tequilaOS/platform_system_core
2
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity
platform_system_core/init/service.h
Jorge Lucangeli Obes 24b29132a0 init: Add support for ambient capabilities. 
Ambient capabilities are inherited in a straightforward way across
execve(2):

"
If you are nonroot but you have a capability, you can add it to pA.
If you do so, your children get that capability in pA, pP, and pE.
For example, you can set pA = CAP_NET_BIND_SERVICE, and your
children can automatically bind low-numbered ports.
"

This will allow us to get rid of the special meaning for AID_NET_ADMIN
and AID_NET_RAW, and if desired, to reduce the use of file capabilities
(which grant capabilities to any process that can execute the file). An
additional benefit of the latter is that a single .rc file can specify
all properties for a service, without having to rely on a separate file
for file capabilities.

Ambient capabilities are supported starting with kernel 4.3 and have
been backported to all Android common kernels back to 3.10.

I chose to not use Minijail here (though I'm still using libcap) for
two reasons:

1-The Minijail code is designed to work in situations where the process
is holding any set of capabilities, so it's more complex. The situation
when forking from init allows for simpler code.

2-The way Minijail is structured right now, we would not be able to
make the required SELinux calls between UID/GID dropping and other priv
dropping code. In the future, it will make sense to add some sort of
"hook" to Minijail so that it can be used in situations where we want
to do other operations between some of the privilege-dropping
operations carried out by Minijail.

Bug: 32438163
Test: Use sample service.
Change-Id: I3226cc95769d1beacbae619cb6c6e6a5425890fb
2016-11-01 19:56:14 -04:00

225 lines
8.2 KiB
C++
Raw Blame History

/*
* Copyright (C) 2015 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_SERVICE_H
#define _INIT_SERVICE_H
#include <sys/types.h>
#include <cutils/iosched_policy.h>
#include <memory>
#include <string>
#include <vector>
#include "action.h"
#include "capabilities.h"
#include "init_parser.h"
#include "keyword_map.h"
#define SVC_DISABLED 0x001 // do not autostart with class
#define SVC_ONESHOT 0x002 // do not restart on exit
#define SVC_RUNNING 0x004 // currently active
#define SVC_RESTARTING 0x008 // waiting to restart
#define SVC_CONSOLE 0x010 // requires console
#define SVC_CRITICAL 0x020 // will reboot into recovery if keeps crashing
#define SVC_RESET 0x040 // Use when stopping a process,
// but not disabling so it can be restarted with its class.
#define SVC_RC_DISABLED 0x080 // Remember if the disabled flag was set in the rc script.
#define SVC_RESTART 0x100 // Use to safely restart (stop, wait, start) a service.
#define SVC_DISABLED_START 0x200 // A start was requested but it was disabled at the time.
#define SVC_EXEC 0x400 // This synthetic service corresponds to an 'exec'.
#define NR_SVC_SUPP_GIDS 12 // twelve supplementary groups
class Action;
class ServiceManager;
struct SocketInfo {
SocketInfo();
SocketInfo(const std::string& name, const std::string& type, uid_t uid,
gid_t gid, int perm, const std::string& socketcon);
std::string name;
std::string type;
uid_t uid;
gid_t gid;
int perm;
std::string socketcon;
};
struct ServiceEnvironmentInfo {
ServiceEnvironmentInfo();
ServiceEnvironmentInfo(const std::string& name, const std::string& value);
std::string name;
std::string value;
};
class Service {
public:
Service(const std::string& name, const std::string& classname,
const std::vector<std::string>& args);
Service(const std::string& name, const std::string& classname,
unsigned flags, uid_t uid, gid_t gid,
const std::vector<gid_t>& supp_gids, const CapSet& capabilities,
unsigned namespace_flags, const std::string& seclabel,
const std::vector<std::string>& args);
bool ParseLine(const std::vector<std::string>& args, std::string* err);
bool Start();
bool StartIfNotDisabled();
bool Enable();
void Reset();
void Stop();
void Terminate();
void Restart();
void RestartIfNeeded(time_t& process_needs_restart);
bool Reap();
void DumpState() const;
const std::string& name() const { return name_; }
const std::string& classname() const { return classname_; }
unsigned flags() const { return flags_; }
pid_t pid() const { return pid_; }
uid_t uid() const { return uid_; }
gid_t gid() const { return gid_; }
int priority() const { return priority_; }
const std::vector<gid_t>& supp_gids() const { return supp_gids_; }
const std::string& seclabel() const { return seclabel_; }
const std::vector<int>& keycodes() const { return keycodes_; }
int keychord_id() const { return keychord_id_; }
void set_keychord_id(int keychord_id) { keychord_id_ = keychord_id; }
const std::vector<std::string>& args() const { return args_; }
private:
using OptionParser = bool (Service::*) (const std::vector<std::string>& args,
std::string* err);
class OptionParserMap;
void NotifyStateChange(const std::string& new_state) const;
void StopOrReset(int how);
void ZapStdio() const;
void OpenConsole() const;
void PublishSocket(const std::string& name, int fd) const;
void KillProcessGroup(int signal);
void CreateSockets(const std::string& scon);
void SetProcessAttributes();
bool ParseCapabilities(const std::vector<std::string>& args, std::string *err);
bool ParseClass(const std::vector<std::string>& args, std::string* err);
bool ParseConsole(const std::vector<std::string>& args, std::string* err);
bool ParseCritical(const std::vector<std::string>& args, std::string* err);
bool ParseDisabled(const std::vector<std::string>& args, std::string* err);
bool ParseGroup(const std::vector<std::string>& args, std::string* err);
bool ParsePriority(const std::vector<std::string>& args, std::string* err);
bool ParseIoprio(const std::vector<std::string>& args, std::string* err);
bool ParseKeycodes(const std::vector<std::string>& args, std::string* err);
bool ParseOneshot(const std::vector<std::string>& args, std::string* err);
bool ParseOnrestart(const std::vector<std::string>& args, std::string* err);
bool ParseOomScoreAdjust(const std::vector<std::string>& args, std::string* err);
bool ParseNamespace(const std::vector<std::string>& args, std::string* err);
bool ParseSeclabel(const std::vector<std::string>& args, std::string* err);
bool ParseSetenv(const std::vector<std::string>& args, std::string* err);
bool ParseSocket(const std::vector<std::string>& args, std::string* err);
bool ParseUser(const std::vector<std::string>& args, std::string* err);
bool ParseWritepid(const std::vector<std::string>& args, std::string* err);
std::string name_;
std::string classname_;
std::string console_;
unsigned flags_;
pid_t pid_;
time_t time_started_; // time of last start
time_t time_crashed_; // first crash within inspection window
int nr_crashed_; // number of times crashed within window
uid_t uid_;
gid_t gid_;
std::vector<gid_t> supp_gids_;
CapSet capabilities_;
unsigned namespace_flags_;
std::string seclabel_;
std::vector<SocketInfo> sockets_;
std::vector<ServiceEnvironmentInfo> envvars_;
Action onrestart_; // Commands to execute on restart.
std::vector<std::string> writepid_files_;
// keycodes for triggering this service via /dev/keychord
std::vector<int> keycodes_;
int keychord_id_;
IoSchedClass ioprio_class_;
int ioprio_pri_;
int priority_;
int oom_score_adjust_;
std::vector<std::string> args_;
};
class ServiceManager {
public:
static ServiceManager& GetInstance();
void AddService(std::unique_ptr<Service> service);
Service* MakeExecOneshotService(const std::vector<std::string>& args);
Service* FindServiceByName(const std::string& name) const;
Service* FindServiceByPid(pid_t pid) const;
Service* FindServiceByKeychord(int keychord_id) const;
void ForEachService(const std::function<void(Service*)>& callback) const;
void ForEachServiceInClass(const std::string& classname,
void (*func)(Service* svc)) const;
void ForEachServiceWithFlags(unsigned matchflags,
void (*func)(Service* svc)) const;
void ReapAnyOutstandingChildren();
void RemoveService(const Service& svc);
void DumpState() const;
private:
ServiceManager();
// Cleans up a child process that exited.
// Returns true iff a children was cleaned up.
bool ReapOneProcess();
static int exec_count_; // Every service needs a unique name.
std::vector<std::unique_ptr<Service>> services_;
};
class ServiceParser : public SectionParser {
public:
ServiceParser() : service_(nullptr) {
}
bool ParseSection(const std::vector<std::string>& args,
std::string* err) override;
bool ParseLineSection(const std::vector<std::string>& args,
const std::string& filename, int line,
std::string* err) const override;
void EndSection() override;
void EndFile(const std::string&) override {
}
private:
bool IsValidName(const std::string& name) const;
std::unique_ptr<Service> service_;
};
#endif
Reference in a new issue View git blame Copy permalink