Re: [RFC PATCH v5 1/1] Add dm verity root hash pkcs7 sig validation.

From: Jaskaran Singh Khurana
Date: Thu Jun 27 2019 - 21:50:01 EST

On Thu, 27 Jun 2019, Eric Biggers wrote:

Hi Jaskaran, one comment (I haven't reviewed this in detail):

On Wed, Jun 19, 2019 at 12:10:48PM -0700, Jaskaran Khurana wrote:
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index db269a348b20..2d658a3512cb 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -475,6 +475,7 @@ config DM_VERITY
select CRYPTO
select DM_BUFIO
This device-mapper target creates a read-only device that
transparently validates the data on one underlying device against
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index be7a6eb92abc..3b47b256b15e 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -18,7 +18,7 @@ dm-cache-y += dm-cache-target.o dm-cache-metadata.o dm-cache-policy.o \
dm-cache-smq-y += dm-cache-policy-smq.o
dm-era-y += dm-era-target.o
-dm-verity-y += dm-verity-target.o
+dm-verity-y += dm-verity-target.o dm-verity-verify-sig.o
md-mod-y += md.o md-bitmap.o
raid456-y += raid5.o raid5-cache.o raid5-ppl.o
dm-zoned-y += dm-zoned-target.o dm-zoned-metadata.o dm-zoned-reclaim.o

Perhaps this should be made optional and controlled by a kconfig option

CONFIG_SYSTEM_DATA_VERIFICATION brings in a lot of stuff, which might be
unnecessary for some dm-verity users. Also, you've already separated most of
the code out into a separate .c file anyway.

- Eric

Hello Eric,

This started with a config (see V4). We didnot want scripts that pass this parameter to suddenly stop working if for some reason the verification is turned off so the optional parameter was just parsed and no validation happened if the CONFIG was turned off. This was changed to a commandline parameter after feedback from the community, so I would prefer to keep it *now* as commandline parameter. Let me know if you are OK with this.