From patchwork Fri Jul 21 16:33:17 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 13322372 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19A0BEB64DD for ; Fri, 21 Jul 2023 16:53:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230311AbjGUQxi (ORCPT ); Fri, 21 Jul 2023 12:53:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49710 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229533AbjGUQxg (ORCPT ); Fri, 21 Jul 2023 12:53:36 -0400 Received: from frasgout11.his.huawei.com (unknown [14.137.139.23]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1283A2727; Fri, 21 Jul 2023 09:53:35 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.18.147.229]) by frasgout11.his.huawei.com (SkyGuard) with ESMTP id 4R6vx72s5wz9xFQJ; Sat, 22 Jul 2023 00:23:07 +0800 (CST) Received: from huaweicloud.com (unknown [10.204.63.22]) by APP2 (Coremail) with SMTP id GxC2BwC3hl1bs7pkcDDSBA--.22409S5; Fri, 21 Jul 2023 17:34:02 +0100 (CET) From: Roberto Sassu To: zohar@linux.ibm.com, dmitry.kasatkin@gmail.com, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com Cc: linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, bpf@vger.kernel.org, jarkko@kernel.org, pbrobinson@gmail.com, zbyszek@in.waw.pl, hch@lst.de, mjg59@srcf.ucam.org, Roberto Sassu Subject: [RFC][PATCH 03/12] integrity/digest_cache: Add functions to populate and search Date: Fri, 21 Jul 2023 18:33:17 +0200 Message-Id: <20230721163326.4106089-4-roberto.sassu@huaweicloud.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230721163326.4106089-1-roberto.sassu@huaweicloud.com> References: <20230721163326.4106089-1-roberto.sassu@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: GxC2BwC3hl1bs7pkcDDSBA--.22409S5 X-Coremail-Antispam: 1UD129KBjvJXoWxtr43Cr1DWFyUtFWUKw4kJFb_yoWxJw1kpa s7Cr1Utr4rZF13Gw1xAF1ayr1FvrWqqF47Jw45Wr1ayr4DXr1jy3W8Aw1UXFy5Jr48Wa17 tF4jgr1Uur1UXaUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPqb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUWw A2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVW8JVW5JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV W8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_Gr0_Cr1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6r4UJVWxJr1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2 WlYx0E2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkE bVWUJVW8JwACjcxG0xvY0x0EwIxGrwACI402YVCY1x02628vn2kIc2xKxwCY1x0262kKe7 AKxVW8ZVWrXwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02 F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GF ylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVW8JVW5JwCI42IY6xIIjxv20xvEc7Cj xVAFwI0_Gr1j6F4UJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI 0_Gr0_Cr1lIxAIcVC2z280aVCY1x0267AKxVW8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x 07jzE__UUUUU= X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAQAFBF1jj5DJQAAAso X-CFilter-Loop: Reflected Precedence: bulk List-ID: From: Roberto Sassu Add digest_cache_init_htable(), to size a hash table depending on the number of digests to be added to the cache. Add digest_cache_add() and digest_cache_lookup() to respectively add and lookup a digest in the digest cache. Signed-off-by: Roberto Sassu --- security/integrity/digest_cache.c | 124 ++++++++++++++++++++++++++++++ security/integrity/digest_cache.h | 24 ++++++ 2 files changed, 148 insertions(+) diff --git a/security/integrity/digest_cache.c b/security/integrity/digest_cache.c index 66c2c4088e9..7537c7232db 100644 --- a/security/integrity/digest_cache.c +++ b/security/integrity/digest_cache.c @@ -298,3 +298,127 @@ void digest_cache_put(struct digest_cache *digest_cache, pr_debug("Put cache, algo: %s, digest list: %s", hash_algo_name[digest_cache->algo], digest_cache->path_str); } + +/** + * digest_cache_init_htable - Allocate and initialize the hash table + * @digest_cache: Digest cache + * @num_digests: Number of digests to add to the digest cache + * + * This function allocates and initializes the hash table. Its size is + * determined by the number of digests to add to the digest cache, known + * at this point by the parser calling this function. + * + * Return: Zero on success, a negative value otherwise. + */ +int digest_cache_init_htable(struct digest_cache *digest_cache, + u64 num_digests) +{ + int i; + + if (!digest_cache) + return 0; + + digest_cache->num_slots = num_digests / DIGEST_CACHE_HTABLE_DEPTH; + if (!digest_cache->num_slots) + digest_cache->num_slots = 1; + + digest_cache->slots = kmalloc_array(num_digests, + sizeof(*digest_cache->slots), + GFP_KERNEL); + if (!digest_cache->slots) + return -ENOMEM; + + for (i = 0; i < digest_cache->num_slots; i++) + INIT_HLIST_HEAD(&digest_cache->slots[i]); + + pr_debug("Initialized %d hash table slots for digest list %s\n", + digest_cache->num_slots, digest_cache->path_str); + return 0; +} + +/** + * digest_cache_add - Add a new digest to the digest cache + * @digest_cache: Digest cache + * @digest: Digest to add + * + * This function, invoked by a digest list parser, adds a digest extracted + * from a digest list to the digest cache. + * + * Return: Zero on success, a negative value on error. + */ +int digest_cache_add(struct digest_cache *digest_cache, u8 *digest) +{ + struct digest_cache_entry *entry; + unsigned int key; + int digest_len; + + if (!digest_cache) + return 0; + + digest_len = hash_digest_size[digest_cache->algo]; + + entry = kmalloc(sizeof(*entry) + digest_len, GFP_KERNEL); + if (!entry) + return -ENOMEM; + + memcpy(entry->digest, digest, digest_len); + + key = digest_cache_hash_key(digest, digest_cache->num_slots); + hlist_add_head(&entry->hnext, &digest_cache->slots[key]); + pr_debug("Add digest %s:%*phN from digest list %s\n", + hash_algo_name[digest_cache->algo], digest_len, digest, + digest_cache->path_str); + return 0; +} + +/** + * digest_cache_lookup - Searches a digest in the digest cache + * @digest_cache: Digest cache + * @digest: Digest to search + * @algo: Algorithm of the digest to search + * + * This function, invoked by IMA or EVM, searches the calculated digest of + * a file or file metadata in the digest cache acquired with + * digest_cache_get(). + * + * Return: Zero if the digest is found, a negative value if not. + */ +int digest_cache_lookup(struct digest_cache *digest_cache, u8 *digest, + enum hash_algo algo, const char *pathname) +{ + struct digest_cache_entry *entry; + unsigned int key; + int digest_len; + int search_depth = 0; + + if (!digest_cache) + return -ENOENT; + + digest_len = hash_digest_size[digest_cache->algo]; + + if (algo != digest_cache->algo) { + pr_debug("Algo mismatch for file %s, digest %s:%*phN in digest list %s (*%s)\n", + pathname, hash_algo_name[algo], digest_len, digest, + digest_cache->path_str, + hash_algo_name[digest_cache->algo]); + return -ENOENT; + } + + key = digest_cache_hash_key(digest, digest_cache->num_slots); + + hlist_for_each_entry_rcu(entry, &digest_cache->slots[key], hnext) { + if (!memcmp(entry->digest, digest, digest_len)) { + pr_debug("Cache hit at depth %d for file %s, digest %s:%*phN in digest list %s\n", + search_depth, pathname, hash_algo_name[algo], digest_len, + digest, digest_cache->path_str); + return 0; + } + + search_depth++; + } + + pr_debug("Cache miss for file %s, digest %s:%*phN in digest list %s\n", + pathname, hash_algo_name[algo], digest_len, digest, + digest_cache->path_str); + return -ENOENT; +} diff --git a/security/integrity/digest_cache.h b/security/integrity/digest_cache.h index fa4a716df65..5e3997b2723 100644 --- a/security/integrity/digest_cache.h +++ b/security/integrity/digest_cache.h @@ -64,6 +64,11 @@ struct digest_cache *digest_cache_get(struct dentry *dentry, struct path *digest_list_path); void digest_cache_put(struct digest_cache *digest_cache, struct path *digest_list_path); +int digest_cache_init_htable(struct digest_cache *digest_cache, + u64 num_digests); +int digest_cache_add(struct digest_cache *digest_cache, u8 *digest); +int digest_cache_lookup(struct digest_cache *digest_cache, u8 *digest, + enum hash_algo algo, const char *pathname); #else static inline void digest_cache_free(struct digest_cache *digest_cache) { @@ -80,5 +85,24 @@ static inline void digest_cache_put(struct digest_cache *digest_cache, { } +static inline int digest_cache_init_htable(struct digest_cache *digest_cache, + u64 num_digests) +{ + return -EOPNOTSUPP; +} + +static inline int digest_cache_add(struct digest_cache *digest_cache, + u8 *digest) +{ + return -EOPNOTSUPP; +} + +static inline int digest_cache_lookup(struct digest_cache *digest_cache, + u8 *digest, enum hash_algo algo, + const char *pathname) +{ + return -ENOENT; +} + #endif /* CONFIG_INTEGRITY_DIGEST_CACHE */ #endif /* _DIGEST_CACHE_H */