1 files changed, 134 insertions, 0 deletions
diff --git a/auth2-methods.c b/auth2-methods.c
new file mode 100644
index 0000000..99637a8
--- /dev/null
+++ b/auth2-methods.c
@@ -0,0 +1,134 @@
+/*
+ * 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 "includes.h"
+
+#include <sys/types.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 from 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 is 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. If 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;
+}