3a2dc8382a
2.6.36 introduced the abilitiy to specify the task that is having its rlimits set. Update mediation to ensure that confined tasks can only set their own group_leader as expected by current policy. Add TODO note about extending policy to support setting other tasks rlimits. Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: James Morris <jmorris@namei.org>
139 lines
3.9 KiB
C
139 lines
3.9 KiB
C
/*
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* AppArmor security module
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*
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* This file contains AppArmor resource mediation and attachment
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*
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* Copyright (C) 1998-2008 Novell/SUSE
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* Copyright 2009-2010 Canonical Ltd.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2 of the
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* License.
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*/
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#include <linux/audit.h>
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#include "include/audit.h"
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#include "include/resource.h"
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#include "include/policy.h"
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/*
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* Table of rlimit names: we generate it from resource.h.
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*/
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#include "rlim_names.h"
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/* audit callback for resource specific fields */
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static void audit_cb(struct audit_buffer *ab, void *va)
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{
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struct common_audit_data *sa = va;
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audit_log_format(ab, " rlimit=%s value=%lu",
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rlim_names[sa->aad.rlim.rlim], sa->aad.rlim.max);
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}
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/**
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* audit_resource - audit setting resource limit
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* @profile: profile being enforced (NOT NULL)
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* @resoure: rlimit being auditing
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* @value: value being set
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* @error: error value
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*
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* Returns: 0 or sa->error else other error code on failure
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*/
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static int audit_resource(struct aa_profile *profile, unsigned int resource,
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unsigned long value, int error)
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{
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struct common_audit_data sa;
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COMMON_AUDIT_DATA_INIT(&sa, NONE);
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sa.aad.op = OP_SETRLIMIT,
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sa.aad.rlim.rlim = resource;
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sa.aad.rlim.max = value;
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sa.aad.error = error;
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return aa_audit(AUDIT_APPARMOR_AUTO, profile, GFP_KERNEL, &sa,
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audit_cb);
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}
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/**
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* aa_map_resouce - map compiled policy resource to internal #
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* @resource: flattened policy resource number
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*
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* Returns: resource # for the current architecture.
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*
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* rlimit resource can vary based on architecture, map the compiled policy
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* resource # to the internal representation for the architecture.
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*/
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int aa_map_resource(int resource)
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{
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return rlim_map[resource];
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}
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/**
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* aa_task_setrlimit - test permission to set an rlimit
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* @profile - profile confining the task (NOT NULL)
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* @task - task the resource is being set on
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* @resource - the resource being set
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* @new_rlim - the new resource limit (NOT NULL)
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*
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* Control raising the processes hard limit.
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*
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* Returns: 0 or error code if setting resource failed
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*/
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int aa_task_setrlimit(struct aa_profile *profile, struct task_struct *task,
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unsigned int resource, struct rlimit *new_rlim)
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{
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int error = 0;
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/* TODO: extend resource control to handle other (non current)
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* processes. AppArmor rules currently have the implicit assumption
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* that the task is setting the resource of the current process
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*/
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if ((task != current->group_leader) ||
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(profile->rlimits.mask & (1 << resource) &&
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new_rlim->rlim_max > profile->rlimits.limits[resource].rlim_max))
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error = -EACCES;
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return audit_resource(profile, resource, new_rlim->rlim_max, error);
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}
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/**
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* __aa_transition_rlimits - apply new profile rlimits
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* @old: old profile on task (NOT NULL)
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* @new: new profile with rlimits to apply (NOT NULL)
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*/
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void __aa_transition_rlimits(struct aa_profile *old, struct aa_profile *new)
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{
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unsigned int mask = 0;
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struct rlimit *rlim, *initrlim;
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int i;
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/* for any rlimits the profile controlled reset the soft limit
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* to the less of the tasks hard limit and the init tasks soft limit
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*/
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if (old->rlimits.mask) {
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for (i = 0, mask = 1; i < RLIM_NLIMITS; i++, mask <<= 1) {
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if (old->rlimits.mask & mask) {
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rlim = current->signal->rlim + i;
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initrlim = init_task.signal->rlim + i;
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rlim->rlim_cur = min(rlim->rlim_max,
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initrlim->rlim_cur);
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}
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}
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}
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/* set any new hard limits as dictated by the new profile */
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if (!new->rlimits.mask)
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return;
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for (i = 0, mask = 1; i < RLIM_NLIMITS; i++, mask <<= 1) {
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if (!(new->rlimits.mask & mask))
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continue;
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rlim = current->signal->rlim + i;
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rlim->rlim_max = min(rlim->rlim_max,
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new->rlimits.limits[i].rlim_max);
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/* soft limit should not exceed hard limit */
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rlim->rlim_cur = min(rlim->rlim_cur, rlim->rlim_max);
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}
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}
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