| // Copyright 2015 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef SANDBOX_LINUX_SERVICES_NAMESPACE_SANDBOX_H_ |
| #define SANDBOX_LINUX_SERVICES_NAMESPACE_SANDBOX_H_ |
| |
| #include <sys/types.h> |
| |
| #include <string> |
| #include <vector> |
| |
| #include "base/command_line.h" |
| #include "base/macros.h" |
| #include "base/process/launch.h" |
| #include "base/process/process.h" |
| #include "sandbox/sandbox_export.h" |
| |
| namespace sandbox { |
| |
| // Helper class for starting a process inside a new user, PID, and network |
| // namespace. Before using a namespace sandbox, check for namespaces support |
| // using Credentials::CanCreateProcessInNewUserNS. |
| // |
| // A typical use for "A" launching a sandboxed process "B" would be: |
| // 1. A sets up a command line and launch options for process B. |
| // 2. A launches B with LaunchProcess. |
| // 3. B should be prepared to assume the role of init(1). In particular, apart |
| // from SIGKILL and SIGSTOP, B cannot receive any signal for which it does |
| // not have an explicit signal handler registered. |
| // If B dies, all the processes in the namespace will die. |
| // B can fork() and the parent can assume the role of init(1), by using |
| // CreateInitProcessReaper(). |
| // 4. B chroots using Credentials::MoveToNewUserNS() and |
| // Credentials::DropFileSystemAccess() |
| // 5. B drops capabilities gained by entering the new user namespace with |
| // Credentials::DropAllCapabilities(). |
| class SANDBOX_EXPORT NamespaceSandbox { |
| public: |
| #if !defined(OS_NACL_NONSFI) |
| struct Options { |
| Options(); |
| ~Options(); |
| |
| // Bitmask of namespace types. Must be some combination of CLONE_NEWUSER |
| // (required), CLONE_NEWPID, and CLONE_NEWNET. Defaults to all of the above. |
| int ns_types; |
| |
| // Fail if any of the namespace types are not supported. Defaults to false. |
| bool fail_on_unsupported_ns_type; |
| }; |
| |
| // Launch a new process inside its own user/PID/network namespaces (depending |
| // on kernel support). Requires at a minimum that user namespaces are |
| // supported (use Credentials::CanCreateProcessInNewUserNS to check this). |
| // |
| // pre_exec_delegate and clone_flags fields of LaunchOptions should be nullptr |
| // and 0, respectively, since this function makes a copy of options and |
| // overrides them. |
| static base::Process LaunchProcess(const base::CommandLine& cmdline, |
| const base::LaunchOptions& launch_options); |
| static base::Process LaunchProcess(const std::vector<std::string>& argv, |
| const base::LaunchOptions& launch_options); |
| |
| // Versions which take namespace sandbox options. These allow fine grained |
| // control over the types of namespaces used. |
| static base::Process LaunchProcessWithOptions( |
| const base::CommandLine& cmdline, |
| const base::LaunchOptions& launch_options, |
| const Options& ns_sandbox_options); |
| static base::Process LaunchProcessWithOptions( |
| const std::vector<std::string>& argv, |
| const base::LaunchOptions& launch_options, |
| const Options& ns_sandbox_options); |
| #endif // !defined(OS_NACL_NONSFI) |
| |
| // Forks a process in its own PID namespace. The child process is the init |
| // process inside of the PID namespace, so if the child needs to fork further, |
| // it should call CreateInitProcessReaper, which turns the init process into a |
| // reaper process. |
| // |
| // Otherwise, the child should setup handlers for signals which should |
| // terminate the process using InstallDefaultTerminationSignalHandlers or |
| // InstallTerminationSignalHandler. This works around the fact that init |
| // processes ignore such signals unless they have an explicit handler set. |
| // |
| // This function requries CAP_SYS_ADMIN. If |drop_capabilities_in_child| is |
| // true, then capabilities are dropped in the child. |
| static pid_t ForkInNewPidNamespace(bool drop_capabilities_in_child); |
| |
| // Installs a signal handler for: |
| // |
| // SIGHUP, SIGINT, SIGABRT, SIGQUIT, SIGPIPE, SIGTERM, SIGUSR1, SIGUSR2 |
| // |
| // that exits with SignalExitCode(sig). These are signals whose default action |
| // is to terminate the program (apart from SIGILL, SIGFPE, and SIGSEGV, which |
| // will still terminate the process if e.g. an illegal instruction is |
| // encountered, etc.). |
| // |
| // If any of these already had a signal handler installed, this function will |
| // not override them. |
| static void InstallDefaultTerminationSignalHandlers(); |
| |
| // Installs a signal handler for |sig| which exits with |exit_code|. If a |
| // signal handler was already present for |sig|, does nothing and returns |
| // false. |
| static bool InstallTerminationSignalHandler(int sig, int exit_code); |
| |
| // Returns an exit code corresponding to the process being killed by sig. This |
| // is the same as exit code that NaCl's default signal handler uses. |
| static int SignalExitCode(int sig) { return -sig & 0xff; } |
| |
| // Returns whether the namespace sandbox created a new user, PID, and network |
| // namespace. In particular, InNewUserNamespace should return true iff the |
| // process was started via this class. |
| static bool InNewUserNamespace(); |
| static bool InNewPidNamespace(); |
| static bool InNewNetNamespace(); |
| |
| private: |
| DISALLOW_IMPLICIT_CONSTRUCTORS(NamespaceSandbox); |
| }; |
| |
| } // namespace sandbox |
| |
| #endif // SANDBOX_LINUX_SERVICES_NAMESPACE_SANDBOX_H_ |