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/*
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "safe_copy.h"
#include <errno.h>
#include <string.h>
#include <sys/user.h>
#include "android-base/logging.h"
#include "globals.h"
#include "gtest/gtest.h"
#include "mman.h"
namespace art {
#if defined(__linux__)
TEST(SafeCopyTest, smoke) {
DCHECK_EQ(kPageSize, static_cast<decltype(kPageSize)>(PAGE_SIZE));
// Map four pages, mark the second one as PROT_NONE, unmap the last one.
void* map = mmap(nullptr, kPageSize * 4, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
ASSERT_NE(MAP_FAILED, map);
char* page1 = static_cast<char*>(map);
char* page2 = page1 + kPageSize;
char* page3 = page2 + kPageSize;
char* page4 = page3 + kPageSize;
ASSERT_EQ(0, mprotect(page1 + kPageSize, kPageSize, PROT_NONE));
ASSERT_EQ(0, munmap(page4, kPageSize));
page1[0] = 'a';
page1[kPageSize - 1] = 'z';
page3[0] = 'b';
page3[kPageSize - 1] = 'y';
char buf[kPageSize];
// Completely valid read.
memset(buf, 0xCC, sizeof(buf));
EXPECT_EQ(static_cast<ssize_t>(kPageSize), SafeCopy(buf, page1, kPageSize)) << strerror(errno);
EXPECT_EQ(0, memcmp(buf, page1, kPageSize));
// Reading into a guard page.
memset(buf, 0xCC, sizeof(buf));
EXPECT_EQ(static_cast<ssize_t>(kPageSize - 1), SafeCopy(buf, page1 + 1, kPageSize));
EXPECT_EQ(0, memcmp(buf, page1 + 1, kPageSize - 1));
// Reading from a guard page into a real page.
memset(buf, 0xCC, sizeof(buf));
EXPECT_EQ(0, SafeCopy(buf, page2 + kPageSize - 1, kPageSize));
// Reading off of the end of a mapping.
memset(buf, 0xCC, sizeof(buf));
EXPECT_EQ(static_cast<ssize_t>(kPageSize), SafeCopy(buf, page3, kPageSize * 2));
EXPECT_EQ(0, memcmp(buf, page3, kPageSize));
// Completely invalid.
EXPECT_EQ(0, SafeCopy(buf, page1 + kPageSize, kPageSize));
// Clean up.
ASSERT_EQ(0, munmap(map, kPageSize * 3));
}
TEST(SafeCopyTest, alignment) {
DCHECK_EQ(kPageSize, static_cast<decltype(kPageSize)>(PAGE_SIZE));
// Copy the middle of a mapping to the end of another one.
void* src_map = mmap(nullptr, kPageSize * 3, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
ASSERT_NE(MAP_FAILED, src_map);
// Add a guard page to make sure we don't write past the end of the mapping.
void* dst_map = mmap(nullptr, kPageSize * 4, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
ASSERT_NE(MAP_FAILED, dst_map);
char* src = static_cast<char*>(src_map);
char* dst = static_cast<char*>(dst_map);
ASSERT_EQ(0, mprotect(dst + 3 * kPageSize, kPageSize, PROT_NONE));
src[512] = 'a';
src[kPageSize * 3 - 512 - 1] = 'z';
EXPECT_EQ(static_cast<ssize_t>(kPageSize * 3 - 1024),
SafeCopy(dst + 1024, src + 512, kPageSize * 3 - 1024));
EXPECT_EQ(0, memcmp(dst + 1024, src + 512, kPageSize * 3 - 1024));
ASSERT_EQ(0, munmap(src_map, kPageSize * 3));
ASSERT_EQ(0, munmap(dst_map, kPageSize * 4));
}
#endif // defined(__linux__)
} // namespace art
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