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/*
* AppArmor security module
*
* This file contains AppArmor security identifier (secid) manipulation fns
*
* Copyright 2009-2017 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.
*
*
* AppArmor allocates a unique secid for every label used. If a label
* is replaced it receives the secid of the label it is replacing.
*/
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/gfp.h>
#include <linux/idr.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include "include/cred.h"
#include "include/lib.h"
#include "include/secid.h"
#include "include/label.h"
#include "include/policy_ns.h"
/*
* secids - do not pin labels with a refcount. They rely on the label
* properly updating/freeing them
*/
static DEFINE_IDR(aa_secids);
static DEFINE_SPINLOCK(secid_lock);
/*
* TODO: allow policy to reserve a secid range?
* TODO: add secid pinning
* TODO: use secid_update in label replace
*/
/**
* aa_secid_update - update a secid mapping to a new label
* @secid: secid to update
* @label: label the secid will now map to
*/
void aa_secid_update(u32 secid, struct aa_label *label)
{
unsigned long flags;
spin_lock_irqsave(&secid_lock, flags);
idr_replace(&aa_secids, label, secid);
spin_unlock_irqrestore(&secid_lock, flags);
}
/**
*
* see label for inverse aa_label_to_secid
*/
struct aa_label *aa_secid_to_label(u32 secid)
{
struct aa_label *label;
rcu_read_lock();
label = idr_find(&aa_secids, secid);
rcu_read_unlock();
return label;
}
int apparmor_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
{
/* TODO: cache secctx and ref count so we don't have to recreate */
struct aa_label *label = aa_secid_to_label(secid);
int len;
AA_BUG(!secdata);
AA_BUG(!seclen);
if (!label)
return -EINVAL;
if (secdata)
len = aa_label_asxprint(secdata, root_ns, label,
FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
FLAG_HIDDEN_UNCONFINED | FLAG_ABS_ROOT,
GFP_ATOMIC);
else
len = aa_label_snxprint(NULL, 0, root_ns, label,
FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
FLAG_HIDDEN_UNCONFINED | FLAG_ABS_ROOT);
if (len < 0)
return -ENOMEM;
*seclen = len;
return 0;
}
int apparmor_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
{
struct aa_label *label;
label = aa_label_strn_parse(&root_ns->unconfined->label, secdata,
seclen, GFP_KERNEL, false, false);
if (IS_ERR(label))
return PTR_ERR(label);
*secid = label->secid;
return 0;
}
void apparmor_release_secctx(char *secdata, u32 seclen)
{
kfree(secdata);
}
/**
* aa_alloc_secid - allocate a new secid for a profile
*/
u32 aa_alloc_secid(struct aa_label *label, gfp_t gfp)
{
unsigned long flags;
u32 secid;
idr_preload(gfp);
spin_lock_irqsave(&secid_lock, flags);
secid = idr_alloc(&aa_secids, label, 0, 0, GFP_ATOMIC);
/* XXX: Can return -ENOMEM */
spin_unlock_irqrestore(&secid_lock, flags);
idr_preload_end();
return secid;
}
/**
* aa_free_secid - free a secid
* @secid: secid to free
*/
void aa_free_secid(u32 secid)
{
unsigned long flags;
spin_lock_irqsave(&secid_lock, flags);
idr_remove(&aa_secids, secid);
spin_unlock_irqrestore(&secid_lock, flags);
}
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