From patchwork Thu May 23 15:18:04 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 10957997 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D0D3076 for ; Thu, 23 May 2019 15:18:13 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BDA2328630 for ; Thu, 23 May 2019 15:18:13 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BC01A2863C; Thu, 23 May 2019 15:18:13 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3F9B928683 for ; Thu, 23 May 2019 15:18:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731063AbfEWPSI (ORCPT ); Thu, 23 May 2019 11:18:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57344 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730899AbfEWPSH (ORCPT ); Thu, 23 May 2019 11:18:07 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B4D9B3019882; Thu, 23 May 2019 15:18:06 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-121-142.rdu2.redhat.com [10.10.121.142]) by smtp.corp.redhat.com (Postfix) with ESMTP id 17BFB1802F; Thu, 23 May 2019 15:18:04 +0000 (UTC) Organization: Red Hat UK Ltd. 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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 2/9] keys: Cache the hash value to avoid lots of recalculation [ver #3] From: David Howells To: ebiederm@xmission.com Cc: dhowells@redhat.com, dwalsh@redhat.com, vgoyal@redhat.com, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Date: Thu, 23 May 2019 16:18:04 +0100 Message-ID: <155862468433.15244.10730708295650659853.stgit@warthog.procyon.org.uk> In-Reply-To: <155862466770.15244.16038372267332150004.stgit@warthog.procyon.org.uk> References: <155862466770.15244.16038372267332150004.stgit@warthog.procyon.org.uk> User-Agent: StGit/unknown-version MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Thu, 23 May 2019 15:18:06 +0000 (UTC) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Cache the hash of the key's type and description in the index key so that we're not recalculating it every time we look at a key during a search. The hash function does a bunch of multiplications, so evading those is probably worthwhile - especially as this is done for every key examined during a search. This also allows the methods used by assoc_array to get chunks of index-key to be simplified. Signed-off-by: David Howells --- include/linux/key.h | 3 +++ security/keys/internal.h | 8 +------- security/keys/key.c | 2 +- security/keys/keyring.c | 28 ++++++++++++++++++++-------- 4 files changed, 25 insertions(+), 16 deletions(-) diff --git a/include/linux/key.h b/include/linux/key.h index 86ccc2d010f6..fb2debcacea0 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -86,6 +86,8 @@ struct keyring_list; struct keyring_name; struct keyring_index_key { + /* [!] If this structure is altered, the union in struct key must change too! */ + unsigned long hash; /* Hash value */ union { struct { #ifdef __LITTLE_ENDIAN /* Put desc_len at the LSB of x */ @@ -213,6 +215,7 @@ struct key { union { struct keyring_index_key index_key; struct { + unsigned long hash; unsigned long len_desc; struct key_type *type; /* type of key */ char *description; diff --git a/security/keys/internal.h b/security/keys/internal.h index de4fbf6afd89..b7a20929e803 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -89,13 +89,7 @@ extern spinlock_t key_serial_lock; extern struct mutex key_construction_mutex; extern wait_queue_head_t request_key_conswq; - -static inline void key_set_index_key(struct keyring_index_key *index_key) -{ - size_t n = min_t(size_t, index_key->desc_len, sizeof(index_key->desc)); - memcpy(index_key->desc, index_key->description, n); -} - +extern void key_set_index_key(struct keyring_index_key *index_key); extern struct key_type *key_type_lookup(const char *type); extern void key_type_put(struct key_type *ktype); diff --git a/security/keys/key.c b/security/keys/key.c index 010d57859446..0741024bafe6 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -285,12 +285,12 @@ struct key *key_alloc(struct key_type *type, const char *desc, key->index_key.description = kmemdup(desc, desclen + 1, GFP_KERNEL); if (!key->index_key.description) goto no_memory_3; + key->index_key.type = type; key_set_index_key(&key->index_key); refcount_set(&key->usage, 1); init_rwsem(&key->sem); lockdep_set_class(&key->sem, &type->lock_class); - key->index_key.type = type; key->user = user; key->quotalen = quotalen; key->datalen = type->def_datalen; diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 95fb1d90a22c..13841b00ed6f 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -168,7 +168,7 @@ static u64 mult_64x32_and_fold(u64 x, u32 y) /* * Hash a key type and description. */ -static unsigned long hash_key_type_and_desc(const struct keyring_index_key *index_key) +static void hash_key_type_and_desc(struct keyring_index_key *index_key) { const unsigned level_shift = ASSOC_ARRAY_LEVEL_STEP; const unsigned long fan_mask = ASSOC_ARRAY_FAN_MASK; @@ -206,10 +206,22 @@ static unsigned long hash_key_type_and_desc(const struct keyring_index_key *inde * zero for keyrings and non-zero otherwise. */ if (index_key->type != &key_type_keyring && (hash & fan_mask) == 0) - return hash | (hash >> (ASSOC_ARRAY_KEY_CHUNK_SIZE - level_shift)) | 1; - if (index_key->type == &key_type_keyring && (hash & fan_mask) != 0) - return (hash + (hash << level_shift)) & ~fan_mask; - return hash; + hash |= (hash >> (ASSOC_ARRAY_KEY_CHUNK_SIZE - level_shift)) | 1; + else if (index_key->type == &key_type_keyring && (hash & fan_mask) != 0) + hash = (hash + (hash << level_shift)) & ~fan_mask; + index_key->hash = hash; +} + +/* + * Finalise an index key to include a part of the description actually in the + * index key and to add in the hash too. + */ +void key_set_index_key(struct keyring_index_key *index_key) +{ + size_t n = min_t(size_t, index_key->desc_len, sizeof(index_key->desc)); + memcpy(index_key->desc, index_key->description, n); + + hash_key_type_and_desc(index_key); } /* @@ -227,7 +239,7 @@ static unsigned long keyring_get_key_chunk(const void *data, int level) level /= ASSOC_ARRAY_KEY_CHUNK_SIZE; switch (level) { case 0: - return hash_key_type_and_desc(index_key); + return index_key->hash; case 1: return index_key->x; case 2: @@ -280,8 +292,8 @@ static int keyring_diff_objects(const void *object, const void *data) int level, i; level = 0; - seg_a = hash_key_type_and_desc(a); - seg_b = hash_key_type_and_desc(b); + seg_a = a->hash; + seg_b = b->hash; if ((seg_a ^ seg_b) != 0) goto differ; level += ASSOC_ARRAY_KEY_CHUNK_SIZE / 8;