From: Sergei Shtepa <sergei.shtepa@veeam.com>
To: Yu Kuai <yukuai1@huaweicloud.com>, <axboe@kernel.dk>,
<hch@infradead.org>, <corbet@lwn.net>, <snitzer@kernel.org>
Cc: <viro@zeniv.linux.org.uk>, <brauner@kernel.org>,
<dchinner@redhat.com>, <willy@infradead.org>,
<dlemoal@kernel.org>, <linux@weissschuh.net>, <jack@suse.cz>,
<ming.lei@redhat.com>, <linux-block@vger.kernel.org>,
<linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-fsdevel@vger.kernel.org>,
Donald Buczek <buczek@molgen.mpg.de>,
"yukuai (C)" <yukuai3@huawei.com>
Subject: Re: [PATCH v5 02/11] block: Block Device Filtering Mechanism
Date: Mon, 17 Jul 2023 18:22:46 +0200 [thread overview]
Message-ID: <3a86aa81-83ff-6245-bc10-304bde8c200d@veeam.com> (raw)
In-Reply-To: <eca5a778-6795-fc03-7ae0-fe06f514af85@huaweicloud.com>
On 7/12/23 12:04, Yu Kuai wrote:
> Subject:
> Re: [PATCH v5 02/11] block: Block Device Filtering Mechanism
> From:
> Yu Kuai <yukuai1@huaweicloud.com>
> Date:
> 7/12/23, 12:04
>
> To:
> Yu Kuai <yukuai1@huaweicloud.com>, Sergei Shtepa <sergei.shtepa@veeam.com>, axboe@kernel.dk, hch@infradead.org, corbet@lwn.net, snitzer@kernel.org
> CC:
> viro@zeniv.linux.org.uk, brauner@kernel.org, dchinner@redhat.com, willy@infradead.org, dlemoal@kernel.org, linux@weissschuh.net, jack@suse.cz, ming.lei@redhat.com, linux-block@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Donald Buczek <buczek@molgen.mpg.de>, "yukuai (C)" <yukuai3@huawei.com>
>
>
> Hi,
>
> 在 2023/07/11 10:02, Yu Kuai 写道:
>
>>> +static bool submit_bio_filter(struct bio *bio)
>>> +{
>>> + if (bio_flagged(bio, BIO_FILTERED))
>>> + return false;
>>> +
>>> + bio_set_flag(bio, BIO_FILTERED);
>>> + return bio->bi_bdev->bd_filter->ops->submit_bio(bio);
>>> +}
>>> +
>>> static void __submit_bio(struct bio *bio)
>>> {
>>> + /*
>>> + * If there is a filter driver attached, check if the BIO needs to go to
>>> + * the filter driver first, which can then pass on the bio or consume it.
>>> + */
>>> + if (bio->bi_bdev->bd_filter && submit_bio_filter(bio))
>>> + return;
>>> +
>>> if (unlikely(!blk_crypto_bio_prep(&bio)))
>>> return;
>
> ...
>
>>> +static void __blkfilter_detach(struct block_device *bdev)
>>> +{
>>> + struct blkfilter *flt = bdev->bd_filter;
>>> + const struct blkfilter_operations *ops = flt->ops;
>>> +
>>> + bdev->bd_filter = NULL;
>>> + ops->detach(flt);
>>> + module_put(ops->owner);
>>> +}
>>> +
>>> +void blkfilter_detach(struct block_device *bdev)
>>> +{
>>> + if (bdev->bd_filter) {
>>> + blk_mq_freeze_queue(bdev->bd_queue);
>
> And this is not sate as well, for bio-based device, q_usage_counter is
> not grabbed while submit_bio_filter() is called, hence there is a risk
> of uaf from submit_bio_filter().
>
> Thanks,
> Kuai
>
Hi Kuai.
Indeed, the filter call is performed before calling bio_queue_enter().
I must admit, you are very attentive.
I didn't keep track of the change in the position of the
bio_queue_enter() function deeper on the stack.
I think I need to add a check for q_usage_counter, for the debug build.
So that I don't miss it in the future.
next prev parent reply other threads:[~2023-07-17 16:23 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-12 13:52 [PATCH v5 00/11] blksnap - block devices snapshots module Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 01/11] documentation: Block Device Filtering Mechanism Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 02/11] block: " Sergei Shtepa
2023-07-11 2:02 ` Yu Kuai
2023-07-12 10:04 ` Yu Kuai
2023-07-12 12:34 ` Yu Kuai
2023-07-17 17:39 ` Sergei Shtepa
2023-07-18 1:21 ` Yu Kuai
2023-07-17 16:22 ` Sergei Shtepa [this message]
2023-07-17 14:39 ` Sergei Shtepa
2023-07-18 1:37 ` Yu Kuai
2023-07-18 11:25 ` Sergei Shtepa
2023-07-18 12:32 ` Yu Kuai
2023-07-18 16:33 ` Sergei Shtepa
2023-07-19 7:28 ` Yu Kuai
2023-07-19 8:36 ` Sergei Shtepa
2023-07-20 6:14 ` Christoph Hellwig
2023-06-12 13:52 ` [PATCH v5 03/11] documentation: Block Devices Snapshots Module Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 04/11] blksnap: header file of the module interface Sergei Shtepa
2023-06-13 22:25 ` Dave Chinner
2023-06-14 6:26 ` Christoph Hellwig
2023-06-14 9:26 ` Sergei Shtepa
2023-06-14 14:07 ` Christoph Hellwig
2023-06-14 16:43 ` Sergei Shtepa
2023-06-15 0:08 ` Dave Chinner
2023-07-17 18:57 ` Thomas Weißschuh
2023-07-18 9:53 ` Sergei Shtepa
2023-07-20 6:16 ` Christoph Hellwig
2023-06-12 13:52 ` [PATCH v5 05/11] blksnap: module management interface functions Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 06/11] blksnap: handling and tracking I/O units Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 07/11] blksnap: minimum data storage unit of the original block device Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 08/11] blksnap: difference storage Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 09/11] blksnap: event queue from the " Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 10/11] blksnap: snapshot and snapshot image block device Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 11/11] blksnap: Kconfig and Makefile Sergei Shtepa
2023-06-12 14:32 ` [PATCH v5 00/11] blksnap - block devices snapshots module Christoph Hellwig
2023-06-12 16:19 ` Eric Biggers
2023-06-13 5:50 ` Christoph Hellwig
2023-06-13 10:12 ` Sergei Shtepa
2023-06-14 17:22 ` Eric Biggers
-- strict thread matches above, loose matches on Subject: below --
2023-06-12 13:21 Sergei Shtepa
2023-06-12 13:21 ` [PATCH v5 02/11] block: Block Device Filtering Mechanism Sergei Shtepa
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