a4c3f89c9b
The IDR conversion did not handle an error case for when allocating a
mapping fails, and it did not ensure that mappings did not allocate or
use a 0 value, which is used as an invalid secid. Which is used when a
mapping fails.
Fixes: 3ae7eb49a2be ("apparmor: Use an IDR to allocate apparmor secids")
Signed-off-by: John Johansen <john.johansen@canonical.com>
168 lines
3.6 KiB
C
168 lines
3.6 KiB
C
/*
|
|
* 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
|
|
*/
|
|
|
|
#define AA_FIRST_SECID 1
|
|
|
|
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
|
|
* @label: the label to allocate a secid for
|
|
* @gfp: memory allocation flags
|
|
*
|
|
* Returns: 0 with @label->secid initialized
|
|
* <0 returns error with @label->secid set to AA_SECID_INVALID
|
|
*/
|
|
int aa_alloc_secid(struct aa_label *label, gfp_t gfp)
|
|
{
|
|
unsigned long flags;
|
|
int ret;
|
|
|
|
idr_preload(gfp);
|
|
spin_lock_irqsave(&secid_lock, flags);
|
|
ret = idr_alloc(&aa_secids, label, AA_FIRST_SECID, 0, GFP_ATOMIC);
|
|
spin_unlock_irqrestore(&secid_lock, flags);
|
|
idr_preload_end();
|
|
|
|
if (ret < 0) {
|
|
label->secid = AA_SECID_INVALID;
|
|
return ret;
|
|
}
|
|
|
|
AA_BUG(ret == AA_SECID_INVALID);
|
|
label->secid = ret;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* 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);
|
|
}
|
|
|
|
void aa_secids_init(void)
|
|
{
|
|
idr_init_base(&aa_secids, AA_FIRST_SECID);
|
|
}
|