168 lines
3.6 KiB
C
168 lines
3.6 KiB
C
/*
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* AppArmor security module
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*
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* This file contains AppArmor security identifier (secid) manipulation fns
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*
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* Copyright 2009-2017 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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*
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* AppArmor allocates a unique secid for every label used. If a label
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* is replaced it receives the secid of the label it is replacing.
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*/
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#include <linux/errno.h>
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#include <linux/err.h>
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#include <linux/gfp.h>
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#include <linux/idr.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include "include/cred.h"
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#include "include/lib.h"
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#include "include/secid.h"
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#include "include/label.h"
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#include "include/policy_ns.h"
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/*
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* secids - do not pin labels with a refcount. They rely on the label
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* properly updating/freeing them
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*/
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#define AA_FIRST_SECID 1
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static DEFINE_IDR(aa_secids);
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static DEFINE_SPINLOCK(secid_lock);
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/*
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* TODO: allow policy to reserve a secid range?
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* TODO: add secid pinning
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* TODO: use secid_update in label replace
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*/
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/**
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* aa_secid_update - update a secid mapping to a new label
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* @secid: secid to update
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* @label: label the secid will now map to
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*/
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void aa_secid_update(u32 secid, struct aa_label *label)
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{
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unsigned long flags;
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spin_lock_irqsave(&secid_lock, flags);
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idr_replace(&aa_secids, label, secid);
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spin_unlock_irqrestore(&secid_lock, flags);
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}
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/**
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*
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* see label for inverse aa_label_to_secid
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*/
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struct aa_label *aa_secid_to_label(u32 secid)
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{
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struct aa_label *label;
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rcu_read_lock();
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label = idr_find(&aa_secids, secid);
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rcu_read_unlock();
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return label;
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}
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int apparmor_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
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{
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/* TODO: cache secctx and ref count so we don't have to recreate */
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struct aa_label *label = aa_secid_to_label(secid);
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int len;
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AA_BUG(!seclen);
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if (!label)
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return -EINVAL;
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if (secdata)
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len = aa_label_asxprint(secdata, root_ns, label,
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FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
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FLAG_HIDDEN_UNCONFINED | FLAG_ABS_ROOT,
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GFP_ATOMIC);
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else
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len = aa_label_snxprint(NULL, 0, root_ns, label,
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FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
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FLAG_HIDDEN_UNCONFINED | FLAG_ABS_ROOT);
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if (len < 0)
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return -ENOMEM;
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*seclen = len;
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return 0;
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}
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int apparmor_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
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{
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struct aa_label *label;
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label = aa_label_strn_parse(&root_ns->unconfined->label, secdata,
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seclen, GFP_KERNEL, false, false);
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if (IS_ERR(label))
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return PTR_ERR(label);
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*secid = label->secid;
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return 0;
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}
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void apparmor_release_secctx(char *secdata, u32 seclen)
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{
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kfree(secdata);
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}
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/**
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* aa_alloc_secid - allocate a new secid for a profile
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* @label: the label to allocate a secid for
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* @gfp: memory allocation flags
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*
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* Returns: 0 with @label->secid initialized
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* <0 returns error with @label->secid set to AA_SECID_INVALID
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*/
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int aa_alloc_secid(struct aa_label *label, gfp_t gfp)
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{
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unsigned long flags;
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int ret;
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idr_preload(gfp);
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spin_lock_irqsave(&secid_lock, flags);
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ret = idr_alloc(&aa_secids, label, AA_FIRST_SECID, 0, GFP_ATOMIC);
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spin_unlock_irqrestore(&secid_lock, flags);
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idr_preload_end();
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if (ret < 0) {
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label->secid = AA_SECID_INVALID;
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return ret;
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}
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AA_BUG(ret == AA_SECID_INVALID);
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label->secid = ret;
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return 0;
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}
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/**
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* aa_free_secid - free a secid
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* @secid: secid to free
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*/
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void aa_free_secid(u32 secid)
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{
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unsigned long flags;
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spin_lock_irqsave(&secid_lock, flags);
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idr_remove(&aa_secids, secid);
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spin_unlock_irqrestore(&secid_lock, flags);
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}
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void aa_secids_init(void)
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{
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idr_init_base(&aa_secids, AA_FIRST_SECID);
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}
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