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