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Commit 2f3e82d6 authored by Stephen Smalley's avatar Stephen Smalley Committed by James Morris
Browse files

selinux: convert range transition list to a hashtab 

Per https://bugzilla.redhat.com/show_bug.cgi?id=548145


there are sufficient range transition rules in modern (Fedora) policy to
make mls_compute_sid a significant factor on the shmem file setup path
due to the length of the range_tr list.  Replace the simple range_tr
list with a hashtab inside the security server to help mitigate this
problem.

Signed-off-by: default avatarStephen D. Smalley <sds@tycho.nsa.gov>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 2457552d

security/selinux/ss/mls.c

+8 −10
Original line number Diff line number Diff line
@@ -513,7 +513,8 @@ int mls_compute_sid(struct context *scontext, 
		    u32 specified,

		    struct context *newcontext)

{

	struct range_trans *rtr;

	struct range_trans rtr;

	struct mls_range *r;



	if (!selinux_mls_enabled)

		return 0;
@@ -521,15 +522,12 @@ int mls_compute_sid(struct context *scontext, 
	switch (specified) {

	case AVTAB_TRANSITION:

		/* Look for a range transition rule. */

		for (rtr = policydb.range_tr; rtr; rtr = rtr->next) {

			if (rtr->source_type == scontext->type &&

			    rtr->target_type == tcontext->type &&

			    rtr->target_class == tclass) {

				/* Set the range from the rule */

				return mls_range_set(newcontext,

						     &rtr->target_range);

			}

		}

		rtr.source_type = scontext->type;

		rtr.target_type = tcontext->type;

		rtr.target_class = tclass;

		r = hashtab_search(policydb.range_tr, &rtr);

		if (r)

			return mls_range_set(newcontext, r);

		/* Fallthrough */

	case AVTAB_CHANGE:

		if (tclass == policydb.process_class)

security/selinux/ss/policydb.c

+76 −27
Original line number Diff line number Diff line
@@ -177,6 +177,21 @@ static int roles_init(struct policydb *p) 
	goto out;

}



static u32 rangetr_hash(struct hashtab *h, const void *k)

{

	const struct range_trans *key = k;

	return (key->source_type + (key->target_type << 3) +

		(key->target_class << 5)) & (h->size - 1);

}



static int rangetr_cmp(struct hashtab *h, const void *k1, const void *k2)

{

	const struct range_trans *key1 = k1, *key2 = k2;

	return (key1->source_type != key2->source_type ||

		key1->target_type != key2->target_type ||

		key1->target_class != key2->target_class);

}



/*

 * Initialize a policy database structure.

 */
@@ -204,6 +219,10 @@ static int policydb_init(struct policydb *p) 
	if (rc)

		goto out_free_symtab;



	p->range_tr = hashtab_create(rangetr_hash, rangetr_cmp, 256);

	if (!p->range_tr)

		goto out_free_symtab;



	ebitmap_init(&p->policycaps);

	ebitmap_init(&p->permissive_map);
@@ -408,6 +427,20 @@ static void symtab_hash_eval(struct symtab *s) 
		       info.slots_used, h->size, info.max_chain_len);

	}

}



static void rangetr_hash_eval(struct hashtab *h)

{

	struct hashtab_info info;



	hashtab_stat(h, &info);

	printk(KERN_DEBUG "SELinux: rangetr:  %d entries and %d/%d buckets used, "

	       "longest chain length %d\n", h->nel,

	       info.slots_used, h->size, info.max_chain_len);

}

#else

static inline void rangetr_hash_eval(struct hashtab *h)

{

}

#endif



/*
@@ -612,6 +645,17 @@ static int (*destroy_f[SYM_NUM]) (void *key, void *datum, void *datap) = 
	cat_destroy,

};



static int range_tr_destroy(void *key, void *datum, void *p)

{

	struct mls_range *rt = datum;

	kfree(key);

	ebitmap_destroy(&rt->level[0].cat);

	ebitmap_destroy(&rt->level[1].cat);

	kfree(datum);

	cond_resched();

	return 0;

}



static void ocontext_destroy(struct ocontext *c, int i)

{

	context_destroy(&c->context[0]);
@@ -632,7 +676,6 @@ void policydb_destroy(struct policydb *p) 
	int i;

	struct role_allow *ra, *lra = NULL;

	struct role_trans *tr, *ltr = NULL;

	struct range_trans *rt, *lrt = NULL;



	for (i = 0; i < SYM_NUM; i++) {

		cond_resched();
@@ -693,20 +736,8 @@ void policydb_destroy(struct policydb *p) 
	}

	kfree(lra);



	for (rt = p->range_tr; rt; rt = rt->next) {

		cond_resched();

		if (lrt) {

			ebitmap_destroy(&lrt->target_range.level[0].cat);

			ebitmap_destroy(&lrt->target_range.level[1].cat);

			kfree(lrt);

		}

		lrt = rt;

	}

	if (lrt) {

		ebitmap_destroy(&lrt->target_range.level[0].cat);

		ebitmap_destroy(&lrt->target_range.level[1].cat);

		kfree(lrt);

	}

	hashtab_map(p->range_tr, range_tr_destroy, NULL);

	hashtab_destroy(p->range_tr);



	if (p->type_attr_map) {

		for (i = 0; i < p->p_types.nprim; i++)
@@ -1689,7 +1720,8 @@ int policydb_read(struct policydb *p, void *fp) 
	u32 len, len2, config, nprim, nel, nel2;

	char *policydb_str;

	struct policydb_compat_info *info;

	struct range_trans *rt, *lrt;

	struct range_trans *rt;

	struct mls_range *r;



	config = 0;
@@ -2122,44 +2154,61 @@ int policydb_read(struct policydb *p, void *fp) 
		if (rc < 0)

			goto bad;

		nel = le32_to_cpu(buf[0]);

		lrt = NULL;

		for (i = 0; i < nel; i++) {

			rt = kzalloc(sizeof(*rt), GFP_KERNEL);

			if (!rt) {

				rc = -ENOMEM;

				goto bad;

			}

			if (lrt)

				lrt->next = rt;

			else

				p->range_tr = rt;

			rc = next_entry(buf, fp, (sizeof(u32) * 2));

			if (rc < 0)

			if (rc < 0) {

				kfree(rt);

				goto bad;

			}

			rt->source_type = le32_to_cpu(buf[0]);

			rt->target_type = le32_to_cpu(buf[1]);

			if (new_rangetr) {

				rc = next_entry(buf, fp, sizeof(u32));

				if (rc < 0)

				if (rc < 0) {

					kfree(rt);

					goto bad;

				}

				rt->target_class = le32_to_cpu(buf[0]);

			} else

				rt->target_class = p->process_class;

			if (!policydb_type_isvalid(p, rt->source_type) ||

			    !policydb_type_isvalid(p, rt->target_type) ||

			    !policydb_class_isvalid(p, rt->target_class)) {

				kfree(rt);

				rc = -EINVAL;

				goto bad;

			}

			rc = mls_read_range_helper(&rt->target_range, fp);

			if (rc)

			r = kzalloc(sizeof(*r), GFP_KERNEL);

			if (!r) {

				kfree(rt);

				rc = -ENOMEM;

				goto bad;

			if (!mls_range_isvalid(p, &rt->target_range)) {

			}

			rc = mls_read_range_helper(r, fp);

			if (rc) {

				kfree(rt);

				kfree(r);

				goto bad;

			}

			if (!mls_range_isvalid(p, r)) {

				printk(KERN_WARNING "SELinux:  rangetrans:  invalid range\n");

				kfree(rt);

				kfree(r);

				goto bad;

			}

			rc = hashtab_insert(p->range_tr, rt, r);

			if (rc) {

				kfree(rt);

				kfree(r);

				goto bad;

			}

			lrt = rt;

		}

		rangetr_hash_eval(p->range_tr);

	}



	p->type_attr_map = kmalloc(p->p_types.nprim*sizeof(struct ebitmap), GFP_KERNEL);

security/selinux/ss/policydb.h

+2 −4
Original line number Diff line number Diff line
@@ -113,8 +113,6 @@ struct range_trans { 
	u32 source_type;

	u32 target_type;

	u32 target_class;

	struct mls_range target_range;

	struct range_trans *next;

};



/* Boolean data type */
@@ -240,8 +238,8 @@ struct policydb { 
	   fixed labeling behavior. */

	struct genfs *genfs;



	/* range transitions */

	struct range_trans *range_tr;

	/* range transitions table (range_trans_key -> mls_range) */

	struct hashtab *range_tr;



	/* type -> attribute reverse mapping */

	struct ebitmap *type_attr_map;