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 X-Spam-Level: X-Spam-Status: No, score=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2D51BC43219 for ; Fri, 24 Sep 2021 08:20:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1790961076 for ; Fri, 24 Sep 2021 08:20:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244681AbhIXIVT (ORCPT ); Fri, 24 Sep 2021 04:21:19 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:16380 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244677AbhIXIVQ (ORCPT ); Fri, 24 Sep 2021 04:21:16 -0400 Received: from dggemv704-chm.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4HG4bN11nDzRQGK; Fri, 24 Sep 2021 16:15:28 +0800 (CST) Received: from dggema762-chm.china.huawei.com (10.1.198.204) by dggemv704-chm.china.huawei.com (10.3.19.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2308.8; Fri, 24 Sep 2021 16:19:41 +0800 Received: from [10.174.176.73] (10.174.176.73) by dggema762-chm.china.huawei.com (10.1.198.204) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.8; Fri, 24 Sep 2021 16:19:40 +0800 Subject: Re: [PATCH 6/6] rq-qos: fix uaf in rq_qos_done_io() To: Ming Lei CC: , , , , , References: <20210923134631.105719-1-yukuai3@huawei.com> <20210923134631.105719-7-yukuai3@huawei.com> From: "yukuai (C)" Message-ID: Date: Fri, 24 Sep 2021 16:19:40 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="gbk"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.176.73] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggema762-chm.china.huawei.com (10.1.198.204) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 2021/09/24 9:49, Ming Lei wrote: > On Fri, Sep 24, 2021 at 09:23:42AM +0800, yukuai (C) wrote: >> On 2021/09/24 8:41, Ming Lei wrote: >>> On Thu, Sep 23, 2021 at 09:46:31PM +0800, Yu Kuai wrote: >>>> our test report a uaf: >>>> >>>> [ 142.925504] ================================================================== >>>> [ 142.929084] BUG: KASAN: use-after-free in __rq_qos_done_bio+0x57/0x90 >>>> [ 142.931131] Read of size 8 at addr ffff88810306d858 by task blkdiscard/858 >>>> [ 142.933289] >>>> [ 142.933798] CPU: 1 PID: 858 Comm: blkdiscard Not tainted 5.15.0-rc1-00004-g18bc2dec41ab-d4 >>>> [ 142.936580] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_0738364 >>>> [ 142.939318] Call Trace: >>>> [ 142.939662] ? dump_stack_lvl+0x73/0x9f >>>> [ 142.940197] ? print_address_description.constprop.0+0x2f/0x250 >>>> [ 142.941004] ? __rq_qos_done_bio+0x57/0x90 >>>> [ 142.941564] ? __rq_qos_done_bio+0x57/0x90 >>>> [ 142.942132] ? kasan_report.cold+0x81/0x165 >>>> [ 142.942710] ? __rq_qos_done_bio+0x57/0x90 >>>> [ 142.943282] ? __asan_load8+0x74/0x110 >>>> [ 142.943798] ? __rq_qos_done_bio+0x57/0x90 >>>> [ 142.944365] ? bio_endio+0x142/0x430 >>>> [ 142.944864] ? submit_bio_checks+0x178/0xef0 >>>> [ 142.945456] ? trace_event_raw_event_block_rq_requeue+0x300/0x300 >>>> [ 142.946283] ? mempool_alloc+0xe9/0x2f0 >>>> [ 142.946812] ? remove_element+0x130/0x130 >>>> [ 142.947371] ? init_timer_key+0x83/0x1b0 >>>> [ 142.947917] ? submit_bio_noacct+0x86/0x9c0 >>>> [ 142.948496] ? blk_queue_enter+0x6d0/0x6d0 >>>> [ 142.949066] ? bio_alloc_bioset+0x1b2/0x3a0 >>>> [ 142.949649] ? __rcu_read_unlock+0x45/0x370 >>>> [ 142.950227] ? bvec_alloc+0x120/0x120 >>>> [ 142.950732] ? submit_bio+0x60/0x230 >>>> [ 142.951230] ? blk_next_bio+0x4f/0x70 >>>> [ 142.951740] ? __blkdev_issue_discard+0x257/0x520 >>>> [ 142.952387] ? __blkdev_issue_write_zeroes+0x270/0x270 >>>> [ 142.953089] ? bd_abort_claiming+0x70/0x70 >>>> [ 142.953652] ? __kasan_check_write+0x20/0x30 >>>> [ 142.954236] ? _raw_spin_lock+0xaf/0x130 >>>> [ 142.954769] ? _raw_read_lock_bh+0xa0/0xa0 >>>> [ 142.955328] ? __get_locked_pte+0x1b3/0x310 >>>> [ 142.955897] ? _raw_spin_unlock+0x3b/0x80 >>>> [ 142.956444] ? blkdev_issue_discard+0xd3/0x1a0 >>>> [ 142.957051] ? blkdev_issue_write_same+0x540/0x540 >>>> [ 142.957708] ? _raw_spin_lock+0xaf/0x130 >>>> [ 142.958244] ? bd_abort_claiming+0x70/0x70 >>>> [ 142.958805] ? wake_up_bit+0x46/0x50 >>>> [ 142.959302] ? preempt_count_sub+0x14/0x160 >>>> [ 142.959877] ? _raw_spin_unlock+0x3b/0x80 >>>> [ 142.960428] ? bd_abort_claiming+0x65/0x70 >>>> [ 142.960993] ? blk_ioctl_discard+0x1bd/0x240 >>>> [ 142.961582] ? blkdev_bszset+0x1c0/0x1c0 >>>> [ 142.962118] ? special_mapping_fault+0x6f/0x200 >>>> [ 142.962743] ? __do_fault+0x80/0x410 >>>> [ 142.963241] ? blkdev_common_ioctl+0x6c9/0x1190 >>>> [ 142.963877] ? ioctl_file_clone+0x110/0x110 >>>> [ 142.964457] ? blk_ioctl_discard+0x240/0x240 >>>> [ 142.965038] ? copy_page_range+0x2b60/0x2b60 >>>> [ 142.965623] ? vfs_getattr_nosec+0x177/0x190 >>>> [ 142.966214] ? __ia32_compat_sys_newfstat+0x40/0x40 >>>> [ 142.966885] ? blkdev_ioctl+0x180/0x4b0 >>>> [ 142.967409] ? blkdev_common_ioctl+0x1190/0x1190 >>>> [ 142.968033] ? handle_mm_fault+0x3c2/0x660 >>>> [ 142.968590] ? __kasan_check_write+0x20/0x30 >>>> [ 142.969172] ? block_ioctl+0x7d/0xa0 >>>> [ 142.969666] ? __x64_sys_ioctl+0xd5/0x150 >>>> [ 142.970224] ? do_syscall_64+0x35/0x80 >>>> [ 142.970733] ? entry_SYSCALL_64_after_hwframe+0x44/0xae >>>> [ 142.971441] >>>> [ 142.971653] Allocated by task 283: >>>> [ 142.972117] kasan_save_stack+0x23/0x60 >>>> [ 142.972637] set_alloc_info+0x46/0x70 >>>> [ 142.973136] __kasan_kmalloc+0x8d/0xd0 >>>> [ 142.973639] kmem_cache_alloc_trace+0x3e7/0x820 >>>> [ 142.974254] wbt_init+0x40/0x430 >>>> [ 142.974694] wbt_enable_default+0xbb/0x100 >>>> [ 142.975248] blk_register_queue+0x216/0x3e0 >>>> [ 142.975812] device_add_disk+0x4ac/0x880 >>>> [ 142.976358] sd_probe+0x690/0x910 >>>> [ 142.976809] really_probe+0x5c3/0x800 >>>> [ 142.977306] __driver_probe_device+0x233/0x330 >>>> [ 142.977907] driver_probe_device+0x69/0x140 >>>> [ 142.978466] __device_attach_driver+0x125/0x210 >>>> [ 142.979081] bus_for_each_drv+0x10e/0x1b0 >>>> [ 142.979615] __device_attach_async_helper+0x175/0x230 >>>> [ 142.980302] async_run_entry_fn+0x7b/0x310 >>>> [ 142.980859] process_one_work+0x46a/0xa80 >>>> [ 142.981400] worker_thread+0x33d/0x8d0 >>>> [ 142.981917] kthread+0x282/0x300 >>>> [ 142.982363] ret_from_fork+0x1f/0x30 >>>> [ 142.982862] >>>> [ 142.983077] Freed by task 863: >>>> [ 142.983501] kasan_save_stack+0x23/0x60 >>>> [ 142.984029] kasan_set_track+0x24/0x40 >>>> [ 142.984547] kasan_set_free_info+0x30/0x60 >>>> [ 142.985115] __kasan_slab_free+0x137/0x210 >>>> [ 142.985678] kfree+0x10b/0x570 >>>> [ 142.986106] wbt_exit+0x68/0x80 >>>> [ 142.986535] rq_qos_exit+0x5f/0x80 >>>> [ 142.987002] blk_cleanup_queue+0xdb/0x250 >>>> [ 142.987546] __scsi_remove_device+0xb1/0x2e0 >>>> [ 142.988131] scsi_remove_device+0x38/0x60 >>>> [ 142.988676] sdev_store_delete+0x73/0x100 >>>> [ 142.989230] dev_attr_store+0x40/0x70 >>>> [ 142.989730] sysfs_kf_write+0x89/0xc0 >>>> [ 142.990233] kernfs_fop_write_iter+0x21d/0x340 >>>> [ 142.990839] new_sync_write+0x27e/0x3a0 >>>> [ 142.991362] vfs_write+0x46e/0x630 >>>> [ 142.991834] ksys_write+0xcd/0x1e0 >>>> [ 142.992300] __x64_sys_write+0x46/0x60 >>>> [ 142.992814] do_syscall_64+0x35/0x80 >>>> [ 142.993311] entry_SYSCALL_64_after_hwframe+0x44/0xae >>>> [ 142.994213] The buggy address belongs to the object at ffff88810306d800 >>>> [ 142.994213] which belongs to the cache kmalloc-256 of size 256 >>>> [ 142.995889] The buggy address is located 88 bytes inside of >>>> [ 142.995889] 256-byte region [ffff88810306d800, ffff88810306d900) >>>> [ 142.997448] The buggy address belongs to the page: >>>> [ 142.998102] page:0000000069471149 refcount:1 mapcount:0 mapping:0000000000000000 index:0xc >>>> [ 142.999372] head:0000000069471149 order:2 compound_mapcount:0 compound_pincount:0 >>>> [ 143.000375] flags: 0x2fffff80010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff) >>>> [ 143.001403] raw: 002fffff80010200 0000000000000000 0000000100000001 ffff88810004cb40 >>>> [ 143.002455] raw: 0000000000000000 0000000000200020 00000001ffffffff 0000000000000000 >>>> [ 143.003477] page dumped because: kasan: bad access detected >>>> [ 143.004222] >>>> [ 143.004433] Memory state around the buggy address: >>>> [ 143.005077] ffff88810306d700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >>>> [ 143.006040] ffff88810306d780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >>>> [ 143.007012] >ffff88810306d800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >>>> [ 143.007981] ^ >>>> [ 143.008795] ffff88810306d880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >>>> [ 143.009764] ffff88810306d900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >>>> [ 143.010731] ================================================================== >>>> >>>> This is because 'q_usage_counter' will not hold when bio_endio() is >>>> called from error path, thus bio_endio() can concurrent with >>>> blk_cleanup_queue(): >>> >>> What is the exact error path? We actually grabs one ref of q_usage_counter >>> during submitting bio, so the issue should have been fixed by not >>> releasing the refcount early in the error path? Or the refcnt isn't grabbed >>> yet when handling the error? >>> >> >> Hi, >> >> We found at least two places: >> >> The first is error path from submit_bio_checks(), and we succeed to >> construct repoducer here. >> >> The second is from bio_queue_enter(), bio_endio() will be called if >> blk_queue_enter() failed. > > OK, both should be addressed by the following simple patch: > > > diff --git a/block/bio.c b/block/bio.c > index 5df3dd282e40..a6fb6a0b4295 100644 > --- a/block/bio.c > +++ b/block/bio.c > @@ -1466,7 +1466,7 @@ void bio_endio(struct bio *bio) > if (!bio_integrity_endio(bio)) > return; > > - if (bio->bi_bdev) > + if (bio->bi_bdev && bio_flagged(bio, BIO_TRACKED)) > rq_qos_done_bio(bio->bi_bdev->bd_disk->queue, bio); > > if (bio->bi_bdev && bio_flagged(bio, BIO_TRACE_COMPLETION)) { > Hi, This patch looks good to me Thanks, Kuai