security/apparmor/secid.c

Source file repositories/reference/linux-study-clean/security/apparmor/secid.c

File Facts

System
Linux kernel
Corpus path
security/apparmor/secid.c
Extension
.c
Size
3398 bytes
Lines
156
Domain
Core OS
Bucket
Security And Isolation
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only
/*
 * AppArmor security module
 *
 * This file contains AppArmor security identifier (secid) manipulation fns
 *
 * Copyright 2009-2017 Canonical Ltd.
 *
 * 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/slab.h>
#include <linux/spinlock.h>
#include <linux/xarray.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 2

static DEFINE_XARRAY_FLAGS(aa_secids, XA_FLAGS_LOCK_IRQ | XA_FLAGS_TRACK_FREE);

int apparmor_display_secid_mode;

/*
 * TODO: allow policy to reserve a secid range?
 * TODO: add secid pinning
 * TODO: use secid_update in label replace
 */

/*
 * see label for inverse aa_label_to_secid
 */
struct aa_label *aa_secid_to_label(u32 secid)
{
	return xa_load(&aa_secids, secid);
}

static int apparmor_label_to_secctx(struct aa_label *label,
				    struct lsm_context *cp)
{
	/* TODO: cache secctx and ref count so we don't have to recreate */
	int flags = FLAG_VIEW_SUBNS | FLAG_HIDDEN_UNCONFINED | FLAG_ABS_ROOT;
	int len;

	if (!label)
		return -EINVAL;

	if (apparmor_display_secid_mode)
		flags |= FLAG_SHOW_MODE;

	if (cp)
		len = aa_label_asxprint(&cp->context, root_ns, label,
					flags, GFP_ATOMIC);
	else
		len = aa_label_snxprint(NULL, 0, root_ns, label, flags);

	if (len < 0)
		return -ENOMEM;

	if (cp) {
		cp->len = len;
		cp->id = LSM_ID_APPARMOR;
	}

	return len;
}

int apparmor_secid_to_secctx(u32 secid, struct lsm_context *cp)
{
	struct aa_label *label = aa_secid_to_label(secid);

	return apparmor_label_to_secctx(label, cp);
}

int apparmor_lsmprop_to_secctx(struct lsm_prop *prop, struct lsm_context *cp)
{
	struct aa_label *label;

Annotation

Implementation Notes