X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/013eab17f87539f6ae8b69338bd6e00fe52aa33f..6a2c4cd8b3908e0d7e28789e83b4dc2b69aaf6d4:/auth2.c

diff --git a/auth2.c b/auth2.c
index ffd70328..e4a3cded 100644
--- a/auth2.c
+++ b/auth2.c
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: auth2.c,v 1.92 2002/05/25 18:51:07 markus Exp $");
+RCSID("$OpenBSD: auth2.c,v 1.105 2004/05/23 23:59:53 dtucker Exp $");
 
 #include "ssh2.h"
 #include "xmalloc.h"
@@ -36,19 +36,36 @@ RCSID("$OpenBSD: auth2.c,v 1.92 2002/05/25 18:51:07 markus Exp $");
 #include "pathnames.h"
 #include "monitor_wrap.h"
 
+#ifdef GSSAPI
+#include "ssh-gss.h"
+#endif
+
 /* import */
 extern ServerOptions options;
 extern u_char *session_id2;
-extern int session_id2_len;
+extern u_int session_id2_len;
 
-Authctxt *x_authctxt = NULL;
-static int one = 1;
+/* methods */
+
+extern Authmethod method_none;
+extern Authmethod method_pubkey;
+extern Authmethod method_passwd;
+extern Authmethod method_kbdint;
+extern Authmethod method_hostbased;
+#ifdef GSSAPI
+extern Authmethod method_gssapi;
+#endif
 
-typedef struct Authmethod Authmethod;
-struct Authmethod {
-	char	*name;
-	int	(*userauth)(Authctxt *authctxt);
-	int	*enabled;
+Authmethod *authmethods[] = {
+	&method_none,
+	&method_pubkey,
+#ifdef GSSAPI
+	&method_gssapi,
+#endif
+	&method_passwd,
+	&method_kbdint,
+	&method_hostbased,
+	NULL
 };
 
 /* protocol */
@@ -60,53 +77,21 @@ static void input_userauth_request(int, u_int32_t, void *);
 static Authmethod *authmethod_lookup(const char *);
 static char *authmethods_get(void);
 int user_key_allowed(struct passwd *, Key *);
-int hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
-
-/* auth */
-
-Authmethod authmethods[] = {
-	{"none",
-		userauth_none,
-		&one},
-	{"publickey",
-		userauth_pubkey,
-		&options.pubkey_authentication},
-	{"password",
-		userauth_passwd,
-		&options.password_authentication},
-	{"keyboard-interactive",
-		userauth_kbdint,
-		&options.kbd_interactive_authentication},
-	{"hostbased",
-		userauth_hostbased,
-		&options.hostbased_authentication},
-	{NULL, NULL, NULL}
-};
 
 /*
  * loop until authctxt->success == TRUE
  */
 
-Authctxt *
-do_authentication2(void)
+void
+do_authentication2(Authctxt *authctxt)
 {
-	Authctxt *authctxt = authctxt_new();
-
-	x_authctxt = authctxt;		/*XXX*/
-
 	/* challenge-response is implemented via keyboard interactive */
 	if (options.challenge_response_authentication)
 		options.kbd_interactive_authentication = 1;
-	if (options.pam_authentication_via_kbd_int)
-		options.kbd_interactive_authentication = 1;
-	if (use_privsep)
-		options.pam_authentication_via_kbd_int = 0;
 
 	dispatch_init(&dispatch_protocol_error);
 	dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
 	dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
-
-	return (authctxt);
 }
 
 static void
@@ -114,7 +99,7 @@ input_service_request(int type, u_int32_t seq, void *ctxt)
 {
 	Authctxt *authctxt = ctxt;
 	u_int len;
-	int accept = 0;
+	int acceptit = 0;
 	char *service = packet_get_string(&len);
 	packet_check_eom();
 
@@ -123,14 +108,14 @@ input_service_request(int type, u_int32_t seq, void *ctxt)
 
 	if (strcmp(service, "ssh-userauth") == 0) {
 		if (!authctxt->success) {
-			accept = 1;
+			acceptit = 1;
 			/* now we can handle user-auth requests */
 			dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
 		}
 	}
 	/* XXX all other service requests are denied */
 
-	if (accept) {
+	if (acceptit) {
 		packet_start(SSH2_MSG_SERVICE_ACCEPT);
 		packet_put_cstring(service);
 		packet_send();
@@ -165,21 +150,24 @@ input_userauth_request(int type, u_int32_t seq, void *ctxt)
 	if (authctxt->attempt++ == 0) {
 		/* setup auth context */
 		authctxt->pw = PRIVSEP(getpwnamallow(user));
+		authctxt->user = xstrdup(user);
 		if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
 			authctxt->valid = 1;
 			debug2("input_userauth_request: setting up authctxt for %s", user);
 #ifdef USE_PAM
-			PRIVSEP(start_pam(authctxt->pw->pw_name));
+			if (options.use_pam)
+				PRIVSEP(start_pam(authctxt));
 #endif
 		} else {
-			log("input_userauth_request: illegal user %s", user);
+			logit("input_userauth_request: illegal user %s", user);
+			authctxt->pw = fakepw();
 #ifdef USE_PAM
-			PRIVSEP(start_pam("NOUSER"));
+			if (options.use_pam)
+				PRIVSEP(start_pam(authctxt));
 #endif
 		}
 		setproctitle("%s%s", authctxt->pw ? user : "unknown",
 		    use_privsep ? " [net]" : "");
-		authctxt->user = xstrdup(user);
 		authctxt->service = xstrdup(service);
 		authctxt->style = style ? xstrdup(style) : NULL;
 		if (use_privsep)
@@ -192,6 +180,12 @@ input_userauth_request(int type, u_int32_t seq, void *ctxt)
 	}
 	/* reset state */
 	auth2_challenge_stop(authctxt);
+
+#ifdef GSSAPI
+	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
+	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
+#endif
+
 	authctxt->postponed = 0;
 
 	/* try to authenticate user */
@@ -222,10 +216,16 @@ userauth_finish(Authctxt *authctxt, int authenticated, char *method)
 		authenticated = 0;
 
 #ifdef USE_PAM
-	if (!use_privsep && authenticated && authctxt->user && 
-	    !do_pam_account(authctxt->user, NULL))
+	if (options.use_pam && authenticated && !PRIVSEP(do_pam_account()))
 		authenticated = 0;
-#endif /* USE_PAM */
+#endif
+
+#ifdef _UNICOS
+	if (authenticated && cray_access_denied(authctxt->user)) {
+		authenticated = 0;
+		fatal("Access denied for user %s.",authctxt->user);
+	}
+#endif /* _UNICOS */
 
 	/* Log before sending the reply */
 	auth_log(authctxt, authenticated, method, " ssh2");
@@ -243,14 +243,8 @@ userauth_finish(Authctxt *authctxt, int authenticated, char *method)
 		/* now we can break out */
 		authctxt->success = 1;
 	} else {
-		if (authctxt->failures++ > AUTH_FAIL_MAX) {
-#ifdef WITH_AIXAUTHENTICATE
-			loginfailed(authctxt->user,
-			    get_canonical_hostname(options.verify_reverse_mapping),
-			    "ssh");
-#endif /* WITH_AIXAUTHENTICATE */
+		if (authctxt->failures++ > options.max_authtries)
 			packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
-		}
 		methods = authmethods_get();
 		packet_start(SSH2_MSG_USERAUTH_FAILURE);
 		packet_put_cstring(methods);
@@ -261,352 +255,25 @@ userauth_finish(Authctxt *authctxt, int authenticated, char *method)
 	}
 }
 
-char *
-auth2_read_banner(void)
-{
-	struct stat st;
-	char *banner = NULL;
-	off_t len, n;
-	int fd;
-
-	if ((fd = open(options.banner, O_RDONLY)) == -1)
-		return (NULL);
-	if (fstat(fd, &st) == -1) {
-		close(fd);
-		return (NULL);
-	}
-	len = st.st_size;
-	banner = xmalloc(len + 1);
-	n = atomicio(read, fd, banner, len);
-	close(fd);
-
-	if (n != len) {
-		free(banner);
-		return (NULL);
-	}
-	banner[n] = '\0';
-	
-	return (banner);
-}
-
-static void
-userauth_banner(void)
-{
-	char *banner = NULL;
-
-	if (options.banner == NULL || (datafellows & SSH_BUG_BANNER))
-		return;
-
-	if ((banner = PRIVSEP(auth2_read_banner())) == NULL)
-		goto done;
-
-	packet_start(SSH2_MSG_USERAUTH_BANNER);
-	packet_put_cstring(banner);
-	packet_put_cstring("");		/* language, unused */
-	packet_send();
-	debug("userauth_banner: sent");
-done:
-	if (banner)
-		xfree(banner);
-	return;
-}
-
-static int
-userauth_none(Authctxt *authctxt)
-{
-	/* disable method "none", only allowed one time */
-	Authmethod *m = authmethod_lookup("none");
-	if (m != NULL)
-		m->enabled = NULL;
-	packet_check_eom();
-	userauth_banner();
-
-	if (authctxt->valid == 0)
-		return(0);
-
-#ifdef HAVE_CYGWIN
-	if (check_nt_auth(1, authctxt->pw) == 0)
-		return(0);
-#endif
-	return PRIVSEP(auth_password(authctxt, ""));
-}
-
-static int
-userauth_passwd(Authctxt *authctxt)
-{
-	char *password;
-	int authenticated = 0;
-	int change;
-	u_int len;
-	change = packet_get_char();
-	if (change)
-		log("password change not supported");
-	password = packet_get_string(&len);
-	packet_check_eom();
-	if (authctxt->valid &&
-#ifdef HAVE_CYGWIN
-	    check_nt_auth(1, authctxt->pw) &&
-#endif
-	    PRIVSEP(auth_password(authctxt, password)) == 1)
-		authenticated = 1;
-	memset(password, 0, len);
-	xfree(password);
-	return authenticated;
-}
-
-static int
-userauth_kbdint(Authctxt *authctxt)
-{
-	int authenticated = 0;
-	char *lang, *devs;
-
-	lang = packet_get_string(NULL);
-	devs = packet_get_string(NULL);
-	packet_check_eom();
-
-	debug("keyboard-interactive devs %s", devs);
-
-	if (options.challenge_response_authentication)
-		authenticated = auth2_challenge(authctxt, devs);
-
-#ifdef USE_PAM
-	if (authenticated == 0 && options.pam_authentication_via_kbd_int)
-		authenticated = auth2_pam(authctxt);
-#endif
-	xfree(devs);
-	xfree(lang);
-#ifdef HAVE_CYGWIN
-	if (check_nt_auth(0, authctxt->pw) == 0)
-		return(0);
-#endif
-	return authenticated;
-}
-
-static int
-userauth_pubkey(Authctxt *authctxt)
-{
-	Buffer b;
-	Key *key = NULL;
-	char *pkalg;
-	u_char *pkblob, *sig;
-	u_int alen, blen, slen;
-	int have_sig, pktype;
-	int authenticated = 0;
-
-	if (!authctxt->valid) {
-		debug2("userauth_pubkey: disabled because of invalid user");
-		return 0;
-	}
-	have_sig = packet_get_char();
-	if (datafellows & SSH_BUG_PKAUTH) {
-		debug2("userauth_pubkey: SSH_BUG_PKAUTH");
-		/* no explicit pkalg given */
-		pkblob = packet_get_string(&blen);
-		buffer_init(&b);
-		buffer_append(&b, pkblob, blen);
-		/* so we have to extract the pkalg from the pkblob */
-		pkalg = buffer_get_string(&b, &alen);
-		buffer_free(&b);
-	} else {
-		pkalg = packet_get_string(&alen);
-		pkblob = packet_get_string(&blen);
-	}
-	pktype = key_type_from_name(pkalg);
-	if (pktype == KEY_UNSPEC) {
-		/* this is perfectly legal */
-		log("userauth_pubkey: unsupported public key algorithm: %s",
-		    pkalg);
-		goto done;
-	}
-	key = key_from_blob(pkblob, blen);
-	if (key == NULL) {
-		error("userauth_pubkey: cannot decode key: %s", pkalg);
-		goto done;
-	}
-	if (key->type != pktype) {
-		error("userauth_pubkey: type mismatch for decoded key "
-		    "(received %d, expected %d)", key->type, pktype);
-		goto done;
-	}
-	if (have_sig) {
-		sig = packet_get_string(&slen);
-		packet_check_eom();
-		buffer_init(&b);
-		if (datafellows & SSH_OLD_SESSIONID) {
-			buffer_append(&b, session_id2, session_id2_len);
-		} else {
-			buffer_put_string(&b, session_id2, session_id2_len);
-		}
-		/* reconstruct packet */
-		buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
-		buffer_put_cstring(&b, authctxt->user);
-		buffer_put_cstring(&b,
-		    datafellows & SSH_BUG_PKSERVICE ?
-		    "ssh-userauth" :
-		    authctxt->service);
-		if (datafellows & SSH_BUG_PKAUTH) {
-			buffer_put_char(&b, have_sig);
-		} else {
-			buffer_put_cstring(&b, "publickey");
-			buffer_put_char(&b, have_sig);
-			buffer_put_cstring(&b, pkalg);
-		}
-		buffer_put_string(&b, pkblob, blen);
-#ifdef DEBUG_PK
-		buffer_dump(&b);
-#endif
-		/* test for correct signature */
-		authenticated = 0;
-		if (PRIVSEP(user_key_allowed(authctxt->pw, key)) &&
-		    PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b),
-				buffer_len(&b))) == 1)
-			authenticated = 1;
-		buffer_clear(&b);
-		xfree(sig);
-	} else {
-		debug("test whether pkalg/pkblob are acceptable");
-		packet_check_eom();
-
-		/* XXX fake reply and always send PK_OK ? */
-		/*
-		 * XXX this allows testing whether a user is allowed
-		 * to login: if you happen to have a valid pubkey this
-		 * message is sent. the message is NEVER sent at all
-		 * if a user is not allowed to login. is this an
-		 * issue? -markus
-		 */
-		if (PRIVSEP(user_key_allowed(authctxt->pw, key))) {
-			packet_start(SSH2_MSG_USERAUTH_PK_OK);
-			packet_put_string(pkalg, alen);
-			packet_put_string(pkblob, blen);
-			packet_send();
-			packet_write_wait();
-			authctxt->postponed = 1;
-		}
-	}
-	if (authenticated != 1)
-		auth_clear_options();
-done:
-	debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg);
-	if (key != NULL)
-		key_free(key);
-	xfree(pkalg);
-	xfree(pkblob);
-#ifdef HAVE_CYGWIN
-	if (check_nt_auth(0, authctxt->pw) == 0)
-		return(0);
-#endif
-	return authenticated;
-}
-
-static int
-userauth_hostbased(Authctxt *authctxt)
-{
-	Buffer b;
-	Key *key = NULL;
-	char *pkalg, *cuser, *chost, *service;
-	u_char *pkblob, *sig;
-	u_int alen, blen, slen;
-	int pktype;
-	int authenticated = 0;
-
-	if (!authctxt->valid) {
-		debug2("userauth_hostbased: disabled because of invalid user");
-		return 0;
-	}
-	pkalg = packet_get_string(&alen);
-	pkblob = packet_get_string(&blen);
-	chost = packet_get_string(NULL);
-	cuser = packet_get_string(NULL);
-	sig = packet_get_string(&slen);
-
-	debug("userauth_hostbased: cuser %s chost %s pkalg %s slen %d",
-	    cuser, chost, pkalg, slen);
-#ifdef DEBUG_PK
-	debug("signature:");
-	buffer_init(&b);
-	buffer_append(&b, sig, slen);
-	buffer_dump(&b);
-	buffer_free(&b);
-#endif
-	pktype = key_type_from_name(pkalg);
-	if (pktype == KEY_UNSPEC) {
-		/* this is perfectly legal */
-		log("userauth_hostbased: unsupported "
-		    "public key algorithm: %s", pkalg);
-		goto done;
-	}
-	key = key_from_blob(pkblob, blen);
-	if (key == NULL) {
-		error("userauth_hostbased: cannot decode key: %s", pkalg);
-		goto done;
-	}
-	if (key->type != pktype) {
-		error("userauth_hostbased: type mismatch for decoded key "
-		    "(received %d, expected %d)", key->type, pktype);
-		goto done;
-	}
-	service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
-	    authctxt->service;
-	buffer_init(&b);
-	buffer_put_string(&b, session_id2, session_id2_len);
-	/* reconstruct packet */
-	buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
-	buffer_put_cstring(&b, authctxt->user);
-	buffer_put_cstring(&b, service);
-	buffer_put_cstring(&b, "hostbased");
-	buffer_put_string(&b, pkalg, alen);
-	buffer_put_string(&b, pkblob, blen);
-	buffer_put_cstring(&b, chost);
-	buffer_put_cstring(&b, cuser);
-#ifdef DEBUG_PK
-	buffer_dump(&b);
-#endif
-	/* test for allowed key and correct signature */
-	authenticated = 0;
-	if (PRIVSEP(hostbased_key_allowed(authctxt->pw, cuser, chost, key)) &&
-	    PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b),
-			buffer_len(&b))) == 1)
-		authenticated = 1;
-
-	buffer_clear(&b);
-done:
-	debug2("userauth_hostbased: authenticated %d", authenticated);
-	if (key != NULL)
-		key_free(key);
-	xfree(pkalg);
-	xfree(pkblob);
-	xfree(cuser);
-	xfree(chost);
-	xfree(sig);
-	return authenticated;
-}
-
-/* get current user */
-
-struct passwd*
-auth_get_user(void)
-{
-	return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
-}
-
 #define	DELIM	","
 
 static char *
 authmethods_get(void)
 {
-	Authmethod *method = NULL;
 	Buffer b;
 	char *list;
+	int i;
 
 	buffer_init(&b);
-	for (method = authmethods; method->name != NULL; method++) {
-		if (strcmp(method->name, "none") == 0)
+	for (i = 0; authmethods[i] != NULL; i++) {
+		if (strcmp(authmethods[i]->name, "none") == 0)
 			continue;
-		if (method->enabled != NULL && *(method->enabled) != 0) {
+		if (authmethods[i]->enabled != NULL &&
+		    *(authmethods[i]->enabled) != 0) {
 			if (buffer_len(&b) > 0)
 				buffer_append(&b, ",", 1);
-			buffer_append(&b, method->name, strlen(method->name));
+			buffer_append(&b, authmethods[i]->name,
+			    strlen(authmethods[i]->name));
 		}
 	}
 	buffer_append(&b, "\0", 1);
@@ -618,13 +285,15 @@ authmethods_get(void)
 static Authmethod *
 authmethod_lookup(const char *name)
 {
-	Authmethod *method = NULL;
+	int i;
+
 	if (name != NULL)
-		for (method = authmethods; method->name != NULL; method++)
-			if (method->enabled != NULL &&
-			    *(method->enabled) != 0 &&
-			    strcmp(name, method->name) == 0)
-				return method;
-	debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
+		for (i = 0; authmethods[i] != NULL; i++)
+			if (authmethods[i]->enabled != NULL &&
+			    *(authmethods[i]->enabled) != 0 &&
+			    strcmp(name, authmethods[i]->name) == 0)
+				return authmethods[i];
+	debug2("Unrecognized authentication method name: %s",
+	    name ? name : "NULL");
 	return NULL;
 }