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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 <unistd.h>
#include "gtest/gtest.h"
#include "absl/strings/str_cat.h"
#include "test/util/capability_util.h"
#include "test/util/file_descriptor.h"
#include "test/util/fs_util.h"
#include "test/util/temp_path.h"
#include "test/util/test_util.h"
namespace gvisor {
namespace testing {
namespace {
TEST(UnlinkTest, IsDir) {
auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
EXPECT_THAT(unlink(dir.path().c_str()), SyscallFailsWithErrno(EISDIR));
}
TEST(UnlinkTest, DirNotEmpty) {
auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
int fd;
std::string path = JoinPath(dir.path(), "ExistingFile");
EXPECT_THAT(fd = open(path.c_str(), O_RDWR | O_CREAT, 0666),
SyscallSucceeds());
EXPECT_THAT(close(fd), SyscallSucceeds());
EXPECT_THAT(rmdir(dir.path().c_str()), SyscallFailsWithErrno(ENOTEMPTY));
}
TEST(UnlinkTest, Rmdir) {
auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
EXPECT_THAT(rmdir(dir.path().c_str()), SyscallSucceeds());
}
TEST(UnlinkTest, AtDir) {
int dirfd;
auto tmpdir = GetAbsoluteTestTmpdir();
EXPECT_THAT(dirfd = open(tmpdir.c_str(), O_DIRECTORY, 0), SyscallSucceeds());
auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDirIn(tmpdir));
auto dir_relpath =
ASSERT_NO_ERRNO_AND_VALUE(GetRelativePath(tmpdir, dir.path()));
EXPECT_THAT(unlinkat(dirfd, dir_relpath.c_str(), AT_REMOVEDIR),
SyscallSucceeds());
ASSERT_THAT(close(dirfd), SyscallSucceeds());
}
TEST(UnlinkTest, AtDirDegradedPermissions_NoRandomSave) {
// Drop capabilities that allow us to override file and directory permissions.
ASSERT_NO_ERRNO(SetCapability(CAP_DAC_OVERRIDE, false));
ASSERT_NO_ERRNO(SetCapability(CAP_DAC_READ_SEARCH, false));
auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
int dirfd;
ASSERT_THAT(dirfd = open(dir.path().c_str(), O_DIRECTORY, 0),
SyscallSucceeds());
std::string sub_dir = JoinPath(dir.path(), "NewDir");
EXPECT_THAT(mkdir(sub_dir.c_str(), 0755), SyscallSucceeds());
EXPECT_THAT(fchmod(dirfd, 0444), SyscallSucceeds());
EXPECT_THAT(unlinkat(dirfd, "NewDir", AT_REMOVEDIR),
SyscallFailsWithErrno(EACCES));
ASSERT_THAT(close(dirfd), SyscallSucceeds());
}
// Files cannot be unlinked if the parent is not writable and executable.
TEST(UnlinkTest, ParentDegradedPermissions) {
// Drop capabilities that allow us to override file and directory permissions.
ASSERT_NO_ERRNO(SetCapability(CAP_DAC_OVERRIDE, false));
ASSERT_NO_ERRNO(SetCapability(CAP_DAC_READ_SEARCH, false));
auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileIn(dir.path()));
ASSERT_THAT(chmod(dir.path().c_str(), 0000), SyscallSucceeds());
struct stat st;
ASSERT_THAT(stat(file.path().c_str(), &st), SyscallFailsWithErrno(EACCES));
ASSERT_THAT(unlinkat(AT_FDCWD, file.path().c_str(), 0),
SyscallFailsWithErrno(EACCES));
// Non-existent files also return EACCES.
const std::string nonexist = JoinPath(dir.path(), "doesnotexist");
ASSERT_THAT(stat(nonexist.c_str(), &st), SyscallFailsWithErrno(EACCES));
ASSERT_THAT(unlinkat(AT_FDCWD, nonexist.c_str(), 0),
SyscallFailsWithErrno(EACCES));
}
TEST(UnlinkTest, AtBad) {
int dirfd;
EXPECT_THAT(dirfd = open(GetAbsoluteTestTmpdir().c_str(), O_DIRECTORY, 0),
SyscallSucceeds());
// Try removing a directory as a file.
std::string path = JoinPath(GetAbsoluteTestTmpdir(), "NewDir");
EXPECT_THAT(mkdir(path.c_str(), 0755), SyscallSucceeds());
EXPECT_THAT(unlinkat(dirfd, "NewDir", 0), SyscallFailsWithErrno(EISDIR));
EXPECT_THAT(unlinkat(dirfd, "NewDir", AT_REMOVEDIR), SyscallSucceeds());
// Try removing a file as a directory.
int fd;
EXPECT_THAT(fd = openat(dirfd, "UnlinkAtFile", O_RDWR | O_CREAT, 0666),
SyscallSucceeds());
EXPECT_THAT(unlinkat(dirfd, "UnlinkAtFile", AT_REMOVEDIR),
SyscallFailsWithErrno(ENOTDIR));
EXPECT_THAT(unlinkat(dirfd, "UnlinkAtFile/", 0),
SyscallFailsWithErrno(ENOTDIR));
ASSERT_THAT(close(fd), SyscallSucceeds());
EXPECT_THAT(unlinkat(dirfd, "UnlinkAtFile", 0), SyscallSucceeds());
// Cleanup.
ASSERT_THAT(close(dirfd), SyscallSucceeds());
}
TEST(UnlinkTest, AbsTmpFile) {
int fd;
std::string path = JoinPath(GetAbsoluteTestTmpdir(), "ExistingFile");
EXPECT_THAT(fd = open(path.c_str(), O_RDWR | O_CREAT, 0666),
SyscallSucceeds());
EXPECT_THAT(close(fd), SyscallSucceeds());
EXPECT_THAT(unlink(path.c_str()), SyscallSucceeds());
}
TEST(UnlinkTest, TooLongName) {
EXPECT_THAT(unlink(std::vector<char>(16384, '0').data()),
SyscallFailsWithErrno(ENAMETOOLONG));
}
TEST(UnlinkTest, BadNamePtr) {
EXPECT_THAT(unlink(reinterpret_cast<char*>(1)),
SyscallFailsWithErrno(EFAULT));
}
TEST(UnlinkTest, AtFile) {
int dirfd;
EXPECT_THAT(dirfd = open(GetAbsoluteTestTmpdir().c_str(), O_DIRECTORY, 0666),
SyscallSucceeds());
int fd;
EXPECT_THAT(fd = openat(dirfd, "UnlinkAtFile", O_RDWR | O_CREAT, 0666),
SyscallSucceeds());
EXPECT_THAT(close(fd), SyscallSucceeds());
EXPECT_THAT(unlinkat(dirfd, "UnlinkAtFile", 0), SyscallSucceeds());
}
TEST(UnlinkTest, OpenFile_NoRandomSave) {
// We can't save unlinked file unless they are on tmpfs.
const DisableSave ds;
auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
int fd;
EXPECT_THAT(fd = open(file.path().c_str(), O_RDWR, 0666), SyscallSucceeds());
EXPECT_THAT(unlink(file.path().c_str()), SyscallSucceeds());
EXPECT_THAT(close(fd), SyscallSucceeds());
}
TEST(UnlinkTest, CannotRemoveDots) {
auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
const std::string self = JoinPath(file.path(), ".");
ASSERT_THAT(unlink(self.c_str()), SyscallFailsWithErrno(ENOTDIR));
const std::string parent = JoinPath(file.path(), "..");
ASSERT_THAT(unlink(parent.c_str()), SyscallFailsWithErrno(ENOTDIR));
}
TEST(UnlinkTest, CannotRemoveRoot) {
ASSERT_THAT(unlinkat(-1, "/", AT_REMOVEDIR), SyscallFailsWithErrno(EBUSY));
}
TEST(UnlinkTest, CannotRemoveRootWithAtDir) {
const FileDescriptor dirfd = ASSERT_NO_ERRNO_AND_VALUE(
Open(GetAbsoluteTestTmpdir(), O_DIRECTORY, 0666));
ASSERT_THAT(unlinkat(dirfd.get(), "/", AT_REMOVEDIR),
SyscallFailsWithErrno(EBUSY));
}
TEST(RmdirTest, CannotRemoveDots) {
auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
const std::string self = JoinPath(dir.path(), ".");
ASSERT_THAT(rmdir(self.c_str()), SyscallFailsWithErrno(EINVAL));
const std::string parent = JoinPath(dir.path(), "..");
ASSERT_THAT(rmdir(parent.c_str()), SyscallFailsWithErrno(ENOTEMPTY));
}
TEST(RmdirTest, CanRemoveWithTrailingSlashes) {
auto dir1 = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
const std::string slash = absl::StrCat(dir1.path(), "/");
ASSERT_THAT(rmdir(slash.c_str()), SyscallSucceeds());
auto dir2 = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
const std::string slashslash = absl::StrCat(dir2.path(), "//");
ASSERT_THAT(rmdir(slashslash.c_str()), SyscallSucceeds());
}
TEST(UnlinkTest, UnlinkAtEmptyPath) {
auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileIn(dir.path()));
auto fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666));
EXPECT_THAT(unlinkat(fd.get(), "", 0), SyscallFailsWithErrno(ENOENT));
auto dirInDir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDirIn(dir.path()));
auto dirFD = ASSERT_NO_ERRNO_AND_VALUE(
Open(dirInDir.path(), O_RDONLY | O_DIRECTORY, 0666));
EXPECT_THAT(unlinkat(dirFD.get(), "", AT_REMOVEDIR),
SyscallFailsWithErrno(ENOENT));
}
} // namespace
} // namespace testing
} // namespace gvisor
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