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hirochachachaianlancetaylor
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cmd/cgo: reject names that are likely to be mangled C name
Fixes golang#28721 Change-Id: I00356f3a9b0c2fb21dc9c2237dd5296fcb3b319b Reviewed-on: https://go-review.googlesource.com/c/152657 Run-TryBot: Ian Lance Taylor <[email protected]> Reviewed-by: Ian Lance Taylor <[email protected]>
1 parent 897e080 commit 5e17278

5 files changed

Lines changed: 55 additions & 1 deletion

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‎misc/cgo/errors/errors_test.go‎

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@@ -121,6 +121,7 @@ func TestReportsTypeErrors(t *testing.T) {
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"issue16591.go",
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"issue18452.go",
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"issue18889.go",
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"issue28721.go",
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} {
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check(t, file)
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}

‎misc/cgo/errors/src/issue28721.go‎

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@@ -0,0 +1,29 @@
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// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// cgo should reject the use of mangled C names.
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package main
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/*
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typedef struct a {
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int i;
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} a;
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void fn(void) {}
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*/
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import "C"
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type B _Ctype_struct_a // ERROR HERE
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var a _Ctype_struct_a // ERROR HERE
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type A struct {
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a *_Ctype_struct_a // ERROR HERE
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}
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var notExist _Ctype_NotExist // ERROR HERE
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func main() {
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_Cfunc_fn() // ERROR HERE
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}

‎src/cmd/cgo/ast.go‎

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@@ -145,6 +145,7 @@ func (f *File) ParseGo(name string, src []byte) {
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if f.Ref == nil {
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f.Ref = make([]*Ref, 0, 8)
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}
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f.walk(ast2, ctxProg, (*File).validateIdents)
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f.walk(ast2, ctxProg, (*File).saveExprs)
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// Accumulate exported functions.
@@ -181,6 +182,14 @@ func commentText(g *ast.CommentGroup) string {
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return strings.Join(pieces, "")
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}
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func (f *File) validateIdents(x interface{}, context astContext) {
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if x, ok := x.(*ast.Ident); ok {
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if f.isMangledName(x.Name) {
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error_(x.Pos(), "identifier %q may conflict with identifiers generated by cgo", x.Name)
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}
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}
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}
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// Save various references we are going to need later.
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func (f *File) saveExprs(x interface{}, context astContext) {
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switch x := x.(type) {

‎src/cmd/cgo/gcc.go‎

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@@ -719,6 +719,19 @@ func (p *Package) mangleName(n *Name) {
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n.Mangle = prefix + n.Kind + "_" + n.Go
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}
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func (f *File) isMangledName(s string) bool {
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prefix := "_C"
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if strings.HasPrefix(s, prefix) {
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t := s[len(prefix):]
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for _, k := range nameKinds {
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if strings.HasPrefix(t, k+"_") {
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return true
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}
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}
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}
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return false
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}
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// rewriteCalls rewrites all calls that pass pointers to check that
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// they follow the rules for passing pointers between Go and C.
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// This reports whether the package needs to import unsafe as _cgo_unsafe.

‎src/cmd/cgo/main.go‎

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@@ -106,13 +106,15 @@ func (r *Ref) Pos() token.Pos {
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return (*r.Expr).Pos()
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}
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var nameKinds = []string{"iconst", "fconst", "sconst", "type", "var", "fpvar", "func", "macro", "not-type"}
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// A Name collects information about C.xxx.
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type Name struct {
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Go string // name used in Go referring to package C
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Mangle string // name used in generated Go
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C string // name used in C
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Define string // #define expansion
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Kind string // "iconst", "fconst", "sconst", "type", "var", "fpvar", "func", "macro", "not-type"
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Kind string // one of the nameKinds
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Type *Type // the type of xxx
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FuncType *FuncType
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AddError bool

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