mirror of
https://github.com/golang/go
synced 2024-11-20 09:24:50 -07:00
55 lines
1.4 KiB
Go
55 lines
1.4 KiB
Go
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// +build amd64,linux
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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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package cgotest
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// Test that C.GoString uses IndexByte in safe manner.
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/*
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#include <sys/mman.h>
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// Returns string with null byte at the last valid address
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char* dangerousString1() {
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int pageSize = 4096;
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char *data = mmap(0, 2 * pageSize, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, 0, 0);
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mprotect(data + pageSize,pageSize,PROT_NONE);
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int start = pageSize - 123 - 1; // last 123 bytes of first page + 1 null byte
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int i = start;
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for (; i < pageSize; i++) {
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data[i] = 'x';
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}
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data[pageSize -1 ] = 0;
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return data+start;
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}
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char* dangerousString2() {
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int pageSize = 4096;
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char *data = mmap(0, 3 * pageSize, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, 0, 0);
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mprotect(data + 2 * pageSize,pageSize,PROT_NONE);
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int start = pageSize - 123 - 1; // last 123 bytes of first page + 1 null byte
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int i = start;
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for (; i < 2 * pageSize; i++) {
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data[i] = 'x';
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}
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data[2*pageSize -1 ] = 0;
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return data+start;
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}
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*/
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import "C"
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import (
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"testing"
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)
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func test24206(t *testing.T) {
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if l := len(C.GoString(C.dangerousString1())); l != 123 {
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t.Errorf("Incorrect string length - got %d, want 123", l)
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}
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if l := len(C.GoString(C.dangerousString2())); l != 4096+123 {
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t.Errorf("Incorrect string length - got %d, want %d", l, 4096+123)
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}
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}
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