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From: Eric Biggers <ebiggers@kernel.org>
To: Maxime Ripard <maxime@cerno.tech>
Cc: linux-mmc@vger.kernel.org, Ulf Hansson <ulf.hansson@linaro.org>
Subject: Re: Help with eMMC inline encryption
Date: Mon, 22 Mar 2021 10:02:52 -0700	[thread overview]
Message-ID: <YFjNvGAu8M/+ERCo@gmail.com> (raw)
In-Reply-To: <20210322155318.yg4u634a7fxg2yiq@gilmour>

On Mon, Mar 22, 2021 at 04:53:18PM +0100, Maxime Ripard wrote:
> 
> Indeed, I somehow missed that you were setting the DUN in
> cqhci_crypto_prep_task_desc, and I'm guessing that's where my issue
> lies: it doesn't look like there's any field to set the DUN in the
> controller, which doesn't make much sense to me.
> 
> The documentation is pretty short, but it looks like it might be
> inferred from the MMC commands arguments (the Access Mode bit in the MMC
> controller, page 517). Would that make sense?
> 

If your hardware has no way to specify a starting DUN (or starting IV) for each
request, then presumably it automatically chooses IVs based on the location of
the data on-disk.

This way of IV generation is problematic for several reasons, and it doesn't
match the UFS and eMMC standards.  So blk-crypto and fscrypt don't support this
type of hardware.

- Eric

  reply	other threads:[~2021-03-22 17:03 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-17 17:15 Help with eMMC inline encryption Maxime Ripard
2021-03-17 18:33 ` Eric Biggers
2021-03-22 15:53   ` Maxime Ripard
2021-03-22 17:02     ` Eric Biggers [this message]
2021-03-23 10:53       ` Maxime Ripard

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