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sshkey.h revision 1.1.1.22
      1 /* $OpenBSD: sshkey.h,v 1.62 2023/06/21 05:10:26 djm Exp $ */
      2 
      3 /*
      4  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     25  */
     26 #ifndef SSHKEY_H
     27 #define SSHKEY_H
     28 
     29 #include <sys/types.h>
     30 
     31 #ifdef WITH_OPENSSL
     32 #include <openssl/rsa.h>
     33 #include <openssl/dsa.h>
     34 #include <openssl/ec.h>
     35 #include <openssl/ecdsa.h>
     36 #define SSH_OPENSSL_VERSION OpenSSL_version(OPENSSL_VERSION)
     37 #else /* OPENSSL */
     38 #define BIGNUM		void
     39 #define RSA		void
     40 #define DSA		void
     41 #define EC_KEY		void
     42 #define EC_GROUP	void
     43 #define EC_POINT	void
     44 #define SSH_OPENSSL_VERSION "without OpenSSL"
     45 #endif /* WITH_OPENSSL */
     46 
     47 #define SSH_RSA_MINIMUM_MODULUS_SIZE	1024
     48 #define SSH_KEY_MAX_SIGN_DATA_SIZE	(1 << 20)
     49 
     50 struct sshbuf;
     51 
     52 /* Key types */
     53 enum sshkey_types {
     54 	KEY_RSA,
     55 	KEY_DSA,
     56 	KEY_ECDSA,
     57 	KEY_ED25519,
     58 	KEY_RSA_CERT,
     59 	KEY_DSA_CERT,
     60 	KEY_ECDSA_CERT,
     61 	KEY_ED25519_CERT,
     62 	KEY_XMSS,
     63 	KEY_XMSS_CERT,
     64 	KEY_ECDSA_SK,
     65 	KEY_ECDSA_SK_CERT,
     66 	KEY_ED25519_SK,
     67 	KEY_ED25519_SK_CERT,
     68 	KEY_UNSPEC
     69 };
     70 
     71 /* Default fingerprint hash */
     72 #define SSH_FP_HASH_DEFAULT	SSH_DIGEST_SHA256
     73 
     74 /* Fingerprint representation formats */
     75 enum sshkey_fp_rep {
     76 	SSH_FP_DEFAULT = 0,
     77 	SSH_FP_HEX,
     78 	SSH_FP_BASE64,
     79 	SSH_FP_BUBBLEBABBLE,
     80 	SSH_FP_RANDOMART
     81 };
     82 
     83 /* Private key serialisation formats, used on the wire */
     84 enum sshkey_serialize_rep {
     85 	SSHKEY_SERIALIZE_DEFAULT = 0,
     86 	SSHKEY_SERIALIZE_STATE = 1,	/* only state is serialized */
     87 	SSHKEY_SERIALIZE_FULL = 2,	/* include keys for saving to disk */
     88 	SSHKEY_SERIALIZE_SHIELD = 3,	/* everything, for encrypting in ram */
     89 	SSHKEY_SERIALIZE_INFO = 254,	/* minimal information */
     90 };
     91 
     92 /* Private key disk formats */
     93 enum sshkey_private_format {
     94 	SSHKEY_PRIVATE_OPENSSH = 0,
     95 	SSHKEY_PRIVATE_PEM = 1,
     96 	SSHKEY_PRIVATE_PKCS8 = 2,
     97 };
     98 
     99 /* key is stored in external hardware */
    100 #define SSHKEY_FLAG_EXT		0x0001
    101 
    102 #define SSHKEY_CERT_MAX_PRINCIPALS	256
    103 /* XXX opaquify? */
    104 struct sshkey_cert {
    105 	struct sshbuf	*certblob; /* Kept around for use on wire */
    106 	u_int		 type; /* SSH2_CERT_TYPE_USER or SSH2_CERT_TYPE_HOST */
    107 	u_int64_t	 serial;
    108 	char		*key_id;
    109 	u_int		 nprincipals;
    110 	char		**principals;
    111 	u_int64_t	 valid_after, valid_before;
    112 	struct sshbuf	*critical;
    113 	struct sshbuf	*extensions;
    114 	struct sshkey	*signature_key;
    115 	char		*signature_type;
    116 };
    117 
    118 /* XXX opaquify? */
    119 struct sshkey {
    120 	int	 type;
    121 	int	 flags;
    122 	/* KEY_RSA */
    123 	RSA	*rsa;
    124 	/* KEY_DSA */
    125 	DSA	*dsa;
    126 	/* KEY_ECDSA and KEY_ECDSA_SK */
    127 	int	 ecdsa_nid;	/* NID of curve */
    128 	EC_KEY	*ecdsa;
    129 	/* KEY_ED25519 and KEY_ED25519_SK */
    130 	u_char	*ed25519_sk;
    131 	u_char	*ed25519_pk;
    132 	/* KEY_XMSS */
    133 	char	*xmss_name;
    134 	char	*xmss_filename;	/* for state file updates */
    135 	void	*xmss_state;	/* depends on xmss_name, opaque */
    136 	u_char	*xmss_sk;
    137 	u_char	*xmss_pk;
    138 	/* KEY_ECDSA_SK and KEY_ED25519_SK */
    139 	char	*sk_application;
    140 	uint8_t	sk_flags;
    141 	struct sshbuf *sk_key_handle;
    142 	struct sshbuf *sk_reserved;
    143 	/* Certificates */
    144 	struct sshkey_cert *cert;
    145 	/* Private key shielding */
    146 	u_char	*shielded_private;
    147 	size_t	shielded_len;
    148 	u_char	*shield_prekey;
    149 	size_t	shield_prekey_len;
    150 };
    151 
    152 #define	ED25519_SK_SZ	crypto_sign_ed25519_SECRETKEYBYTES
    153 #define	ED25519_PK_SZ	crypto_sign_ed25519_PUBLICKEYBYTES
    154 
    155 /* Additional fields contained in signature */
    156 struct sshkey_sig_details {
    157 	uint32_t sk_counter;	/* U2F signature counter */
    158 	uint8_t sk_flags;	/* U2F signature flags; see ssh-sk.h */
    159 };
    160 
    161 struct sshkey_impl_funcs {
    162 	u_int (*size)(const struct sshkey *);	/* optional */
    163 	int (*alloc)(struct sshkey *);		/* optional */
    164 	void (*cleanup)(struct sshkey *);	/* optional */
    165 	int (*equal)(const struct sshkey *, const struct sshkey *);
    166 	int (*serialize_public)(const struct sshkey *, struct sshbuf *,
    167 	    enum sshkey_serialize_rep);
    168 	int (*deserialize_public)(const char *, struct sshbuf *,
    169 	    struct sshkey *);
    170 	int (*serialize_private)(const struct sshkey *, struct sshbuf *,
    171 	    enum sshkey_serialize_rep);
    172 	int (*deserialize_private)(const char *, struct sshbuf *,
    173 	    struct sshkey *);
    174 	int (*generate)(struct sshkey *, int);	/* optional */
    175 	int (*copy_public)(const struct sshkey *, struct sshkey *);
    176 	int (*sign)(struct sshkey *, u_char **, size_t *,
    177 	    const u_char *, size_t, const char *,
    178 	    const char *, const char *, u_int); /* optional */
    179 	int (*verify)(const struct sshkey *, const u_char *, size_t,
    180 	    const u_char *, size_t, const char *, u_int,
    181 	    struct sshkey_sig_details **);
    182 };
    183 
    184 struct sshkey_impl {
    185 	const char *name;
    186 	const char *shortname;
    187 	const char *sigalg;
    188 	int type;
    189 	int nid;
    190 	int cert;
    191 	int sigonly;
    192 	int keybits;
    193 	const struct sshkey_impl_funcs *funcs;
    194 };
    195 
    196 struct sshkey	*sshkey_new(int);
    197 void		 sshkey_free(struct sshkey *);
    198 int		 sshkey_equal_public(const struct sshkey *,
    199     const struct sshkey *);
    200 int		 sshkey_equal(const struct sshkey *, const struct sshkey *);
    201 char		*sshkey_fingerprint(const struct sshkey *,
    202     int, enum sshkey_fp_rep);
    203 int		 sshkey_fingerprint_raw(const struct sshkey *k,
    204     int, u_char **retp, size_t *lenp);
    205 const char	*sshkey_type(const struct sshkey *);
    206 const char	*sshkey_cert_type(const struct sshkey *);
    207 int		 sshkey_format_text(const struct sshkey *, struct sshbuf *);
    208 int		 sshkey_write(const struct sshkey *, FILE *);
    209 int		 sshkey_read(struct sshkey *, char **);
    210 u_int		 sshkey_size(const struct sshkey *);
    211 
    212 int		 sshkey_generate(int type, u_int bits, struct sshkey **keyp);
    213 int		 sshkey_from_private(const struct sshkey *, struct sshkey **);
    214 
    215 int		 sshkey_is_shielded(struct sshkey *);
    216 int		 sshkey_shield_private(struct sshkey *);
    217 int		 sshkey_unshield_private(struct sshkey *);
    218 
    219 int	 sshkey_type_from_name(const char *);
    220 int	 sshkey_is_cert(const struct sshkey *);
    221 int	 sshkey_is_sk(const struct sshkey *);
    222 int	 sshkey_type_is_cert(int);
    223 int	 sshkey_type_plain(int);
    224 
    225 /* Returns non-zero if key name match sigalgs pattern list. (handles RSA) */
    226 int	 sshkey_match_keyname_to_sigalgs(const char *, const char *);
    227 
    228 int	 sshkey_to_certified(struct sshkey *);
    229 int	 sshkey_drop_cert(struct sshkey *);
    230 int	 sshkey_cert_copy(const struct sshkey *, struct sshkey *);
    231 int	 sshkey_cert_check_authority(const struct sshkey *, int, int, int,
    232     uint64_t, const char *, const char **);
    233 int	 sshkey_cert_check_authority_now(const struct sshkey *, int, int, int,
    234     const char *, const char **);
    235 int	 sshkey_cert_check_host(const struct sshkey *, const char *,
    236     int , const char *, const char **);
    237 size_t	 sshkey_format_cert_validity(const struct sshkey_cert *,
    238     char *, size_t) __attribute__((__bounded__(__string__, 2, 3)));
    239 int	 sshkey_check_cert_sigtype(const struct sshkey *, const char *);
    240 
    241 int	 sshkey_certify(struct sshkey *, struct sshkey *,
    242     const char *, const char *, const char *);
    243 /* Variant allowing use of a custom signature function (e.g. for ssh-agent) */
    244 typedef int sshkey_certify_signer(struct sshkey *, u_char **, size_t *,
    245     const u_char *, size_t, const char *, const char *, const char *,
    246     u_int, void *);
    247 int	 sshkey_certify_custom(struct sshkey *, struct sshkey *, const char *,
    248     const char *, const char *, sshkey_certify_signer *, void *);
    249 
    250 int		 sshkey_ecdsa_nid_from_name(const char *);
    251 int		 sshkey_curve_name_to_nid(const char *);
    252 const char *	 sshkey_curve_nid_to_name(int);
    253 u_int		 sshkey_curve_nid_to_bits(int);
    254 int		 sshkey_ecdsa_bits_to_nid(int);
    255 int		 sshkey_ecdsa_key_to_nid(EC_KEY *);
    256 int		 sshkey_ec_nid_to_hash_alg(int nid);
    257 int		 sshkey_ec_validate_public(const EC_GROUP *, const EC_POINT *);
    258 int		 sshkey_ec_validate_private(const EC_KEY *);
    259 const char	*sshkey_ssh_name(const struct sshkey *);
    260 const char	*sshkey_ssh_name_plain(const struct sshkey *);
    261 int		 sshkey_names_valid2(const char *, int, int);
    262 char		*sshkey_alg_list(int, int, int, char);
    263 
    264 int	 sshkey_from_blob(const u_char *, size_t, struct sshkey **);
    265 int	 sshkey_fromb(struct sshbuf *, struct sshkey **);
    266 int	 sshkey_froms(struct sshbuf *, struct sshkey **);
    267 int	 sshkey_to_blob(const struct sshkey *, u_char **, size_t *);
    268 int	 sshkey_to_base64(const struct sshkey *, char **);
    269 int	 sshkey_putb(const struct sshkey *, struct sshbuf *);
    270 int	 sshkey_puts(const struct sshkey *, struct sshbuf *);
    271 int	 sshkey_puts_opts(const struct sshkey *, struct sshbuf *,
    272     enum sshkey_serialize_rep);
    273 int	 sshkey_plain_to_blob(const struct sshkey *, u_char **, size_t *);
    274 int	 sshkey_putb_plain(const struct sshkey *, struct sshbuf *);
    275 
    276 int	 sshkey_sign(struct sshkey *, u_char **, size_t *,
    277     const u_char *, size_t, const char *, const char *, const char *, u_int);
    278 int	 sshkey_verify(const struct sshkey *, const u_char *, size_t,
    279     const u_char *, size_t, const char *, u_int, struct sshkey_sig_details **);
    280 int	 sshkey_check_sigtype(const u_char *, size_t, const char *);
    281 const char *sshkey_sigalg_by_name(const char *);
    282 int	 sshkey_get_sigtype(const u_char *, size_t, char **);
    283 
    284 /* for debug */
    285 void	sshkey_dump_ec_point(const EC_GROUP *, const EC_POINT *);
    286 void	sshkey_dump_ec_key(const EC_KEY *);
    287 
    288 /* private key parsing and serialisation */
    289 int	sshkey_private_serialize(struct sshkey *key, struct sshbuf *buf);
    290 int	sshkey_private_serialize_opt(struct sshkey *key, struct sshbuf *buf,
    291     enum sshkey_serialize_rep);
    292 int	sshkey_private_deserialize(struct sshbuf *buf,  struct sshkey **keyp);
    293 
    294 /* private key file format parsing and serialisation */
    295 int	sshkey_private_to_fileblob(struct sshkey *key, struct sshbuf *blob,
    296     const char *passphrase, const char *comment,
    297     int format, const char *openssh_format_cipher, int openssh_format_rounds);
    298 int	sshkey_parse_private_fileblob(struct sshbuf *buffer,
    299     const char *passphrase, struct sshkey **keyp, char **commentp);
    300 int	sshkey_parse_private_fileblob_type(struct sshbuf *blob, int type,
    301     const char *passphrase, struct sshkey **keyp, char **commentp);
    302 int	sshkey_parse_pubkey_from_private_fileblob_type(struct sshbuf *blob,
    303     int type, struct sshkey **pubkeyp);
    304 
    305 int sshkey_check_rsa_length(const struct sshkey *, int);
    306 /* XXX should be internal, but used by ssh-keygen */
    307 int ssh_rsa_complete_crt_parameters(struct sshkey *, const BIGNUM *);
    308 
    309 /* stateful keys (e.g. XMSS) */
    310 int	 sshkey_set_filename(struct sshkey *, const char *);
    311 int	 sshkey_enable_maxsign(struct sshkey *, u_int32_t);
    312 u_int32_t sshkey_signatures_left(const struct sshkey *);
    313 int	 sshkey_forward_state(const struct sshkey *, u_int32_t, int);
    314 int	 sshkey_private_serialize_maxsign(struct sshkey *key,
    315     struct sshbuf *buf, u_int32_t maxsign, int);
    316 
    317 void	 sshkey_sig_details_free(struct sshkey_sig_details *);
    318 
    319 #ifdef SSHKEY_INTERNAL
    320 int	sshkey_sk_fields_equal(const struct sshkey *a, const struct sshkey *b);
    321 void	sshkey_sk_cleanup(struct sshkey *k);
    322 int	sshkey_serialize_sk(const struct sshkey *key, struct sshbuf *b);
    323 int	sshkey_copy_public_sk(const struct sshkey *from, struct sshkey *to);
    324 int	sshkey_deserialize_sk(struct sshbuf *b, struct sshkey *key);
    325 int	sshkey_serialize_private_sk(const struct sshkey *key,
    326     struct sshbuf *buf);
    327 int	sshkey_private_deserialize_sk(struct sshbuf *buf, struct sshkey *k);
    328 #ifdef WITH_OPENSSL
    329 int	check_rsa_length(const RSA *rsa); /* XXX remove */
    330 #endif
    331 #endif
    332 
    333 #ifndef WITH_OPENSSL
    334 #undef RSA
    335 #undef DSA
    336 #undef EC_KEY
    337 #undef EC_GROUP
    338 #undef EC_POINT
    339 #endif /* WITH_OPENSSL */
    340 
    341 #endif /* SSHKEY_H */
    342