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sshkey.h revision 1.25
      1 /*	$NetBSD: sshkey.h,v 1.25 2025/12/28 09:54:07 nia Exp $	*/
      2 /* $OpenBSD: sshkey.h,v 1.70 2025/08/29 03:50:38 djm Exp $ */
      3 
      4 /*
      5  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 #ifndef SSHKEY_H
     28 #define SSHKEY_H
     29 
     30 #include "includes.h"
     31 #include <sys/types.h>
     32 
     33 #ifdef WITH_OPENSSL
     34 #include <openssl/rsa.h>
     35 #include <openssl/ec.h>
     36 #include <openssl/ecdsa.h>
     37 #include <openssl/evp.h>
     38 #define SSH_OPENSSL_VERSION OpenSSL_version(OPENSSL_VERSION)
     39 #else /* OPENSSL */
     40 #define BIGNUM		void
     41 #define RSA		void
     42 #define EC_KEY		void
     43 #define EC_GROUP	void
     44 #define EC_POINT	void
     45 #define EVP_PKEY	void
     46 #define SSH_OPENSSL_VERSION "without OpenSSL"
     47 #endif /* WITH_OPENSSL */
     48 
     49 #define SSH_RSA_MINIMUM_MODULUS_SIZE	1024
     50 #define SSH_KEY_MAX_SIGN_DATA_SIZE	(1 << 20)
     51 
     52 struct sshbuf;
     53 
     54 /* Key types */
     55 enum sshkey_types {
     56 	KEY_RSA,
     57 	KEY_ECDSA,
     58 	KEY_ED25519,
     59 	KEY_RSA_CERT,
     60 	KEY_ECDSA_CERT,
     61 	KEY_ED25519_CERT,
     62 	KEY_ECDSA_SK,
     63 	KEY_ECDSA_SK_CERT,
     64 	KEY_ED25519_SK,
     65 	KEY_ED25519_SK_CERT,
     66 	KEY_UNSPEC
     67 };
     68 
     69 /* Default fingerprint hash */
     70 #define SSH_FP_HASH_DEFAULT	SSH_DIGEST_SHA256
     71 
     72 /* Fingerprint representation formats */
     73 enum sshkey_fp_rep {
     74 	SSH_FP_DEFAULT = 0,
     75 	SSH_FP_HEX,
     76 	SSH_FP_BASE64,
     77 	SSH_FP_BUBBLEBABBLE,
     78 	SSH_FP_RANDOMART
     79 };
     80 
     81 /* Private key serialisation formats, used on the wire */
     82 enum sshkey_serialize_rep {
     83 	SSHKEY_SERIALIZE_DEFAULT = 0,
     84 };
     85 
     86 /* Private key disk formats */
     87 enum sshkey_private_format {
     88 	SSHKEY_PRIVATE_OPENSSH = 0,
     89 	SSHKEY_PRIVATE_PEM = 1,
     90 	SSHKEY_PRIVATE_PKCS8 = 2,
     91 };
     92 
     93 /* key is stored in external hardware */
     94 #define SSHKEY_FLAG_EXT		0x0001
     95 
     96 #define SSHKEY_CERT_MAX_PRINCIPALS	256
     97 /* XXX opaquify? */
     98 struct sshkey_cert {
     99 	struct sshbuf	*certblob; /* Kept around for use on wire */
    100 	u_int		 type; /* SSH2_CERT_TYPE_USER or SSH2_CERT_TYPE_HOST */
    101 	u_int64_t	 serial;
    102 	char		*key_id;
    103 	u_int		 nprincipals;
    104 	char		**principals;
    105 	u_int64_t	 valid_after, valid_before;
    106 	struct sshbuf	*critical;
    107 	struct sshbuf	*extensions;
    108 	struct sshkey	*signature_key;
    109 	char		*signature_type;
    110 };
    111 
    112 /* XXX opaquify? */
    113 struct sshkey {
    114 	int	 type;
    115 	int	 flags;
    116 	/* KEY_ECDSA and KEY_ECDSA_SK */
    117 	int	 ecdsa_nid;	/* NID of curve */
    118 	/* libcrypto-backed keys */
    119 	EVP_PKEY *pkey;
    120 	/* KEY_ED25519 and KEY_ED25519_SK */
    121 	u_char	*ed25519_sk;
    122 	u_char	*ed25519_pk;
    123 	/* KEY_ECDSA_SK and KEY_ED25519_SK */
    124 	char	*sk_application;
    125 	uint8_t	sk_flags;
    126 	struct sshbuf *sk_key_handle;
    127 	struct sshbuf *sk_reserved;
    128 	/* Certificates */
    129 	struct sshkey_cert *cert;
    130 	/* Private key shielding */
    131 	u_char	*shielded_private;
    132 	size_t	shielded_len;
    133 	u_char	*shield_prekey;
    134 	size_t	shield_prekey_len;
    135 };
    136 
    137 #define	ED25519_SK_SZ	crypto_sign_ed25519_SECRETKEYBYTES
    138 #define	ED25519_PK_SZ	crypto_sign_ed25519_PUBLICKEYBYTES
    139 
    140 /* Additional fields contained in signature */
    141 struct sshkey_sig_details {
    142 	uint32_t sk_counter;	/* U2F signature counter */
    143 	uint8_t sk_flags;	/* U2F signature flags; see ssh-sk.h */
    144 };
    145 
    146 struct sshkey_impl_funcs {
    147 	u_int (*size)(const struct sshkey *);	/* optional */
    148 	int (*alloc)(struct sshkey *);		/* optional */
    149 	void (*cleanup)(struct sshkey *);	/* optional */
    150 	int (*equal)(const struct sshkey *, const struct sshkey *);
    151 	int (*serialize_public)(const struct sshkey *, struct sshbuf *,
    152 	    enum sshkey_serialize_rep);
    153 	int (*deserialize_public)(const char *, struct sshbuf *,
    154 	    struct sshkey *);
    155 	int (*serialize_private)(const struct sshkey *, struct sshbuf *,
    156 	    enum sshkey_serialize_rep);
    157 	int (*deserialize_private)(const char *, struct sshbuf *,
    158 	    struct sshkey *);
    159 	int (*generate)(struct sshkey *, int);	/* optional */
    160 	int (*copy_public)(const struct sshkey *, struct sshkey *);
    161 	int (*sign)(struct sshkey *, u_char **, size_t *,
    162 	    const u_char *, size_t, const char *,
    163 	    const char *, const char *, u_int); /* optional */
    164 	int (*verify)(const struct sshkey *, const u_char *, size_t,
    165 	    const u_char *, size_t, const char *, u_int,
    166 	    struct sshkey_sig_details **);
    167 };
    168 
    169 struct sshkey_impl {
    170 	const char *name;
    171 	const char *shortname;
    172 	const char *sigalg;
    173 	int type;
    174 	int nid;
    175 	int cert;
    176 	int sigonly;
    177 	int keybits;
    178 	const struct sshkey_impl_funcs *funcs;
    179 };
    180 
    181 struct sshkey	*sshkey_new(int);
    182 void		 sshkey_free(struct sshkey *);
    183 int		 sshkey_equal_public(const struct sshkey *,
    184     const struct sshkey *);
    185 int		 sshkey_equal(const struct sshkey *, const struct sshkey *);
    186 char		*sshkey_fingerprint(const struct sshkey *,
    187     int, enum sshkey_fp_rep);
    188 int		 sshkey_fingerprint_raw(const struct sshkey *k,
    189     int, u_char **retp, size_t *lenp);
    190 const char	*sshkey_type(const struct sshkey *);
    191 const char	*sshkey_cert_type(const struct sshkey *);
    192 int		 sshkey_format_text(const struct sshkey *, struct sshbuf *);
    193 int		 sshkey_write(const struct sshkey *, FILE *);
    194 int		 sshkey_read(struct sshkey *, char **);
    195 u_int		 sshkey_size(const struct sshkey *);
    196 
    197 int		 sshkey_generate(int type, u_int bits, struct sshkey **keyp);
    198 int		 sshkey_from_private(const struct sshkey *, struct sshkey **);
    199 
    200 int		 sshkey_is_shielded(struct sshkey *);
    201 int		 sshkey_shield_private(struct sshkey *);
    202 int		 sshkey_unshield_private(struct sshkey *);
    203 
    204 int	 sshkey_type_from_name(const char *);
    205 int	 sshkey_type_from_shortname(const char *);
    206 int	 sshkey_is_cert(const struct sshkey *);
    207 int	 sshkey_is_sk(const struct sshkey *);
    208 int	 sshkey_type_is_cert(int);
    209 int	 sshkey_type_plain(int);
    210 
    211 /* Returns non-zero if key name match sigalgs pattern list. (handles RSA) */
    212 int	 sshkey_match_keyname_to_sigalgs(const char *, const char *);
    213 
    214 int	 sshkey_to_certified(struct sshkey *);
    215 int	 sshkey_drop_cert(struct sshkey *);
    216 int	 sshkey_cert_copy(const struct sshkey *, struct sshkey *);
    217 int	 sshkey_cert_check_authority(const struct sshkey *, int, int, int,
    218     uint64_t, const char *, const char **);
    219 int	 sshkey_cert_check_authority_now(const struct sshkey *, int, int, int,
    220     const char *, const char **);
    221 int	 sshkey_cert_check_host(const struct sshkey *, const char *,
    222     int , const char *, const char **);
    223 size_t	 sshkey_format_cert_validity(const struct sshkey_cert *,
    224     char *, size_t) __attribute__((__bounded__(__string__, 2, 3)));
    225 int	 sshkey_check_cert_sigtype(const struct sshkey *, const char *);
    226 
    227 int	 sshkey_certify(struct sshkey *, struct sshkey *,
    228     const char *, const char *, const char *);
    229 /* Variant allowing use of a custom signature function (e.g. for ssh-agent) */
    230 typedef int sshkey_certify_signer(struct sshkey *, u_char **, size_t *,
    231     const u_char *, size_t, const char *, const char *, const char *,
    232     u_int, void *);
    233 int	 sshkey_certify_custom(struct sshkey *, struct sshkey *, const char *,
    234     const char *, const char *, sshkey_certify_signer *, void *);
    235 
    236 int		 sshkey_ecdsa_nid_from_name(const char *);
    237 int		 sshkey_curve_name_to_nid(const char *);
    238 const char *	 sshkey_curve_nid_to_name(int);
    239 u_int		 sshkey_curve_nid_to_bits(int);
    240 int		 sshkey_ecdsa_bits_to_nid(int);
    241 int		 sshkey_ecdsa_key_to_nid(const EC_KEY *);
    242 int		 sshkey_ecdsa_pkey_to_nid(EVP_PKEY *);
    243 int		 sshkey_ec_nid_to_hash_alg(int nid);
    244 int		 sshkey_ec_validate_public(const EC_GROUP *, const EC_POINT *);
    245 int		 sshkey_ec_validate_private(const EC_KEY *);
    246 const char	*sshkey_ssh_name(const struct sshkey *);
    247 const char	*sshkey_ssh_name_plain(const struct sshkey *);
    248 int		 sshkey_names_valid2(const char *, int, int);
    249 char		*sshkey_alg_list(int, int, int, char);
    250 
    251 int	 sshkey_from_blob(const u_char *, size_t, struct sshkey **);
    252 int	 sshkey_fromb(struct sshbuf *, struct sshkey **);
    253 int	 sshkey_froms(struct sshbuf *, struct sshkey **);
    254 int	 sshkey_to_blob(const struct sshkey *, u_char **, size_t *);
    255 int	 sshkey_to_base64(const struct sshkey *, char **);
    256 int	 sshkey_putb(const struct sshkey *, struct sshbuf *);
    257 int	 sshkey_puts(const struct sshkey *, struct sshbuf *);
    258 int	 sshkey_plain_to_blob(const struct sshkey *, u_char **, size_t *);
    259 int	 sshkey_putb_plain(const struct sshkey *, struct sshbuf *);
    260 int	 sshkey_puts_plain(const struct sshkey *, struct sshbuf *);
    261 
    262 int	 sshkey_sign(struct sshkey *, u_char **, size_t *,
    263     const u_char *, size_t, const char *, const char *, const char *, u_int);
    264 int	 sshkey_verify(const struct sshkey *, const u_char *, size_t,
    265     const u_char *, size_t, const char *, u_int, struct sshkey_sig_details **);
    266 int	 sshkey_check_sigtype(const u_char *, size_t, const char *);
    267 const char *sshkey_sigalg_by_name(const char *);
    268 int	 sshkey_get_sigtype(const u_char *, size_t, char **);
    269 
    270 /* Signing and verification backend for libcrypto-backed keys */
    271 int	sshkey_pkey_digest_sign(EVP_PKEY*, int, u_char **,
    272     size_t *, const u_char *, size_t);
    273 int	sshkey_pkey_digest_verify(EVP_PKEY *, int, const u_char *,
    274     size_t, u_char *, size_t);
    275 
    276 /* for debug */
    277 void	sshkey_dump_ec_point(const EC_GROUP *, const EC_POINT *);
    278 void	sshkey_dump_ec_key(const EC_KEY *);
    279 
    280 /* private key parsing and serialisation */
    281 int	sshkey_private_serialize(struct sshkey *key, struct sshbuf *buf);
    282 int	sshkey_private_deserialize(struct sshbuf *buf,  struct sshkey **keyp);
    283 
    284 /* private key file format parsing and serialisation */
    285 int	sshkey_private_to_fileblob(struct sshkey *key, struct sshbuf *blob,
    286     const char *passphrase, const char *comment,
    287     int format, const char *openssh_format_cipher, int openssh_format_rounds);
    288 int	sshkey_parse_private_fileblob(struct sshbuf *buffer,
    289     const char *passphrase, struct sshkey **keyp, char **commentp);
    290 int	sshkey_parse_private_fileblob_type(struct sshbuf *blob, int type,
    291     const char *passphrase, struct sshkey **keyp, char **commentp);
    292 int	sshkey_parse_pubkey_from_private_fileblob_type(struct sshbuf *blob,
    293     int type, struct sshkey **pubkeyp);
    294 
    295 int sshkey_check_rsa_length(const struct sshkey *, int);
    296 /* XXX should be internal, but used by ssh-keygen */
    297 int ssh_rsa_complete_crt_parameters(const BIGNUM *, const BIGNUM *,
    298     const BIGNUM *, const BIGNUM *, BIGNUM **, BIGNUM **);
    299 
    300 void	 sshkey_sig_details_free(struct sshkey_sig_details *);
    301 
    302 #ifdef WITH_OPENSSL
    303 int	sshkey_ecdsa_fixup_group(EVP_PKEY *k); /* ssh-ecdsa.c */
    304 #endif
    305 
    306 #ifdef SSHKEY_INTERNAL
    307 int	sshkey_sk_fields_equal(const struct sshkey *a, const struct sshkey *b);
    308 void	sshkey_sk_cleanup(struct sshkey *k);
    309 int	sshkey_serialize_sk(const struct sshkey *key, struct sshbuf *b);
    310 int	sshkey_copy_public_sk(const struct sshkey *from, struct sshkey *to);
    311 int	sshkey_deserialize_sk(struct sshbuf *b, struct sshkey *key);
    312 int	sshkey_serialize_private_sk(const struct sshkey *key,
    313     struct sshbuf *buf);
    314 int	sshkey_private_deserialize_sk(struct sshbuf *buf, struct sshkey *k);
    315 #ifdef WITH_OPENSSL
    316 int	check_rsa_length(const RSA *rsa); /* XXX remove */
    317 int	ssh_rsa_hash_id_from_keyname(const char *);
    318 const char *ssh_rsa_hash_alg_ident(int);
    319 int	ssh_rsa_encode_store_sig(int, const u_char *, size_t,
    320 	    u_char **, size_t *);
    321 int	ssh_ecdsa_encode_store_sig(const struct sshkey *,
    322 	    const BIGNUM *, const BIGNUM *, u_char **, size_t *);
    323 #endif
    324 int	ssh_ed25519_encode_store_sig(const u_char *, size_t,
    325 	    u_char **, size_t *);
    326 #endif
    327 
    328 #ifndef WITH_OPENSSL
    329 #undef RSA
    330 #undef EC_KEY
    331 #undef EC_GROUP
    332 #undef EC_POINT
    333 #undef EVP_PKEY
    334 #endif /* WITH_OPENSSL */
    335 
    336 #endif /* SSHKEY_H */
    337