ade1..941448a 100644
+--- a/src/net/http/fs_test.go
++++ b/src/net/http/fs_test.go
+@@ -648,6 +648,34 @@ func TestFileServerZeroByte(t *testing.T) {
+ }
+ }
+
++func TestFileServerNamesEscape(t *testing.T) {
++ t.Run("h1", func(t *testing.T) {
++ testFileServerNamesEscape(t, h1Mode)
++ })
++ t.Run("h2", func(t *testing.T) {
++ testFileServerNamesEscape(t, h2Mode)
++ })
++}
++func testFileServerNamesEscape(t *testing.T, h2 bool) {
++ defer afterTest(t)
++ ts := newClientServerTest(t, h2, FileServer(Dir("testdata"))).ts
++ defer ts.Close()
++ for _, path := range []string{
++ "/../testdata/file",
++ "/NUL", // don't read from device files on Windows
++ } {
++ res, err := ts.Client().Get(ts.URL + path)
++ if err != nil {
++ t.Fatal(err)
++ }
++ res.Body.Close()
++ if res.StatusCode < 400 || res.StatusCode > 599 {
++ t.Errorf("Get(%q): got status %v, want 4xx or 5xx", path, res.StatusCode)
++ }
++
++ }
++}
++
+ type fakeFileInfo struct {
+ dir bool
+ basename string
+diff --git a/src/os/file.go b/src/os/file.go
+index e717f17..cb87158 100644
+--- a/src/os/file.go
++++ b/src/os/file.go
+@@ -37,12 +37,12 @@
+ // Note: The maximum number of concurrent operations on a File may be limited by
+ // the OS or the system. The number should be high, but exceeding it may degrade
+ // performance or cause other issues.
+-//
+ package os
+
+ import (
+ "errors"
+ "internal/poll"
++ "internal/safefilepath"
+ "internal/testlog"
+ "internal/unsafeheader"
+ "io"
+@@ -623,6 +623,8 @@ func isWindowsNulName(name string) bool {
+ // the /prefix tree, then using DirFS does not stop the access any more than using
+ // os.Open does. DirFS is therefore not a general substitute for a chroot-style security
+ // mechanism when the directory tree contains arbitrary content.
++//
++// The directory dir must not be "".
+ func DirFS(dir string) fs.FS {
+ return dirFS(dir)
+ }
+@@ -641,10 +643,11 @@ func containsAny(s, chars string) bool {
+ type dirFS string
+
+ func (dir dirFS) Open(name string) (fs.File, error) {
+- if !fs.ValidPath(name) || runtime.GOOS == "windows" && containsAny(name, `\:`) {
+- return nil, &PathError{Op: "open", Path: name, Err: ErrInvalid}
++ fullname, err := dir.join(name)
++ if err != nil {
++ return nil, &PathError{Op: "stat", Path: name, Err: err}
+ }
+- f, err := Open(string(dir) + "/" + name)
++ f, err := Open(fullname)
+ if err != nil {
+ return nil, err // nil fs.File
+ }
+@@ -652,16 +655,35 @@ func (dir dirFS) Open(name string) (fs.File, error) {
+ }
+
+ func (dir dirFS) Stat(name string) (fs.FileInfo, error) {
+- if !fs.ValidPath(name) || runtime.GOOS == "windows" && containsAny(name, `\:`) {
+- return nil, &PathError{Op: "stat", Path: name, Err: ErrInvalid}
++ fullname, err := dir.join(name)
++ if err != nil {
++ return nil, &PathError{Op: "stat", Path: name, Err: err}
+ }
+- f, err := Stat(string(dir) + "/" + name)
++ f, err := Stat(fullname)
+ if err != nil {
+ return nil, err
+ }
+ return f, nil
+ }
+
++// join returns the path for name in dir.
++func (dir dirFS) join(name string) (string, error) {
++ if dir == "" {
++ return "", errors.New("os: DirFS with empty root")
++ }
++ if !fs.ValidPath(name) {
++ return "", ErrInvalid
++ }
++ name, err := safefilepath.FromFS(name)
++ if err != nil {
++ return "", ErrInvalid
++ }
++ if IsPathSeparator(dir[len(dir)-1]) {
++ return string(dir) + name, nil
++ }
++ return string(dir) + string(PathSeparator) + name, nil
++}
++
+ // ReadFile reads the named file and returns the contents.
+ // A successful call returns err == nil, not err == EOF.
+ // Because ReadFile reads the whole file, it does not treat an EOF from Read
+diff --git a/src/os/os_test.go b/src/os/os_test.go
+index 506f1fb..be269bb 100644
+--- a/src/os/os_test.go
++++ b/src/os/os_test.go
+@@ -2702,6 +2702,44 @@ func TestDirFS(t *testing.T) {
+ if err == nil {
+ t.Fatalf(`Open testdata\dirfs succeeded`)
+ }
++
++ // Test that Open does not open Windows device files.
++ _, err = d.Open(`NUL`)
++ if err == nil {
++ t.Errorf(`Open NUL succeeded`)
++ }
++}
++
++func TestDirFSRootDir(t *testing.T) {
++ cwd, err := os.Getwd()
++ if err != nil {
++ t.Fatal(err)
++ }
++ cwd = cwd[len(filepath.VolumeName(cwd)):] // trim volume prefix (C:) on Windows
++ cwd = filepath.ToSlash(cwd) // convert \ to /
++ cwd = strings.TrimPrefix(cwd, "/") // trim leading /
++
++ // Test that Open can open a path starting at /.
++ d := DirFS("/")
++ f, err := d.Open(cwd + "/testdata/dirfs/a")
++ if err != nil {
++ t.Fatal(err)
++ }
++ f.Close()
++}
++
++func TestDirFSEmptyDir(t *testing.T) {
++ d := DirFS("")
++ cwd, _ := os.Getwd()
++ for _, path := range []string{
++ "testdata/dirfs/a", // not DirFS(".")
++ filepath.ToSlash(cwd) + "/testdata/dirfs/a", // not DirFS("/")
++ } {
++ _, err := d.Open(path)
++ if err == nil {
++ t.Fatalf(`DirFS("").Open(%q) succeeded`, path)
++ }
++ }
+ }
+
+ func TestDirFSPathsValid(t *testing.T) {
--
2.40.0