--- /dev/null
+/*
+ * Copyright (c) 2012,2023 Damien Miller <djm@mindrot.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <sys/queue.h>
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "log.h"
+#include "misc.h"
+#include "servconf.h"
+#include "xmalloc.h"
+#include "hostfile.h"
+#include "auth.h"
+
+extern ServerOptions options;
+
+/*
+ * Configuration of enabled authentication methods. Separate to the rest of
+ * auth2-*.c because we want to query it during server configuration validity
+ * checking in the sshd listener process without pulling all the auth code in
+ * too.
+ */
+
+/* "none" is allowed only one time and it cleared by userauth_none() later */
+int none_enabled = 1;
+struct authmethod_cfg methodcfg_none = {
+ "none",
+ NULL,
+ &none_enabled
+};
+struct authmethod_cfg methodcfg_pubkey = {
+ "publickey",
+ "publickey-hostbound-v00@openssh.com",
+ &options.pubkey_authentication
+};
+#ifdef GSSAPI
+struct authmethod_cfg methodcfg_gssapi = {
+ "gssapi-with-mic",
+ NULL,
+ &options.gss_authentication
+};
+#endif
+struct authmethod_cfg methodcfg_passwd = {
+ "password",
+ NULL,
+ &options.password_authentication
+};
+struct authmethod_cfg methodcfg_kbdint = {
+ "keyboard-interactive",
+ NULL,
+ &options.kbd_interactive_authentication
+};
+struct authmethod_cfg methodcfg_hostbased = {
+ "hostbased",
+ NULL,
+ &options.hostbased_authentication
+};
+
+static struct authmethod_cfg *authmethod_cfgs[] = {
+ &methodcfg_none,
+ &methodcfg_pubkey,
+#ifdef GSSAPI
+ &methodcfg_gssapi,
+#endif
+ &methodcfg_passwd,
+ &methodcfg_kbdint,
+ &methodcfg_hostbased,
+ NULL
+};
+
+/*
+ * Check a comma-separated list of methods for validity. Is need_enable is
+ * non-zero, then also require that the methods are enabled.
+ * Returns 0 on success or -1 if the methods list is invalid.
+ */
+int
+auth2_methods_valid(const char *_methods, int need_enable)
+{
+ char *methods, *omethods, *method, *p;
+ u_int i, found;
+ int ret = -1;
+ const struct authmethod_cfg *cfg;
+
+ if (*_methods == '\0') {
+ error("empty authentication method list");
+ return -1;
+ }
+ omethods = methods = xstrdup(_methods);
+ while ((method = strsep(&methods, ",")) != NULL) {
+ for (found = i = 0; !found && authmethod_cfgs[i] != NULL; i++) {
+ cfg = authmethod_cfgs[i];
+ if ((p = strchr(method, ':')) != NULL)
+ *p = '\0';
+ if (strcmp(method, cfg->name) != 0)
+ continue;
+ if (need_enable) {
+ if (cfg->enabled == NULL ||
+ *(cfg->enabled) == 0) {
+ error("Disabled method \"%s\" in "
+ "AuthenticationMethods list \"%s\"",
+ method, _methods);
+ goto out;
+ }
+ }
+ found = 1;
+ break;
+ }
+ if (!found) {
+ error("Unknown authentication method \"%s\" in list",
+ method);
+ goto out;
+ }
+ }
+ ret = 0;
+ out:
+ free(omethods);
+ return ret;
+}
--- /dev/null
+/* $OpenBSD: kex-names.c,v 1.1 2024/05/17 00:32:32 djm Exp $ */
+/*
+ * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <signal.h>
+
+#ifdef WITH_OPENSSL
+#include <openssl/crypto.h>
+#include <openssl/evp.h>
+#endif
+
+#include "kex.h"
+#include "log.h"
+#include "match.h"
+#include "digest.h"
+#include "misc.h"
+
+#include "ssherr.h"
+#include "xmalloc.h"
+
+struct kexalg {
+ char *name;
+ u_int type;
+ int ec_nid;
+ int hash_alg;
+};
+static const struct kexalg kexalgs[] = {
+#ifdef WITH_OPENSSL
+ { KEX_DH1, KEX_DH_GRP1_SHA1, 0, SSH_DIGEST_SHA1 },
+ { KEX_DH14_SHA1, KEX_DH_GRP14_SHA1, 0, SSH_DIGEST_SHA1 },
+ { KEX_DH14_SHA256, KEX_DH_GRP14_SHA256, 0, SSH_DIGEST_SHA256 },
+ { KEX_DH16_SHA512, KEX_DH_GRP16_SHA512, 0, SSH_DIGEST_SHA512 },
+ { KEX_DH18_SHA512, KEX_DH_GRP18_SHA512, 0, SSH_DIGEST_SHA512 },
+ { KEX_DHGEX_SHA1, KEX_DH_GEX_SHA1, 0, SSH_DIGEST_SHA1 },
+ { KEX_DHGEX_SHA256, KEX_DH_GEX_SHA256, 0, SSH_DIGEST_SHA256 },
+ { KEX_ECDH_SHA2_NISTP256, KEX_ECDH_SHA2,
+ NID_X9_62_prime256v1, SSH_DIGEST_SHA256 },
+ { KEX_ECDH_SHA2_NISTP384, KEX_ECDH_SHA2, NID_secp384r1,
+ SSH_DIGEST_SHA384 },
+ { KEX_ECDH_SHA2_NISTP521, KEX_ECDH_SHA2, NID_secp521r1,
+ SSH_DIGEST_SHA512 },
+#endif
+ { KEX_CURVE25519_SHA256, KEX_C25519_SHA256, 0, SSH_DIGEST_SHA256 },
+ { KEX_CURVE25519_SHA256_OLD, KEX_C25519_SHA256, 0, SSH_DIGEST_SHA256 },
+ { KEX_SNTRUP761X25519_SHA512, KEX_KEM_SNTRUP761X25519_SHA512, 0,
+ SSH_DIGEST_SHA512 },
+ { NULL, 0, -1, -1},
+};
+
+char *
+kex_alg_list(char sep)
+{
+ char *ret = NULL, *tmp;
+ size_t nlen, rlen = 0;
+ const struct kexalg *k;
+
+ for (k = kexalgs; k->name != NULL; k++) {
+ if (ret != NULL)
+ ret[rlen++] = sep;
+ nlen = strlen(k->name);
+ if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) {
+ free(ret);
+ return NULL;
+ }
+ ret = tmp;
+ memcpy(ret + rlen, k->name, nlen + 1);
+ rlen += nlen;
+ }
+ return ret;
+}
+
+static const struct kexalg *
+kex_alg_by_name(const char *name)
+{
+ const struct kexalg *k;
+
+ for (k = kexalgs; k->name != NULL; k++) {
+ if (strcmp(k->name, name) == 0)
+ return k;
+ }
+ return NULL;
+}
+
+int
+kex_name_valid(const char *name)
+{
+ return kex_alg_by_name(name) != NULL;
+}
+
+u_int
+kex_type_from_name(const char *name)
+{
+ const struct kexalg *k;
+
+ if ((k = kex_alg_by_name(name)) == NULL)
+ return 0;
+ return k->type;
+}
+
+int
+kex_hash_from_name(const char *name)
+{
+ const struct kexalg *k;
+
+ if ((k = kex_alg_by_name(name)) == NULL)
+ return -1;
+ return k->hash_alg;
+}
+
+int
+kex_nid_from_name(const char *name)
+{
+ const struct kexalg *k;
+
+ if ((k = kex_alg_by_name(name)) == NULL)
+ return -1;
+ return k->ec_nid;
+}
+
+/* Validate KEX method name list */
+int
+kex_names_valid(const char *names)
+{
+ char *s, *cp, *p;
+
+ if (names == NULL || strcmp(names, "") == 0)
+ return 0;
+ if ((s = cp = strdup(names)) == NULL)
+ return 0;
+ for ((p = strsep(&cp, ",")); p && *p != '\0';
+ (p = strsep(&cp, ","))) {
+ if (kex_alg_by_name(p) == NULL) {
+ error("Unsupported KEX algorithm \"%.100s\"", p);
+ free(s);
+ return 0;
+ }
+ }
+ debug3("kex names ok: [%s]", names);
+ free(s);
+ return 1;
+}
+
+/* returns non-zero if proposal contains any algorithm from algs */
+int
+kex_has_any_alg(const char *proposal, const char *algs)
+{
+ char *cp;
+
+ if ((cp = match_list(proposal, algs, NULL)) == NULL)
+ return 0;
+ free(cp);
+ return 1;
+}
+
+/*
+ * Concatenate algorithm names, avoiding duplicates in the process.
+ * Caller must free returned string.
+ */
+char *
+kex_names_cat(const char *a, const char *b)
+{
+ char *ret = NULL, *tmp = NULL, *cp, *p;
+ size_t len;
+
+ if (a == NULL || *a == '\0')
+ return strdup(b);
+ if (b == NULL || *b == '\0')
+ return strdup(a);
+ if (strlen(b) > 1024*1024)
+ return NULL;
+ len = strlen(a) + strlen(b) + 2;
+ if ((tmp = cp = strdup(b)) == NULL ||
+ (ret = calloc(1, len)) == NULL) {
+ free(tmp);
+ return NULL;
+ }
+ strlcpy(ret, a, len);
+ for ((p = strsep(&cp, ",")); p && *p != '\0'; (p = strsep(&cp, ","))) {
+ if (kex_has_any_alg(ret, p))
+ continue; /* Algorithm already present */
+ if (strlcat(ret, ",", len) >= len ||
+ strlcat(ret, p, len) >= len) {
+ free(tmp);
+ free(ret);
+ return NULL; /* Shouldn't happen */
+ }
+ }
+ free(tmp);
+ return ret;
+}
+
+/*
+ * Assemble a list of algorithms from a default list and a string from a
+ * configuration file. The user-provided string may begin with '+' to
+ * indicate that it should be appended to the default, '-' that the
+ * specified names should be removed, or '^' that they should be placed
+ * at the head.
+ */
+int
+kex_assemble_names(char **listp, const char *def, const char *all)
+{
+ char *cp, *tmp, *patterns;
+ char *list = NULL, *ret = NULL, *matching = NULL, *opatterns = NULL;
+ int r = SSH_ERR_INTERNAL_ERROR;
+
+ if (listp == NULL || def == NULL || all == NULL)
+ return SSH_ERR_INVALID_ARGUMENT;
+
+ if (*listp == NULL || **listp == '\0') {
+ if ((*listp = strdup(def)) == NULL)
+ return SSH_ERR_ALLOC_FAIL;
+ return 0;
+ }
+
+ list = *listp;
+ *listp = NULL;
+ if (*list == '+') {
+ /* Append names to default list */
+ if ((tmp = kex_names_cat(def, list + 1)) == NULL) {
+ r = SSH_ERR_ALLOC_FAIL;
+ goto fail;
+ }
+ free(list);
+ list = tmp;
+ } else if (*list == '-') {
+ /* Remove names from default list */
+ if ((*listp = match_filter_denylist(def, list + 1)) == NULL) {
+ r = SSH_ERR_ALLOC_FAIL;
+ goto fail;
+ }
+ free(list);
+ /* filtering has already been done */
+ return 0;
+ } else if (*list == '^') {
+ /* Place names at head of default list */
+ if ((tmp = kex_names_cat(list + 1, def)) == NULL) {
+ r = SSH_ERR_ALLOC_FAIL;
+ goto fail;
+ }
+ free(list);
+ list = tmp;
+ } else {
+ /* Explicit list, overrides default - just use "list" as is */
+ }
+
+ /*
+ * The supplied names may be a pattern-list. For the -list case,
+ * the patterns are applied above. For the +list and explicit list
+ * cases we need to do it now.
+ */
+ ret = NULL;
+ if ((patterns = opatterns = strdup(list)) == NULL) {
+ r = SSH_ERR_ALLOC_FAIL;
+ goto fail;
+ }
+ /* Apply positive (i.e. non-negated) patterns from the list */
+ while ((cp = strsep(&patterns, ",")) != NULL) {
+ if (*cp == '!') {
+ /* negated matches are not supported here */
+ r = SSH_ERR_INVALID_ARGUMENT;
+ goto fail;
+ }
+ free(matching);
+ if ((matching = match_filter_allowlist(all, cp)) == NULL) {
+ r = SSH_ERR_ALLOC_FAIL;
+ goto fail;
+ }
+ if ((tmp = kex_names_cat(ret, matching)) == NULL) {
+ r = SSH_ERR_ALLOC_FAIL;
+ goto fail;
+ }
+ free(ret);
+ ret = tmp;
+ }
+ if (ret == NULL || *ret == '\0') {
+ /* An empty name-list is an error */
+ /* XXX better error code? */
+ r = SSH_ERR_INVALID_ARGUMENT;
+ goto fail;
+ }
+
+ /* success */
+ *listp = ret;
+ ret = NULL;
+ r = 0;
+
+ fail:
+ free(matching);
+ free(opatterns);
+ free(list);
+ free(ret);
+ return r;
+}
projects / openbsd / commitdiff