path: root/security/apparmor/lsm.c

/*
 * AppArmor security module
 *
 * This file contains AppArmor LSM hooks.
 *
 * Copyright (C) 1998-2008 Novell/SUSE
 * Copyright 2009-2010 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.
 */

#include <linux/security.h>
#include <linux/moduleparam.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/ptrace.h>
#include <linux/ctype.h>
#include <linux/sysctl.h>
#include <linux/audit.h>
#include <linux/user_namespace.h>
#include <net/sock.h>

#include "include/apparmor.h"
#include "include/apparmorfs.h"
#include "include/audit.h"
#include "include/capability.h"
#include "include/context.h"
#include "include/file.h"
#include "include/ipc.h"
#include "include/path.h"
#include "include/policy.h"
#include "include/procattr.h"

/* Flag indicating whether initialization completed */
int apparmor_initialized __initdata;

/*
 * LSM hook functions
 */

/*
 * free the associated aa_task_cxt and put its profiles
 */
static void apparmor_cred_free(struct cred *cred)
{
	aa_free_task_context(cred->security);
	cred->security = NULL;
}

/*
 * allocate the apparmor part of blank credentials
 */
static int apparmor_cred_alloc_blank(struct cred *cred, gfp_t gfp)
{
	/* freed by apparmor_cred_free */
	struct aa_task_cxt *cxt = aa_alloc_task_context(gfp);
	if (!cxt)
		return -ENOMEM;

	cred->security = cxt;
	return 0;
}

/*
 * prepare new aa_task_cxt for modification by prepare_cred block
 */
static int apparmor_cred_prepare(struct cred *new, const struct cred *old,
				 gfp_t gfp)
{
	/* freed by apparmor_cred_free */
	struct aa_task_cxt *cxt = aa_alloc_task_context(gfp);
	if (!cxt)
		return -ENOMEM;

	aa_dup_task_context(cxt, old->security);
	new->security = cxt;
	return 0;
}

/*
 * transfer the apparmor data to a blank set of creds
 */
static void apparmor_cred_transfer(struct cred *new, const struct cred *old)
{
	const struct aa_task_cxt *old_cxt = old->security;
	struct aa_task_cxt *new_cxt = new->security;

	aa_dup_task_context(new_cxt, old_cxt);
}

static int apparmor_ptrace_access_check(struct task_struct *child,
					unsigned int mode)
{
	int error = cap_ptrace_access_check(child, mode);
	if (error)
		return error;

	return aa_ptrace(current, child, mode);
}

static int apparmor_ptrace_traceme(struct task_struct *parent)
{
	int error = cap_ptrace_traceme(parent);
	if (error)
		return error;

	return aa_ptrace(parent, current, PTRACE_MODE_ATTACH);
}

/* Derived from security/commoncap.c:cap_capget */
static int apparmor_capget(struct task_struct *target, kernel_cap_t *effective,
			   kernel_cap_t *inheritable, kernel_cap_t *permitted)
{
	struct aa_profile *profile;
	const struct cred *cred;

	rcu_read_lock();
	cred = __task_cred(target);
	profile = aa_cred_profile(cred);

	*effective = cred->cap_effective;
	*inheritable = cred->cap_inheritable;
	*permitted = cred->cap_permitted;

	if (!unconfined(profile) && !COMPLAIN_MODE(profile)) {
		*effective = cap_intersect(*effective, profile->caps.allow);
		*permitted = cap_intersect(*permitted, profile->caps.allow);
	}
	rcu_read_unlock();

	return 0;
}

static int apparmor_capable(const struct cred *cred, struct user_namespace *ns,
			    int cap, int audit)
{
	struct aa_profile *profile;
	/* cap_capable returns 0 on success, else -EPERM */
	int error = cap_capable(cred, ns, cap, audit);
	if (!error) {
		profile = aa_cred_profile(cred);
		if (!unconfined(profile))
			error = aa_capable(current, profile, cap, audit);
	}
	return error;
}

/**
 * common_perm - basic common permission check wrapper fn for paths
 * @op: operation being checked
 * @path: path to check permission of  (NOT NULL)
 * @mask: requested permissions mask
 * @cond: conditional info for the permission request  (NOT NULL)
 *
 * Returns: %0 else error code if error or permission denied
 */
static int common_perm(int op, struct path *path, u32 mask,
		       struct path_cond *cond)
{
	struct aa_profile *profile;
	int error = 0;

	profile = __aa_current_profile();
	if (!unconfined(profile))
		error = aa_path_perm(op, profile, path, 0, mask, cond);

	return error;
}

/**
 * common_perm_dir_dentry - common permission wrapper when path is dir, dentry
 * @op: operation being checked
 * @dir: directory of the dentry  (NOT NULL)
 * @dentry: dentry to check  (NOT NULL)
 * @mask: requested permissions mask
 * @cond: conditional info for the permission request  (NOT NULL)
 *
 * Returns: %0 else error code if error or permission denied
 */
static int common_perm_dir_dentry(int op,</