From nobody Wed Dec 17 21:13:32 2025 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 BDB7AC77B76 for ; Mon, 17 Apr 2023 16:53:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229878AbjDQQxQ (ORCPT ); Mon, 17 Apr 2023 12:53:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60948 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229485AbjDQQxO (ORCPT ); Mon, 17 Apr 2023 12:53:14 -0400 Received: from m12.mail.163.com (m12.mail.163.com [220.181.12.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id F3AE78F for ; Mon, 17 Apr 2023 09:53:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=difeq NYROJLd3h7pJgHbiQGat6ELIM7KbJhDgj4H5js=; b=EKu60oX0w16R8PltMmtIK YbgiRhHMdG4GiNpUM7mRAczlD4wCqyYmHmZIXqLOWM5uA7KHL4B3DhyVBYCdAoZ1 C4Mw5/aaysBCenWZS+JM+vH2uySewzwG75X4YY34rwpPtD2NbXZsTwFBo6vaTriU X3Fxhx+h4aFERFCkZv37Lg= Received: from leanderwang-LC2.localdomain (unknown [111.206.145.21]) by zwqz-smtp-mta-g3-3 (Coremail) with SMTP id _____wB33mZgeT1kpY0GBw--.48629S2; Tue, 18 Apr 2023 00:52:48 +0800 (CST) From: Zheng Wang To: matt.hsiao@hpe.com Cc: arnd@arndb.de, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, hackerzheng666@gmail.com, 1395428693sheep@gmail.com, alex000young@gmail.com, Zheng Wang Subject: [PATCH] misc: hpilo: Fix use after free bug in ilo_remove due to race condition with ilo_open Date: Tue, 18 Apr 2023 00:52:46 +0800 Message-Id: <20230417165246.467723-1-zyytlz.wz@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wB33mZgeT1kpY0GBw--.48629S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxGryUJFyDuFWDKFyxZr4kXrb_yoW5Ww1xpF W5Xa45CF4rXrZrWF4Utr4DCFyay34xtrykGrWIk3s5ZF1Svr1vgF18ta4UZFy5tFZ5XF13 JF1YgryrG3WUJaUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0ziaiiDUUUUU= X-Originating-IP: [111.206.145.21] X-CM-SenderInfo: h2113zf2oz6qqrwthudrp/1tbiXAFUU1Xl6SOPWAAAs3 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" A race condition may occur if the user physically removes the ilo device=20 while calling ilo_open. If we remove the driver which will call ilo_remove to make cleanup, there=20 is no guarantee to make sure there's no more ilo_open invoking. The possible sequence is as follows: Fix it by adding a refcount check to ilo_remove() function to free the=20 "ilo_hwinfo " structure after the last file is closed. CPU0 CPU1 |ilo_open ilo_remove | kfree(ilo_hw) | //free | |hw =3D container_of(ip->i_cdev, |struct ilo_hwinfo, cdev); |hw->ccb_alloc[slot] |//use Fixes: 89bcb05d9bbf ("HP iLO driver") Signed-off-by: Zheng Wang --- drivers/misc/hpilo.c | 16 +++++++++++++++- drivers/misc/hpilo.h | 1 + 2 files changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/misc/hpilo.c b/drivers/misc/hpilo.c index 8d00df9243c4..2e9af39e91a4 100644 --- a/drivers/misc/hpilo.c +++ b/drivers/misc/hpilo.c @@ -37,6 +37,8 @@ static const struct pci_device_id ilo_blacklist[] =3D { {} }; =20 +static void ilo_delete(struct kref *kref); + static inline int get_entry_id(int entry) { return (entry & ENTRY_MASK_DESCRIPTOR) >> ENTRY_BITPOS_DESCRIPTOR; @@ -559,6 +561,7 @@ static int ilo_close(struct inode *ip, struct file *fp) hw->ccb_alloc[slot]->ccb_cnt--; =20 spin_unlock(&hw->open_lock); + kref_put(&hw->refcnt, ilo_delete); =20 return 0; } @@ -578,6 +581,7 @@ static int ilo_open(struct inode *ip, struct file *fp) if (!data) return -ENOMEM; =20 + kref_get(&hw->refcnt); spin_lock(&hw->open_lock); =20 /* each fd private_data holds sw/hw view of ccb */ @@ -633,6 +637,8 @@ static int ilo_open(struct inode *ip, struct file *fp) =20 if (!error) fp->private_data =3D hw->ccb_alloc[slot]; + else + kref_put(&hw->refcnt, ilo_delete); =20 return error; } @@ -742,8 +748,15 @@ static int ilo_map_device(struct pci_dev *pdev, struct= ilo_hwinfo *hw) =20 static void ilo_remove(struct pci_dev *pdev) { - int i, minor; struct ilo_hwinfo *ilo_hw =3D pci_get_drvdata(pdev); + kref_put(&ilo_hw->refcnt, ilo_delete); +} + +static void ilo_delete(struct kref *kref) +{ + int i, minor; + struct ilo_hwinfo *ilo_hw =3D container_of(kref, struct ilo_hwinfo, refcn= t); + struct pci_dev *pdev =3D ilo_hw->ilo_dev; =20 if (!ilo_hw) return; @@ -807,6 +820,7 @@ static int ilo_probe(struct pci_dev *pdev, goto out; =20 ilo_hw->ilo_dev =3D pdev; + kref_init(&ilo_hw->refcnt); spin_lock_init(&ilo_hw->alloc_lock); spin_lock_init(&ilo_hw->fifo_lock); spin_lock_init(&ilo_hw->open_lock); diff --git a/drivers/misc/hpilo.h b/drivers/misc/hpilo.h index d57c34680b09..ebc677eb45ae 100644 --- a/drivers/misc/hpilo.h +++ b/drivers/misc/hpilo.h @@ -62,6 +62,7 @@ struct ilo_hwinfo { spinlock_t fifo_lock; =20 struct cdev cdev; + struct kref refcnt; }; =20 /* offset from mmio_vaddr for enabling doorbell interrupts */ --=20 2.25.1