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-rw-r--r--misc/cgo/errors/badsym_test.go219
1 files changed, 219 insertions, 0 deletions
diff --git a/misc/cgo/errors/badsym_test.go b/misc/cgo/errors/badsym_test.go
new file mode 100644
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+++ b/misc/cgo/errors/badsym_test.go
@@ -0,0 +1,219 @@
+// Copyright 2020 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 errorstest
+
+import (
+ "bytes"
+ "os"
+ "os/exec"
+ "path/filepath"
+ "strings"
+ "testing"
+ "unicode"
+)
+
+// A manually modified object file could pass unexpected characters
+// into the files generated by cgo.
+
+const magicInput = "abcdefghijklmnopqrstuvwxyz0123"
+const magicReplace = "\n//go:cgo_ldflag \"-badflag\"\n//"
+
+const cSymbol = "BadSymbol" + magicInput + "Name"
+const cDefSource = "int " + cSymbol + " = 1;"
+const cRefSource = "extern int " + cSymbol + "; int F() { return " + cSymbol + "; }"
+
+// goSource is the source code for the trivial Go file we use.
+// We will replace TMPDIR with the temporary directory name.
+const goSource = `
+package main
+
+// #cgo LDFLAGS: TMPDIR/cbad.o TMPDIR/cbad.so
+// extern int F();
+import "C"
+
+func main() {
+ println(C.F())
+}
+`
+
+func TestBadSymbol(t *testing.T) {
+ dir := t.TempDir()
+
+ mkdir := func(base string) string {
+ ret := filepath.Join(dir, base)
+ if err := os.Mkdir(ret, 0755); err != nil {
+ t.Fatal(err)
+ }
+ return ret
+ }
+
+ cdir := mkdir("c")
+ godir := mkdir("go")
+
+ makeFile := func(mdir, base, source string) string {
+ ret := filepath.Join(mdir, base)
+ if err := os.WriteFile(ret, []byte(source), 0644); err != nil {
+ t.Fatal(err)
+ }
+ return ret
+ }
+
+ cDefFile := makeFile(cdir, "cdef.c", cDefSource)
+ cRefFile := makeFile(cdir, "cref.c", cRefSource)
+
+ ccCmd := cCompilerCmd(t)
+
+ cCompile := func(arg, base, src string) string {
+ out := filepath.Join(cdir, base)
+ run := append(ccCmd, arg, "-o", out, src)
+ output, err := exec.Command(run[0], run[1:]...).CombinedOutput()
+ if err != nil {
+ t.Log(run)
+ t.Logf("%s", output)
+ t.Fatal(err)
+ }
+ if err := os.Remove(src); err != nil {
+ t.Fatal(err)
+ }
+ return out
+ }
+
+ // Build a shared library that defines a symbol whose name
+ // contains magicInput.
+
+ cShared := cCompile("-shared", "c.so", cDefFile)
+
+ // Build an object file that refers to the symbol whose name
+ // contains magicInput.
+
+ cObj := cCompile("-c", "c.o", cRefFile)
+
+ // Rewrite the shared library and the object file, replacing
+ // magicInput with magicReplace. This will have the effect of
+ // introducing a symbol whose name looks like a cgo command.
+ // The cgo tool will use that name when it generates the
+ // _cgo_import.go file, thus smuggling a magic //go:cgo_ldflag
+ // pragma into a Go file. We used to not check the pragmas in
+ // _cgo_import.go.
+
+ rewrite := func(from, to string) {
+ obj, err := os.ReadFile(from)
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ if bytes.Count(obj, []byte(magicInput)) == 0 {
+ t.Fatalf("%s: did not find magic string", from)
+ }
+
+ if len(magicInput) != len(magicReplace) {
+ t.Fatalf("internal test error: different magic lengths: %d != %d", len(magicInput), len(magicReplace))
+ }
+
+ obj = bytes.ReplaceAll(obj, []byte(magicInput), []byte(magicReplace))
+
+ if err := os.WriteFile(to, obj, 0644); err != nil {
+ t.Fatal(err)
+ }
+ }
+
+ cBadShared := filepath.Join(godir, "cbad.so")
+ rewrite(cShared, cBadShared)
+
+ cBadObj := filepath.Join(godir, "cbad.o")
+ rewrite(cObj, cBadObj)
+
+ goSourceBadObject := strings.ReplaceAll(goSource, "TMPDIR", godir)
+ makeFile(godir, "go.go", goSourceBadObject)
+
+ makeFile(godir, "go.mod", "module badsym")
+
+ // Try to build our little package.
+ cmd := exec.Command("go", "build", "-ldflags=-v")
+ cmd.Dir = godir
+ output, err := cmd.CombinedOutput()
+
+ // The build should fail, but we want it to fail because we
+ // detected the error, not because we passed a bad flag to the
+ // C linker.
+
+ if err == nil {
+ t.Errorf("go build succeeded unexpectedly")
+ }
+
+ t.Logf("%s", output)
+
+ for _, line := range bytes.Split(output, []byte("\n")) {
+ if bytes.Contains(line, []byte("dynamic symbol")) && bytes.Contains(line, []byte("contains unsupported character")) {
+ // This is the error from cgo.
+ continue
+ }
+
+ // We passed -ldflags=-v to see the external linker invocation,
+ // which should not include -badflag.
+ if bytes.Contains(line, []byte("-badflag")) {
+ t.Error("output should not mention -badflag")
+ }
+
+ // Also check for compiler errors, just in case.
+ // GCC says "unrecognized command line option".
+ // clang says "unknown argument".
+ if bytes.Contains(line, []byte("unrecognized")) || bytes.Contains(output, []byte("unknown")) {
+ t.Error("problem should have been caught before invoking C linker")
+ }
+ }
+}
+
+func cCompilerCmd(t *testing.T) []string {
+ cc := []string{goEnv(t, "CC")}
+
+ out := goEnv(t, "GOGCCFLAGS")
+ quote := '\000'
+ start := 0
+ lastSpace := true
+ backslash := false
+ s := string(out)
+ for i, c := range s {
+ if quote == '\000' && unicode.IsSpace(c) {
+ if !lastSpace {
+ cc = append(cc, s[start:i])
+ lastSpace = true
+ }
+ } else {
+ if lastSpace {
+ start = i
+ lastSpace = false
+ }
+ if quote == '\000' && !backslash && (c == '"' || c == '\'') {
+ quote = c
+ backslash = false
+ } else if !backslash && quote == c {
+ quote = '\000'
+ } else if (quote == '\000' || quote == '"') && !backslash && c == '\\' {
+ backslash = true
+ } else {
+ backslash = false
+ }
+ }
+ }
+ if !lastSpace {
+ cc = append(cc, s[start:])
+ }
+
+ // Force reallocation (and avoid aliasing bugs) for tests that append to cc.
+ cc = cc[:len(cc):len(cc)]
+
+ return cc
+}
+
+func goEnv(t *testing.T, key string) string {
+ out, err := exec.Command("go", "env", key).CombinedOutput()
+ if err != nil {
+ t.Logf("go env %s\n", key)
+ t.Logf("%s", out)
+ t.Fatal(err)
+ }
+ return strings.TrimSpace(string(out))
+}