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 9EE86C433EF for ; Thu, 26 May 2022 15:45:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343617AbiEZPph (ORCPT ); Thu, 26 May 2022 11:45:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49628 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232621AbiEZPpd (ORCPT ); Thu, 26 May 2022 11:45:33 -0400 Received: from alexa-out.qualcomm.com (alexa-out.qualcomm.com [129.46.98.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 64AA6C6E77; Thu, 26 May 2022 08:45:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1653579932; x=1685115932; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=CkiHfK8/LMfUY/TQgcX12rRTrkAq3XCsa8+R5XT6JNY=; b=AJKzQs/UA0hiqydUfEBRu16IRiw+gKKOyKicS1tFUKvMbqhQ3uJRHxOZ NCmd2sEpQx8ePqxpRr1ZkbYxLCTbo5VA9MXiHYtuJR+J98hmid/1zaxYh PTCHiUzR6ethF7SFyknaZkSBtgXUHaEHCWxCiyUsOHVtPA6zVFF+71ja3 o=; Received: from ironmsg-lv-alpha.qualcomm.com ([10.47.202.13]) by alexa-out.qualcomm.com with ESMTP; 26 May 2022 08:45:32 -0700 X-QCInternal: smtphost Received: from nasanex01c.na.qualcomm.com ([10.47.97.222]) by ironmsg-lv-alpha.qualcomm.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 May 2022 08:45:31 -0700 Received: from nalasex01a.na.qualcomm.com (10.47.209.196) by nasanex01c.na.qualcomm.com (10.47.97.222) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.22; Thu, 26 May 2022 08:45:31 -0700 Received: from [10.110.93.98] (10.80.80.8) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.22; Thu, 26 May 2022 08:45:30 -0700 Message-ID: <25540c69-c58c-0dc5-29b3-4914a656a06f@quicinc.com> Date: Thu, 26 May 2022 08:45:29 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH] ath11k: mhi: fix potential memory leak in ath11k_mhi_register() Content-Language: en-US To: Jianglei Nie , , , , , CC: , , , References: <20220526100227.483609-1-niejianglei2021@163.com> From: Jeff Johnson In-Reply-To: <20220526100227.483609-1-niejianglei2021@163.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01a.na.qualcomm.com (10.47.209.196) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/26/2022 3:02 AM, Jianglei Nie wrote: > mhi_alloc_controller() allocates a memory space for mhi_ctrl. When some > errors occur, mhi_ctrl should be freed by mhi_free_controller(). But > when ath11k_mhi_read_addr_from_dt() fails, the function returns without > calling mhi_free_controller(), which will lead to a memory leak. > > We can fix it by calling mhi_free_controller() when > ath11k_mhi_read_addr_from_dt() fails. > > Signed-off-by: Jianglei Nie Reviewed-by: Jeff Johnson > --- > drivers/net/wireless/ath/ath11k/mhi.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/wireless/ath/ath11k/mhi.c b/drivers/net/wireless/ath/ath11k/mhi.c > index fc3524e83e52..3318c7c2b32b 100644 > --- a/drivers/net/wireless/ath/ath11k/mhi.c > +++ b/drivers/net/wireless/ath/ath11k/mhi.c > @@ -376,8 +376,10 @@ int ath11k_mhi_register(struct ath11k_pci *ab_pci) > > if (test_bit(ATH11K_FLAG_FIXED_MEM_RGN, &ab->dev_flags)) { > ret = ath11k_mhi_read_addr_from_dt(mhi_ctrl); > - if (ret < 0) > + if (ret < 0) { > + mhi_free_controller(mhi_ctrl); > return ret; > + } > } else { > mhi_ctrl->iova_start = 0; > mhi_ctrl->iova_stop = 0xFFFFFFFF; This patch looks good to me. However there is an additional issue that IMO should be addressed in this function with a separate patch. Just after mhi_ctrl is allocated the pointer is saved: ab_pci->mhi_ctrl = mhi_ctrl; When there is an error, mhi_ctrl is freed, but ab_pci->mhi_ctrl still has a dangling pointer to the freed memory. This has the potential to result in a subsequent use-after-free or double-free error. So IMO we should do one of two things (I haven't looked at the code in detail to determine which is better): 1) don't set ab_pci->mhi_ctrl = mhi_ctrl until the end of the function after success from mhi_register_controller(). This requires that none of the functions called between the current assignment point and the proposed assignment point dereference ab_pci->mhi_ctrl 2) set ab_pci->mhi_ctrl = NULL in all of the places where we call mhi_free_controller() 2a) have a central error exit label and have all of the error conditions goto that label where there is a central code: mhi_free_controller(mhi_ctrl); ab_pci->mhi_ctrl = NULL; return ret;