userns: Allow unprivileged reboot (923c7538) · Commits · 戴 / test

In a container with its own pid namespace and user namespace, rebooting the system won't reboot the host, but terminate all the processes in it and thus have the container shutdown, so it's safe. Signed-off-by:

Li Zefan <lizefan@huawei.com> Signed-off-by:

Eric W. Biederman <ebiederm@xmission.com>

kernel/sys.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -433,11 +433,12 @@ static DEFINE_MUTEX(reboot_mutex);
		SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
		void __user *, arg)
		{
		struct pid_namespace *pid_ns = task_active_pid_ns(current);
		char buffer[256];
		int ret = 0;

		/* We only trust the superuser with rebooting the system. */
		if (!capable(CAP_SYS_BOOT))
		if (!ns_capable(pid_ns->user_ns, CAP_SYS_BOOT))
		return -EPERM;

		/* For safety, we require "magic" arguments. */
		@@ -453,7 +454,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
		* pid_namespace, the command is handled by reboot_pid_ns() which will
		* call do_exit().
		*/
		ret = reboot_pid_ns(task_active_pid_ns(current), cmd);
		ret = reboot_pid_ns(pid_ns, cmd);
		if (ret)
		return ret;

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