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 F3BBEC43334 for ; Thu, 23 Jun 2022 10:47:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231138AbiFWKr2 (ORCPT ); Thu, 23 Jun 2022 06:47:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43586 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230487AbiFWKr0 (ORCPT ); Thu, 23 Jun 2022 06:47:26 -0400 Received: from mail-pj1-x1044.google.com (mail-pj1-x1044.google.com [IPv6:2607:f8b0:4864:20::1044]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 335A34B1EB; Thu, 23 Jun 2022 03:47:23 -0700 (PDT) Received: by mail-pj1-x1044.google.com with SMTP id i8-20020a17090aee8800b001ecc929d14dso3430855pjz.0; Thu, 23 Jun 2022 03:47:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=FyEUu15vvzH95LcwuWkWyhW3ebF5SK1T267BEuaWV3g=; b=KESis4YxduSsCemtNPXlOa0SV4p4nwujQpil/zxARLDUiXNMcSc44QiCNu6hvEmVNh aTlLI+uQBCqDhWoDUiDkp0HZLnH9SWcpJiPo9I8zpHdFm0lf8u79kuBUjOx8y0Snq5/V KUJcbdhlMlEgpKyYjqyfoaPOND5flIPf60vEDIgMGwTWUh5IRqLOYornvqVtpjvCBWZb uPYKbN8WLbyR2HaPM1JZ0WxMeKt7mloeOXYusMdKSBT3xmwBcCImkDEW2jKMKFPFjzOh g94xvEt67d1H+Md6uUyW8PPBma9s1A8yDlugoVZSbxVWRvmQVsPJmqUhenL1kGTOL20C Np9Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=FyEUu15vvzH95LcwuWkWyhW3ebF5SK1T267BEuaWV3g=; b=WkdG1MEuSk4FURDxfVElVd0ueEhsZUqCGbT9xOVFPEMO8S/UQ17voaL82mJEgrd37U AqUb7lBCU5D5wx6/rbPKHBMZcL21t8Ru5mrkf9O7/OkG7vDDgLIEYyh9v1xbeN6pAcvx qM5P8eCMFWzzR84JqxhpHwIQ9/3FD5I7aDBC0st/yWPSngCDX7fmiTYuPJipbrgmvdMP CGM4ODHprmZlqsr2/kUY8O6w1VDRf0Yqz/oy/9BgdjKG8t57kYyPB6RM4gUS+3Sw+fWF COA93sCoJ7+QBleFUuEE8mA+cqrjyhpqlYL1OB+LK+CM/y8ea+FneALF8MLyFqRJWNyl jhew== X-Gm-Message-State: AJIora8sGRapu9ICZbrGZmI3+dtKxtQDKnfgbOBiOyUJ8eq8RFBOCeFm UZzN6ar56Bice75KMRH1was= X-Google-Smtp-Source: AGRyM1s4qcoH9Z6XWD2ITvm7Hnwb7mNlMppHGiV2QsaEIPLGPPJ+TN3hRoaWL7F/we0gctdiA/NZMg== X-Received: by 2002:a17:902:ea4b:b0:168:d5e9:68ec with SMTP id r11-20020a170902ea4b00b00168d5e968ecmr38343340plg.146.1655981243389; Thu, 23 Jun 2022 03:47:23 -0700 (PDT) Received: from [192.168.50.247] ([103.84.139.165]) by smtp.gmail.com with ESMTPSA id f25-20020a637559000000b0040cf934a1a0sm5384193pgn.28.2022.06.23.03.47.21 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 23 Jun 2022 03:47:23 -0700 (PDT) Message-ID: <31fa8ce4-a132-03c6-3272-6f8448270830@gmail.com> Date: Thu, 23 Jun 2022 18:47:19 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH] nfc: st21nfca: fix possible double free in st21nfca_im_recv_dep_res_cb() Content-Language: en-US To: Paolo Abeni , krzysztof.kozlowski@linaro.org, sameo@linux.intel.com, christophe.ricard@gmail.com Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20220622065117.23210-1-hbh25y@gmail.com> <39279ba0ced207f484b664fe5364fa4ee6271cfb.camel@redhat.com> From: Hangyu Hua In-Reply-To: <39279ba0ced207f484b664fe5364fa4ee6271cfb.camel@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/6/23 17:42, Paolo Abeni wrote: > On Wed, 2022-06-22 at 14:51 +0800, Hangyu Hua wrote: >> nfc_tm_data_received will free skb internally when it fails. There is no >> need to free skb in st21nfca_im_recv_dep_res_cb again. >> >> Fix this by setting skb to NULL when nfc_tm_data_received fails. >> >> Fixes: 1892bf844ea0 ("NFC: st21nfca: Adding P2P support to st21nfca in Initiator & Target mode") >> Signed-off-by: Hangyu Hua >> --- >> drivers/nfc/st21nfca/dep.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/nfc/st21nfca/dep.c b/drivers/nfc/st21nfca/dep.c >> index 1ec651e31064..07ac5688011c 100644 >> --- a/drivers/nfc/st21nfca/dep.c >> +++ b/drivers/nfc/st21nfca/dep.c >> @@ -594,7 +594,8 @@ static void st21nfca_im_recv_dep_res_cb(void *context, struct sk_buff *skb, >> ST21NFCA_NFC_DEP_PFB_PNI(dep_res->pfb + 1); >> size++; >> skb_pull(skb, size); >> - nfc_tm_data_received(info->hdev->ndev, skb); >> + if (nfc_tm_data_received(info->hdev->ndev, skb)) >> + skb = NULL; > > Note that 'skb' not used (nor freed) by this function after this point: > the next 'break' statement refears to the inner switch, and land to the > execution flow to the 'return' statement a few lines below. > kfree_skb(skb) is never reached. > > Paolo > My fault. I messed up two switch statements. I will be more careful next time. hangyu