[v8,0/4] Add support for x509 certs with NIST p256 and p192 keys

Message

Stefan Berger Feb. 15, 2021, 4:25 p.m. UTC

This series of patches adds support for x509 certificates signed by a CA
that uses NIST p256 or p192 keys for signing. It also adds support for
certificates where the public key is a NIST p256 or p192 key. The math
for ECDSA signature verification is also added.

Since self-signed certificates are verified upon loading, the following
script can be used for testing:

k=$(keyctl newring test @u)

while :; do
	for hash in sha1 sha224 sha256 sha384 sha512; do
		openssl req \
			-x509 \
			-${hash} \
			-newkey ec \
			-pkeyopt ec_paramgen_curve:prime256v1 \
			-keyout key.pem \
			-days 365 \
			-subj '/CN=test' \
			-nodes \
			-outform der \
			-out cert.der
		keyctl padd asymmetric testkey $k < cert.der
		if [ $? -ne 0 ]; then
			echo "ERROR"
			exit 1
		fi
	done
done

Ecdsa support also works with restricted keyrings where an RSA key is used
to sign a NIST P256/P192 key. Scripts for testing are here:

https://github.com/stefanberger/eckey-testing

The ECDSA signature verification will be used by IMA Appraisal where ECDSA
file signatures stored in RPM packages will use substantially less space
than if RSA signatures were to be used.

   Stefan

v7->v8:
  - patch 3/4: Do not determine key algo using parse_OID in public_key.c
    but do this when parsing the certificate. This addresses an issue
    with certain build configurations where OID_REGISTRY is not available
    as 'Reported-by: kernel test robot <[e-mail]>'.

v6->v7:
  - Moved some OID defintions to patch 1 for bisectability
  - Applied R-b's
  
v5->v6:
  - moved ecdsa code into its own module ecdsa_generic built from ecdsa.c
  - added script-generated test vectors for NIST P256 & P192 and all hashes
  - parsing of OID that contain header with new parse_oid()

v4->v5:
  - registering crypto support under names ecdsa-nist-p256/p192 following
    Hubert Xu's suggestion in other thread
  - appended IMA ECDSA support patch

v3->v4:
  - split off of ecdsa crypto part; registering akcipher as "ecdsa" and
    deriving used curve from digits in parsed key

v2->v3:
  - patch 2 now includes linux/scatterlist.h

v1->v2:
  - using faster vli_sub rather than newly added vli_mod_fast to 'reduce'
    result
  - rearranged switch statements to follow after RSA
  - 3rd patch from 1st posting is now 1st patch


Stefan Berger (4):
  crypto: Add support for ECDSA signature verification
  x509: Detect sm2 keys by their parameters OID
  x509: Add support for parsing x509 certs with ECDSA keys
  ima: Support EC keys for signature verification

 crypto/Kconfig                            |  10 +
 crypto/Makefile                           |   6 +
 crypto/asymmetric_keys/public_key.c       |   4 +-
 crypto/asymmetric_keys/x509_cert_parser.c |  46 ++-
 crypto/asymmetric_keys/x509_public_key.c  |   4 +-
 crypto/ecc.c                              |  13 +-
 crypto/ecc.h                              |  28 ++
 crypto/ecdsa.c                            | 361 ++++++++++++++++++++++
 crypto/ecdsasignature.asn1                |   4 +
 crypto/testmgr.c                          |  12 +
 crypto/testmgr.h                          | 267 ++++++++++++++++
 include/keys/asymmetric-type.h            |   6 +
 include/linux/oid_registry.h              |   7 +
 lib/oid_registry.c                        |  13 +
 security/integrity/digsig_asymmetric.c    |  30 +-
 15 files changed, 780 insertions(+), 31 deletions(-)
 create mode 100644 crypto/ecdsa.c
 create mode 100644 crypto/ecdsasignature.asn1