Re: [PATCH v7 2/2] certs: Add support for using elliptic curve keys for signing modules
From: Jarkko Sakkinen <jarkko@kernel.org>
Date: 2021-06-29 20:56:44
Also in:
keyrings, linux-security-module, lkml
On Mon, Jun 28, 2021 at 05:43:04PM -0400, Stefan Berger wrote:
From: Stefan Berger <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> Cc: David Howells <dhowells@redhat.com> Cc: David Woodhouse <dwmw2@infradead.org> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> ---
When you change the patches, you should remove all reviewed-by etc. tags. Also, move Cc-tags before your sob. /Jarkko
quoted hunk ↗ jump to hunk
certs/Kconfig | 26 ++++++++++++++++++++++++++ certs/Makefile | 13 +++++++++++++ crypto/asymmetric_keys/pkcs7_parser.c | 8 ++++++++ 3 files changed, 47 insertions(+)diff --git a/certs/Kconfig b/certs/Kconfig index f4e61116f94e..916cbb1af928 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 KEYSdiff --git a/certs/Makefile b/certs/Makefile index f9344e52ecda..279433783b10 100644 --- a/certs/Makefile +++ b/certs/Makefile@@ -66,9 +66,21 @@ ifeq ($(CONFIG_MODULE_SIG_KEY),"certs/signing_key.pem") ifeq ($(openssl_available),yes) X509TEXT=$(shell openssl x509 -in "certs/signing_key.pem" -text 2>/dev/null) +endif +# Support user changing key type +ifdef CONFIG_MODULE_SIG_KEY_TYPE_ECDSA +keytype_openssl = -newkey ec -pkeyopt ec_paramgen_curve:secp384r1 +ifeq ($(openssl_available),yes) +$(if $(findstring id-ecPublicKey,$(X509TEXT)),,$(shell rm -f "certs/signing_key.pem")) +endif +endif # CONFIG_MODULE_SIG_KEY_TYPE_ECDSA + +ifdef CONFIG_MODULE_SIG_KEY_TYPE_RSA +ifeq ($(openssl_available),yes) $(if $(findstring rsaEncryption,$(X509TEXT)),,$(shell rm -f "certs/signing_key.pem")) endif +endif # CONFIG_MODULE_SIG_KEY_TYPE_RSA $(obj)/signing_key.pem: $(obj)/x509.genkey @$(kecho) "###"@@ -83,6 +95,7 @@ $(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;-- 2.31.1