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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.
// Utilities for testing capabilities.
#ifndef GVISOR_TEST_UTIL_CAPABILITY_UTIL_H_
#define GVISOR_TEST_UTIL_CAPABILITY_UTIL_H_
#include <errno.h>
#include <linux/capability.h>
#include <sys/syscall.h>
#include <unistd.h>
#include "test/util/cleanup.h"
#include "test/util/posix_error.h"
#include "test/util/save_util.h"
#include "test/util/test_util.h"
#ifndef _LINUX_CAPABILITY_VERSION_3
#error Expecting _LINUX_CAPABILITY_VERSION_3 support
#endif
namespace gvisor {
namespace testing {
// HaveCapability returns true if the process has the specified EFFECTIVE
// capability.
inline PosixErrorOr<bool> HaveCapability(int cap) {
if (!cap_valid(cap)) {
return PosixError(EINVAL, "Invalid capability");
}
struct __user_cap_header_struct header = {_LINUX_CAPABILITY_VERSION_3, 0};
struct __user_cap_data_struct caps[_LINUX_CAPABILITY_U32S_3] = {};
RETURN_ERROR_IF_SYSCALL_FAIL(syscall(__NR_capget, &header, &caps));
MaybeSave();
return (caps[CAP_TO_INDEX(cap)].effective & CAP_TO_MASK(cap)) != 0;
}
// SetCapability sets the specified EFFECTIVE capability.
inline PosixError SetCapability(int cap, bool set) {
if (!cap_valid(cap)) {
return PosixError(EINVAL, "Invalid capability");
}
struct __user_cap_header_struct header = {_LINUX_CAPABILITY_VERSION_3, 0};
struct __user_cap_data_struct caps[_LINUX_CAPABILITY_U32S_3] = {};
RETURN_ERROR_IF_SYSCALL_FAIL(syscall(__NR_capget, &header, &caps));
MaybeSave();
if (set) {
caps[CAP_TO_INDEX(cap)].effective |= CAP_TO_MASK(cap);
} else {
caps[CAP_TO_INDEX(cap)].effective &= ~CAP_TO_MASK(cap);
}
header = {_LINUX_CAPABILITY_VERSION_3, 0};
RETURN_ERROR_IF_SYSCALL_FAIL(syscall(__NR_capset, &header, &caps));
MaybeSave();
return NoError();
}
// DropPermittedCapability drops the specified PERMITTED. The EFFECTIVE
// capabilities must be a subset of PERMITTED, so those are dropped as well.
inline PosixError DropPermittedCapability(int cap) {
if (!cap_valid(cap)) {
return PosixError(EINVAL, "Invalid capability");
}
struct __user_cap_header_struct header = {_LINUX_CAPABILITY_VERSION_3, 0};
struct __user_cap_data_struct caps[_LINUX_CAPABILITY_U32S_3] = {};
RETURN_ERROR_IF_SYSCALL_FAIL(syscall(__NR_capget, &header, &caps));
MaybeSave();
caps[CAP_TO_INDEX(cap)].effective &= ~CAP_TO_MASK(cap);
caps[CAP_TO_INDEX(cap)].permitted &= ~CAP_TO_MASK(cap);
header = {_LINUX_CAPABILITY_VERSION_3, 0};
RETURN_ERROR_IF_SYSCALL_FAIL(syscall(__NR_capset, &header, &caps));
MaybeSave();
return NoError();
}
PosixErrorOr<bool> CanCreateUserNamespace();
} // namespace testing
} // namespace gvisor
#endif // GVISOR_TEST_UTIL_CAPABILITY_UTIL_H_
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