xref: /openssh-portable/sshkey.h (revision 27753a8e)
1 /* $OpenBSD: sshkey.h,v 1.43 2019/12/30 09:21:59 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 #define SSH_SK_HELPER_LOAD_RESIDENT	3
61 
62 struct sshbuf;
63 
64 /* Key types */
65 enum sshkey_types {
66 	KEY_RSA,
67 	KEY_DSA,
68 	KEY_ECDSA,
69 	KEY_ED25519,
70 	KEY_RSA_CERT,
71 	KEY_DSA_CERT,
72 	KEY_ECDSA_CERT,
73 	KEY_ED25519_CERT,
74 	KEY_XMSS,
75 	KEY_XMSS_CERT,
76 	KEY_ECDSA_SK,
77 	KEY_ECDSA_SK_CERT,
78 	KEY_ED25519_SK,
79 	KEY_ED25519_SK_CERT,
80 	KEY_UNSPEC
81 };
82 
83 /* Default fingerprint hash */
84 #define SSH_FP_HASH_DEFAULT	SSH_DIGEST_SHA256
85 
86 /* Fingerprint representation formats */
87 enum sshkey_fp_rep {
88 	SSH_FP_DEFAULT = 0,
89 	SSH_FP_HEX,
90 	SSH_FP_BASE64,
91 	SSH_FP_BUBBLEBABBLE,
92 	SSH_FP_RANDOMART
93 };
94 
95 /* Private key serialisation formats, used on the wire */
96 enum sshkey_serialize_rep {
97 	SSHKEY_SERIALIZE_DEFAULT = 0,
98 	SSHKEY_SERIALIZE_STATE = 1,	/* only state is serialized */
99 	SSHKEY_SERIALIZE_FULL = 2,	/* include keys for saving to disk */
100 	SSHKEY_SERIALIZE_SHIELD = 3,	/* everything, for encrypting in ram */
101 	SSHKEY_SERIALIZE_INFO = 254,	/* minimal information */
102 };
103 
104 /* Private key disk formats */
105 enum sshkey_private_format {
106 	SSHKEY_PRIVATE_OPENSSH = 0,
107 	SSHKEY_PRIVATE_PEM = 1,
108 	SSHKEY_PRIVATE_PKCS8 = 2,
109 };
110 
111 /* key is stored in external hardware */
112 #define SSHKEY_FLAG_EXT		0x0001
113 
114 #define SSHKEY_CERT_MAX_PRINCIPALS	256
115 /* XXX opaquify? */
116 struct sshkey_cert {
117 	struct sshbuf	*certblob; /* Kept around for use on wire */
118 	u_int		 type; /* SSH2_CERT_TYPE_USER or SSH2_CERT_TYPE_HOST */
119 	u_int64_t	 serial;
120 	char		*key_id;
121 	u_int		 nprincipals;
122 	char		**principals;
123 	u_int64_t	 valid_after, valid_before;
124 	struct sshbuf	*critical;
125 	struct sshbuf	*extensions;
126 	struct sshkey	*signature_key;
127 	char		*signature_type;
128 };
129 
130 /* XXX opaquify? */
131 struct sshkey {
132 	int	 type;
133 	int	 flags;
134 	/* KEY_RSA */
135 	RSA	*rsa;
136 	/* KEY_DSA */
137 	DSA	*dsa;
138 	/* KEY_ECDSA and KEY_ECDSA_SK */
139 	int	 ecdsa_nid;	/* NID of curve */
140 	EC_KEY	*ecdsa;
141 	/* KEY_ED25519 and KEY_ED25519_SK */
142 	u_char	*ed25519_sk;
143 	u_char	*ed25519_pk;
144 	/* KEY_XMSS */
145 	char	*xmss_name;
146 	char	*xmss_filename;	/* for state file updates */
147 	void	*xmss_state;	/* depends on xmss_name, opaque */
148 	u_char	*xmss_sk;
149 	u_char	*xmss_pk;
150 	/* KEY_ECDSA_SK and KEY_ED25519_SK */
151 	char	*sk_application;
152 	uint8_t	sk_flags;
153 	struct sshbuf *sk_key_handle;
154 	struct sshbuf *sk_reserved;
155 	/* Certificates */
156 	struct sshkey_cert *cert;
157 	/* Private key shielding */
158 	u_char	*shielded_private;
159 	size_t	shielded_len;
160 	u_char	*shield_prekey;
161 	size_t	shield_prekey_len;
162 };
163 
164 #define	ED25519_SK_SZ	crypto_sign_ed25519_SECRETKEYBYTES
165 #define	ED25519_PK_SZ	crypto_sign_ed25519_PUBLICKEYBYTES
166 
167 /* Additional fields contained in signature */
168 struct sshkey_sig_details {
169 	uint32_t sk_counter;	/* U2F signature counter */
170 	uint8_t sk_flags;	/* U2F signature flags; see ssh-sk.h */
171 };
172 
173 struct sshkey	*sshkey_new(int);
174 void		 sshkey_free(struct sshkey *);
175 int		 sshkey_equal_public(const struct sshkey *,
176     const struct sshkey *);
177 int		 sshkey_equal(const struct sshkey *, const struct sshkey *);
178 char		*sshkey_fingerprint(const struct sshkey *,
179     int, enum sshkey_fp_rep);
180 int		 sshkey_fingerprint_raw(const struct sshkey *k,
181     int, u_char **retp, size_t *lenp);
182 const char	*sshkey_type(const struct sshkey *);
183 const char	*sshkey_cert_type(const struct sshkey *);
184 int		 sshkey_format_text(const struct sshkey *, struct sshbuf *);
185 int		 sshkey_write(const struct sshkey *, FILE *);
186 int		 sshkey_read(struct sshkey *, char **);
187 u_int		 sshkey_size(const struct sshkey *);
188 
189 int		 sshkey_generate(int type, u_int bits, struct sshkey **keyp);
190 int		 sshkey_from_private(const struct sshkey *, struct sshkey **);
191 
192 int		 sshkey_is_shielded(struct sshkey *);
193 int		 sshkey_shield_private(struct sshkey *);
194 int		 sshkey_unshield_private(struct sshkey *);
195 
196 int	 sshkey_type_from_name(const char *);
197 int	 sshkey_is_cert(const struct sshkey *);
198 int	 sshkey_is_sk(const struct sshkey *);
199 int	 sshkey_type_is_cert(int);
200 int	 sshkey_type_plain(int);
201 int	 sshkey_to_certified(struct sshkey *);
202 int	 sshkey_drop_cert(struct sshkey *);
203 int	 sshkey_cert_copy(const struct sshkey *, struct sshkey *);
204 int	 sshkey_cert_check_authority(const struct sshkey *, int, int,
205     const char *, const char **);
206 size_t	 sshkey_format_cert_validity(const struct sshkey_cert *,
207     char *, size_t) __attribute__((__bounded__(__string__, 2, 3)));
208 int	 sshkey_check_cert_sigtype(const struct sshkey *, const char *);
209 
210 int	 sshkey_certify(struct sshkey *, struct sshkey *,
211     const char *, const char *);
212 /* Variant allowing use of a custom signature function (e.g. for ssh-agent) */
213 typedef int sshkey_certify_signer(struct sshkey *, u_char **, size_t *,
214     const u_char *, size_t, const char *, const char *, u_int, void *);
215 int	 sshkey_certify_custom(struct sshkey *, struct sshkey *, const char *,
216     const char *, sshkey_certify_signer *, void *);
217 
218 int		 sshkey_ecdsa_nid_from_name(const char *);
219 int		 sshkey_curve_name_to_nid(const char *);
220 const char *	 sshkey_curve_nid_to_name(int);
221 u_int		 sshkey_curve_nid_to_bits(int);
222 int		 sshkey_ecdsa_bits_to_nid(int);
223 int		 sshkey_ecdsa_key_to_nid(EC_KEY *);
224 int		 sshkey_ec_nid_to_hash_alg(int nid);
225 int		 sshkey_ec_validate_public(const EC_GROUP *, const EC_POINT *);
226 int		 sshkey_ec_validate_private(const EC_KEY *);
227 const char	*sshkey_ssh_name(const struct sshkey *);
228 const char	*sshkey_ssh_name_plain(const struct sshkey *);
229 int		 sshkey_names_valid2(const char *, int);
230 char		*sshkey_alg_list(int, int, int, char);
231 
232 int	 sshkey_from_blob(const u_char *, size_t, struct sshkey **);
233 int	 sshkey_fromb(struct sshbuf *, struct sshkey **);
234 int	 sshkey_froms(struct sshbuf *, struct sshkey **);
235 int	 sshkey_to_blob(const struct sshkey *, u_char **, size_t *);
236 int	 sshkey_to_base64(const struct sshkey *, char **);
237 int	 sshkey_putb(const struct sshkey *, struct sshbuf *);
238 int	 sshkey_puts(const struct sshkey *, struct sshbuf *);
239 int	 sshkey_puts_opts(const struct sshkey *, struct sshbuf *,
240     enum sshkey_serialize_rep);
241 int	 sshkey_plain_to_blob(const struct sshkey *, u_char **, size_t *);
242 int	 sshkey_putb_plain(const struct sshkey *, struct sshbuf *);
243 
244 int	 sshkey_sign(struct sshkey *, u_char **, size_t *,
245     const u_char *, size_t, const char *, const char *, u_int);
246 int	 sshkey_verify(const struct sshkey *, const u_char *, size_t,
247     const u_char *, size_t, const char *, u_int, struct sshkey_sig_details **);
248 int	 sshkey_check_sigtype(const u_char *, size_t, const char *);
249 const char *sshkey_sigalg_by_name(const char *);
250 int	 sshkey_get_sigtype(const u_char *, size_t, char **);
251 
252 /* for debug */
253 void	sshkey_dump_ec_point(const EC_GROUP *, const EC_POINT *);
254 void	sshkey_dump_ec_key(const EC_KEY *);
255 
256 /* private key parsing and serialisation */
257 int	sshkey_private_serialize(struct sshkey *key, struct sshbuf *buf);
258 int	sshkey_private_serialize_opt(struct sshkey *key, struct sshbuf *buf,
259     enum sshkey_serialize_rep);
260 int	sshkey_private_deserialize(struct sshbuf *buf,  struct sshkey **keyp);
261 
262 /* private key file format parsing and serialisation */
263 int	sshkey_private_to_fileblob(struct sshkey *key, struct sshbuf *blob,
264     const char *passphrase, const char *comment,
265     int format, const char *openssh_format_cipher, int openssh_format_rounds);
266 int	sshkey_parse_private_fileblob(struct sshbuf *buffer,
267     const char *passphrase, struct sshkey **keyp, char **commentp);
268 int	sshkey_parse_private_fileblob_type(struct sshbuf *blob, int type,
269     const char *passphrase, struct sshkey **keyp, char **commentp);
270 
271 /* XXX should be internal, but used by ssh-keygen */
272 int ssh_rsa_complete_crt_parameters(struct sshkey *, const BIGNUM *);
273 
274 /* stateful keys (e.g. XMSS) */
275 #ifdef NO_ATTRIBUTE_ON_PROTOTYPE_ARGS
276 typedef void sshkey_printfn(const char *, ...);
277 #else
278 typedef void sshkey_printfn(const char *, ...) __attribute__((format(printf, 1, 2)));
279 #endif
280 int	 sshkey_set_filename(struct sshkey *, const char *);
281 int	 sshkey_enable_maxsign(struct sshkey *, u_int32_t);
282 u_int32_t sshkey_signatures_left(const struct sshkey *);
283 int	 sshkey_forward_state(const struct sshkey *, u_int32_t, sshkey_printfn *);
284 int	 sshkey_private_serialize_maxsign(struct sshkey *key, struct sshbuf *buf,
285     u_int32_t maxsign, sshkey_printfn *pr);
286 
287 void	 sshkey_sig_details_free(struct sshkey_sig_details *);
288 
289 #ifdef SSHKEY_INTERNAL
290 int ssh_rsa_sign(const struct sshkey *key,
291     u_char **sigp, size_t *lenp, const u_char *data, size_t datalen,
292     const char *ident);
293 int ssh_rsa_verify(const struct sshkey *key,
294     const u_char *sig, size_t siglen, const u_char *data, size_t datalen,
295     const char *alg);
296 int ssh_dss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
297     const u_char *data, size_t datalen, u_int compat);
298 int ssh_dss_verify(const struct sshkey *key,
299     const u_char *signature, size_t signaturelen,
300     const u_char *data, size_t datalen, u_int compat);
301 int ssh_ecdsa_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
302     const u_char *data, size_t datalen, u_int compat);
303 int ssh_ecdsa_verify(const struct sshkey *key,
304     const u_char *signature, size_t signaturelen,
305     const u_char *data, size_t datalen, u_int compat);
306 int ssh_ecdsa_sk_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     struct sshkey_sig_details **detailsp);
310 int ssh_ed25519_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
311     const u_char *data, size_t datalen, u_int compat);
312 int ssh_ed25519_verify(const struct sshkey *key,
313     const u_char *signature, size_t signaturelen,
314     const u_char *data, size_t datalen, u_int compat);
315 int ssh_ed25519_sk_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     struct sshkey_sig_details **detailsp);
319 int ssh_xmss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
320     const u_char *data, size_t datalen, u_int compat);
321 int ssh_xmss_verify(const struct sshkey *key,
322     const u_char *signature, size_t signaturelen,
323     const u_char *data, size_t datalen, u_int compat);
324 #endif
325 
326 #if !defined(WITH_OPENSSL)
327 # undef RSA
328 # undef DSA
329 # undef EC_KEY
330 # undef EC_GROUP
331 # undef EC_POINT
332 #elif !defined(OPENSSL_HAS_ECC)
333 # undef EC_KEY
334 # undef EC_GROUP
335 # undef EC_POINT
336 #endif
337 
338 #endif /* SSHKEY_H */
339