xref: /openssh-portable/sshkey.h (revision eab2888c)
1 /* $OpenBSD: sshkey.h,v 1.47 2020/10/19 22:49:23 dtucker 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 struct sshbuf;
55 
56 /* Key types */
57 enum sshkey_types {
58 	KEY_RSA,
59 	KEY_DSA,
60 	KEY_ECDSA,
61 	KEY_ED25519,
62 	KEY_RSA_CERT,
63 	KEY_DSA_CERT,
64 	KEY_ECDSA_CERT,
65 	KEY_ED25519_CERT,
66 	KEY_XMSS,
67 	KEY_XMSS_CERT,
68 	KEY_ECDSA_SK,
69 	KEY_ECDSA_SK_CERT,
70 	KEY_ED25519_SK,
71 	KEY_ED25519_SK_CERT,
72 	KEY_UNSPEC
73 };
74 
75 /* Default fingerprint hash */
76 #define SSH_FP_HASH_DEFAULT	SSH_DIGEST_SHA256
77 
78 /* Fingerprint representation formats */
79 enum sshkey_fp_rep {
80 	SSH_FP_DEFAULT = 0,
81 	SSH_FP_HEX,
82 	SSH_FP_BASE64,
83 	SSH_FP_BUBBLEBABBLE,
84 	SSH_FP_RANDOMART
85 };
86 
87 /* Private key serialisation formats, used on the wire */
88 enum sshkey_serialize_rep {
89 	SSHKEY_SERIALIZE_DEFAULT = 0,
90 	SSHKEY_SERIALIZE_STATE = 1,	/* only state is serialized */
91 	SSHKEY_SERIALIZE_FULL = 2,	/* include keys for saving to disk */
92 	SSHKEY_SERIALIZE_SHIELD = 3,	/* everything, for encrypting in ram */
93 	SSHKEY_SERIALIZE_INFO = 254,	/* minimal information */
94 };
95 
96 /* Private key disk formats */
97 enum sshkey_private_format {
98 	SSHKEY_PRIVATE_OPENSSH = 0,
99 	SSHKEY_PRIVATE_PEM = 1,
100 	SSHKEY_PRIVATE_PKCS8 = 2,
101 };
102 
103 /* key is stored in external hardware */
104 #define SSHKEY_FLAG_EXT		0x0001
105 
106 #define SSHKEY_CERT_MAX_PRINCIPALS	256
107 /* XXX opaquify? */
108 struct sshkey_cert {
109 	struct sshbuf	*certblob; /* Kept around for use on wire */
110 	u_int		 type; /* SSH2_CERT_TYPE_USER or SSH2_CERT_TYPE_HOST */
111 	u_int64_t	 serial;
112 	char		*key_id;
113 	u_int		 nprincipals;
114 	char		**principals;
115 	u_int64_t	 valid_after, valid_before;
116 	struct sshbuf	*critical;
117 	struct sshbuf	*extensions;
118 	struct sshkey	*signature_key;
119 	char		*signature_type;
120 };
121 
122 /* XXX opaquify? */
123 struct sshkey {
124 	int	 type;
125 	int	 flags;
126 	/* KEY_RSA */
127 	RSA	*rsa;
128 	/* KEY_DSA */
129 	DSA	*dsa;
130 	/* KEY_ECDSA and KEY_ECDSA_SK */
131 	int	 ecdsa_nid;	/* NID of curve */
132 	EC_KEY	*ecdsa;
133 	/* KEY_ED25519 and KEY_ED25519_SK */
134 	u_char	*ed25519_sk;
135 	u_char	*ed25519_pk;
136 	/* KEY_XMSS */
137 	char	*xmss_name;
138 	char	*xmss_filename;	/* for state file updates */
139 	void	*xmss_state;	/* depends on xmss_name, opaque */
140 	u_char	*xmss_sk;
141 	u_char	*xmss_pk;
142 	/* KEY_ECDSA_SK and KEY_ED25519_SK */
143 	char	*sk_application;
144 	uint8_t	sk_flags;
145 	struct sshbuf *sk_key_handle;
146 	struct sshbuf *sk_reserved;
147 	/* Certificates */
148 	struct sshkey_cert *cert;
149 	/* Private key shielding */
150 	u_char	*shielded_private;
151 	size_t	shielded_len;
152 	u_char	*shield_prekey;
153 	size_t	shield_prekey_len;
154 };
155 
156 #define	ED25519_SK_SZ	crypto_sign_ed25519_SECRETKEYBYTES
157 #define	ED25519_PK_SZ	crypto_sign_ed25519_PUBLICKEYBYTES
158 
159 /* Additional fields contained in signature */
160 struct sshkey_sig_details {
161 	uint32_t sk_counter;	/* U2F signature counter */
162 	uint8_t sk_flags;	/* U2F signature flags; see ssh-sk.h */
163 };
164 
165 struct sshkey	*sshkey_new(int);
166 void		 sshkey_free(struct sshkey *);
167 int		 sshkey_equal_public(const struct sshkey *,
168     const struct sshkey *);
169 int		 sshkey_equal(const struct sshkey *, const struct sshkey *);
170 char		*sshkey_fingerprint(const struct sshkey *,
171     int, enum sshkey_fp_rep);
172 int		 sshkey_fingerprint_raw(const struct sshkey *k,
173     int, u_char **retp, size_t *lenp);
174 const char	*sshkey_type(const struct sshkey *);
175 const char	*sshkey_cert_type(const struct sshkey *);
176 int		 sshkey_format_text(const struct sshkey *, struct sshbuf *);
177 int		 sshkey_write(const struct sshkey *, FILE *);
178 int		 sshkey_read(struct sshkey *, char **);
179 u_int		 sshkey_size(const struct sshkey *);
180 
181 int		 sshkey_generate(int type, u_int bits, struct sshkey **keyp);
182 int		 sshkey_from_private(const struct sshkey *, struct sshkey **);
183 
184 int		 sshkey_is_shielded(struct sshkey *);
185 int		 sshkey_shield_private(struct sshkey *);
186 int		 sshkey_unshield_private(struct sshkey *);
187 
188 int	 sshkey_type_from_name(const char *);
189 int	 sshkey_is_cert(const struct sshkey *);
190 int	 sshkey_is_sk(const struct sshkey *);
191 int	 sshkey_type_is_cert(int);
192 int	 sshkey_type_plain(int);
193 int	 sshkey_to_certified(struct sshkey *);
194 int	 sshkey_drop_cert(struct sshkey *);
195 int	 sshkey_cert_copy(const struct sshkey *, struct sshkey *);
196 int	 sshkey_cert_check_authority(const struct sshkey *, int, int,
197     const char *, const char **);
198 size_t	 sshkey_format_cert_validity(const struct sshkey_cert *,
199     char *, size_t) __attribute__((__bounded__(__string__, 2, 3)));
200 int	 sshkey_check_cert_sigtype(const struct sshkey *, const char *);
201 
202 int	 sshkey_certify(struct sshkey *, struct sshkey *,
203     const char *, const char *, const char *);
204 /* Variant allowing use of a custom signature function (e.g. for ssh-agent) */
205 typedef int sshkey_certify_signer(struct sshkey *, u_char **, size_t *,
206     const u_char *, size_t, const char *, const char *, const char *,
207     u_int, void *);
208 int	 sshkey_certify_custom(struct sshkey *, struct sshkey *, const char *,
209     const char *, const char *, sshkey_certify_signer *, void *);
210 
211 int		 sshkey_ecdsa_nid_from_name(const char *);
212 int		 sshkey_curve_name_to_nid(const char *);
213 const char *	 sshkey_curve_nid_to_name(int);
214 u_int		 sshkey_curve_nid_to_bits(int);
215 int		 sshkey_ecdsa_bits_to_nid(int);
216 int		 sshkey_ecdsa_key_to_nid(EC_KEY *);
217 int		 sshkey_ec_nid_to_hash_alg(int nid);
218 int		 sshkey_ec_validate_public(const EC_GROUP *, const EC_POINT *);
219 int		 sshkey_ec_validate_private(const EC_KEY *);
220 const char	*sshkey_ssh_name(const struct sshkey *);
221 const char	*sshkey_ssh_name_plain(const struct sshkey *);
222 int		 sshkey_names_valid2(const char *, int);
223 char		*sshkey_alg_list(int, int, int, char);
224 
225 int	 sshkey_from_blob(const u_char *, size_t, struct sshkey **);
226 int	 sshkey_fromb(struct sshbuf *, struct sshkey **);
227 int	 sshkey_froms(struct sshbuf *, struct sshkey **);
228 int	 sshkey_to_blob(const struct sshkey *, u_char **, size_t *);
229 int	 sshkey_to_base64(const struct sshkey *, char **);
230 int	 sshkey_putb(const struct sshkey *, struct sshbuf *);
231 int	 sshkey_puts(const struct sshkey *, struct sshbuf *);
232 int	 sshkey_puts_opts(const struct sshkey *, struct sshbuf *,
233     enum sshkey_serialize_rep);
234 int	 sshkey_plain_to_blob(const struct sshkey *, u_char **, size_t *);
235 int	 sshkey_putb_plain(const struct sshkey *, struct sshbuf *);
236 
237 int	 sshkey_sign(struct sshkey *, u_char **, size_t *,
238     const u_char *, size_t, const char *, const char *, const char *, u_int);
239 int	 sshkey_verify(const struct sshkey *, const u_char *, size_t,
240     const u_char *, size_t, const char *, u_int, struct sshkey_sig_details **);
241 int	 sshkey_check_sigtype(const u_char *, size_t, const char *);
242 const char *sshkey_sigalg_by_name(const char *);
243 int	 sshkey_get_sigtype(const u_char *, size_t, char **);
244 
245 /* for debug */
246 void	sshkey_dump_ec_point(const EC_GROUP *, const EC_POINT *);
247 void	sshkey_dump_ec_key(const EC_KEY *);
248 
249 /* private key parsing and serialisation */
250 int	sshkey_private_serialize(struct sshkey *key, struct sshbuf *buf);
251 int	sshkey_private_serialize_opt(struct sshkey *key, struct sshbuf *buf,
252     enum sshkey_serialize_rep);
253 int	sshkey_private_deserialize(struct sshbuf *buf,  struct sshkey **keyp);
254 
255 /* private key file format parsing and serialisation */
256 int	sshkey_private_to_fileblob(struct sshkey *key, struct sshbuf *blob,
257     const char *passphrase, const char *comment,
258     int format, const char *openssh_format_cipher, int openssh_format_rounds);
259 int	sshkey_parse_private_fileblob(struct sshbuf *buffer,
260     const char *passphrase, struct sshkey **keyp, char **commentp);
261 int	sshkey_parse_private_fileblob_type(struct sshbuf *blob, int type,
262     const char *passphrase, struct sshkey **keyp, char **commentp);
263 int	sshkey_parse_pubkey_from_private_fileblob_type(struct sshbuf *blob,
264     int type, struct sshkey **pubkeyp);
265 
266 /* XXX should be internal, but used by ssh-keygen */
267 int ssh_rsa_complete_crt_parameters(struct sshkey *, const BIGNUM *);
268 
269 /* stateful keys (e.g. XMSS) */
270 int	 sshkey_set_filename(struct sshkey *, const char *);
271 int	 sshkey_enable_maxsign(struct sshkey *, u_int32_t);
272 u_int32_t sshkey_signatures_left(const struct sshkey *);
273 int	 sshkey_forward_state(const struct sshkey *, u_int32_t, int);
274 int	 sshkey_private_serialize_maxsign(struct sshkey *key,
275     struct sshbuf *buf, u_int32_t maxsign, int);
276 
277 void	 sshkey_sig_details_free(struct sshkey_sig_details *);
278 
279 #ifdef SSHKEY_INTERNAL
280 int ssh_rsa_sign(const struct sshkey *key,
281     u_char **sigp, size_t *lenp, const u_char *data, size_t datalen,
282     const char *ident);
283 int ssh_rsa_verify(const struct sshkey *key,
284     const u_char *sig, size_t siglen, const u_char *data, size_t datalen,
285     const char *alg);
286 int ssh_dss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
287     const u_char *data, size_t datalen, u_int compat);
288 int ssh_dss_verify(const struct sshkey *key,
289     const u_char *signature, size_t signaturelen,
290     const u_char *data, size_t datalen, u_int compat);
291 int ssh_ecdsa_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
292     const u_char *data, size_t datalen, u_int compat);
293 int ssh_ecdsa_verify(const struct sshkey *key,
294     const u_char *signature, size_t signaturelen,
295     const u_char *data, size_t datalen, u_int compat);
296 int ssh_ecdsa_sk_verify(const struct sshkey *key,
297     const u_char *signature, size_t signaturelen,
298     const u_char *data, size_t datalen, u_int compat,
299     struct sshkey_sig_details **detailsp);
300 int ssh_ed25519_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_ed25519_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_ed25519_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_xmss_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_xmss_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 #endif
315 
316 #if !defined(WITH_OPENSSL)
317 # undef RSA
318 # undef DSA
319 # undef EC_KEY
320 # undef EC_GROUP
321 # undef EC_POINT
322 #elif !defined(OPENSSL_HAS_ECC)
323 # undef EC_KEY
324 # undef EC_GROUP
325 # undef EC_POINT
326 #endif
327 
328 #endif /* SSHKEY_H */
329