xref: /openssh-portable/sshkey.h (revision 3b44f251)
1 /* $OpenBSD: sshkey.h,v 1.49 2021/01/26 00:49:30 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 # ifdef OPENSSL_HAS_ECC
35 #  include <openssl/ec.h>
36 #  include <openssl/ecdsa.h>
37 # else /* OPENSSL_HAS_ECC */
38 #  define EC_KEY	void
39 #  define EC_GROUP	void
40 #  define EC_POINT	void
41 # endif /* OPENSSL_HAS_ECC */
42 #define SSH_OPENSSL_VERSION OpenSSL_version(OPENSSL_VERSION)
43 #else /* WITH_OPENSSL */
44 # define BIGNUM		void
45 # define RSA		void
46 # define DSA		void
47 # define EC_KEY		void
48 # define EC_GROUP	void
49 # define EC_POINT	void
50 #define SSH_OPENSSL_VERSION "without OpenSSL"
51 #endif /* WITH_OPENSSL */
52 
53 #define SSH_RSA_MINIMUM_MODULUS_SIZE	1024
54 #define SSH_KEY_MAX_SIGN_DATA_SIZE	(1 << 20)
55 
56 struct sshbuf;
57 
58 /* Key types */
59 enum sshkey_types {
60 	KEY_RSA,
61 	KEY_DSA,
62 	KEY_ECDSA,
63 	KEY_ED25519,
64 	KEY_RSA_CERT,
65 	KEY_DSA_CERT,
66 	KEY_ECDSA_CERT,
67 	KEY_ED25519_CERT,
68 	KEY_XMSS,
69 	KEY_XMSS_CERT,
70 	KEY_ECDSA_SK,
71 	KEY_ECDSA_SK_CERT,
72 	KEY_ED25519_SK,
73 	KEY_ED25519_SK_CERT,
74 	KEY_UNSPEC
75 };
76 
77 /* Default fingerprint hash */
78 #define SSH_FP_HASH_DEFAULT	SSH_DIGEST_SHA256
79 
80 /* Fingerprint representation formats */
81 enum sshkey_fp_rep {
82 	SSH_FP_DEFAULT = 0,
83 	SSH_FP_HEX,
84 	SSH_FP_BASE64,
85 	SSH_FP_BUBBLEBABBLE,
86 	SSH_FP_RANDOMART
87 };
88 
89 /* Private key serialisation formats, used on the wire */
90 enum sshkey_serialize_rep {
91 	SSHKEY_SERIALIZE_DEFAULT = 0,
92 	SSHKEY_SERIALIZE_STATE = 1,	/* only state is serialized */
93 	SSHKEY_SERIALIZE_FULL = 2,	/* include keys for saving to disk */
94 	SSHKEY_SERIALIZE_SHIELD = 3,	/* everything, for encrypting in ram */
95 	SSHKEY_SERIALIZE_INFO = 254,	/* minimal information */
96 };
97 
98 /* Private key disk formats */
99 enum sshkey_private_format {
100 	SSHKEY_PRIVATE_OPENSSH = 0,
101 	SSHKEY_PRIVATE_PEM = 1,
102 	SSHKEY_PRIVATE_PKCS8 = 2,
103 };
104 
105 /* key is stored in external hardware */
106 #define SSHKEY_FLAG_EXT		0x0001
107 
108 #define SSHKEY_CERT_MAX_PRINCIPALS	256
109 /* XXX opaquify? */
110 struct sshkey_cert {
111 	struct sshbuf	*certblob; /* Kept around for use on wire */
112 	u_int		 type; /* SSH2_CERT_TYPE_USER or SSH2_CERT_TYPE_HOST */
113 	u_int64_t	 serial;
114 	char		*key_id;
115 	u_int		 nprincipals;
116 	char		**principals;
117 	u_int64_t	 valid_after, valid_before;
118 	struct sshbuf	*critical;
119 	struct sshbuf	*extensions;
120 	struct sshkey	*signature_key;
121 	char		*signature_type;
122 };
123 
124 /* XXX opaquify? */
125 struct sshkey {
126 	int	 type;
127 	int	 flags;
128 	/* KEY_RSA */
129 	RSA	*rsa;
130 	/* KEY_DSA */
131 	DSA	*dsa;
132 	/* KEY_ECDSA and KEY_ECDSA_SK */
133 	int	 ecdsa_nid;	/* NID of curve */
134 	EC_KEY	*ecdsa;
135 	/* KEY_ED25519 and KEY_ED25519_SK */
136 	u_char	*ed25519_sk;
137 	u_char	*ed25519_pk;
138 	/* KEY_XMSS */
139 	char	*xmss_name;
140 	char	*xmss_filename;	/* for state file updates */
141 	void	*xmss_state;	/* depends on xmss_name, opaque */
142 	u_char	*xmss_sk;
143 	u_char	*xmss_pk;
144 	/* KEY_ECDSA_SK and KEY_ED25519_SK */
145 	char	*sk_application;
146 	uint8_t	sk_flags;
147 	struct sshbuf *sk_key_handle;
148 	struct sshbuf *sk_reserved;
149 	/* Certificates */
150 	struct sshkey_cert *cert;
151 	/* Private key shielding */
152 	u_char	*shielded_private;
153 	size_t	shielded_len;
154 	u_char	*shield_prekey;
155 	size_t	shield_prekey_len;
156 };
157 
158 #define	ED25519_SK_SZ	crypto_sign_ed25519_SECRETKEYBYTES
159 #define	ED25519_PK_SZ	crypto_sign_ed25519_PUBLICKEYBYTES
160 
161 /* Additional fields contained in signature */
162 struct sshkey_sig_details {
163 	uint32_t sk_counter;	/* U2F signature counter */
164 	uint8_t sk_flags;	/* U2F signature flags; see ssh-sk.h */
165 };
166 
167 struct sshkey	*sshkey_new(int);
168 void		 sshkey_free(struct sshkey *);
169 int		 sshkey_equal_public(const struct sshkey *,
170     const struct sshkey *);
171 int		 sshkey_equal(const struct sshkey *, const struct sshkey *);
172 char		*sshkey_fingerprint(const struct sshkey *,
173     int, enum sshkey_fp_rep);
174 int		 sshkey_fingerprint_raw(const struct sshkey *k,
175     int, u_char **retp, size_t *lenp);
176 const char	*sshkey_type(const struct sshkey *);
177 const char	*sshkey_cert_type(const struct sshkey *);
178 int		 sshkey_format_text(const struct sshkey *, struct sshbuf *);
179 int		 sshkey_write(const struct sshkey *, FILE *);
180 int		 sshkey_read(struct sshkey *, char **);
181 u_int		 sshkey_size(const struct sshkey *);
182 
183 int		 sshkey_generate(int type, u_int bits, struct sshkey **keyp);
184 int		 sshkey_from_private(const struct sshkey *, struct sshkey **);
185 
186 int		 sshkey_is_shielded(struct sshkey *);
187 int		 sshkey_shield_private(struct sshkey *);
188 int		 sshkey_unshield_private(struct sshkey *);
189 
190 int	 sshkey_type_from_name(const char *);
191 int	 sshkey_is_cert(const struct sshkey *);
192 int	 sshkey_is_sk(const struct sshkey *);
193 int	 sshkey_type_is_cert(int);
194 int	 sshkey_type_plain(int);
195 int	 sshkey_to_certified(struct sshkey *);
196 int	 sshkey_drop_cert(struct sshkey *);
197 int	 sshkey_cert_copy(const struct sshkey *, struct sshkey *);
198 int	 sshkey_cert_check_authority(const struct sshkey *, int, int, int,
199     const char *, const char **);
200 int	 sshkey_cert_check_host(const struct sshkey *, const char *,
201     int , const char *, const char **);
202 size_t	 sshkey_format_cert_validity(const struct sshkey_cert *,
203     char *, size_t) __attribute__((__bounded__(__string__, 2, 3)));
204 int	 sshkey_check_cert_sigtype(const struct sshkey *, const char *);
205 
206 int	 sshkey_certify(struct sshkey *, struct sshkey *,
207     const char *, const char *, const char *);
208 /* Variant allowing use of a custom signature function (e.g. for ssh-agent) */
209 typedef int sshkey_certify_signer(struct sshkey *, u_char **, size_t *,
210     const u_char *, size_t, const char *, const char *, const char *,
211     u_int, void *);
212 int	 sshkey_certify_custom(struct sshkey *, struct sshkey *, const char *,
213     const char *, const char *, sshkey_certify_signer *, void *);
214 
215 int		 sshkey_ecdsa_nid_from_name(const char *);
216 int		 sshkey_curve_name_to_nid(const char *);
217 const char *	 sshkey_curve_nid_to_name(int);
218 u_int		 sshkey_curve_nid_to_bits(int);
219 int		 sshkey_ecdsa_bits_to_nid(int);
220 int		 sshkey_ecdsa_key_to_nid(EC_KEY *);
221 int		 sshkey_ec_nid_to_hash_alg(int nid);
222 int		 sshkey_ec_validate_public(const EC_GROUP *, const EC_POINT *);
223 int		 sshkey_ec_validate_private(const EC_KEY *);
224 const char	*sshkey_ssh_name(const struct sshkey *);
225 const char	*sshkey_ssh_name_plain(const struct sshkey *);
226 int		 sshkey_names_valid2(const char *, int);
227 char		*sshkey_alg_list(int, int, int, char);
228 
229 int	 sshkey_from_blob(const u_char *, size_t, struct sshkey **);
230 int	 sshkey_fromb(struct sshbuf *, struct sshkey **);
231 int	 sshkey_froms(struct sshbuf *, struct sshkey **);
232 int	 sshkey_to_blob(const struct sshkey *, u_char **, size_t *);
233 int	 sshkey_to_base64(const struct sshkey *, char **);
234 int	 sshkey_putb(const struct sshkey *, struct sshbuf *);
235 int	 sshkey_puts(const struct sshkey *, struct sshbuf *);
236 int	 sshkey_puts_opts(const struct sshkey *, struct sshbuf *,
237     enum sshkey_serialize_rep);
238 int	 sshkey_plain_to_blob(const struct sshkey *, u_char **, size_t *);
239 int	 sshkey_putb_plain(const struct sshkey *, struct sshbuf *);
240 
241 int	 sshkey_sign(struct sshkey *, u_char **, size_t *,
242     const u_char *, size_t, const char *, const char *, const char *, u_int);
243 int	 sshkey_verify(const struct sshkey *, const u_char *, size_t,
244     const u_char *, size_t, const char *, u_int, struct sshkey_sig_details **);
245 int	 sshkey_check_sigtype(const u_char *, size_t, const char *);
246 const char *sshkey_sigalg_by_name(const char *);
247 int	 sshkey_get_sigtype(const u_char *, size_t, char **);
248 
249 /* for debug */
250 void	sshkey_dump_ec_point(const EC_GROUP *, const EC_POINT *);
251 void	sshkey_dump_ec_key(const EC_KEY *);
252 
253 /* private key parsing and serialisation */
254 int	sshkey_private_serialize(struct sshkey *key, struct sshbuf *buf);
255 int	sshkey_private_serialize_opt(struct sshkey *key, struct sshbuf *buf,
256     enum sshkey_serialize_rep);
257 int	sshkey_private_deserialize(struct sshbuf *buf,  struct sshkey **keyp);
258 
259 /* private key file format parsing and serialisation */
260 int	sshkey_private_to_fileblob(struct sshkey *key, struct sshbuf *blob,
261     const char *passphrase, const char *comment,
262     int format, const char *openssh_format_cipher, int openssh_format_rounds);
263 int	sshkey_parse_private_fileblob(struct sshbuf *buffer,
264     const char *passphrase, struct sshkey **keyp, char **commentp);
265 int	sshkey_parse_private_fileblob_type(struct sshbuf *blob, int type,
266     const char *passphrase, struct sshkey **keyp, char **commentp);
267 int	sshkey_parse_pubkey_from_private_fileblob_type(struct sshbuf *blob,
268     int type, struct sshkey **pubkeyp);
269 
270 /* XXX should be internal, but used by ssh-keygen */
271 int ssh_rsa_complete_crt_parameters(struct sshkey *, const BIGNUM *);
272 
273 /* stateful keys (e.g. XMSS) */
274 int	 sshkey_set_filename(struct sshkey *, const char *);
275 int	 sshkey_enable_maxsign(struct sshkey *, u_int32_t);
276 u_int32_t sshkey_signatures_left(const struct sshkey *);
277 int	 sshkey_forward_state(const struct sshkey *, u_int32_t, int);
278 int	 sshkey_private_serialize_maxsign(struct sshkey *key,
279     struct sshbuf *buf, u_int32_t maxsign, int);
280 
281 void	 sshkey_sig_details_free(struct sshkey_sig_details *);
282 
283 #ifdef SSHKEY_INTERNAL
284 int ssh_rsa_sign(const struct sshkey *key,
285     u_char **sigp, size_t *lenp, const u_char *data, size_t datalen,
286     const char *ident);
287 int ssh_rsa_verify(const struct sshkey *key,
288     const u_char *sig, size_t siglen, const u_char *data, size_t datalen,
289     const char *alg);
290 int ssh_dss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
291     const u_char *data, size_t datalen, u_int compat);
292 int ssh_dss_verify(const struct sshkey *key,
293     const u_char *signature, size_t signaturelen,
294     const u_char *data, size_t datalen, u_int compat);
295 int ssh_ecdsa_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
296     const u_char *data, size_t datalen, u_int compat);
297 int ssh_ecdsa_verify(const struct sshkey *key,
298     const u_char *signature, size_t signaturelen,
299     const u_char *data, size_t datalen, u_int compat);
300 int ssh_ecdsa_sk_verify(const struct sshkey *key,
301     const u_char *signature, size_t signaturelen,
302     const u_char *data, size_t datalen, u_int compat,
303     struct sshkey_sig_details **detailsp);
304 int ssh_ed25519_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
305     const u_char *data, size_t datalen, u_int compat);
306 int ssh_ed25519_verify(const struct sshkey *key,
307     const u_char *signature, size_t signaturelen,
308     const u_char *data, size_t datalen, u_int compat);
309 int ssh_ed25519_sk_verify(const struct sshkey *key,
310     const u_char *signature, size_t signaturelen,
311     const u_char *data, size_t datalen, u_int compat,
312     struct sshkey_sig_details **detailsp);
313 int ssh_xmss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
314     const u_char *data, size_t datalen, u_int compat);
315 int ssh_xmss_verify(const struct sshkey *key,
316     const u_char *signature, size_t signaturelen,
317     const u_char *data, size_t datalen, u_int compat);
318 #endif
319 
320 #if !defined(WITH_OPENSSL)
321 # undef RSA
322 # undef DSA
323 # undef EC_KEY
324 # undef EC_GROUP
325 # undef EC_POINT
326 #elif !defined(OPENSSL_HAS_ECC)
327 # undef EC_KEY
328 # undef EC_GROUP
329 # undef EC_POINT
330 #endif
331 
332 #endif /* SSHKEY_H */
333