/* SPDX-License-Identifier: GPL-2.0-or-later */
/* Asymmetric public-key algorithm definitions
 *
 * See Documentation/crypto/asymmetric-keys.rst
 *
 * 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

#include <linux/errno.h>
#include <linux/keyctl.h>
#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;
        unsigned long key_eflags;       /* key extension flags */
#define KEY_EFLAG_CA            0       /* set if the CA basic constraints is set */
#define KEY_EFLAG_DIGITALSIG    1       /* set if the digitalSignature usage is set */
#define KEY_EFLAG_KEYCERTSIGN   2       /* set if the keyCertSign usage is set */
};

extern void public_key_free(struct public_key *key);

/*
 * Public key cryptography signature data
 */
struct public_key_signature {
        struct asymmetric_key_id *auth_ids[3];
        u8 *s;                  /* Signature */
        u8 *m;                  /* Message data to pass to verifier */
        u32 s_size;             /* Number of bytes in signature */
        u32 m_size;             /* Number of bytes in ->m */
        bool m_free;            /* T if ->m needs freeing */
        bool algo_takes_data;   /* T if public key algo operates on data, not a hash */
        const char *pkey_algo;
        const char *hash_algo;
        const char *encoding;
};

extern void public_key_signature_free(struct public_key_signature *sig);

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);

#if IS_REACHABLE(CONFIG_ASYMMETRIC_KEY_TYPE)
extern int restrict_link_by_ca(struct key *dest_keyring,
                               const struct key_type *type,
                               const union key_payload *payload,
                               struct key *trust_keyring);
int restrict_link_by_digsig(struct key *dest_keyring,
                            const struct key_type *type,
                            const union key_payload *payload,
                            struct key *trust_keyring);
#else
static inline int restrict_link_by_ca(struct key *dest_keyring,
                                      const struct key_type *type,
                                      const union key_payload *payload,
                                      struct key *trust_keyring)
{
        return 0;
}

static inline int restrict_link_by_digsig(struct key *dest_keyring,
                                          const struct key_type *type,
                                          const union key_payload *payload,
                                          struct key *trust_keyring)
{
        return 0;
}
#endif

extern int query_asymmetric_key(const struct kernel_pkey_params *,
                                struct kernel_pkey_query *);

extern int verify_signature(const struct key *,
                            const struct public_key_signature *);

#if IS_REACHABLE(CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE)
int public_key_verify_signature(const struct public_key *pkey,
                                const struct public_key_signature *sig);
#else
static inline
int public_key_verify_signature(const struct public_key *pkey,
                                const struct public_key_signature *sig)
{
        return -EINVAL;
}
#endif

#endif /* _LINUX_PUBLIC_KEY_H */