/*
   * AppArmor security module
   *
   * This file contains AppArmor resource mediation and attachment
   *
   * Copyright (C) 1998-2008 Novell/SUSE
   * Copyright 2009-2010 Canonical Ltd.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License as
   * published by the Free Software Foundation, version 2 of the
   * License.
   */
  
  #include <linux/audit.h>
  
  #include "include/audit.h"
  #include "include/context.h"
  #include "include/resource.h"
  #include "include/policy.h"
  
  /*
   * Table of rlimit names: we generate it from resource.h.
   */
  #include "rlim_names.h"
  
  struct aa_fs_entry aa_fs_entry_rlimit[] = {
  	AA_FS_FILE_STRING("mask", AA_FS_RLIMIT_MASK),
  	{ }
  };
  
  /* audit callback for resource specific fields */
  static void audit_cb(struct audit_buffer *ab, void *va)
  {
  	struct common_audit_data *sa = va;
  
  	audit_log_format(ab, " rlimit=%s value=%lu",
  			 rlim_names[sa->aad->rlim.rlim], sa->aad->rlim.max);
  }
  
  /**
   * audit_resource - audit setting resource limit
   * @profile: profile being enforced  (NOT NULL)
   * @resoure: rlimit being auditing
   * @value: value being set
   * @error: error value
   *
   * Returns: 0 or sa->error else other error code on failure
   */
  static int audit_resource(struct aa_profile *profile, unsigned int resource,
  			  unsigned long value, int error)
  {
  	struct common_audit_data sa;
  	struct apparmor_audit_data aad = {0,};
  
  	sa.type = LSM_AUDIT_DATA_NONE;
  	sa.aad = &aad;
  	aad.op = OP_SETRLIMIT,
  	aad.rlim.rlim = resource;
  	aad.rlim.max = value;
  	aad.error = error;
  	return aa_audit(AUDIT_APPARMOR_AUTO, profile, GFP_KERNEL, &sa,
  			audit_cb);
  }
  
  /**
   * aa_map_resouce - map compiled policy resource to internal #
   * @resource: flattened policy resource number
   *
   * Returns: resource # for the current architecture.
   *
   * rlimit resource can vary based on architecture, map the compiled policy
   * resource # to the internal representation for the architecture.
   */
  int aa_map_resource(int resource)
  {
  	return rlim_map[resource];
  }
  
  /**
   * aa_task_setrlimit - test permission to set an rlimit
   * @profile - profile confining the task  (NOT NULL)
   * @task - task the resource is being set on
   * @resource - the resource being set
   * @new_rlim - the new resource limit  (NOT NULL)
   *
   * Control raising the processes hard limit.
   *
   * Returns: 0 or error code if setting resource failed
   */
  int aa_task_setrlimit(struct aa_profile *profile, struct task_struct *task,
  		      unsigned int resource, struct rlimit *new_rlim)
  {
  	struct aa_profile *task_profile;
  	int error = 0;
  
  	rcu_read_lock();
  	task_profile = aa_get_profile(aa_cred_profile(__task_cred(task)));
  	rcu_read_unlock();
  
  	/* TODO: extend resource control to handle other (non current)
  	 * profiles.  AppArmor rules currently have the implicit assumption
  	 * that the task is setting the resource of a task confined with
  	 * the same profile.
  	 */
  	if (profile != task_profile ||
  	    (profile->rlimits.mask & (1 << resource) &&
  	     new_rlim->rlim_max > profile->rlimits.limits[resource].rlim_max))
  		error = -EACCES;
  
  	aa_put_profile(task_profile);
  
  	return audit_resource(profile, resource, new_rlim->rlim_max, error);
  }
  
  /**
   * __aa_transition_rlimits - apply new profile rlimits
   * @old: old profile on task  (NOT NULL)
   * @new: new profile with rlimits to apply  (NOT NULL)
   */
  void __aa_transition_rlimits(struct aa_profile *old, struct aa_profile *new)
  {
  	unsigned int mask = 0;
  	struct rlimit *rlim, *initrlim;
  	int i;
  
  	/* for any rlimits the profile controlled reset the soft limit
  	 * to the less of the tasks hard limit and the init tasks soft limit
  	 */
  	if (old->rlimits.mask) {
  		for (i = 0, mask = 1; i < RLIM_NLIMITS; i++, mask <<= 1) {
  			if (old->rlimits.mask & mask) {
  				rlim = current->signal->rlim + i;
  				initrlim = init_task.signal->rlim + i;
  				rlim->rlim_cur = min(rlim->rlim_max,
  						     initrlim->rlim_cur);
  			}
  		}
  	}
  
  	/* set any new hard limits as dictated by the new profile */
  	if (!new->rlimits.mask)
  		return;
  	for (i = 0, mask = 1; i < RLIM_NLIMITS; i++, mask <<= 1) {
  		if (!(new->rlimits.mask & mask))
  			continue;
  
  		rlim = current->signal->rlim + i;
  		rlim->rlim_max = min(rlim->rlim_max,
  				     new->rlimits.limits[i].rlim_max);
  		/* soft limit should not exceed hard limit */
  		rlim->rlim_cur = min(rlim->rlim_cur, rlim->rlim_max);
  	}
  }