From patchwork Fri Nov 24 16:59:33 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sergei Shtepa X-Patchwork-Id: 13468012 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="YS/3MDkQ" Received: from out-188.mta0.migadu.com (out-188.mta0.migadu.com [IPv6:2001:41d0:1004:224b::bc]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A50561BCF for ; Fri, 24 Nov 2023 09:00:30 -0800 (PST) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1700845228; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QWk7YTMvB3DTfZc9sNUwNxdg+CAbRo1hOQbqO2wSQ6A=; b=YS/3MDkQDJLZ1KOe1iNDAZDteB/JflqObZ/sxnSGYirEVXMmWDGjQitpPoxMWbwITRRGcK lCaiEJ8jACRUkhE5INGw8DLQ17uYGYUcBA+kCBAPjM3CKQX83iJY0AdVDX5aUYv45OjLes yYiDU6Zy3ApLCGmeU0KMq1smX6MXIK4= From: Sergei Shtepa To: axboe@kernel.dk, hch@infradead.org, corbet@lwn.net, snitzer@kernel.org Cc: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, viro@zeniv.linux.org.uk, brauner@kernel.org, linux-block@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Sergei Shtepa , Eric Biggers Subject: [PATCH v6 11/11] blksnap: prevents using devices with data integrity or inline encryption Date: Fri, 24 Nov 2023 17:59:33 +0100 Message-Id: <20231124165933.27580-12-sergei.shtepa@linux.dev> In-Reply-To: <20231124165933.27580-1-sergei.shtepa@linux.dev> References: <20231124165933.27580-1-sergei.shtepa@linux.dev> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT From: Sergei Shtepa There is an opinion that the use of the blksnap module may violate the security of encrypted data. The difference storage file may be located on an unreliable disk or even network storage. To implement secure compatibility with hardware inline encrypted devices will require discussion of algorithms and restrictions. For example, a restriction on the location of the difference storage only in virtual memory might help. Currently, there is no need for compatibility of the blksnap module and hardware inline encryption. I see no obstacles to ensuring the compatibility of the blksnap module and block devices with data integrity. However, this functionality was not planned or tested. Perhaps in the future this compatibility can be implemented. Theoretically possible that the block device was added to the snapshot before crypto_profile and integrity.profile were initialized. Checking the values of bi_crypt_context and bi_integrity ensures that the blksnap will not perform any actions with I/O units with which it is not compatible. Reported-by: Eric Biggers Signed-off-by: Sergei Shtepa --- drivers/block/blksnap/snapshot.c | 17 +++++++++++++++++ drivers/block/blksnap/tracker.c | 14 ++++++++++++++ 2 files changed, 31 insertions(+) diff --git a/drivers/block/blksnap/snapshot.c b/drivers/block/blksnap/snapshot.c index 21d94f12b5fc..a7675fdcf359 100644 --- a/drivers/block/blksnap/snapshot.c +++ b/drivers/block/blksnap/snapshot.c @@ -149,6 +149,23 @@ int snapshot_add_device(const uuid_t *id, struct tracker *tracker) int ret = 0; struct snapshot *snapshot = NULL; +#ifdef CONFIG_BLK_DEV_INTEGRITY + if (tracker->orig_bdev->bd_disk->queue->integrity.profile) { + pr_err("Blksnap is not compatible with data integrity\n"); + ret = -EPERM; + goto out_up; + } else + pr_debug("Data integrity not found\n"); +#endif + +#ifdef CONFIG_BLK_INLINE_ENCRYPTION + if (tracker->orig_bdev->bd_disk->queue->crypto_profile) { + pr_err("Blksnap is not compatible with hardware inline encryption\n"); + ret = -EPERM; + goto out_up; + } else + pr_debug("Inline encryption not found\n"); +#endif snapshot = snapshot_get_by_id(id); if (!snapshot) return -ESRCH; diff --git a/drivers/block/blksnap/tracker.c b/drivers/block/blksnap/tracker.c index 2b8978a2f42e..b38ead9afa69 100644 --- a/drivers/block/blksnap/tracker.c +++ b/drivers/block/blksnap/tracker.c @@ -57,6 +57,20 @@ static bool tracker_submit_bio(struct bio *bio) if (diff_area_is_corrupted(tracker->diff_area)) return false; +#ifdef CONFIG_BLK_INLINE_ENCRYPTION + if (bio->bi_crypt_context) { + pr_err_once("Hardware inline encryption is not supported\n"); + diff_area_set_corrupted(tracker->diff_area, -EPERM); + return false; + } +#endif +#ifdef CONFIG_BLK_DEV_INTEGRITY + if (bio->bi_integrity) { + pr_err_once("Data integrity is not supported\n"); + diff_area_set_corrupted(tracker->diff_area, -EPERM); + return false; + } +#endif return diff_area_cow(bio, tracker->diff_area, ©_iter); }