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 X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 997D4C433E0 for ; Wed, 3 Feb 2021 17:49:26 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C595664F8C for ; Wed, 3 Feb 2021 17:49:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C595664F8C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4DW8M75Vk9zDywl for ; Thu, 4 Feb 2021 04:49:23 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux.microsoft.com (client-ip=13.77.154.182; helo=linux.microsoft.com; envelope-from=nramas@linux.microsoft.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.a=rsa-sha256 header.s=default header.b=ajqWrUw9; dkim-atps=neutral Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lists.ozlabs.org (Postfix) with ESMTP id 4DW8KR6GmDzDwyL for ; Thu, 4 Feb 2021 04:47:55 +1100 (AEDT) Received: from [192.168.0.104] (c-73-42-176-67.hsd1.wa.comcast.net [73.42.176.67]) by linux.microsoft.com (Postfix) with ESMTPSA id 60A2620B7192; Wed, 3 Feb 2021 09:47:54 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 60A2620B7192 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1612374474; bh=ccdnldXd7ffStD/bkTdf0JjvxcE1PixsU1LgmFGE+AQ=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=ajqWrUw9CR8dAwPmXY6LCKNUEia6bR5EjopHsReroJkEk/G8oj/LNYo6yVlhZHRPT gifIXM2rLnviz18/bU47RYoODn6g6eAz/ehhd+XdLDkL4/Db9ETaET7WsCMd4Jm0IR qbpqJGZRQppoEWCB6hHj8+tqyW4Ca58BYHrUL/GM= Subject: Re: [PATCH 1/2] ima: Free IMA measurement buffer on error To: Thiago Jung Bauermann References: <20210121173003.18324-1-nramas@linux.microsoft.com> <87eeic1u6b.fsf@manicouagan.localdomain> From: Lakshmi Ramasubramanian Message-ID: <918ff442-2a0d-0e5b-4e95-c47dafc11382@linux.microsoft.com> Date: Wed, 3 Feb 2021 09:47:53 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <87eeic1u6b.fsf@manicouagan.localdomain> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: sashal@kernel.org, dmitry.kasatkin@gmail.com, linux-kernel@vger.kernel.org, zohar@linux.ibm.com, tyhicks@linux.microsoft.com, ebiederm@xmission.com, gregkh@linuxfoundation.org, linux-integrity@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 1/22/21 2:30 PM, Thiago Jung Bauermann wrote: > > Hi Lakshmi, > > Lakshmi Ramasubramanian writes: > >> IMA allocates kernel virtual memory to carry forward the measurement >> list, from the current kernel to the next kernel on kexec system call, >> in ima_add_kexec_buffer() function. In error code paths this memory >> is not freed resulting in memory leak. >> >> Free the memory allocated for the IMA measurement list in >> the error code paths in ima_add_kexec_buffer() function. >> >> Signed-off-by: Lakshmi Ramasubramanian >> Suggested-by: Tyler Hicks >> Fixes: 7b8589cc29e7 ("ima: on soft reboot, save the measurement list") >> --- >> security/integrity/ima/ima_kexec.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c >> index 121de3e04af2..212145008a01 100644 >> --- a/security/integrity/ima/ima_kexec.c >> +++ b/security/integrity/ima/ima_kexec.c >> @@ -119,12 +119,14 @@ void ima_add_kexec_buffer(struct kimage *image) >> ret = kexec_add_buffer(&kbuf); >> if (ret) { >> pr_err("Error passing over kexec measurement buffer.\n"); >> + vfree(kexec_buffer); >> return; >> } > > This is a good catch. Thanks. > >> >> ret = arch_ima_add_kexec_buffer(image, kbuf.mem, kexec_segment_size); >> if (ret) { >> pr_err("Error passing over kexec measurement buffer.\n"); >> + vfree(kexec_buffer); >> return; >> } > > But this would cause problems, because the buffer is still there in the > kimage and would cause kimage_load_segment() to access invalid memory. > > There's no function to undo a kexec_add_buffer() to avoid this problem, > so I'd suggest just accepting the leak in this case. Fortunately, the > current implementations of arch_ima_add_kexec_buffer() are very simple > and cannot fail, so this is a theoretical problem. > Agreed. I'll post a new patch with the above change removed. thanks, -lakshmi