security/selinux/ss/sidtab.c - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Implementation of the SID table type.
  *
  * Original author: Stephen Smalley, <sds@tycho.nsa.gov>
  * Author: Ondrej Mosnacek, <omosnacek@gmail.com>
  *
  * Copyright (C) 2018 Red Hat, Inc.
  */
 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/spinlock.h>
 #include <asm/barrier.h>
 #include "flask.h"
 #include "security.h"
 #include "sidtab.h"

 #define index_to_sid(index) (index + SECINITSID_NUM + 1)
 #define sid_to_index(sid) (sid - (SECINITSID_NUM + 1))

 int sidtab_init(struct sidtab *s)
 {
 	u32 i;

 	memset(s->roots, 0, sizeof(s->roots));

 	for (i = 0; i < SECINITSID_NUM; i++)
 		s->isids[i].set = 0;

 	s->count = 0;
 	s->convert = NULL;
 	hash_init(s->context_to_sid);

 	spin_lock_init(&s->lock);
 	return 0;
 }

 static u32 context_to_sid(struct sidtab *s, struct context *context)
 {
 	struct sidtab_entry_leaf *entry;
 	u32 sid = 0;

 	rcu_read_lock();
 	hash_for_each_possible_rcu(s->context_to_sid, entry, list,
 				   context->hash) {
 		if (context_cmp(&entry->context, context)) {
 			sid = entry->sid;
 			break;
 		}
 	}
 	rcu_read_unlock();
 	return sid;
 }

 int sidtab_set_initial(struct sidtab *s, u32 sid, struct context *context)
 {
 	struct sidtab_isid_entry *entry;
 	int rc;

 	if (sid == 0 || sid > SECINITSID_NUM)
 		return -EINVAL;

 	entry = &s->isids[sid - 1];

 	rc = context_cpy(&entry->leaf.context, context);
 	if (rc)
 		return rc;

 	entry->set = 1;

 	/*
 	 * Multiple initial sids may map to the same context. Check that this
 	 * context is not already represented in the context_to_sid hashtable
 	 * to avoid duplicate entries and long linked lists upon hash
 	 * collision.
 	 */
 	if (!context_to_sid(s, context)) {
 		entry->leaf.sid = sid;
 		hash_add(s->context_to_sid, &entry->leaf.list, context->hash);
 	}

 	return 0;
 }

 int sidtab_hash_stats(struct sidtab *sidtab, char *page)
 {
 	int i;
 	int chain_len = 0;
 	int slots_used = 0;
 	int entries = 0;
 	int max_chain_len = 0;
 	int cur_bucket = 0;
 	struct sidtab_entry_leaf *entry;

 	rcu_read_lock();
 	hash_for_each_rcu(sidtab->context_to_sid, i, entry, list) {
 		entries++;
 		if (i == cur_bucket) {
 			chain_len++;
 			if (chain_len == 1)
 				slots_used++;
 		} else {
 			cur_bucket = i;
 			if (chain_len > max_chain_len)
 				max_chain_len = chain_len;
 			chain_len = 0;
 		}
 	}
 	rcu_read_unlock();

 	if (chain_len > max_chain_len)
 		max_chain_len = chain_len;

 	return scnprintf(page, PAGE_SIZE, "entries: %d\nbuckets used: %d/%d\n"
 			 "longest chain: %d\n", entries,
 			 slots_used, SIDTAB_HASH_BUCKETS, max_chain_len);
 }

 static u32 sidtab_level_from_count(u32 count)
 {
 	u32 capacity = SIDTAB_LEAF_ENTRIES;
 	u32 level = 0;

 	while (count > capacity) {
 		capacity <<= SIDTAB_INNER_SHIFT;
 		++level;
 	}
 	return level;
 }

 static int sidtab_alloc_roots(struct sidtab *s, u32 level)
 {
 	u32 l;

 	if (!s->roots[0].ptr_leaf) {
 		s->roots[0].ptr_leaf = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
 					       GFP_ATOMIC);
 		if (!s->roots[0].ptr_leaf)
 			return -ENOMEM;
 	}
 	for (l = 1; l <= level; ++l)
 		if (!s->roots[l].ptr_inner) {
 			s->roots[l].ptr_inner = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
 							GFP_ATOMIC);
 			if (!s->roots[l].ptr_inner)
 				return -ENOMEM;
 			s->roots[l].ptr_inner->entries[0] = s->roots[l - 1];
 		}
 	return 0;
 }

 static struct sidtab_entry_leaf *sidtab_do_lookup(struct sidtab *s, u32 index,
 						  int alloc)
 {
 	union sidtab_entry_inner *entry;
 	u32 level, capacity_shift, leaf_index = index / SIDTAB_LEAF_ENTRIES;

 	/* find the level of the subtree we need */
 	level = sidtab_level_from_count(index + 1);
 	capacity_shift = level * SIDTAB_INNER_SHIFT;

 	/* allocate roots if needed */
 	if (alloc && sidtab_alloc_roots(s, level) != 0)
 		return NULL;

 	/* lookup inside the subtree */
 	entry = &s->roots[level];
 	while (level != 0) {
 		capacity_shift -= SIDTAB_INNER_SHIFT;
 		--level;

 		entry = &entry->ptr_inner->entries[leaf_index >> capacity_shift];
 		leaf_index &= ((u32)1 << capacity_shift) - 1;

 		if (!entry->ptr_inner) {
 			if (alloc)
 				entry->ptr_inner = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
 							   GFP_ATOMIC);
 			if (!entry->ptr_inner)
 				return NULL;
 		}
 	}
 	if (!entry->ptr_leaf) {
 		if (alloc)
 			entry->ptr_leaf = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
 						  GFP_ATOMIC);
 		if (!entry->ptr_leaf)
 			return NULL;
 	}
 	return &entry->ptr_leaf->entries[index % SIDTAB_LEAF_ENTRIES];
 }

 static struct context *sidtab_lookup(struct sidtab *s, u32 index)
 {
 	/* read entries only after reading count */
 	u32 count = smp_load_acquire(&s->count);

 	if (index >= count)
 		return NULL;

 	return &sidtab_do_lookup(s, index, 0)->context;
 }

 static struct context *sidtab_lookup_initial(struct sidtab *s, u32 sid)
 {
 	return s->isids[sid - 1].set ? &s->isids[sid - 1].leaf.context : NULL;
 }

 static struct context *sidtab_search_core(struct sidtab *s, u32 sid, int force)
 {
 	struct context *context;

 	if (sid != 0) {
 		if (sid > SECINITSID_NUM)
 			context = sidtab_lookup(s, sid_to_index(sid));
 		else
 			context = sidtab_lookup_initial(s, sid);
 		if (context && (!context->len || force))
 			return context;
 	}

 	return sidtab_lookup_initial(s, SECINITSID_UNLABELED);
 }

 struct context *sidtab_search(struct sidtab *s, u32 sid)
 {
 	return sidtab_search_core(s, sid, 0);
 }

 struct context *sidtab_search_force(struct sidtab *s, u32 sid)
 {
 	return sidtab_search_core(s, sid, 1);
 }

 int sidtab_context_to_sid(struct sidtab *s, struct context *context,
 			  u32 *sid)
 {
 	unsigned long flags;
 	u32 count;
 	struct sidtab_convert_params *convert;
 	struct sidtab_entry_leaf *dst, *dst_convert;
 	int rc;

 	*sid = context_to_sid(s, context);
 	if (*sid)
 		return 0;

 	/* lock-free search failed: lock, re-search, and insert if not found */
 	spin_lock_irqsave(&s->lock, flags);

 	rc = 0;
 	*sid = context_to_sid(s, context);
 	if (*sid)
 		goto out_unlock;

 	/* read entries only after reading count */
 	count = smp_load_acquire(&s->count);
 	convert = s->convert;

 	/* bail out if we already reached max entries */
 	rc = -EOVERFLOW;
 	if (count >= SIDTAB_MAX)
 		goto out_unlock;

 	/* insert context into new entry */
 	rc = -ENOMEM;
 	dst = sidtab_do_lookup(s, count, 1);
 	if (!dst)
 		goto out_unlock;

 	dst->sid = index_to_sid(count);

 	rc = context_cpy(&dst->context, context);
 	if (rc)
 		goto out_unlock;

 	/*
 	 * if we are building a new sidtab, we need to convert the context
 	 * and insert it there as well
 	 */
 	if (convert) {
 		rc = -ENOMEM;
 		dst_convert = sidtab_do_lookup(convert->target, count, 1);
 		if (!dst_convert) {
 			context_destroy(&dst->context);
 			goto out_unlock;
 		}

 		rc = convert->func(context, &dst_convert->context,
 				   convert->args, GFP_ATOMIC);
 		if (rc) {
 			context_destroy(&dst->context);
 			goto out_unlock;
 		}
 		dst_convert->sid = index_to_sid(count);
 		convert->target->count = count + 1;

 		hash_add_rcu(convert->target->context_to_sid,
 				&dst_convert->list, dst_convert->context.hash);
 	}

 	if (context->len)
 		pr_info("SELinux:  Context %s is not valid (left unmapped).\n",
 			context->str);

 	*sid = index_to_sid(count);

 	/* write entries before updating count */
 	smp_store_release(&s->count, count + 1);
 	hash_add_rcu(s->context_to_sid, &dst->list, dst->context.hash);

 	rc = 0;
 out_unlock:
 	spin_unlock_irqrestore(&s->lock, flags);
 	return rc;
 }

 static void sidtab_convert_hashtable(struct sidtab *s, u32 count)
 {
 	struct sidtab_entry_leaf *entry;
 	u32 i;

 	for (i = 0; i < count; i++) {
 		entry = sidtab_do_lookup(s, i, 0);
 		entry->sid = index_to_sid(i);

 		hash_add_rcu(s->context_to_sid, &entry->list,
 				entry->context.hash);

 	}
 }

 static int sidtab_convert_tree(union sidtab_entry_inner *edst,
 			       union sidtab_entry_inner *esrc,
 			       u32 *pos, u32 count, u32 level,
 			       struct sidtab_convert_params *convert)
 {
 	int rc;
 	u32 i;

 	if (level != 0) {
 		if (!edst->ptr_inner) {
 			edst->ptr_inner = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
 						  GFP_KERNEL);
 			if (!edst->ptr_inner)
 				return -ENOMEM;
 		}
 		i = 0;
 		while (i < SIDTAB_INNER_ENTRIES && *pos < count) {
 			rc = sidtab_convert_tree(&edst->ptr_inner->entries[i],
 						 &esrc->ptr_inner->entries[i],
 						 pos, count, level - 1,
 						 convert);
 			if (rc)
 				return rc;
 			i++;
 		}
 	} else {
 		if (!edst->ptr_leaf) {
 			edst->ptr_leaf = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
 						 GFP_KERNEL);
 			if (!edst->ptr_leaf)
 				return -ENOMEM;
 		}
 		i = 0;
 		while (i < SIDTAB_LEAF_ENTRIES && *pos < count) {
 			rc = convert->func(&esrc->ptr_leaf->entries[i].context,
 					   &edst->ptr_leaf->entries[i].context,
 					   convert->args, GFP_KERNEL);
 			if (rc)
 				return rc;
 			(*pos)++;
 			i++;
 		}
 		cond_resched();
 	}

 	return 0;
 }

 int sidtab_convert(struct sidtab *s, struct sidtab_convert_params *params)
 {
 	unsigned long flags;
 	u32 count, level, pos;
 	int rc;

 	spin_lock_irqsave(&s->lock, flags);

 	/* concurrent policy loads are not allowed */
 	if (s->convert) {
 		spin_unlock_irqrestore(&s->lock, flags);
 		return -EBUSY;
 	}

 	count = s->count;
 	level = sidtab_level_from_count(count);

 	/* allocate last leaf in the new sidtab (to avoid race with
 	 * live convert)
 	 */
 	rc = sidtab_do_lookup(params->target, count - 1, 1) ? 0 : -ENOMEM;
 	if (rc) {
 		spin_unlock_irqrestore(&s->lock, flags);
 		return rc;
 	}

 	/* set count in case no new entries are added during conversion */
 	params->target->count = count;

 	/* enable live convert of new entries */
 	s->convert = params;

 	/* we can safely convert the tree outside the lock */
 	spin_unlock_irqrestore(&s->lock, flags);

 	pr_info("SELinux:  Converting %u SID table entries...\n", count);

 	/* convert all entries not covered by live convert */
 	pos = 0;
 	rc = sidtab_convert_tree(&params->target->roots[level],
 				 &s->roots[level], &pos, count, level, params);
 	if (rc) {
 		/* we need to keep the old table - disable live convert */
 		spin_lock_irqsave(&s->lock, flags);
 		s->convert = NULL;
 		spin_unlock_irqrestore(&s->lock, flags);
 		return rc;
 	}
 	/*
 	 * The hashtable can also be modified in sidtab_context_to_sid()
 	 * so we must re-acquire the lock here.
 	 */
 	spin_lock_irqsave(&s->lock, flags);
 	sidtab_convert_hashtable(params->target, count);
 	spin_unlock_irqrestore(&s->lock, flags);

 	return 0;
 }

 static void sidtab_destroy_tree(union sidtab_entry_inner entry, u32 level)
 {
 	u32 i;

 	if (level != 0) {
 		struct sidtab_node_inner *node = entry.ptr_inner;

 		if (!node)
 			return;

 		for (i = 0; i < SIDTAB_INNER_ENTRIES; i++)
 			sidtab_destroy_tree(node->entries[i], level - 1);
 		kfree(node);
 	} else {
 		struct sidtab_node_leaf *node = entry.ptr_leaf;

 		if (!node)
 			return;

 		for (i = 0; i < SIDTAB_LEAF_ENTRIES; i++)
 			context_destroy(&node->entries[i].context);
 		kfree(node);
 	}
 }

 void sidtab_destroy(struct sidtab *s)
 {
 	u32 i, level;

 	for (i = 0; i < SECINITSID_NUM; i++)
 		if (s->isids[i].set)
 			context_destroy(&s->isids[i].leaf.context);

 	level = SIDTAB_MAX_LEVEL;
 	while (level && !s->roots[level].ptr_inner)
 		--level;

 	sidtab_destroy_tree(s->roots[level], level);
 	/*
 	 * The context_to_sid hashtable's objects are all shared
 	 * with the isids array and context tree, and so don't need
 	 * to be cleaned up here.
 	 */
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Implementation of the SID table type.
	*
	* Original author: Stephen Smalley, <sds@tycho.nsa.gov>
	* Author: Ondrej Mosnacek, <omosnacek@gmail.com>
	*
	* Copyright (C) 2018 Red Hat, Inc.
	*/
	#include <linux/errno.h>
	#include <linux/kernel.h>
	#include <linux/slab.h>
	#include <linux/sched.h>
	#include <linux/spinlock.h>
	#include <asm/barrier.h>
	#include "flask.h"
	#include "security.h"
	#include "sidtab.h"

	#define index_to_sid(index) (index + SECINITSID_NUM + 1)
	#define sid_to_index(sid) (sid - (SECINITSID_NUM + 1))

	int sidtab_init(struct sidtab *s)
	{
	u32 i;

	memset(s->roots, 0, sizeof(s->roots));

	for (i = 0; i < SECINITSID_NUM; i++)
	s->isids[i].set = 0;

	s->count = 0;
	s->convert = NULL;
	hash_init(s->context_to_sid);

	spin_lock_init(&s->lock);
	return 0;
	}

	static u32 context_to_sid(struct sidtab s, struct context context)
	{
	struct sidtab_entry_leaf *entry;
	u32 sid = 0;

	rcu_read_lock();
	hash_for_each_possible_rcu(s->context_to_sid, entry, list,
	context->hash) {
	if (context_cmp(&entry->context, context)) {
	sid = entry->sid;
	break;
	}
	}
	rcu_read_unlock();
	return sid;
	}

	int sidtab_set_initial(struct sidtab s, u32 sid, struct context context)
	{
	struct sidtab_isid_entry *entry;
	int rc;

	if (sid == 0 \|\| sid > SECINITSID_NUM)
	return -EINVAL;

	entry = &s->isids[sid - 1];

	rc = context_cpy(&entry->leaf.context, context);
	if (rc)
	return rc;

	entry->set = 1;

	/*
	* Multiple initial sids may map to the same context. Check that this
	* context is not already represented in the context_to_sid hashtable
	* to avoid duplicate entries and long linked lists upon hash
	* collision.
	*/
	if (!context_to_sid(s, context)) {
	entry->leaf.sid = sid;
	hash_add(s->context_to_sid, &entry->leaf.list, context->hash);
	}

	return 0;
	}

	int sidtab_hash_stats(struct sidtab sidtab, char page)
	{
	int i;
	int chain_len = 0;
	int slots_used = 0;
	int entries = 0;
	int max_chain_len = 0;
	int cur_bucket = 0;
	struct sidtab_entry_leaf *entry;

	rcu_read_lock();
	hash_for_each_rcu(sidtab->context_to_sid, i, entry, list) {
	entries++;
	if (i == cur_bucket) {
	chain_len++;
	if (chain_len == 1)
	slots_used++;
	} else {
	cur_bucket = i;
	if (chain_len > max_chain_len)
	max_chain_len = chain_len;
	chain_len = 0;
	}
	}
	rcu_read_unlock();

	if (chain_len > max_chain_len)
	max_chain_len = chain_len;

	return scnprintf(page, PAGE_SIZE, "entries: %d\nbuckets used: %d/%d\n"
	"longest chain: %d\n", entries,
	slots_used, SIDTAB_HASH_BUCKETS, max_chain_len);
	}

	static u32 sidtab_level_from_count(u32 count)
	{
	u32 capacity = SIDTAB_LEAF_ENTRIES;
	u32 level = 0;

	while (count > capacity) {
	capacity <<= SIDTAB_INNER_SHIFT;
	++level;
	}
	return level;
	}

	static int sidtab_alloc_roots(struct sidtab *s, u32 level)
	{
	u32 l;

	if (!s->roots[0].ptr_leaf) {
	s->roots[0].ptr_leaf = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
	GFP_ATOMIC);
	if (!s->roots[0].ptr_leaf)
	return -ENOMEM;
	}
	for (l = 1; l <= level; ++l)
	if (!s->roots[l].ptr_inner) {
	s->roots[l].ptr_inner = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
	GFP_ATOMIC);
	if (!s->roots[l].ptr_inner)
	return -ENOMEM;
	s->roots[l].ptr_inner->entries[0] = s->roots[l - 1];
	}
	return 0;
	}

	static struct sidtab_entry_leaf sidtab_do_lookup(struct sidtab s, u32 index,
	int alloc)
	{
	union sidtab_entry_inner *entry;
	u32 level, capacity_shift, leaf_index = index / SIDTAB_LEAF_ENTRIES;

	/* find the level of the subtree we need */
	level = sidtab_level_from_count(index + 1);
	capacity_shift = level * SIDTAB_INNER_SHIFT;

	/* allocate roots if needed */
	if (alloc && sidtab_alloc_roots(s, level) != 0)
	return NULL;

	/* lookup inside the subtree */
	entry = &s->roots[level];
	while (level != 0) {
	capacity_shift -= SIDTAB_INNER_SHIFT;
	--level;

	entry = &entry->ptr_inner->entries[leaf_index >> capacity_shift];
	leaf_index &= ((u32)1 << capacity_shift) - 1;

	if (!entry->ptr_inner) {
	if (alloc)
	entry->ptr_inner = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
	GFP_ATOMIC);
	if (!entry->ptr_inner)
	return NULL;
	}
	}
	if (!entry->ptr_leaf) {
	if (alloc)
	entry->ptr_leaf = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
	GFP_ATOMIC);
	if (!entry->ptr_leaf)
	return NULL;
	}
	return &entry->ptr_leaf->entries[index % SIDTAB_LEAF_ENTRIES];
	}

	static struct context sidtab_lookup(struct sidtab s, u32 index)
	{
	/* read entries only after reading count */
	u32 count = smp_load_acquire(&s->count);

	if (index >= count)
	return NULL;

	return &sidtab_do_lookup(s, index, 0)->context;
	}

	static struct context sidtab_lookup_initial(struct sidtab s, u32 sid)
	{
	return s->isids[sid - 1].set ? &s->isids[sid - 1].leaf.context : NULL;
	}

	static struct context sidtab_search_core(struct sidtab s, u32 sid, int force)
	{
	struct context *context;

	if (sid != 0) {
	if (sid > SECINITSID_NUM)
	context = sidtab_lookup(s, sid_to_index(sid));
	else
	context = sidtab_lookup_initial(s, sid);
	if (context && (!context->len \|\| force))
	return context;
	}

	return sidtab_lookup_initial(s, SECINITSID_UNLABELED);
	}

	struct context sidtab_search(struct sidtab s, u32 sid)
	{
	return sidtab_search_core(s, sid, 0);
	}

	struct context sidtab_search_force(struct sidtab s, u32 sid)
	{
	return sidtab_search_core(s, sid, 1);
	}

	int sidtab_context_to_sid(struct sidtab s, struct context context,
	u32 *sid)
	{
	unsigned long flags;
	u32 count;
	struct sidtab_convert_params *convert;
	struct sidtab_entry_leaf dst, dst_convert;
	int rc;

	*sid = context_to_sid(s, context);
	if (*sid)
	return 0;

	/* lock-free search failed: lock, re-search, and insert if not found */
	spin_lock_irqsave(&s->lock, flags);

	rc = 0;
	*sid = context_to_sid(s, context);
	if (*sid)
	goto out_unlock;

	/* read entries only after reading count */
	count = smp_load_acquire(&s->count);
	convert = s->convert;

	/* bail out if we already reached max entries */
	rc = -EOVERFLOW;
	if (count >= SIDTAB_MAX)
	goto out_unlock;

	/* insert context into new entry */
	rc = -ENOMEM;
	dst = sidtab_do_lookup(s, count, 1);
	if (!dst)
	goto out_unlock;

	dst->sid = index_to_sid(count);

	rc = context_cpy(&dst->context, context);
	if (rc)
	goto out_unlock;

	/*
	* if we are building a new sidtab, we need to convert the context
	* and insert it there as well
	*/
	if (convert) {
	rc = -ENOMEM;
	dst_convert = sidtab_do_lookup(convert->target, count, 1);
	if (!dst_convert) {
	context_destroy(&dst->context);
	goto out_unlock;
	}

	rc = convert->func(context, &dst_convert->context,
	convert->args, GFP_ATOMIC);
	if (rc) {
	context_destroy(&dst->context);
	goto out_unlock;
	}
	dst_convert->sid = index_to_sid(count);
	convert->target->count = count + 1;

	hash_add_rcu(convert->target->context_to_sid,
	&dst_convert->list, dst_convert->context.hash);
	}

	if (context->len)
	pr_info("SELinux: Context %s is not valid (left unmapped).\n",
	context->str);

	*sid = index_to_sid(count);

	/* write entries before updating count */
	smp_store_release(&s->count, count + 1);
	hash_add_rcu(s->context_to_sid, &dst->list, dst->context.hash);

	rc = 0;
	out_unlock:
	spin_unlock_irqrestore(&s->lock, flags);
	return rc;
	}

	static void sidtab_convert_hashtable(struct sidtab *s, u32 count)
	{
	struct sidtab_entry_leaf *entry;
	u32 i;

	for (i = 0; i < count; i++) {
	entry = sidtab_do_lookup(s, i, 0);
	entry->sid = index_to_sid(i);

	hash_add_rcu(s->context_to_sid, &entry->list,
	entry->context.hash);

	}
	}

	static int sidtab_convert_tree(union sidtab_entry_inner *edst,
	union sidtab_entry_inner *esrc,
	u32 *pos, u32 count, u32 level,
	struct sidtab_convert_params *convert)
	{
	int rc;
	u32 i;

	if (level != 0) {
	if (!edst->ptr_inner) {
	edst->ptr_inner = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
	GFP_KERNEL);
	if (!edst->ptr_inner)
	return -ENOMEM;
	}
	i = 0;
	while (i < SIDTAB_INNER_ENTRIES && *pos < count) {
	rc = sidtab_convert_tree(&edst->ptr_inner->entries[i],
	&esrc->ptr_inner->entries[i],
	pos, count, level - 1,
	convert);
	if (rc)
	return rc;
	i++;
	}
	} else {
	if (!edst->ptr_leaf) {
	edst->ptr_leaf = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
	GFP_KERNEL);
	if (!edst->ptr_leaf)
	return -ENOMEM;
	}
	i = 0;
	while (i < SIDTAB_LEAF_ENTRIES && *pos < count) {
	rc = convert->func(&esrc->ptr_leaf->entries[i].context,
	&edst->ptr_leaf->entries[i].context,
	convert->args, GFP_KERNEL);
	if (rc)
	return rc;
	(*pos)++;
	i++;
	}
	cond_resched();
	}

	return 0;
	}

	int sidtab_convert(struct sidtab s, struct sidtab_convert_params params)
	{
	unsigned long flags;
	u32 count, level, pos;
	int rc;

	spin_lock_irqsave(&s->lock, flags);

	/* concurrent policy loads are not allowed */
	if (s->convert) {
	spin_unlock_irqrestore(&s->lock, flags);
	return -EBUSY;
	}

	count = s->count;
	level = sidtab_level_from_count(count);

	/* allocate last leaf in the new sidtab (to avoid race with
	* live convert)
	*/
	rc = sidtab_do_lookup(params->target, count - 1, 1) ? 0 : -ENOMEM;
	if (rc) {
	spin_unlock_irqrestore(&s->lock, flags);
	return rc;
	}

	/* set count in case no new entries are added during conversion */
	params->target->count = count;

	/* enable live convert of new entries */
	s->convert = params;

	/* we can safely convert the tree outside the lock */
	spin_unlock_irqrestore(&s->lock, flags);

	pr_info("SELinux: Converting %u SID table entries...\n", count);

	/* convert all entries not covered by live convert */
	pos = 0;
	rc = sidtab_convert_tree(&params->target->roots[level],
	&s->roots[level], &pos, count, level, params);
	if (rc) {
	/* we need to keep the old table - disable live convert */
	spin_lock_irqsave(&s->lock, flags);
	s->convert = NULL;
	spin_unlock_irqrestore(&s->lock, flags);
	return rc;
	}
	/*
	* The hashtable can also be modified in sidtab_context_to_sid()
	* so we must re-acquire the lock here.
	*/
	spin_lock_irqsave(&s->lock, flags);
	sidtab_convert_hashtable(params->target, count);
	spin_unlock_irqrestore(&s->lock, flags);

	return 0;
	}

	static void sidtab_destroy_tree(union sidtab_entry_inner entry, u32 level)
	{
	u32 i;

	if (level != 0) {
	struct sidtab_node_inner *node = entry.ptr_inner;

	if (!node)
	return;

	for (i = 0; i < SIDTAB_INNER_ENTRIES; i++)
	sidtab_destroy_tree(node->entries[i], level - 1);
	kfree(node);
	} else {
	struct sidtab_node_leaf *node = entry.ptr_leaf;

	if (!node)
	return;

	for (i = 0; i < SIDTAB_LEAF_ENTRIES; i++)
	context_destroy(&node->entries[i].context);
	kfree(node);
	}
	}

	void sidtab_destroy(struct sidtab *s)
	{
	u32 i, level;

	for (i = 0; i < SECINITSID_NUM; i++)
	if (s->isids[i].set)
	context_destroy(&s->isids[i].leaf.context);

	level = SIDTAB_MAX_LEVEL;
	while (level && !s->roots[level].ptr_inner)
	--level;

	sidtab_destroy_tree(s->roots[level], level);
	/*
	* The context_to_sid hashtable's objects are all shared
	* with the isids array and context tree, and so don't need
	* to be cleaned up here.
	*/
	}