crypto: rsa - return raw integers for the ASN.1 parser

Return the raw key with no other processing so that the caller
can copy it or MPI parse it, etc.

The scope is to have only one ANS.1 parser for all RSA
implementations.

Update the RSA software implementation so that it does
the MPI conversion on top.

Signed-off-by: Tudor Ambarus <tudor-dan.ambarus@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 80 insertions, 25 deletions

diff --git a/crypto/rsa.c b/crypto/rsa.c
index 77d737f52147..dc692d43b666 100644
--- a/crypto/rsa.c
+++ b/crypto/rsa.c
@@ -10,16 +10,23 @@
  */
 
 #include <linux/module.h>
+#include <linux/mpi.h>
 #include <crypto/internal/rsa.h>
 #include <crypto/internal/akcipher.h>
 #include <crypto/akcipher.h>
 #include <crypto/algapi.h>
 
+struct rsa_mpi_key {
+	MPI n;
+	MPI e;
+	MPI d;
+};
+
 /*
  * RSAEP function [RFC3447 sec 5.1.1]
  * c = m^e mod n;
  */
-static int _rsa_enc(const struct rsa_key *key, MPI c, MPI m)
+static int _rsa_enc(const struct rsa_mpi_key *key, MPI c, MPI m)
 {
 	/* (1) Validate 0 <= m < n */
 	if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)
@@ -33,7 +40,7 @@ static int _rsa_enc(const struct rsa_key *key, MPI c, MPI m)
  * RSADP function [RFC3447 sec 5.1.2]
  * m = c^d mod n;
  */
-static int _rsa_dec(const struct rsa_key *key, MPI m, MPI c)
+static int _rsa_dec(const struct rsa_mpi_key *key, MPI m, MPI c)
 {
 	/* (1) Validate 0 <= c < n */
 	if (mpi_cmp_ui(c, 0) < 0 || mpi_cmp(c, key->n) >= 0)
@@ -47,7 +54,7 @@ static int _rsa_dec(const struct rsa_key *key, MPI m, MPI c)
  * RSASP1 function [RFC3447 sec 5.2.1]
  * s = m^d mod n
  */
-static int _rsa_sign(const struct rsa_key *key, MPI s, MPI m)
+static int _rsa_sign(const struct rsa_mpi_key *key, MPI s, MPI m)
 {
 	/* (1) Validate 0 <= m < n */
 	if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)
@@ -61,7 +68,7 @@ static int _rsa_sign(const struct rsa_key *key, MPI s, MPI m)
  * RSAVP1 function [RFC3447 sec 5.2.2]
  * m = s^e mod n;
  */
-static int _rsa_verify(const struct rsa_key *key, MPI m, MPI s)
+static int _rsa_verify(const struct rsa_mpi_key *key, MPI m, MPI s)
 {
 	/* (1) Validate 0 <= s < n */
 	if (mpi_cmp_ui(s, 0) < 0 || mpi_cmp(s, key->n) >= 0)
@@ -71,7 +78,7 @@ static int _rsa_verify(const struct rsa_key *key, MPI m, MPI s)
 	return mpi_powm(m, s, key->e, key->n);
 }
 
-static inline struct rsa_key *rsa_get_key(struct crypto_akcipher *tfm)
+static inline struct rsa_mpi_key *rsa_get_key(struct crypto_akcipher *tfm)
 {
 	return akcipher_tfm_ctx(tfm);
 }
@@ -79,7 +86,7 @@ static inline struct rsa_key *rsa_get_key(struct crypto_akcipher *tfm)
 static int rsa_enc(struct akcipher_request *req)
 {
 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
-	const struct rsa_key *pkey = rsa_get_key(tfm);
+	const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
 	MPI m, c = mpi_alloc(0);
 	int ret = 0;
 	int sign;
@@ -118,7 +125,7 @@ err_free_c:
 static int rsa_dec(struct akcipher_request *req)
 {
 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
-	const struct rsa_key *pkey = rsa_get_key(tfm);
+	const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
 	MPI c, m = mpi_alloc(0);
 	int ret = 0;
 	int sign;
@@ -156,7 +163,7 @@ err_free_m:
 static int rsa_sign(struct akcipher_request *req)
 {
 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
-	const struct rsa_key *pkey = rsa_get_key(tfm);
+	const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
 	MPI m, s = mpi_alloc(0);
 	int ret = 0;
 	int sign;
@@ -195,7 +202,7 @@ err_free_s:
 static int rsa_verify(struct akcipher_request *req)
 {
 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
-	const struct rsa_key *pkey = rsa_get_key(tfm);
+	const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
 	MPI s, m = mpi_alloc(0);
 	int ret = 0;
 	int sign;
@@ -233,6 +240,16 @@ err_free_m:
 	return ret;
 }
 
+static void rsa_free_mpi_key(struct rsa_mpi_key *key)
+{
+	mpi_free(key->d);
+	mpi_free(key->e);
+	mpi_free(key->n);
+	key->d = NULL;
+	key->e = NULL;
+	key->n = NULL;
+}
+
 static int rsa_check_key_length(unsigned int len)
 {
 	switch (len) {
@@ -251,49 +268,87 @@ static int rsa_check_key_length(unsigned int len)
 static int rsa_set_pub_key(struct crypto_akcipher *tfm, const void *key,
 			   unsigned int keylen)
 {
-	struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
+	struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
+	struct rsa_key raw_key = {0};
 	int ret;
 
-	ret = rsa_parse_pub_key(pkey, key, keylen);
+	/* Free the old MPI key if any */
+	rsa_free_mpi_key(mpi_key);
+
+	ret = rsa_parse_pub_key(&raw_key, key, keylen);
 	if (ret)
 		return ret;
 
-	if (rsa_check_key_length(mpi_get_size(pkey->n) << 3)) {
-		rsa_free_key(pkey);
-		ret = -EINVAL;
+	mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
+	if (!mpi_key->e)
+		goto err;
+
+	mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
+	if (!mpi_key->n)
+		goto err;
+
+	if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
+		rsa_free_mpi_key(mpi_key);
+		return -EINVAL;
 	}
-	return ret;
+
+	return 0;
+
+err:
+	rsa_free_mpi_key(mpi_key);
+	return -ENOMEM;
 }
 
 static int rsa_set_priv_key(struct crypto_akcipher *tfm, const void *key,
 			    unsigned int keylen)
 {
-	struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
+	struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
+	struct rsa_key raw_key = {0};
 	int ret;
 
-	ret = rsa_parse_priv_key(pkey, key, keylen);
+	/* Free the old MPI key if any */
+	rsa_free_mpi_key(mpi_key);
+
+	ret = rsa_parse_priv_key(&raw_key, key, keylen);
 	if (ret)
 		return ret;
 
-	if (rsa_check_key_length(mpi_get_size(pkey->n) << 3)) {
-		rsa_free_key(pkey);
-		ret = -EINVAL;
+	mpi_key->d = mpi_read_raw_data(raw_key.d, raw_key.d_sz);
+	if (!mpi_key->d)
+		goto err;
+
+	mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
+	if (!mpi_key->e)
+		goto err;
+
+	mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
+	if (!mpi_key->n)
+		goto err;
+
+	if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
+		rsa_free_mpi_key(mpi_key);
+		return -EINVAL;
 	}
-	return ret;
+
+	return 0;
+
+err:
+	rsa_free_mpi_key(mpi_key);
+	return -ENOMEM;
 }
 
 static int rsa_max_size(struct crypto_akcipher *tfm)
 {
-	struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
+	struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);
 
 	return pkey->n ? mpi_get_size(pkey->n) : -EINVAL;
 }
 
 static void rsa_exit_tfm(struct crypto_akcipher *tfm)
 {
-	struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
+	struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);
 
-	rsa_free_key(pkey);
+	rsa_free_mpi_key(pkey);
 }
 
 static struct akcipher_alg rsa = {
@@ -310,7 +365,7 @@ static struct akcipher_alg rsa = {
 		.cra_driver_name = "rsa-generic",
 		.cra_priority = 100,
 		.cra_module = THIS_MODULE,
-		.cra_ctxsize = sizeof(struct rsa_key),
+		.cra_ctxsize = sizeof(struct rsa_mpi_key),
 	},
 };