xref: /openssh-portable/sshkey.h (revision 611073fb)
1 /* $OpenBSD: sshkey.h,v 1.42 2019/12/13 19:11:14 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 #else /* WITH_OPENSSL */
43 # define BIGNUM		void
44 # define RSA		void
45 # define DSA		void
46 # define EC_KEY		void
47 # define EC_GROUP	void
48 # define EC_POINT	void
49 #endif /* WITH_OPENSSL */
50 
51 #define SSH_RSA_MINIMUM_MODULUS_SIZE	1024
52 #define SSH_KEY_MAX_SIGN_DATA_SIZE	(1 << 20)
53 
54 /* Version of protocol expected from ssh-sk-helper */
55 #define SSH_SK_HELPER_VERSION		2
56 
57 /* ssh-sk-helper messages */
58 #define SSH_SK_HELPER_SIGN		1
59 #define SSH_SK_HELPER_ENROLL		2
60 
61 struct sshbuf;
62 
63 /* Key types */
64 enum sshkey_types {
65 	KEY_RSA,
66 	KEY_DSA,
67 	KEY_ECDSA,
68 	KEY_ED25519,
69 	KEY_RSA_CERT,
70 	KEY_DSA_CERT,
71 	KEY_ECDSA_CERT,
72 	KEY_ED25519_CERT,
73 	KEY_XMSS,
74 	KEY_XMSS_CERT,
75 	KEY_ECDSA_SK,
76 	KEY_ECDSA_SK_CERT,
77 	KEY_ED25519_SK,
78 	KEY_ED25519_SK_CERT,
79 	KEY_UNSPEC
80 };
81 
82 /* Default fingerprint hash */
83 #define SSH_FP_HASH_DEFAULT	SSH_DIGEST_SHA256
84 
85 /* Fingerprint representation formats */
86 enum sshkey_fp_rep {
87 	SSH_FP_DEFAULT = 0,
88 	SSH_FP_HEX,
89 	SSH_FP_BASE64,
90 	SSH_FP_BUBBLEBABBLE,
91 	SSH_FP_RANDOMART
92 };
93 
94 /* Private key serialisation formats, used on the wire */
95 enum sshkey_serialize_rep {
96 	SSHKEY_SERIALIZE_DEFAULT = 0,
97 	SSHKEY_SERIALIZE_STATE = 1,	/* only state is serialized */
98 	SSHKEY_SERIALIZE_FULL = 2,	/* include keys for saving to disk */
99 	SSHKEY_SERIALIZE_SHIELD = 3,	/* everything, for encrypting in ram */
100 	SSHKEY_SERIALIZE_INFO = 254,	/* minimal information */
101 };
102 
103 /* Private key disk formats */
104 enum sshkey_private_format {
105 	SSHKEY_PRIVATE_OPENSSH = 0,
106 	SSHKEY_PRIVATE_PEM = 1,
107 	SSHKEY_PRIVATE_PKCS8 = 2,
108 };
109 
110 /* key is stored in external hardware */
111 #define SSHKEY_FLAG_EXT		0x0001
112 
113 #define SSHKEY_CERT_MAX_PRINCIPALS	256
114 /* XXX opaquify? */
115 struct sshkey_cert {
116 	struct sshbuf	*certblob; /* Kept around for use on wire */
117 	u_int		 type; /* SSH2_CERT_TYPE_USER or SSH2_CERT_TYPE_HOST */
118 	u_int64_t	 serial;
119 	char		*key_id;
120 	u_int		 nprincipals;
121 	char		**principals;
122 	u_int64_t	 valid_after, valid_before;
123 	struct sshbuf	*critical;
124 	struct sshbuf	*extensions;
125 	struct sshkey	*signature_key;
126 	char		*signature_type;
127 };
128 
129 /* XXX opaquify? */
130 struct sshkey {
131 	int	 type;
132 	int	 flags;
133 	/* KEY_RSA */
134 	RSA	*rsa;
135 	/* KEY_DSA */
136 	DSA	*dsa;
137 	/* KEY_ECDSA and KEY_ECDSA_SK */
138 	int	 ecdsa_nid;	/* NID of curve */
139 	EC_KEY	*ecdsa;
140 	/* KEY_ED25519 and KEY_ED25519_SK */
141 	u_char	*ed25519_sk;
142 	u_char	*ed25519_pk;
143 	/* KEY_XMSS */
144 	char	*xmss_name;
145 	char	*xmss_filename;	/* for state file updates */
146 	void	*xmss_state;	/* depends on xmss_name, opaque */
147 	u_char	*xmss_sk;
148 	u_char	*xmss_pk;
149 	/* KEY_ECDSA_SK and KEY_ED25519_SK */
150 	char	*sk_application;
151 	uint8_t	sk_flags;
152 	struct sshbuf *sk_key_handle;
153 	struct sshbuf *sk_reserved;
154 	/* Certificates */
155 	struct sshkey_cert *cert;
156 	/* Private key shielding */
157 	u_char	*shielded_private;
158 	size_t	shielded_len;
159 	u_char	*shield_prekey;
160 	size_t	shield_prekey_len;
161 };
162 
163 #define	ED25519_SK_SZ	crypto_sign_ed25519_SECRETKEYBYTES
164 #define	ED25519_PK_SZ	crypto_sign_ed25519_PUBLICKEYBYTES
165 
166 /* Additional fields contained in signature */
167 struct sshkey_sig_details {
168 	uint32_t sk_counter;	/* U2F signature counter */
169 	uint8_t sk_flags;	/* U2F signature flags; see ssh-sk.h */
170 };
171 
172 struct sshkey	*sshkey_new(int);
173 void		 sshkey_free(struct sshkey *);
174 int		 sshkey_equal_public(const struct sshkey *,
175     const struct sshkey *);
176 int		 sshkey_equal(const struct sshkey *, const struct sshkey *);
177 char		*sshkey_fingerprint(const struct sshkey *,
178     int, enum sshkey_fp_rep);
179 int		 sshkey_fingerprint_raw(const struct sshkey *k,
180     int, u_char **retp, size_t *lenp);
181 const char	*sshkey_type(const struct sshkey *);
182 const char	*sshkey_cert_type(const struct sshkey *);
183 int		 sshkey_format_text(const struct sshkey *, struct sshbuf *);
184 int		 sshkey_write(const struct sshkey *, FILE *);
185 int		 sshkey_read(struct sshkey *, char **);
186 u_int		 sshkey_size(const struct sshkey *);
187 
188 int		 sshkey_generate(int type, u_int bits, struct sshkey **keyp);
189 int		 sshkey_from_private(const struct sshkey *, struct sshkey **);
190 
191 int		 sshkey_is_shielded(struct sshkey *);
192 int		 sshkey_shield_private(struct sshkey *);
193 int		 sshkey_unshield_private(struct sshkey *);
194 
195 int	 sshkey_type_from_name(const char *);
196 int	 sshkey_is_cert(const struct sshkey *);
197 int	 sshkey_is_sk(const struct sshkey *);
198 int	 sshkey_type_is_cert(int);
199 int	 sshkey_type_plain(int);
200 int	 sshkey_to_certified(struct sshkey *);
201 int	 sshkey_drop_cert(struct sshkey *);
202 int	 sshkey_cert_copy(const struct sshkey *, struct sshkey *);
203 int	 sshkey_cert_check_authority(const struct sshkey *, int, int,
204     const char *, const char **);
205 size_t	 sshkey_format_cert_validity(const struct sshkey_cert *,
206     char *, size_t) __attribute__((__bounded__(__string__, 2, 3)));
207 int	 sshkey_check_cert_sigtype(const struct sshkey *, const char *);
208 
209 int	 sshkey_certify(struct sshkey *, struct sshkey *,
210     const char *, const char *);
211 /* Variant allowing use of a custom signature function (e.g. for ssh-agent) */
212 typedef int sshkey_certify_signer(struct sshkey *, u_char **, size_t *,
213     const u_char *, size_t, const char *, const char *, u_int, void *);
214 int	 sshkey_certify_custom(struct sshkey *, struct sshkey *, const char *,
215     const char *, sshkey_certify_signer *, void *);
216 
217 int		 sshkey_ecdsa_nid_from_name(const char *);
218 int		 sshkey_curve_name_to_nid(const char *);
219 const char *	 sshkey_curve_nid_to_name(int);
220 u_int		 sshkey_curve_nid_to_bits(int);
221 int		 sshkey_ecdsa_bits_to_nid(int);
222 int		 sshkey_ecdsa_key_to_nid(EC_KEY *);
223 int		 sshkey_ec_nid_to_hash_alg(int nid);
224 int		 sshkey_ec_validate_public(const EC_GROUP *, const EC_POINT *);
225 int		 sshkey_ec_validate_private(const EC_KEY *);
226 const char	*sshkey_ssh_name(const struct sshkey *);
227 const char	*sshkey_ssh_name_plain(const struct sshkey *);
228 int		 sshkey_names_valid2(const char *, int);
229 char		*sshkey_alg_list(int, int, int, char);
230 
231 int	 sshkey_from_blob(const u_char *, size_t, struct sshkey **);
232 int	 sshkey_fromb(struct sshbuf *, struct sshkey **);
233 int	 sshkey_froms(struct sshbuf *, struct sshkey **);
234 int	 sshkey_to_blob(const struct sshkey *, u_char **, size_t *);
235 int	 sshkey_to_base64(const struct sshkey *, char **);
236 int	 sshkey_putb(const struct sshkey *, struct sshbuf *);
237 int	 sshkey_puts(const struct sshkey *, struct sshbuf *);
238 int	 sshkey_puts_opts(const struct sshkey *, struct sshbuf *,
239     enum sshkey_serialize_rep);
240 int	 sshkey_plain_to_blob(const struct sshkey *, u_char **, size_t *);
241 int	 sshkey_putb_plain(const struct sshkey *, struct sshbuf *);
242 
243 int	 sshkey_sign(struct sshkey *, u_char **, size_t *,
244     const u_char *, size_t, const char *, const char *, u_int);
245 int	 sshkey_verify(const struct sshkey *, const u_char *, size_t,
246     const u_char *, size_t, const char *, u_int, struct sshkey_sig_details **);
247 int	 sshkey_check_sigtype(const u_char *, size_t, const char *);
248 const char *sshkey_sigalg_by_name(const char *);
249 int	 sshkey_get_sigtype(const u_char *, size_t, char **);
250 
251 /* for debug */
252 void	sshkey_dump_ec_point(const EC_GROUP *, const EC_POINT *);
253 void	sshkey_dump_ec_key(const EC_KEY *);
254 
255 /* private key parsing and serialisation */
256 int	sshkey_private_serialize(struct sshkey *key, struct sshbuf *buf);
257 int	sshkey_private_serialize_opt(struct sshkey *key, struct sshbuf *buf,
258     enum sshkey_serialize_rep);
259 int	sshkey_private_deserialize(struct sshbuf *buf,  struct sshkey **keyp);
260 
261 /* private key file format parsing and serialisation */
262 int	sshkey_private_to_fileblob(struct sshkey *key, struct sshbuf *blob,
263     const char *passphrase, const char *comment,
264     int format, const char *openssh_format_cipher, int openssh_format_rounds);
265 int	sshkey_parse_private_fileblob(struct sshbuf *buffer,
266     const char *passphrase, struct sshkey **keyp, char **commentp);
267 int	sshkey_parse_private_fileblob_type(struct sshbuf *blob, int type,
268     const char *passphrase, struct sshkey **keyp, char **commentp);
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 #ifdef NO_ATTRIBUTE_ON_PROTOTYPE_ARGS
275 typedef void sshkey_printfn(const char *, ...);
276 #else
277 typedef void sshkey_printfn(const char *, ...) __attribute__((format(printf, 1, 2)));
278 #endif
279 int	 sshkey_set_filename(struct sshkey *, const char *);
280 int	 sshkey_enable_maxsign(struct sshkey *, u_int32_t);
281 u_int32_t sshkey_signatures_left(const struct sshkey *);
282 int	 sshkey_forward_state(const struct sshkey *, u_int32_t, sshkey_printfn *);
283 int	 sshkey_private_serialize_maxsign(struct sshkey *key, struct sshbuf *buf,
284     u_int32_t maxsign, sshkey_printfn *pr);
285 
286 void	 sshkey_sig_details_free(struct sshkey_sig_details *);
287 
288 #ifdef SSHKEY_INTERNAL
289 int ssh_rsa_sign(const struct sshkey *key,
290     u_char **sigp, size_t *lenp, const u_char *data, size_t datalen,
291     const char *ident);
292 int ssh_rsa_verify(const struct sshkey *key,
293     const u_char *sig, size_t siglen, const u_char *data, size_t datalen,
294     const char *alg);
295 int ssh_dss_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_dss_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_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
301     const u_char *data, size_t datalen, u_int compat);
302 int ssh_ecdsa_verify(const struct sshkey *key,
303     const u_char *signature, size_t signaturelen,
304     const u_char *data, size_t datalen, u_int compat);
305 int ssh_ecdsa_sk_verify(const struct sshkey *key,
306     const u_char *signature, size_t signaturelen,
307     const u_char *data, size_t datalen, u_int compat,
308     struct sshkey_sig_details **detailsp);
309 int ssh_ed25519_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
310     const u_char *data, size_t datalen, u_int compat);
311 int ssh_ed25519_verify(const struct sshkey *key,
312     const u_char *signature, size_t signaturelen,
313     const u_char *data, size_t datalen, u_int compat);
314 int ssh_ed25519_sk_verify(const struct sshkey *key,
315     const u_char *signature, size_t signaturelen,
316     const u_char *data, size_t datalen, u_int compat,
317     struct sshkey_sig_details **detailsp);
318 int ssh_xmss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
319     const u_char *data, size_t datalen, u_int compat);
320 int ssh_xmss_verify(const struct sshkey *key,
321     const u_char *signature, size_t signaturelen,
322     const u_char *data, size_t datalen, u_int compat);
323 #endif
324 
325 #if !defined(WITH_OPENSSL)
326 # undef RSA
327 # undef DSA
328 # undef EC_KEY
329 # undef EC_GROUP
330 # undef EC_POINT
331 #elif !defined(OPENSSL_HAS_ECC)
332 # undef EC_KEY
333 # undef EC_GROUP
334 # undef EC_POINT
335 #endif
336 
337 #endif /* SSHKEY_H */
338