lib: crypto: add rsa public key parser

Imported from linux kernel v5.3:
rsapubkey.asn1 without changes
rsa.h without changes
rsa_helper.c with changes marked as __UBOOT__

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

lib/crypto/Kconfig

@@ -16,4 +16,15 @@ config ASYMMETRIC_PUBLIC_KEY_SUBTYPE
 	  appropriate hash algorithms (such as SHA-1) must be available.
 	  ENOPKG will be reported if the requisite algorithm is unavailable.
 
+config RSA_PUBLIC_KEY_PARSER
+	bool "RSA public key parser"
+	depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE
+	select ASN1_DECODER
+	select ASN1_COMPILER
+	select OID_REGISTRY
+	help
+	  This option provides support for parsing a blob containing RSA
+	  public key data and provides the ability to instantiate a public
+	  key.
+
 endif # ASYMMETRIC_KEY_TYPE

lib/crypto/Makefile

@@ -8,3 +8,14 @@ obj-$(CONFIG_ASYMMETRIC_KEY_TYPE) += asymmetric_keys.o
 asymmetric_keys-y := asymmetric_type.o
 
 obj-$(CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE) += public_key.o
+
+#
+# RSA public key parser
+#
+obj-$(CONFIG_RSA_PUBLIC_KEY_PARSER) += rsa_public_key.o
+rsa_public_key-y := \
+	rsapubkey.asn1.o \
+	rsa_helper.o
+
+$(obj)/rsapubkey.asn1.o: $(obj)/rsapubkey.asn1.c $(obj)/rsapubkey.asn1.h
+$(obj)/rsa_helper.o: $(obj)/rsapubkey.asn1.h

lib/crypto/rsa_helper.c

@@ -0,0 +1,198 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * RSA key extract helper
+ *
+ * Copyright (c) 2015, Intel Corporation
+ * Authors: Tadeusz Struk <tadeusz.struk@intel.com>
+ */
+#ifndef __UBOOT__
+#include <linux/kernel.h>
+#include <linux/export.h>
+#endif
+#include <linux/err.h>
+#ifndef __UBOOT__
+#include <linux/fips.h>
+#endif
+#include <crypto/internal/rsa.h>
+#include "rsapubkey.asn1.h"
+#ifndef __UBOOT__
+#include "rsaprivkey.asn1.h"
+#endif
+
+int rsa_get_n(void *context, size_t hdrlen, unsigned char tag,
+	      const void *value, size_t vlen)
+{
+	struct rsa_key *key = context;
+#ifndef __UBOOT__
+	const u8 *ptr = value;
+	size_t n_sz = vlen;
+#endif
+
+	/* invalid key provided */
+	if (!value || !vlen)
+		return -EINVAL;
+
+#ifndef __UBOOT__
+	if (fips_enabled) {
+		while (n_sz && !*ptr) {
+			ptr++;
+			n_sz--;
+		}
+
+		/* In FIPS mode only allow key size 2K and higher */
+		if (n_sz < 256) {
+			pr_err("RSA: key size not allowed in FIPS mode\n");
+			return -EINVAL;
+		}
+	}
+#endif
+
+	key->n = value;
+	key->n_sz = vlen;
+
+	return 0;
+}
+
+int rsa_get_e(void *context, size_t hdrlen, unsigned char tag,
+	      const void *value, size_t vlen)
+{
+	struct rsa_key *key = context;
+
+	/* invalid key provided */
+	if (!value || !key->n_sz || !vlen || vlen > key->n_sz)
+		return -EINVAL;
+
+	key->e = value;
+	key->e_sz = vlen;
+
+	return 0;
+}
+
+int rsa_get_d(void *context, size_t hdrlen, unsigned char tag,
+	      const void *value, size_t vlen)
+{
+	struct rsa_key *key = context;
+
+	/* invalid key provided */
+	if (!value || !key->n_sz || !vlen || vlen > key->n_sz)
+		return -EINVAL;
+
+	key->d = value;
+	key->d_sz = vlen;
+
+	return 0;
+}
+
+int rsa_get_p(void *context, size_t hdrlen, unsigned char tag,
+	      const void *value, size_t vlen)
+{
+	struct rsa_key *key = context;
+
+	/* invalid key provided */
+	if (!value || !vlen || vlen > key->n_sz)
+		return -EINVAL;
+
+	key->p = value;
+	key->p_sz = vlen;
+
+	return 0;
+}
+
+int rsa_get_q(void *context, size_t hdrlen, unsigned char tag,
+	      const void *value, size_t vlen)
+{
+	struct rsa_key *key = context;
+
+	/* invalid key provided */
+	if (!value || !vlen || vlen > key->n_sz)
+		return -EINVAL;
+
+	key->q = value;
+	key->q_sz = vlen;
+
+	return 0;
+}
+
+int rsa_get_dp(void *context, size_t hdrlen, unsigned char tag,
+	       const void *value, size_t vlen)
+{
+	struct rsa_key *key = context;
+
+	/* invalid key provided */
+	if (!value || !vlen || vlen > key->n_sz)
+		return -EINVAL;
+
+	key->dp = value;
+	key->dp_sz = vlen;
+
+	return 0;
+}
+
+int rsa_get_dq(void *context, size_t hdrlen, unsigned char tag,
+	       const void *value, size_t vlen)
+{
+	struct rsa_key *key = context;
+
+	/* invalid key provided */
+	if (!value || !vlen || vlen > key->n_sz)
+		return -EINVAL;
+
+	key->dq = value;
+	key->dq_sz = vlen;
+
+	return 0;
+}
+
+int rsa_get_qinv(void *context, size_t hdrlen, unsigned char tag,
+		 const void *value, size_t vlen)
+{
+	struct rsa_key *key = context;
+
+	/* invalid key provided */
+	if (!value || !vlen || vlen > key->n_sz)
+		return -EINVAL;
+
+	key->qinv = value;
+	key->qinv_sz = vlen;
+
+	return 0;
+}
+
+/**
+ * rsa_parse_pub_key() - decodes the BER encoded buffer and stores in the
+ *                       provided struct rsa_key, pointers to the raw key as is,
+ *                       so that the caller can copy it or MPI parse it, etc.
+ *
+ * @rsa_key:	struct rsa_key key representation
+ * @key:	key in BER format
+ * @key_len:	length of key
+ *
+ * Return:	0 on success or error code in case of error
+ */
+int rsa_parse_pub_key(struct rsa_key *rsa_key, const void *key,
+		      unsigned int key_len)
+{
+	return asn1_ber_decoder(&rsapubkey_decoder, rsa_key, key, key_len);
+}
+EXPORT_SYMBOL_GPL(rsa_parse_pub_key);
+
+#ifndef __UBOOT__
+/**
+ * rsa_parse_priv_key() - decodes the BER encoded buffer and stores in the
+ *                        provided struct rsa_key, pointers to the raw key
+ *                        as is, so that the caller can copy it or MPI parse it,
+ *                        etc.
+ *
+ * @rsa_key:	struct rsa_key key representation
+ * @key:	key in BER format
+ * @key_len:	length of key
+ *
+ * Return:	0 on success or error code in case of error
+ */
+int rsa_parse_priv_key(struct rsa_key *rsa_key, const void *key,
+		       unsigned int key_len)
+{
+	return asn1_ber_decoder(&rsaprivkey_decoder, rsa_key, key, key_len);
+}
+EXPORT_SYMBOL_GPL(rsa_parse_priv_key);
+#endif

lib/crypto/rsapubkey.asn1

@@ -0,0 +1,4 @@
+RsaPubKey ::= SEQUENCE {
+	n INTEGER ({ rsa_get_n }),
+	e INTEGER ({ rsa_get_e })
+}