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// Copyright 2021 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 <stdint.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <time.h>
#include <iomanip>
#include <sstream>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "test/util/capability_util.h"
#include "test/util/fs_util.h"
#include "test/util/mount_util.h"
#include "test/util/temp_path.h"
#include "test/util/test_util.h"
#include "test/util/verity_util.h"
namespace gvisor {
namespace testing {
namespace {
class IoctlTest : public ::testing::Test {
protected:
void SetUp() override {
// Verity is implemented in VFS2.
SKIP_IF(IsRunningWithVFS1());
SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_SYS_ADMIN)));
// Mount a tmpfs file system, to be wrapped by a verity fs.
tmpfs_dir_ = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
ASSERT_THAT(mount("", tmpfs_dir_.path().c_str(), "tmpfs", 0, ""),
SyscallSucceeds());
// Create a new file in the tmpfs mount.
file_ = ASSERT_NO_ERRNO_AND_VALUE(
TempPath::CreateFileWith(tmpfs_dir_.path(), kContents, 0777));
filename_ = Basename(file_.path());
}
TempPath tmpfs_dir_;
TempPath file_;
std::string filename_;
};
TEST_F(IoctlTest, Enable) {
// Mount a verity fs on the existing tmpfs mount.
std::string mount_opts = "lower_path=" + tmpfs_dir_.path();
auto const verity_dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
ASSERT_THAT(
mount("", verity_dir.path().c_str(), "verity", 0, mount_opts.c_str()),
SyscallSucceeds());
// Confirm that the verity flag is absent.
int flag = 0;
auto const fd = ASSERT_NO_ERRNO_AND_VALUE(
Open(JoinPath(verity_dir.path(), filename_), O_RDONLY, 0777));
ASSERT_THAT(ioctl(fd.get(), FS_IOC_GETFLAGS, &flag), SyscallSucceeds());
EXPECT_EQ(flag & FS_VERITY_FL, 0);
// Enable the file and confirm that the verity flag is present.
ASSERT_THAT(ioctl(fd.get(), FS_IOC_ENABLE_VERITY), SyscallSucceeds());
ASSERT_THAT(ioctl(fd.get(), FS_IOC_GETFLAGS, &flag), SyscallSucceeds());
EXPECT_EQ(flag & FS_VERITY_FL, FS_VERITY_FL);
}
TEST_F(IoctlTest, Measure) {
// Mount a verity fs on the existing tmpfs mount.
std::string mount_opts = "lower_path=" + tmpfs_dir_.path();
auto const verity_dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
ASSERT_THAT(
mount("", verity_dir.path().c_str(), "verity", 0, mount_opts.c_str()),
SyscallSucceeds());
// Confirm that the file cannot be measured.
auto const fd = ASSERT_NO_ERRNO_AND_VALUE(
Open(JoinPath(verity_dir.path(), filename_), O_RDONLY, 0777));
uint8_t digest_array[sizeof(struct fsverity_digest) + kMaxDigestSize] = {0};
struct fsverity_digest* digest =
reinterpret_cast<struct fsverity_digest*>(digest_array);
digest->digest_size = kMaxDigestSize;
ASSERT_THAT(ioctl(fd.get(), FS_IOC_MEASURE_VERITY, digest),
SyscallFailsWithErrno(ENODATA));
// Enable the file and confirm that the file can be measured.
ASSERT_THAT(ioctl(fd.get(), FS_IOC_ENABLE_VERITY), SyscallSucceeds());
ASSERT_THAT(ioctl(fd.get(), FS_IOC_MEASURE_VERITY, digest),
SyscallSucceeds());
EXPECT_EQ(digest->digest_size, kDefaultDigestSize);
}
TEST_F(IoctlTest, Mount) {
std::string verity_dir = ASSERT_NO_ERRNO_AND_VALUE(
MountVerity(tmpfs_dir_.path(), filename_, /*targets=*/{}));
// Make sure the file can be open and read in the mounted verity fs.
auto const verity_fd = ASSERT_NO_ERRNO_AND_VALUE(
Open(JoinPath(verity_dir, filename_), O_RDONLY, 0777));
char buf[sizeof(kContents)];
EXPECT_THAT(ReadFd(verity_fd.get(), buf, sizeof(kContents)),
SyscallSucceeds());
}
TEST_F(IoctlTest, NonExistingFile) {
std::string verity_dir = ASSERT_NO_ERRNO_AND_VALUE(
MountVerity(tmpfs_dir_.path(), filename_, /*targets=*/{}));
// Confirm that opening a non-existing file in the verity-enabled directory
// triggers the expected error instead of verification failure.
EXPECT_THAT(
open(JoinPath(verity_dir, filename_ + "abc").c_str(), O_RDONLY, 0777),
SyscallFailsWithErrno(ENOENT));
}
TEST_F(IoctlTest, ModifiedFile) {
std::string verity_dir = ASSERT_NO_ERRNO_AND_VALUE(
MountVerity(tmpfs_dir_.path(), filename_, /*targets=*/{}));
// Modify the file and check verification failure upon reading from it.
auto const fd = ASSERT_NO_ERRNO_AND_VALUE(
Open(JoinPath(tmpfs_dir_.path(), filename_), O_RDWR, 0777));
ASSERT_NO_ERRNO(FlipRandomBit(fd.get(), sizeof(kContents) - 1));
auto const verity_fd = ASSERT_NO_ERRNO_AND_VALUE(
Open(JoinPath(verity_dir, filename_), O_RDONLY, 0777));
char buf[sizeof(kContents)];
EXPECT_THAT(pread(verity_fd.get(), buf, 16, 0), SyscallFailsWithErrno(EIO));
}
TEST_F(IoctlTest, ModifiedMerkle) {
std::string verity_dir = ASSERT_NO_ERRNO_AND_VALUE(
MountVerity(tmpfs_dir_.path(), filename_, /*targets=*/{}));
// Modify the Merkle file and check verification failure upon opening the
// corresponding file.
auto const fd = ASSERT_NO_ERRNO_AND_VALUE(
Open(MerklePath(JoinPath(tmpfs_dir_.path(), filename_)), O_RDWR, 0777));
auto stat = ASSERT_NO_ERRNO_AND_VALUE(Fstat(fd.get()));
ASSERT_NO_ERRNO(FlipRandomBit(fd.get(), stat.st_size));
EXPECT_THAT(open(JoinPath(verity_dir, filename_).c_str(), O_RDONLY, 0777),
SyscallFailsWithErrno(EIO));
}
TEST_F(IoctlTest, ModifiedDirMerkle) {
std::string verity_dir = ASSERT_NO_ERRNO_AND_VALUE(
MountVerity(tmpfs_dir_.path(), filename_, /*targets=*/{}));
// Modify the Merkle file for the parent directory and check verification
// failure upon opening the corresponding file.
auto const fd = ASSERT_NO_ERRNO_AND_VALUE(
Open(MerkleRootPath(JoinPath(tmpfs_dir_.path(), "root")), O_RDWR, 0777));
auto stat = ASSERT_NO_ERRNO_AND_VALUE(Fstat(fd.get()));
ASSERT_NO_ERRNO(FlipRandomBit(fd.get(), stat.st_size));
EXPECT_THAT(open(JoinPath(verity_dir, filename_).c_str(), O_RDONLY, 0777),
SyscallFailsWithErrno(EIO));
}
TEST_F(IoctlTest, Stat) {
std::string verity_dir = ASSERT_NO_ERRNO_AND_VALUE(
MountVerity(tmpfs_dir_.path(), filename_, /*targets=*/{}));
struct stat st;
EXPECT_THAT(stat(JoinPath(verity_dir, filename_).c_str(), &st),
SyscallSucceeds());
}
TEST_F(IoctlTest, ModifiedStat) {
std::string verity_dir = ASSERT_NO_ERRNO_AND_VALUE(
MountVerity(tmpfs_dir_.path(), filename_, /*targets=*/{}));
EXPECT_THAT(chmod(JoinPath(tmpfs_dir_.path(), filename_).c_str(), 0644),
SyscallSucceeds());
struct stat st;
EXPECT_THAT(stat(JoinPath(verity_dir, filename_).c_str(), &st),
SyscallFailsWithErrno(EIO));
}
TEST_F(IoctlTest, DeleteFile) {
std::string verity_dir = ASSERT_NO_ERRNO_AND_VALUE(
MountVerity(tmpfs_dir_.path(), filename_, /*targets=*/{}));
EXPECT_THAT(unlink(JoinPath(tmpfs_dir_.path(), filename_).c_str()),
SyscallSucceeds());
EXPECT_THAT(open(JoinPath(verity_dir, filename_).c_str(), O_RDONLY, 0777),
SyscallFailsWithErrno(EIO));
}
TEST_F(IoctlTest, DeleteMerkle) {
std::string verity_dir = ASSERT_NO_ERRNO_AND_VALUE(
MountVerity(tmpfs_dir_.path(), filename_, /*targets=*/{}));
EXPECT_THAT(
unlink(MerklePath(JoinPath(tmpfs_dir_.path(), filename_)).c_str()),
SyscallSucceeds());
EXPECT_THAT(open(JoinPath(verity_dir, filename_).c_str(), O_RDONLY, 0777),
SyscallFailsWithErrno(EIO));
}
TEST_F(IoctlTest, RenameFile) {
std::string verity_dir = ASSERT_NO_ERRNO_AND_VALUE(
MountVerity(tmpfs_dir_.path(), filename_, /*targets=*/{}));
std::string new_file_name = "renamed-" + filename_;
EXPECT_THAT(rename(JoinPath(tmpfs_dir_.path(), filename_).c_str(),
JoinPath(tmpfs_dir_.path(), new_file_name).c_str()),
SyscallSucceeds());
EXPECT_THAT(open(JoinPath(verity_dir, filename_).c_str(), O_RDONLY, 0777),
SyscallFailsWithErrno(EIO));
}
TEST_F(IoctlTest, RenameMerkle) {
std::string verity_dir = ASSERT_NO_ERRNO_AND_VALUE(
MountVerity(tmpfs_dir_.path(), filename_, /*targets=*/{}));
std::string new_file_name = "renamed-" + filename_;
EXPECT_THAT(
rename(MerklePath(JoinPath(tmpfs_dir_.path(), filename_)).c_str(),
MerklePath(JoinPath(tmpfs_dir_.path(), new_file_name)).c_str()),
SyscallSucceeds());
EXPECT_THAT(open(JoinPath(verity_dir, filename_).c_str(), O_RDONLY, 0777),
SyscallFailsWithErrno(EIO));
}
} // namespace
} // namespace testing
} // namespace gvisor
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