1 /* $NetBSD: kex-names.c,v 1.5 2026/04/08 18:58:40 christos Exp $ */ 2 /* $OpenBSD: kex-names.c,v 1.7 2026/02/14 00:18:34 jsg Exp $ */ 3 4 /* 5 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include "includes.h" 29 __RCSID("$NetBSD: kex-names.c,v 1.5 2026/04/08 18:58:40 christos Exp $"); 30 31 #include <stdio.h> 32 #include <stdlib.h> 33 #include <string.h> 34 #include <signal.h> 35 36 #ifdef WITH_OPENSSL 37 #include <openssl/crypto.h> 38 #include <openssl/evp.h> 39 #endif 40 41 #include "kex.h" 42 #include "log.h" 43 #include "match.h" 44 #include "digest.h" 45 #include "misc.h" 46 47 #include "ssherr.h" 48 49 struct kexalg { 50 const char *name; 51 u_int type; 52 int ec_nid; 53 int hash_alg; 54 int pq_alg; 55 }; 56 static const struct kexalg kexalgs[] = { 57 #ifdef WITH_OPENSSL 58 { KEX_DH1, KEX_DH_GRP1_SHA1, 0, SSH_DIGEST_SHA1, KEX_NOT_PQ }, 59 { KEX_DH14_SHA1, KEX_DH_GRP14_SHA1, 0, SSH_DIGEST_SHA1, KEX_NOT_PQ }, 60 { KEX_DH14_SHA256, KEX_DH_GRP14_SHA256, 0, SSH_DIGEST_SHA256, KEX_NOT_PQ }, 61 { KEX_DH16_SHA512, KEX_DH_GRP16_SHA512, 0, SSH_DIGEST_SHA512, KEX_NOT_PQ }, 62 { KEX_DH18_SHA512, KEX_DH_GRP18_SHA512, 0, SSH_DIGEST_SHA512, KEX_NOT_PQ }, 63 { KEX_DHGEX_SHA1, KEX_DH_GEX_SHA1, 0, SSH_DIGEST_SHA1, KEX_NOT_PQ }, 64 { KEX_DHGEX_SHA256, KEX_DH_GEX_SHA256, 0, SSH_DIGEST_SHA256, KEX_NOT_PQ }, 65 { KEX_ECDH_SHA2_NISTP256, KEX_ECDH_SHA2, 66 NID_X9_62_prime256v1, SSH_DIGEST_SHA256, KEX_NOT_PQ }, 67 { KEX_ECDH_SHA2_NISTP384, KEX_ECDH_SHA2, NID_secp384r1, 68 SSH_DIGEST_SHA384, KEX_NOT_PQ }, 69 { KEX_ECDH_SHA2_NISTP521, KEX_ECDH_SHA2, NID_secp521r1, 70 SSH_DIGEST_SHA512, KEX_NOT_PQ }, 71 #endif 72 { KEX_CURVE25519_SHA256, KEX_C25519_SHA256, 0, 73 SSH_DIGEST_SHA256, KEX_NOT_PQ }, 74 { KEX_CURVE25519_SHA256_OLD, KEX_C25519_SHA256, 0, 75 SSH_DIGEST_SHA256, KEX_NOT_PQ }, 76 { KEX_SNTRUP761X25519_SHA512, KEX_KEM_SNTRUP761X25519_SHA512, 0, 77 SSH_DIGEST_SHA512, KEX_IS_PQ }, 78 { KEX_SNTRUP761X25519_SHA512_OLD, KEX_KEM_SNTRUP761X25519_SHA512, 0, 79 SSH_DIGEST_SHA512, KEX_IS_PQ }, 80 { KEX_MLKEM768X25519_SHA256, KEX_KEM_MLKEM768X25519_SHA256, 0, 81 SSH_DIGEST_SHA256, KEX_IS_PQ }, 82 { NULL, 0, -1, -1, 0}, 83 }; 84 85 char * 86 kex_alg_list(char sep) 87 { 88 char *ret = NULL; 89 const struct kexalg *k; 90 char sep_str[2] = {sep, '\0'}; 91 92 for (k = kexalgs; k->name != NULL; k++) 93 xextendf(&ret, sep_str, "%s", k->name); 94 95 return ret; 96 } 97 98 static const struct kexalg * 99 kex_alg_by_name(const char *name) 100 { 101 const struct kexalg *k; 102 103 for (k = kexalgs; k->name != NULL; k++) { 104 if (strcmp(k->name, name) == 0) 105 return k; 106 } 107 return NULL; 108 } 109 110 int 111 kex_name_valid(const char *name) 112 { 113 return kex_alg_by_name(name) != NULL; 114 } 115 116 int 117 kex_is_pq_from_name(const char *name) 118 { 119 const struct kexalg *k; 120 121 if ((k = kex_alg_by_name(name)) == NULL) 122 return 0; 123 return k->pq_alg == KEX_IS_PQ; 124 } 125 126 u_int 127 kex_type_from_name(const char *name) 128 { 129 const struct kexalg *k; 130 131 if ((k = kex_alg_by_name(name)) == NULL) 132 return 0; 133 return k->type; 134 } 135 136 int 137 kex_hash_from_name(const char *name) 138 { 139 const struct kexalg *k; 140 141 if ((k = kex_alg_by_name(name)) == NULL) 142 return -1; 143 return k->hash_alg; 144 } 145 146 int 147 kex_nid_from_name(const char *name) 148 { 149 const struct kexalg *k; 150 151 if ((k = kex_alg_by_name(name)) == NULL) 152 return -1; 153 return k->ec_nid; 154 } 155 156 /* Validate KEX method name list */ 157 int 158 kex_names_valid(const char *names) 159 { 160 char *s, *cp, *p; 161 162 if (names == NULL || strcmp(names, "") == 0) 163 return 0; 164 if ((s = cp = strdup(names)) == NULL) 165 return 0; 166 for ((p = strsep(&cp, ",")); p && *p != '\0'; 167 (p = strsep(&cp, ","))) { 168 if (kex_alg_by_name(p) == NULL) { 169 error("Unsupported KEX algorithm \"%.100s\"", p); 170 free(s); 171 return 0; 172 } 173 } 174 debug3("kex names ok: [%s]", names); 175 free(s); 176 return 1; 177 } 178 179 /* returns non-zero if proposal contains any algorithm from algs */ 180 int 181 kex_has_any_alg(const char *proposal, const char *algs) 182 { 183 char *cp; 184 185 if ((cp = match_list(proposal, algs, NULL)) == NULL) 186 return 0; 187 free(cp); 188 return 1; 189 } 190 191 /* 192 * Concatenate algorithm names, avoiding duplicates in the process. 193 * Caller must free returned string. 194 */ 195 char * 196 kex_names_cat(const char *a, const char *b) 197 { 198 char *ret = NULL, *tmp = NULL, *cp, *p; 199 size_t len; 200 201 if (a == NULL || *a == '\0') 202 return strdup(b); 203 if (b == NULL || *b == '\0') 204 return strdup(a); 205 if (strlen(b) > 1024*1024) 206 return NULL; 207 len = strlen(a) + strlen(b) + 2; 208 if ((tmp = cp = strdup(b)) == NULL || 209 (ret = calloc(1, len)) == NULL) { 210 free(tmp); 211 return NULL; 212 } 213 strlcpy(ret, a, len); 214 for ((p = strsep(&cp, ",")); p && *p != '\0'; (p = strsep(&cp, ","))) { 215 if (kex_has_any_alg(ret, p)) 216 continue; /* Algorithm already present */ 217 if (strlcat(ret, ",", len) >= len || 218 strlcat(ret, p, len) >= len) { 219 free(tmp); 220 free(ret); 221 return NULL; /* Shouldn't happen */ 222 } 223 } 224 free(tmp); 225 return ret; 226 } 227 228 /* 229 * Assemble a list of algorithms from a default list and a string from a 230 * configuration file. The user-provided string may begin with '+' to 231 * indicate that it should be appended to the default, '-' that the 232 * specified names should be removed, or '^' that they should be placed 233 * at the head. 234 */ 235 int 236 kex_assemble_names(char **listp, const char *def, const char *all) 237 { 238 char *cp, *tmp, *patterns; 239 char *list = NULL, *ret = NULL, *matching = NULL, *opatterns = NULL; 240 int r = SSH_ERR_INTERNAL_ERROR; 241 242 if (listp == NULL || def == NULL || all == NULL) 243 return SSH_ERR_INVALID_ARGUMENT; 244 245 if (*listp == NULL || **listp == '\0') { 246 if ((*listp = strdup(def)) == NULL) 247 return SSH_ERR_ALLOC_FAIL; 248 return 0; 249 } 250 251 list = *listp; 252 *listp = NULL; 253 if (*list == '+') { 254 /* Append names to default list */ 255 if ((tmp = kex_names_cat(def, list + 1)) == NULL) { 256 r = SSH_ERR_ALLOC_FAIL; 257 goto fail; 258 } 259 free(list); 260 list = tmp; 261 } else if (*list == '-') { 262 /* Remove names from default list */ 263 if ((*listp = match_filter_denylist(def, list + 1)) == NULL) { 264 r = SSH_ERR_ALLOC_FAIL; 265 goto fail; 266 } 267 free(list); 268 /* filtering has already been done */ 269 return 0; 270 } else if (*list == '^') { 271 /* Place names at head of default list */ 272 if ((tmp = kex_names_cat(list + 1, def)) == NULL) { 273 r = SSH_ERR_ALLOC_FAIL; 274 goto fail; 275 } 276 free(list); 277 list = tmp; 278 } else { 279 /* Explicit list, overrides default - just use "list" as is */ 280 } 281 282 /* 283 * The supplied names may be a pattern-list. For the -list case, 284 * the patterns are applied above. For the +list and explicit list 285 * cases we need to do it now. 286 */ 287 ret = NULL; 288 if ((patterns = opatterns = strdup(list)) == NULL) { 289 r = SSH_ERR_ALLOC_FAIL; 290 goto fail; 291 } 292 /* Apply positive (i.e. non-negated) patterns from the list */ 293 while ((cp = strsep(&patterns, ",")) != NULL) { 294 if (*cp == '!') { 295 /* negated matches are not supported here */ 296 r = SSH_ERR_INVALID_ARGUMENT; 297 goto fail; 298 } 299 free(matching); 300 if ((matching = match_filter_allowlist(all, cp)) == NULL) { 301 r = SSH_ERR_ALLOC_FAIL; 302 goto fail; 303 } 304 if ((tmp = kex_names_cat(ret, matching)) == NULL) { 305 r = SSH_ERR_ALLOC_FAIL; 306 goto fail; 307 } 308 free(ret); 309 ret = tmp; 310 } 311 if (ret == NULL || *ret == '\0') { 312 /* An empty name-list is an error */ 313 /* XXX better error code? */ 314 r = SSH_ERR_INVALID_ARGUMENT; 315 goto fail; 316 } 317 318 /* success */ 319 *listp = ret; 320 ret = NULL; 321 r = 0; 322 323 fail: 324 free(matching); 325 free(opatterns); 326 free(list); 327 free(ret); 328 return r; 329 } 330
Indexes created Wed Jun 24 00:24:50 UTC 2026