apparmor: add the base fns() for domain labels

/*

 * AppArmor security module

 *

 * This file contains AppArmor label definitions

 *

 * Copyright 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.

 */

#ifndef __AA_LABEL_H

#define __AA_LABEL_H

#include <linux/atomic.h>

#include <linux/audit.h>

#include <linux/rbtree.h>

#include <linux/rcupdate.h>

#include "apparmor.h"

#include "lib.h"

struct aa_ns;

#define LOCAL_VEC_ENTRIES 8

#define DEFINE_VEC(T, V)						\

	struct aa_ ## T *(_ ## V ## _localtmp)[LOCAL_VEC_ENTRIES];	\

	struct aa_ ## T **(V)

#define vec_setup(T, V, N, GFP)						\

({									\

	if ((N) <= LOCAL_VEC_ENTRIES) {					\

		typeof(N) i;						\

		(V) = (_ ## V ## _localtmp);				\

		for (i = 0; i < (N); i++)				\

			(V)[i] = NULL;					\

	} else								\

		(V) = kzalloc(sizeof(struct aa_ ## T *) * (N), (GFP));	\

	(V) ? 0 : -ENOMEM;						\

})

#define vec_cleanup(T, V, N)						\

do {									\

	int i;								\

	for (i = 0; i < (N); i++) {					\

		if (!IS_ERR_OR_NULL((V)[i]))				\

			aa_put_ ## T((V)[i]);				\

	}								\

	if ((V) != _ ## V ## _localtmp)					\

		kfree(V);						\

} while (0)

#define vec_last(VEC, SIZE) ((VEC)[(SIZE) - 1])

#define vec_ns(VEC, SIZE) (vec_last((VEC), (SIZE))->ns)

#define vec_labelset(VEC, SIZE) (&vec_ns((VEC), (SIZE))->labels)

#define cleanup_domain_vec(V, L) cleanup_label_vec((V), (L)->size)

struct aa_profile;

#define VEC_FLAG_TERMINATE 1

int aa_vec_unique(struct aa_profile **vec, int n, int flags);

struct aa_label *aa_vec_find_or_create_label(struct aa_profile **vec, int len,

					     gfp_t gfp);

#define aa_sort_and_merge_vec(N, V) \

	aa_sort_and_merge_profiles((N), (struct aa_profile **)(V))

/* struct aa_labelset - set of labels for a namespace

 *

 * Labels are reference counted; aa_labelset does not contribute to label

 * reference counts. Once a label's last refcount is put it is removed from

 * the set.

 */

struct aa_labelset {

	rwlock_t lock;

	struct rb_root root;

};

#define __labelset_for_each(LS, N) \

	for ((N) = rb_first(&(LS)->root); (N); (N) = rb_next(N))

void aa_labelset_destroy(struct aa_labelset *ls);

void aa_labelset_init(struct aa_labelset *ls);

enum label_flags {

	FLAG_HAT = 1,			/* profile is a hat */

	FLAG_UNCONFINED = 2,		/* label unconfined only if all */

	FLAG_NULL = 4,			/* profile is null learning profile */

	FLAG_IX_ON_NAME_ERROR = 8,	/* fallback to ix on name lookup fail */

	FLAG_IMMUTIBLE = 0x10,		/* don't allow changes/replacement */

	FLAG_USER_DEFINED = 0x20,	/* user based profile - lower privs */

	FLAG_NO_LIST_REF = 0x40,	/* list doesn't keep profile ref */

	FLAG_NS_COUNT = 0x80,		/* carries NS ref count */

	FLAG_IN_TREE = 0x100,		/* label is in tree */

	FLAG_PROFILE = 0x200,		/* label is a profile */

	FLAG_EXPLICIT = 0x400,		/* explicit static label */

	FLAG_STALE = 0x800,		/* replaced/removed */

	FLAG_RENAMED = 0x1000,		/* label has renaming in it */

	FLAG_REVOKED = 0x2000,		/* label has revocation in it */

	/* These flags must correspond with PATH_flags */

	/* TODO: add new path flags */

};

struct aa_label;

struct aa_proxy {

	struct kref count;

	struct aa_label __rcu *label;

};

struct label_it {

	int i, j;

};

/* struct aa_label - lazy labeling struct

 * @count: ref count of active users

 * @node: rbtree position

 * @rcu: rcu callback struct

 * @proxy: is set to the label that replaced this label

 * @hname: text representation of the label (MAYBE_NULL)

 * @flags: stale and other flags - values may change under label set lock

 * @secid: secid that references this label

 * @size: number of entries in @ent[]

 * @ent: set of profiles for label, actual size determined by @size

 */

struct aa_label {

	struct kref count;

	struct rb_node node;

	struct rcu_head rcu;

	struct aa_proxy *proxy;

	__counted char *hname;

	long flags;

	u32 secid;

	int size;

	struct aa_profile *vec[];

};

#define last_error(E, FN)				\

do {							\

	int __subE = (FN);				\

	if (__subE)					\

		(E) = __subE;				\

} while (0)

#define label_isprofile(X) ((X)->flags & FLAG_PROFILE)

#define label_unconfined(X) ((X)->flags & FLAG_UNCONFINED)

#define unconfined(X) label_unconfined(X)

#define label_is_stale(X) ((X)->flags & FLAG_STALE)

#define __label_make_stale(X) ((X)->flags |= FLAG_STALE)

#define labels_ns(X) (vec_ns(&((X)->vec[0]), (X)->size))

#define labels_set(X) (&labels_ns(X)->labels)

#define labels_profile(X) ((X)->vec[(X)->size - 1])

int aa_label_next_confined(struct aa_label *l, int i);

/* for each profile in a label */

#define label_for_each(I, L, P)						\

	for ((I).i = 0; ((P) = (L)->vec[(I).i]); ++((I).i))

/* assumes break/goto ended label_for_each */

#define label_for_each_cont(I, L, P)					\

	for (++((I).i); ((P) = (L)->vec[(I).i]); ++((I).i))

#define next_comb(I, L1, L2)						\

do {									\

	(I).j++;							\

	if ((I).j >= (L2)->size) {					\

		(I).i++;						\

		(I).j = 0;						\

	}								\

} while (0)

/* for each combination of P1 in L1, and P2 in L2 */

#define label_for_each_comb(I, L1, L2, P1, P2)				\

for ((I).i = (I).j = 0;							\

	((P1) = (L1)->vec[(I).i]) && ((P2) = (L2)->vec[(I).j]);		\

	(I) = next_comb(I, L1, L2))

#define fn_for_each_comb(L1, L2, P1, P2, FN)				\

({									\

	struct label_it i;						\

	int __E = 0;							\

	label_for_each_comb(i, (L1), (L2), (P1), (P2)) {		\

		last_error(__E, (FN));					\

	}								\

	__E;								\

})

/* for each profile that is enforcing confinement in a label */

#define label_for_each_confined(I, L, P)				\

	for ((I).i = aa_label_next_confined((L), 0);			\

	     ((P) = (L)->vec[(I).i]);					\

	     (I).i = aa_label_next_confined((L), (I).i + 1))

#define label_for_each_in_merge(I, A, B, P)				\

	for ((I).i = (I).j = 0;						\

	     ((P) = aa_label_next_in_merge(&(I), (A), (B)));		\

	     )

#define label_for_each_not_in_set(I, SET, SUB, P)			\

	for ((I).i = (I).j = 0;						\

	     ((P) = __aa_label_next_not_in_set(&(I), (SET), (SUB)));	\

	     )

#define next_in_ns(i, NS, L)						\

({									\

	typeof(i) ___i = (i);						\

	while ((L)->vec[___i] && (L)->vec[___i]->ns != (NS))		\

		(___i)++;						\

	(___i);								\

})

#define label_for_each_in_ns(I, NS, L, P)				\

	for ((I).i = next_in_ns(0, (NS), (L));				\

	     ((P) = (L)->vec[(I).i]);					\

	     (I).i = next_in_ns((I).i + 1, (NS), (L)))

#define fn_for_each_in_ns(L, P, FN)					\

({									\

	struct label_it __i;						\

	struct aa_ns *__ns = labels_ns(L);				\

	int __E = 0;							\

	label_for_each_in_ns(__i, __ns, (L), (P)) {			\

		last_error(__E, (FN));					\

	}								\

	__E;								\

})

#define fn_for_each_XXX(L, P, FN, ...)					\

({									\

	struct label_it i;						\

	int __E = 0;							\

	label_for_each ## __VA_ARGS__(i, (L), (P)) {			\

		last_error(__E, (FN));					\

	}								\

	__E;								\

})

#define fn_for_each(L, P, FN) fn_for_each_XXX(L, P, FN)

#define fn_for_each_confined(L, P, FN) fn_for_each_XXX(L, P, FN, _confined)

#define fn_for_each2_XXX(L1, L2, P, FN, ...)				\

({									\

	struct label_it i;						\

	int __E = 0;							\

	label_for_each ## __VA_ARGS__(i, (L1), (L2), (P)) {		\

		last_error(__E, (FN));					\

	}								\

	__E;								\

})

#define fn_for_each_in_merge(L1, L2, P, FN)				\

	fn_for_each2_XXX((L1), (L2), P, FN, _in_merge)

#define fn_for_each_not_in_set(L1, L2, P, FN)				\

	fn_for_each2_XXX((L1), (L2), P, FN, _not_in_set)

#define LABEL_MEDIATES(L, C)						\

({									\

	struct aa_profile *profile;					\

	struct label_it i;						\

	int ret = 0;							\

	label_for_each(i, (L), profile) {				\

		if (PROFILE_MEDIATES(profile, (C))) {			\

			ret = 1;					\

			break;						\

		}							\

	}								\

	ret;								\

})

void aa_labelset_destroy(struct aa_labelset *ls);

void aa_labelset_init(struct aa_labelset *ls);

void __aa_labelset_update_subtree(struct aa_ns *ns);

void aa_label_free(struct aa_label *label);

void aa_label_kref(struct kref *kref);

bool aa_label_init(struct aa_label *label, int size);

struct aa_label *aa_label_alloc(int size, struct aa_proxy *proxy, gfp_t gfp);

bool aa_label_is_subset(struct aa_label *set, struct aa_label *sub);

struct aa_profile *__aa_label_next_not_in_set(struct label_it *I,

					     struct aa_label *set,

					     struct aa_label *sub);

bool aa_label_remove(struct aa_label *label);

struct aa_label *aa_label_insert(struct aa_labelset *ls, struct aa_label *l);

bool aa_label_replace(struct aa_label *old, struct aa_label *new);

bool aa_label_make_newest(struct aa_labelset *ls, struct aa_label *old,

			  struct aa_label *new);

struct aa_label *aa_label_find(struct aa_label *l);

struct aa_profile *aa_label_next_in_merge(struct label_it *I,

					  struct aa_label *a,

					  struct aa_label *b);

struct aa_label *aa_label_find_merge(struct aa_label *a, struct aa_label *b);

struct aa_label *aa_label_merge(struct aa_label *a, struct aa_label *b,

				gfp_t gfp);

bool aa_update_label_name(struct aa_ns *ns, struct aa_label *label, gfp_t gfp);

#define FLAGS_NONE 0

#define FLAG_SHOW_MODE 1

#define FLAG_VIEW_SUBNS 2

#define FLAG_HIDDEN_UNCONFINED 4

int aa_label_snxprint(char *str, size_t size, struct aa_ns *view,

		      struct aa_label *label, int flags);

int aa_label_asxprint(char **strp, struct aa_ns *ns, struct aa_label *label,

		      int flags, gfp_t gfp);

int aa_label_acntsxprint(char __counted **strp, struct aa_ns *ns,

			 struct aa_label *label, int flags, gfp_t gfp);

void aa_label_xaudit(struct audit_buffer *ab, struct aa_ns *ns,

		     struct aa_label *label, int flags, gfp_t gfp);

void aa_label_seq_xprint(struct seq_file *f, struct aa_ns *ns,

			 struct aa_label *label, int flags, gfp_t gfp);

void aa_label_xprintk(struct aa_ns *ns, struct aa_label *label, int flags,

		      gfp_t gfp);

void aa_label_audit(struct audit_buffer *ab, struct aa_label *label, gfp_t gfp);

void aa_label_seq_print(struct seq_file *f, struct aa_label *label, gfp_t gfp);

void aa_label_printk(struct aa_label *label, gfp_t gfp);

struct aa_label *aa_label_parse(struct aa_label *base, const char *str,

				gfp_t gfp, bool create, bool force_stack);

struct aa_perms;

int aa_label_match(struct aa_profile *profile, struct aa_label *label,

		   unsigned int state, bool subns, u32 request,

		   struct aa_perms *perms);

/**

 * __aa_get_label - get a reference count to uncounted label reference

 * @l: reference to get a count on

 *

 * Returns: pointer to reference OR NULL if race is lost and reference is

 *          being repeated.

 * Requires: lock held, and the return code MUST be checked

 */

static inline struct aa_label *__aa_get_label(struct aa_label *l)

{

	if (l && kref_get_unless_zero(&l->count))

		return l;

	return NULL;

}

static inline struct aa_label *aa_get_label(struct aa_label *l)

{

	if (l)

		kref_get(&(l->count));

	return l;

}

/**

 * aa_get_label_rcu - increment refcount on a label that can be replaced

 * @l: pointer to label that can be replaced (NOT NULL)

 *

 * Returns: pointer to a refcounted label.

 *     else NULL if no label

 */

static inline struct aa_label *aa_get_label_rcu(struct aa_label __rcu **l)

{

	struct aa_label *c;

	rcu_read_lock();

	do {

		c = rcu_dereference(*l);

	} while (c && !kref_get_unless_zero(&c->count));

	rcu_read_unlock();

	return c;

}

/**

 * aa_get_newest_label - find the newest version of @l

 * @l: the label to check for newer versions of

 *

 * Returns: refcounted newest version of @l taking into account

 *          replacement, renames and removals

 *          return @l.

 */

static inline struct aa_label *aa_get_newest_label(struct aa_label *l)

{

	if (!l)

		return NULL;

	if (label_is_stale(l)) {

		struct aa_label *tmp;

		AA_BUG(!l->proxy);

		AA_BUG(!l->proxy->label);

		/* BUG: only way this can happen is @l ref count and its

		 * replacement count have gone to 0 and are on their way

		 * to destruction. ie. we have a refcounting error

		 */

		tmp = aa_get_label_rcu(&l->proxy->label);

		AA_BUG(!tmp);

		return tmp;

	}

	return aa_get_label(l);

}

static inline void aa_put_label(struct aa_label *l)

{

	if (l)

		kref_put(&l->count, aa_label_kref);

}

struct aa_proxy *aa_alloc_proxy(struct aa_label *l, gfp_t gfp);

void aa_proxy_kref(struct kref *kref);

static inline struct aa_proxy *aa_get_proxy(struct aa_proxy *proxy)

{

	if (proxy)

		kref_get(&(proxy->count));

	return proxy;

}

static inline void aa_put_proxy(struct aa_proxy *proxy)

{

	if (proxy)

		kref_put(&proxy->count, aa_proxy_kref);

}

void __aa_proxy_redirect(struct aa_label *orig, struct aa_label *new);

#endif /* __AA_LABEL_H */