mirror of
https://github.com/netbirdio/gvisor.git
synced 2026-05-22 17:12:49 -07:00
Dean Deng
e4b2087602
After we change credentials, it is possible that we no longer have access to the sticky directory where we are trying to delete files. Use an open fd so this is not an issue. PiperOrigin-RevId: 319306255
162 lines
6.3 KiB
C++
162 lines
6.3 KiB
C++
// 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 <fcntl.h>
|
|
#include <grp.h>
|
|
#include <sys/prctl.h>
|
|
#include <sys/types.h>
|
|
#include <unistd.h>
|
|
|
|
#include <vector>
|
|
|
|
#include "gtest/gtest.h"
|
|
#include "absl/flags/flag.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"
|
|
#include "test/util/thread_util.h"
|
|
|
|
ABSL_FLAG(int32_t, scratch_uid, 65534, "first scratch UID");
|
|
ABSL_FLAG(int32_t, scratch_gid, 65534, "first scratch GID");
|
|
|
|
namespace gvisor {
|
|
namespace testing {
|
|
|
|
namespace {
|
|
|
|
TEST(StickyTest, StickyBitPermDenied) {
|
|
SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_SETUID)));
|
|
|
|
const TempPath parent = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
|
|
EXPECT_THAT(chmod(parent.path().c_str(), 0777 | S_ISVTX), SyscallSucceeds());
|
|
|
|
// After changing credentials below, we need to use an open fd to make
|
|
// modifications in the parent dir, because there is no guarantee that we will
|
|
// still have the ability to open it.
|
|
const FileDescriptor parent_fd =
|
|
ASSERT_NO_ERRNO_AND_VALUE(Open(parent.path(), O_DIRECTORY));
|
|
ASSERT_THAT(openat(parent_fd.get(), "file", O_CREAT), SyscallSucceeds());
|
|
ASSERT_THAT(mkdirat(parent_fd.get(), "dir", 0777), SyscallSucceeds());
|
|
ASSERT_THAT(symlinkat("xyz", parent_fd.get(), "link"), SyscallSucceeds());
|
|
|
|
// Drop privileges and change IDs only in child thread, or else this parent
|
|
// thread won't be able to open some log files after the test ends.
|
|
ScopedThread([&] {
|
|
// Drop privileges.
|
|
if (HaveCapability(CAP_FOWNER).ValueOrDie()) {
|
|
EXPECT_NO_ERRNO(SetCapability(CAP_FOWNER, false));
|
|
}
|
|
|
|
// Change EUID and EGID.
|
|
EXPECT_THAT(
|
|
syscall(SYS_setresgid, -1, absl::GetFlag(FLAGS_scratch_gid), -1),
|
|
SyscallSucceeds());
|
|
EXPECT_THAT(
|
|
syscall(SYS_setresuid, -1, absl::GetFlag(FLAGS_scratch_uid), -1),
|
|
SyscallSucceeds());
|
|
|
|
EXPECT_THAT(renameat(parent_fd.get(), "file", parent_fd.get(), "file2"),
|
|
SyscallFailsWithErrno(EPERM));
|
|
EXPECT_THAT(unlinkat(parent_fd.get(), "file", 0),
|
|
SyscallFailsWithErrno(EPERM));
|
|
EXPECT_THAT(unlinkat(parent_fd.get(), "dir", AT_REMOVEDIR),
|
|
SyscallFailsWithErrno(EPERM));
|
|
EXPECT_THAT(unlinkat(parent_fd.get(), "link", 0),
|
|
SyscallFailsWithErrno(EPERM));
|
|
});
|
|
}
|
|
|
|
TEST(StickyTest, StickyBitSameUID) {
|
|
SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_SETUID)));
|
|
|
|
const TempPath parent = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
|
|
EXPECT_THAT(chmod(parent.path().c_str(), 0777 | S_ISVTX), SyscallSucceeds());
|
|
|
|
// After changing credentials below, we need to use an open fd to make
|
|
// modifications in the parent dir, because there is no guarantee that we will
|
|
// still have the ability to open it.
|
|
const FileDescriptor parent_fd =
|
|
ASSERT_NO_ERRNO_AND_VALUE(Open(parent.path(), O_DIRECTORY));
|
|
ASSERT_THAT(openat(parent_fd.get(), "file", O_CREAT), SyscallSucceeds());
|
|
ASSERT_THAT(mkdirat(parent_fd.get(), "dir", 0777), SyscallSucceeds());
|
|
ASSERT_THAT(symlinkat("xyz", parent_fd.get(), "link"), SyscallSucceeds());
|
|
|
|
// Drop privileges and change IDs only in child thread, or else this parent
|
|
// thread won't be able to open some log files after the test ends.
|
|
ScopedThread([&] {
|
|
// Drop privileges.
|
|
if (HaveCapability(CAP_FOWNER).ValueOrDie()) {
|
|
EXPECT_NO_ERRNO(SetCapability(CAP_FOWNER, false));
|
|
}
|
|
|
|
// Change EGID.
|
|
EXPECT_THAT(
|
|
syscall(SYS_setresgid, -1, absl::GetFlag(FLAGS_scratch_gid), -1),
|
|
SyscallSucceeds());
|
|
|
|
// We still have the same EUID.
|
|
EXPECT_THAT(renameat(parent_fd.get(), "file", parent_fd.get(), "file2"),
|
|
SyscallSucceeds());
|
|
EXPECT_THAT(unlinkat(parent_fd.get(), "file2", 0), SyscallSucceeds());
|
|
EXPECT_THAT(unlinkat(parent_fd.get(), "dir", AT_REMOVEDIR),
|
|
SyscallSucceeds());
|
|
EXPECT_THAT(unlinkat(parent_fd.get(), "link", 0), SyscallSucceeds());
|
|
});
|
|
}
|
|
|
|
TEST(StickyTest, StickyBitCapFOWNER) {
|
|
SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_SETUID)));
|
|
|
|
const TempPath parent = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
|
|
EXPECT_THAT(chmod(parent.path().c_str(), 0777 | S_ISVTX), SyscallSucceeds());
|
|
|
|
// After changing credentials below, we need to use an open fd to make
|
|
// modifications in the parent dir, because there is no guarantee that we will
|
|
// still have the ability to open it.
|
|
const FileDescriptor parent_fd =
|
|
ASSERT_NO_ERRNO_AND_VALUE(Open(parent.path(), O_DIRECTORY));
|
|
ASSERT_THAT(openat(parent_fd.get(), "file", O_CREAT), SyscallSucceeds());
|
|
ASSERT_THAT(mkdirat(parent_fd.get(), "dir", 0777), SyscallSucceeds());
|
|
ASSERT_THAT(symlinkat("xyz", parent_fd.get(), "link"), SyscallSucceeds());
|
|
|
|
// Drop privileges and change IDs only in child thread, or else this parent
|
|
// thread won't be able to open some log files after the test ends.
|
|
ScopedThread([&] {
|
|
// Set PR_SET_KEEPCAPS.
|
|
EXPECT_THAT(prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0), SyscallSucceeds());
|
|
|
|
// Change EUID and EGID.
|
|
EXPECT_THAT(
|
|
syscall(SYS_setresgid, -1, absl::GetFlag(FLAGS_scratch_gid), -1),
|
|
SyscallSucceeds());
|
|
EXPECT_THAT(
|
|
syscall(SYS_setresuid, -1, absl::GetFlag(FLAGS_scratch_uid), -1),
|
|
SyscallSucceeds());
|
|
|
|
EXPECT_NO_ERRNO(SetCapability(CAP_FOWNER, true));
|
|
EXPECT_THAT(renameat(parent_fd.get(), "file", parent_fd.get(), "file2"),
|
|
SyscallSucceeds());
|
|
EXPECT_THAT(unlinkat(parent_fd.get(), "file2", 0), SyscallSucceeds());
|
|
EXPECT_THAT(unlinkat(parent_fd.get(), "dir", AT_REMOVEDIR),
|
|
SyscallSucceeds());
|
|
EXPECT_THAT(unlinkat(parent_fd.get(), "link", 0), SyscallSucceeds());
|
|
});
|
|
}
|
|
} // namespace
|
|
|
|
} // namespace testing
|
|
} // namespace gvisor
|