policy.h

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/*
 * AppArmor security module
 *
 * This file contains AppArmor policy definitions.
 *
 * 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.
 */

#ifndef __AA_POLICY_H
#define __AA_POLICY_H

#include <linux/capability.h>
#include <linux/cred.h>
#include <linux/kref.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/socket.h>

#include "apparmor.h"
#include "audit.h"
#include "capability.h"
#include "domain.h"
#include "file.h"
#include "resource.h"

extern const char *const profile_mode_names[];
#define APPARMOR_NAMES_MAX_INDEX 3

#define COMPLAIN_MODE(_profile) \
    ((aa_g_profile_mode == APPARMOR_COMPLAIN) || \
     ((_profile)->mode == APPARMOR_COMPLAIN))

#define KILL_MODE(_profile) \
    ((aa_g_profile_mode == APPARMOR_KILL) || \
     ((_profile)->mode == APPARMOR_KILL))

#define PROFILE_IS_HAT(_profile) ((_profile)->flags & PFLAG_HAT)

/*
 * FIXME: currently need a clean way to replace and remove profiles as a
 * set.  It should be done at the namespace level.
 * Either, with a set of profiles loaded at the namespace level or via
 * a mark and remove marked interface.
 */
enum profile_mode {
    APPARMOR_ENFORCE,   /* enforce access rules */
    APPARMOR_COMPLAIN,  /* allow and log access violations */
    APPARMOR_KILL,      /* kill task on access violation */
};

enum profile_flags {
    PFLAG_HAT = 1,          /* profile is a hat */
    PFLAG_UNCONFINED = 2,       /* profile is an unconfined profile */
    PFLAG_NULL = 4,         /* profile is null learning profile */
    PFLAG_IX_ON_NAME_ERROR = 8, /* fallback to ix on name lookup fail */
    PFLAG_IMMUTABLE = 0x10,     /* don't allow changes/replacement */
    PFLAG_USER_DEFINED = 0x20,  /* user based profile - lower privs */
    PFLAG_NO_LIST_REF = 0x40,   /* list doesn't keep profile ref */
    PFLAG_OLD_NULL_TRANS = 0x100,   /* use // as the null transition */

    /* These flags must correspond with PATH_flags */
    PFLAG_MEDIATE_DELETED = 0x10000, /* mediate instead delegate deleted */
};

struct aa_profile;

/* struct aa_policy - common part of both namespaces and profiles
 * @name: name of the object
 * @hname - The hierarchical name
 * @count: reference count of the obj
 * @list: list policy object is on
 * @profiles: head of the profiles list contained in the object
 */
struct aa_policy {
    char *name;
    char *hname;
    struct kref count;
    struct list_head list;
    struct list_head profiles;
};

/* struct aa_ns_acct - accounting of profiles in namespace
 * @max_size: maximum space allowed for all profiles in namespace
 * @max_count: maximum number of profiles that can be in this namespace
 * @size: current size of profiles
 * @count: current count of profiles (includes null profiles)
 */
struct aa_ns_acct {
    int max_size;
    int max_count;
    int size;
    int count;
};

/* struct aa_namespace - namespace for a set of profiles
 * @base: common policy
 * @parent: parent of namespace
 * @lock: lock for modifying the object
 * @acct: accounting for the namespace
 * @unconfined: special unconfined profile for the namespace
 * @sub_ns: list of namespaces under the current namespace.
 *
 * An aa_namespace defines the set profiles that are searched to determine
 * which profile to attach to a task.  Profiles can not be shared between
 * aa_namespaces and profile names within a namespace are guaranteed to be
 * unique.  When profiles in separate namespaces have the same name they
 * are NOT considered to be equivalent.
 *
 * Namespaces are hierarchical and only namespaces and profiles below the
 * current namespace are visible.
 *
 * Namespace names must be unique and can not contain the characters :/\0
 *
 * FIXME TODO: add vserver support of namespaces (can it all be done in
 *             userspace?)
 */
struct aa_namespace {
    struct aa_policy base;
    struct aa_namespace *parent;
    rwlock_t lock;
    struct aa_ns_acct acct;
    struct aa_profile *unconfined;
    struct list_head sub_ns;
};

/* struct aa_policydb - match engine for a policy
 * dfa: dfa pattern match
 * start: set of start states for the different classes of data
 */
struct aa_policydb {
    /* Generic policy DFA specific rule types will be subsections of it */
    struct aa_dfa *dfa;
    unsigned int start[AA_CLASS_LAST + 1];

};

/* struct aa_profile - basic confinement data
 * @base - base components of the profile (name, refcount, lists, lock ...)
 * @parent: parent of profile
 * @ns: namespace the profile is in
 * @replacedby: is set to the profile that replaced this profile
 * @rename: optional profile name that this profile renamed
 * @xmatch: optional extended matching for unconfined executables names
 * @xmatch_len: xmatch prefix len, used to determine xmatch priority
 * @sid: the unique security id number of this profile
 * @audit: the auditing mode of the profile
 * @mode: the enforcement mode of the profile
 * @flags: flags controlling profile behavior
 * @path_flags: flags controlling path generation behavior
 * @size: the memory consumed by this profiles rules
 * @policy: general match rules governing policy
 * @file: The set of rules governing basic file access and domain transitions
 * @caps: capabilities for the profile
 * @rlimits: rlimits for the profile
 *
 * The AppArmor profile contains the basic confinement data.  Each profile
 * has a name, and exists in a namespace.  The @name and @exec_match are
 * used to determine profile attachment against unconfined tasks.  All other
 * attachments are determined by profile X transition rules.
 *
 * The @replacedby field is write protected by the profile lock.  Reads
 * are assumed to be atomic, and are done without locking.
 *
 * Profiles have a hierarchy where hats and children profiles keep
 * a reference to their parent.
 *
 * Profile names can not begin with a : and can not contain the \0
 * character.  If a profile name begins with / it will be considered when
 * determining profile attachment on "unconfined" tasks.
 */
struct aa_profile {
    struct aa_policy base;
    struct aa_profile *parent;

    struct aa_namespace *ns;
    struct aa_profile *replacedby;
    const char *rename;

    struct aa_dfa *xmatch;
    int xmatch_len;
    u32 sid;
    enum audit_mode audit;
    enum profile_mode mode;
    u32 flags;
    u32 path_flags;
    int size;

    struct aa_policydb policy;
    struct aa_file_rules file;
    struct aa_caps caps;
    struct aa_rlimit rlimits;
};

extern struct aa_namespace *root_ns;
extern enum profile_mode aa_g_profile_mode;

void aa_add_profile(struct aa_policy *common, struct aa_profile *profile);

bool aa_ns_visible(struct aa_namespace *curr, struct aa_namespace *view);
const char *aa_ns_name(struct aa_namespace *parent, struct aa_namespace *child);
int aa_alloc_root_ns(void);
void aa_free_root_ns(void);
void aa_free_namespace_kref(struct kref *kref);

struct aa_namespace *aa_find_namespace(struct aa_namespace *root,
                       const char *name);

static inline struct aa_policy *aa_get_common(struct aa_policy *c)
{
    if (c)
        kref_get(&c->count);

    return c;
}

static inline struct aa_namespace *aa_get_namespace(struct aa_namespace *ns)
{
    if (ns)
        kref_get(&(ns->base.count));

    return ns;
}

static inline void aa_put_namespace(struct aa_namespace *ns)
{
    if (ns)
        kref_put(&ns->base.count, aa_free_namespace_kref);
}

struct aa_profile *aa_alloc_profile(const char *name);
struct aa_profile *aa_new_null_profile(struct aa_profile *parent, int hat);
void aa_free_profile_kref(struct kref *kref);
struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name);
struct aa_profile *aa_lookup_profile(struct aa_namespace *ns, const char *name);
struct aa_profile *aa_match_profile(struct aa_namespace *ns, const char *name);

ssize_t aa_replace_profiles(void *udata, size_t size, bool noreplace);
ssize_t aa_remove_profiles(char *name, size_t size);

#define PROF_ADD 1
#define PROF_REPLACE 0

#define unconfined(X) ((X)->flags & PFLAG_UNCONFINED)

static inline struct aa_profile *aa_newest_version(struct aa_profile *profile)
{
    while (profile->replacedby)
        profile = profile->replacedby;

    return profile;
}

static inline struct aa_profile *aa_get_profile(struct aa_profile *p)
{
    if (p)
        kref_get(&(p->base.count));

    return p;
}

static inline void aa_put_profile(struct aa_profile *p)
{
    if (p)
        kref_put(&p->base.count, aa_free_profile_kref);
}

static inline int AUDIT_MODE(struct aa_profile *profile)
{
    if (aa_g_audit != AUDIT_NORMAL)
        return aa_g_audit;

    return profile->audit;
}

bool aa_may_manage_policy(int op);

#endif /* __AA_POLICY_H */