diff options
Diffstat (limited to 'test/syscalls/linux/mmap.cc')
| -rw-r--r-- | test/syscalls/linux/mmap.cc | 1685 |
1 files changed, 0 insertions, 1685 deletions
diff --git a/test/syscalls/linux/mmap.cc b/test/syscalls/linux/mmap.cc deleted file mode 100644 index 83546830d..000000000 --- a/test/syscalls/linux/mmap.cc +++ /dev/null @@ -1,1685 +0,0 @@ -// Copyright 2018 The gVisor Authors. -// -// 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 <errno.h> -#include <fcntl.h> -#include <linux/magic.h> -#include <linux/unistd.h> -#include <signal.h> -#include <stdio.h> -#include <stdlib.h> -#include <string.h> -#include <sys/mman.h> -#include <sys/resource.h> -#include <sys/statfs.h> -#include <sys/syscall.h> -#include <sys/time.h> -#include <sys/types.h> -#include <sys/wait.h> -#include <unistd.h> - -#include <vector> - -#include "gmock/gmock.h" -#include "gtest/gtest.h" -#include "absl/strings/escaping.h" -#include "absl/strings/str_split.h" -#include "test/util/cleanup.h" -#include "test/util/file_descriptor.h" -#include "test/util/fs_util.h" -#include "test/util/memory_util.h" -#include "test/util/multiprocess_util.h" -#include "test/util/temp_path.h" -#include "test/util/test_util.h" - -using ::testing::AnyOf; -using ::testing::Eq; -using ::testing::Gt; - -namespace gvisor { -namespace testing { - -namespace { - -PosixErrorOr<int64_t> VirtualMemorySize() { - ASSIGN_OR_RETURN_ERRNO(auto contents, GetContents("/proc/self/statm")); - std::vector<std::string> parts = absl::StrSplit(contents, ' '); - if (parts.empty()) { - return PosixError(EINVAL, "Unable to parse /proc/self/statm"); - } - ASSIGN_OR_RETURN_ERRNO(auto pages, Atoi<int64_t>(parts[0])); - return pages * getpagesize(); -} - -class MMapTest : public ::testing::Test { - protected: - // Unmap mapping, if one was made. - void TearDown() override { - if (addr_) { - EXPECT_THAT(Unmap(), SyscallSucceeds()); - } - } - - // Remembers mapping, so it can be automatically unmapped. - uintptr_t Map(uintptr_t addr, size_t length, int prot, int flags, int fd, - off_t offset) { - void* ret = - mmap(reinterpret_cast<void*>(addr), length, prot, flags, fd, offset); - - if (ret != MAP_FAILED) { - addr_ = ret; - length_ = length; - } - - return reinterpret_cast<uintptr_t>(ret); - } - - // Unmap previous mapping - int Unmap() { - if (!addr_) { - return -1; - } - - int ret = munmap(addr_, length_); - - addr_ = nullptr; - length_ = 0; - - return ret; - } - - // Msync the mapping. - int Msync() { return msync(addr_, length_, MS_SYNC); } - - // Mlock the mapping. - int Mlock() { return mlock(addr_, length_); } - - // Munlock the mapping. - int Munlock() { return munlock(addr_, length_); } - - int Protect(uintptr_t addr, size_t length, int prot) { - return mprotect(reinterpret_cast<void*>(addr), length, prot); - } - - void* addr_ = nullptr; - size_t length_ = 0; -}; - -// Matches if arg contains the same contents as string str. -MATCHER_P(EqualsMemory, str, "") { - if (0 == memcmp(arg, str.c_str(), str.size())) { - return true; - } - - *result_listener << "Memory did not match. Got:\n" - << absl::BytesToHexString( - std::string(static_cast<char*>(arg), str.size())) - << "Want:\n" - << absl::BytesToHexString(str); - return false; -} - -// We can't map pipes, but for different reasons. -TEST_F(MMapTest, MapPipe) { - int fds[2]; - ASSERT_THAT(pipe(fds), SyscallSucceeds()); - EXPECT_THAT(Map(0, kPageSize, PROT_READ, MAP_PRIVATE, fds[0], 0), - SyscallFailsWithErrno(ENODEV)); - EXPECT_THAT(Map(0, kPageSize, PROT_READ, MAP_PRIVATE, fds[1], 0), - SyscallFailsWithErrno(EACCES)); - ASSERT_THAT(close(fds[0]), SyscallSucceeds()); - ASSERT_THAT(close(fds[1]), SyscallSucceeds()); -} - -// It's very common to mmap /dev/zero because anonymous mappings aren't part -// of POSIX although they are widely supported. So a zero initialized memory -// region would actually come from a "file backed" /dev/zero mapping. -TEST_F(MMapTest, MapDevZeroShared) { - // This test will verify that we're able to map a page backed by /dev/zero - // as MAP_SHARED. - const FileDescriptor dev_zero = - ASSERT_NO_ERRNO_AND_VALUE(Open("/dev/zero", O_RDWR)); - - // Test that we can create a RW SHARED mapping of /dev/zero. - ASSERT_THAT( - Map(0, kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED, dev_zero.get(), 0), - SyscallSucceeds()); -} - -TEST_F(MMapTest, MapDevZeroPrivate) { - // This test will verify that we're able to map a page backed by /dev/zero - // as MAP_PRIVATE. - const FileDescriptor dev_zero = - ASSERT_NO_ERRNO_AND_VALUE(Open("/dev/zero", O_RDWR)); - - // Test that we can create a RW SHARED mapping of /dev/zero. - ASSERT_THAT( - Map(0, kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE, dev_zero.get(), 0), - SyscallSucceeds()); -} - -TEST_F(MMapTest, MapDevZeroNoPersistence) { - // This test will verify that two independent mappings of /dev/zero do not - // appear to reference the same "backed file." - - const FileDescriptor dev_zero1 = - ASSERT_NO_ERRNO_AND_VALUE(Open("/dev/zero", O_RDWR)); - const FileDescriptor dev_zero2 = - ASSERT_NO_ERRNO_AND_VALUE(Open("/dev/zero", O_RDWR)); - - ASSERT_THAT( - Map(0, kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED, dev_zero1.get(), 0), - SyscallSucceeds()); - - // Create a second mapping via the second /dev/zero fd. - void* psec_map = mmap(nullptr, kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED, - dev_zero2.get(), 0); - ASSERT_THAT(reinterpret_cast<intptr_t>(psec_map), SyscallSucceeds()); - - // Always unmap. - auto cleanup_psec_map = Cleanup( - [&] { EXPECT_THAT(munmap(psec_map, kPageSize), SyscallSucceeds()); }); - - // Verify that we have independently addressed pages. - ASSERT_NE(psec_map, addr_); - - std::string buf_zero(kPageSize, 0x00); - std::string buf_ones(kPageSize, 0xFF); - - // Verify the first is actually all zeros after mmap. - EXPECT_THAT(addr_, EqualsMemory(buf_zero)); - - // Let's fill in the first mapping with 0xFF. - memcpy(addr_, buf_ones.data(), kPageSize); - - // Verify that the memcpy actually stuck in the page. - EXPECT_THAT(addr_, EqualsMemory(buf_ones)); - - // Verify that it didn't affect the second page which should be all zeros. - EXPECT_THAT(psec_map, EqualsMemory(buf_zero)); -} - -TEST_F(MMapTest, MapDevZeroSharedMultiplePages) { - // This will test that we're able to map /dev/zero over multiple pages. - const FileDescriptor dev_zero = - ASSERT_NO_ERRNO_AND_VALUE(Open("/dev/zero", O_RDWR)); - - // Test that we can create a RW SHARED mapping of /dev/zero. - ASSERT_THAT(Map(0, kPageSize * 2, PROT_READ | PROT_WRITE, MAP_PRIVATE, - dev_zero.get(), 0), - SyscallSucceeds()); - - std::string buf_zero(kPageSize * 2, 0x00); - std::string buf_ones(kPageSize * 2, 0xFF); - - // Verify the two pages are actually all zeros after mmap. - EXPECT_THAT(addr_, EqualsMemory(buf_zero)); - - // Fill out the pages with all ones. - memcpy(addr_, buf_ones.data(), kPageSize * 2); - - // Verify that the memcpy actually stuck in the pages. - EXPECT_THAT(addr_, EqualsMemory(buf_ones)); -} - -TEST_F(MMapTest, MapDevZeroSharedFdNoPersistence) { - // This test will verify that two independent mappings of /dev/zero do not - // appear to reference the same "backed file" even when mapped from the - // same initial fd. - const FileDescriptor dev_zero = - ASSERT_NO_ERRNO_AND_VALUE(Open("/dev/zero", O_RDWR)); - - ASSERT_THAT( - Map(0, kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED, dev_zero.get(), 0), - SyscallSucceeds()); - - // Create a second mapping via the same fd. - void* psec_map = mmap(nullptr, kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED, - dev_zero.get(), 0); - ASSERT_THAT(reinterpret_cast<int64_t>(psec_map), SyscallSucceeds()); - - // Always unmap. - auto cleanup_psec_map = Cleanup( - [&] { ASSERT_THAT(munmap(psec_map, kPageSize), SyscallSucceeds()); }); - - // Verify that we have independently addressed pages. - ASSERT_NE(psec_map, addr_); - - std::string buf_zero(kPageSize, 0x00); - std::string buf_ones(kPageSize, 0xFF); - - // Verify the first is actually all zeros after mmap. - EXPECT_THAT(addr_, EqualsMemory(buf_zero)); - - // Let's fill in the first mapping with 0xFF. - memcpy(addr_, buf_ones.data(), kPageSize); - - // Verify that the memcpy actually stuck in the page. - EXPECT_THAT(addr_, EqualsMemory(buf_ones)); - - // Verify that it didn't affect the second page which should be all zeros. - EXPECT_THAT(psec_map, EqualsMemory(buf_zero)); -} - -TEST_F(MMapTest, MapDevZeroSegfaultAfterUnmap) { - SetupGvisorDeathTest(); - - // This test will verify that we're able to map a page backed by /dev/zero - // as MAP_SHARED and after it's unmapped any access results in a SIGSEGV. - // This test is redundant but given the special nature of /dev/zero mappings - // it doesn't hurt. - const FileDescriptor dev_zero = - ASSERT_NO_ERRNO_AND_VALUE(Open("/dev/zero", O_RDWR)); - - const auto rest = [&] { - // Test that we can create a RW SHARED mapping of /dev/zero. - TEST_PCHECK(Map(0, kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED, - dev_zero.get(), - 0) != reinterpret_cast<uintptr_t>(MAP_FAILED)); - - // Confirm that accesses after the unmap result in a SIGSEGV. - // - // N.B. We depend on this process being single-threaded to ensure there - // can't be another mmap to map addr before the dereference below. - void* addr_saved = addr_; // Unmap resets addr_. - TEST_PCHECK(Unmap() == 0); - *reinterpret_cast<volatile int*>(addr_saved) = 0xFF; - }; - - EXPECT_THAT(InForkedProcess(rest), - IsPosixErrorOkAndHolds(AnyOf(Eq(W_EXITCODE(0, SIGSEGV)), - Eq(W_EXITCODE(0, 128 + SIGSEGV))))); -} - -TEST_F(MMapTest, MapDevZeroUnaligned) { - const FileDescriptor dev_zero = - ASSERT_NO_ERRNO_AND_VALUE(Open("/dev/zero", O_RDWR)); - const size_t size = kPageSize + kPageSize / 2; - const std::string buf_zero(size, 0x00); - - ASSERT_THAT( - Map(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, dev_zero.get(), 0), - SyscallSucceeds()); - EXPECT_THAT(addr_, EqualsMemory(buf_zero)); - ASSERT_THAT(Unmap(), SyscallSucceeds()); - - ASSERT_THAT( - Map(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, dev_zero.get(), 0), - SyscallSucceeds()); - EXPECT_THAT(addr_, EqualsMemory(buf_zero)); -} - -// We can't map _some_ character devices. -TEST_F(MMapTest, MapCharDevice) { - const FileDescriptor cdevfd = - ASSERT_NO_ERRNO_AND_VALUE(Open("/dev/random", 0, 0)); - EXPECT_THAT(Map(0, kPageSize, PROT_READ, MAP_PRIVATE, cdevfd.get(), 0), - SyscallFailsWithErrno(ENODEV)); -} - -// We can't map directories. -TEST_F(MMapTest, MapDirectory) { - const FileDescriptor dirfd = - ASSERT_NO_ERRNO_AND_VALUE(Open(GetAbsoluteTestTmpdir(), 0, 0)); - EXPECT_THAT(Map(0, kPageSize, PROT_READ, MAP_PRIVATE, dirfd.get(), 0), - SyscallFailsWithErrno(ENODEV)); -} - -// We can map *something* -TEST_F(MMapTest, MapAnything) { - EXPECT_THAT(Map(0, kPageSize, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceedsWithValue(Gt(0))); -} - -// Map length < PageSize allowed -TEST_F(MMapTest, SmallMap) { - EXPECT_THAT(Map(0, 128, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceeds()); -} - -// Hint address doesn't break anything. -// Note: there is no requirement we actually get the hint address -TEST_F(MMapTest, HintAddress) { - EXPECT_THAT( - Map(0x30000000, kPageSize, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceeds()); -} - -// MAP_FIXED gives us exactly the requested address -TEST_F(MMapTest, MapFixed) { - EXPECT_THAT(Map(0x30000000, kPageSize, PROT_NONE, - MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0), - SyscallSucceedsWithValue(0x30000000)); -} - -// 64-bit addresses work too -#if defined(__x86_64__) || defined(__aarch64__) -TEST_F(MMapTest, MapFixed64) { - EXPECT_THAT(Map(0x300000000000, kPageSize, PROT_NONE, - MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0), - SyscallSucceedsWithValue(0x300000000000)); -} -#endif - -// MAP_STACK allowed. -// There isn't a good way to verify it did anything. -TEST_F(MMapTest, MapStack) { - EXPECT_THAT(Map(0, kPageSize, PROT_NONE, - MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0), - SyscallSucceeds()); -} - -// MAP_LOCKED allowed. -// There isn't a good way to verify it did anything. -TEST_F(MMapTest, MapLocked) { - EXPECT_THAT(Map(0, kPageSize, PROT_NONE, - MAP_PRIVATE | MAP_ANONYMOUS | MAP_LOCKED, -1, 0), - SyscallSucceeds()); -} - -// MAP_PRIVATE or MAP_SHARED must be passed -TEST_F(MMapTest, NotPrivateOrShared) { - EXPECT_THAT(Map(0, kPageSize, PROT_NONE, MAP_ANONYMOUS, -1, 0), - SyscallFailsWithErrno(EINVAL)); -} - -// Only one of MAP_PRIVATE or MAP_SHARED may be passed -TEST_F(MMapTest, PrivateAndShared) { - EXPECT_THAT(Map(0, kPageSize, PROT_NONE, - MAP_PRIVATE | MAP_SHARED | MAP_ANONYMOUS, -1, 0), - SyscallFailsWithErrno(EINVAL)); -} - -TEST_F(MMapTest, FixedAlignment) { - // Addr must be page aligned (MAP_FIXED) - EXPECT_THAT(Map(0x30000001, kPageSize, PROT_NONE, - MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS, -1, 0), - SyscallFailsWithErrno(EINVAL)); -} - -// Non-MAP_FIXED address does not need to be page aligned -TEST_F(MMapTest, NonFixedAlignment) { - EXPECT_THAT( - Map(0x30000001, kPageSize, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceeds()); -} - -// Length = 0 results in EINVAL. -TEST_F(MMapTest, InvalidLength) { - EXPECT_THAT(Map(0, 0, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallFailsWithErrno(EINVAL)); -} - -// Bad fd not allowed. -TEST_F(MMapTest, BadFd) { - EXPECT_THAT(Map(0, kPageSize, PROT_NONE, MAP_PRIVATE, 999, 0), - SyscallFailsWithErrno(EBADF)); -} - -// Mappings are writable. -TEST_F(MMapTest, ProtWrite) { - uint64_t addr; - constexpr uint8_t kFirstWord[] = {42, 42, 42, 42}; - - EXPECT_THAT(addr = Map(0, kPageSize, PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceeds()); - - // This shouldn't cause a SIGSEGV. - memset(reinterpret_cast<void*>(addr), 42, kPageSize); - - // The written data should actually be there. - EXPECT_EQ( - 0, memcmp(reinterpret_cast<void*>(addr), kFirstWord, sizeof(kFirstWord))); -} - -// "Write-only" mappings are writable *and* readable. -TEST_F(MMapTest, ProtWriteOnly) { - uint64_t addr; - constexpr uint8_t kFirstWord[] = {42, 42, 42, 42}; - - EXPECT_THAT( - addr = Map(0, kPageSize, PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceeds()); - - // This shouldn't cause a SIGSEGV. - memset(reinterpret_cast<void*>(addr), 42, kPageSize); - - // The written data should actually be there. - EXPECT_EQ( - 0, memcmp(reinterpret_cast<void*>(addr), kFirstWord, sizeof(kFirstWord))); -} - -// "Write-only" mappings are readable. -// -// This is distinct from above to ensure the page is accessible even if the -// initial fault is a write fault. -TEST_F(MMapTest, ProtWriteOnlyReadable) { - uint64_t addr; - constexpr uint64_t kFirstWord = 0; - - EXPECT_THAT( - addr = Map(0, kPageSize, PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceeds()); - - EXPECT_EQ(0, memcmp(reinterpret_cast<void*>(addr), &kFirstWord, - sizeof(kFirstWord))); -} - -// Mappings are writable after mprotect from PROT_NONE to PROT_READ|PROT_WRITE. -TEST_F(MMapTest, ProtectProtWrite) { - uint64_t addr; - constexpr uint8_t kFirstWord[] = {42, 42, 42, 42}; - - EXPECT_THAT( - addr = Map(0, kPageSize, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceeds()); - - ASSERT_THAT(Protect(addr, kPageSize, PROT_READ | PROT_WRITE), - SyscallSucceeds()); - - // This shouldn't cause a SIGSEGV. - memset(reinterpret_cast<void*>(addr), 42, kPageSize); - - // The written data should actually be there. - EXPECT_EQ( - 0, memcmp(reinterpret_cast<void*>(addr), kFirstWord, sizeof(kFirstWord))); -} - -// SIGSEGV raised when reading PROT_NONE memory -TEST_F(MMapTest, ProtNoneDeath) { - SetupGvisorDeathTest(); - - uintptr_t addr; - - ASSERT_THAT( - addr = Map(0, kPageSize, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceeds()); - - EXPECT_EXIT(*reinterpret_cast<volatile int*>(addr), - ::testing::KilledBySignal(SIGSEGV), ""); -} - -// SIGSEGV raised when writing PROT_READ only memory -TEST_F(MMapTest, ReadOnlyDeath) { - SetupGvisorDeathTest(); - - uintptr_t addr; - - ASSERT_THAT( - addr = Map(0, kPageSize, PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceeds()); - - EXPECT_EXIT(*reinterpret_cast<volatile int*>(addr) = 42, - ::testing::KilledBySignal(SIGSEGV), ""); -} - -// Writable mapping mprotect'd to read-only should not be writable. -TEST_F(MMapTest, MprotectReadOnlyDeath) { - SetupGvisorDeathTest(); - - uintptr_t addr; - - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceeds()); - - volatile int* val = reinterpret_cast<int*>(addr); - - // Copy to ensure page is mapped in. - *val = 42; - - ASSERT_THAT(Protect(addr, kPageSize, PROT_READ), SyscallSucceeds()); - - // Now it shouldn't be writable. - EXPECT_EXIT(*val = 0, ::testing::KilledBySignal(SIGSEGV), ""); -} - -// Verify that calling mprotect an address that's not page aligned fails. -TEST_F(MMapTest, MprotectNotPageAligned) { - uintptr_t addr; - - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceeds()); - ASSERT_THAT(Protect(addr + 1, kPageSize - 1, PROT_READ), - SyscallFailsWithErrno(EINVAL)); -} - -// Verify that calling mprotect with an absurdly huge length fails. -TEST_F(MMapTest, MprotectHugeLength) { - uintptr_t addr; - - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceeds()); - ASSERT_THAT(Protect(addr, static_cast<size_t>(-1), PROT_READ), - SyscallFailsWithErrno(ENOMEM)); -} - -#if defined(__x86_64__) || defined(__i386__) -// This code is equivalent in 32 and 64-bit mode -const uint8_t machine_code[] = { - 0xb8, 0x2a, 0x00, 0x00, 0x00, // movl $42, %eax - 0xc3, // retq -}; -#elif defined(__aarch64__) -const uint8_t machine_code[] = { - 0x40, 0x05, 0x80, 0x52, // mov w0, #42 - 0xc0, 0x03, 0x5f, 0xd6, // ret -}; -#endif - -// PROT_EXEC allows code execution -TEST_F(MMapTest, ProtExec) { - uintptr_t addr; - uint32_t (*func)(void); - - EXPECT_THAT(addr = Map(0, kPageSize, PROT_EXEC | PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceeds()); - - memcpy(reinterpret_cast<void*>(addr), machine_code, sizeof(machine_code)); - -#if defined(__aarch64__) - // We use this as a memory barrier for Arm64. - ASSERT_THAT(Protect(addr, kPageSize, PROT_READ | PROT_EXEC), - SyscallSucceeds()); -#endif - - func = reinterpret_cast<uint32_t (*)(void)>(addr); - - EXPECT_EQ(42, func()); -} - -// No PROT_EXEC disallows code execution -TEST_F(MMapTest, NoProtExecDeath) { - SetupGvisorDeathTest(); - - uintptr_t addr; - uint32_t (*func)(void); - - EXPECT_THAT(addr = Map(0, kPageSize, PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceeds()); - - memcpy(reinterpret_cast<void*>(addr), machine_code, sizeof(machine_code)); - - func = reinterpret_cast<uint32_t (*)(void)>(addr); - - EXPECT_EXIT(func(), ::testing::KilledBySignal(SIGSEGV), ""); -} - -TEST_F(MMapTest, NoExceedLimitData) { - void* prevbrk; - void* target_brk; - struct rlimit setlim; - - prevbrk = sbrk(0); - ASSERT_NE(-1, reinterpret_cast<intptr_t>(prevbrk)); - target_brk = reinterpret_cast<char*>(prevbrk) + 1; - - setlim.rlim_cur = RLIM_INFINITY; - setlim.rlim_max = RLIM_INFINITY; - ASSERT_THAT(setrlimit(RLIMIT_DATA, &setlim), SyscallSucceeds()); - EXPECT_THAT(brk(target_brk), SyscallSucceedsWithValue(0)); -} - -TEST_F(MMapTest, ExceedLimitData) { - // To unit test this more precisely, we'd need access to the mm's start_brk - // and end_brk, which we don't have direct access to :/ - void* prevbrk; - void* target_brk; - struct rlimit setlim; - - prevbrk = sbrk(0); - ASSERT_NE(-1, reinterpret_cast<intptr_t>(prevbrk)); - target_brk = reinterpret_cast<char*>(prevbrk) + 8192; - - setlim.rlim_cur = 0; - setlim.rlim_max = RLIM_INFINITY; - // Set RLIMIT_DATA very low so any subsequent brk() calls fail. - // Reset RLIMIT_DATA during teardown step. - ASSERT_THAT(setrlimit(RLIMIT_DATA, &setlim), SyscallSucceeds()); - EXPECT_THAT(brk(target_brk), SyscallFailsWithErrno(ENOMEM)); - // Teardown step... - setlim.rlim_cur = RLIM_INFINITY; - ASSERT_THAT(setrlimit(RLIMIT_DATA, &setlim), SyscallSucceeds()); -} - -TEST_F(MMapTest, ExceedLimitDataPrlimit) { - // To unit test this more precisely, we'd need access to the mm's start_brk - // and end_brk, which we don't have direct access to :/ - void* prevbrk; - void* target_brk; - struct rlimit setlim; - - prevbrk = sbrk(0); - ASSERT_NE(-1, reinterpret_cast<intptr_t>(prevbrk)); - target_brk = reinterpret_cast<char*>(prevbrk) + 8192; - - setlim.rlim_cur = 0; - setlim.rlim_max = RLIM_INFINITY; - // Set RLIMIT_DATA very low so any subsequent brk() calls fail. - // Reset RLIMIT_DATA during teardown step. - ASSERT_THAT(prlimit(0, RLIMIT_DATA, &setlim, nullptr), SyscallSucceeds()); - EXPECT_THAT(brk(target_brk), SyscallFailsWithErrno(ENOMEM)); - // Teardown step... - setlim.rlim_cur = RLIM_INFINITY; - ASSERT_THAT(setrlimit(RLIMIT_DATA, &setlim), SyscallSucceeds()); -} - -TEST_F(MMapTest, ExceedLimitDataPrlimitPID) { - // To unit test this more precisely, we'd need access to the mm's start_brk - // and end_brk, which we don't have direct access to :/ - void* prevbrk; - void* target_brk; - struct rlimit setlim; - - prevbrk = sbrk(0); - ASSERT_NE(-1, reinterpret_cast<intptr_t>(prevbrk)); - target_brk = reinterpret_cast<char*>(prevbrk) + 8192; - - setlim.rlim_cur = 0; - setlim.rlim_max = RLIM_INFINITY; - // Set RLIMIT_DATA very low so any subsequent brk() calls fail. - // Reset RLIMIT_DATA during teardown step. - ASSERT_THAT(prlimit(syscall(__NR_gettid), RLIMIT_DATA, &setlim, nullptr), - SyscallSucceeds()); - EXPECT_THAT(brk(target_brk), SyscallFailsWithErrno(ENOMEM)); - // Teardown step... - setlim.rlim_cur = RLIM_INFINITY; - ASSERT_THAT(setrlimit(RLIMIT_DATA, &setlim), SyscallSucceeds()); -} - -TEST_F(MMapTest, NoExceedLimitAS) { - constexpr uint64_t kAllocBytes = 200 << 20; - // Add some headroom to the AS limit in case of e.g. unexpected stack - // expansion. - constexpr uint64_t kExtraASBytes = kAllocBytes + (20 << 20); - static_assert(kAllocBytes < kExtraASBytes, - "test depends on allocation not exceeding AS limit"); - - auto vss = ASSERT_NO_ERRNO_AND_VALUE(VirtualMemorySize()); - struct rlimit setlim; - setlim.rlim_cur = vss + kExtraASBytes; - setlim.rlim_max = RLIM_INFINITY; - ASSERT_THAT(setrlimit(RLIMIT_AS, &setlim), SyscallSucceeds()); - EXPECT_THAT( - Map(0, kAllocBytes, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceedsWithValue(Gt(0))); -} - -TEST_F(MMapTest, ExceedLimitAS) { - constexpr uint64_t kAllocBytes = 200 << 20; - // Add some headroom to the AS limit in case of e.g. unexpected stack - // expansion. - constexpr uint64_t kExtraASBytes = 20 << 20; - static_assert(kAllocBytes > kExtraASBytes, - "test depends on allocation exceeding AS limit"); - - auto vss = ASSERT_NO_ERRNO_AND_VALUE(VirtualMemorySize()); - struct rlimit setlim; - setlim.rlim_cur = vss + kExtraASBytes; - setlim.rlim_max = RLIM_INFINITY; - ASSERT_THAT(setrlimit(RLIMIT_AS, &setlim), SyscallSucceeds()); - EXPECT_THAT( - Map(0, kAllocBytes, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallFailsWithErrno(ENOMEM)); -} - -// Tests that setting an anonymous mmap to PROT_NONE doesn't free the memory. -TEST_F(MMapTest, SettingProtNoneDoesntFreeMemory) { - uintptr_t addr; - constexpr uint8_t kFirstWord[] = {42, 42, 42, 42}; - - EXPECT_THAT(addr = Map(0, kPageSize, PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceedsWithValue(Gt(0))); - - memset(reinterpret_cast<void*>(addr), 42, kPageSize); - - ASSERT_THAT(Protect(addr, kPageSize, PROT_NONE), SyscallSucceeds()); - ASSERT_THAT(Protect(addr, kPageSize, PROT_READ | PROT_WRITE), - SyscallSucceeds()); - - // The written data should still be there. - EXPECT_EQ( - 0, memcmp(reinterpret_cast<void*>(addr), kFirstWord, sizeof(kFirstWord))); -} - -constexpr char kFileContents[] = "Hello World!"; - -class MMapFileTest : public MMapTest { - protected: - FileDescriptor fd_; - std::string filename_; - - // Open a file for read/write - void SetUp() override { - MMapTest::SetUp(); - - filename_ = NewTempAbsPath(); - fd_ = ASSERT_NO_ERRNO_AND_VALUE(Open(filename_, O_CREAT | O_RDWR, 0644)); - - // Extend file so it can be written once mapped. Deliberately make the file - // only half a page in size, so we can test what happens when we access the - // second half. - // Use ftruncate(2) once the sentry supports it. - char zero = 0; - size_t count = 0; - do { - const DisableSave ds; // saving 2048 times is slow and useless. - Write(&zero, 1), SyscallSucceedsWithValue(1); - } while (++count < (kPageSize / 2)); - ASSERT_THAT(lseek(fd_.get(), 0, SEEK_SET), SyscallSucceedsWithValue(0)); - } - - // Close and delete file - void TearDown() override { - MMapTest::TearDown(); - fd_.reset(); // Make sure the files is closed before we unlink it. - ASSERT_THAT(unlink(filename_.c_str()), SyscallSucceeds()); - } - - ssize_t Read(char* buf, size_t count) { - ssize_t len = 0; - do { - ssize_t ret = read(fd_.get(), buf, count); - if (ret < 0) { - return ret; - } else if (ret == 0) { - return len; - } - - len += ret; - buf += ret; - } while (len < static_cast<ssize_t>(count)); - - return len; - } - - ssize_t Write(const char* buf, size_t count) { - ssize_t len = 0; - do { - ssize_t ret = write(fd_.get(), buf, count); - if (ret < 0) { - return ret; - } else if (ret == 0) { - return len; - } - - len += ret; - buf += ret; - } while (len < static_cast<ssize_t>(count)); - - return len; - } -}; - -class MMapFileParamTest - : public MMapFileTest, - public ::testing::WithParamInterface<std::tuple<int, int>> { - protected: - int prot() const { return std::get<0>(GetParam()); } - - int flags() const { return std::get<1>(GetParam()); } -}; - -// MAP_POPULATE allowed. -// There isn't a good way to verify it actually did anything. -TEST_P(MMapFileParamTest, MapPopulate) { - ASSERT_THAT(Map(0, kPageSize, prot(), flags() | MAP_POPULATE, fd_.get(), 0), - SyscallSucceeds()); -} - -// MAP_POPULATE on a short file. -TEST_P(MMapFileParamTest, MapPopulateShort) { - ASSERT_THAT( - Map(0, 2 * kPageSize, prot(), flags() | MAP_POPULATE, fd_.get(), 0), - SyscallSucceeds()); -} - -// Read contents from mapped file. -TEST_F(MMapFileTest, Read) { - size_t len = strlen(kFileContents); - ASSERT_EQ(len, Write(kFileContents, len)); - - uintptr_t addr; - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ, MAP_PRIVATE, fd_.get(), 0), - SyscallSucceeds()); - - EXPECT_THAT(reinterpret_cast<char*>(addr), - EqualsMemory(std::string(kFileContents))); -} - -// Map at an offset. -TEST_F(MMapFileTest, MapOffset) { - ASSERT_THAT(lseek(fd_.get(), kPageSize, SEEK_SET), SyscallSucceeds()); - - size_t len = strlen(kFileContents); - ASSERT_EQ(len, Write(kFileContents, len)); - - uintptr_t addr; - ASSERT_THAT( - addr = Map(0, kPageSize, PROT_READ, MAP_PRIVATE, fd_.get(), kPageSize), - SyscallSucceeds()); - - EXPECT_THAT(reinterpret_cast<char*>(addr), - EqualsMemory(std::string(kFileContents))); -} - -TEST_F(MMapFileTest, MapOffsetBeyondEnd) { - SetupGvisorDeathTest(); - - uintptr_t addr; - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE, - fd_.get(), 10 * kPageSize), - SyscallSucceeds()); - - // Touching the memory causes SIGBUS. - size_t len = strlen(kFileContents); - EXPECT_EXIT(std::copy(kFileContents, kFileContents + len, - reinterpret_cast<volatile char*>(addr)), - ::testing::KilledBySignal(SIGBUS), ""); -} - -// Verify mmap fails when sum of length and offset overflows. -TEST_F(MMapFileTest, MapLengthPlusOffsetOverflows) { - const size_t length = static_cast<size_t>(-kPageSize); - const off_t offset = kPageSize; - ASSERT_THAT(Map(0, length, PROT_READ, MAP_PRIVATE, fd_.get(), offset), - SyscallFailsWithErrno(ENOMEM)); -} - -// MAP_PRIVATE PROT_WRITE is allowed on read-only FDs. -TEST_F(MMapFileTest, WritePrivateOnReadOnlyFd) { - const FileDescriptor fd = - ASSERT_NO_ERRNO_AND_VALUE(Open(filename_, O_RDONLY)); - - uintptr_t addr; - EXPECT_THAT(addr = Map(0, kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE, - fd.get(), 0), - SyscallSucceeds()); - - // Touch the page to ensure the kernel didn't lie about writability. - size_t len = strlen(kFileContents); - std::copy(kFileContents, kFileContents + len, - reinterpret_cast<volatile char*>(addr)); -} - -// MAP_SHARED PROT_WRITE not allowed on read-only FDs. -TEST_F(MMapFileTest, WriteSharedOnReadOnlyFd) { - const FileDescriptor fd = - ASSERT_NO_ERRNO_AND_VALUE(Open(filename_, O_RDONLY)); - - uintptr_t addr; - EXPECT_THAT( - addr = Map(0, kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED, fd.get(), 0), - SyscallFailsWithErrno(EACCES)); -} - -// The FD must be readable. -TEST_P(MMapFileParamTest, WriteOnlyFd) { - const FileDescriptor fd = - ASSERT_NO_ERRNO_AND_VALUE(Open(filename_, O_WRONLY)); - - uintptr_t addr; - EXPECT_THAT(addr = Map(0, kPageSize, prot(), flags(), fd.get(), 0), - SyscallFailsWithErrno(EACCES)); -} - -// Overwriting the contents of a file mapped MAP_SHARED PROT_READ -// should cause the new data to be reflected in the mapping. -TEST_F(MMapFileTest, ReadSharedConsistentWithOverwrite) { - // Start from scratch. - EXPECT_THAT(ftruncate(fd_.get(), 0), SyscallSucceeds()); - - // Expand the file to two pages and dirty them. - std::string bufA(kPageSize, 'a'); - ASSERT_THAT(Write(bufA.c_str(), bufA.size()), - SyscallSucceedsWithValue(bufA.size())); - std::string bufB(kPageSize, 'b'); - ASSERT_THAT(Write(bufB.c_str(), bufB.size()), - SyscallSucceedsWithValue(bufB.size())); - - // Map the page. - uintptr_t addr; - ASSERT_THAT(addr = Map(0, 2 * kPageSize, PROT_READ, MAP_SHARED, fd_.get(), 0), - SyscallSucceeds()); - - // Check that the mapping contains the right file data. - EXPECT_EQ(0, memcmp(reinterpret_cast<void*>(addr), bufA.c_str(), kPageSize)); - EXPECT_EQ(0, memcmp(reinterpret_cast<void*>(addr + kPageSize), bufB.c_str(), - kPageSize)); - - // Start at the beginning of the file. - ASSERT_THAT(lseek(fd_.get(), 0, SEEK_SET), SyscallSucceedsWithValue(0)); - - // Swap the write pattern. - ASSERT_THAT(Write(bufB.c_str(), bufB.size()), - SyscallSucceedsWithValue(bufB.size())); - ASSERT_THAT(Write(bufA.c_str(), bufA.size()), - SyscallSucceedsWithValue(bufA.size())); - - // Check that the mapping got updated. - EXPECT_EQ(0, memcmp(reinterpret_cast<void*>(addr), bufB.c_str(), kPageSize)); - EXPECT_EQ(0, memcmp(reinterpret_cast<void*>(addr + kPageSize), bufA.c_str(), - kPageSize)); -} - -// Partially overwriting a file mapped MAP_SHARED PROT_READ should be reflected -// in the mapping. -TEST_F(MMapFileTest, ReadSharedConsistentWithPartialOverwrite) { - // Start from scratch. - EXPECT_THAT(ftruncate(fd_.get(), 0), SyscallSucceeds()); - - // Expand the file to two pages and dirty them. - std::string bufA(kPageSize, 'a'); - ASSERT_THAT(Write(bufA.c_str(), bufA.size()), - SyscallSucceedsWithValue(bufA.size())); - std::string bufB(kPageSize, 'b'); - ASSERT_THAT(Write(bufB.c_str(), bufB.size()), - SyscallSucceedsWithValue(bufB.size())); - - // Map the page. - uintptr_t addr; - ASSERT_THAT(addr = Map(0, 2 * kPageSize, PROT_READ, MAP_SHARED, fd_.get(), 0), - SyscallSucceeds()); - - // Check that the mapping contains the right file data. - EXPECT_EQ(0, memcmp(reinterpret_cast<void*>(addr), bufA.c_str(), kPageSize)); - EXPECT_EQ(0, memcmp(reinterpret_cast<void*>(addr + kPageSize), bufB.c_str(), - kPageSize)); - - // Start at the beginning of the file. - ASSERT_THAT(lseek(fd_.get(), 0, SEEK_SET), SyscallSucceedsWithValue(0)); - - // Do a partial overwrite, spanning both pages. - std::string bufC(kPageSize + (kPageSize / 2), 'c'); - ASSERT_THAT(Write(bufC.c_str(), bufC.size()), - SyscallSucceedsWithValue(bufC.size())); - - // Check that the mapping got updated. - EXPECT_EQ(0, memcmp(reinterpret_cast<void*>(addr), bufC.c_str(), - kPageSize + (kPageSize / 2))); - EXPECT_EQ(0, - memcmp(reinterpret_cast<void*>(addr + kPageSize + (kPageSize / 2)), - bufB.c_str(), kPageSize / 2)); -} - -// Overwriting a file mapped MAP_SHARED PROT_READ should be reflected in the -// mapping and the file. -TEST_F(MMapFileTest, ReadSharedConsistentWithWriteAndFile) { - // Start from scratch. - EXPECT_THAT(ftruncate(fd_.get(), 0), SyscallSucceeds()); - - // Expand the file to two full pages and dirty it. - std::string bufA(2 * kPageSize, 'a'); - ASSERT_THAT(Write(bufA.c_str(), bufA.size()), - SyscallSucceedsWithValue(bufA.size())); - - // Map only the first page. - uintptr_t addr; - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ, MAP_SHARED, fd_.get(), 0), - SyscallSucceeds()); - - // Prepare to overwrite the file contents. - ASSERT_THAT(lseek(fd_.get(), 0, SEEK_SET), SyscallSucceedsWithValue(0)); - - // Overwrite everything, beyond the mapped portion. - std::string bufB(2 * kPageSize, 'b'); - ASSERT_THAT(Write(bufB.c_str(), bufB.size()), - SyscallSucceedsWithValue(bufB.size())); - - // What the mapped portion should now look like. - std::string bufMapped(kPageSize, 'b'); - - // Expect that the mapped portion is consistent. - EXPECT_EQ( - 0, memcmp(reinterpret_cast<void*>(addr), bufMapped.c_str(), kPageSize)); - - // Prepare to read the entire file contents. - ASSERT_THAT(lseek(fd_.get(), 0, SEEK_SET), SyscallSucceedsWithValue(0)); - - // Expect that the file was fully updated. - std::vector<char> bufFile(2 * kPageSize); - ASSERT_THAT(Read(bufFile.data(), bufFile.size()), - SyscallSucceedsWithValue(bufFile.size())); - // Cast to void* to avoid EXPECT_THAT assuming bufFile.data() is a - // NUL-terminated C std::string. EXPECT_THAT will try to print a char* as a C - // std::string, possibly overruning the buffer. - EXPECT_THAT(reinterpret_cast<void*>(bufFile.data()), EqualsMemory(bufB)); -} - -// Write data to mapped file. -TEST_F(MMapFileTest, WriteShared) { - uintptr_t addr; - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED, - fd_.get(), 0), - SyscallSucceeds()); - - size_t len = strlen(kFileContents); - memcpy(reinterpret_cast<void*>(addr), kFileContents, len); - - // The file may not actually be updated until munmap is called. - ASSERT_THAT(Unmap(), SyscallSucceeds()); - - std::vector<char> buf(len); - ASSERT_THAT(Read(buf.data(), buf.size()), - SyscallSucceedsWithValue(buf.size())); - // Cast to void* to avoid EXPECT_THAT assuming buf.data() is a - // NUL-terminated C string. EXPECT_THAT will try to print a char* as a C - // string, possibly overruning the buffer. - EXPECT_THAT(reinterpret_cast<void*>(buf.data()), - EqualsMemory(std::string(kFileContents))); -} - -// Write data to portion of mapped page beyond the end of the file. -// These writes are not reflected in the file. -TEST_F(MMapFileTest, WriteSharedBeyondEnd) { - // The file is only half of a page. We map an entire page. Writes to the - // end of the mapping must not be reflected in the file. - uintptr_t addr; - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED, - fd_.get(), 0), - SyscallSucceeds()); - - // First half; this is reflected in the file. - std::string first(kPageSize / 2, 'A'); - memcpy(reinterpret_cast<void*>(addr), first.c_str(), first.size()); - - // Second half; this is not reflected in the file. - std::string second(kPageSize / 2, 'B'); - memcpy(reinterpret_cast<void*>(addr + kPageSize / 2), second.c_str(), - second.size()); - - // The file may not actually be updated until munmap is called. - ASSERT_THAT(Unmap(), SyscallSucceeds()); - - // Big enough to fit the entire page, if the writes are mistakenly written to - // the file. - std::vector<char> buf(kPageSize); - - // Only the first half is in the file. - ASSERT_THAT(Read(buf.data(), buf.size()), - SyscallSucceedsWithValue(first.size())); - // Cast to void* to avoid EXPECT_THAT assuming buf.data() is a - // NUL-terminated C string. EXPECT_THAT will try to print a char* as a C - // NUL-terminated C std::string. EXPECT_THAT will try to print a char* as a C - // std::string, possibly overruning the buffer. - EXPECT_THAT(reinterpret_cast<void*>(buf.data()), EqualsMemory(first)); -} - -// The portion of a mapped page that becomes part of the file after a truncate -// is reflected in the file. -TEST_F(MMapFileTest, WriteSharedTruncateUp) { - // The file is only half of a page. We map an entire page. Writes to the - // end of the mapping must not be reflected in the file. - uintptr_t addr; - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED, - fd_.get(), 0), - SyscallSucceeds()); - - // First half; this is reflected in the file. - std::string first(kPageSize / 2, 'A'); - memcpy(reinterpret_cast<void*>(addr), first.c_str(), first.size()); - - // Second half; this is not reflected in the file now (see - // WriteSharedBeyondEnd), but will be after the truncate. - std::string second(kPageSize / 2, 'B'); - memcpy(reinterpret_cast<void*>(addr + kPageSize / 2), second.c_str(), - second.size()); - - // Extend the file to a full page. The second half of the page will be - // reflected in the file. - EXPECT_THAT(ftruncate(fd_.get(), kPageSize), SyscallSucceeds()); - - // The file may not actually be updated until munmap is called. - ASSERT_THAT(Unmap(), SyscallSucceeds()); - - // The whole page is in the file. - std::vector<char> buf(kPageSize); - ASSERT_THAT(Read(buf.data(), buf.size()), - SyscallSucceedsWithValue(buf.size())); - // Cast to void* to avoid EXPECT_THAT assuming buf.data() is a - // NUL-terminated C string. EXPECT_THAT will try to print a char* as a C - // string, possibly overruning the buffer. - EXPECT_THAT(reinterpret_cast<void*>(buf.data()), EqualsMemory(first)); - EXPECT_THAT(reinterpret_cast<void*>(buf.data() + kPageSize / 2), - EqualsMemory(second)); -} - -TEST_F(MMapFileTest, ReadSharedTruncateDownThenUp) { - // Start from scratch. - EXPECT_THAT(ftruncate(fd_.get(), 0), SyscallSucceeds()); - - // Expand the file to a full page and dirty it. - std::string buf(kPageSize, 'a'); - ASSERT_THAT(Write(buf.c_str(), buf.size()), - SyscallSucceedsWithValue(buf.size())); - - // Map the page. - uintptr_t addr; - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ, MAP_SHARED, fd_.get(), 0), - SyscallSucceeds()); - - // Check that the memory contains the file data. - EXPECT_EQ(0, memcmp(reinterpret_cast<void*>(addr), buf.c_str(), kPageSize)); - - // Truncate down, then up. - EXPECT_THAT(ftruncate(fd_.get(), 0), SyscallSucceeds()); - EXPECT_THAT(ftruncate(fd_.get(), kPageSize), SyscallSucceeds()); - - // Check that the memory was zeroed. - std::string zeroed(kPageSize, '\0'); - EXPECT_EQ(0, - memcmp(reinterpret_cast<void*>(addr), zeroed.c_str(), kPageSize)); - - // The file may not actually be updated until msync is called. - ASSERT_THAT(Msync(), SyscallSucceeds()); - - // Prepare to read the entire file contents. - ASSERT_THAT(lseek(fd_.get(), 0, SEEK_SET), SyscallSucceedsWithValue(0)); - - // Expect that the file is fully updated. - std::vector<char> bufFile(kPageSize); - ASSERT_THAT(Read(bufFile.data(), bufFile.size()), - SyscallSucceedsWithValue(bufFile.size())); - EXPECT_EQ(0, memcmp(bufFile.data(), zeroed.c_str(), kPageSize)); -} - -TEST_F(MMapFileTest, WriteSharedTruncateDownThenUp) { - // The file is only half of a page. We map an entire page. Writes to the - // end of the mapping must not be reflected in the file. - uintptr_t addr; - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED, - fd_.get(), 0), - SyscallSucceeds()); - - // First half; this will be deleted by truncate(0). - std::string first(kPageSize / 2, 'A'); - memcpy(reinterpret_cast<void*>(addr), first.c_str(), first.size()); - - // Truncate down, then up. - EXPECT_THAT(ftruncate(fd_.get(), 0), SyscallSucceeds()); - EXPECT_THAT(ftruncate(fd_.get(), kPageSize), SyscallSucceeds()); - - // The whole page is zeroed in memory. - std::string zeroed(kPageSize, '\0'); - EXPECT_EQ(0, - memcmp(reinterpret_cast<void*>(addr), zeroed.c_str(), kPageSize)); - - // The file may not actually be updated until munmap is called. - ASSERT_THAT(Unmap(), SyscallSucceeds()); - - // The whole file is also zeroed. - std::vector<char> buf(kPageSize); - ASSERT_THAT(Read(buf.data(), buf.size()), - SyscallSucceedsWithValue(buf.size())); - // Cast to void* to avoid EXPECT_THAT assuming buf.data() is a - // NUL-terminated C string. EXPECT_THAT will try to print a char* as a C - // string, possibly overruning the buffer. - EXPECT_THAT(reinterpret_cast<void*>(buf.data()), EqualsMemory(zeroed)); -} - -TEST_F(MMapFileTest, ReadSharedTruncateSIGBUS) { - SetupGvisorDeathTest(); - - // Start from scratch. - EXPECT_THAT(ftruncate(fd_.get(), 0), SyscallSucceeds()); - - // Expand the file to a full page and dirty it. - std::string buf(kPageSize, 'a'); - ASSERT_THAT(Write(buf.c_str(), buf.size()), - SyscallSucceedsWithValue(buf.size())); - - // Map the page. - uintptr_t addr; - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ, MAP_SHARED, fd_.get(), 0), - SyscallSucceeds()); - - // Check that the mapping contains the file data. - EXPECT_EQ(0, memcmp(reinterpret_cast<void*>(addr), buf.c_str(), kPageSize)); - - // Truncate down. - EXPECT_THAT(ftruncate(fd_.get(), 0), SyscallSucceeds()); - - // Accessing the truncated region should cause a SIGBUS. - std::vector<char> in(kPageSize); - EXPECT_EXIT( - std::copy(reinterpret_cast<volatile char*>(addr), - reinterpret_cast<volatile char*>(addr) + kPageSize, in.data()), - ::testing::KilledBySignal(SIGBUS), ""); -} - -TEST_F(MMapFileTest, WriteSharedTruncateSIGBUS) { - SetupGvisorDeathTest(); - - uintptr_t addr; - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED, - fd_.get(), 0), - SyscallSucceeds()); - - // Touch the memory to be sure it really is mapped. - size_t len = strlen(kFileContents); - memcpy(reinterpret_cast<void*>(addr), kFileContents, len); - - // Truncate down. - EXPECT_THAT(ftruncate(fd_.get(), 0), SyscallSucceeds()); - - // Accessing the truncated file should cause a SIGBUS. - EXPECT_EXIT(std::copy(kFileContents, kFileContents + len, - reinterpret_cast<volatile char*>(addr)), - ::testing::KilledBySignal(SIGBUS), ""); -} - -TEST_F(MMapFileTest, ReadSharedTruncatePartialPage) { - // Start from scratch. - EXPECT_THAT(ftruncate(fd_.get(), 0), SyscallSucceeds()); - - // Dirty the file. - std::string buf(kPageSize, 'a'); - ASSERT_THAT(Write(buf.c_str(), buf.size()), - SyscallSucceedsWithValue(buf.size())); - - // Map a page. - uintptr_t addr; - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ, MAP_SHARED, fd_.get(), 0), - SyscallSucceeds()); - - // Truncate to half of the page. - EXPECT_THAT(ftruncate(fd_.get(), kPageSize / 2), SyscallSucceeds()); - - // First half of the page untouched. - EXPECT_EQ(0, - memcmp(reinterpret_cast<void*>(addr), buf.data(), kPageSize / 2)); - - // Second half is zeroed. - std::string zeroed(kPageSize / 2, '\0'); - EXPECT_EQ(0, memcmp(reinterpret_cast<void*>(addr + kPageSize / 2), - zeroed.c_str(), kPageSize / 2)); -} - -// Page can still be accessed and contents are intact after truncating a partial -// page. -TEST_F(MMapFileTest, WriteSharedTruncatePartialPage) { - // Expand the file to a full page. - EXPECT_THAT(ftruncate(fd_.get(), kPageSize), SyscallSucceeds()); - - uintptr_t addr; - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED, - fd_.get(), 0), - SyscallSucceeds()); - - // Fill the entire page. - std::string contents(kPageSize, 'A'); - memcpy(reinterpret_cast<void*>(addr), contents.c_str(), contents.size()); - - // Truncate half of the page. - EXPECT_THAT(ftruncate(fd_.get(), kPageSize / 2), SyscallSucceeds()); - - // First half of the page untouched. - EXPECT_EQ(0, memcmp(reinterpret_cast<void*>(addr), contents.c_str(), - kPageSize / 2)); - - // Second half zeroed. - std::string zeroed(kPageSize / 2, '\0'); - EXPECT_EQ(0, memcmp(reinterpret_cast<void*>(addr + kPageSize / 2), - zeroed.c_str(), kPageSize / 2)); -} - -// MAP_PRIVATE writes are not carried through to the underlying file. -TEST_F(MMapFileTest, WritePrivate) { - uintptr_t addr; - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE, - fd_.get(), 0), - SyscallSucceeds()); - - size_t len = strlen(kFileContents); - memcpy(reinterpret_cast<void*>(addr), kFileContents, len); - - // The file should not be updated, but if it mistakenly is, it may not be - // until after munmap is called. - ASSERT_THAT(Unmap(), SyscallSucceeds()); - - std::vector<char> buf(len); - ASSERT_THAT(Read(buf.data(), buf.size()), - SyscallSucceedsWithValue(buf.size())); - // Cast to void* to avoid EXPECT_THAT assuming buf.data() is a - // NUL-terminated C string. EXPECT_THAT will try to print a char* as a C - // string, possibly overruning the buffer. - EXPECT_THAT(reinterpret_cast<void*>(buf.data()), - EqualsMemory(std::string(len, '\0'))); -} - -// SIGBUS raised when reading or writing past end of a mapped file. -TEST_P(MMapFileParamTest, SigBusDeath) { - SetupGvisorDeathTest(); - - uintptr_t addr; - ASSERT_THAT(addr = Map(0, 2 * kPageSize, prot(), flags(), fd_.get(), 0), - SyscallSucceeds()); - - auto* start = reinterpret_cast<volatile char*>(addr + kPageSize); - - // MMapFileTest makes a file kPageSize/2 long. The entire first page should be - // accessible, but anything beyond it should not. - if (prot() & PROT_WRITE) { - // Write beyond first page. - size_t len = strlen(kFileContents); - EXPECT_EXIT(std::copy(kFileContents, kFileContents + len, start), - ::testing::KilledBySignal(SIGBUS), ""); - } else { - // Read beyond first page. - std::vector<char> in(kPageSize); - EXPECT_EXIT(std::copy(start, start + kPageSize, in.data()), - ::testing::KilledBySignal(SIGBUS), ""); - } -} - -// Tests that SIGBUS is not raised when reading or writing to a file-mapped -// page before EOF, even if part of the mapping extends beyond EOF. -// -// See b/27877699. -TEST_P(MMapFileParamTest, NoSigBusOnPagesBeforeEOF) { - uintptr_t addr; - ASSERT_THAT(addr = Map(0, 2 * kPageSize, prot(), flags(), fd_.get(), 0), - SyscallSucceeds()); - - // The test passes if this survives. - auto* start = reinterpret_cast<volatile char*>(addr + (kPageSize / 2) + 1); - size_t len = strlen(kFileContents); - if (prot() & PROT_WRITE) { - std::copy(kFileContents, kFileContents + len, start); - } else { - std::vector<char> in(len); - std::copy(start, start + len, in.data()); - } -} - -// Tests that SIGBUS is not raised when reading or writing from a file-mapped -// page containing EOF, *after* the EOF. -TEST_P(MMapFileParamTest, NoSigBusOnPageContainingEOF) { - uintptr_t addr; - ASSERT_THAT(addr = Map(0, 2 * kPageSize, prot(), flags(), fd_.get(), 0), - SyscallSucceeds()); - - // The test passes if this survives. (Technically addr+kPageSize/2 is already - // beyond EOF, but +1 to check for fencepost errors.) - auto* start = reinterpret_cast<volatile char*>(addr + (kPageSize / 2) + 1); - size_t len = strlen(kFileContents); - if (prot() & PROT_WRITE) { - std::copy(kFileContents, kFileContents + len, start); - } else { - std::vector<char> in(len); - std::copy(start, start + len, in.data()); - } -} - -// Tests that reading from writable shared file-mapped pages succeeds. -// -// On most platforms this is trivial, but when the file is mapped via the sentry -// page cache (which does not yet support writing to shared mappings), a bug -// caused reads to fail unnecessarily on such mappings. See b/28913513. -TEST_F(MMapFileTest, ReadingWritableSharedFilePageSucceeds) { - uintptr_t addr; - size_t len = strlen(kFileContents); - - ASSERT_THAT(addr = Map(0, 2 * kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED, - fd_.get(), 0), - SyscallSucceeds()); - - std::vector<char> buf(kPageSize); - // The test passes if this survives. - std::copy(reinterpret_cast<volatile char*>(addr), - reinterpret_cast<volatile char*>(addr) + len, buf.data()); -} - -// Tests that EFAULT is returned when invoking a syscall that requires the OS to -// read past end of file (resulting in a fault in sentry context in the gVisor -// case). See b/28913513. -TEST_F(MMapFileTest, InternalSigBus) { - uintptr_t addr; - ASSERT_THAT(addr = Map(0, 2 * kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE, - fd_.get(), 0), - SyscallSucceeds()); - - // This depends on the fact that gVisor implements pipes internally. - int pipefd[2]; - ASSERT_THAT(pipe(pipefd), SyscallSucceeds()); - EXPECT_THAT( - write(pipefd[1], reinterpret_cast<void*>(addr + kPageSize), kPageSize), - SyscallFailsWithErrno(EFAULT)); - - EXPECT_THAT(close(pipefd[0]), SyscallSucceeds()); - EXPECT_THAT(close(pipefd[1]), SyscallSucceeds()); -} - -// Like InternalSigBus, but test the WriteZerosAt path by reading from -// /dev/zero to a shared mapping (so that the SIGBUS isn't caught during -// copy-on-write breaking). -TEST_F(MMapFileTest, InternalSigBusZeroing) { - uintptr_t addr; - ASSERT_THAT(addr = Map(0, 2 * kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED, - fd_.get(), 0), - SyscallSucceeds()); - - const FileDescriptor dev_zero = - ASSERT_NO_ERRNO_AND_VALUE(Open("/dev/zero", O_RDONLY)); - EXPECT_THAT(read(dev_zero.get(), reinterpret_cast<void*>(addr + kPageSize), - kPageSize), - SyscallFailsWithErrno(EFAULT)); -} - -// Checks that mmaps with a length of uint64_t(-PAGE_SIZE + 1) or greater do not -// induce a sentry panic (due to "rounding up" to 0). -TEST_F(MMapTest, HugeLength) { - EXPECT_THAT(Map(0, static_cast<uint64_t>(-kPageSize + 1), PROT_NONE, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallFailsWithErrno(ENOMEM)); -} - -// Tests for a specific gVisor MM caching bug. -TEST_F(MMapTest, AccessCOWInvalidatesCachedSegments) { - auto f = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); - auto fd = ASSERT_NO_ERRNO_AND_VALUE(Open(f.path(), O_RDWR)); - auto zero_fd = ASSERT_NO_ERRNO_AND_VALUE(Open("/dev/zero", O_RDONLY)); - - // Get a two-page private mapping and fill it with 1s. - uintptr_t addr; - ASSERT_THAT(addr = Map(0, 2 * kPageSize, PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0), - SyscallSucceeds()); - memset(addr_, 1, 2 * kPageSize); - MaybeSave(); - - // Fork to make the mapping copy-on-write. - pid_t const pid = fork(); - if (pid == 0) { - // The child process waits for the parent to SIGKILL it. - while (true) { - pause(); - } - } - ASSERT_THAT(pid, SyscallSucceeds()); - auto cleanup_child = Cleanup([&] { - EXPECT_THAT(kill(pid, SIGKILL), SyscallSucceeds()); - int status; - EXPECT_THAT(waitpid(pid, &status, 0), SyscallSucceedsWithValue(pid)); - }); - - // Induce a read-only Access of the first page of the mapping, which will not - // cause a copy. The usermem.Segment should be cached. - ASSERT_THAT(PwriteFd(fd.get(), addr_, kPageSize, 0), - SyscallSucceedsWithValue(kPageSize)); - - // Induce a writable Access of both pages of the mapping. This should - // invalidate the cached Segment. - ASSERT_THAT(PreadFd(zero_fd.get(), addr_, 2 * kPageSize, 0), - SyscallSucceedsWithValue(2 * kPageSize)); - - // Induce a read-only Access of the first page of the mapping again. It should - // read the 0s that were stored in the mapping by the read from /dev/zero. If - // the read failed to invalidate the cached Segment, it will instead read the - // 1s in the stale page. - ASSERT_THAT(PwriteFd(fd.get(), addr_, kPageSize, 0), - SyscallSucceedsWithValue(kPageSize)); - std::vector<char> buf(kPageSize); - ASSERT_THAT(PreadFd(fd.get(), buf.data(), kPageSize, 0), - SyscallSucceedsWithValue(kPageSize)); - for (size_t i = 0; i < kPageSize; i++) { - ASSERT_EQ(0, buf[i]) << "at offset " << i; - } -} - -TEST_F(MMapTest, NoReserve) { - const size_t kSize = 10 * 1 << 20; // 10M - uintptr_t addr; - ASSERT_THAT(addr = Map(0, kSize, PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0), - SyscallSucceeds()); - EXPECT_GT(addr, 0); - - // Check that every page can be read/written. Technically, writing to memory - // could SIGSEGV in case there is no more memory available. In gVisor it - // would never happen though because NORESERVE is ignored. In Linux, it's - // possible to fail, but allocation is small enough that it's highly likely - // to succeed. - for (size_t j = 0; j < kSize; j += kPageSize) { - EXPECT_EQ(0, reinterpret_cast<char*>(addr)[j]); - reinterpret_cast<char*>(addr)[j] = j; - } -} - -// Map more than the gVisor page-cache map unit (64k) and ensure that -// it is consistent with reading from the file. -TEST_F(MMapFileTest, Bug38498194) { - // Choose a sufficiently large map unit. - constexpr int kSize = 4 * 1024 * 1024; - EXPECT_THAT(ftruncate(fd_.get(), kSize), SyscallSucceeds()); - - // Map a large enough region so that multiple internal segments - // are created to back the mapping. - uintptr_t addr; - ASSERT_THAT( - addr = Map(0, kSize, PROT_READ | PROT_WRITE, MAP_SHARED, fd_.get(), 0), - SyscallSucceeds()); - - std::vector<char> expect(kSize, 'a'); - std::copy(expect.data(), expect.data() + expect.size(), - reinterpret_cast<volatile char*>(addr)); - - // Trigger writeback for gVisor. In Linux pages stay cached until - // it can't hold onto them anymore. - ASSERT_THAT(Unmap(), SyscallSucceeds()); - - std::vector<char> buf(kSize); - ASSERT_THAT(Read(buf.data(), buf.size()), - SyscallSucceedsWithValue(buf.size())); - EXPECT_EQ(buf, expect) << std::string(buf.data(), buf.size()); -} - -// Tests that reading from a file to a memory mapping of the same file does not -// deadlock. See b/34813270. -TEST_F(MMapFileTest, SelfRead) { - uintptr_t addr; - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED, - fd_.get(), 0), - SyscallSucceeds()); - EXPECT_THAT(Read(reinterpret_cast<char*>(addr), kPageSize / 2), - SyscallSucceedsWithValue(kPageSize / 2)); - // The resulting file contents are poorly-specified and irrelevant. -} - -// Tests that writing to a file from a memory mapping of the same file does not -// deadlock. Regression test for b/34813270. -TEST_F(MMapFileTest, SelfWrite) { - uintptr_t addr; - ASSERT_THAT(addr = Map(0, kPageSize, PROT_READ, MAP_SHARED, fd_.get(), 0), - SyscallSucceeds()); - EXPECT_THAT(Write(reinterpret_cast<char*>(addr), kPageSize / 2), - SyscallSucceedsWithValue(kPageSize / 2)); - // The resulting file contents are poorly-specified and irrelevant. -} - -TEST(MMapDeathTest, TruncateAfterCOWBreak) { - SetupGvisorDeathTest(); - - // Create and map a single-page file. - auto const temp_file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); - auto const fd = ASSERT_NO_ERRNO_AND_VALUE(Open(temp_file.path(), O_RDWR)); - ASSERT_THAT(ftruncate(fd.get(), kPageSize), SyscallSucceeds()); - auto const mapping = ASSERT_NO_ERRNO_AND_VALUE(Mmap( - nullptr, kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd.get(), 0)); - - // Write to this mapping, causing the page to be copied for write. - memset(mapping.ptr(), 'a', mapping.len()); - MaybeSave(); // Trigger a co-operative save cycle. - - // Truncate the file and expect it to invalidate the copied page. - ASSERT_THAT(ftruncate(fd.get(), 0), SyscallSucceeds()); - EXPECT_EXIT(*reinterpret_cast<volatile char*>(mapping.ptr()), - ::testing::KilledBySignal(SIGBUS), ""); -} - -// Regression test for #147. -TEST(MMapNoFixtureTest, MapReadOnlyAfterCreateWriteOnly) { - std::string filename = NewTempAbsPath(); - - // We have to create the file O_RDONLY to reproduce the bug because - // fsgofer.localFile.Create() silently upgrades O_WRONLY to O_RDWR, causing - // the cached "write-only" FD to be read/write and therefore usable by mmap(). - auto const ro_fd = ASSERT_NO_ERRNO_AND_VALUE( - Open(filename, O_RDONLY | O_CREAT | O_EXCL, 0666)); - - // Get a write-only FD for the same file, which should be ignored by mmap() - // (but isn't in #147). - auto const wo_fd = ASSERT_NO_ERRNO_AND_VALUE(Open(filename, O_WRONLY)); - ASSERT_THAT(ftruncate(wo_fd.get(), kPageSize), SyscallSucceeds()); - - auto const mapping = ASSERT_NO_ERRNO_AND_VALUE( - Mmap(nullptr, kPageSize, PROT_READ, MAP_SHARED, ro_fd.get(), 0)); - std::vector<char> buf(kPageSize); - // The test passes if this survives. - std::copy(static_cast<char*>(mapping.ptr()), - static_cast<char*>(mapping.endptr()), buf.data()); -} - -// Conditional on MAP_32BIT. -// This flag is supported only on x86-64, for 64-bit programs. -#ifdef __x86_64__ - -TEST(MMapNoFixtureTest, Map32Bit) { - auto const mapping = ASSERT_NO_ERRNO_AND_VALUE( - MmapAnon(kPageSize, PROT_NONE, MAP_PRIVATE | MAP_32BIT)); - EXPECT_LT(mapping.addr(), static_cast<uintptr_t>(1) << 32); - EXPECT_LE(mapping.endaddr(), static_cast<uintptr_t>(1) << 32); -} - -#endif // defined(__x86_64__) - -INSTANTIATE_TEST_SUITE_P( - ReadWriteSharedPrivate, MMapFileParamTest, - ::testing::Combine(::testing::ValuesIn({ - PROT_READ, - PROT_WRITE, - PROT_READ | PROT_WRITE, - }), - ::testing::ValuesIn({MAP_SHARED, MAP_PRIVATE}))); - -} // namespace - -} // namespace testing -} // namespace gvisor |