* [PATCH v4 1/2] certs: Trigger creation of RSA module signing key if it's not an RSA key
2021-04-23 15:12 [PATCH v4 0/2] Add support for ECDSA-signed kernel modules Stefan Berger
@ 2021-04-23 15:12 ` Stefan Berger
2021-05-31 16:12 ` Mimi Zohar
2021-04-23 15:12 ` [PATCH v4 2/2] certs: Add support for using elliptic curve keys for signing modules Stefan Berger
2021-04-27 23:47 ` [PATCH v4 0/2] Add support for ECDSA-signed kernel modules Jarkko Sakkinen
2 siblings, 1 reply; 6+ messages in thread
From: Stefan Berger @ 2021-04-23 15:12 UTC (permalink / raw)
To: jeyu, keyrings, dhowells, zohar, jarkko
Cc: nayna, linux-integrity, linux-security-module, linux-kernel,
Stefan Berger
Address a kbuild issue where a developer created an ECDSA key for signing
kernel modules and then builds an older version of the kernel, when bi-
secting the kernel for example, that does not support ECDSA keys.
Trigger the creation of an RSA module signing key if it is not an RSA key.
Fixes: cfc411e7fff3 ("Move certificate handling to its own directory")
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
---
certs/Makefile | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/certs/Makefile b/certs/Makefile
index e3185c57fbd8..f64bc89ccbf1 100644
--- a/certs/Makefile
+++ b/certs/Makefile
@@ -59,6 +59,11 @@ silent_redirect_openssl = 2>/dev/null
# external private key, because 'make randconfig' might enable such a
# boolean option and we unfortunately can't make it depend on !RANDCONFIG.
ifeq ($(CONFIG_MODULE_SIG_KEY),"certs/signing_key.pem")
+
+X509TEXT=$(shell openssl x509 -in $(CONFIG_MODULE_SIG_KEY) -text)
+
+$(if $(findstring rsaEncryption,$(X509TEXT)),,$(shell rm -f $(CONFIG_MODULE_SIG_KEY)))
+
$(obj)/signing_key.pem: $(obj)/x509.genkey
@$(kecho) "###"
@$(kecho) "### Now generating an X.509 key pair to be used for signing modules."
--
2.29.2
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v4 1/2] certs: Trigger creation of RSA module signing key if it's not an RSA key
2021-04-23 15:12 ` [PATCH v4 1/2] certs: Trigger creation of RSA module signing key if it's not an RSA key Stefan Berger
@ 2021-05-31 16:12 ` Mimi Zohar
0 siblings, 0 replies; 6+ messages in thread
From: Mimi Zohar @ 2021-05-31 16:12 UTC (permalink / raw)
To: Stefan Berger, jeyu, keyrings, dhowells, jarkko
Cc: nayna, linux-integrity, linux-security-module, linux-kernel
On Fri, 2021-04-23 at 11:12 -0400, Stefan Berger wrote:
> Address a kbuild issue where a developer created an ECDSA key for signing
> kernel modules and then builds an older version of the kernel, when bi-
> secting the kernel for example, that does not support ECDSA keys.
>
> Trigger the creation of an RSA module signing key if it is not an RSA key.
>
> Fixes: cfc411e7fff3 ("Move certificate handling to its own directory")
> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Tested-by: Mimi Zohar <zohar@linux.ibm.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v4 2/2] certs: Add support for using elliptic curve keys for signing modules
2021-04-23 15:12 [PATCH v4 0/2] Add support for ECDSA-signed kernel modules Stefan Berger
2021-04-23 15:12 ` [PATCH v4 1/2] certs: Trigger creation of RSA module signing key if it's not an RSA key Stefan Berger
@ 2021-04-23 15:12 ` Stefan Berger
2021-05-31 16:12 ` Mimi Zohar
2021-04-27 23:47 ` [PATCH v4 0/2] Add support for ECDSA-signed kernel modules Jarkko Sakkinen
2 siblings, 1 reply; 6+ messages in thread
From: Stefan Berger @ 2021-04-23 15:12 UTC (permalink / raw)
To: jeyu, keyrings, dhowells, zohar, jarkko
Cc: nayna, linux-integrity, linux-security-module, linux-kernel,
Stefan Berger
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>
---
v4:
- extending 'depends on' with MODULES to (IMA_APPRAISE_MODSIG && MODULES)
v3:
- added missing OIDs for ECDSA signed hashes to pkcs7_sig_note_pkey_algo
- added recommendation to use string hash to Kconfig help text
v2:
- check for ECDSA key by id-ecPublicKey from output line
'Public Key Algorithm: id-ecPublicKey'.
---
certs/Kconfig | 26 ++++++++++++++++++++++++++
certs/Makefile | 9 +++++++++
crypto/asymmetric_keys/pkcs7_parser.c | 8 ++++++++
3 files changed, 43 insertions(+)
diff --git a/certs/Kconfig b/certs/Kconfig
index 48675ad319db..4c0e6113c710 100644
--- a/certs/Kconfig
+++ b/certs/Kconfig
@@ -15,6 +15,32 @@ 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 && MODULES)
+ 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 && MODULES)
+ help
+ Use an elliptic curve key (NIST P384) for module signing. Consider
+ using a strong hash like sha256 or sha384 for hashing modules.
+
+ 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..6592279d839a 100644
--- a/crypto/asymmetric_keys/pkcs7_parser.c
+++ b/crypto/asymmetric_keys/pkcs7_parser.c
@@ -269,6 +269,14 @@ 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_sha1:
+ case OID_id_ecdsa_with_sha224:
+ case OID_id_ecdsa_with_sha256:
+ case OID_id_ecdsa_with_sha384:
+ case OID_id_ecdsa_with_sha512:
+ 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
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v4 2/2] certs: Add support for using elliptic curve keys for signing modules
2021-04-23 15:12 ` [PATCH v4 2/2] certs: Add support for using elliptic curve keys for signing modules Stefan Berger
@ 2021-05-31 16:12 ` Mimi Zohar
0 siblings, 0 replies; 6+ messages in thread
From: Mimi Zohar @ 2021-05-31 16:12 UTC (permalink / raw)
To: Stefan Berger, jeyu, keyrings, dhowells, jarkko
Cc: nayna, linux-integrity, linux-security-module, linux-kernel
On Fri, 2021-04-23 at 11:12 -0400, Stefan Berger wrote:
> 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>
Tested-by: Mimi Zohar <zohar@linux.ibm.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v4 0/2] Add support for ECDSA-signed kernel modules
2021-04-23 15:12 [PATCH v4 0/2] Add support for ECDSA-signed kernel modules Stefan Berger
2021-04-23 15:12 ` [PATCH v4 1/2] certs: Trigger creation of RSA module signing key if it's not an RSA key Stefan Berger
2021-04-23 15:12 ` [PATCH v4 2/2] certs: Add support for using elliptic curve keys for signing modules Stefan Berger
@ 2021-04-27 23:47 ` Jarkko Sakkinen
2 siblings, 0 replies; 6+ messages in thread
From: Jarkko Sakkinen @ 2021-04-27 23:47 UTC (permalink / raw)
To: Stefan Berger
Cc: jeyu, keyrings, dhowells, zohar, nayna, linux-integrity,
linux-security-module, linux-kernel
On Fri, Apr 23, 2021 at 11:12:45AM -0400, Stefan Berger wrote:
> This series adds support for ECDSA-signed kernel modules. It also
> attempts to address a kbuild issue where a developer created an ECDSA
> key for signing kernel modules and then builds an older version of the
> kernel, when bisecting the kernel for example, that does not support
> ECDSA keys.
>
> The first patch addresses the kbuild issue of needing to delete that
> ECDSA key if it is in certs/signing_key.pem and trigger the creation
> of an RSA key. However, for this to work this patch would have to be
> backported to previous versions of the kernel but would also only work
> for the developer if he/she used a stable version of the kernel to which
> this patch was applied. So whether this patch actually achieves the
> wanted effect is not always guaranteed.
>
> The 2nd patch adds the support for the ECSDA-signed kernel modules.
>
> This patch depends on the ECDSA support series currently queued here:
> https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git/log/?h=ecc
>
> Stefan
>
> v4:
> - extending 'depends on' with MODULES to (IMA_APPRAISE_MODSIG && MODULES)
>
> v3:
> - added missing OIDs for ECDSA signed hashes to pkcs7_sig_note_pkey_algo
> - added recommendation to use string hash to Kconfig help text
>
> v2:
> - Adjustment to ECDSA key detector string in 2/2
> - Rephrased cover letter and patch descriptions with Mimi
>
>
> Stefan Berger (2):
> certs: Trigger creation of RSA module signing key if it's not an RSA
> key
> certs: Add support for using elliptic curve keys for signing modules
>
> certs/Kconfig | 26 ++++++++++++++++++++++++++
> certs/Makefile | 14 ++++++++++++++
> crypto/asymmetric_keys/pkcs7_parser.c | 8 ++++++++
> 3 files changed, 48 insertions(+)
>
> --
> 2.29.2
>
>
I just went through v3. My tags apply also to this version.
/Jarkko
^ permalink raw reply [flat|nested] 6+ messages in thread