platform_system_core/init/capabilities.h
Luis Hector Chavez 94fb5b0bef init: Drop inheritable capabilities when switching uids
This change explicitly drops all inheritable capabilities (and, by
extension, ambient capabilities) when there are no explicit capabilities
being set by a service and the user is changed. This prevents Android
running in a container from accidentally granting extra capabilities to
services.

Bug: 69320306
Test: aosp_sailfish still boots
Test: sailfish:/ $ grep Cap /proc/`pidof android.hardware.audio@2.0-service`/status
      CapInh: 0000000000000000
      CapPrm: 0000000000000000
      CapEff: 0000000000000000
      CapBnd: 0000003fffffffff
      CapAmb: 0000000000000000
Test: sailfish:/ $ grep Cap /proc/`pidof logd`/status
      CapInh: 0000000000000000
      CapPrm: 0000000440000000
      CapEff: 0000000440000000
      CapBnd: 0000003fffffffff
      CapAmb: 0000000000000000
Test: Android in Chrome OS still boots
Test: localhost ~ # grep Cap /proc/`pidof android.hardware.audio@2.0-service`/status
      CapInh: 0000000000000000
      CapPrm: 0000000000000000
      CapEff: 0000000000000000
      CapBnd: 000000006daefdff
      CapAmb: 0000000000000000
Test: localhost ~ # grep Cap /proc/`pidof logd`/status
      CapInh: 0000000000000000
      CapPrm: 0000000040000000
      CapEff: 0000000040000000
      CapBnd: 000000006daefdff
      CapAmb: 0000000000000000

Change-Id: I9218f2e27ff4fb4d91d50f9a98c0fdb4e272952c
2017-11-17 09:11:37 -08:00

43 lines
1.2 KiB
C++

// Copyright (C) 2016 The Android Open Source Project
//
// 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.
#ifndef _INIT_CAPABILITIES_H
#define _INIT_CAPABILITIES_H
#include <sys/capability.h>
#include <bitset>
#include <string>
#include <type_traits>
namespace android {
namespace init {
struct CapDeleter {
void operator()(cap_t caps) const { cap_free(caps); }
};
using CapSet = std::bitset<CAP_LAST_CAP + 1>;
using ScopedCaps = std::unique_ptr<std::remove_pointer<cap_t>::type, CapDeleter>;
int LookupCap(const std::string& cap_name);
bool CapAmbientSupported();
unsigned int GetLastValidCap();
bool SetCapsForExec(const CapSet& to_keep);
bool DropInheritableCaps();
} // namespace init
} // namespace android
#endif // _INIT_CAPABILITIES_H