Open source system call tests.

PiperOrigin-RevId: 224886231
Change-Id: I0fccb4d994601739d8b16b1d4e6b31f40297fb22

1 files changed, 211 insertions, 0 deletions

diff --git a/test/syscalls/linux/unlink.cc b/test/syscalls/linux/unlink.cc
new file mode 100644
index 000000000..4d5e0c6b6
--- /dev/null
+++ b/test/syscalls/linux/unlink.cc
@@ -0,0 +1,211 @@
+// Copyright 2018 Google LLC
+//
+// 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) {
+  std::string path = JoinPath(GetAbsoluteTestTmpdir(), "NewDir");
+  ASSERT_THAT(mkdir(path.c_str(), 0755), SyscallSucceeds());
+  EXPECT_THAT(rmdir(path.c_str()), SyscallSucceeds());
+}
+
+TEST(UnlinkTest, AtDir) {
+  int dirfd;
+  EXPECT_THAT(dirfd = open(GetAbsoluteTestTmpdir().c_str(), O_DIRECTORY, 0),
+              SyscallSucceeds());
+
+  std::string path = JoinPath(GetAbsoluteTestTmpdir(), "NewDir");
+  EXPECT_THAT(mkdir(path.c_str(), 0755), SyscallSucceeds());
+  EXPECT_THAT(unlinkat(dirfd, "NewDir", 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));
+  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) {
+  // 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());
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor