From patchwork Tue Apr 19 19:51:24 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Jurgens X-Patchwork-Id: 8882981 Return-Path: X-Original-To: patchwork-linux-rdma@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id B52DABF29F for ; Tue, 19 Apr 2016 19:52:51 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5927F2024D for ; Tue, 19 Apr 2016 19:52:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0134520204 for ; Tue, 19 Apr 2016 19:52:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933329AbcDSTwr (ORCPT ); Tue, 19 Apr 2016 15:52:47 -0400 Received: from [193.47.165.129] ([193.47.165.129]:39772 "EHLO mellanox.co.il" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S932832AbcDSTwr (ORCPT ); Tue, 19 Apr 2016 15:52:47 -0400 Received: from Internal Mail-Server by MTLPINE1 (envelope-from danielj@mellanox.com) with ESMTPS (AES256-SHA encrypted); 19 Apr 2016 22:51:56 +0300 Received: from x-vnc01.mtx.labs.mlnx (x-vnc01.mtx.labs.mlnx [10.12.150.16]) by labmailer.mlnx (8.13.8/8.13.8) with ESMTP id u3JJph1f011960; Tue, 19 Apr 2016 22:51:55 +0300 From: Dan Jurgens To: selinux@tycho.nsa.gov, linux-security-module@vger.kernel.org, linux-rdma@vger.kernel.org Cc: yevgenyp@mellanox.com, Daniel Jurgens Subject: [RFC PATCH v3 07/12] selinux: Add a cache for quicker retreival of PKey SIDs Date: Tue, 19 Apr 2016 22:51:24 +0300 Message-Id: <1461095489-18732-8-git-send-email-danielj@mellanox.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1461095489-18732-1-git-send-email-danielj@mellanox.com> References: <1461095489-18732-1-git-send-email-danielj@mellanox.com> Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org X-Spam-Status: No, score=-7.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Daniel Jurgens It is likely that the SID for the same PKey will be requested many times. To reduce the time to modify QPs and process MADs use a cache to store PKey SIDs. This code is heavily based on the "netif" and "netport" concept originally developed by James Morris and Paul Moore (see security/selinux/netif.c and security/selinux/netport.c for more information) Signed-off-by: Daniel Jurgens Reviewed-by: Eli Cohen --- v2: No change v3: 1. Try to find in cache after obtaining the spin lock in sel_pkey_sid_slow 2. Don't fail if the mem allocation for the new cache entry fails, return the retrieved SID. --- security/selinux/Makefile | 2 +- security/selinux/hooks.c | 5 +- security/selinux/include/objsec.h | 6 + security/selinux/include/pkey.h | 31 +++++ security/selinux/pkey.c | 243 +++++++++++++++++++++++++++++++++++++ 5 files changed, 285 insertions(+), 2 deletions(-) create mode 100644 security/selinux/include/pkey.h create mode 100644 security/selinux/pkey.c diff --git a/security/selinux/Makefile b/security/selinux/Makefile index 3411c33..a698df4 100644 --- a/security/selinux/Makefile +++ b/security/selinux/Makefile @@ -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 pkey.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 diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 05ce0cc..eeeca14 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -92,6 +92,7 @@ #include "netif.h" #include "netnode.h" #include "netport.h" +#include "pkey.h" #include "xfrm.h" #include "netlabel.h" #include "audit.h" @@ -172,6 +173,8 @@ static int selinux_cache_avc_callback(u32 event) sel_netnode_flush(); sel_netport_flush(); synchronize_net(); + + sel_pkey_flush(); mutex_lock(&ib_flush_mutex); if (ib_flush_callback) ib_flush_callback(); @@ -5966,7 +5969,7 @@ static int selinux_pkey_access(u64 subnet_prefix, u16 pkey_val, void *security) struct ib_security_struct *sec = security; struct lsm_pkey_audit pkey; - err = security_pkey_sid(subnet_prefix, pkey_val, &sid); + err = sel_pkey_sid(subnet_prefix, pkey_val, &sid); if (err) goto out; diff --git a/security/selinux/include/objsec.h b/security/selinux/include/objsec.h index 42f1a6e..d9cc9d3 100644 --- a/security/selinux/include/objsec.h +++ b/security/selinux/include/objsec.h @@ -134,6 +134,12 @@ 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_ */ diff --git a/security/selinux/include/pkey.h b/security/selinux/include/pkey.h new file mode 100644 index 0000000..58a7a3b --- /dev/null +++ b/security/selinux/include/pkey.h @@ -0,0 +1,31 @@ +/* + * 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_H +#define _SELINUX_IB_H + +void sel_pkey_flush(void); + +int sel_pkey_sid(u64 subnet_prefix, u16 pkey, u32 *sid); + +#endif diff --git a/security/selinux/pkey.c b/security/selinux/pkey.c new file mode 100644 index 0000000..565474d --- /dev/null +++ b/security/selinux/pkey.c @@ -0,0 +1,243 @@ +/* + * 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 and + * Paul Moore + * (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 +#include +#include +#include + +#include "pkey.h" +#include "objsec.h" + +#define SEL_PKEY_HASH_SIZE 256 +#define SEL_PKEY_HASH_BKT_LIMIT 16 + +struct sel_pkey_bkt { + int size; + struct list_head list; +}; + +struct sel_pkey { + struct pkey_security_struct psec; + struct list_head list; + struct rcu_head rcu; +}; + +static LIST_HEAD(sel_pkey_list); +static DEFINE_SPINLOCK(sel_pkey_lock); +static struct sel_pkey_bkt sel_pkey_hash[SEL_PKEY_HASH_SIZE]; + +/** + * sel_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_pkey_hashfn(u16 pkey) +{ + return (pkey & (SEL_PKEY_HASH_SIZE - 1)); +} + +/** + * sel_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_pkey *sel_pkey_find(u64 subnet_prefix, u16 pkey_num) +{ + unsigned int idx; + struct sel_pkey *pkey; + + idx = sel_pkey_hashfn(pkey_num); + list_for_each_entry_rcu(pkey, &sel_pkey_hash[idx].list, list) { + if (pkey->psec.pkey == pkey_num && + pkey->psec.subnet_prefix == subnet_prefix) + return pkey; + } + + return NULL; +} + +/** + * sel_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_pkey_insert(struct sel_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_pkey_hashfn(pkey->psec.pkey); + list_add_rcu(&pkey->list, &sel_pkey_hash[idx].list); + if (sel_pkey_hash[idx].size == SEL_PKEY_HASH_BKT_LIMIT) { + struct sel_pkey *tail; + + tail = list_entry( + rcu_dereference_protected( + sel_pkey_hash[idx].list.prev, + lockdep_is_held(&sel_pkey_lock)), + struct sel_pkey, list); + list_del_rcu(&tail->list); + kfree_rcu(tail, rcu); + } else { + sel_pkey_hash[idx].size++; + } +} + +/** + * sel_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_pkey_sid_slow(u64 subnet_prefix, u16 pkey_num, u32 *sid) +{ + int ret = -ENOMEM; + struct sel_pkey *pkey; + struct sel_pkey *new = NULL; + + spin_lock_bh(&sel_pkey_lock); + pkey = sel_pkey_find(subnet_prefix, pkey_num); + if (pkey) { + *sid = pkey->psec.sid; + spin_unlock_bh(&sel_pkey_lock); + return 0; + } + + ret = security_pkey_sid(subnet_prefix, pkey_num, sid); + if (ret != 0) + goto out; + + 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_pkey_insert(new); + +out: + spin_unlock_bh(&sel_pkey_lock); + if (unlikely(ret)) + kfree(new); + + return ret; +} + +/** + * sel_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_pkey_sid(u64 subnet_prefix, u16 pkey_num, u32 *sid) +{ + struct sel_pkey *pkey; + + rcu_read_lock(); + pkey = sel_pkey_find(subnet_prefix, pkey_num); + if (pkey) { + *sid = pkey->psec.sid; + rcu_read_unlock(); + return 0; + } + rcu_read_unlock(); + + return sel_pkey_sid_slow(subnet_prefix, pkey_num, sid); +} + +/** + * sel_pkey_flush - Flush the entire pkey table + * + * Description: + * Remove all entries from the pkey table + * + */ +void sel_pkey_flush(void) +{ + unsigned int idx; + struct sel_pkey *pkey, *pkey_tmp; + + spin_lock_bh(&sel_pkey_lock); + for (idx = 0; idx < SEL_PKEY_HASH_SIZE; idx++) { + list_for_each_entry_safe(pkey, pkey_tmp, + &sel_pkey_hash[idx].list, list) { + list_del_rcu(&pkey->list); + kfree_rcu(pkey, rcu); + } + sel_pkey_hash[idx].size = 0; + } + spin_unlock_bh(&sel_pkey_lock); +} + +static __init int sel_pkey_init(void) +{ + int iter; + + if (!selinux_enabled) + return 0; + + for (iter = 0; iter < SEL_PKEY_HASH_SIZE; iter++) { + INIT_LIST_HEAD(&sel_pkey_hash[iter].list); + sel_pkey_hash[iter].size = 0; + } + + return 0; +} + +subsys_initcall(sel_pkey_init);