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From:   Hongbo Li <herbert.tencent@gmail.com>
To:     keyrings@vger.kernel.org, linux-crypto@vger.kernel.org,
        herbert@gondor.apana.org.au, dhowells@redhat.com,
        zohar@linux.ibm.com, jarkko@kernel.org, herberthbli@tencent.com
Cc:     linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org
Subject: [PATCH 1/5] x509: add support for rsa-pss
Date:   Tue,  6 Apr 2021 21:11:22 +0800
Message-Id: <1617714686-25754-2-git-send-email-herbert.tencent@gmail.com>
In-Reply-To: <1617714686-25754-1-git-send-email-herbert.tencent@gmail.com>
References: <1617714686-25754-1-git-send-email-herbert.tencent@gmail.com>
Precedence: bulk

From: Hongbo Li <herberthbli@tencent.com>

This patch make x509 support rsa-pss, because the sha algo is
in signature, so we need to parse the sha parameter, and skip
other params.

Signed-off-by: Hongbo Li <herberthbli@tencent.com>
---
 crypto/asymmetric_keys/Makefile           |  7 ++-
 crypto/asymmetric_keys/public_key.c       |  5 +++
 crypto/asymmetric_keys/x509_cert_parser.c | 71 +++++++++++++++++++++++++++++--
 include/linux/oid_registry.h              |  2 +
 4 files changed, 80 insertions(+), 5 deletions(-)

diff --git a/crypto/asymmetric_keys/Makefile b/crypto/asymmetric_keys/Makefile
index 28b91ad..9092de7 100644
--- a/crypto/asymmetric_keys/Makefile
+++ b/crypto/asymmetric_keys/Makefile
@@ -20,15 +20,20 @@ obj-$(CONFIG_X509_CERTIFICATE_PARSER) += x509_key_parser.o
 x509_key_parser-y := \
 	x509.asn1.o \
 	x509_akid.asn1.o \
+	x509_rsapss_params.asn1.o \
 	x509_cert_parser.o \
 	x509_public_key.o
 
 $(obj)/x509_cert_parser.o: \
 	$(obj)/x509.asn1.h \
-	$(obj)/x509_akid.asn1.h
+	$(obj)/x509_akid.asn1.h \
+	$(obj)/x509_rsapss_params.asn1.h
+
 
 $(obj)/x509.asn1.o: $(obj)/x509.asn1.c $(obj)/x509.asn1.h
 $(obj)/x509_akid.asn1.o: $(obj)/x509_akid.asn1.c $(obj)/x509_akid.asn1.h
+$(obj)/x509_rsapss_params.asn1.o: \
+	$(obj)/x509_rsapss_params.asn1.c $(obj)/x509_rsapss_params.asn1.h
 
 #
 # PKCS#8 private key handling
diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c
index 788a4ba..cf049fd 100644
--- a/crypto/asymmetric_keys/public_key.c
+++ b/crypto/asymmetric_keys/public_key.c
@@ -83,6 +83,11 @@ int software_key_determine_akcipher(const char *encoding,
 				     "pkcs1pad(%s,%s)",
 				     pkey->pkey_algo, hash_algo);
 		return n >= CRYPTO_MAX_ALG_NAME ? -EINVAL : 0;
+	} else if (strcmp(encoding, "pss") == 0) {
+		n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME,
+			     "psspad(%s)",
+			     pkey->pkey_algo);
+		return n >= CRYPTO_MAX_ALG_NAME ? -EINVAL : 0;
 	}
 
 	if (strcmp(encoding, "raw") == 0) {
diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index 52c9b45..ec3428d 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c
@@ -15,6 +15,7 @@
 #include "x509_parser.h"
 #include "x509.asn1.h"
 #include "x509_akid.asn1.h"
+#include "x509_rsapss_params.asn1.h"
 
 struct x509_parse_context {
 	struct x509_certificate	*cert;		/* Certificate being constructed */
@@ -115,6 +116,17 @@ struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
 	cert->pub->paramlen = ctx->params_size;
 	cert->pub->algo = ctx->key_algo;
 
+	if (!strcmp(cert->sig->pkey_algo, "rsa") &&
+	    !strcmp(cert->sig->encoding, "pss") &&
+	    cert->pub->paramlen) {
+		ret = asn1_ber_decoder(&x509_rsapss_params_decoder, ctx,
+				       cert->pub->params, cert->pub->paramlen);
+		if (ret < 0) {
+			pr_warn("Couldn't decode rsapss params\n");
+			goto error_decode;
+		}
+	}
+
 	/* Grab the signature bits */
 	ret = x509_get_sig_params(cert);
 	if (ret < 0)
@@ -211,6 +223,10 @@ int x509_note_pkey_algo(void *context, size_t hdrlen,
 		ctx->cert->sig->hash_algo = "sha1";
 		goto rsa_pkcs1;
 
+	case OID_rsa_pss:
+		ctx->cert->sig->hash_algo = "sha1";
+		goto rsa_pss;
+
 	case OID_sha256WithRSAEncryption:
 		ctx->cert->sig->hash_algo = "sha256";
 		goto rsa_pkcs1;
@@ -245,6 +261,11 @@ int x509_note_pkey_algo(void *context, size_t hdrlen,
 	ctx->cert->sig->encoding = "pkcs1";
 	ctx->algo_oid = ctx->last_oid;
 	return 0;
+rsa_pss:
+	ctx->cert->sig->pkey_algo = "rsa";
+	ctx->cert->sig->encoding = "pss";
+	ctx->algo_oid = ctx->last_oid;
+	return 0;
 ecrdsa:
 	ctx->cert->sig->pkey_algo = "ecrdsa";
 	ctx->cert->sig->encoding = "raw";
@@ -440,17 +461,59 @@ int x509_note_params(void *context, size_t hdrlen,
 	struct x509_parse_context *ctx = context;
 
 	/*
-	 * AlgorithmIdentifier is used three times in the x509, we should skip
-	 * first and ignore third, using second one which is after subject and
-	 * before subjectPublicKey.
+	 * AlgorithmIdentifier is used three times in the x509,
+	 * rsapss:
+	 * we skip first(same as third) and second(may omit params).
+	 * others:
+	 * we should skip first and ignore third, using second one
+	 * which is after subject and before subjectPublicKey.
 	 */
-	if (!ctx->cert->raw_subject || ctx->key)
+	if (!ctx->cert->raw_subject) {
+		return 0;
+	} else if (strcmp(ctx->cert->sig->pkey_algo, "rsa") ||
+		   strcmp(ctx->cert->sig->encoding, "pss")) {
+		if (ctx->key)
+			return 0;
+	} else if (!ctx->key) {
 		return 0;
+	}
+
 	ctx->params = value - hdrlen;
 	ctx->params_size = vlen + hdrlen;
 	return 0;
 }
 
+int x509_note_rsapss_hash(void *context, size_t hdrlen,
+			  unsigned char tag,
+			  const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+	enum OID oid;
+
+	oid = look_up_OID(value, vlen);
+	switch (oid) {
+	case OID_sha1:
+		ctx->cert->sig->hash_algo = "sha1";
+		break;
+	case OID_sha224:
+		ctx->cert->sig->hash_algo = "sha224";
+		break;
+	case OID_sha256:
+		ctx->cert->sig->hash_algo = "sha256";
+		break;
+	case OID_sha384:
+		ctx->cert->sig->hash_algo = "sha384";
+		break;
+	case OID_sha512:
+		ctx->cert->sig->hash_algo = "sha512";
+		break;
+	default:
+		return -ENOPKG;
+	}
+
+	return 0;
+}
+
 /*
  * Extract the data for the public key algorithm
  */
diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h
index 4462ed2..bb22b84 100644
--- a/include/linux/oid_registry.h
+++ b/include/linux/oid_registry.h
@@ -28,6 +28,8 @@ enum OID {
 	OID_md3WithRSAEncryption,	/* 1.2.840.113549.1.1.3 */
 	OID_md4WithRSAEncryption,	/* 1.2.840.113549.1.1.4 */
 	OID_sha1WithRSAEncryption,	/* 1.2.840.113549.1.1.5 */
+	OID_rsa_mgf1,			/* 1.2.840.113549.1.1.8 */
+	OID_rsa_pss,			/* 1.2.840.113549.1.1.10 */
 	OID_sha256WithRSAEncryption,	/* 1.2.840.113549.1.1.11 */
 	OID_sha384WithRSAEncryption,	/* 1.2.840.113549.1.1.12 */
 	OID_sha512WithRSAEncryption,	/* 1.2.840.113549.1.1.13 */
-- 
1.8.3.1