From patchwork Sat Aug 12 10:46:06 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 13351790 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 13F79C001DB for ; Sat, 12 Aug 2023 10:48:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236985AbjHLKsL (ORCPT ); Sat, 12 Aug 2023 06:48:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46466 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236988AbjHLKsH (ORCPT ); Sat, 12 Aug 2023 06:48:07 -0400 Received: from frasgout11.his.huawei.com (unknown [14.137.139.23]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 441AB271E; Sat, 12 Aug 2023 03:48:04 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.18.147.228]) by frasgout11.his.huawei.com (SkyGuard) with ESMTP id 4RNHBs3cjgz9yydZ; Sat, 12 Aug 2023 18:36:21 +0800 (CST) Received: from huaweicloud.com (unknown [10.204.63.22]) by APP1 (Coremail) with SMTP id LxC2BwBXC7scY9dkThi9AA--.8440S5; Sat, 12 Aug 2023 11:47:36 +0100 (CET) From: Roberto Sassu To: corbet@lwn.net, 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-doc@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, pmatilai@redhat.com, jannh@google.com, Roberto Sassu Subject: [RFC][PATCH v2 03/13] integrity/digest_cache: Add functions to populate and search Date: Sat, 12 Aug 2023 12:46:06 +0200 Message-Id: <20230812104616.2190095-4-roberto.sassu@huaweicloud.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230812104616.2190095-1-roberto.sassu@huaweicloud.com> References: <20230812104616.2190095-1-roberto.sassu@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: LxC2BwBXC7scY9dkThi9AA--.8440S5 X-Coremail-Antispam: 1UD129KBjvJXoWxtr43XFyDZr17Wr48Gr43trb_yoWxXrW5pa s7Cr1Utr4rZF13Cw17AF1ayr1SvrWqqF47Gw45Wr1ayr4DZr1jy3W8Aw1UXFy5Jr48Wa17 tF4jgr1UCr1UXaUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUB2b4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUWw A2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVWUJVWUCwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV WxJVW8Jr1l84ACjcxK6I8E87Iv67AKxVW8JVWxJwA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_ Gr1j6F4UJwAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ew Av7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY 6r1j6r4UM4x0Y48IcxkI7VAKI48JM4IIrI8v6xkF7I0E8cxan2IY04v7MxAIw28IcxkI7V AKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCj r7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVW8ZVWrXwCIc40Y0x0EwIxGrwCI42IY6x IIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVWxJVW8Jr1lIxAIcVCF 04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r4j6F4UMIIF0xvEx4A2jsIEc7 CjxVAFwI0_Gr1j6F4UJbIYCTnIWIevJa73UjIFyTuYvjxUFYFCUUUUU X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAQAHBF1jj5KVZQAAsR 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 | 131 ++++++++++++++++++++++++++++++ security/integrity/digest_cache.h | 24 ++++++ 2 files changed, 155 insertions(+) diff --git a/security/integrity/digest_cache.c b/security/integrity/digest_cache.c index 4201c68171a..d14d84b804b 100644 --- a/security/integrity/digest_cache.c +++ b/security/integrity/digest_cache.c @@ -315,3 +315,134 @@ struct digest_cache *digest_cache_get(struct dentry *dentry, return iint->dig_user; } + +/** + * 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 + * @pathname: Path of the file whose digest is looked up + * + * 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; + + if (digest_cache->algo == HASH_ALGO__LAST) { + pr_debug("Algorithm not set for digest list %s\n", + digest_cache->path_str); + 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 ff88e8593c6..01cd70f9850 100644 --- a/security/integrity/digest_cache.h +++ b/security/integrity/digest_cache.h @@ -66,6 +66,11 @@ static inline unsigned int digest_cache_hash_key(u8 *digest, void digest_cache_free(struct digest_cache *digest_cache); struct digest_cache *digest_cache_get(struct dentry *dentry, struct integrity_iint_cache *iint); +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) { @@ -77,5 +82,24 @@ digest_cache_get(struct dentry *dentry, struct integrity_iint_cache *iint) return NULL; } +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 */