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 D0A53EB64DB for ; Thu, 15 Jun 2023 09:08:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245427AbjFOJIu (ORCPT ); Thu, 15 Jun 2023 05:08:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46440 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245385AbjFOJIp (ORCPT ); Thu, 15 Jun 2023 05:08:45 -0400 Received: from out30-101.freemail.mail.aliyun.com (out30-101.freemail.mail.aliyun.com [115.124.30.101]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A82741FE8; Thu, 15 Jun 2023 02:08:37 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R141e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046051;MF=tianjia.zhang@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0Vl9wwvH_1686820112; Received: from 30.240.108.67(mailfrom:tianjia.zhang@linux.alibaba.com fp:SMTPD_---0Vl9wwvH_1686820112) by smtp.aliyun-inc.com; Thu, 15 Jun 2023 17:08:34 +0800 Message-ID: <66c72938-912c-5167-fdb1-bffefe1db0c9@linux.alibaba.com> Date: Thu, 15 Jun 2023 17:08:31 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH v2] integrity: Fix possible multiple allocation in integrity_inode_get() To: Jarkko Sakkinen , Mimi Zohar , Dmitry Kasatkin , Paul Moore , James Morris , "Serge E. Hallyn" , linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org References: <20230530121453.10249-1-tianjia.zhang@linux.alibaba.com> <20230601064244.33633-1-tianjia.zhang@linux.alibaba.com> Content-Language: en-US From: Tianjia Zhang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: Hi Jarkko, On 6/9/23 10:24 PM, Jarkko Sakkinen wrote: > On Thu Jun 1, 2023 at 9:42 AM EEST, Tianjia Zhang wrote: >> When integrity_inode_get() is querying and inserting the cache, there >> is a conditional race in the concurrent environment. >> >> The race condition is the result of not properly implementing >> "double-checked locking". In this case, it first checks to see if the >> iint cache record exists before taking the lock, but doesn't check >> again after taking the integrity_iint_lock. >> >> Fixes: bf2276d10ce5 ("ima: allocating iint improvements") >> Signed-off-by: Tianjia Zhang >> Cc: Dmitry Kasatkin >> Cc: # v3.10+ > > s/v3.10/v4.14/ > > I.e. cover only currently maintained longterms, right? > Yes, the race condition was indeed introduced in 3.10, but the fix is estimated to only cover the LTS version. > >> --- >> security/integrity/iint.c | 15 +++++++++------ >> 1 file changed, 9 insertions(+), 6 deletions(-) >> >> diff --git a/security/integrity/iint.c b/security/integrity/iint.c >> index c73858e8c6d5..a462df827de2 100644 >> --- a/security/integrity/iint.c >> +++ b/security/integrity/iint.c >> @@ -43,12 +43,10 @@ static struct integrity_iint_cache *__integrity_iint_find(struct inode *inode) >> else if (inode > iint->inode) >> n = n->rb_right; >> else >> - break; >> + return iint; >> } >> - if (!n) >> - return NULL; >> >> - return iint; >> + return NULL; >> } >> >> /* >> @@ -113,10 +111,15 @@ struct integrity_iint_cache *integrity_inode_get(struct inode *inode) >> parent = *p; >> test_iint = rb_entry(parent, struct integrity_iint_cache, >> rb_node); >> - if (inode < test_iint->inode) >> + if (inode < test_iint->inode) { >> p = &(*p)->rb_left; >> - else >> + } else if (inode > test_iint->inode) { >> p = &(*p)->rb_right; >> + } else { >> + write_unlock(&integrity_iint_lock); >> + kmem_cache_free(iint_cache, iint); >> + return test_iint; >> + } >> } >> >> iint->inode = inode; >> -- >> 2.24.3 (Apple Git-128) > > Mimi, are you picking this? Mimi has picked this patch in next-integrity. > > Off-topic: how do you compile kernel on macOS, you're using VM right? > I'm just interested because I recently bought Mac mini for both > compiling and testing arm64. Optimal would be to be able to compile > the kernel on bare metal and then deploy to a VM... > I am currently only coding and sending the final patch on a Mac. Compilation and testing are still carried out in the linux environment. If you have experience in launching a linux VM on macOS, please share it with me, thanks. Best regards, Tianjia