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Diffstat (limited to 'test/syscalls/linux/symlink.cc')
| -rw-r--r-- | test/syscalls/linux/symlink.cc | 442 |
1 files changed, 0 insertions, 442 deletions
diff --git a/test/syscalls/linux/symlink.cc b/test/syscalls/linux/symlink.cc deleted file mode 100644 index 4d9eba7f0..000000000 --- a/test/syscalls/linux/symlink.cc +++ /dev/null @@ -1,442 +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 <string.h> -#include <unistd.h> - -#include <string> - -#include "gtest/gtest.h" -#include "absl/time/clock.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 { - -mode_t FilePermission(const std::string& path) { - struct stat buf = {0}; - TEST_CHECK(lstat(path.c_str(), &buf) == 0); - return buf.st_mode & 0777; -} - -// Test that name collisions are checked on the new link path, not the source -// path. Regression test for b/31782115. -TEST(SymlinkTest, CanCreateSymlinkWithCachedSourceDirent) { - const std::string srcname = NewTempAbsPath(); - const std::string newname = NewTempAbsPath(); - const std::string basedir = std::string(Dirname(srcname)); - ASSERT_EQ(basedir, Dirname(newname)); - - ASSERT_THAT(chdir(basedir.c_str()), SyscallSucceeds()); - - // Open the source node to cause the underlying dirent to be cached. It will - // remain cached while we have the file open. - int fd; - ASSERT_THAT(fd = open(srcname.c_str(), O_CREAT | O_RDWR, 0666), - SyscallSucceeds()); - FileDescriptor fd_closer(fd); - - // Attempt to create a symlink. If the bug exists, this will fail since the - // dirent link creation code will check for a name collision on the source - // link name. - EXPECT_THAT(symlink(std::string(Basename(srcname)).c_str(), - std::string(Basename(newname)).c_str()), - SyscallSucceeds()); -} - -TEST(SymlinkTest, CanCreateSymlinkFile) { - const std::string oldname = NewTempAbsPath(); - const std::string newname = NewTempAbsPath(); - - int fd; - ASSERT_THAT(fd = open(oldname.c_str(), O_CREAT | O_RDWR, 0666), - SyscallSucceeds()); - EXPECT_THAT(close(fd), SyscallSucceeds()); - - EXPECT_THAT(symlink(oldname.c_str(), newname.c_str()), SyscallSucceeds()); - EXPECT_EQ(FilePermission(newname), 0777); - - auto link = ASSERT_NO_ERRNO_AND_VALUE(ReadLink(newname)); - EXPECT_EQ(oldname, link); - - EXPECT_THAT(unlink(newname.c_str()), SyscallSucceeds()); - EXPECT_THAT(unlink(oldname.c_str()), SyscallSucceeds()); -} - -TEST(SymlinkTest, CanCreateSymlinkDir) { - const std::string olddir = NewTempAbsPath(); - const std::string newdir = NewTempAbsPath(); - - EXPECT_THAT(mkdir(olddir.c_str(), 0777), SyscallSucceeds()); - EXPECT_THAT(symlink(olddir.c_str(), newdir.c_str()), SyscallSucceeds()); - EXPECT_EQ(FilePermission(newdir), 0777); - - auto link = ASSERT_NO_ERRNO_AND_VALUE(ReadLink(newdir)); - EXPECT_EQ(olddir, link); - - EXPECT_THAT(unlink(newdir.c_str()), SyscallSucceeds()); - - ASSERT_THAT(rmdir(olddir.c_str()), SyscallSucceeds()); -} - -TEST(SymlinkTest, CannotCreateSymlinkInReadOnlyDir) { - // 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)); - - const std::string olddir = NewTempAbsPath(); - ASSERT_THAT(mkdir(olddir.c_str(), 0444), SyscallSucceeds()); - - const std::string newdir = NewTempAbsPathInDir(olddir); - EXPECT_THAT(symlink(olddir.c_str(), newdir.c_str()), - SyscallFailsWithErrno(EACCES)); - - ASSERT_THAT(rmdir(olddir.c_str()), SyscallSucceeds()); -} - -TEST(SymlinkTest, CannotSymlinkOverExistingFile) { - const auto oldfile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); - const auto newfile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); - - EXPECT_THAT(symlink(oldfile.path().c_str(), newfile.path().c_str()), - SyscallFailsWithErrno(EEXIST)); -} - -TEST(SymlinkTest, CannotSymlinkOverExistingDir) { - const auto oldfile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); - const auto newdir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir()); - - EXPECT_THAT(symlink(oldfile.path().c_str(), newdir.path().c_str()), - SyscallFailsWithErrno(EEXIST)); -} - -TEST(SymlinkTest, OldnameIsEmpty) { - const std::string newname = NewTempAbsPath(); - EXPECT_THAT(symlink("", newname.c_str()), SyscallFailsWithErrno(ENOENT)); -} - -TEST(SymlinkTest, OldnameIsDangling) { - const std::string newname = NewTempAbsPath(); - EXPECT_THAT(symlink("/dangling", newname.c_str()), SyscallSucceeds()); - - // This is required for S/R random save tests, which pre-run this test - // in the same TEST_TMPDIR, which means that we need to clean it for any - // operations exclusively creating files, like symlink above. - EXPECT_THAT(unlink(newname.c_str()), SyscallSucceeds()); -} - -TEST(SymlinkTest, NewnameCannotExist) { - const std::string newname = - JoinPath(GetAbsoluteTestTmpdir(), "thisdoesnotexist", "foo"); - EXPECT_THAT(symlink("/thisdoesnotmatter", newname.c_str()), - SyscallFailsWithErrno(ENOENT)); -} - -TEST(SymlinkTest, CanEvaluateLink) { - const auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); - - // We are going to assert that the symlink inode id is the same as the linked - // file's inode id. In order for the inode id to be stable across - // save/restore, it must be kept open. The FileDescriptor type will do that - // for us automatically. - auto fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR)); - struct stat file_st; - EXPECT_THAT(fstat(fd.get(), &file_st), SyscallSucceeds()); - - const std::string link = NewTempAbsPath(); - EXPECT_THAT(symlink(file.path().c_str(), link.c_str()), SyscallSucceeds()); - EXPECT_EQ(FilePermission(link), 0777); - - auto linkfd = ASSERT_NO_ERRNO_AND_VALUE(Open(link.c_str(), O_RDWR)); - struct stat link_st; - EXPECT_THAT(fstat(linkfd.get(), &link_st), SyscallSucceeds()); - - // Check that in fact newname points to the file we expect. - EXPECT_EQ(file_st.st_dev, link_st.st_dev); - EXPECT_EQ(file_st.st_ino, link_st.st_ino); -} - -TEST(SymlinkTest, TargetIsNotMapped) { - const std::string oldname = NewTempAbsPath(); - const std::string newname = NewTempAbsPath(); - - int fd; - // Create the target so that when we read the link, it exists. - ASSERT_THAT(fd = open(oldname.c_str(), O_CREAT | O_RDWR, 0666), - SyscallSucceeds()); - EXPECT_THAT(close(fd), SyscallSucceeds()); - - // Create a symlink called newname that points to oldname. - EXPECT_THAT(symlink(oldname.c_str(), newname.c_str()), SyscallSucceeds()); - - std::vector<char> buf(1024); - int linksize; - // Read the link and assert that the oldname is still the same. - EXPECT_THAT(linksize = readlink(newname.c_str(), buf.data(), 1024), - SyscallSucceeds()); - EXPECT_EQ(0, strncmp(oldname.c_str(), buf.data(), linksize)); - - EXPECT_THAT(unlink(newname.c_str()), SyscallSucceeds()); - EXPECT_THAT(unlink(oldname.c_str()), SyscallSucceeds()); -} - -TEST(SymlinkTest, PreadFromSymlink) { - std::string name = NewTempAbsPath(); - int fd; - ASSERT_THAT(fd = open(name.c_str(), O_CREAT, 0644), SyscallSucceeds()); - ASSERT_THAT(close(fd), SyscallSucceeds()); - - std::string linkname = NewTempAbsPath(); - ASSERT_THAT(symlink(name.c_str(), linkname.c_str()), SyscallSucceeds()); - - ASSERT_THAT(fd = open(linkname.c_str(), O_RDONLY), SyscallSucceeds()); - - char buf[1024]; - EXPECT_THAT(pread64(fd, buf, 1024, 0), SyscallSucceeds()); - EXPECT_THAT(close(fd), SyscallSucceeds()); - - EXPECT_THAT(unlink(name.c_str()), SyscallSucceeds()); - EXPECT_THAT(unlink(linkname.c_str()), SyscallSucceeds()); -} - -TEST(SymlinkTest, PwriteToSymlink) { - std::string name = NewTempAbsPath(); - int fd; - ASSERT_THAT(fd = open(name.c_str(), O_CREAT, 0644), SyscallSucceeds()); - ASSERT_THAT(close(fd), SyscallSucceeds()); - - std::string linkname = NewTempAbsPath(); - ASSERT_THAT(symlink(name.c_str(), linkname.c_str()), SyscallSucceeds()); - - ASSERT_THAT(fd = open(linkname.c_str(), O_WRONLY), SyscallSucceeds()); - - const int data_size = 10; - const std::string data = std::string(data_size, 'a'); - EXPECT_THAT(pwrite64(fd, data.c_str(), data.size(), 0), - SyscallSucceedsWithValue(data.size())); - - ASSERT_THAT(close(fd), SyscallSucceeds()); - ASSERT_THAT(fd = open(name.c_str(), O_RDONLY), SyscallSucceeds()); - - char buf[data_size + 1]; - EXPECT_THAT(pread64(fd, buf, data.size(), 0), SyscallSucceeds()); - buf[data.size()] = '\0'; - EXPECT_STREQ(buf, data.c_str()); - - ASSERT_THAT(close(fd), SyscallSucceeds()); - - EXPECT_THAT(unlink(name.c_str()), SyscallSucceeds()); - EXPECT_THAT(unlink(linkname.c_str()), SyscallSucceeds()); -} - -TEST(SymlinkTest, SymlinkAtDegradedPermissions_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()); - auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileIn(dir.path())); - - int dirfd; - ASSERT_THAT(dirfd = open(dir.path().c_str(), O_DIRECTORY, 0), - SyscallSucceeds()); - - const DisableSave ds; // Permissions are dropped. - EXPECT_THAT(fchmod(dirfd, 0), SyscallSucceeds()); - - std::string basename = std::string(Basename(file.path())); - EXPECT_THAT(symlinkat("/dangling", dirfd, basename.c_str()), - SyscallFailsWithErrno(EACCES)); - EXPECT_THAT(close(dirfd), SyscallSucceeds()); -} - -TEST(SymlinkTest, ReadlinkAtDegradedPermissions_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()); - const std::string oldpath = NewTempAbsPathInDir(dir.path()); - const std::string oldbase = std::string(Basename(oldpath)); - ASSERT_THAT(symlink("/dangling", oldpath.c_str()), SyscallSucceeds()); - - int dirfd; - EXPECT_THAT(dirfd = open(dir.path().c_str(), O_DIRECTORY, 0), - SyscallSucceeds()); - - const DisableSave ds; // Permissions are dropped. - EXPECT_THAT(fchmod(dirfd, 0), SyscallSucceeds()); - - char buf[1024]; - int linksize; - EXPECT_THAT(linksize = readlinkat(dirfd, oldbase.c_str(), buf, 1024), - SyscallFailsWithErrno(EACCES)); - EXPECT_THAT(close(dirfd), SyscallSucceeds()); -} - -TEST(SymlinkTest, ChmodSymlink) { - auto target = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); - const std::string newpath = NewTempAbsPath(); - ASSERT_THAT(symlink(target.path().c_str(), newpath.c_str()), - SyscallSucceeds()); - EXPECT_EQ(FilePermission(newpath), 0777); - EXPECT_THAT(chmod(newpath.c_str(), 0666), SyscallSucceeds()); - EXPECT_EQ(FilePermission(newpath), 0777); -} - -// Test that following a symlink updates the atime on the symlink. -TEST(SymlinkTest, FollowUpdatesATime) { - const auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); - const std::string link = NewTempAbsPath(); - EXPECT_THAT(symlink(file.path().c_str(), link.c_str()), SyscallSucceeds()); - - // Lstat the symlink. - struct stat st_before_follow; - ASSERT_THAT(lstat(link.c_str(), &st_before_follow), SyscallSucceeds()); - - // Let the clock advance. - absl::SleepFor(absl::Seconds(1)); - - // Open the file via the symlink. - int fd; - ASSERT_THAT(fd = open(link.c_str(), O_RDWR, 0666), SyscallSucceeds()); - FileDescriptor fd_closer(fd); - - // Lstat the symlink again, and check that atime is updated. - struct stat st_after_follow; - ASSERT_THAT(lstat(link.c_str(), &st_after_follow), SyscallSucceeds()); - EXPECT_LT(st_before_follow.st_atime, st_after_follow.st_atime); -} - -TEST(SymlinkTest, SymlinkAtEmptyPath) { - auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); - auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir()); - - auto fd = - ASSERT_NO_ERRNO_AND_VALUE(Open(dir.path(), O_RDONLY | O_DIRECTORY, 0666)); - EXPECT_THAT(symlinkat(file.path().c_str(), fd.get(), ""), - SyscallFailsWithErrno(ENOENT)); -} - -class ParamSymlinkTest : public ::testing::TestWithParam<std::string> {}; - -// Test that creating an existing symlink with creat will create the target. -TEST_P(ParamSymlinkTest, CreatLinkCreatesTarget) { - const std::string target = GetParam(); - const std::string linkpath = NewTempAbsPath(); - - ASSERT_THAT(symlink(target.c_str(), linkpath.c_str()), SyscallSucceeds()); - - int fd; - EXPECT_THAT(fd = creat(linkpath.c_str(), 0666), SyscallSucceeds()); - ASSERT_THAT(close(fd), SyscallSucceeds()); - - ASSERT_THAT(chdir(GetAbsoluteTestTmpdir().c_str()), SyscallSucceeds()); - struct stat st; - EXPECT_THAT(stat(target.c_str(), &st), SyscallSucceeds()); - - ASSERT_THAT(unlink(linkpath.c_str()), SyscallSucceeds()); - ASSERT_THAT(unlink(target.c_str()), SyscallSucceeds()); -} - -// Test that opening an existing symlink with O_CREAT will create the target. -TEST_P(ParamSymlinkTest, OpenLinkCreatesTarget) { - const std::string target = GetParam(); - const std::string linkpath = NewTempAbsPath(); - - ASSERT_THAT(symlink(target.c_str(), linkpath.c_str()), SyscallSucceeds()); - - int fd; - EXPECT_THAT(fd = open(linkpath.c_str(), O_CREAT, 0666), SyscallSucceeds()); - ASSERT_THAT(close(fd), SyscallSucceeds()); - - ASSERT_THAT(chdir(GetAbsoluteTestTmpdir().c_str()), SyscallSucceeds()); - struct stat st; - EXPECT_THAT(stat(target.c_str(), &st), SyscallSucceeds()); - - ASSERT_THAT(unlink(linkpath.c_str()), SyscallSucceeds()); - ASSERT_THAT(unlink(target.c_str()), SyscallSucceeds()); -} - -// Test that opening a self-symlink with O_CREAT will fail with ELOOP. -TEST_P(ParamSymlinkTest, CreateExistingSelfLink) { - ASSERT_THAT(chdir(GetAbsoluteTestTmpdir().c_str()), SyscallSucceeds()); - - const std::string linkpath = GetParam(); - ASSERT_THAT(symlink(linkpath.c_str(), linkpath.c_str()), SyscallSucceeds()); - - EXPECT_THAT(open(linkpath.c_str(), O_CREAT, 0666), - SyscallFailsWithErrno(ELOOP)); - - ASSERT_THAT(unlink(linkpath.c_str()), SyscallSucceeds()); -} - -// Test that opening a file that is a symlink to its parent directory fails -// with ELOOP. -TEST_P(ParamSymlinkTest, CreateExistingParentLink) { - ASSERT_THAT(chdir(GetAbsoluteTestTmpdir().c_str()), SyscallSucceeds()); - - const std::string linkpath = GetParam(); - const std::string target = JoinPath(linkpath, "child"); - ASSERT_THAT(symlink(target.c_str(), linkpath.c_str()), SyscallSucceeds()); - - EXPECT_THAT(open(linkpath.c_str(), O_CREAT, 0666), - SyscallFailsWithErrno(ELOOP)); - - ASSERT_THAT(unlink(linkpath.c_str()), SyscallSucceeds()); -} - -// Test that opening an existing symlink with O_CREAT|O_EXCL will fail with -// EEXIST. -TEST_P(ParamSymlinkTest, OpenLinkExclFails) { - const std::string target = GetParam(); - const std::string linkpath = NewTempAbsPath(); - - ASSERT_THAT(symlink(target.c_str(), linkpath.c_str()), SyscallSucceeds()); - - EXPECT_THAT(open(linkpath.c_str(), O_CREAT | O_EXCL, 0666), - SyscallFailsWithErrno(EEXIST)); - - ASSERT_THAT(unlink(linkpath.c_str()), SyscallSucceeds()); -} - -// Test that opening an existing symlink with O_CREAT|O_NOFOLLOW will fail with -// ELOOP. -TEST_P(ParamSymlinkTest, OpenLinkNoFollowFails) { - const std::string target = GetParam(); - const std::string linkpath = NewTempAbsPath(); - - ASSERT_THAT(symlink(target.c_str(), linkpath.c_str()), SyscallSucceeds()); - - EXPECT_THAT(open(linkpath.c_str(), O_CREAT | O_NOFOLLOW, 0666), - SyscallFailsWithErrno(ELOOP)); - - ASSERT_THAT(unlink(linkpath.c_str()), SyscallSucceeds()); -} - -INSTANTIATE_TEST_SUITE_P(AbsAndRelTarget, ParamSymlinkTest, - ::testing::Values(NewTempAbsPath(), NewTempRelPath())); - -} // namespace - -} // namespace testing -} // namespace gvisor |