lib: crypto: add public key utility

Imported from linux kernel v5.3:
 asymmetric-type.h with changes marked as __UBOOT__
 asymmetric_type.c with changes marked as __UBOOT__
 public_key.h with changes marked as __UBOOT__
 public_key.c with changes marked as __UBOOT__

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

2 files changed, 178 insertions, 0 deletions

diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h
new file mode 100644
index 0000000..436a1ee
--- /dev/null
+++ b/include/crypto/public_key.h
@@ -0,0 +1,90 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Asymmetric public-key algorithm definitions
+ *
+ * See Documentation/crypto/asymmetric-keys.txt
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#ifndef _LINUX_PUBLIC_KEY_H
+#define _LINUX_PUBLIC_KEY_H
+
+#ifdef __UBOOT__
+#include <linux/types.h>
+#else
+#include <linux/keyctl.h>
+#endif
+#include <linux/oid_registry.h>
+
+/*
+ * Cryptographic data for the public-key subtype of the asymmetric key type.
+ *
+ * Note that this may include private part of the key as well as the public
+ * part.
+ */
+struct public_key {
+	void *key;
+	u32 keylen;
+	enum OID algo;
+	void *params;
+	u32 paramlen;
+	bool key_is_private;
+	const char *id_type;
+	const char *pkey_algo;
+};
+
+extern void public_key_free(struct public_key *key);
+
+/*
+ * Public key cryptography signature data
+ */
+struct public_key_signature {
+	struct asymmetric_key_id *auth_ids[2];
+	u8 *s;			/* Signature */
+	u32 s_size;		/* Number of bytes in signature */
+	u8 *digest;
+	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);
+
+#ifndef __UBOOT__
+extern struct asymmetric_key_subtype public_key_subtype;
+
+struct key;
+struct key_type;
+union key_payload;
+
+extern int restrict_link_by_signature(struct key *dest_keyring,
+				      const struct key_type *type,
+				      const union key_payload *payload,
+				      struct key *trust_keyring);
+
+extern int restrict_link_by_key_or_keyring(struct key *dest_keyring,
+					   const struct key_type *type,
+					   const union key_payload *payload,
+					   struct key *trusted);
+
+extern int restrict_link_by_key_or_keyring_chain(struct key *trust_keyring,
+						 const struct key_type *type,
+						 const union key_payload *payload,
+						 struct key *trusted);
+
+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);
+#endif /* !__UBOOT__ */
+
+#endif /* _LINUX_PUBLIC_KEY_H */
diff --git a/include/keys/asymmetric-type.h b/include/keys/asymmetric-type.h
new file mode 100644
index 0000000..47d8391
--- /dev/null
+++ b/include/keys/asymmetric-type.h
@@ -0,0 +1,88 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Asymmetric Public-key cryptography key type interface
+ *
+ * See Documentation/crypto/asymmetric-keys.txt
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#ifndef _KEYS_ASYMMETRIC_TYPE_H
+#define _KEYS_ASYMMETRIC_TYPE_H
+
+#ifndef __UBOOT__
+#include <linux/key-type.h>
+#include <linux/verification.h>
+
+extern struct key_type key_type_asymmetric;
+
+/*
+ * The key payload is four words.  The asymmetric-type key uses them as
+ * follows:
+ */
+enum asymmetric_payload_bits {
+	asym_crypto,		/* The data representing the key */
+	asym_subtype,		/* Pointer to an asymmetric_key_subtype struct */
+	asym_key_ids,		/* Pointer to an asymmetric_key_ids struct */
+	asym_auth		/* The key's authorisation (signature, parent key ID) */
+};
+#endif /* !__UBOOT__ */
+
+/*
+ * Identifiers for an asymmetric key ID.  We have three ways of looking up a
+ * key derived from an X.509 certificate:
+ *
+ * (1) Serial Number & Issuer.  Non-optional.  This is the only valid way to
+ *     map a PKCS#7 signature to an X.509 certificate.
+ *
+ * (2) Issuer & Subject Unique IDs.  Optional.  These were the original way to
+ *     match X.509 certificates, but have fallen into disuse in favour of (3).
+ *
+ * (3) Auth & Subject Key Identifiers.  Optional.  SKIDs are only provided on
+ *     CA keys that are intended to sign other keys, so don't appear in end
+ *     user certificates unless forced.
+ *
+ * We could also support an PGP key identifier, which is just a SHA1 sum of the
+ * public key and certain parameters, but since we don't support PGP keys at
+ * the moment, we shall ignore those.
+ *
+ * What we actually do is provide a place where binary identifiers can be
+ * stashed and then compare against them when checking for an id match.
+ */
+struct asymmetric_key_id {
+	unsigned short	len;
+	unsigned char	data[];
+};
+
+struct asymmetric_key_ids {
+	void		*id[2];
+};
+
+extern bool asymmetric_key_id_same(const struct asymmetric_key_id *kid1,
+				   const struct asymmetric_key_id *kid2);
+
+extern bool asymmetric_key_id_partial(const struct asymmetric_key_id *kid1,
+				      const struct asymmetric_key_id *kid2);
+
+extern struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
+							    size_t len_1,
+							    const void *val_2,
+							    size_t len_2);
+#ifndef __UBOOT__
+static inline
+const struct asymmetric_key_ids *asymmetric_key_ids(const struct key *key)
+{
+	return key->payload.data[asym_key_ids];
+}
+
+extern struct key *find_asymmetric_key(struct key *keyring,
+				       const struct asymmetric_key_id *id_0,
+				       const struct asymmetric_key_id *id_1,
+				       bool partial);
+#endif
+
+/*
+ * The payload is at the discretion of the subtype.
+ */
+
+#endif /* _KEYS_ASYMMETRIC_TYPE_H */