crypto: rsa - add a new rsa generic implementation

Add a new rsa generic SW implementation.
This implements only cryptographic primitives.

Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>

Added select on ASN1.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 121 insertions, 0 deletions

diff --git a/crypto/rsa_helper.c b/crypto/rsa_helper.c
new file mode 100644
index 000000000000..3e8e0a9e5a8e
--- /dev/null
+++ b/crypto/rsa_helper.c
@@ -0,0 +1,121 @@
+/*
+ * RSA key extract helper
+ *
+ * Copyright (c) 2015, Intel Corporation
+ * Authors: Tadeusz Struk <tadeusz.struk@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/err.h>
+#include <linux/fips.h>
+#include <crypto/internal/rsa.h>
+#include "rsakey-asn1.h"
+
+int rsa_get_n(void *context, size_t hdrlen, unsigned char tag,
+              const void *value, size_t vlen)
+{
+        struct rsa_key *key = context;
+
+        key->n = mpi_read_raw_data(value, vlen);
+
+        if (!key->n)
+                return -ENOMEM;
+
+        /* In FIPS mode only allow key size 2K & 3K */
+        if (fips_enabled && (mpi_get_size(key->n) != 256 ||
+                             mpi_get_size(key->n) != 384)) {
+                pr_err("RSA: key size not allowed in FIPS mode\n");
+                mpi_free(key->n);
+                key->n = NULL;
+                return -EINVAL;
+        }
+        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;
+
+        key->e = mpi_read_raw_data(value, vlen);
+
+        if (!key->e)
+                return -ENOMEM;
+
+        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;
+
+        key->d = mpi_read_raw_data(value, vlen);
+
+        if (!key->d)
+                return -ENOMEM;
+
+        /* In FIPS mode only allow key size 2K & 3K */
+        if (fips_enabled && (mpi_get_size(key->d) != 256 ||
+                             mpi_get_size(key->d) != 384)) {
+                pr_err("RSA: key size not allowed in FIPS mode\n");
+                mpi_free(key->d);
+                key->d = NULL;
+                return -EINVAL;
+        }
+        return 0;
+}
+
+static void free_mpis(struct rsa_key *key)
+{
+        mpi_free(key->n);
+        mpi_free(key->e);
+        mpi_free(key->d);
+        key->n = NULL;
+        key->e = NULL;
+        key->d = NULL;
+}
+
+/**
+ * rsa_free_key() - frees rsa key allocated by rsa_parse_key()
+ *
+ * @rsa_key:    struct rsa_key key representation
+ */
+void rsa_free_key(struct rsa_key *key)
+{
+        free_mpis(key);
+}
+EXPORT_SYMBOL_GPL(rsa_free_key);
+
+/**
+ * rsa_parse_key() - extracts an rsa key from BER encoded buffer
+ *                   and stores it in the provided struct rsa_key
+ *
+ * @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_key(struct rsa_key *rsa_key, const void *key,
+                  unsigned int key_len)
+{
+        int ret;
+
+        free_mpis(rsa_key);
+        ret = asn1_ber_decoder(&rsakey_decoder, rsa_key, key, key_len);
+        if (ret < 0)
+                goto error;
+
+        return 0;
+error:
+        free_mpis(rsa_key);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(rsa_parse_key);