From patchwork Mon Feb 13 03:43:21 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhong Jinghua X-Patchwork-Id: 653429 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 109B2C05027 for ; Mon, 13 Feb 2023 03:19:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229719AbjBMDTo (ORCPT ); Sun, 12 Feb 2023 22:19:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39558 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229468AbjBMDTn (ORCPT ); Sun, 12 Feb 2023 22:19:43 -0500 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AA0C79EFC; Sun, 12 Feb 2023 19:19:42 -0800 (PST) Received: from mail02.huawei.com (unknown [172.30.67.143]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4PFV216Ngcz4f3m7B; Mon, 13 Feb 2023 11:19:37 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.127.227]) by APP3 (Coremail) with SMTP id _Ch0CgBH9CFKrOljm6DaDA--.29473S4; Mon, 13 Feb 2023 11:19:39 +0800 (CST) From: Zhong Jinghua To: jejb@linux.ibm.com, martin.petersen@oracle.com Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, zhongjinghua@huawei.com, yi.zhang@huawei.com, yukuai3@huawei.com Subject: [PATCH-next] scsi: fix use-after-free problem in scsi_remove_target Date: Mon, 13 Feb 2023 11:43:21 +0800 Message-Id: <20230213034321.3261114-1-zhongjinghua@huaweicloud.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 X-CM-TRANSID: _Ch0CgBH9CFKrOljm6DaDA--.29473S4 X-Coremail-Antispam: 1UD129KBjvJXoW7WFW8Gw4UCFy7tw1Utr1DKFg_yoW5JF1fpF WrG34Y9r4UG39Y9ws5XF4rXFy5Aa1agry5uFyxW3WfXa45J34avw1SkF9ruas0yFWqga4U GF4kAF18tF4DCrJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUgCb4IE77IF4wAFF20E14v26r4j6ryUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6r1S6rWUM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4 vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7Cj xVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x 0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG 6I80ewAv7VC0I7IYx2IY67AKxVWUtVWrXwAv7VC2z280aVAFwI0_Gr0_Cr1lOx8S6xCaFV Cjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JMxAIw28IcxkI7VAKI48JMxC20s026xCaFVCj c4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4 CE17CEb7AF67AKxVWUAVWUtwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1x MIIF0xvE2Ix0cI8IcVCY1x0267AKxVWUJVW8JwCI42IY6xAIw20EY4v20xvaj40_Zr0_Wr 1UMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Jr0_GrUvcSsG vfC2KfnxnUUI43ZEXa7IU8UfHUUUUUU== X-CM-SenderInfo: x2kr0wpmlqwxtxd6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org From: Zhong Jinghua A use-after-free problem like below: BUG: KASAN: use-after-free in scsi_target_reap+0x6c/0x70 Workqueue: scsi_wq_1 __iscsi_unbind_session [scsi_transport_iscsi] Call trace: dump_backtrace+0x0/0x320 show_stack+0x24/0x30 dump_stack+0xdc/0x128 print_address_description+0x68/0x278 kasan_report+0x1e4/0x308 __asan_report_load4_noabort+0x30/0x40 scsi_target_reap+0x6c/0x70 scsi_remove_target+0x430/0x640 __iscsi_unbind_session+0x164/0x268 [scsi_transport_iscsi] process_one_work+0x67c/0x1350 worker_thread+0x370/0xf90 kthread+0x2a4/0x320 ret_from_fork+0x10/0x18 The problem is caused by a concurrency scenario: T0: delete target // echo 1 > /sys/devices/platform/host1/session1/target1:0:0/1:0:0:1/delete T1: logout // iscsiadm -m node --logout T0 T1 sdev_store_delete scsi_remove_device device_remove_file __scsi_remove_device __iscsi_unbind_session scsi_remove_target spin_lock_irqsave list_for_each_entry scsi_target_reap // starget->reaf 1 -> 0 kref_get(&starget->reap_ref); // warn use-after-free. spin_unlock_irqrestore scsi_target_reap_ref_release scsi_target_destroy ... // delete starget scsi_target_reap // UAF When T0 reduces the reference count to 0, but has not been released, T1 can still enter list_for_each_entry, and then kref_get reports UAF. Fix it by using kref_get_unless_zero() to check for a reference count of 0. Signed-off-by: Zhong Jinghua --- drivers/scsi/scsi_sysfs.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index e7893835b99a..0ad357ff4c59 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -1561,7 +1561,17 @@ void scsi_remove_target(struct device *dev) starget->state == STARGET_CREATED_REMOVE) continue; if (starget->dev.parent == dev || &starget->dev == dev) { - kref_get(&starget->reap_ref); + + /* + * If starget->reap_ref is reduced to 0, it means + * that other processes are releasing it and + * there is no need to delete it again + */ + if (!kref_get_unless_zero(&starget->reap_ref)) { + spin_unlock_irqrestore(shost->host_lock, flags); + goto restart; + } + if (starget->state == STARGET_CREATED) starget->state = STARGET_CREATED_REMOVE; else