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# 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
56struct sshbuf;
57
58/* Key types */
59enum 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 */
81enum 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 */
90enum 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 */
99enum 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? */
110struct 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? */
125struct 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 */
162struct 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
167struct sshkey_impl_funcs {
168	u_int (*size)(const struct sshkey *);	/* optional */
169	int (*alloc)(struct sshkey *);		/* optional */
170	void (*cleanup)(struct sshkey *);	/* optional */
171	int (*equal)(const struct sshkey *, const struct sshkey *);
172	int (*serialize_public)(const struct sshkey *, struct sshbuf *,
173	    enum sshkey_serialize_rep);
174	int (*deserialize_public)(const char *, struct sshbuf *,
175	    struct sshkey *);
176	int (*serialize_private)(const struct sshkey *, struct sshbuf *,
177	    enum sshkey_serialize_rep);
178	int (*deserialize_private)(const char *, struct sshbuf *,
179	    struct sshkey *);
180	int (*generate)(struct sshkey *, int);	/* optional */
181	int (*copy_public)(const struct sshkey *, struct sshkey *);
182	int (*sign)(struct sshkey *, u_char **, size_t *,
183	    const u_char *, size_t, const char *,
184	    const char *, const char *, u_int); /* optional */
185	int (*verify)(const struct sshkey *, const u_char *, size_t,
186	    const u_char *, size_t, const char *, u_int,
187	    struct sshkey_sig_details **);
188};
189
190struct sshkey_impl {
191	const char *name;
192	const char *shortname;
193	const char *sigalg;
194	int type;
195	int nid;
196	int cert;
197	int sigonly;
198	int keybits;
199	const struct sshkey_impl_funcs *funcs;
200};
201
202struct sshkey	*sshkey_new(int);
203void		 sshkey_free(struct sshkey *);
204int		 sshkey_equal_public(const struct sshkey *,
205    const struct sshkey *);
206int		 sshkey_equal(const struct sshkey *, const struct sshkey *);
207char		*sshkey_fingerprint(const struct sshkey *,
208    int, enum sshkey_fp_rep);
209int		 sshkey_fingerprint_raw(const struct sshkey *k,
210    int, u_char **retp, size_t *lenp);
211const char	*sshkey_type(const struct sshkey *);
212const char	*sshkey_cert_type(const struct sshkey *);
213int		 sshkey_format_text(const struct sshkey *, struct sshbuf *);
214int		 sshkey_write(const struct sshkey *, FILE *);
215int		 sshkey_read(struct sshkey *, char **);
216u_int		 sshkey_size(const struct sshkey *);
217
218int		 sshkey_generate(int type, u_int bits, struct sshkey **keyp);
219int		 sshkey_from_private(const struct sshkey *, struct sshkey **);
220
221int		 sshkey_is_shielded(struct sshkey *);
222int		 sshkey_shield_private(struct sshkey *);
223int		 sshkey_unshield_private(struct sshkey *);
224
225int	 sshkey_type_from_name(const char *);
226int	 sshkey_is_cert(const struct sshkey *);
227int	 sshkey_is_sk(const struct sshkey *);
228int	 sshkey_type_is_cert(int);
229int	 sshkey_type_plain(int);
230
231/* Returns non-zero if key name match sigalgs pattern list. (handles RSA) */
232int	 sshkey_match_keyname_to_sigalgs(const char *, const char *);
233
234int	 sshkey_to_certified(struct sshkey *);
235int	 sshkey_drop_cert(struct sshkey *);
236int	 sshkey_cert_copy(const struct sshkey *, struct sshkey *);
237int	 sshkey_cert_check_authority(const struct sshkey *, int, int, int,
238    uint64_t, const char *, const char **);
239int	 sshkey_cert_check_authority_now(const struct sshkey *, int, int, int,
240    const char *, const char **);
241int	 sshkey_cert_check_host(const struct sshkey *, const char *,
242    int , const char *, const char **);
243size_t	 sshkey_format_cert_validity(const struct sshkey_cert *,
244    char *, size_t) __attribute__((__bounded__(__string__, 2, 3)));
245int	 sshkey_check_cert_sigtype(const struct sshkey *, const char *);
246
247int	 sshkey_certify(struct sshkey *, struct sshkey *,
248    const char *, const char *, const char *);
249/* Variant allowing use of a custom signature function (e.g. for ssh-agent) */
250typedef int sshkey_certify_signer(struct sshkey *, u_char **, size_t *,
251    const u_char *, size_t, const char *, const char *, const char *,
252    u_int, void *);
253int	 sshkey_certify_custom(struct sshkey *, struct sshkey *, const char *,
254    const char *, const char *, sshkey_certify_signer *, void *);
255
256int		 sshkey_ecdsa_nid_from_name(const char *);
257int		 sshkey_curve_name_to_nid(const char *);
258const char *	 sshkey_curve_nid_to_name(int);
259u_int		 sshkey_curve_nid_to_bits(int);
260int		 sshkey_ecdsa_bits_to_nid(int);
261int		 sshkey_ecdsa_key_to_nid(EC_KEY *);
262int		 sshkey_ec_nid_to_hash_alg(int nid);
263int		 sshkey_ec_validate_public(const EC_GROUP *, const EC_POINT *);
264int		 sshkey_ec_validate_private(const EC_KEY *);
265const char	*sshkey_ssh_name(const struct sshkey *);
266const char	*sshkey_ssh_name_plain(const struct sshkey *);
267int		 sshkey_names_valid2(const char *, int, int);
268char		*sshkey_alg_list(int, int, int, char);
269
270int	 sshkey_from_blob(const u_char *, size_t, struct sshkey **);
271int	 sshkey_fromb(struct sshbuf *, struct sshkey **);
272int	 sshkey_froms(struct sshbuf *, struct sshkey **);
273int	 sshkey_to_blob(const struct sshkey *, u_char **, size_t *);
274int	 sshkey_to_base64(const struct sshkey *, char **);
275int	 sshkey_putb(const struct sshkey *, struct sshbuf *);
276int	 sshkey_puts(const struct sshkey *, struct sshbuf *);
277int	 sshkey_puts_opts(const struct sshkey *, struct sshbuf *,
278    enum sshkey_serialize_rep);
279int	 sshkey_plain_to_blob(const struct sshkey *, u_char **, size_t *);
280int	 sshkey_putb_plain(const struct sshkey *, struct sshbuf *);
281
282int	 sshkey_sign(struct sshkey *, u_char **, size_t *,
283    const u_char *, size_t, const char *, const char *, const char *, u_int);
284int	 sshkey_verify(const struct sshkey *, const u_char *, size_t,
285    const u_char *, size_t, const char *, u_int, struct sshkey_sig_details **);
286int	 sshkey_check_sigtype(const u_char *, size_t, const char *);
287const char *sshkey_sigalg_by_name(const char *);
288int	 sshkey_get_sigtype(const u_char *, size_t, char **);
289
290/* for debug */
291void	sshkey_dump_ec_point(const EC_GROUP *, const EC_POINT *);
292void	sshkey_dump_ec_key(const EC_KEY *);
293
294/* private key parsing and serialisation */
295int	sshkey_private_serialize(struct sshkey *key, struct sshbuf *buf);
296int	sshkey_private_serialize_opt(struct sshkey *key, struct sshbuf *buf,
297    enum sshkey_serialize_rep);
298int	sshkey_private_deserialize(struct sshbuf *buf,  struct sshkey **keyp);
299
300/* private key file format parsing and serialisation */
301int	sshkey_private_to_fileblob(struct sshkey *key, struct sshbuf *blob,
302    const char *passphrase, const char *comment,
303    int format, const char *openssh_format_cipher, int openssh_format_rounds);
304int	sshkey_parse_private_fileblob(struct sshbuf *buffer,
305    const char *passphrase, struct sshkey **keyp, char **commentp);
306int	sshkey_parse_private_fileblob_type(struct sshbuf *blob, int type,
307    const char *passphrase, struct sshkey **keyp, char **commentp);
308int	sshkey_parse_pubkey_from_private_fileblob_type(struct sshbuf *blob,
309    int type, struct sshkey **pubkeyp);
310
311int sshkey_check_rsa_length(const struct sshkey *, int);
312/* XXX should be internal, but used by ssh-keygen */
313int ssh_rsa_complete_crt_parameters(struct sshkey *, const BIGNUM *);
314
315/* stateful keys (e.g. XMSS) */
316int	 sshkey_set_filename(struct sshkey *, const char *);
317int	 sshkey_enable_maxsign(struct sshkey *, u_int32_t);
318u_int32_t sshkey_signatures_left(const struct sshkey *);
319int	 sshkey_forward_state(const struct sshkey *, u_int32_t, int);
320int	 sshkey_private_serialize_maxsign(struct sshkey *key,
321    struct sshbuf *buf, u_int32_t maxsign, int);
322
323void	 sshkey_sig_details_free(struct sshkey_sig_details *);
324
325#ifdef SSHKEY_INTERNAL
326int	sshkey_sk_fields_equal(const struct sshkey *a, const struct sshkey *b);
327void	sshkey_sk_cleanup(struct sshkey *k);
328int	sshkey_serialize_sk(const struct sshkey *key, struct sshbuf *b);
329int	sshkey_copy_public_sk(const struct sshkey *from, struct sshkey *to);
330int	sshkey_deserialize_sk(struct sshbuf *b, struct sshkey *key);
331int	sshkey_serialize_private_sk(const struct sshkey *key,
332    struct sshbuf *buf);
333int	sshkey_private_deserialize_sk(struct sshbuf *buf, struct sshkey *k);
334#ifdef WITH_OPENSSL
335int	check_rsa_length(const RSA *rsa); /* XXX remove */
336#endif
337#endif
338
339#if !defined(WITH_OPENSSL)
340# undef RSA
341# undef DSA
342# undef EC_KEY
343# undef EC_GROUP
344# undef EC_POINT
345#elif !defined(OPENSSL_HAS_ECC)
346# undef EC_KEY
347# undef EC_GROUP
348# undef EC_POINT
349#endif
350
351#endif /* SSHKEY_H */
352