From 947d70597236dd5ae65c1f68c8eabfb962ee5a6b Mon Sep 17 00:00:00 2001 From: Stefan Berger Date: Tue, 16 Mar 2021 17:07:38 -0400 Subject: [PATCH] ima: Support EC keys for signature verification Add support for IMA signature verification for EC keys. Since SHA type of hashes can be used by RSA and ECDSA signature schemes we need to look at the key and derive from the key which signature scheme to use. Since this can be applied to all types of keys, we change the selection of the encoding type to be driven by the key's signature scheme rather than by the hash type. Cc: Dmitry Kasatkin Cc: linux-integrity@vger.kernel.org Cc: David Howells Cc: keyrings@vger.kernel.org Signed-off-by: Stefan Berger Reviewed-by: Vitaly Chikunov Reviewed-by: Tianjia Zhang Acked-by: Mimi Zohar Signed-off-by: Herbert Xu --- include/keys/asymmetric-type.h | 6 ++++++ security/integrity/digsig_asymmetric.c | 30 ++++++++++++++---------------- 2 files changed, 20 insertions(+), 16 deletions(-) diff --git a/include/keys/asymmetric-type.h b/include/keys/asymmetric-type.h index a29d3ff..c432fdb8 100644 --- a/include/keys/asymmetric-type.h +++ b/include/keys/asymmetric-type.h @@ -72,6 +72,12 @@ const struct asymmetric_key_ids *asymmetric_key_ids(const struct key *key) return key->payload.data[asym_key_ids]; } +static inline +const struct public_key *asymmetric_key_public_key(const struct key *key) +{ + return key->payload.data[asym_crypto]; +} + extern struct key *find_asymmetric_key(struct key *keyring, const struct asymmetric_key_id *id_0, const struct asymmetric_key_id *id_1, diff --git a/security/integrity/digsig_asymmetric.c b/security/integrity/digsig_asymmetric.c index a662024b..23240d7 100644 --- a/security/integrity/digsig_asymmetric.c +++ b/security/integrity/digsig_asymmetric.c @@ -84,6 +84,7 @@ int asymmetric_verify(struct key *keyring, const char *sig, { struct public_key_signature pks; struct signature_v2_hdr *hdr = (struct signature_v2_hdr *)sig; + const struct public_key *pk; struct key *key; int ret; @@ -105,23 +106,20 @@ int asymmetric_verify(struct key *keyring, const char *sig, memset(&pks, 0, sizeof(pks)); pks.hash_algo = hash_algo_name[hdr->hash_algo]; - switch (hdr->hash_algo) { - case HASH_ALGO_STREEBOG_256: - case HASH_ALGO_STREEBOG_512: - /* EC-RDSA and Streebog should go together. */ - pks.pkey_algo = "ecrdsa"; - pks.encoding = "raw"; - break; - case HASH_ALGO_SM3_256: - /* SM2 and SM3 should go together. */ - pks.pkey_algo = "sm2"; - pks.encoding = "raw"; - break; - default: - pks.pkey_algo = "rsa"; + + pk = asymmetric_key_public_key(key); + pks.pkey_algo = pk->pkey_algo; + if (!strcmp(pk->pkey_algo, "rsa")) pks.encoding = "pkcs1"; - break; - } + else if (!strncmp(pk->pkey_algo, "ecdsa-", 6)) + /* edcsa-nist-p192 etc. */ + pks.encoding = "x962"; + else if (!strcmp(pk->pkey_algo, "ecrdsa") || + !strcmp(pk->pkey_algo, "sm2")) + pks.encoding = "raw"; + else + return -ENOPKG; + pks.digest = (u8 *)data; pks.digest_size = datalen; pks.s = hdr->sig; -- 2.7.4