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 C31CDECAAA2 for ; Fri, 26 Aug 2022 00:26:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235785AbiHZA0u (ORCPT ); Thu, 25 Aug 2022 20:26:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35964 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229462AbiHZA0t (ORCPT ); Thu, 25 Aug 2022 20:26:49 -0400 Received: from mail-pj1-f42.google.com (mail-pj1-f42.google.com [209.85.216.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 09905AF4A6 for ; Thu, 25 Aug 2022 17:26:48 -0700 (PDT) Received: by mail-pj1-f42.google.com with SMTP id w88-20020a17090a6be100b001fbb0f0b013so507pjj.5 for ; Thu, 25 Aug 2022 17:26:48 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc; bh=BXo4LRgKgVTKWW02LRd5WxOgeTQRVas0PwL93Ve9P2Q=; b=OL2SQyFXFOBIn061ogYY2fNCZuR74LY5aZ3FItql4SkJcymlIDCuhZwVCi3hGWXyJD fCm4BDdNoK9FFrQTlUR+gnoIIDOQ86K2viHVzaarwLHX3KbkuWFUSwDmK0tGPBAl25wL 6qei4bSu6X3jWFSzQpOrbrrEoc0zz56w7T3b+T24ISL9I0vhNgkKubs6Ss9U84Wn7inL MY8FMVGoUdvvRoQ2tiKFAEyrAr6QsyFI4QyVRBdVRYuA8QdQ3UE4dssxoNRDvMH+wbVl d/cXbAA4o088RQnt5/ZcG0gUJyz5cIMhO485AZP8AR4ylAveZqvQKnqyeBmt7LlkJKSG 5Nvw== X-Gm-Message-State: ACgBeo2yyVvspBUrfDFNUsGgbVDVuTGwzoc4AEBxfDW9RTJC9TW9ShPT l8gno3Tj6/oEz5p5xh1HR/0= X-Google-Smtp-Source: AA6agR6WQrtcypajHdQHMVkGIFBWfeCbJCs7StyxP6fKJMx5miYEHfMp9ZCjGR7OaWd0+XmJuV7qnQ== X-Received: by 2002:a17:902:ef4f:b0:173:353:3f6c with SMTP id e15-20020a170902ef4f00b0017303533f6cmr1502882plx.6.1661473607441; Thu, 25 Aug 2022 17:26:47 -0700 (PDT) Received: from bvanassche-linux.mtv.corp.google.com ([2620:15c:211:201:349c:3078:d005:5a7e]) by smtp.gmail.com with ESMTPSA id a14-20020a170902710e00b0016d150c6c6dsm172319pll.45.2022.08.25.17.26.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Aug 2022 17:26:46 -0700 (PDT) From: Bart Van Assche To: "Martin K . Petersen" Cc: linux-scsi@vger.kernel.org, Bart Van Assche , Ming Lei , Christoph Hellwig , Mike Christie , Hannes Reinecke , John Garry , Li Zhijian , "James E.J. Bottomley" Subject: [PATCH] scsi: core: Fix a use-after-free Date: Thu, 25 Aug 2022 17:26:34 -0700 Message-Id: <20220826002635.919423-1-bvanassche@acm.org> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org There are two .exit_cmd_priv implementations. Both implementations use resources associated with the SCSI host. Make sure that these resources are still available when .exit_cmd_priv is called by waiting inside scsi_remove_host() until the tag set has been freed. This patch fixes the following use-after-free: ================================================================== BUG: KASAN: use-after-free in srp_exit_cmd_priv+0x27/0xd0 [ib_srp] Read of size 8 at addr ffff888100337000 by task multipathd/16727 Call Trace: dump_stack_lvl+0x34/0x44 print_report.cold+0x5e/0x5db kasan_report+0xab/0x120 srp_exit_cmd_priv+0x27/0xd0 [ib_srp] scsi_mq_exit_request+0x4d/0x70 blk_mq_free_rqs+0x143/0x410 __blk_mq_free_map_and_rqs+0x6e/0x100 blk_mq_free_tag_set+0x2b/0x160 scsi_host_dev_release+0xf3/0x1a0 device_release+0x54/0xe0 kobject_put+0xa5/0x120 device_release+0x54/0xe0 kobject_put+0xa5/0x120 scsi_device_dev_release_usercontext+0x4c1/0x4e0 execute_in_process_context+0x23/0x90 device_release+0x54/0xe0 kobject_put+0xa5/0x120 scsi_disk_release+0x3f/0x50 device_release+0x54/0xe0 kobject_put+0xa5/0x120 disk_release+0x17f/0x1b0 device_release+0x54/0xe0 kobject_put+0xa5/0x120 dm_put_table_device+0xa3/0x160 [dm_mod] dm_put_device+0xd0/0x140 [dm_mod] free_priority_group+0xd8/0x110 [dm_multipath] free_multipath+0x94/0xe0 [dm_multipath] dm_table_destroy+0xa2/0x1e0 [dm_mod] __dm_destroy+0x196/0x350 [dm_mod] dev_remove+0x10c/0x160 [dm_mod] ctl_ioctl+0x2c2/0x590 [dm_mod] dm_ctl_ioctl+0x5/0x10 [dm_mod] __x64_sys_ioctl+0xb4/0xf0 dm_ctl_ioctl+0x5/0x10 [dm_mod] __x64_sys_ioctl+0xb4/0xf0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Cc: Ming Lei Cc: Christoph Hellwig Cc: Mike Christie Cc: Hannes Reinecke Cc: John Garry Cc: Li Zhijian Reported-by: Li Zhijian Fixes: 65ca846a5314 ("scsi: core: Introduce {init,exit}_cmd_priv()") Signed-off-by: Bart Van Assche --- drivers/scsi/hosts.c | 16 +++++++++++++--- drivers/scsi/scsi_lib.c | 6 +++++- drivers/scsi/scsi_priv.h | 2 +- drivers/scsi/scsi_scan.c | 1 + drivers/scsi/scsi_sysfs.c | 1 + include/scsi/scsi_host.h | 2 ++ 6 files changed, 23 insertions(+), 5 deletions(-) diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index 26bf3b153595..9857dba09c95 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -182,6 +182,15 @@ void scsi_remove_host(struct Scsi_Host *shost) mutex_unlock(&shost->scan_mutex); scsi_proc_host_rm(shost); + /* + * New SCSI devices cannot be attached anymore because of the SCSI host + * state so drop the tag set refcnt. Wait until the tag set refcnt drops + * to zero because .exit_cmd_priv implementations may need the host + * pointer. + */ + kref_put(&shost->tagset_refcnt, scsi_mq_free_tags); + wait_for_completion(&shost->tagset_freed); + spin_lock_irqsave(shost->host_lock, flags); if (scsi_host_set_state(shost, SHOST_DEL)) BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY)); @@ -245,6 +254,9 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev, if (error) goto fail; + kref_init(&shost->tagset_refcnt); + init_completion(&shost->tagset_freed); + /* * Increase usage count temporarily here so that calling * scsi_autopm_put_host() will trigger runtime idle if there is @@ -317,6 +329,7 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev, pm_runtime_disable(&shost->shost_gendev); pm_runtime_set_suspended(&shost->shost_gendev); pm_runtime_put_noidle(&shost->shost_gendev); + kref_put(&shost->tagset_refcnt, scsi_mq_free_tags); fail: return error; } @@ -350,9 +363,6 @@ static void scsi_host_dev_release(struct device *dev) kfree(dev_name(&shost->shost_dev)); } - if (shost->tag_set.tags) - scsi_mq_destroy_tags(shost); - kfree(shost->shost_data); ida_free(&host_index_ida, shost->host_no); diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 4dbd29ab1dcc..1f30e0c54e55 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1976,9 +1976,13 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost) return blk_mq_alloc_tag_set(tag_set); } -void scsi_mq_destroy_tags(struct Scsi_Host *shost) +void scsi_mq_free_tags(struct kref *kref) { + struct Scsi_Host *shost = container_of(kref, typeof(*shost), + tagset_refcnt); + blk_mq_free_tag_set(&shost->tag_set); + complete(&shost->tagset_freed); } /** diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h index 429663bd78ec..f385b3f04d6e 100644 --- a/drivers/scsi/scsi_priv.h +++ b/drivers/scsi/scsi_priv.h @@ -94,7 +94,7 @@ extern void scsi_run_host_queues(struct Scsi_Host *shost); extern void scsi_requeue_run_queue(struct work_struct *work); extern void scsi_start_queue(struct scsi_device *sdev); extern int scsi_mq_setup_tags(struct Scsi_Host *shost); -extern void scsi_mq_destroy_tags(struct Scsi_Host *shost); +extern void scsi_mq_free_tags(struct kref *kref); extern void scsi_exit_queue(void); extern void scsi_evt_thread(struct work_struct *work); diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c index 91ac901a6682..5d27f5196de6 100644 --- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -340,6 +340,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget, kfree(sdev); goto out; } + kref_get(&sdev->host->tagset_refcnt); sdev->request_queue = q; q->queuedata = sdev; __scsi_init_queue(sdev->host, q); diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index aa70d9282161..5d61f58399dc 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -1476,6 +1476,7 @@ void __scsi_remove_device(struct scsi_device *sdev) mutex_unlock(&sdev->state_mutex); blk_mq_destroy_queue(sdev->request_queue); + kref_put(&sdev->host->tagset_refcnt, scsi_mq_free_tags); cancel_work_sync(&sdev->requeue_work); if (sdev->host->hostt->slave_destroy) diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index b6e41ee3d566..9b0a028bf053 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -557,6 +557,8 @@ struct Scsi_Host { struct scsi_host_template *hostt; struct scsi_transport_template *transportt; + struct kref tagset_refcnt; + struct completion tagset_freed; /* Area to keep a shared tag map */ struct blk_mq_tag_set tag_set;