codekingpro/portable-devtools

1// Copyright 2024 The Go Authors. All rights reserved.2// Use of this source code is governed by a BSD-style3// license that can be found in the LICENSE file.4 5package subtle_test6 7import (8	"crypto/subtle"9	"syscall"10	"testing"11)12 13// dangerousSlice returns a slice which is immediately14// preceded and followed by a faulting page.15// Copied from the bytes package tests.16func dangerousSlice(t *testing.T) []byte {17	pagesize := syscall.Getpagesize()18	b, err := syscall.Mmap(0, 0, 3*pagesize, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_ANONYMOUS|syscall.MAP_PRIVATE)19	if err != nil {20		t.Fatalf("mmap failed %s", err)21	}22	err = syscall.Mprotect(b[:pagesize], syscall.PROT_NONE)23	if err != nil {24		t.Fatalf("mprotect low failed %s\n", err)25	}26	err = syscall.Mprotect(b[2*pagesize:], syscall.PROT_NONE)27	if err != nil {28		t.Fatalf("mprotect high failed %s\n", err)29	}30	return b[pagesize : 2*pagesize]31}32 33func TestXORBytesBoundary(t *testing.T) {34	safe := make([]byte, syscall.Getpagesize()*2)35	spicy := dangerousSlice(t)36	for i := 1; i <= syscall.Getpagesize(); i++ {37		start := spicy[:i]38		end := spicy[len(spicy)-i:]39		subtle.XORBytes(end, safe, safe[:i])40		subtle.XORBytes(start, safe, safe[:i])41		subtle.XORBytes(safe, start, safe)42		subtle.XORBytes(safe, end, safe)43		subtle.XORBytes(safe, safe, start)44		subtle.XORBytes(safe, safe, end)45	}46}47