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 7F8CEC433EF for ; Thu, 14 Apr 2022 05:32:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239900AbiDNFeZ (ORCPT ); Thu, 14 Apr 2022 01:34:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43990 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239862AbiDNFeK (ORCPT ); Thu, 14 Apr 2022 01:34:10 -0400 Received: from zju.edu.cn (mail.zju.edu.cn [61.164.42.155]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1807A3B3FC; Wed, 13 Apr 2022 22:31:42 -0700 (PDT) Received: from ubuntu.localdomain (unknown [10.15.192.164]) by mail-app4 (Coremail) with SMTP id cS_KCgDHr_KqsVdi+oM1AQ--.59165S3; Thu, 14 Apr 2022 13:31:32 +0800 (CST) From: Duoming Zhou To: krzk@kernel.org, linux-kernel@vger.kernel.org Cc: davem@davemloft.net, gregkh@linuxfoundation.org, alexander.deucher@amd.com, akpm@linux-foundation.org, broonie@kernel.org, netdev@vger.kernel.org, linma@zju.edu.cn, Duoming Zhou Subject: [PATCH V3 1/3] drivers: nfc: nfcmrvl: fix double free bugs caused by fw_dnld_over() Date: Thu, 14 Apr 2022 13:31:20 +0800 Message-Id: <1d34425a0ea8a553a66dcf4f22ca55cc920dbb42.1649913521.git.duoming@zju.edu.cn> X-Mailer: git-send-email 2.17.1 In-Reply-To: References: In-Reply-To: References: X-CM-TRANSID: cS_KCgDHr_KqsVdi+oM1AQ--.59165S3 X-Coremail-Antispam: 1UD129KBjvJXoWxWr47uw4DAry7uw1DGFW5trb_yoWrAF17pF 45WFykJr1qkr4YgF98ta1DAF98Aw43CrWUGF98Ja4xZrn0yF1vyw1ktay5ZrsFgr4Dta13 GasxJa4UCFsYyr7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUvm1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s1l1IIY67AE w4v_Jr0_Jr4l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2 IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVWxJr0_GcWl84ACjcxK6I8E 87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s1le2I262IYc4CY6c 8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jr0_ Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwI xGrwACjI8F5VA0II8E6IAqYI8I648v4I1lFIxGxcIEc7CjxVA2Y2ka0xkIwI1l42xK82IY c2Ij64vIr41l42xK82IY6x8ErcxFaVAv8VW8uw4UJr1UMxC20s026xCaFVCjc4AY6r1j6r 4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF 67AKxVWUtVW8ZwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2I x0cI8IcVCY1x0267AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2 z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnU UI43ZEXa7VUbXdbUUUUUU== X-CM-SenderInfo: qssqjiasttq6lmxovvfxof0/1tbiAgITAVZdtZLd3gAesj Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There are potential double free bugs in nfcmrvl usb driver among fw_dnld_rx_work(), fw_dnld_timeout() and nfcmrvl_nci_unregister_dev(). All these three functions will call fw_dnld_over(). The fw_dnld_rx_work() is a work item, the fw_dnld_timeout() is a timer handler and the nfcmrvl_nci_unregister_dev() is called when nfcmrvl_nci device is detaching. So these three functions could execute concurrently. The race between fw_dnld_rx_work() and nfcmrvl_nci_unregister_dev() can be shown as below: (Thread 1) | (Thread 2) | fw_dnld_rx_work | fw_dnld_over | release_firmware | kfree(fw); //(1) nfcmrvl_disconnect | nfcmrvl_nci_unregister_dev | nfcmrvl_fw_dnld_abort | fw_dnld_over | ... if (priv->fw_dnld.fw) | release_firmware | kfree(fw); //(2) | ... | priv->fw_dnld.fw = NULL; When the fw_dnld_rx_work work item is executing, we detach the device. The release_firmware() will deallocate firmware in position (1), but firmware will be deallocated again in position (2), which leads to double free. The race between fw_dnld_rx_work() and fw_dnld_timeout() can be shown as below: (Thread 1) | (Thread 2) | fw_dnld_rx_work | fw_dnld_over | release_firmware | kfree(fw); //(1) fw_dnld_timeout | fw_dnld_over | ... if (priv->fw_dnld.fw) | release_firmware | kfree(fw); //(2) | ... | priv->fw_dnld.fw = NULL; The release_firmware() will deallocate firmware in position (1), but firmware will be deallocated again in position (2), which leads to double free. The race between fw_dnld_timeout() and nfcmrvl_nci_unregister_dev() can be shown as below. (Thread 1) | (Thread 2) | nfcmrvl_disconnect | nfcmrvl_nci_unregister_dev | nfcmrvl_fw_dnld_abort | fw_dnld_over | release_firmware | kfree(fw); //(1) fw_dnld_timeout | fw_dnld_over | ... if (priv->fw_dnld.fw) | release_firmware | kfree(fw); //(2) | ... | priv->fw_dnld.fw = NULL; The release_firmware() will deallocate firmware in position (1), but firmware will be deallocated again in position (2), which leads to double free. This patch adds spin_lock_irq in fw_dnld_over() in order to synchronize among different threads that call fw_dnld_over(). The priv->fw_dnld.fw will be set to NULL after work item is finished and fw_dnld_over() called by other threads will check whether priv->fw_dnld.fw is NULL. So the double free bug could be prevented. Fixes: 3194c6870158e3 ("NFC: nfcmrvl: add firmware download support") Signed-off-by: Duoming Zhou Reviewed-by: Lin Ma --- Changes in V3: - Make commit message more clearer. - Use spin_lock_irq to synchronize. drivers/nfc/nfcmrvl/fw_dnld.c | 3 +++ drivers/nfc/nfcmrvl/fw_dnld.h | 2 ++ 2 files changed, 5 insertions(+) diff --git a/drivers/nfc/nfcmrvl/fw_dnld.c b/drivers/nfc/nfcmrvl/fw_dnld.c index e83f65596a8..c22a4556db5 100644 --- a/drivers/nfc/nfcmrvl/fw_dnld.c +++ b/drivers/nfc/nfcmrvl/fw_dnld.c @@ -92,12 +92,14 @@ static struct sk_buff *alloc_lc_skb(struct nfcmrvl_private *priv, uint8_t plen) static void fw_dnld_over(struct nfcmrvl_private *priv, u32 error) { + spin_lock_irq(&priv->fw_dnld.lock); if (priv->fw_dnld.fw) { release_firmware(priv->fw_dnld.fw); priv->fw_dnld.fw = NULL; priv->fw_dnld.header = NULL; priv->fw_dnld.binary_config = NULL; } + spin_unlock_irq(&priv->fw_dnld.lock); atomic_set(&priv->ndev->cmd_cnt, 0); @@ -451,6 +453,7 @@ int nfcmrvl_fw_dnld_init(struct nfcmrvl_private *priv) if (!priv->fw_dnld.rx_wq) return -ENOMEM; skb_queue_head_init(&priv->fw_dnld.rx_q); + spin_lock_init(&priv->fw_dnld.lock); return 0; } diff --git a/drivers/nfc/nfcmrvl/fw_dnld.h b/drivers/nfc/nfcmrvl/fw_dnld.h index 7c4d91b0191..6974c307947 100644 --- a/drivers/nfc/nfcmrvl/fw_dnld.h +++ b/drivers/nfc/nfcmrvl/fw_dnld.h @@ -75,6 +75,8 @@ struct nfcmrvl_fw_dnld { struct sk_buff_head rx_q; struct timer_list timer; + /* To synchronize among different threads that call firmware.*/ + spinlock_t lock; }; int nfcmrvl_fw_dnld_init(struct nfcmrvl_private *priv); -- 2.17.1