sshkey.h

   1 /* $OpenBSD: sshkey.h,v 1.65 2024/09/04 05:33:34 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 #include <openssl/evp.h>
  35 # ifdef OPENSSL_HAS_ECC
  36 #  include <openssl/ec.h>
  37 #  include <openssl/ecdsa.h>
  38 # else /* OPENSSL_HAS_ECC */
  39 #  define EC_KEY        void
  40 #  define EC_GROUP      void
  41 #  define EC_POINT      void
  42 # endif /* OPENSSL_HAS_ECC */
  43 #define SSH_OPENSSL_VERSION OpenSSL_version(OPENSSL_VERSION)
  44 #else /* WITH_OPENSSL */
  45 # define BIGNUM         void
  46 # define RSA            void
  47 # define DSA            void
  48 # define EC_KEY         void
  49 # define EC_GROUP       void
  50 # define EC_POINT       void
  51 # define EVP_PKEY       void
  52 #define SSH_OPENSSL_VERSION "without OpenSSL"
  53 #endif /* WITH_OPENSSL */
  54
  55 #define SSH_RSA_MINIMUM_MODULUS_SIZE    1024
  56 #define SSH_KEY_MAX_SIGN_DATA_SIZE      (1 << 20)
  57
  58 struct sshbuf;
  59
  60 /* Key types */
  61 enum sshkey_types {
  62         KEY_RSA,
  63         KEY_DSA,
  64         KEY_ECDSA,
  65         KEY_ED25519,
  66         KEY_RSA_CERT,
  67         KEY_DSA_CERT,
  68         KEY_ECDSA_CERT,
  69         KEY_ED25519_CERT,
  70         KEY_XMSS,
  71         KEY_XMSS_CERT,
  72         KEY_ECDSA_SK,
  73         KEY_ECDSA_SK_CERT,
  74         KEY_ED25519_SK,
  75         KEY_ED25519_SK_CERT,
  76         KEY_UNSPEC
  77 };
  78
  79 /* Default fingerprint hash */
  80 #define SSH_FP_HASH_DEFAULT     SSH_DIGEST_SHA256
  81
  82 /* Fingerprint representation formats */
  83 enum sshkey_fp_rep {
  84         SSH_FP_DEFAULT = 0,
  85         SSH_FP_HEX,
  86         SSH_FP_BASE64,
  87         SSH_FP_BUBBLEBABBLE,
  88         SSH_FP_RANDOMART
  89 };
  90
  91 /* Private key serialisation formats, used on the wire */
  92 enum sshkey_serialize_rep {
  93         SSHKEY_SERIALIZE_DEFAULT = 0,
  94         SSHKEY_SERIALIZE_STATE = 1,     /* only state is serialized */
  95         SSHKEY_SERIALIZE_FULL = 2,      /* include keys for saving to disk */
  96         SSHKEY_SERIALIZE_SHIELD = 3,    /* everything, for encrypting in ram */
  97         SSHKEY_SERIALIZE_INFO = 254,    /* minimal information */
  98 };
  99
 100 /* Private key disk formats */
 101 enum sshkey_private_format {
 102         SSHKEY_PRIVATE_OPENSSH = 0,
 103         SSHKEY_PRIVATE_PEM = 1,
 104         SSHKEY_PRIVATE_PKCS8 = 2,
 105 };
 106
 107 /* key is stored in external hardware */
 108 #define SSHKEY_FLAG_EXT         0x0001
 109
 110 #define SSHKEY_CERT_MAX_PRINCIPALS      256
 111 /* XXX opaquify? */
 112 struct sshkey_cert {
 113         struct sshbuf   *certblob; /* Kept around for use on wire */
 114         u_int            type; /* SSH2_CERT_TYPE_USER or SSH2_CERT_TYPE_HOST */
 115         u_int64_t        serial;
 116         char            *key_id;
 117         u_int            nprincipals;
 118         char            **principals;
 119         u_int64_t        valid_after, valid_before;
 120         struct sshbuf   *critical;
 121         struct sshbuf   *extensions;
 122         struct sshkey   *signature_key;
 123         char            *signature_type;
 124 };
 125
 126 /* XXX opaquify? */
 127 struct sshkey {
 128         int      type;
 129         int      flags;
 130         /* KEY_DSA */
 131         DSA     *dsa;
 132         /* KEY_ECDSA and KEY_ECDSA_SK */
 133         int      ecdsa_nid;     /* NID of curve */
 134         /* libcrypto-backed keys */
 135         EVP_PKEY *pkey;
 136         /* KEY_ED25519 and KEY_ED25519_SK */
 137         u_char  *ed25519_sk;
 138         u_char  *ed25519_pk;
 139         /* KEY_XMSS */
 140         char    *xmss_name;
 141         char    *xmss_filename; /* for state file updates */
 142         void    *xmss_state;    /* depends on xmss_name, opaque */
 143         u_char  *xmss_sk;
 144         u_char  *xmss_pk;
 145         /* KEY_ECDSA_SK and KEY_ED25519_SK */
 146         char    *sk_application;
 147         uint8_t sk_flags;
 148         struct sshbuf *sk_key_handle;
 149         struct sshbuf *sk_reserved;
 150         /* Certificates */
 151         struct sshkey_cert *cert;
 152         /* Private key shielding */
 153         u_char  *shielded_private;
 154         size_t  shielded_len;
 155         u_char  *shield_prekey;
 156         size_t  shield_prekey_len;
 157 };
 158
 159 #define ED25519_SK_SZ   crypto_sign_ed25519_SECRETKEYBYTES
 160 #define ED25519_PK_SZ   crypto_sign_ed25519_PUBLICKEYBYTES
 161
 162 /* Additional fields contained in signature */
 163 struct sshkey_sig_details {
 164         uint32_t sk_counter;    /* U2F signature counter */
 165         uint8_t sk_flags;       /* U2F signature flags; see ssh-sk.h */
 166 };
 167
 168 struct sshkey_impl_funcs {
 169         u_int (*size)(const struct sshkey *);   /* optional */
 170         int (*alloc)(struct sshkey *);          /* optional */
 171         void (*cleanup)(struct sshkey *);       /* optional */
 172         int (*equal)(const struct sshkey *, const struct sshkey *);
 173         int (*serialize_public)(const struct sshkey *, struct sshbuf *,
 174             enum sshkey_serialize_rep);
 175         int (*deserialize_public)(const char *, struct sshbuf *,
 176             struct sshkey *);
 177         int (*serialize_private)(const struct sshkey *, struct sshbuf *,
 178             enum sshkey_serialize_rep);
 179         int (*deserialize_private)(const char *, struct sshbuf *,
 180             struct sshkey *);
 181         int (*generate)(struct sshkey *, int);  /* optional */
 182         int (*copy_public)(const struct sshkey *, struct sshkey *);
 183         int (*sign)(struct sshkey *, u_char **, size_t *,
 184             const u_char *, size_t, const char *,
 185             const char *, const char *, u_int); /* optional */
 186         int (*verify)(const struct sshkey *, const u_char *, size_t,
 187             const u_char *, size_t, const char *, u_int,
 188             struct sshkey_sig_details **);
 189 };
 190
 191 struct sshkey_impl {
 192         const char *name;
 193         const char *shortname;
 194         const char *sigalg;
 195         int type;
 196         int nid;
 197         int cert;
 198         int sigonly;
 199         int keybits;
 200         const struct sshkey_impl_funcs *funcs;
 201 };
 202
 203 struct sshkey   *sshkey_new(int);
 204 void             sshkey_free(struct sshkey *);
 205 int              sshkey_equal_public(const struct sshkey *,
 206     const struct sshkey *);
 207 int              sshkey_equal(const struct sshkey *, const struct sshkey *);
 208 char            *sshkey_fingerprint(const struct sshkey *,
 209     int, enum sshkey_fp_rep);
 210 int              sshkey_fingerprint_raw(const struct sshkey *k,
 211     int, u_char **retp, size_t *lenp);
 212 const char      *sshkey_type(const struct sshkey *);
 213 const char      *sshkey_cert_type(const struct sshkey *);
 214 int              sshkey_format_text(const struct sshkey *, struct sshbuf *);
 215 int              sshkey_write(const struct sshkey *, FILE *);
 216 int              sshkey_read(struct sshkey *, char **);
 217 u_int            sshkey_size(const struct sshkey *);
 218
 219 int              sshkey_generate(int type, u_int bits, struct sshkey **keyp);
 220 int              sshkey_from_private(const struct sshkey *, struct sshkey **);
 221
 222 int              sshkey_is_shielded(struct sshkey *);
 223 int              sshkey_shield_private(struct sshkey *);
 224 int              sshkey_unshield_private(struct sshkey *);
 225
 226 int      sshkey_type_from_name(const char *);
 227 int      sshkey_type_from_shortname(const char *);
 228 int      sshkey_is_cert(const struct sshkey *);
 229 int      sshkey_is_sk(const struct sshkey *);
 230 int      sshkey_type_is_cert(int);
 231 int      sshkey_type_plain(int);
 232
 233 /* Returns non-zero if key name match sigalgs pattern list. (handles RSA) */
 234 int      sshkey_match_keyname_to_sigalgs(const char *, const char *);
 235
 236 int      sshkey_to_certified(struct sshkey *);
 237 int      sshkey_drop_cert(struct sshkey *);
 238 int      sshkey_cert_copy(const struct sshkey *, struct sshkey *);
 239 int      sshkey_cert_check_authority(const struct sshkey *, int, int, int,
 240     uint64_t, const char *, const char **);
 241 int      sshkey_cert_check_authority_now(const struct sshkey *, int, int, int,
 242     const char *, const char **);
 243 int      sshkey_cert_check_host(const struct sshkey *, const char *,
 244     int , const char *, const char **);
 245 size_t   sshkey_format_cert_validity(const struct sshkey_cert *,
 246     char *, size_t) __attribute__((__bounded__(__string__, 2, 3)));
 247 int      sshkey_check_cert_sigtype(const struct sshkey *, const char *);
 248
 249 int      sshkey_certify(struct sshkey *, struct sshkey *,
 250     const char *, const char *, const char *);
 251 /* Variant allowing use of a custom signature function (e.g. for ssh-agent) */
 252 typedef int sshkey_certify_signer(struct sshkey *, u_char **, size_t *,
 253     const u_char *, size_t, const char *, const char *, const char *,
 254     u_int, void *);
 255 int      sshkey_certify_custom(struct sshkey *, struct sshkey *, const char *,
 256     const char *, const char *, sshkey_certify_signer *, void *);
 257
 258 int              sshkey_ecdsa_nid_from_name(const char *);
 259 int              sshkey_curve_name_to_nid(const char *);
 260 const char *     sshkey_curve_nid_to_name(int);
 261 u_int            sshkey_curve_nid_to_bits(int);
 262 int              sshkey_ecdsa_bits_to_nid(int);
 263 int              sshkey_ecdsa_key_to_nid(const EC_KEY *);
 264 int              sshkey_ecdsa_pkey_to_nid(EVP_PKEY *);
 265 int              sshkey_ec_nid_to_hash_alg(int nid);
 266 int              sshkey_ec_validate_public(const EC_GROUP *, const EC_POINT *);
 267 int              sshkey_ec_validate_private(const EC_KEY *);
 268 const char      *sshkey_ssh_name(const struct sshkey *);
 269 const char      *sshkey_ssh_name_plain(const struct sshkey *);
 270 int              sshkey_names_valid2(const char *, int, int);
 271 char            *sshkey_alg_list(int, int, int, char);
 272
 273 int      sshkey_from_blob(const u_char *, size_t, struct sshkey **);
 274 int      sshkey_fromb(struct sshbuf *, struct sshkey **);
 275 int      sshkey_froms(struct sshbuf *, struct sshkey **);
 276 int      sshkey_to_blob(const struct sshkey *, u_char **, size_t *);
 277 int      sshkey_to_base64(const struct sshkey *, char **);
 278 int      sshkey_putb(const struct sshkey *, struct sshbuf *);
 279 int      sshkey_puts(const struct sshkey *, struct sshbuf *);
 280 int      sshkey_puts_opts(const struct sshkey *, struct sshbuf *,
 281     enum sshkey_serialize_rep);
 282 int      sshkey_plain_to_blob(const struct sshkey *, u_char **, size_t *);
 283 int      sshkey_putb_plain(const struct sshkey *, struct sshbuf *);
 284
 285 int      sshkey_sign(struct sshkey *, u_char **, size_t *,
 286     const u_char *, size_t, const char *, const char *, const char *, u_int);
 287 int      sshkey_verify(const struct sshkey *, const u_char *, size_t,
 288     const u_char *, size_t, const char *, u_int, struct sshkey_sig_details **);
 289 int      sshkey_check_sigtype(const u_char *, size_t, const char *);
 290 const char *sshkey_sigalg_by_name(const char *);
 291 int      sshkey_get_sigtype(const u_char *, size_t, char **);
 292
 293 /* Signing and verification backend for libcrypto-backed keys */
 294 int     sshkey_pkey_digest_sign(EVP_PKEY*, int, u_char **,
 295     size_t *, const u_char *, size_t);
 296 int     sshkey_pkey_digest_verify(EVP_PKEY *, int, const u_char *,
 297     size_t, u_char *, size_t);
 298
 299 /* for debug */
 300 void    sshkey_dump_ec_point(const EC_GROUP *, const EC_POINT *);
 301 void    sshkey_dump_ec_key(const EC_KEY *);
 302
 303 /* private key parsing and serialisation */
 304 int     sshkey_private_serialize(struct sshkey *key, struct sshbuf *buf);
 305 int     sshkey_private_serialize_opt(struct sshkey *key, struct sshbuf *buf,
 306     enum sshkey_serialize_rep);
 307 int     sshkey_private_deserialize(struct sshbuf *buf,  struct sshkey **keyp);
 308
 309 /* private key file format parsing and serialisation */
 310 int     sshkey_private_to_fileblob(struct sshkey *key, struct sshbuf *blob,
 311     const char *passphrase, const char *comment,
 312     int format, const char *openssh_format_cipher, int openssh_format_rounds);
 313 int     sshkey_parse_private_fileblob(struct sshbuf *buffer,
 314     const char *passphrase, struct sshkey **keyp, char **commentp);
 315 int     sshkey_parse_private_fileblob_type(struct sshbuf *blob, int type,
 316     const char *passphrase, struct sshkey **keyp, char **commentp);
 317 int     sshkey_parse_pubkey_from_private_fileblob_type(struct sshbuf *blob,
 318     int type, struct sshkey **pubkeyp);
 319
 320 int sshkey_check_rsa_length(const struct sshkey *, int);
 321 /* XXX should be internal, but used by ssh-keygen */
 322 int ssh_rsa_complete_crt_parameters(const BIGNUM *, const BIGNUM *,
 323     const BIGNUM *, const BIGNUM *, BIGNUM **, BIGNUM **);
 324
 325 /* stateful keys (e.g. XMSS) */
 326 int      sshkey_set_filename(struct sshkey *, const char *);
 327 int      sshkey_enable_maxsign(struct sshkey *, u_int32_t);
 328 u_int32_t sshkey_signatures_left(const struct sshkey *);
 329 int      sshkey_private_serialize_maxsign(struct sshkey *key,
 330     struct sshbuf *buf, u_int32_t maxsign, int);
 331
 332 void     sshkey_sig_details_free(struct sshkey_sig_details *);
 333
 334 #ifdef WITH_OPENSSL
 335 int     sshkey_ecdsa_fixup_group(EVP_PKEY *k); /* ssh-ecdsa.c */
 336 #endif
 337
 338 #ifdef SSHKEY_INTERNAL
 339 int     sshkey_sk_fields_equal(const struct sshkey *a, const struct sshkey *b);
 340 void    sshkey_sk_cleanup(struct sshkey *k);
 341 int     sshkey_serialize_sk(const struct sshkey *key, struct sshbuf *b);
 342 int     sshkey_copy_public_sk(const struct sshkey *from, struct sshkey *to);
 343 int     sshkey_deserialize_sk(struct sshbuf *b, struct sshkey *key);
 344 int     sshkey_serialize_private_sk(const struct sshkey *key,
 345     struct sshbuf *buf);
 346 int     sshkey_private_deserialize_sk(struct sshbuf *buf, struct sshkey *k);
 347 #ifdef WITH_OPENSSL
 348 int     check_rsa_length(const RSA *rsa); /* XXX remove */
 349 #endif
 350 #endif
 351
 352 #if !defined(WITH_OPENSSL)
 353 # undef RSA
 354 # undef DSA
 355 # undef EC_KEY
 356 # undef EC_GROUP
 357 # undef EC_POINT
 358 # undef EVP_PKEY
 359 #elif !defined(OPENSSL_HAS_ECC)
 360 # undef EC_KEY
 361 # undef EC_GROUP
 362 # undef EC_POINT
 363 #endif
 364
 365 #endif /* SSHKEY_H */