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// 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 <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include "gtest/gtest.h"
#include "test/util/capability_util.h"
#include "test/util/file_descriptor.h"
#include "test/util/fs_util.h"
#include "test/util/posix_error.h"
#include "test/util/temp_path.h"
#include "test/util/temp_umask.h"
#include "test/util/test_util.h"
namespace gvisor {
namespace testing {
namespace {
TEST(CreateTest, TmpFile) {
auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
EXPECT_NO_ERRNO(Open(JoinPath(dir.path(), "a"), O_RDWR | O_CREAT, 0666));
}
TEST(CreateTest, ExistingFile) {
auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
auto path = JoinPath(dir.path(), "ExistingFile");
EXPECT_NO_ERRNO(Open(path, O_RDWR | O_CREAT, 0666));
EXPECT_NO_ERRNO(Open(path, O_RDWR | O_CREAT, 0666));
}
TEST(CreateTest, CreateAtFile) {
auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
auto dirfd = ASSERT_NO_ERRNO_AND_VALUE(Open(dir.path(), O_DIRECTORY, 0666));
int fd;
EXPECT_THAT(fd = openat(dirfd.get(), "CreateAtFile", O_RDWR | O_CREAT, 0666),
SyscallSucceeds());
EXPECT_THAT(close(fd), SyscallSucceeds());
}
TEST(CreateTest, HonorsUmask) {
const DisableSave ds; // file cannot be re-opened as writable.
auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
TempUmask mask(0222);
auto fd = ASSERT_NO_ERRNO_AND_VALUE(
Open(JoinPath(dir.path(), "UmaskedFile"), O_RDWR | O_CREAT, 0666));
struct stat statbuf;
ASSERT_THAT(fstat(fd.get(), &statbuf), SyscallSucceeds());
EXPECT_EQ(0444, statbuf.st_mode & 0777);
}
TEST(CreateTest, CreateExclusively) {
auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
auto path = JoinPath(dir.path(), "foo");
EXPECT_NO_ERRNO(Open(path, O_CREAT | O_RDWR, 0644));
EXPECT_THAT(open(path.c_str(), O_CREAT | O_EXCL | O_RDWR, 0644),
SyscallFailsWithErrno(EEXIST));
}
TEST(CreateTest, CreatWithOTrunc) {
auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
ASSERT_THAT(open(dir.path().c_str(), O_CREAT | O_TRUNC, 0666),
SyscallFailsWithErrno(EISDIR));
}
TEST(CreateTest, CreatDirWithOTruncAndReadOnly) {
auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
ASSERT_THAT(open(dir.path().c_str(), O_CREAT | O_TRUNC | O_RDONLY, 0666),
SyscallFailsWithErrno(EISDIR));
}
TEST(CreateTest, CreatFileWithOTruncAndReadOnly) {
auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
auto path = JoinPath(dir.path(), "foo");
ASSERT_NO_ERRNO(Open(path, O_RDWR | O_CREAT, 0666));
ASSERT_NO_ERRNO(Open(path, O_CREAT | O_TRUNC | O_RDONLY, 0666));
}
TEST(CreateTest, CreateFailsOnDirWithoutWritePerms) {
// Make sure we don't have CAP_DAC_OVERRIDE, since that allows the user to
// always override directory permissions.
AutoCapability cap(CAP_DAC_OVERRIDE, false);
auto parent = ASSERT_NO_ERRNO_AND_VALUE(
TempPath::CreateDirWith(GetAbsoluteTestTmpdir(), 0555));
auto file = JoinPath(parent.path(), "foo");
ASSERT_THAT(open(file.c_str(), O_CREAT | O_RDWR, 0644),
SyscallFailsWithErrno(EACCES));
}
// A file originally created RW, but opened RO can later be opened RW.
// Regression test for b/65385065.
TEST(CreateTest, OpenCreateROThenRW) {
TempPath file(NewTempAbsPath());
// Create a RW file, but only open it RO.
FileDescriptor fd1 = ASSERT_NO_ERRNO_AND_VALUE(
Open(file.path(), O_CREAT | O_EXCL | O_RDONLY, 0644));
// Now get a RW FD.
FileDescriptor fd2 = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR));
// fd1 is not writable, but fd2 is.
char c = 'a';
EXPECT_THAT(WriteFd(fd1.get(), &c, 1), SyscallFailsWithErrno(EBADF));
EXPECT_THAT(WriteFd(fd2.get(), &c, 1), SyscallSucceedsWithValue(1));
}
TEST(CreateTest, ChmodReadToWriteBetweenOpens) {
// Make sure we don't have CAP_DAC_OVERRIDE, since that allows the user to
// override file read/write permissions. CAP_DAC_READ_SEARCH needs to be
// cleared for the same reason.
AutoCapability cap1(CAP_DAC_OVERRIDE, false);
AutoCapability cap2(CAP_DAC_READ_SEARCH, false);
const TempPath file =
ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileMode(0400));
const FileDescriptor rfd =
ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDONLY));
// Cannot restore after making permissions more restrictive.
const DisableSave ds;
ASSERT_THAT(fchmod(rfd.get(), 0200), SyscallSucceeds());
EXPECT_THAT(open(file.path().c_str(), O_RDONLY),
SyscallFailsWithErrno(EACCES));
const FileDescriptor wfd =
ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_WRONLY));
char c = 'x';
EXPECT_THAT(write(wfd.get(), &c, 1), SyscallSucceedsWithValue(1));
c = 0;
EXPECT_THAT(read(rfd.get(), &c, 1), SyscallSucceedsWithValue(1));
EXPECT_EQ(c, 'x');
}
TEST(CreateTest, ChmodWriteToReadBetweenOpens) {
// Make sure we don't have CAP_DAC_OVERRIDE, since that allows the user to
// override file read/write permissions.
AutoCapability cap(CAP_DAC_OVERRIDE, false);
const TempPath file =
ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileMode(0200));
const FileDescriptor wfd =
ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_WRONLY));
// Cannot restore after making permissions more restrictive.
const DisableSave ds;
ASSERT_THAT(fchmod(wfd.get(), 0400), SyscallSucceeds());
EXPECT_THAT(open(file.path().c_str(), O_WRONLY),
SyscallFailsWithErrno(EACCES));
const FileDescriptor rfd =
ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDONLY));
char c = 'x';
EXPECT_THAT(write(wfd.get(), &c, 1), SyscallSucceedsWithValue(1));
c = 0;
EXPECT_THAT(read(rfd.get(), &c, 1), SyscallSucceedsWithValue(1));
EXPECT_EQ(c, 'x');
}
TEST(CreateTest, CreateWithReadFlagNotAllowedByMode) {
// The only time we can open a file with flags forbidden by its permissions
// is when we are creating the file. We cannot re-open with the same flags,
// so we cannot restore an fd obtained from such an operation.
const DisableSave ds;
// Make sure we don't have CAP_DAC_OVERRIDE, since that allows the user to
// override file read/write permissions. CAP_DAC_READ_SEARCH needs to be
// cleared for the same reason.
AutoCapability cap1(CAP_DAC_OVERRIDE, false);
AutoCapability cap2(CAP_DAC_READ_SEARCH, false);
// Create and open a file with read flag but without read permissions.
const std::string path = NewTempAbsPath();
const FileDescriptor rfd =
ASSERT_NO_ERRNO_AND_VALUE(Open(path, O_CREAT | O_RDONLY, 0222));
EXPECT_THAT(open(path.c_str(), O_RDONLY), SyscallFailsWithErrno(EACCES));
const FileDescriptor wfd = ASSERT_NO_ERRNO_AND_VALUE(Open(path, O_WRONLY));
char c = 'x';
EXPECT_THAT(write(wfd.get(), &c, 1), SyscallSucceedsWithValue(1));
c = 0;
EXPECT_THAT(read(rfd.get(), &c, 1), SyscallSucceedsWithValue(1));
EXPECT_EQ(c, 'x');
}
TEST(CreateTest, CreateWithWriteFlagNotAllowedByMode) {
// The only time we can open a file with flags forbidden by its permissions
// is when we are creating the file. We cannot re-open with the same flags,
// so we cannot restore an fd obtained from such an operation.
const DisableSave ds;
// Make sure we don't have CAP_DAC_OVERRIDE, since that allows the user to
// override file read/write permissions.
AutoCapability cap(CAP_DAC_OVERRIDE, false);
// Create and open a file with write flag but without write permissions.
const std::string path = NewTempAbsPath();
const FileDescriptor wfd =
ASSERT_NO_ERRNO_AND_VALUE(Open(path, O_CREAT | O_WRONLY, 0444));
EXPECT_THAT(open(path.c_str(), O_WRONLY), SyscallFailsWithErrno(EACCES));
const FileDescriptor rfd = ASSERT_NO_ERRNO_AND_VALUE(Open(path, O_RDONLY));
char c = 'x';
EXPECT_THAT(write(wfd.get(), &c, 1), SyscallSucceedsWithValue(1));
c = 0;
EXPECT_THAT(read(rfd.get(), &c, 1), SyscallSucceedsWithValue(1));
EXPECT_EQ(c, 'x');
}
} // namespace
} // namespace testing
} // namespace gvisor
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