From: Jessica Yu <jeyu@kernel.org>
To: Stefan Berger <stefanb@linux.ibm.com>
Cc: keyrings@vger.kernel.org, dhowells@redhat.com,
zohar@linux.ibm.com, jarkko@kernel.org, nayna@linux.ibm.com,
linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] certs: Add support for using elliptic curve keys for signing modules
Date: Wed, 21 Apr 2021 14:52:06 +0200 [thread overview]
Message-ID: <YIAf9jYGu03lrJLn@gunter> (raw)
In-Reply-To: <794ef635-de91-9207-f28b-ab6805fd95c9@linux.ibm.com>
+++ Stefan Berger [20/04/21 17:02 -0400]:
>
>On 4/20/21 10:03 AM, Jessica Yu wrote:
>>+++ Stefan Berger [08/04/21 11:24 -0400]:
>>>
>>>diff --git a/crypto/asymmetric_keys/pkcs7_parser.c
>>>b/crypto/asymmetric_keys/pkcs7_parser.c
>>>index 967329e0a07b..2546ec6a0505 100644
>>>--- a/crypto/asymmetric_keys/pkcs7_parser.c
>>>+++ b/crypto/asymmetric_keys/pkcs7_parser.c
>>>@@ -269,6 +269,10 @@ int pkcs7_sig_note_pkey_algo(void *context,
>>>size_t hdrlen,
>>> ctx->sinfo->sig->pkey_algo = "rsa";
>>> ctx->sinfo->sig->encoding = "pkcs1";
>>> break;
>>>+ case OID_id_ecdsa_with_sha256:
>>>+ ctx->sinfo->sig->pkey_algo = "ecdsa";
>>>+ ctx->sinfo->sig->encoding = "x962";
>>>+ break;
>>
>>Hi Stefan,
>>
>>Does CONFIG_MODULE_SIG_KEY_TYPE_ECDSA have a dependency on
>>MODULE_SIG_SHA256?
>
>You are right, per the code above it does have a dependency on SHA256.
>ECDSA is using NIST p384 (secp384r1) for signing and per my tests it
>can be paired with all the sha hashes once the code above is extended.
>Now when it comes to module signing, should we pair it with a
>particular hash? I am not currently aware of a guidance document on
>this but sha256 and sha384 seem to be good choices these days, so
>maybe selecting ECDSA module signing should have a 'depends on' on
>these?
Yeah, I would tack on the 'depends on' until the code above has been
extended to cover more sha hashes - because currently if someone
builds and signs a bunch of modules with an ECDSA key, they will fail
to load if they picked something other than sha256. I am unfortunately
not knowledgeable enough to suggest an official guideline on choice of
hash, but for now it is reasonable to have a 'depends on' for which
hashes the code currently supports, so that users don't run into
module loading rejection issues.
Thanks!
Jessica
next prev parent reply other threads:[~2021-04-21 12:52 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-08 15:24 [PATCH v2 0/2] Add support for ECDSA-signed kernel modules Stefan Berger
2021-04-08 15:24 ` [PATCH v2 1/2] certs: Trigger creation of RSA module signing key if it's not an RSA key Stefan Berger
2021-04-08 17:15 ` Mimi Zohar
2021-04-08 19:19 ` Stefan Berger
2021-04-08 21:34 ` Mimi Zohar
2021-04-08 15:24 ` [PATCH v2 2/2] certs: Add support for using elliptic curve keys for signing modules Stefan Berger
2021-04-08 17:15 ` Mimi Zohar
2021-04-20 14:03 ` Jessica Yu
2021-04-20 21:02 ` Stefan Berger
2021-04-21 12:52 ` Jessica Yu [this message]
2021-04-21 12:54 ` Stefan Berger
2021-04-21 12:58 ` Jessica Yu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YIAf9jYGu03lrJLn@gunter \
--to=jeyu@kernel.org \
--cc=dhowells@redhat.com \
--cc=jarkko@kernel.org \
--cc=keyrings@vger.kernel.org \
--cc=linux-integrity@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=nayna@linux.ibm.com \
--cc=stefanb@linux.ibm.com \
--cc=zohar@linux.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).