From mboxrd@z Thu Jan 1 00:00:00 1970 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 CF97EC433FE for ; Wed, 15 Dec 2021 02:54:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239419AbhLOCys (ORCPT ); Tue, 14 Dec 2021 21:54:48 -0500 Received: from szxga02-in.huawei.com ([45.249.212.188]:16810 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239418AbhLOCyq (ORCPT ); Tue, 14 Dec 2021 21:54:46 -0500 Received: from dggpeml500023.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4JDKZc5W7wz91Zh; Wed, 15 Dec 2021 10:54:00 +0800 (CST) Received: from [10.67.110.112] (10.67.110.112) by dggpeml500023.china.huawei.com (7.185.36.114) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Wed, 15 Dec 2021 10:54:44 +0800 Subject: Re: [PATCH -next] audit: use struct_size() helper in kmalloc() To: "Gustavo A. R. Silva" CC: , , , , , , References: <20211214114854.133328-1-xiujianfeng@huawei.com> <20211214175448.GA13107@embeddedor> From: xiujianfeng Message-ID: <8304d0db-c1b1-ceca-4f6f-d1fe5d486a1e@huawei.com> Date: Wed, 15 Dec 2021 10:54:44 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.9.1 MIME-Version: 1.0 In-Reply-To: <20211214175448.GA13107@embeddedor> Content-Type: text/plain; charset="gbk"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.67.110.112] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpeml500023.china.huawei.com (7.185.36.114) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ÔÚ 2021/12/15 1:54, Gustavo A. R. Silva дµÀ: > On Tue, Dec 14, 2021 at 07:48:54PM +0800, Xiu Jianfeng wrote: >> Make use of struct_size() helper instead of an open-coded calucation. >> >> Link: https://github.com/KSPP/linux/issues/160 >> Signed-off-by: Xiu Jianfeng >> --- >> kernel/audit.c | 2 +- >> kernel/audit_tree.c | 2 +- >> kernel/auditfilter.c | 2 +- >> 3 files changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/kernel/audit.c b/kernel/audit.c >> index d4084751cfe6..f33028578c60 100644 >> --- a/kernel/audit.c >> +++ b/kernel/audit.c >> @@ -1446,7 +1446,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) >> if (err) >> return err; >> } >> - sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL); >> + sig_data = kmalloc(struct_size(sig_data, ctx, len), GFP_KERNEL); >> if (!sig_data) { >> if (audit_sig_sid) >> security_release_secctx(ctx, len); >> diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c >> index 72324afcffef..e7315d487163 100644 >> --- a/kernel/audit_tree.c >> +++ b/kernel/audit_tree.c >> @@ -94,7 +94,7 @@ static struct audit_tree *alloc_tree(const char *s) >> { >> struct audit_tree *tree; >> >> - tree = kmalloc(sizeof(struct audit_tree) + strlen(s) + 1, GFP_KERNEL); >> + tree = kmalloc(struct_size(tree, pathname, strlen(s) + 1), GFP_KERNEL); >> if (tree) { >> refcount_set(&tree->count, 1); >> tree->goner = 0; >> diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c >> index 4173e771650c..19352820b274 100644 >> --- a/kernel/auditfilter.c >> +++ b/kernel/auditfilter.c >> @@ -637,7 +637,7 @@ static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule) >> void *bufp; >> int i; >> >> - data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL); >> + data = kmalloc(struct_size(data, buf, krule->buflen), GFP_KERNEL); > Why don't you also transform the zero-length array in struct > audit_rule_data into a flexible-array member: > > 508 struct audit_rule_data { > 509 __u32 flags; /* AUDIT_PER_{TASK,CALL}, AUDIT_PREPEND */ > 510 __u32 action; /* AUDIT_NEVER, AUDIT_POSSIBLE, AUDIT_ALWAYS */ > 511 __u32 field_count; > 512 __u32 mask[AUDIT_BITMASK_SIZE]; /* syscall(s) affected */ > 513 __u32 fields[AUDIT_MAX_FIELDS]; > 514 __u32 values[AUDIT_MAX_FIELDS]; > 515 __u32 fieldflags[AUDIT_MAX_FIELDS]; > 516 __u32 buflen; /* total length of string fields */ > 517 char buf[0]; /* string fields buffer */ > 518 }; > > Thanks > -- > Gustavo thank you, I will add it in the v2 patch. >> if (unlikely(!data)) >> return NULL; >> memset(data, 0, sizeof(*data)); >> -- >> 2.17.1 >> >> >> >> > .