From: Stefan Berger <stefanb@linux.ibm.com>
To: keyrings@vger.kernel.org, dhowells@redhat.com,
zohar@linux.ibm.com, jarkko@kernel.org
Cc: nayna@linux.ibm.com, linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org,
Stefan Berger <stefanb@linux.ibm.com>
Subject: [PATCH v2 2/2] certs: Add support for using elliptic curve keys for signing modules
Date: Thu, 8 Apr 2021 11:24:03 -0400 [thread overview]
Message-ID: <20210408152403.1189121-3-stefanb@linux.ibm.com> (raw)
In-Reply-To: <20210408152403.1189121-1-stefanb@linux.ibm.com>
Add support for using elliptic curve keys for signing modules. It uses
a NIST P384 (secp384r1) key if the user chooses an elliptic curve key
and will have ECDSA support built into the kernel.
Note: A developer choosing an ECDSA key for signing modules should still
delete the signing key (rm certs/signing_key.*) when building an older
version of a kernel that only supports RSA keys. Unless kbuild automati-
cally detects and generates a new kernel module key, ECDSA-signed kernel
modules will fail signature verification.
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
---
v2:
- check for ECDSA key by id-ecPublicKey from output line
'Public Key Algorithm: id-ecPublicKey'.
---
certs/Kconfig | 25 +++++++++++++++++++++++++
certs/Makefile | 9 +++++++++
crypto/asymmetric_keys/pkcs7_parser.c | 4 ++++
3 files changed, 38 insertions(+)
diff --git a/certs/Kconfig b/certs/Kconfig
index 48675ad319db..6f8337874ae0 100644
--- a/certs/Kconfig
+++ b/certs/Kconfig
@@ -15,6 +15,31 @@ config MODULE_SIG_KEY
then the kernel will automatically generate the private key and
certificate as described in Documentation/admin-guide/module-signing.rst
+choice
+ prompt "Type of module signing key to be generated"
+ default MODULE_SIG_KEY_TYPE_RSA
+ help
+ The type of module signing key type to generate. This option
+ does not apply if a #PKCS11 URI is used.
+
+config MODULE_SIG_KEY_TYPE_RSA
+ bool "RSA"
+ depends on MODULE_SIG || IMA_APPRAISE_MODSIG
+ help
+ Use an RSA key for module signing.
+
+config MODULE_SIG_KEY_TYPE_ECDSA
+ bool "ECDSA"
+ select CRYPTO_ECDSA
+ depends on MODULE_SIG || IMA_APPRAISE_MODSIG
+ help
+ Use an elliptic curve key (NIST P384) for module signing.
+
+ Note: Remove all ECDSA signing keys, e.g. certs/signing_key.pem,
+ when falling back to building Linux 5.11 and older kernels.
+
+endchoice
+
config SYSTEM_TRUSTED_KEYRING
bool "Provide system-wide ring of trusted keys"
depends on KEYS
diff --git a/certs/Makefile b/certs/Makefile
index f64bc89ccbf1..c2fabc288550 100644
--- a/certs/Makefile
+++ b/certs/Makefile
@@ -62,7 +62,15 @@ ifeq ($(CONFIG_MODULE_SIG_KEY),"certs/signing_key.pem")
X509TEXT=$(shell openssl x509 -in $(CONFIG_MODULE_SIG_KEY) -text)
+# Support user changing key type
+ifdef CONFIG_MODULE_SIG_KEY_TYPE_ECDSA
+keytype_openssl = -newkey ec -pkeyopt ec_paramgen_curve:secp384r1
+$(if $(findstring id-ecPublicKey,$(X509TEXT)),,$(shell rm -f $(CONFIG_MODULE_SIG_KEY)))
+endif
+
+ifdef CONFIG_MODULE_SIG_KEY_TYPE_RSA
$(if $(findstring rsaEncryption,$(X509TEXT)),,$(shell rm -f $(CONFIG_MODULE_SIG_KEY)))
+endif
$(obj)/signing_key.pem: $(obj)/x509.genkey
@$(kecho) "###"
@@ -77,6 +85,7 @@ $(obj)/signing_key.pem: $(obj)/x509.genkey
-batch -x509 -config $(obj)/x509.genkey \
-outform PEM -out $(obj)/signing_key.pem \
-keyout $(obj)/signing_key.pem \
+ $(keytype_openssl) \
$($(quiet)redirect_openssl)
@$(kecho) "###"
@$(kecho) "### Key pair generated."
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;
default:
printk("Unsupported pkey algo: %u\n", ctx->last_oid);
return -ENOPKG;
--
2.29.2
next prev parent reply other threads:[~2021-04-08 15:24 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 ` Stefan Berger [this message]
2021-04-08 17:15 ` [PATCH v2 2/2] certs: Add support for using elliptic curve keys for signing modules Mimi Zohar
2021-04-20 14:03 ` Jessica Yu
2021-04-20 21:02 ` Stefan Berger
2021-04-21 12:52 ` Jessica Yu
2021-04-21 12:54 ` Stefan Berger
2021-04-21 12:58 ` Jessica Yu
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