]> Cypherpunks repositories - gostls13.git/commitdiff
cmd/go: sanitize go env outputs
authorMichael Matloob <matloob@golang.org>
Mon, 24 Apr 2023 20:57:28 +0000 (16:57 -0400)
committerMichael Matloob <matloob@golang.org>
Fri, 5 May 2023 14:28:38 +0000 (14:28 +0000)
go env, without any arguments, outputs the environment variables in
the form of a script that can be run on the host OS. On Unix, single
quote the strings and place single quotes themselves outside the
single quoted strings. On windows use the set "var=val" syntax with
the quote starting before the variable.

Fixes #58508

Change-Id: Iecd379a4af7285ea9b2024f0202250c74fd9a2bd
Reviewed-on: https://go-review.googlesource.com/c/go/+/488375
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
Run-TryBot: Michael Matloob <matloob@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Quim Muntal <quimmuntal@gmail.com>
src/cmd/go/internal/envcmd/env.go
src/cmd/go/internal/envcmd/env_test.go [new file with mode: 0644]
src/cmd/go/testdata/script/env_sanitize.txt [new file with mode: 0644]
src/cmd/go/testdata/script/work_env.txt

index 66ef5ceee3cefde68471ed34159a6da07f1ebc9e..c865cb8a991d43c6f0a67f9c9e8ec56f4b02de5e 100644 (file)
@@ -6,6 +6,7 @@
 package envcmd
 
 import (
+       "bytes"
        "context"
        "encoding/json"
        "fmt"
@@ -17,6 +18,7 @@ import (
        "runtime"
        "sort"
        "strings"
+       "unicode"
        "unicode/utf8"
 
        "cmd/go/internal/base"
@@ -413,9 +415,12 @@ func checkBuildConfig(add map[string]string, del map[string]bool) error {
 func PrintEnv(w io.Writer, env []cfg.EnvVar) {
        for _, e := range env {
                if e.Name != "TERM" {
+                       if runtime.GOOS != "plan9" && bytes.Contains([]byte(e.Value), []byte{0}) {
+                               base.Fatalf("go: internal error: encountered null byte in environment variable %s on non-plan9 platform", e.Name)
+                       }
                        switch runtime.GOOS {
                        default:
-                               fmt.Fprintf(w, "%s=\"%s\"\n", e.Name, e.Value)
+                               fmt.Fprintf(w, "%s=%s\n", e.Name, shellQuote(e.Value))
                        case "plan9":
                                if strings.IndexByte(e.Value, '\x00') < 0 {
                                        fmt.Fprintf(w, "%s='%s'\n", e.Name, strings.ReplaceAll(e.Value, "'", "''"))
@@ -426,17 +431,68 @@ func PrintEnv(w io.Writer, env []cfg.EnvVar) {
                                                if x > 0 {
                                                        fmt.Fprintf(w, " ")
                                                }
+                                               // TODO(#59979): Does this need to be quoted like above?
                                                fmt.Fprintf(w, "%s", s)
                                        }
                                        fmt.Fprintf(w, ")\n")
                                }
                        case "windows":
-                               fmt.Fprintf(w, "set %s=%s\n", e.Name, e.Value)
+                               if hasNonGraphic(e.Value) {
+                                       base.Errorf("go: stripping unprintable or unescapable characters from %%%q%%", e.Name)
+                               }
+                               fmt.Fprintf(w, "set %s=%s\n", e.Name, batchEscape(e.Value))
                        }
                }
        }
 }
 
+func hasNonGraphic(s string) bool {
+       for _, c := range []byte(s) {
+               if c == '\r' || c == '\n' || (!unicode.IsGraphic(rune(c)) && !unicode.IsSpace(rune(c))) {
+                       return true
+               }
+       }
+       return false
+}
+
+func shellQuote(s string) string {
+       var b bytes.Buffer
+       b.WriteByte('\'')
+       for _, x := range []byte(s) {
+               if x == '\'' {
+                       // Close the single quoted string, add an escaped single quote,
+                       // and start another single quoted string.
+                       b.WriteString(`'\''`)
+               } else {
+                       b.WriteByte(x)
+               }
+       }
+       b.WriteByte('\'')
+       return b.String()
+}
+
+func batchEscape(s string) string {
+       var b bytes.Buffer
+       for _, x := range []byte(s) {
+               if x == '\r' || x == '\n' || (!unicode.IsGraphic(rune(x)) && !unicode.IsSpace(rune(x))) {
+                       b.WriteRune(unicode.ReplacementChar)
+                       continue
+               }
+               switch x {
+               case '%':
+                       b.WriteString("%%")
+               case '<', '>', '|', '&', '^':
+                       // These are special characters that need to be escaped with ^. See
+                       // https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/set_1.
+                       b.WriteByte('^')
+                       b.WriteByte(x)
+               default:
+                       b.WriteByte(x)
+               }
+       }
+       return b.String()
+}
+
 func printEnvAsJSON(env []cfg.EnvVar) {
        m := make(map[string]string)
        for _, e := range env {
diff --git a/src/cmd/go/internal/envcmd/env_test.go b/src/cmd/go/internal/envcmd/env_test.go
new file mode 100644 (file)
index 0000000..32d99fd
--- /dev/null
@@ -0,0 +1,94 @@
+// 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 unix || windows
+
+package envcmd
+
+import (
+       "bytes"
+       "cmd/go/internal/cfg"
+       "fmt"
+       "internal/testenv"
+       "os"
+       "os/exec"
+       "path/filepath"
+       "runtime"
+       "testing"
+       "unicode"
+)
+
+func FuzzPrintEnvEscape(f *testing.F) {
+       f.Add(`$(echo 'cc"'; echo 'OOPS="oops')`)
+       f.Add("$(echo shell expansion 1>&2)")
+       f.Add("''")
+       f.Add(`C:\"Program Files"\`)
+       f.Add(`\\"Quoted Host"\\share`)
+       f.Add("\xfb")
+       f.Add("0")
+       f.Add("")
+       f.Add("''''''''")
+       f.Add("\r")
+       f.Add("\n")
+       f.Add("E,%")
+       f.Fuzz(func(t *testing.T, s string) {
+               t.Parallel()
+
+               for _, c := range []byte(s) {
+                       if c == 0 {
+                               t.Skipf("skipping %q: contains a null byte. Null bytes can't occur in the environment"+
+                                       " outside of Plan 9, which has different code path than Windows and Unix that this test"+
+                                       " isn't testing.", s)
+                       }
+                       if c > unicode.MaxASCII {
+                               t.Skipf("skipping %#q: contains a non-ASCII character %q", s, c)
+                       }
+                       if !unicode.IsGraphic(rune(c)) && !unicode.IsSpace(rune(c)) {
+                               t.Skipf("skipping %#q: contains non-graphic character %q", s, c)
+                       }
+                       if runtime.GOOS == "windows" && c == '\r' || c == '\n' {
+                               t.Skipf("skipping %#q on Windows: contains unescapable character %q", s, c)
+                       }
+               }
+
+               var b bytes.Buffer
+               if runtime.GOOS == "windows" {
+                       b.WriteString("@echo off\n")
+               }
+               PrintEnv(&b, []cfg.EnvVar{{Name: "var", Value: s}})
+               var want string
+               if runtime.GOOS == "windows" {
+                       fmt.Fprintf(&b, "echo \"%%var%%\"\n")
+                       want += "\"" + s + "\"\r\n"
+               } else {
+                       fmt.Fprintf(&b, "printf '%%s\\n' \"$var\"\n")
+                       want += s + "\n"
+               }
+               scriptfilename := "script.sh"
+               if runtime.GOOS == "windows" {
+                       scriptfilename = "script.bat"
+               }
+               scriptfile := filepath.Join(t.TempDir(), scriptfilename)
+               if err := os.WriteFile(scriptfile, b.Bytes(), 0777); err != nil {
+                       t.Fatal(err)
+               }
+               t.Log(b.String())
+               var cmd *exec.Cmd
+               if runtime.GOOS == "windows" {
+                       cmd = testenv.Command(t, "cmd.exe", "/C", scriptfile)
+               } else {
+                       cmd = testenv.Command(t, "sh", "-c", scriptfile)
+               }
+               out, err := cmd.Output()
+               t.Log(string(out))
+               if err != nil {
+                       t.Fatal(err)
+               }
+
+               if string(out) != want {
+                       t.Fatalf("output of running PrintEnv script and echoing variable: got: %q, want: %q",
+                               string(out), want)
+               }
+       })
+}
diff --git a/src/cmd/go/testdata/script/env_sanitize.txt b/src/cmd/go/testdata/script/env_sanitize.txt
new file mode 100644 (file)
index 0000000..cc4d23a
--- /dev/null
@@ -0,0 +1,5 @@
+env GOFLAGS='$(echo ''cc"''; echo ''OOPS="oops'')'
+go env
+[GOOS:darwin] stdout 'GOFLAGS=''\$\(echo ''\\''''cc"''\\''''; echo ''\\''''OOPS="oops''\\''''\)'''
+[GOOS:linux] stdout 'GOFLAGS=''\$\(echo ''\\''''cc"''\\''''; echo ''\\''''OOPS="oops''\\''''\)'''
+[GOOS:windows] stdout 'set GOFLAGS=\$\(echo ''cc"''; echo ''OOPS="oops''\)'
index 511bb4e2cb62ea9abb7b995cf2516babe02fa38c..8b1779ea703725e0b00196b708a68ce3b187049f 100644 (file)
@@ -1,7 +1,7 @@
 go env GOWORK
 stdout '^'$GOPATH'[\\/]src[\\/]go.work$'
 go env
-stdout '^(set )?GOWORK="?'$GOPATH'[\\/]src[\\/]go.work"?$'
+stdout '^(set )?GOWORK=''?'$GOPATH'[\\/]src[\\/]go.work''?$'
 
 cd ..
 go env GOWORK