Thread (5 messages) 5 messages, 2 authors, 2021-02-02

Re: [PATCH 2/2] dm crypt: support using trusted keys

From: Ahmad Fatoum <a.fatoum@pengutronix.de>
Date: 2021-02-02 15:15:56
Also in: dm-devel, keyrings, linux-doc, linux-raid, lkml

On 22.01.21 20:04, Ahmad Fatoum wrote:
On 22.01.21 19:18, Jarkko Sakkinen wrote:
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On Fri, Jan 22, 2021 at 08:05:51PM +0200, Jarkko Sakkinen wrote:
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On Fri, Jan 22, 2021 at 09:43:21AM +0100, Ahmad Fatoum wrote:
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Commit 27f5411a718c ("dm crypt: support using encrypted keys") extended
dm-crypt to allow use of "encrypted" keys along with "user" and "logon".

Along the same lines, teach dm-crypt to support "trusted" keys as well.
Gentle ping.
Is there anything further you require from me regarding these two patches?
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Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
Is it possible to test run this with tmpfs? Would be a good test
target for Sumit's ARM-TEE trusted keys patches.
I tested these on top of Sumit's patches with TPM and a CAAM blobifier
backend, I am preparing. The system I am developing these patches against
doesn't have a TEE.  Steps to test these changes:

#!/bin/sh

DEV=/dev/loop0
ALGO=aes-cbc-essiv:sha256
KEYNAME=kmk
BLOCKS=20

fallocate -l $((BLOCKS*512)) /tmp/loop0.img
losetup -P $DEV /tmp/loop0.img
mount -o remount,rw /
KEY="$(keyctl add trusted $KEYNAME 'new 32' @s)"
keyctl pipe $KEY >$HOME/kmk.blob

TABLE="0 $BLOCKS crypt $ALGO :32:trusted:$KEYNAME 0 $DEV 0 1 allow_discards"
echo $TABLE | dmsetup create mydev
echo $TABLE | dmsetup load mydev
dd if=/dev/zero of=/dev/mapper/mydev
echo "It works!" 1<> /dev/mapper/mydev
cryptsetup close mydev

reboot

DEV=/dev/loop0
ALGO=aes-cbc-essiv:sha256
KEYNAME=kmk
BLOCKS=20

losetup -P $DEV $HOME/loop0.img
keyctl add trusted $KEYNAME "load $(cat $HOME/kmk.blob)" @s
TABLE="0 $BLOCKS crypt $ALGO :32:trusted:$KEYNAME 0 $DEV 0 1 allow_discards"
echo $TABLE | dmsetup create mydev
echo $TABLE | dmsetup load mydev

# should print that It works!
hexdump -C /dev/mapper/mydev
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https://lore.kernel.org/linux-integrity/1604419306-26105-1-git-send-email-sumit.garg@linaro.org/ (local)
Also, I would hold merging *this* patch up until we are able to
test TEE trusted keys with TEE trusted keys.
Which blocks which? I tested this with TPM-Trusted keys, so it's usable
as is. For convenient usage, it would be nice to have cryptsetup
support for trusted and encrypted keys. I intended to look at this next week.

Cheers,
Ahmad
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/Jarkko
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