KEYS: Provide missing asymmetric key subops for new key type ops [ver #2]

Provide the missing asymmetric key subops for new key type ops.  This
include query, encrypt, decrypt and create signature.  Verify signature
already exists.  Also provided are accessor functions for this:

	int query_asymmetric_key(const struct key *key,
				 struct kernel_pkey_query *info);

	int encrypt_blob(struct kernel_pkey_params *params,
			 const void *data, void *enc);
	int decrypt_blob(struct kernel_pkey_params *params,
			 const void *enc, void *data);
	int create_signature(struct kernel_pkey_params *params,
			     const void *data, void *enc);

The public_key_signature struct gains an encoding field to carry the
encoding for verify_signature().

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Marcel Holtmann <marcel@holtmann.org>
Reviewed-by: Marcel Holtmann <marcel@holtmann.org>
Reviewed-by: Denis Kenzior <denkenz@gmail.com>
Tested-by: Denis Kenzior <denkenz@gmail.com>
Signed-off-by: James Morris <james.morris@microsoft.com>

Documentation/crypto/asymmetric-keys.txt

@@ -183,6 +183,10 @@ and looks like the following:
 
 		void (*describe)(const struct key *key, struct seq_file *m);
 		void (*destroy)(void *payload);
+		int (*query)(const struct kernel_pkey_params *params,
+			     struct kernel_pkey_query *info);
+		int (*eds_op)(struct kernel_pkey_params *params,
+			      const void *in, void *out);
 		int (*verify_signature)(const struct key *key,
 					const struct public_key_signature *sig);
 	};
@@ -207,12 +211,22 @@ There are a number of operations defined by the subtype:
      asymmetric key will look after freeing the fingerprint and releasing the
      reference on the subtype module.
 
- (3) verify_signature().
+ (3) query().
 
-     Optional.  These are the entry points for the key usage operations.
-     Currently there is only the one defined.  If not set, the caller will be
-     given -ENOTSUPP.  The subtype may do anything it likes to implement an
-     operation, including offloading to hardware.
+     Mandatory.  This is a function for querying the capabilities of a key.
+
+ (4) eds_op().
+
+     Optional.  This is the entry point for the encryption, decryption and
+     signature creation operations (which are distinguished by the operation ID
+     in the parameter struct).  The subtype may do anything it likes to
+     implement an operation, including offloading to hardware.
+
+ (5) verify_signature().
+
+     Optional.  This is the entry point for signature verification.  The
+     subtype may do anything it likes to implement an operation, including
+     offloading to hardware.
 
 
 ==========================

crypto/asymmetric_keys/asymmetric_keys.h

@@ -16,3 +16,6 @@ extern struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id);
 extern int __asymmetric_key_hex_to_key_id(const char *id,
 					  struct asymmetric_key_id *match_id,
 					  size_t hexlen);
+
+extern int asymmetric_key_eds_op(struct kernel_pkey_params *params,
+				 const void *in, void *out);

crypto/asymmetric_keys/asymmetric_type.c

@@ -18,6 +18,7 @@
 #include <linux/slab.h>
 #include <linux/ctype.h>
 #include <keys/system_keyring.h>
+#include <keys/user-type.h>
 #include "asymmetric_keys.h"
 
 MODULE_LICENSE("GPL");
@@ -538,6 +539,45 @@ static struct key_restriction *asymmetric_lookup_restriction(
 	return ret;
 }
 
+int asymmetric_key_eds_op(struct kernel_pkey_params *params,
+			  const void *in, void *out)
+{
+	const struct asymmetric_key_subtype *subtype;
+	struct key *key = params->key;
+	int ret;
+
+	pr_devel("==>%s()\n", __func__);
+
+	if (key->type != &key_type_asymmetric)
+		return -EINVAL;
+	subtype = asymmetric_key_subtype(key);
+	if (!subtype ||
+	    !key->payload.data[0])
+		return -EINVAL;
+	if (!subtype->eds_op)
+		return -ENOTSUPP;
+
+	ret = subtype->eds_op(params, in, out);
+
+	pr_devel("<==%s() = %d\n", __func__, ret);
+	return ret;
+}
+
+static int asymmetric_key_verify_signature(struct kernel_pkey_params *params,
+					   const void *in, const void *in2)
+{
+	struct public_key_signature sig = {
+		.s_size		= params->in2_len,
+		.digest_size	= params->in_len,
+		.encoding	= params->encoding,
+		.hash_algo	= params->hash_algo,
+		.digest		= (void *)in,
+		.s		= (void *)in2,
+	};
+
+	return verify_signature(params->key, &sig);
+}
+
 struct key_type key_type_asymmetric = {
 	.name			= "asymmetric",
 	.preparse		= asymmetric_key_preparse,
@@ -548,6 +588,9 @@ struct key_type key_type_asymmetric = {
 	.destroy		= asymmetric_key_destroy,
 	.describe		= asymmetric_key_describe,
 	.lookup_restriction	= asymmetric_lookup_restriction,
+	.asym_query		= query_asymmetric_key,
+	.asym_eds_op		= asymmetric_key_eds_op,
+	.asym_verify_signature	= asymmetric_key_verify_signature,
 };
 EXPORT_SYMBOL_GPL(key_type_asymmetric);
 

crypto/asymmetric_keys/signature.c

@@ -16,7 +16,9 @@
 #include <linux/export.h>
 #include <linux/err.h>
 #include <linux/slab.h>
+#include <linux/keyctl.h>
 #include <crypto/public_key.h>
+#include <keys/user-type.h>
 #include "asymmetric_keys.h"
 
 /*
@@ -36,6 +38,99 @@ void public_key_signature_free(struct public_key_signature *sig)
 }
 EXPORT_SYMBOL_GPL(public_key_signature_free);
 
+/**
+ * query_asymmetric_key - Get information about an aymmetric key.
+ * @params: Various parameters.
+ * @info: Where to put the information.
+ */
+int query_asymmetric_key(const struct kernel_pkey_params *params,
+			 struct kernel_pkey_query *info)
+{
+	const struct asymmetric_key_subtype *subtype;
+	struct key *key = params->key;
+	int ret;
+
+	pr_devel("==>%s()\n", __func__);
+
+	if (key->type != &key_type_asymmetric)
+		return -EINVAL;
+	subtype = asymmetric_key_subtype(key);
+	if (!subtype ||
+	    !key->payload.data[0])
+		return -EINVAL;
+	if (!subtype->query)
+		return -ENOTSUPP;
+
+	ret = subtype->query(params, info);
+
+	pr_devel("<==%s() = %d\n", __func__, ret);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(query_asymmetric_key);
+
+/**
+ * encrypt_blob - Encrypt data using an asymmetric key
+ * @params: Various parameters
+ * @data: Data blob to be encrypted, length params->data_len
+ * @enc: Encrypted data buffer, length params->enc_len
+ *
+ * Encrypt the specified data blob using the private key specified by
+ * params->key.  The encrypted data is wrapped in an encoding if
+ * params->encoding is specified (eg. "pkcs1").
+ *
+ * Returns the length of the data placed in the encrypted data buffer or an
+ * error.
+ */
+int encrypt_blob(struct kernel_pkey_params *params,
+		 const void *data, void *enc)
+{
+	params->op = kernel_pkey_encrypt;
+	return asymmetric_key_eds_op(params, data, enc);
+}
+EXPORT_SYMBOL_GPL(encrypt_blob);
+
+/**
+ * decrypt_blob - Decrypt data using an asymmetric key
+ * @params: Various parameters
+ * @enc: Encrypted data to be decrypted, length params->enc_len
+ * @data: Decrypted data buffer, length params->data_len
+ *
+ * Decrypt the specified data blob using the private key specified by
+ * params->key.  The decrypted data is wrapped in an encoding if
+ * params->encoding is specified (eg. "pkcs1").
+ *
+ * Returns the length of the data placed in the decrypted data buffer or an
+ * error.
+ */
+int decrypt_blob(struct kernel_pkey_params *params,
+		 const void *enc, void *data)
+{
+	params->op = kernel_pkey_decrypt;
+	return asymmetric_key_eds_op(params, enc, data);
+}
+EXPORT_SYMBOL_GPL(decrypt_blob);
+
+/**
+ * create_signature - Sign some data using an asymmetric key
+ * @params: Various parameters
+ * @data: Data blob to be signed, length params->data_len
+ * @enc: Signature buffer, length params->enc_len
+ *
+ * Sign the specified data blob using the private key specified by params->key.
+ * The signature is wrapped in an encoding if params->encoding is specified
+ * (eg. "pkcs1").  If the encoding needs to know the digest type, this can be
+ * passed through params->hash_algo (eg. "sha1").
+ *
+ * Returns the length of the data placed in the signature buffer or an error.
+ */
+int create_signature(struct kernel_pkey_params *params,
+		     const void *data, void *enc)
+{
+	params->op = kernel_pkey_sign;
+	return asymmetric_key_eds_op(params, data, enc);
+}
+EXPORT_SYMBOL_GPL(create_signature);
+
 /**
  * verify_signature - Initiate the use of an asymmetric key to verify a signature
  * @key: The asymmetric key to verify against

include/crypto/public_key.h

@@ -14,6 +14,8 @@
 #ifndef _LINUX_PUBLIC_KEY_H
 #define _LINUX_PUBLIC_KEY_H
 
+#include <linux/keyctl.h>
+
 /*
  * Cryptographic data for the public-key subtype of the asymmetric key type.
  *
@@ -40,6 +42,7 @@ struct public_key_signature {
 	u8 digest_size;		/* Number of bytes in digest */
 	const char *pkey_algo;
 	const char *hash_algo;
+	const char *encoding;
 };
 
 extern void public_key_signature_free(struct public_key_signature *sig);
@@ -65,8 +68,14 @@ extern int restrict_link_by_key_or_keyring_chain(struct key *trust_keyring,
 						 const union key_payload *payload,
 						 struct key *trusted);
 
-extern int verify_signature(const struct key *key,
-			    const struct public_key_signature *sig);
+extern int query_asymmetric_key(const struct kernel_pkey_params *,
+				struct kernel_pkey_query *);
+
+extern int encrypt_blob(struct kernel_pkey_params *, const void *, void *);
+extern int decrypt_blob(struct kernel_pkey_params *, const void *, void *);
+extern int create_signature(struct kernel_pkey_params *, const void *, void *);
+extern int verify_signature(const struct key *,
+			    const struct public_key_signature *);
 
 int public_key_verify_signature(const struct public_key *pkey,
 				const struct public_key_signature *sig);

include/keys/asymmetric-subtype.h

@@ -17,6 +17,8 @@
 #include <linux/seq_file.h>
 #include <keys/asymmetric-type.h>
 
+struct kernel_pkey_query;
+struct kernel_pkey_params;
 struct public_key_signature;
 
 /*
@@ -34,6 +36,13 @@ struct asymmetric_key_subtype {
 	/* Destroy a key of this subtype */
 	void (*destroy)(void *payload_crypto, void *payload_auth);
 
+	int (*query)(const struct kernel_pkey_params *params,
+		     struct kernel_pkey_query *info);
+
+	/* Encrypt/decrypt/sign data */
+	int (*eds_op)(struct kernel_pkey_params *params,
+		      const void *in, void *out);
+
 	/* Verify the signature on a key of this subtype (optional) */
 	int (*verify_signature)(const struct key *key,
 				const struct public_key_signature *sig);