/* * linux/kernel/capability.c * * Copyright (C) 1997  Andrew Main <zefram@fysh.org> * * Integrated into 2.1.97+,  Andrew G. Morgan <morgan@kernel.org> * 30 May 2002:	Cleanup, Robert M. Love <rml@tech9.net> */ #include <linux/capability.h>#include <linux/mm.h>#include <linux/module.h>#include <linux/security.h>#include <linux/syscalls.h>#include <linux/pid_namespace.h>#include <asm/uaccess.h> /* * This lock protects task->cap_* for all tasks including current. * Locking rule: acquire this prior to tasklist_lock. */static DEFINE_SPINLOCK(task_capability_lock); /* * For sys_getproccap() and sys_setproccap(), any of the three * capability set pointers may be NULL -- indicating that that set is * uninteresting and/or not to be changed. */ /** * sys_capget - get the capabilities of a given process. * @header: pointer to struct that contains capability version and *	target pid data * @dataptr: pointer to struct that contains the effective, permitted, *	and inheritable capabilities that are returned * * Returns 0 on success and < 0 on error. */asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr){	int ret = 0;	pid_t pid;	__u32 version;	struct task_struct *target;	struct __user_cap_data_struct data; 	if (get_user(version, &header->version))		return -EFAULT; 	if (version != _LINUX_CAPABILITY_VERSION) {		if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))			return -EFAULT;		return -EINVAL;	} 	if (get_user(pid, &header->pid))		return -EFAULT; 	if (pid < 0)		return -EINVAL; 	spin_lock(&task_capability_lock);	read_lock(&tasklist_lock); 	if (pid && pid != task_pid_vnr(current)) {		target = find_task_by_vpid(pid);		if (!target) {			ret = -ESRCH;			goto out;		}	} else		target = current; 	ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted); out:	read_unlock(&tasklist_lock);	spin_unlock(&task_capability_lock); 	if (!ret && copy_to_user(dataptr, &data, sizeof data))		return -EFAULT; 	return ret;} /* * cap_set_pg - set capabilities for all processes in a given process * group.  We call this holding task_capability_lock and tasklist_lock. */static inline int cap_set_pg(int pgrp_nr, kernel_cap_t *effective,			      kernel_cap_t *inheritable,			      kernel_cap_t *permitted){	struct task_struct *g, *target;	int ret = -EPERM;	int found = 0;	struct pid *pgrp; 	pgrp = find_vpid(pgrp_nr);	do_each_pid_task(pgrp, PIDTYPE_PGID, g) {		target = g;		while_each_thread(g, target) {			if (!security_capset_check(target, effective,							inheritable,							permitted)) {				security_capset_set(target, effective,							inheritable,							permitted);				ret = 0;			}			found = 1;		}	} while_each_pid_task(pgrp, PIDTYPE_PGID, g); 	if (!found)		ret = 0;	return ret;} /* * cap_set_all - set capabilities for all processes other than init * and self.  We call this holding task_capability_lock and tasklist_lock. */static inline int cap_set_all(kernel_cap_t *effective,			       kernel_cap_t *inheritable,			       kernel_cap_t *permitted){     struct task_struct *g, *target;     int ret = -EPERM;     int found = 0;      do_each_thread(g, target) {             if (target == current || is_container_init(target->group_leader))                     continue;             found = 1;	     if (security_capset_check(target, effective, inheritable,						permitted))		     continue;	     ret = 0;	     security_capset_set(target, effective, inheritable, permitted);     } while_each_thread(g, target);      if (!found)	     ret = 0;     return ret;} /** * sys_capset - set capabilities for a process or a group of processes * @header: pointer to struct that contains capability version and *	target pid data * @data: pointer to struct that contains the effective, permitted, *	and inheritable capabilities * * Set capabilities for a given process, all processes, or all * processes in a given process group. * * The restrictions on setting capabilities are specified as: * * [pid is for the 'target' task.  'current' is the calling task.] * * I: any raised capabilities must be a subset of the (old current) permitted * P: any raised capabilities must be a subset of the (old current) permitted * E: must be set to a subset of (new target) permitted * * Returns 0 on success and < 0 on error. */asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data){	kernel_cap_t inheritable, permitted, effective;	__u32 version;	struct task_struct *target;	int ret;	pid_t pid; 	if (get_user(version, &header->version))		return -EFAULT; 	if (version != _LINUX_CAPABILITY_VERSION) {		if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))			return -EFAULT;		return -EINVAL;	} 	if (get_user(pid, &header->pid))		return -EFAULT; 	if (pid && pid != task_pid_vnr(current) && !capable(CAP_SETPCAP))		return -EPERM; 	if (copy_from_user(&effective, &data->effective, sizeof(effective)) ||	    copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) ||	    copy_from_user(&permitted, &data->permitted, sizeof(permitted)))		return -EFAULT; 	spin_lock(&task_capability_lock);	read_lock(&tasklist_lock); 	if (pid > 0 && pid != task_pid_vnr(current)) {		target = find_task_by_vpid(pid);		if (!target) {			ret = -ESRCH;			goto out;		}	} else		target = current; 	ret = 0; 	/* having verified that the proposed changes are legal,	   we now put them into effect. */	if (pid < 0) {		if (pid == -1)	/* all procs other than current and init */			ret = cap_set_all(&effective, &inheritable, &permitted); 		else		/* all procs in process group */			ret = cap_set_pg(-pid, &effective, &inheritable,					 &permitted);	} else {		ret = security_capset_check(target, &effective, &inheritable,					    &permitted);		if (!ret)			security_capset_set(target, &effective, &inheritable,					    &permitted);	} out:	read_unlock(&tasklist_lock);	spin_unlock(&task_capability_lock); 	return ret;} int __capable(struct task_struct *t, int cap){	if (security_capable(t, cap) == 0) {		t->flags |= PF_SUPERPRIV;		return 1;	}	return 0;} int capable(int cap){	return __capable(current, cap);}EXPORT_SYMBOL(capable);