selinux: Add a cache for quicker retreival of PKey SIDs (409dcf31) · Commits · 方亚芬 / raspberrypi_linux

security/selinux/Makefile

+1 −1

Original line number	Diff line number	Diff line
		@@ -5,7 +5,7 @@
		obj-$(CONFIG_SECURITY_SELINUX) := selinux.o

		selinux-y := avc.o hooks.o selinuxfs.o netlink.o nlmsgtab.o netif.o \
		netnode.o netport.o exports.o \
		netnode.o netport.o ibpkey.o exports.o \
		ss/ebitmap.o ss/hashtab.o ss/symtab.o ss/sidtab.o ss/avtab.o \
		ss/policydb.o ss/services.o ss/conditional.o ss/mls.o ss/status.o

security/selinux/hooks.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -91,6 +91,7 @@
		#include "netif.h"
		#include "netnode.h"
		#include "netport.h"
		#include "ibpkey.h"
		#include "xfrm.h"
		#include "netlabel.h"
		#include "audit.h"
		@@ -174,8 +175,10 @@ static int selinux_netcache_avc_callback(u32 event)

		static int selinux_lsm_notifier_avc_callback(u32 event)
		{
		if (event == AVC_CALLBACK_RESET)
		if (event == AVC_CALLBACK_RESET) {
		sel_ib_pkey_flush();
		call_lsm_notifier(LSM_POLICY_CHANGE, NULL);
		}

		return 0;
		}
		@@ -6156,7 +6159,7 @@ static int selinux_ib_pkey_access(void *ib_sec, u64 subnet_prefix, u16 pkey_val)
		struct ib_security_struct *sec = ib_sec;
		struct lsm_ibpkey_audit ibpkey;

		err = security_ib_pkey_sid(subnet_prefix, pkey_val, &sid);
		err = sel_ib_pkey_sid(subnet_prefix, pkey_val, &sid);
		if (err)
		return err;

security/selinux/ibpkey.c

0 → 100644

+245 −0

Original line number	Diff line number	Diff line
		/*
		* Pkey table
		*
		* SELinux must keep a mapping of Infinband PKEYs to labels/SIDs. This
		* mapping is maintained as part of the normal policy but a fast cache is
		* needed to reduce the lookup overhead.
		*
		* This code is heavily based on the "netif" and "netport" concept originally
		* developed by
		* James Morris <jmorris@redhat.com> and
		* Paul Moore <paul@paul-moore.com>
		* (see security/selinux/netif.c and security/selinux/netport.c for more
		* information)
		*
		*/

		/*
		* (c) Mellanox Technologies, 2016
		*
		* This program is free software: you can redistribute it and/or modify
		* it under the terms of version 2 of the GNU General Public License as
		* published by the Free Software Foundation.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		*/

		#include <linux/types.h>
		#include <linux/rcupdate.h>
		#include <linux/list.h>
		#include <linux/spinlock.h>

		#include "ibpkey.h"
		#include "objsec.h"

		#define SEL_PKEY_HASH_SIZE 256
		#define SEL_PKEY_HASH_BKT_LIMIT 16

		struct sel_ib_pkey_bkt {
		int size;
		struct list_head list;
		};

		struct sel_ib_pkey {
		struct pkey_security_struct psec;
		struct list_head list;
		struct rcu_head rcu;
		};

		static LIST_HEAD(sel_ib_pkey_list);
		static DEFINE_SPINLOCK(sel_ib_pkey_lock);
		static struct sel_ib_pkey_bkt sel_ib_pkey_hash[SEL_PKEY_HASH_SIZE];

		/**
		* sel_ib_pkey_hashfn - Hashing function for the pkey table
		* @pkey: pkey number
		*
		* Description:
		* This is the hashing function for the pkey table, it returns the bucket
		* number for the given pkey.
		*
		*/
		static unsigned int sel_ib_pkey_hashfn(u16 pkey)
		{
		return (pkey & (SEL_PKEY_HASH_SIZE - 1));
		}

		/**
		* sel_ib_pkey_find - Search for a pkey record
		* @subnet_prefix: subnet_prefix
		* @pkey_num: pkey_num
		*
		* Description:
		* Search the pkey table and return the matching record. If an entry
		* can not be found in the table return NULL.
		*
		*/
		static struct sel_ib_pkey *sel_ib_pkey_find(u64 subnet_prefix, u16 pkey_num)
		{
		unsigned int idx;
		struct sel_ib_pkey *pkey;

		idx = sel_ib_pkey_hashfn(pkey_num);
		list_for_each_entry_rcu(pkey, &sel_ib_pkey_hash[idx].list, list) {
		if (pkey->psec.pkey == pkey_num &&
		pkey->psec.subnet_prefix == subnet_prefix)
		return pkey;
		}

		return NULL;
		}

		/**
		* sel_ib_pkey_insert - Insert a new pkey into the table
		* @pkey: the new pkey record
		*
		* Description:
		* Add a new pkey record to the hash table.
		*
		*/
		static void sel_ib_pkey_insert(struct sel_ib_pkey *pkey)
		{
		unsigned int idx;

		/* we need to impose a limit on the growth of the hash table so check
		* this bucket to make sure it is within the specified bounds
		*/
		idx = sel_ib_pkey_hashfn(pkey->psec.pkey);
		list_add_rcu(&pkey->list, &sel_ib_pkey_hash[idx].list);
		if (sel_ib_pkey_hash[idx].size == SEL_PKEY_HASH_BKT_LIMIT) {
		struct sel_ib_pkey *tail;

		tail = list_entry(
		rcu_dereference_protected(
		sel_ib_pkey_hash[idx].list.prev,
		lockdep_is_held(&sel_ib_pkey_lock)),
		struct sel_ib_pkey, list);
		list_del_rcu(&tail->list);
		kfree_rcu(tail, rcu);
		} else {
		sel_ib_pkey_hash[idx].size++;
		}
		}

		/**
		* sel_ib_pkey_sid_slow - Lookup the SID of a pkey using the policy
		* @subnet_prefix: subnet prefix
		* @pkey_num: pkey number
		* @sid: pkey SID
		*
		* Description:
		* This function determines the SID of a pkey by querying the security
		* policy. The result is added to the pkey table to speedup future
		* queries. Returns zero on success, negative values on failure.
		*
		*/
		static int sel_ib_pkey_sid_slow(u64 subnet_prefix, u16 pkey_num, u32 *sid)
		{
		int ret;
		struct sel_ib_pkey *pkey;
		struct sel_ib_pkey *new = NULL;
		unsigned long flags;

		spin_lock_irqsave(&sel_ib_pkey_lock, flags);
		pkey = sel_ib_pkey_find(subnet_prefix, pkey_num);
		if (pkey) {
		*sid = pkey->psec.sid;
		spin_unlock_irqrestore(&sel_ib_pkey_lock, flags);
		return 0;
		}

		ret = security_ib_pkey_sid(subnet_prefix, pkey_num, sid);
		if (ret)
		goto out;

		/* If this memory allocation fails still return 0. The SID
		* is valid, it just won't be added to the cache.
		*/
		new = kzalloc(sizeof(*new), GFP_ATOMIC);
		if (!new)
		goto out;

		new->psec.subnet_prefix = subnet_prefix;
		new->psec.pkey = pkey_num;
		new->psec.sid = *sid;
		sel_ib_pkey_insert(new);

		out:
		spin_unlock_irqrestore(&sel_ib_pkey_lock, flags);
		return ret;
		}

		/**
		* sel_ib_pkey_sid - Lookup the SID of a PKEY
		* @subnet_prefix: subnet_prefix
		* @pkey_num: pkey number
		* @sid: pkey SID
		*
		* Description:
		* This function determines the SID of a PKEY using the fastest method
		* possible. First the pkey table is queried, but if an entry can't be found
		* then the policy is queried and the result is added to the table to speedup
		* future queries. Returns zero on success, negative values on failure.
		*
		*/
		int sel_ib_pkey_sid(u64 subnet_prefix, u16 pkey_num, u32 *sid)
		{
		struct sel_ib_pkey *pkey;

		rcu_read_lock();
		pkey = sel_ib_pkey_find(subnet_prefix, pkey_num);
		if (pkey) {
		*sid = pkey->psec.sid;
		rcu_read_unlock();
		return 0;
		}
		rcu_read_unlock();

		return sel_ib_pkey_sid_slow(subnet_prefix, pkey_num, sid);
		}

		/**
		* sel_ib_pkey_flush - Flush the entire pkey table
		*
		* Description:
		* Remove all entries from the pkey table
		*
		*/
		void sel_ib_pkey_flush(void)
		{
		unsigned int idx;
		struct sel_ib_pkey pkey, pkey_tmp;
		unsigned long flags;

		spin_lock_irqsave(&sel_ib_pkey_lock, flags);
		for (idx = 0; idx < SEL_PKEY_HASH_SIZE; idx++) {
		list_for_each_entry_safe(pkey, pkey_tmp,
		&sel_ib_pkey_hash[idx].list, list) {
		list_del_rcu(&pkey->list);
		kfree_rcu(pkey, rcu);
		}
		sel_ib_pkey_hash[idx].size = 0;
		}
		spin_unlock_irqrestore(&sel_ib_pkey_lock, flags);
		}

		static __init int sel_ib_pkey_init(void)
		{
		int iter;

		if (!selinux_enabled)
		return 0;

		for (iter = 0; iter < SEL_PKEY_HASH_SIZE; iter++) {
		INIT_LIST_HEAD(&sel_ib_pkey_hash[iter].list);
		sel_ib_pkey_hash[iter].size = 0;
		}

		return 0;
		}

		subsys_initcall(sel_ib_pkey_init);

security/selinux/include/ibpkey.h

0 → 100644

+31 −0

Original line number	Diff line number	Diff line
		/*
		* pkey table
		*
		* SELinux must keep a mapping of pkeys to labels/SIDs. This
		* mapping is maintained as part of the normal policy but a fast cache is
		* needed to reduce the lookup overhead.
		*
		*/

		/*
		* (c) Mellanox Technologies, 2016
		*
		* This program is free software: you can redistribute it and/or modify
		* it under the terms of version 2 of the GNU General Public License as
		* published by the Free Software Foundation.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		*/

		#ifndef _SELINUX_IB_PKEY_H
		#define _SELINUX_IB_PKEY_H

		void sel_ib_pkey_flush(void);

		int sel_ib_pkey_sid(u64 subnet_prefix, u16 pkey, u32 *sid);

		#endif

security/selinux/include/objsec.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -144,6 +144,12 @@ struct ib_security_struct {
		u32 sid; /* SID of the queue pair or MAD agent */
		};

		struct pkey_security_struct {
		u64 subnet_prefix; /* Port subnet prefix */
		u16 pkey; /* PKey number */
		u32 sid; /* SID of pkey */
		};

		extern unsigned int selinux_checkreqprot;

		#endif /* _SELINUX_OBJSEC_H_ */