crypto: keys - Revert "convert public key to akcipher api"

This needs to go through the security tree so I'm reverting the
patches for now.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/asymmetric_keys/Kconfig

@@ -22,7 +22,7 @@ config ASYMMETRIC_PUBLIC_KEY_SUBTYPE
 
 config PUBLIC_KEY_ALGO_RSA
 	tristate "RSA public-key algorithm"
-	select CRYPTO_RSA
+	select MPILIB
 	help
 	  This option enables support for the RSA algorithm (PKCS#1, RFC3447).
 

crypto/asymmetric_keys/Makefile

@@ -16,18 +16,21 @@ obj-$(CONFIG_X509_CERTIFICATE_PARSER) += x509_key_parser.o
 x509_key_parser-y := \
 	x509-asn1.o \
 	x509_akid-asn1.o \
+	x509_rsakey-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_rsakey-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_rsakey-asn1.o: $(obj)/x509_rsakey-asn1.c $(obj)/x509_rsakey-asn1.h
 
 clean-files	+= x509-asn1.c x509-asn1.h
 clean-files	+= x509_akid-asn1.c x509_akid-asn1.h
+clean-files	+= x509_rsakey-asn1.c x509_rsakey-asn1.h
 
 #
 # PKCS#7 message handling

crypto/asymmetric_keys/pkcs7_parser.c

@@ -15,7 +15,7 @@
 #include <linux/slab.h>
 #include <linux/err.h>
 #include <linux/oid_registry.h>
-#include <crypto/public_key.h>
+#include "public_key.h"
 #include "pkcs7_parser.h"
 #include "pkcs7-asn1.h"
 
@@ -44,7 +44,7 @@ struct pkcs7_parse_context {
 static void pkcs7_free_signed_info(struct pkcs7_signed_info *sinfo)
 {
 	if (sinfo) {
-		kfree(sinfo->sig.s);
+		mpi_free(sinfo->sig.mpi[0]);
 		kfree(sinfo->sig.digest);
 		kfree(sinfo->signing_cert_id);
 		kfree(sinfo);
@@ -614,14 +614,16 @@ int pkcs7_sig_note_signature(void *context, size_t hdrlen,
 			     const void *value, size_t vlen)
 {
 	struct pkcs7_parse_context *ctx = context;
+	MPI mpi;
 
 	BUG_ON(ctx->sinfo->sig.pkey_algo != PKEY_ALGO_RSA);
 
-	ctx->sinfo->sig.s = kmemdup(value, vlen, GFP_KERNEL);
-	if (!ctx->sinfo->sig.s)
+	mpi = mpi_read_raw_data(value, vlen);
+	if (!mpi)
 		return -ENOMEM;
 
-	ctx->sinfo->sig.s_size = vlen;
+	ctx->sinfo->sig.mpi[0] = mpi;
+	ctx->sinfo->sig.nr_mpi = 1;
 	return 0;
 }
 

crypto/asymmetric_keys/pkcs7_trust.c

@@ -17,7 +17,7 @@
 #include <linux/asn1.h>
 #include <linux/key.h>
 #include <keys/asymmetric-type.h>
-#include <crypto/public_key.h>
+#include "public_key.h"
 #include "pkcs7_parser.h"
 
 /**

crypto/asymmetric_keys/pkcs7_verify.c

@@ -16,7 +16,7 @@
 #include <linux/err.h>
 #include <linux/asn1.h>
 #include <crypto/hash.h>
-#include <crypto/public_key.h>
+#include "public_key.h"
 #include "pkcs7_parser.h"
 
 /*

crypto/asymmetric_keys/public_key.c

@@ -18,16 +18,24 @@
 #include <linux/slab.h>
 #include <linux/seq_file.h>
 #include <keys/asymmetric-subtype.h>
-#include <crypto/public_key.h>
+#include "public_key.h"
 
 MODULE_LICENSE("GPL");
 
 const char *const pkey_algo_name[PKEY_ALGO__LAST] = {
-	[PKEY_ALGO_DSA]		= "dsa",
-	[PKEY_ALGO_RSA]		= "rsa",
+	[PKEY_ALGO_DSA]		= "DSA",
+	[PKEY_ALGO_RSA]		= "RSA",
 };
 EXPORT_SYMBOL_GPL(pkey_algo_name);
 
+const struct public_key_algorithm *pkey_algo[PKEY_ALGO__LAST] = {
+#if defined(CONFIG_PUBLIC_KEY_ALGO_RSA) || \
+	defined(CONFIG_PUBLIC_KEY_ALGO_RSA_MODULE)
+	[PKEY_ALGO_RSA]		= &RSA_public_key_algorithm,
+#endif
+};
+EXPORT_SYMBOL_GPL(pkey_algo);
+
 const char *const pkey_id_type_name[PKEY_ID_TYPE__LAST] = {
 	[PKEY_ID_PGP]		= "PGP",
 	[PKEY_ID_X509]		= "X509",
@@ -35,12 +43,6 @@ const char *const pkey_id_type_name[PKEY_ID_TYPE__LAST] = {
 };
 EXPORT_SYMBOL_GPL(pkey_id_type_name);
 
-static int (*alg_verify[PKEY_ALGO__LAST])(const struct public_key *pkey,
-	const struct public_key_signature *sig) = {
-	NULL,
-	rsa_verify_signature
-};
-
 /*
  * Provide a part of a description of the key for /proc/keys.
  */
@@ -51,8 +53,7 @@ static void public_key_describe(const struct key *asymmetric_key,
 
 	if (key)
 		seq_printf(m, "%s.%s",
-			   pkey_id_type_name[key->id_type],
-			   pkey_algo_name[key->pkey_algo]);
+			   pkey_id_type_name[key->id_type], key->algo->name);
 }
 
 /*
@@ -61,31 +62,50 @@ static void public_key_describe(const struct key *asymmetric_key,
 void public_key_destroy(void *payload)
 {
 	struct public_key *key = payload;
+	int i;
 
-	if (key)
-		kfree(key->key);
-	kfree(key);
+	if (key) {
+		for (i = 0; i < ARRAY_SIZE(key->mpi); i++)
+			mpi_free(key->mpi[i]);
+		kfree(key);
+	}
 }
 EXPORT_SYMBOL_GPL(public_key_destroy);
 
 /*
  * Verify a signature using a public key.
  */
-int public_key_verify_signature(const struct public_key *pkey,
+int public_key_verify_signature(const struct public_key *pk,
 				const struct public_key_signature *sig)
 {
-	BUG_ON(!pkey);
+	const struct public_key_algorithm *algo;
+
+	BUG_ON(!pk);
+	BUG_ON(!pk->mpi[0]);
+	BUG_ON(!pk->mpi[1]);
 	BUG_ON(!sig);
 	BUG_ON(!sig->digest);
-	BUG_ON(!sig->s);
+	BUG_ON(!sig->mpi[0]);
+
+	algo = pk->algo;
+	if (!algo) {
+		if (pk->pkey_algo >= PKEY_ALGO__LAST)
+			return -ENOPKG;
+		algo = pkey_algo[pk->pkey_algo];
+		if (!algo)
+			return -ENOPKG;
+	}
 
-	if (pkey->pkey_algo >= PKEY_ALGO__LAST)
-		return -ENOPKG;
+	if (!algo->verify_signature)
+		return -ENOTSUPP;
 
-	if (!alg_verify[pkey->pkey_algo])
-		return -ENOPKG;
+	if (sig->nr_mpi != algo->n_sig_mpi) {
+		pr_debug("Signature has %u MPI not %u\n",
+			 sig->nr_mpi, algo->n_sig_mpi);
+		return -EINVAL;
+	}
 
-	return alg_verify[pkey->pkey_algo](pkey, sig);
+	return algo->verify_signature(pk, sig);
 }
 EXPORT_SYMBOL_GPL(public_key_verify_signature);
 

crypto/asymmetric_keys/public_key.h

+/* Public key algorithm internals
+ *
+ * See Documentation/crypto/asymmetric-keys.txt
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <crypto/public_key.h>
+
+extern struct asymmetric_key_subtype public_key_subtype;
+
+/*
+ * Public key algorithm definition.
+ */
+struct public_key_algorithm {
+	const char	*name;
+	u8		n_pub_mpi;	/* Number of MPIs in public key */
+	u8		n_sec_mpi;	/* Number of MPIs in secret key */
+	u8		n_sig_mpi;	/* Number of MPIs in a signature */
+	int (*verify_signature)(const struct public_key *key,
+				const struct public_key_signature *sig);
+};
+
+extern const struct public_key_algorithm RSA_public_key_algorithm;
+
+/*
+ * public_key.c
+ */
+extern int public_key_verify_signature(const struct public_key *pk,
+				       const struct public_key_signature *sig);

crypto/asymmetric_keys/rsa.c

@@ -11,10 +11,10 @@
 
 #define pr_fmt(fmt) "RSA: "fmt
 #include <linux/module.h>
+#include <linux/kernel.h>
 #include <linux/slab.h>
-#include <crypto/akcipher.h>
-#include <crypto/public_key.h>
 #include <crypto/algapi.h>
+#include "public_key.h"
 
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("RSA Public Key Algorithm");
@@ -84,10 +84,72 @@ static const struct {
 #undef _
 };
 
-struct rsa_completion {
-	struct completion completion;
-	int err;
-};
+/*
+ * RSAVP1() function [RFC3447 sec 5.2.2]
+ */
+static int RSAVP1(const struct public_key *key, MPI s, MPI *_m)
+{
+	MPI m;
+	int ret;
+
+	/* (1) Validate 0 <= s < n */
+	if (mpi_cmp_ui(s, 0) < 0) {
+		kleave(" = -EBADMSG [s < 0]");
+		return -EBADMSG;
+	}
+	if (mpi_cmp(s, key->rsa.n) >= 0) {
+		kleave(" = -EBADMSG [s >= n]");
+		return -EBADMSG;
+	}
+
+	m = mpi_alloc(0);
+	if (!m)
+		return -ENOMEM;
+
+	/* (2) m = s^e mod n */
+	ret = mpi_powm(m, s, key->rsa.e, key->rsa.n);
+	if (ret < 0) {
+		mpi_free(m);
+		return ret;
+	}
+
+	*_m = m;
+	return 0;
+}
+
+/*
+ * Integer to Octet String conversion [RFC3447 sec 4.1]
+ */
+static int RSA_I2OSP(MPI x, size_t xLen, u8 **pX)
+{
+	unsigned X_size, x_size;
+	int X_sign;
+	u8 *X;
+
+	/* Make sure the string is the right length.  The number should begin
+	 * with { 0x00, 0x01, ... } so we have to account for 15 leading zero
+	 * bits not being reported by MPI.
+	 */
+	x_size = mpi_get_nbits(x);
+	pr_devel("size(x)=%u xLen*8=%zu\n", x_size, xLen * 8);
+	if (x_size != xLen * 8 - 15)
+		return -ERANGE;
+
+	X = mpi_get_buffer(x, &X_size, &X_sign);
+	if (!X)
+		return -ENOMEM;
+	if (X_sign < 0) {
+		kfree(X);
+		return -EBADMSG;
+	}
+	if (X_size != xLen - 1) {
+		kfree(X);
+		return -EBADMSG;
+	}
+
+	*pX = X;
+	return 0;
+}
 
 /*
  * Perform the RSA signature verification.
@@ -98,7 +160,7 @@ struct rsa_completion {
  * @asn1_template: The DigestInfo ASN.1 template
  * @asn1_size: Size of asm1_template[]
  */
-static int rsa_verify(const u8 *H, const u8 *EM, size_t k, size_t hash_size,
+static int RSA_verify(const u8 *H, const u8 *EM, size_t k, size_t hash_size,
 		      const u8 *asn1_template, size_t asn1_size)
 {
 	unsigned PS_end, T_offset, i;
@@ -107,10 +169,10 @@ static int rsa_verify(const u8 *H, const u8 *EM, size_t k, size_t hash_size,
 
 	if (k < 2 + 1 + asn1_size + hash_size)
 		return -EBADMSG;
-	/* Decode the EMSA-PKCS1-v1_5
-	 * note: leading zeros are stirpped by the RSA implementation */
-	if (EM[0] != 0x01) {
-		kleave(" = -EBADMSG [EM[0] == %02u]", EM[0]);
+
+	/* Decode the EMSA-PKCS1-v1_5 */
+	if (EM[1] != 0x01) {
+		kleave(" = -EBADMSG [EM[1] == %02u]", EM[1]);
 		return -EBADMSG;
 	}
 
@@ -121,7 +183,7 @@ static int rsa_verify(const u8 *H, const u8 *EM, size_t k, size_t hash_size,
 		return -EBADMSG;
 	}
 
-	for (i = 1; i < PS_end; i++) {
+	for (i = 2; i < PS_end; i++) {
 		if (EM[i] != 0xff) {
 			kleave(" = -EBADMSG [EM[PS%x] == %02u]", i - 2, EM[i]);
 			return -EBADMSG;
@@ -142,82 +204,75 @@ static int rsa_verify(const u8 *H, const u8 *EM, size_t k, size_t hash_size,
 	return 0;
 }
 
-static void public_key_verify_done(struct crypto_async_request *req, int err)
+/*
+ * Perform the verification step [RFC3447 sec 8.2.2].
+ */
+static int RSA_verify_signature(const struct public_key *key,
+				const struct public_key_signature *sig)
 {
-	struct rsa_completion *compl = req->data;
+	size_t tsize;
+	int ret;
 
-	if (err == -EINPROGRESS)
-		return;
+	/* Variables as per RFC3447 sec 8.2.2 */
+	const u8 *H = sig->digest;
+	u8 *EM = NULL;
+	MPI m = NULL;
+	size_t k;
 
-	compl->err = err;
-	complete(&compl->completion);
-}
+	kenter("");
 
-int rsa_verify_signature(const struct public_key *pkey,
-			 const struct public_key_signature *sig)
-{
-	struct crypto_akcipher *tfm;
-	struct akcipher_request *req;
-	struct rsa_completion compl;
-	struct scatterlist sig_sg, sg_out;
-	void *outbuf = NULL;
-	unsigned int outlen = 0;
-	int ret = -ENOMEM;
-
-	tfm = crypto_alloc_akcipher("rsa", 0, 0);
-	if (IS_ERR(tfm))
-		goto error_out;
-
-	req = akcipher_request_alloc(tfm, GFP_KERNEL);
-	if (!req)
-		goto error_free_tfm;
-
-	ret = crypto_akcipher_set_pub_key(tfm, pkey->key, pkey->keylen);
-	if (ret)
-		goto error_free_req;
-
-	ret = -EINVAL;
-	outlen = crypto_akcipher_maxsize(tfm);
-	if (!outlen)
-		goto error_free_req;
-
-	/* initlialzie out buf */
-	ret = -ENOMEM;
-	outbuf = kmalloc(outlen, GFP_KERNEL);
-	if (!outbuf)
-		goto error_free_req;
-
-	sg_init_one(&sig_sg, sig->s, sig->s_size);
-	sg_init_one(&sg_out, outbuf, outlen);
-	akcipher_request_set_crypt(req, &sig_sg, &sg_out, sig->s_size, outlen);
-	init_completion(&compl.completion);
-	akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
-				      CRYPTO_TFM_REQ_MAY_SLEEP,
-				      public_key_verify_done, &compl);
-
-	ret = crypto_akcipher_verify(req);
-	if (ret == -EINPROGRESS) {
-		wait_for_completion(&compl.completion);
-		ret = compl.err;
+	if (!RSA_ASN1_templates[sig->pkey_hash_algo].data)
+		return -ENOTSUPP;
+
+	/* (1) Check the signature size against the public key modulus size */
+	k = mpi_get_nbits(key->rsa.n);
+	tsize = mpi_get_nbits(sig->rsa.s);
+
+	/* According to RFC 4880 sec 3.2, length of MPI is computed starting
+	 * from most significant bit.  So the RFC 3447 sec 8.2.2 size check
+	 * must be relaxed to conform with shorter signatures - so we fail here
+	 * only if signature length is longer than modulus size.
+	 */
+	pr_devel("step 1: k=%zu size(S)=%zu\n", k, tsize);
+	if (k < tsize) {
+		ret = -EBADMSG;
+		goto error;
 	}
 
-	if (ret)
-		goto error_free_req;
+	/* Round up and convert to octets */
+	k = (k + 7) / 8;
 
-	/*
-	 * Output from the operation is an encoded message (EM) of
-	 * length k octets.
+	/* (2b) Apply the RSAVP1 verification primitive to the public key */
+	ret = RSAVP1(key, sig->rsa.s, &m);
+	if (ret < 0)
+		goto error;
+
+	/* (2c) Convert the message representative (m) to an encoded message
+	 *      (EM) of length k octets.
+	 *
+	 *      NOTE!  The leading zero byte is suppressed by MPI, so we pass a
+	 *      pointer to the _preceding_ byte to RSA_verify()!
 	 */
-	outlen = req->dst_len;
-	ret = rsa_verify(sig->digest, outbuf, outlen, sig->digest_size,
+	ret = RSA_I2OSP(m, k, &EM);
+	if (ret < 0)
+		goto error;
+
+	ret = RSA_verify(H, EM - 1, k, sig->digest_size,
 			 RSA_ASN1_templates[sig->pkey_hash_algo].data,
 			 RSA_ASN1_templates[sig->pkey_hash_algo].size);
-error_free_req:
-	akcipher_request_free(req);
-error_free_tfm:
-	crypto_free_akcipher(tfm);
-error_out:
-	kfree(outbuf);
+
+error:
+	kfree(EM);
+	mpi_free(m);
+	kleave(" = %d", ret);
 	return ret;
 }
-EXPORT_SYMBOL_GPL(rsa_verify_signature);
+
+const struct public_key_algorithm RSA_public_key_algorithm = {
+	.name		= "RSA",
+	.n_pub_mpi	= 2,
+	.n_sec_mpi	= 3,
+	.n_sig_mpi	= 1,
+	.verify_signature = RSA_verify_signature,
+};
+EXPORT_SYMBOL_GPL(RSA_public_key_algorithm);

crypto/asymmetric_keys/x509_cert_parser.c

@@ -15,10 +15,11 @@
 #include <linux/slab.h>
 #include <linux/err.h>
 #include <linux/oid_registry.h>
-#include <crypto/public_key.h>
+#include "public_key.h"
 #include "x509_parser.h"
 #include "x509-asn1.h"
 #include "x509_akid-asn1.h"
+#include "x509_rsakey-asn1.h"
 
 struct x509_parse_context {
 	struct x509_certificate	*cert;		/* Certificate being constructed */
@@ -55,7 +56,7 @@ void x509_free_certificate(struct x509_certificate *cert)
 		kfree(cert->akid_id);
 		kfree(cert->akid_skid);
 		kfree(cert->sig.digest);
-		kfree(cert->sig.s);
+		mpi_free(cert->sig.rsa.s);
 		kfree(cert);
 	}
 }
@@ -102,12 +103,12 @@ struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
 		}
 	}
 
-	cert->pub->key = kmemdup(ctx->key, ctx->key_size, GFP_KERNEL);
-	if (!cert->pub->key)
+	/* Decode the public key */
+	ret = asn1_ber_decoder(&x509_rsakey_decoder, ctx,
+			       ctx->key, ctx->key_size);
+	if (ret < 0)
 		goto error_decode;
 
-	cert->pub->keylen = ctx->key_size;
-
 	/* Generate cert issuer + serial number key ID */
 	kid = asymmetric_key_generate_id(cert->raw_serial,
 					 cert->raw_serial_size,
@@ -123,7 +124,6 @@ struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
 	return cert;
 
 error_decode:
-	kfree(cert->pub->key);
 	kfree(ctx);
 error_no_ctx:
 	x509_free_certificate(cert);
@@ -404,6 +404,29 @@ int x509_extract_key_data(void *context, size_t hdrlen,
 	return 0;
 }
 
+/*
+ * Extract a RSA public key value
+ */
+int rsa_extract_mpi(void *context, size_t hdrlen,
+		    unsigned char tag,
+		    const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+	MPI mpi;
+
+	if (ctx->nr_mpi >= ARRAY_SIZE(ctx->cert->pub->mpi)) {
+		pr_err("Too many public key MPIs in certificate\n");
+		return -EBADMSG;
+	}
+
+	mpi = mpi_read_raw_data(value, vlen);
+	if (!mpi)
+		return -ENOMEM;
+
+	ctx->cert->pub->mpi[ctx->nr_mpi++] = mpi;
+	return 0;
+}
+
 /* The keyIdentifier in AuthorityKeyIdentifier SEQUENCE is tag(CONT,PRIM,0) */
 #define SEQ_TAG_KEYID (ASN1_CONT << 6)
 

crypto/asymmetric_keys/x509_public_key.c

@@ -13,11 +13,15 @@
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/mpi.h>
+#include <linux/asn1_decoder.h>
 #include <keys/asymmetric-subtype.h>
 #include <keys/asymmetric-parser.h>
 #include <keys/system_keyring.h>
 #include <crypto/hash.h>
 #include "asymmetric_keys.h"
+#include "public_key.h"
 #include "x509_parser.h"
 
 static bool use_builtin_keys;
@@ -163,15 +167,13 @@ int x509_get_sig_params(struct x509_certificate *cert)
 
 	if (cert->unsupported_crypto)
 		return -ENOPKG;
-	if (cert->sig.s)
+	if (cert->sig.rsa.s)
 		return 0;
 
-	cert->sig.s = kmemdup(cert->raw_sig, cert->raw_sig_size,
-			      GFP_KERNEL);
-	if (!cert->sig.s)
+	cert->sig.rsa.s = mpi_read_raw_data(cert->raw_sig, cert->raw_sig_size);
+	if (!cert->sig.rsa.s)
 		return -ENOMEM;
-
-	cert->sig.s_size = cert->raw_sig_size;
+	cert->sig.nr_mpi = 1;
 
 	/* Allocate the hashing algorithm we're going to need and find out how
 	 * big the hash operational data will be.
@@ -294,6 +296,8 @@ static int x509_key_preparse(struct key_preparsed_payload *prep)
 	if (cert->pub->pkey_algo >= PKEY_ALGO__LAST ||
 	    cert->sig.pkey_algo >= PKEY_ALGO__LAST ||
 	    cert->sig.pkey_hash_algo >= PKEY_HASH__LAST ||
+	    !pkey_algo[cert->pub->pkey_algo] ||
+	    !pkey_algo[cert->sig.pkey_algo] ||
 	    !hash_algo_name[cert->sig.pkey_hash_algo]) {
 		ret = -ENOPKG;
 		goto error_free_cert;
@@ -305,6 +309,7 @@ static int x509_key_preparse(struct key_preparsed_payload *prep)
 		 pkey_algo_name[cert->sig.pkey_algo],
 		 hash_algo_name[cert->sig.pkey_hash_algo]);
 
+	cert->pub->algo = pkey_algo[cert->pub->pkey_algo];
 	cert->pub->id_type = PKEY_ID_X509;
 
 	/* Check the signature on the key if it appears to be self-signed */

crypto/asymmetric_keys/x509_rsakey.asn1

+RSAPublicKey ::= SEQUENCE {
+	modulus			INTEGER ({ rsa_extract_mpi }),	-- n
+	publicExponent		INTEGER ({ rsa_extract_mpi })	-- e
+	}

include/crypto/public_key.h

@@ -14,6 +14,7 @@
 #ifndef _LINUX_PUBLIC_KEY_H
 #define _LINUX_PUBLIC_KEY_H
 
+#include <linux/mpi.h>
 #include <crypto/hash_info.h>
 
 enum pkey_algo {
@@ -23,6 +24,7 @@ enum pkey_algo {
 };
 
 extern const char *const pkey_algo_name[PKEY_ALGO__LAST];
+extern const struct public_key_algorithm *pkey_algo[PKEY_ALGO__LAST];
 
 /* asymmetric key implementation supports only up to SHA224 */
 #define PKEY_HASH__LAST		(HASH_ALGO_SHA224 + 1)
@@ -57,10 +59,31 @@ extern const char *const key_being_used_for[NR__KEY_BEING_USED_FOR];
  * part.
  */
 struct public_key {
-	void *key;
-	u32 keylen;
+	const struct public_key_algorithm *algo;
+	u8	capabilities;
+#define PKEY_CAN_ENCRYPT	0x01
+#define PKEY_CAN_DECRYPT	0x02
+#define PKEY_CAN_SIGN		0x04
+#define PKEY_CAN_VERIFY		0x08
 	enum pkey_algo pkey_algo : 8;
 	enum pkey_id_type id_type : 8;
+	union {
+		MPI	mpi[5];
+		struct {
+			MPI	p;	/* DSA prime */
+			MPI	q;	/* DSA group order */
+			MPI	g;	/* DSA group generator */
+			MPI	y;	/* DSA public-key value = g^x mod p */
+			MPI	x;	/* DSA secret exponent (if present) */
+		} dsa;
+		struct {
+			MPI	n;	/* RSA public modulus */
+			MPI	e;	/* RSA public encryption exponent */
+			MPI	d;	/* RSA secret encryption exponent (if present) */
+			MPI	p;	/* RSA secret prime (if present) */
+			MPI	q;	/* RSA secret prime (if present) */
+		} rsa;
+	};
 };
 
 extern void public_key_destroy(void *payload);
@@ -69,15 +92,23 @@ extern void public_key_destroy(void *payload);
  * Public key cryptography signature data
  */
 struct public_key_signature {
-	u8 *s;			/* Signature */
-	u32 s_size;		/* Number of bytes in signature */
 	u8 *digest;
-	u8 digest_size;		/* Number of bytes in digest */
+	u8 digest_size;			/* Number of bytes in digest */
+	u8 nr_mpi;			/* Occupancy of mpi[] */
 	enum pkey_algo pkey_algo : 8;
 	enum hash_algo pkey_hash_algo : 8;
+	union {
+		MPI mpi[2];
+		struct {
+			MPI s;		/* m^d mod n */
+		} rsa;
+		struct {
+			MPI r;
+			MPI s;
+		} dsa;
+	};
 };
 
-extern struct asymmetric_key_subtype public_key_subtype;
 struct key;
 extern int verify_signature(const struct key *key,
 			    const struct public_key_signature *sig);
@@ -88,9 +119,4 @@ extern struct key *x509_request_asymmetric_key(struct key *keyring,
 					       const struct asymmetric_key_id *skid,
 					       bool partial);
 
-int public_key_verify_signature(const struct public_key *pkey,
-				const struct public_key_signature *sig);
-
-int rsa_verify_signature(const struct public_key *pkey,
-			 const struct public_key_signature *sig);
 #endif /* _LINUX_PUBLIC_KEY_H */

security/integrity/Kconfig

@@ -36,7 +36,6 @@ config INTEGRITY_ASYMMETRIC_KEYS
         select ASYMMETRIC_KEY_TYPE
         select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
         select PUBLIC_KEY_ALGO_RSA
-        select CRYPTO_RSA
         select X509_CERTIFICATE_PARSER
 	help
 	  This option enables digital signature verification using

security/integrity/digsig_asymmetric.c

@@ -106,9 +106,13 @@ int asymmetric_verify(struct key *keyring, const char *sig,
 	pks.pkey_hash_algo = hdr->hash_algo;
 	pks.digest = (u8 *)data;
 	pks.digest_size = datalen;
-	pks.s = hdr->sig;
-	pks.s_size = siglen;
-	ret = verify_signature(key, &pks);
+	pks.nr_mpi = 1;
+	pks.rsa.s = mpi_read_raw_data(hdr->sig, siglen);
+
+	if (pks.rsa.s)
+		ret = verify_signature(key, &pks);
+
+	mpi_free(pks.rsa.s);
 	key_put(key);
 	pr_debug("%s() = %d\n", __func__, ret);
 	return ret;