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/*
* 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 <linux/security.h>
#include "include/audit.h"
#include "include/cred.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_sfs_entry aa_sfs_entry_rlimit[] = {
AA_SFS_FILE_STRING("mask", AA_SFS_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[aad(sa)->rlim.rlim], aad(sa)->rlim.max);
if (aad(sa)->peer) {
audit_log_format(ab, " peer=");
aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer,
FLAGS_NONE, GFP_ATOMIC);
}
}
/**
* audit_resource - audit setting resource limit
* @profile: profile being enforced (NOT NULL)
* @resource: 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, struct aa_label *peer,
const char *info, int error)
{
DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_SETRLIMIT);
aad(&sa)->rlim.rlim = resource;
aad(&sa)->rlim.max = value;
aad(&sa)->peer = peer;
aad(&sa)->info = info;
aad(&sa)->error = error;
return aa_audit(AUDIT_APPARMOR_AUTO, profile, &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];
}
static int profile_setrlimit(struct aa_profile *profile, unsigned int resource,
struct rlimit *new_rlim)
{
int e = 0;
if (profile->rlimits.mask & (1 << resource) && new_rlim->rlim_max >
profile->rlimits.limits[resource].rlim_max)
e = -EACCES;
return audit_resource(profile, resource, new_rlim->rlim_max, NULL, NULL,
e);
}
/**
* aa_task_setrlimit - test permission to set an rlimit
* @label - label 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_label *label, struct task_struct *task,
unsigned int resource, struct rlimit *new_rlim)
{
struct aa_profile *profile;
struct aa_label *peer;
int error = 0;
rcu_read_lock();
peer = aa_get_newest_cred_label(__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 or that the task setting the resource of another
* task has CAP_SYS_RESOURCE.
*/
if (label != peer &&
aa_capable(label, CAP_SYS_RESOURCE, SECURITY_CAP_NOAUDIT) != 0)
error = fn_for_each(label, profile,
audit_resource(profile, resource,
new_rlim->rlim_max, peer,
"cap_sys_resource", -EACCES));
else
error = fn_for_each_confined(label, profile,
profile_setrlimit(profile, resource, new_rlim));
aa_put_label(peer);
return error;
}
/**
* __aa_transition_rlimits - apply new profile rlimits
* @old_l: old label on task (NOT NULL)
* @new_l: new label with rlimits to apply (NOT NULL)
*/
void __aa_transition_rlimits(struct aa_label *old_l, struct aa_label *new_l)
{
unsigned int mask = 0;
struct rlimit *rlim, *initrlim;
struct aa_profile *old, *new;
struct label_it i;
old = labels_profile(old_l);
new = labels_profile(new_l);
/* for any rlimits the profile controlled, reset the soft limit
* to the lesser of the tasks hard limit and the init tasks soft limit
*/
label_for_each_confined(i, old_l, old) {
if (old->rlimits.mask) {
int j;
for (j = 0, mask = 1; j < RLIM_NLIMITS; j++,
mask <<= 1) {
if (old->rlimits.mask & mask) {
rlim = current->signal->rlim + j;
initrlim = init_task.signal->rlim + j;
rlim->rlim_cur = min(rlim->rlim_max,
initrlim->rlim_cur);
}
}
}
}
/* set any new hard limits as dictated by the new profile */
label_for_each_confined(i, new_l, new) {
int j;
if (!new->rlimits.mask)
continue;
for (j = 0, mask = 1; j < RLIM_NLIMITS; j++, mask <<= 1) {
if (!(new->rlimits.mask & mask))
continue;
rlim = current->signal->rlim + j;
rlim->rlim_max = min(rlim->rlim_max,
new->rlimits.limits[j].rlim_max);
/* soft limit should not exceed hard limit */
rlim->rlim_cur = min(rlim->rlim_cur, rlim->rlim_max);
}
}
}
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