upstream: prepare for multiple names for authmethods

allow authentication methods to have one additional name beyond their primary name. allow lookup by this synonym Use primary name for authentication decisions, e.g. for PermitRootLogin=publickey Pass actual invoked name to the authmethods, so they can tell whether they were requested via the their primary name or synonym. ok markus@ OpenBSD-Commit-ID: 9e613fcb44b8168823195602ed3d09ffd7994559
openssh · Dec 19, 2021 · dbb339f · dbb339f
1 parent 39f00dc
commit dbb339f
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Showing 8 changed files with 42 additions and 25 deletions.
diff --git a/auth.h b/auth.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth.h,v 1.101 2020/12/22 00:12:22 djm Exp $ */
+/* $OpenBSD: auth.h,v 1.102 2021/12/19 22:12:07 djm Exp $ */
 
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
@@ -104,7 +104,8 @@ struct Authctxt {
 
 struct Authmethod {
 	char	*name;
-	int	(*userauth)(struct ssh *);
+	char	*synonym;
+	int	(*userauth)(struct ssh *, const char *);
 	int	*enabled;
 };
 

diff --git a/auth2-gss.c b/auth2-gss.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth2-gss.c,v 1.32 2021/01/27 10:15:08 djm Exp $ */
+/* $OpenBSD: auth2-gss.c,v 1.33 2021/12/19 22:12:07 djm Exp $ */
 
 /*
  * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
@@ -60,7 +60,7 @@ static int input_gssapi_errtok(int, u_int32_t, struct ssh *);
  * how to check local user kuserok and the like)
  */
 static int
-userauth_gssapi(struct ssh *ssh)
+userauth_gssapi(struct ssh *ssh, const char *method)
 {
 	Authctxt *authctxt = ssh->authctxt;
 	gss_OID_desc goid = {0, NULL};
@@ -329,6 +329,7 @@ input_gssapi_mic(int type, u_int32_t plen, struct ssh *ssh)
 
 Authmethod method_gssapi = {
 	"gssapi-with-mic",
+	NULL,
 	userauth_gssapi,
 	&options.gss_authentication
 };

diff --git a/auth2-hostbased.c b/auth2-hostbased.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth2-hostbased.c,v 1.47 2021/07/23 03:37:52 djm Exp $ */
+/* $OpenBSD: auth2-hostbased.c,v 1.48 2021/12/19 22:12:07 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -57,7 +57,7 @@
 extern ServerOptions options;
 
 static int
-userauth_hostbased(struct ssh *ssh)
+userauth_hostbased(struct ssh *ssh, const char *method)
 {
 	Authctxt *authctxt = ssh->authctxt;
 	struct sshbuf *b;
@@ -132,7 +132,7 @@ userauth_hostbased(struct ssh *ssh)
 	    (r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
 	    (r = sshbuf_put_cstring(b, authctxt->user)) != 0 ||
 	    (r = sshbuf_put_cstring(b, authctxt->service)) != 0 ||
-	    (r = sshbuf_put_cstring(b, "hostbased")) != 0 ||
+	    (r = sshbuf_put_cstring(b, method)) != 0 ||
 	    (r = sshbuf_put_string(b, pkalg, alen)) != 0 ||
 	    (r = sshbuf_put_string(b, pkblob, blen)) != 0 ||
 	    (r = sshbuf_put_cstring(b, chost)) != 0 ||
@@ -255,6 +255,7 @@ hostbased_key_allowed(struct ssh *ssh, struct passwd *pw,
 
 Authmethod method_hostbased = {
 	"hostbased",
+	NULL,
 	userauth_hostbased,
 	&options.hostbased_authentication
 };
diff --git a/auth2-kbdint.c b/auth2-kbdint.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth2-kbdint.c,v 1.13 2021/07/02 05:11:20 dtucker Exp $ */
+/* $OpenBSD: auth2-kbdint.c,v 1.14 2021/12/19 22:12:07 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -44,7 +44,7 @@
 extern ServerOptions options;
 
 static int
-userauth_kbdint(struct ssh *ssh)
+userauth_kbdint(struct ssh *ssh, const char *method)
 {
 	int r, authenticated = 0;
 	char *lang, *devs;
@@ -66,6 +66,7 @@ userauth_kbdint(struct ssh *ssh)
 
 Authmethod method_kbdint = {
 	"keyboard-interactive",
+	NULL,
 	userauth_kbdint,
 	&options.kbd_interactive_authentication
 };
diff --git a/auth2-none.c b/auth2-none.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth2-none.c,v 1.23 2020/10/18 11:32:01 djm Exp $ */
+/* $OpenBSD: auth2-none.c,v 1.24 2021/12/19 22:12:07 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -59,7 +59,7 @@ extern ServerOptions options;
 static int none_enabled = 1;
 
 static int
-userauth_none(struct ssh *ssh)
+userauth_none(struct ssh *ssh, const char *method)
 {
 	int r;
 
@@ -73,6 +73,7 @@ userauth_none(struct ssh *ssh)
 
 Authmethod method_none = {
 	"none",
+	NULL,
 	userauth_none,
 	&none_enabled
 };
diff --git a/auth2-passwd.c b/auth2-passwd.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth2-passwd.c,v 1.19 2020/10/18 11:32:01 djm Exp $ */
+/* $OpenBSD: auth2-passwd.c,v 1.20 2021/12/19 22:12:07 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -49,7 +49,7 @@
 extern ServerOptions options;
 
 static int
-userauth_passwd(struct ssh *ssh)
+userauth_passwd(struct ssh *ssh, const char *method)
 {
 	char *password;
 	int authenticated = 0, r;
@@ -72,6 +72,7 @@ userauth_passwd(struct ssh *ssh)
 
 Authmethod method_passwd = {
 	"password",
+	NULL,
 	userauth_passwd,
 	&options.password_authentication
 };
diff --git a/auth2-pubkey.c b/auth2-pubkey.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth2-pubkey.c,v 1.110 2021/09/29 01:33:32 djm Exp $ */
+/* $OpenBSD: auth2-pubkey.c,v 1.111 2021/12/19 22:12:07 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -86,7 +86,7 @@ format_key(const struct sshkey *key)
 }
 
 static int
-userauth_pubkey(struct ssh *ssh)
+userauth_pubkey(struct ssh *ssh, const char *method)
 {
 	Authctxt *authctxt = ssh->authctxt;
 	struct passwd *pw = authctxt->pw;
@@ -192,7 +192,7 @@ userauth_pubkey(struct ssh *ssh)
 		if ((r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
 		    (r = sshbuf_put_cstring(b, userstyle)) != 0 ||
 		    (r = sshbuf_put_cstring(b, authctxt->service)) != 0 ||
-		    (r = sshbuf_put_cstring(b, "publickey")) != 0 ||
+		    (r = sshbuf_put_cstring(b, method)) != 0 ||
 		    (r = sshbuf_put_u8(b, have_sig)) != 0 ||
 		    (r = sshbuf_put_cstring(b, pkalg)) != 0 ||
 		    (r = sshbuf_put_string(b, pkblob, blen)) != 0)
@@ -1067,6 +1067,7 @@ user_key_allowed(struct ssh *ssh, struct passwd *pw, struct sshkey *key,
 
 Authmethod method_pubkey = {
 	"publickey",
+	NULL,
 	userauth_pubkey,
 	&options.pubkey_authentication
 };
diff --git a/auth2.c b/auth2.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth2.c,v 1.161 2021/04/03 06:18:40 djm Exp $ */
+/* $OpenBSD: auth2.c,v 1.162 2021/12/19 22:12:07 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -331,7 +331,7 @@ input_userauth_request(int type, u_int32_t seq, struct ssh *ssh)
 	m = authmethod_lookup(authctxt, method);
 	if (m != NULL && authctxt->failures < options.max_authtries) {
 		debug2("input_userauth_request: try method %s", method);
-		authenticated =	m->userauth(ssh);
+		authenticated =	m->userauth(ssh, method);
 	}
 	if (!authctxt->authenticated)
 		ensure_minimum_time_since(tstart,
@@ -346,18 +346,26 @@ input_userauth_request(int type, u_int32_t seq, struct ssh *ssh)
 }
 
 void
-userauth_finish(struct ssh *ssh, int authenticated, const char *method,
+userauth_finish(struct ssh *ssh, int authenticated, const char *packet_method,
     const char *submethod)
 {
 	Authctxt *authctxt = ssh->authctxt;
+	Authmethod *m = NULL;
+	const char *method = packet_method;
 	char *methods;
 	int r, partial = 0;
 
-	if (!authctxt->valid && authenticated)
-		fatal("INTERNAL ERROR: authenticated invalid user %s",
-		    authctxt->user);
-	if (authenticated && authctxt->postponed)
-		fatal("INTERNAL ERROR: authenticated and postponed");
+	if (authenticated) {
+		if (!authctxt->valid) {
+			fatal("INTERNAL ERROR: authenticated invalid user %s",
+			    authctxt->user);
+		}
+		if (authctxt->postponed)
+			fatal("INTERNAL ERROR: authenticated and postponed");
+		if ((m = authmethod_lookup(authctxt, method)) == NULL)
+			fatal("INTERNAL ERROR: bad method %s", method);
+		method = m->name; /* prefer primary name to possible synonym */
+	}
 
 	/* Special handling for root */
 	if (authenticated && authctxt->pw->pw_uid == 0 &&
@@ -504,7 +512,9 @@ authmethod_lookup(Authctxt *authctxt, const char *name)
 		for (i = 0; authmethods[i] != NULL; i++)
 			if (authmethods[i]->enabled != NULL &&
 			    *(authmethods[i]->enabled) != 0 &&
-			    strcmp(name, authmethods[i]->name) == 0 &&
+			    (strcmp(name, authmethods[i]->name) == 0 ||
+			    (authmethods[i]->synonym != NULL &&
+			    strcmp(name, authmethods[i]->synonym) == 0)) &&
 			    auth2_method_allowed(authctxt,
 			    authmethods[i]->name, NULL))
 				return authmethods[i];