From bb6cc07cf4e98d86b38a2011203c6bb724465135 Mon Sep 17 00:00:00 2001
From: Darren Tucker <dtucker@zip.com.au>
Date: Mon, 17 Sep 2012 13:25:06 +1000
Subject:    - dtucker@cvs.openbsd.org 2012/09/13 23:37:36      [servconf.c]   
   Fix comment line length

---
 servconf.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

(limited to 'servconf.c')

diff --git a/servconf.c b/servconf.c
index ee2e531a0..f4b7dd58b 100644
--- a/servconf.c
+++ b/servconf.c
@@ -1,5 +1,5 @@
 
-/* $OpenBSD: servconf.c,v 1.229 2012/07/13 01:35:21 dtucker Exp $ */
+/* $OpenBSD: servconf.c,v 1.230 2012/09/13 23:37:36 dtucker Exp $ */
 /*
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
@@ -618,8 +618,9 @@ out:
 }
 
 /*
- * All of the attributes on a single Match line are ANDed together, so we need to check every
- * attribute and set the result to zero if any attribute does not match.
+ * All of the attributes on a single Match line are ANDed together, so we need
+ * to check every * attribute and set the result to zero if any attribute does
+ * not match.
  */
 static int
 match_cfg_line(char **condition, int line, struct connection_info *ci)
-- 
cgit v1.2.3


From 09d3e1251250dcf45e5434cd474430e4ec5e8639 Mon Sep 17 00:00:00 2001
From: Damien Miller <djm@mindrot.org>
Date: Wed, 31 Oct 2012 08:58:58 +1100
Subject:    - djm@cvs.openbsd.org 2012/10/30 21:29:55      [auth-rsa.c auth.c
 auth.h auth2-pubkey.c servconf.c servconf.h]      [sshd.c sshd_config
 sshd_config.5]      new sshd_config option AuthorizedKeysCommand to support
 fetching      authorized_keys from a command in addition to (or instead of)
 from      the filesystem. The command is run as the target server user unless
      another specified via a new AuthorizedKeysCommandUser option.

     patch originally by jchadima AT redhat.com, reworked by me; feedback
     and ok markus@
---
 ChangeLog      |  10 +++
 auth-rsa.c     |   4 +-
 auth.c         |  53 ++++++++++-----
 auth.h         |   6 +-
 auth2-pubkey.c | 206 +++++++++++++++++++++++++++++++++++++++++++++++++++------
 servconf.c     |  30 ++++++++-
 servconf.h     |   4 +-
 sshd.c         |  11 ++-
 sshd_config    |   5 +-
 sshd_config.5  |  22 +++++-
 10 files changed, 308 insertions(+), 43 deletions(-)

(limited to 'servconf.c')

diff --git a/ChangeLog b/ChangeLog
index 3cd16e480..27ec898b8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,6 +3,16 @@
    - markus@cvs.openbsd.org 2012/10/05 12:34:39
      [sftp.c]
      fix signed vs unsigned warning; feedback & ok: djm@
+   - djm@cvs.openbsd.org 2012/10/30 21:29:55
+     [auth-rsa.c auth.c auth.h auth2-pubkey.c servconf.c servconf.h]
+     [sshd.c sshd_config sshd_config.5]
+     new sshd_config option AuthorizedKeysCommand to support fetching
+     authorized_keys from a command in addition to (or instead of) from
+     the filesystem. The command is run as the target server user unless
+     another specified via a new AuthorizedKeysCommandUser option.
+     
+     patch originally by jchadima AT redhat.com, reworked by me; feedback
+     and ok markus@
 
 20121019
  - (tim) [buildpkg.sh.in] Double up on some backslashes so they end up in
diff --git a/auth-rsa.c b/auth-rsa.c
index 4ab46cd51..2c8a7cb35 100644
--- a/auth-rsa.c
+++ b/auth-rsa.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth-rsa.c,v 1.80 2011/05/23 03:30:07 djm Exp $ */
+/* $OpenBSD: auth-rsa.c,v 1.81 2012/10/30 21:29:54 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -276,6 +276,8 @@ auth_rsa_key_allowed(struct passwd *pw, BIGNUM *client_n, Key **rkey)
 	temporarily_use_uid(pw);
 
 	for (i = 0; !allowed && i < options.num_authkeys_files; i++) {
+		if (strcasecmp(options.authorized_keys_files[i], "none") == 0)
+			continue;
 		file = expand_authorized_keys(
 		    options.authorized_keys_files[i], pw);
 		allowed = rsa_key_allowed_in_file(pw, file, client_n, rkey);
diff --git a/auth.c b/auth.c
index a8cffd5c1..b5e1eefa0 100644
--- a/auth.c
+++ b/auth.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth.c,v 1.96 2012/05/13 01:42:32 dtucker Exp $ */
+/* $OpenBSD: auth.c,v 1.97 2012/10/30 21:29:54 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -409,41 +409,42 @@ check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
 	return host_status;
 }
 
-
 /*
- * Check a given file for security. This is defined as all components
+ * Check a given path for security. This is defined as all components
  * of the path to the file must be owned by either the owner of
  * of the file or root and no directories must be group or world writable.
  *
  * XXX Should any specific check be done for sym links ?
  *
- * Takes an open file descriptor, the file name, a uid and and
+ * Takes an the file name, its stat information (preferably from fstat() to
+ * avoid races), the uid of the expected owner, their home directory and an
  * error buffer plus max size as arguments.
  *
  * Returns 0 on success and -1 on failure
  */
-static int
-secure_filename(FILE *f, const char *file, struct passwd *pw,
-    char *err, size_t errlen)
+int
+auth_secure_path(const char *name, struct stat *stp, const char *pw_dir,
+    uid_t uid, char *err, size_t errlen)
 {
-	uid_t uid = pw->pw_uid;
 	char buf[MAXPATHLEN], homedir[MAXPATHLEN];
 	char *cp;
 	int comparehome = 0;
 	struct stat st;
 
-	if (realpath(file, buf) == NULL) {
-		snprintf(err, errlen, "realpath %s failed: %s", file,
+	if (realpath(name, buf) == NULL) {
+		snprintf(err, errlen, "realpath %s failed: %s", name,
 		    strerror(errno));
 		return -1;
 	}
-	if (realpath(pw->pw_dir, homedir) != NULL)
+	if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL)
 		comparehome = 1;
 
-	/* check the open file to avoid races */
-	if (fstat(fileno(f), &st) < 0 ||
-	    (st.st_uid != 0 && st.st_uid != uid) ||
-	    (st.st_mode & 022) != 0) {
+	if (!S_ISREG(stp->st_mode)) {
+		snprintf(err, errlen, "%s is not a regular file", buf);
+		return -1;
+	}
+	if ((stp->st_uid != 0 && stp->st_uid != uid) ||
+	    (stp->st_mode & 022) != 0) {
 		snprintf(err, errlen, "bad ownership or modes for file %s",
 		    buf);
 		return -1;
@@ -479,6 +480,28 @@ secure_filename(FILE *f, const char *file, struct passwd *pw,
 	return 0;
 }
 
+/*
+ * Version of secure_path() that accepts an open file descriptor to
+ * avoid races.
+ *
+ * Returns 0 on success and -1 on failure
+ */
+static int
+secure_filename(FILE *f, const char *file, struct passwd *pw,
+    char *err, size_t errlen)
+{
+	char buf[MAXPATHLEN];
+	struct stat st;
+
+	/* check the open file to avoid races */
+	if (fstat(fileno(f), &st) < 0) {
+		snprintf(err, errlen, "cannot stat file %s: %s",
+		    buf, strerror(errno));
+		return -1;
+	}
+	return auth_secure_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen);
+}
+
 static FILE *
 auth_openfile(const char *file, struct passwd *pw, int strict_modes,
     int log_missing, char *file_type)
diff --git a/auth.h b/auth.h
index 0d786c4d5..063404167 100644
--- a/auth.h
+++ b/auth.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth.h,v 1.69 2011/05/23 03:30:07 djm Exp $ */
+/* $OpenBSD: auth.h,v 1.70 2012/10/30 21:29:54 djm Exp $ */
 
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
@@ -120,6 +120,10 @@ int	 auth_rhosts_rsa_key_allowed(struct passwd *, char *, char *, Key *);
 int	 hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
 int	 user_key_allowed(struct passwd *, Key *);
 
+struct stat;
+int	 auth_secure_path(const char *, struct stat *, const char *, uid_t,
+    char *, size_t);
+
 #ifdef KRB5
 int	auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client, krb5_data *);
 int	auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt);
diff --git a/auth2-pubkey.c b/auth2-pubkey.c
index 5bccb5d76..ec8f75d57 100644
--- a/auth2-pubkey.c
+++ b/auth2-pubkey.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth2-pubkey.c,v 1.30 2011/09/25 05:44:47 djm Exp $ */
+/* $OpenBSD: auth2-pubkey.c,v 1.31 2012/10/30 21:29:54 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -27,9 +27,13 @@
 
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/wait.h>
 
+#include <errno.h>
 #include <fcntl.h>
+#include <paths.h>
 #include <pwd.h>
+#include <signal.h>
 #include <stdio.h>
 #include <stdarg.h>
 #include <string.h>
@@ -240,7 +244,7 @@ match_principals_file(char *file, struct passwd *pw, struct KeyCert *cert)
 			if (strcmp(cp, cert->principals[i]) == 0) {
 				debug3("matched principal \"%.100s\" "
 				    "from file \"%s\" on line %lu",
-			    	    cert->principals[i], file, linenum);
+				    cert->principals[i], file, linenum);
 				if (auth_parse_options(pw, line_opts,
 				    file, linenum) != 1)
 					continue;
@@ -253,31 +257,22 @@ match_principals_file(char *file, struct passwd *pw, struct KeyCert *cert)
 	fclose(f);
 	restore_uid();
 	return 0;
-}	
+}
 
-/* return 1 if user allows given key */
+/*
+ * Checks whether key is allowed in authorized_keys-format file,
+ * returns 1 if the key is allowed or 0 otherwise.
+ */
 static int
-user_key_allowed2(struct passwd *pw, Key *key, char *file)
+check_authkeys_file(FILE *f, char *file, Key* key, struct passwd *pw)
 {
 	char line[SSH_MAX_PUBKEY_BYTES];
 	const char *reason;
 	int found_key = 0;
-	FILE *f;
 	u_long linenum = 0;
 	Key *found;
 	char *fp;
 
-	/* Temporarily use the user's uid. */
-	temporarily_use_uid(pw);
-
-	debug("trying public key file %s", file);
-	f = auth_openkeyfile(file, pw, options.strict_modes);
-
-	if (!f) {
-		restore_uid();
-		return 0;
-	}
-
 	found_key = 0;
 	found = key_new(key_is_cert(key) ? KEY_UNSPEC : key->type);
 
@@ -370,8 +365,6 @@ user_key_allowed2(struct passwd *pw, Key *key, char *file)
 			break;
 		}
 	}
-	restore_uid();
-	fclose(f);
 	key_free(found);
 	if (!found_key)
 		debug2("key not found");
@@ -433,7 +426,172 @@ user_cert_trusted_ca(struct passwd *pw, Key *key)
 	return ret;
 }
 
-/* check whether given key is in .ssh/authorized_keys* */
+/*
+ * Checks whether key is allowed in file.
+ * returns 1 if the key is allowed or 0 otherwise.
+ */
+static int
+user_key_allowed2(struct passwd *pw, Key *key, char *file)
+{
+	FILE *f;
+	int found_key = 0;
+
+	/* Temporarily use the user's uid. */
+	temporarily_use_uid(pw);
+
+	debug("trying public key file %s", file);
+	if ((f = auth_openkeyfile(file, pw, options.strict_modes)) != NULL) {
+		found_key = check_authkeys_file(f, file, key, pw);
+		fclose(f);
+	}
+
+	restore_uid();
+	return found_key;
+}
+
+/*
+ * Checks whether key is allowed in output of command.
+ * returns 1 if the key is allowed or 0 otherwise.
+ */
+static int
+user_key_command_allowed2(struct passwd *user_pw, Key *key)
+{
+	FILE *f;
+	int ok, found_key = 0;
+	struct passwd *pw;
+	struct stat st;
+	int status, devnull, p[2], i;
+	pid_t pid;
+	char errmsg[512];
+
+	if (options.authorized_keys_command == NULL ||
+	    options.authorized_keys_command[0] != '/')
+		return 0;
+
+	/* If no user specified to run commands the default to target user */
+	if (options.authorized_keys_command_user == NULL)
+		pw = user_pw;
+	else {
+		pw = getpwnam(options.authorized_keys_command_user);
+		if (pw == NULL) {
+			error("AuthorizedKeyCommandUser \"%s\" not found: %s",
+			    options.authorized_keys_command, strerror(errno));
+			return 0;
+		}
+	}
+
+	temporarily_use_uid(pw);
+
+	if (stat(options.authorized_keys_command, &st) < 0) {
+		error("Could not stat AuthorizedKeysCommand \"%s\": %s",
+		    options.authorized_keys_command, strerror(errno));
+		goto out;
+	}
+	if (auth_secure_path(options.authorized_keys_command, &st, NULL, 0,
+	    errmsg, sizeof(errmsg)) != 0) {
+		error("Unsafe AuthorizedKeysCommand: %s", errmsg);
+		goto out;
+	}
+
+	if (pipe(p) != 0) {
+		error("%s: pipe: %s", __func__, strerror(errno));
+		goto out;
+	}
+
+	debug3("Running AuthorizedKeysCommand: \"%s\" as \"%s\"",
+	    options.authorized_keys_command, pw->pw_name);
+
+	/*
+	 * Don't want to call this in the child, where it can fatal() and
+	 * run cleanup_exit() code.
+	 */
+	restore_uid();
+
+	switch ((pid = fork())) {
+	case -1: /* error */
+		error("%s: fork: %s", __func__, strerror(errno));
+		close(p[0]);
+		close(p[1]);
+		return 0;
+	case 0: /* child */
+		for (i = 0; i < NSIG; i++)
+			signal(i, SIG_DFL);
+
+		/* Don't use permanently_set_uid() here to avoid fatal() */
+		if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0) {
+			error("setresgid %u: %s", (u_int)pw->pw_gid,
+			    strerror(errno));
+			_exit(1);
+		}
+		if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0) {
+			error("setresuid %u: %s", (u_int)pw->pw_uid,
+			    strerror(errno));
+			_exit(1);
+		}
+
+		close(p[0]);
+		if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
+			error("%s: open %s: %s", __func__, _PATH_DEVNULL,
+			    strerror(errno));
+			_exit(1);
+		}
+		if (dup2(devnull, STDIN_FILENO) == -1 ||
+		    dup2(p[1], STDOUT_FILENO) == -1 ||
+		    dup2(devnull, STDERR_FILENO) == -1) {
+			error("%s: dup2: %s", __func__, strerror(errno));
+			_exit(1);
+		}
+		closefrom(STDERR_FILENO + 1);
+
+		execl(options.authorized_keys_command,
+		    options.authorized_keys_command, pw->pw_name, NULL);
+
+		error("AuthorizedKeysCommand %s exec failed: %s",
+		    options.authorized_keys_command, strerror(errno));
+		_exit(127);
+	default: /* parent */
+		break;
+	}
+
+	temporarily_use_uid(pw);
+
+	close(p[1]);
+	if ((f = fdopen(p[0], "r")) == NULL) {
+		error("%s: fdopen: %s", __func__, strerror(errno));
+		close(p[0]);
+		/* Don't leave zombie child */
+		kill(pid, SIGTERM);
+		while (waitpid(pid, NULL, 0) == -1 && errno == EINTR)
+			;
+		goto out;
+	}
+	ok = check_authkeys_file(f, options.authorized_keys_command, key, pw);
+	fclose(f);
+
+	while (waitpid(pid, &status, 0) == -1) {
+		if (errno != EINTR) {
+			error("%s: waitpid: %s", __func__, strerror(errno));
+			goto out;
+		}
+	}
+	if (WIFSIGNALED(status)) {
+		error("AuthorizedKeysCommand %s exited on signal %d",
+		    options.authorized_keys_command, WTERMSIG(status));
+		goto out;
+	} else if (WEXITSTATUS(status) != 0) {
+		error("AuthorizedKeysCommand %s returned status %d",
+		    options.authorized_keys_command, WEXITSTATUS(status));
+		goto out;
+	}
+	found_key = ok;
+ out:
+	restore_uid();
+	return found_key;
+}
+
+/*
+ * Check whether key authenticates and authorises the user.
+ */
 int
 user_key_allowed(struct passwd *pw, Key *key)
 {
@@ -449,9 +607,17 @@ user_key_allowed(struct passwd *pw, Key *key)
 	if (success)
 		return success;
 
+	success = user_key_command_allowed2(pw, key);
+	if (success > 0)
+		return success;
+
 	for (i = 0; !success && i < options.num_authkeys_files; i++) {
+
+		if (strcasecmp(options.authorized_keys_files[i], "none") == 0)
+			continue;
 		file = expand_authorized_keys(
 		    options.authorized_keys_files[i], pw);
+
 		success = user_key_allowed2(pw, key, file);
 		xfree(file);
 	}
diff --git a/servconf.c b/servconf.c
index f4b7dd58b..8e69ea5ce 100644
--- a/servconf.c
+++ b/servconf.c
@@ -1,5 +1,5 @@
 
-/* $OpenBSD: servconf.c,v 1.230 2012/09/13 23:37:36 dtucker Exp $ */
+/* $OpenBSD: servconf.c,v 1.231 2012/10/30 21:29:54 djm Exp $ */
 /*
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
@@ -135,6 +135,8 @@ initialize_server_options(ServerOptions *options)
 	options->num_permitted_opens = -1;
 	options->adm_forced_command = NULL;
 	options->chroot_directory = NULL;
+	options->authorized_keys_command = NULL;
+	options->authorized_keys_command_user = NULL;
 	options->zero_knowledge_password_authentication = -1;
 	options->revoked_keys_file = NULL;
 	options->trusted_user_ca_keys = NULL;
@@ -329,6 +331,7 @@ typedef enum {
 	sZeroKnowledgePasswordAuthentication, sHostCertificate,
 	sRevokedKeys, sTrustedUserCAKeys, sAuthorizedPrincipalsFile,
 	sKexAlgorithms, sIPQoS, sVersionAddendum,
+	sAuthorizedKeysCommand, sAuthorizedKeysCommandUser,
 	sDeprecated, sUnsupported
 } ServerOpCodes;
 
@@ -453,6 +456,8 @@ static struct {
 	{ "authorizedprincipalsfile", sAuthorizedPrincipalsFile, SSHCFG_ALL },
 	{ "kexalgorithms", sKexAlgorithms, SSHCFG_GLOBAL },
 	{ "ipqos", sIPQoS, SSHCFG_ALL },
+	{ "authorizedkeyscommand", sAuthorizedKeysCommand, SSHCFG_ALL },
+	{ "authorizedkeyscommanduser", sAuthorizedKeysCommandUser, SSHCFG_ALL },
 	{ "versionaddendum", sVersionAddendum, SSHCFG_GLOBAL },
 	{ NULL, sBadOption, 0 }
 };
@@ -1498,6 +1503,25 @@ process_server_config_line(ServerOptions *options, char *line,
 		}
 		return 0;
 
+	case sAuthorizedKeysCommand:
+		len = strspn(cp, WHITESPACE);
+		if (*activep && options->authorized_keys_command == NULL) {
+			if (cp[len] != '/' && strcasecmp(cp + len, "none") != 0)
+				fatal("%.200s line %d: AuthorizedKeysCommand "
+				    "must be an absolute path",
+				    filename, linenum);
+			options->authorized_keys_command = xstrdup(cp + len);
+		}
+		return 0;
+
+	case sAuthorizedKeysCommandUser:
+		charptr = &options->authorized_keys_command_user;
+
+		arg = strdelim(&cp);
+		if (*activep && *charptr == NULL)
+			*charptr = xstrdup(arg);
+		break;
+
 	case sDeprecated:
 		logit("%s line %d: Deprecated option %s",
 		    filename, linenum, arg);
@@ -1648,6 +1672,8 @@ copy_set_server_options(ServerOptions *dst, ServerOptions *src, int preauth)
 	M_CP_INTOPT(hostbased_uses_name_from_packet_only);
 	M_CP_INTOPT(kbd_interactive_authentication);
 	M_CP_INTOPT(zero_knowledge_password_authentication);
+	M_CP_STROPT(authorized_keys_command);
+	M_CP_STROPT(authorized_keys_command_user);
 	M_CP_INTOPT(permit_root_login);
 	M_CP_INTOPT(permit_empty_passwd);
 
@@ -1908,6 +1934,8 @@ dump_config(ServerOptions *o)
 	dump_cfg_string(sAuthorizedPrincipalsFile,
 	    o->authorized_principals_file);
 	dump_cfg_string(sVersionAddendum, o->version_addendum);
+	dump_cfg_string(sAuthorizedKeysCommand, o->authorized_keys_command);
+	dump_cfg_string(sAuthorizedKeysCommandUser, o->authorized_keys_command_user);
 
 	/* string arguments requiring a lookup */
 	dump_cfg_string(sLogLevel, log_level_name(o->log_level));
diff --git a/servconf.h b/servconf.h
index 096d596d7..0064c9bc5 100644
--- a/servconf.h
+++ b/servconf.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: servconf.h,v 1.103 2012/07/10 02:19:15 djm Exp $ */
+/* $OpenBSD: servconf.h,v 1.104 2012/10/30 21:29:55 djm Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -166,6 +166,8 @@ typedef struct {
 	char   *revoked_keys_file;
 	char   *trusted_user_ca_keys;
 	char   *authorized_principals_file;
+	char   *authorized_keys_command;
+	char   *authorized_keys_command_user;
 
 	char   *version_addendum;	/* Appended to SSH banner */
 }       ServerOptions;
diff --git a/sshd.c b/sshd.c
index 9aff5e8af..eff0290b0 100644
--- a/sshd.c
+++ b/sshd.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshd.c,v 1.393 2012/07/10 02:19:15 djm Exp $ */
+/* $OpenBSD: sshd.c,v 1.394 2012/10/30 21:29:55 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -359,6 +359,15 @@ grace_alarm_handler(int sig)
 	if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
 		kill(pmonitor->m_pid, SIGALRM);
 
+	/*
+	 * Try to kill any processes that we have spawned, E.g. authorized
+	 * keys command helpers.
+	 */
+	if (getpgid(0) == getpid()) {
+		signal(SIGTERM, SIG_IGN);
+		killpg(0, SIGTERM);
+	}
+
 	/* Log error and exit. */
 	sigdie("Timeout before authentication for %s", get_remote_ipaddr());
 }
diff --git a/sshd_config b/sshd_config
index 9424ee2c6..3d35bef02 100644
--- a/sshd_config
+++ b/sshd_config
@@ -1,4 +1,4 @@
-#	$OpenBSD: sshd_config,v 1.87 2012/07/10 02:19:15 djm Exp $
+#	$OpenBSD: sshd_config,v 1.88 2012/10/30 21:29:55 djm Exp $
 
 # This is the sshd server system-wide configuration file.  See
 # sshd_config(5) for more information.
@@ -51,6 +51,9 @@ AuthorizedKeysFile	.ssh/authorized_keys
 
 #AuthorizedPrincipalsFile none
 
+#AuthorizedKeysCommand none
+#AuthorizedKeysCommandUser nobody
+
 # For this to work you will also need host keys in /etc/ssh/ssh_known_hosts
 #RhostsRSAAuthentication no
 # similar for protocol version 2
diff --git a/sshd_config.5 b/sshd_config.5
index 987558ae8..de8f0f825 100644
--- a/sshd_config.5
+++ b/sshd_config.5
@@ -33,8 +33,8 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.\" $OpenBSD: sshd_config.5,v 1.145 2012/10/04 13:21:50 markus Exp $
-.Dd $Mdocdate: October 4 2012 $
+.\" $OpenBSD: sshd_config.5,v 1.146 2012/10/30 21:29:55 djm Exp $
+.Dd $Mdocdate: October 30 2012 $
 .Dt SSHD_CONFIG 5
 .Os
 .Sh NAME
@@ -151,6 +151,22 @@ See
 in
 .Xr ssh_config 5
 for more information on patterns.
+.It Cm AuthorizedKeysCommand
+Specifies a program to be used for lookup of the user's public keys.
+The program will be invoked with a single argument of the username
+being authenticated, and should produce on standard output zero or
+more lines of authorized_keys output (see AUTHORIZED_KEYS in
+.Xr sshd 8 )
+If a key supplied by AuthorizedKeysCommand does not successfully authenticate
+and authorize the user then public key authentication continues using the usual
+.Cm AuthorizedKeysFile
+files.
+By default, no AuthorizedKeysCommand is run.
+.It Cm AuthorizedKeysCommandUser
+Specifies the user under whose account the AuthorizedKeysCommand is run.
+The default is the user being authenticated.
+It is recommended to use a dedicated user that has no other role on the host
+than running authorized keys commands.
 .It Cm AuthorizedKeysFile
 Specifies the file that contains the public keys that can be used
 for user authentication.
@@ -712,6 +728,8 @@ Available keywords are
 .Cm AllowTcpForwarding ,
 .Cm AllowUsers ,
 .Cm AuthorizedKeysFile ,
+.Cm AuthorizedKeysCommand ,
+.Cm AuthorizedKeysCommandUser ,
 .Cm AuthorizedPrincipalsFile ,
 .Cm Banner ,
 .Cm ChrootDirectory ,
-- 
cgit v1.2.3


From a6e3f01d1e230b8acfdd6b4cf3096459d2a325e0 Mon Sep 17 00:00:00 2001
From: Damien Miller <djm@mindrot.org>
Date: Sun, 4 Nov 2012 23:21:40 +1100
Subject:    - djm@cvs.openbsd.org 2012/11/04 11:09:15      [auth.h auth1.c
 auth2.c monitor.c servconf.c servconf.h sshd.c]      [sshd_config.5]     
 Support multiple required authentication via an AuthenticationMethods     
 option. This option lists one or more comma-separated lists of     
 authentication method names. Successful completion of all the methods in     
 any list is required for authentication to complete;      feedback and ok
 markus@

---
 ChangeLog     |   8 +++
 auth.h        |   7 +-
 auth1.c       |   7 +-
 auth2.c       | 218 +++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 monitor.c     |  35 ++++++++--
 servconf.c    |  26 ++++++-
 servconf.h    |   7 +-
 sshd.c        |  23 ++++++-
 sshd_config.5 |  25 ++++++-
 9 files changed, 328 insertions(+), 28 deletions(-)

(limited to 'servconf.c')

diff --git a/ChangeLog b/ChangeLog
index 120c132af..85c92eb7f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,6 +7,14 @@
      [auth2-pubkey.c sshd.c sshd_config.5]
      Remove default of AuthorizedCommandUser. Administrators are now expected
      to explicitly specify a user. feedback and ok markus@
+   - djm@cvs.openbsd.org 2012/11/04 11:09:15
+     [auth.h auth1.c auth2.c monitor.c servconf.c servconf.h sshd.c]
+     [sshd_config.5]
+     Support multiple required authentication via an AuthenticationMethods
+     option. This option lists one or more comma-separated lists of
+     authentication method names. Successful completion of all the methods in
+     any list is required for authentication to complete;
+     feedback and ok markus@
 
 20121030
  - (djm) OpenBSD CVS Sync
diff --git a/auth.h b/auth.h
index 063404167..8920c7dae 100644
--- a/auth.h
+++ b/auth.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth.h,v 1.70 2012/10/30 21:29:54 djm Exp $ */
+/* $OpenBSD: auth.h,v 1.71 2012/11/04 11:09:15 djm Exp $ */
 
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
@@ -64,6 +64,8 @@ struct Authctxt {
 #ifdef BSD_AUTH
 	auth_session_t	*as;
 #endif
+	char		**auth_methods;	/* modified from server config */
+	u_int		 num_auth_methods;
 #ifdef KRB5
 	krb5_context	 krb5_ctx;
 	krb5_ccache	 krb5_fwd_ccache;
@@ -152,6 +154,9 @@ void	userauth_send_banner(const char *);
 int	auth_root_allowed(char *);
 
 char	*auth2_read_banner(void);
+int	 auth2_methods_valid(const char *, int);
+int	 auth2_update_methods_lists(Authctxt *, const char *);
+int	 auth2_setup_methods_lists(Authctxt *);
 
 void	privsep_challenge_enable(void);
 
diff --git a/auth1.c b/auth1.c
index cc85aec74..fb37fadfe 100644
--- a/auth1.c
+++ b/auth1.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth1.c,v 1.75 2010/08/31 09:58:37 djm Exp $ */
+/* $OpenBSD: auth1.c,v 1.76 2012/11/04 11:09:15 djm Exp $ */
 /*
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
@@ -406,6 +406,11 @@ do_authentication(Authctxt *authctxt)
 		authctxt->pw = fakepw();
 	}
 
+	/* Configuration may have changed as a result of Match */
+	if (options.num_auth_methods != 0)
+		fatal("AuthenticationMethods is not supported with SSH "
+		    "protocol 1");
+
 	setproctitle("%s%s", authctxt->valid ? user : "unknown",
 	    use_privsep ? " [net]" : "");
 
diff --git a/auth2.c b/auth2.c
index b66bef64c..8114ec863 100644
--- a/auth2.c
+++ b/auth2.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth2.c,v 1.124 2011/12/07 05:44:38 djm Exp $ */
+/* $OpenBSD: auth2.c,v 1.125 2012/11/04 11:09:15 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -96,8 +96,10 @@ static void input_service_request(int, u_int32_t, void *);
 static void input_userauth_request(int, u_int32_t, void *);
 
 /* helper */
-static Authmethod *authmethod_lookup(const char *);
-static char *authmethods_get(void);
+static Authmethod *authmethod_lookup(Authctxt *, const char *);
+static char *authmethods_get(Authctxt *authctxt);
+static int method_allowed(Authctxt *, const char *);
+static int list_starts_with(const char *, const char *);
 
 char *
 auth2_read_banner(void)
@@ -255,6 +257,8 @@ input_userauth_request(int type, u_int32_t seq, void *ctxt)
 		if (use_privsep)
 			mm_inform_authserv(service, style);
 		userauth_banner();
+		if (auth2_setup_methods_lists(authctxt) != 0)
+			packet_disconnect("no authentication methods enabled");
 	} else if (strcmp(user, authctxt->user) != 0 ||
 	    strcmp(service, authctxt->service) != 0) {
 		packet_disconnect("Change of username or service not allowed: "
@@ -277,7 +281,7 @@ input_userauth_request(int type, u_int32_t seq, void *ctxt)
 	authctxt->server_caused_failure = 0;
 
 	/* try to authenticate user */
-	m = authmethod_lookup(method);
+	m = authmethod_lookup(authctxt, method);
 	if (m != NULL && authctxt->failures < options.max_authtries) {
 		debug2("input_userauth_request: try method %s", method);
 		authenticated =	m->userauth(authctxt);
@@ -293,6 +297,7 @@ void
 userauth_finish(Authctxt *authctxt, int authenticated, char *method)
 {
 	char *methods;
+	int partial = 0;
 
 	if (!authctxt->valid && authenticated)
 		fatal("INTERNAL ERROR: authenticated invalid user %s",
@@ -335,7 +340,13 @@ userauth_finish(Authctxt *authctxt, int authenticated, char *method)
 	if (authctxt->postponed)
 		return;
 
-	/* XXX todo: check if multiple auth methods are needed */
+	if (authenticated && options.num_auth_methods != 0) {
+		if (!auth2_update_methods_lists(authctxt, method)) {
+			authenticated = 0;
+			partial = 1;
+		}
+	}
+
 	if (authenticated == 1) {
 		/* turn off userauth */
 		dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
@@ -356,34 +367,61 @@ userauth_finish(Authctxt *authctxt, int authenticated, char *method)
 #endif
 			packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
 		}
-		methods = authmethods_get();
+		methods = authmethods_get(authctxt);
+		debug3("%s: failure partial=%d next methods=\"%s\"", __func__,
+		    partial, methods);
 		packet_start(SSH2_MSG_USERAUTH_FAILURE);
 		packet_put_cstring(methods);
-		packet_put_char(0);	/* XXX partial success, unused */
+		packet_put_char(partial);
 		packet_send();
 		packet_write_wait();
 		xfree(methods);
 	}
 }
 
+/*
+ * Checks whether method is allowed by at least one AuthenticationMethods
+ * methods list. Returns 1 if allowed, or no methods lists configured.
+ * 0 otherwise.
+ */
+static int
+method_allowed(Authctxt *authctxt, const char *method)
+{
+	u_int i;
+
+	/*
+	 * NB. authctxt->num_auth_methods might be zero as a result of
+	 * auth2_setup_methods_lists(), so check the configuration.
+	 */
+	if (options.num_auth_methods == 0)
+		return 1;
+	for (i = 0; i < authctxt->num_auth_methods; i++) {
+		if (list_starts_with(authctxt->auth_methods[i], method))
+			return 1;
+	}
+	return 0;
+}
+
 static char *
-authmethods_get(void)
+authmethods_get(Authctxt *authctxt)
 {
 	Buffer b;
 	char *list;
-	int i;
+	u_int i;
 
 	buffer_init(&b);
 	for (i = 0; authmethods[i] != NULL; i++) {
 		if (strcmp(authmethods[i]->name, "none") == 0)
 			continue;
-		if (authmethods[i]->enabled != NULL &&
-		    *(authmethods[i]->enabled) != 0) {
-			if (buffer_len(&b) > 0)
-				buffer_append(&b, ",", 1);
-			buffer_append(&b, authmethods[i]->name,
-			    strlen(authmethods[i]->name));
-		}
+		if (authmethods[i]->enabled == NULL ||
+		    *(authmethods[i]->enabled) == 0)
+			continue;
+		if (!method_allowed(authctxt, authmethods[i]->name))
+			continue;
+		if (buffer_len(&b) > 0)
+			buffer_append(&b, ",", 1);
+		buffer_append(&b, authmethods[i]->name,
+		    strlen(authmethods[i]->name));
 	}
 	buffer_append(&b, "\0", 1);
 	list = xstrdup(buffer_ptr(&b));
@@ -392,7 +430,7 @@ authmethods_get(void)
 }
 
 static Authmethod *
-authmethod_lookup(const char *name)
+authmethod_lookup(Authctxt *authctxt, const char *name)
 {
 	int i;
 
@@ -400,10 +438,154 @@ authmethod_lookup(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 &&
+			    method_allowed(authctxt, authmethods[i]->name))
 				return authmethods[i];
 	debug2("Unrecognized authentication method name: %s",
 	    name ? name : "NULL");
 	return 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;
+	u_int i, found;
+	int ret = -1;
+
+	if (*_methods == '\0') {
+		error("empty authentication method list");
+		return -1;
+	}
+	omethods = methods = xstrdup(_methods);
+	while ((method = strsep(&methods, ",")) != NULL) {
+		for (found = i = 0; !found && authmethods[i] != NULL; i++) {
+			if (strcmp(method, authmethods[i]->name) != 0)
+				continue;
+			if (need_enable) {
+				if (authmethods[i]->enabled == NULL ||
+				    *(authmethods[i]->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;
+}
+
+/*
+ * Prune the AuthenticationMethods supplied in the configuration, removing
+ * any methods lists that include disabled methods. Note that this might
+ * leave authctxt->num_auth_methods == 0, even when multiple required auth
+ * has been requested. For this reason, all tests for whether multiple is
+ * enabled should consult options.num_auth_methods directly.
+ */
+int
+auth2_setup_methods_lists(Authctxt *authctxt)
+{
+	u_int i;
+
+	if (options.num_auth_methods == 0)
+		return 0;
+	debug3("%s: checking methods", __func__);
+	authctxt->auth_methods = xcalloc(options.num_auth_methods,
+	    sizeof(*authctxt->auth_methods));
+	authctxt->num_auth_methods = 0;
+	for (i = 0; i < options.num_auth_methods; i++) {
+		if (auth2_methods_valid(options.auth_methods[i], 1) != 0) {
+			logit("Authentication methods list \"%s\" contains "
+			    "disabled method, skipping",
+			    options.auth_methods[i]);
+			continue;
+		}
+		debug("authentication methods list %d: %s",
+		    authctxt->num_auth_methods, options.auth_methods[i]);
+		authctxt->auth_methods[authctxt->num_auth_methods++] =
+		    xstrdup(options.auth_methods[i]);
+	}
+	if (authctxt->num_auth_methods == 0) {
+		error("No AuthenticationMethods left after eliminating "
+		    "disabled methods");
+		return -1;
+	}
+	return 0;
+}
+
+static int
+list_starts_with(const char *methods, const char *method)
+{
+	size_t l = strlen(method);
+
+	if (strncmp(methods, method, l) != 0)
+		return 0;
+	if (methods[l] != ',' && methods[l] != '\0')
+		return 0;
+	return 1;
+}
+
+/*
+ * Remove method from the start of a comma-separated list of methods.
+ * Returns 0 if the list of methods did not start with that method or 1
+ * if it did.
+ */
+static int
+remove_method(char **methods, const char *method)
+{
+	char *omethods = *methods;
+	size_t l = strlen(method);
+
+	if (!list_starts_with(omethods, method))
+		return 0;
+	*methods = xstrdup(omethods + l + (omethods[l] == ',' ? 1 : 0));
+	free(omethods);
+	return 1;
+}
+
+/*
+ * Called after successful authentication. Will remove the successful method
+ * from the start of each list in which it occurs. If it was the last method
+ * in any list, then authentication is deemed successful.
+ * Returns 1 if the method completed any authentication list or 0 otherwise.
+ */
+int
+auth2_update_methods_lists(Authctxt *authctxt, const char *method)
+{
+	u_int i, found = 0;
+
+	debug3("%s: updating methods list after \"%s\"", __func__, method);
+	for (i = 0; i < authctxt->num_auth_methods; i++) {
+		if (!remove_method(&(authctxt->auth_methods[i]), method))
+			continue;
+		found = 1;
+		if (*authctxt->auth_methods[i] == '\0') {
+			debug2("authentication methods list %d complete", i);
+			return 1;
+		}
+		debug3("authentication methods list %d remaining: \"%s\"",
+		    i, authctxt->auth_methods[i]);
+	}
+	/* This should not happen, but would be bad if it did */
+	if (!found)
+		fatal("%s: method not in AuthenticationMethods", __func__);
+	return 0;
+}
+
+
diff --git a/monitor.c b/monitor.c
index e9802a3fd..0adbf3a65 100644
--- a/monitor.c
+++ b/monitor.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: monitor.c,v 1.117 2012/06/22 12:30:26 dtucker Exp $ */
+/* $OpenBSD: monitor.c,v 1.118 2012/11/04 11:09:15 djm Exp $ */
 /*
  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
  * Copyright 2002 Markus Friedl <markus@openbsd.org>
@@ -381,6 +381,21 @@ monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor)
 	while (!authenticated) {
 		auth_method = "unknown";
 		authenticated = (monitor_read(pmonitor, mon_dispatch, &ent) == 1);
+
+		/* Special handling for multiple required authentications */
+		if (options.num_auth_methods != 0) {
+			if (!compat20)
+				fatal("AuthenticationMethods is not supported"
+				    "with SSH protocol 1");
+			if (authenticated &&
+			    !auth2_update_methods_lists(authctxt,
+			    auth_method)) {
+				debug3("%s: method %s: partial", __func__,
+				    auth_method);
+				authenticated = 0;
+			}
+		}
+
 		if (authenticated) {
 			if (!(ent->flags & MON_AUTHDECIDE))
 				fatal("%s: unexpected authentication from %d",
@@ -401,7 +416,6 @@ monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor)
 			}
 #endif
 		}
-
 		if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) {
 			auth_log(authctxt, authenticated, auth_method,
 			    compat20 ? " ssh2" : "");
@@ -781,7 +795,17 @@ mm_answer_pwnamallow(int sock, Buffer *m)
 	COPY_MATCH_STRING_OPTS();
 #undef M_CP_STROPT
 #undef M_CP_STRARRAYOPT
-	
+
+	/* Create valid auth method lists */
+	if (compat20 && auth2_setup_methods_lists(authctxt) != 0) {
+		/*
+		 * The monitor will continue long enough to let the child
+		 * run to it's packet_disconnect(), but it must not allow any
+		 * authentication to succeed.
+		 */
+		debug("%s: no valid authentication method lists", __func__);
+	}
+
 	debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed);
 	mm_request_send(sock, MONITOR_ANS_PWNAM, m);
 
@@ -918,7 +942,10 @@ mm_answer_bsdauthrespond(int sock, Buffer *m)
 	debug3("%s: sending authenticated: %d", __func__, authok);
 	mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m);
 
-	auth_method = "bsdauth";
+	if (compat20)
+		auth_method = "keyboard-interactive";
+	else
+		auth_method = "bsdauth";
 
 	return (authok != 0);
 }
diff --git a/servconf.c b/servconf.c
index 8e69ea5ce..b90dba63b 100644
--- a/servconf.c
+++ b/servconf.c
@@ -1,5 +1,5 @@
 
-/* $OpenBSD: servconf.c,v 1.231 2012/10/30 21:29:54 djm Exp $ */
+/* $OpenBSD: servconf.c,v 1.232 2012/11/04 11:09:15 djm Exp $ */
 /*
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
@@ -48,6 +48,8 @@
 #include "groupaccess.h"
 #include "canohost.h"
 #include "packet.h"
+#include "hostfile.h"
+#include "auth.h"
 
 static void add_listen_addr(ServerOptions *, char *, int);
 static void add_one_listen_addr(ServerOptions *, char *, int);
@@ -332,6 +334,7 @@ typedef enum {
 	sRevokedKeys, sTrustedUserCAKeys, sAuthorizedPrincipalsFile,
 	sKexAlgorithms, sIPQoS, sVersionAddendum,
 	sAuthorizedKeysCommand, sAuthorizedKeysCommandUser,
+	sAuthenticationMethods,
 	sDeprecated, sUnsupported
 } ServerOpCodes;
 
@@ -459,6 +462,7 @@ static struct {
 	{ "authorizedkeyscommand", sAuthorizedKeysCommand, SSHCFG_ALL },
 	{ "authorizedkeyscommanduser", sAuthorizedKeysCommandUser, SSHCFG_ALL },
 	{ "versionaddendum", sVersionAddendum, SSHCFG_GLOBAL },
+	{ "authenticationmethods", sAuthenticationMethods, SSHCFG_ALL },
 	{ NULL, sBadOption, 0 }
 };
 
@@ -1522,6 +1526,24 @@ process_server_config_line(ServerOptions *options, char *line,
 			*charptr = xstrdup(arg);
 		break;
 
+	case sAuthenticationMethods:
+		if (*activep && options->num_auth_methods == 0) {
+			while ((arg = strdelim(&cp)) && *arg != '\0') {
+				if (options->num_auth_methods >=
+				    MAX_AUTH_METHODS)
+					fatal("%s line %d: "
+					    "too many authentication methods.",
+					    filename, linenum);
+				if (auth2_methods_valid(arg, 0) != 0)
+					fatal("%s line %d: invalid "
+					    "authentication method list.",
+					    filename, linenum);
+				options->auth_methods[
+				    options->num_auth_methods++] = xstrdup(arg);
+			}
+		}
+		return 0;
+
 	case sDeprecated:
 		logit("%s line %d: Deprecated option %s",
 		    filename, linenum, arg);
@@ -1953,6 +1975,8 @@ dump_config(ServerOptions *o)
 	dump_cfg_strarray(sAllowGroups, o->num_allow_groups, o->allow_groups);
 	dump_cfg_strarray(sDenyGroups, o->num_deny_groups, o->deny_groups);
 	dump_cfg_strarray(sAcceptEnv, o->num_accept_env, o->accept_env);
+	dump_cfg_strarray_oneline(sAuthenticationMethods,
+	    o->num_auth_methods, o->auth_methods);
 
 	/* other arguments */
 	for (i = 0; i < o->num_subsystems; i++)
diff --git a/servconf.h b/servconf.h
index 0064c9bc5..68fcdb764 100644
--- a/servconf.h
+++ b/servconf.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: servconf.h,v 1.104 2012/10/30 21:29:55 djm Exp $ */
+/* $OpenBSD: servconf.h,v 1.105 2012/11/04 11:09:15 djm Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -28,6 +28,7 @@
 #define MAX_ACCEPT_ENV		256	/* Max # of env vars. */
 #define MAX_MATCH_GROUPS	256	/* Max # of groups for Match. */
 #define MAX_AUTHKEYS_FILES	256	/* Max # of authorized_keys files. */
+#define MAX_AUTH_METHODS	256	/* Max # of AuthenticationMethods. */
 
 /* permit_root_login */
 #define	PERMIT_NOT_SET		-1
@@ -170,6 +171,9 @@ typedef struct {
 	char   *authorized_keys_command_user;
 
 	char   *version_addendum;	/* Appended to SSH banner */
+
+	u_int	num_auth_methods;
+	char   *auth_methods[MAX_AUTH_METHODS];
 }       ServerOptions;
 
 /* Information about the incoming connection as used by Match */
@@ -199,6 +203,7 @@ struct connection_info {
 		M_CP_STRARRAYOPT(allow_groups, num_allow_groups); \
 		M_CP_STRARRAYOPT(deny_groups, num_deny_groups); \
 		M_CP_STRARRAYOPT(accept_env, num_accept_env); \
+		M_CP_STRARRAYOPT(auth_methods, num_auth_methods); \
 	} while (0)
 
 struct connection_info *get_connection_info(int, int);
diff --git a/sshd.c b/sshd.c
index 4ad1a4bd1..af7ff91ba 100644
--- a/sshd.c
+++ b/sshd.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshd.c,v 1.395 2012/11/04 10:38:43 djm Exp $ */
+/* $OpenBSD: sshd.c,v 1.396 2012/11/04 11:09:15 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -1337,6 +1337,7 @@ main(int ac, char **av)
 	int remote_port;
 	char *line;
 	int config_s[2] = { -1 , -1 };
+	u_int n;
 	u_int64_t ibytes, obytes;
 	mode_t new_umask;
 	Key *key;
@@ -1566,6 +1567,26 @@ main(int ac, char **av)
 		fatal("AuthorizedKeysCommand set without "
 		    "AuthorizedKeysCommandUser");
 
+	/*
+	 * Check whether there is any path through configured auth methods.
+	 * Unfortunately it is not possible to verify this generally before
+	 * daemonisation in the presence of Match block, but this catches
+	 * and warns for trivial misconfigurations that could break login.
+	 */
+	if (options.num_auth_methods != 0) {
+		if ((options.protocol & SSH_PROTO_1))
+			fatal("AuthenticationMethods is not supported with "
+			    "SSH protocol 1");
+		for (n = 0; n < options.num_auth_methods; n++) {
+			if (auth2_methods_valid(options.auth_methods[n],
+			    1) == 0)
+				break;
+		}
+		if (n >= options.num_auth_methods)
+			fatal("AuthenticationMethods cannot be satisfied by "
+			    "enabled authentication methods");
+	}
+
 	/* set default channel AF */
 	channel_set_af(options.address_family);
 
diff --git a/sshd_config.5 b/sshd_config.5
index 0fb0b837d..05f3374fb 100644
--- a/sshd_config.5
+++ b/sshd_config.5
@@ -33,7 +33,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.\" $OpenBSD: sshd_config.5,v 1.148 2012/11/04 10:38:43 djm Exp $
+.\" $OpenBSD: sshd_config.5,v 1.149 2012/11/04 11:09:15 djm Exp $
 .Dd $Mdocdate: November 4 2012 $
 .Dt SSHD_CONFIG 5
 .Os
@@ -151,6 +151,28 @@ See
 in
 .Xr ssh_config 5
 for more information on patterns.
+.It Cm AuthenticationMethods
+Specifies the authentication methods that must be successfully completed
+for a user to be granted access.
+This option must be followed by one or more comma-separated lists of
+authentication method names.
+Successful authentication requires completion of every method in at least
+one of these lists.
+.Pp
+For example, an argument of
+.Dq publickey,password publickey,keyboard-interactive
+would require the user to complete public key authentication, followed by
+either password or keyboard interactive authentication.
+Only methods that are next in one or more lists are offered at each stage,
+so for this example, it would not be possible to attempt password or
+keyboard-interactive authentication before public key.
+.Pp
+This option is only available for SSH protocol 2 and will yield a fatal
+error if enabled if protocol 1 is also enabled.
+Note that each authentication method listed should also be explicitly enabled
+in the configuration.
+The default is not to require multiple authentication; successful completion
+of a single authentication method is sufficient.
 .It Cm AuthorizedKeysCommand
 Specifies a program to be used to look up the user's public keys.
 The program will be invoked with a single argument of the username
@@ -728,6 +750,7 @@ Available keywords are
 .Cm AllowGroups ,
 .Cm AllowTcpForwarding ,
 .Cm AllowUsers ,
+.Cm AuthenticationMethods ,
 .Cm AuthorizedKeysCommand ,
 .Cm AuthorizedKeysCommandUser ,
 .Cm AuthorizedKeysFile ,
-- 
cgit v1.2.3


From aa5b3f831417bac9538d2b6f21d55fef278e8926 Mon Sep 17 00:00:00 2001
From: Damien Miller <djm@mindrot.org>
Date: Mon, 3 Dec 2012 09:50:54 +1100
Subject:    - djm@cvs.openbsd.org 2012/12/02 20:46:11      [auth-options.c
 channels.c servconf.c servconf.h serverloop.c session.c]      [sshd_config.5]
      make AllowTcpForwarding accept "local" and "remote" in addition to its  
    current "yes"/"no" to allow the server to specify whether just local or   
   remote TCP forwarding is enabled. ok markus@

---
 ChangeLog      |  6 ++++++
 auth-options.c |  4 ++--
 channels.c     | 12 +++++-------
 servconf.c     | 18 ++++++++++++++----
 servconf.h     | 10 ++++++++--
 serverloop.c   | 19 +++++++++++++------
 session.c      |  9 ++++++---
 sshd_config.5  | 16 ++++++++++++++--
 8 files changed, 68 insertions(+), 26 deletions(-)

(limited to 'servconf.c')

diff --git a/ChangeLog b/ChangeLog
index 7cea00cb5..cee038727 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -12,6 +12,12 @@
      make deleting explicit keys "ssh-add -d" symmetric with adding keys -
      try to delete the corresponding certificate too and respect the -k option
      to allow deleting of the key only; feedback and ok markus@
+   - djm@cvs.openbsd.org 2012/12/02 20:46:11
+     [auth-options.c channels.c servconf.c servconf.h serverloop.c session.c]
+     [sshd_config.5]
+     make AllowTcpForwarding accept "local" and "remote" in addition to its
+     current "yes"/"no" to allow the server to specify whether just local or
+     remote TCP forwarding is enabled. ok markus@
 
 20121114
  - (djm) OpenBSD CVS Sync
diff --git a/auth-options.c b/auth-options.c
index 0e67bd8c0..23d0423e1 100644
--- a/auth-options.c
+++ b/auth-options.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth-options.c,v 1.56 2011/10/18 04:58:26 djm Exp $ */
+/* $OpenBSD: auth-options.c,v 1.57 2012/12/02 20:46:11 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -349,7 +349,7 @@ auth_parse_options(struct passwd *pw, char *opts, char *file, u_long linenum)
 				xfree(patterns);
 				goto bad_option;
 			}
-			if (options.allow_tcp_forwarding)
+			if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0)
 				channel_add_permitted_opens(host, port);
 			xfree(patterns);
 			goto next_option;
diff --git a/channels.c b/channels.c
index 7791febd7..9cf85a38d 100644
--- a/channels.c
+++ b/channels.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: channels.c,v 1.318 2012/04/23 08:18:17 djm Exp $ */
+/* $OpenBSD: channels.c,v 1.319 2012/12/02 20:46:11 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -3165,12 +3165,10 @@ channel_add_adm_permitted_opens(char *host, int port)
 void
 channel_disable_adm_local_opens(void)
 {
-	if (num_adm_permitted_opens == 0) {
-		permitted_adm_opens = xmalloc(sizeof(*permitted_adm_opens));
-		permitted_adm_opens[num_adm_permitted_opens].host_to_connect
-		   = NULL;
-		num_adm_permitted_opens = 1;
-	}
+	channel_clear_adm_permitted_opens();
+	permitted_adm_opens = xmalloc(sizeof(*permitted_adm_opens));
+	permitted_adm_opens[num_adm_permitted_opens].host_to_connect = NULL;
+	num_adm_permitted_opens = 1;
 }
 
 void
diff --git a/servconf.c b/servconf.c
index b90dba63b..21b371c84 100644
--- a/servconf.c
+++ b/servconf.c
@@ -1,5 +1,5 @@
 
-/* $OpenBSD: servconf.c,v 1.232 2012/11/04 11:09:15 djm Exp $ */
+/* $OpenBSD: servconf.c,v 1.233 2012/12/02 20:46:11 djm Exp $ */
 /*
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
@@ -250,7 +250,7 @@ fill_default_server_options(ServerOptions *options)
 	if (options->compression == -1)
 		options->compression = COMP_DELAYED;
 	if (options->allow_tcp_forwarding == -1)
-		options->allow_tcp_forwarding = 1;
+		options->allow_tcp_forwarding = FORWARD_ALLOW;
 	if (options->allow_agent_forwarding == -1)
 		options->allow_agent_forwarding = 1;
 	if (options->gateway_ports == -1)
@@ -786,6 +786,14 @@ static const struct multistate multistate_privsep[] = {
 	{ "no",				PRIVSEP_OFF },
 	{ NULL, -1 }
 };
+static const struct multistate multistate_tcpfwd[] = {
+	{ "yes",			FORWARD_ALLOW },
+	{ "all",			FORWARD_ALLOW },
+	{ "no",				FORWARD_DENY },
+	{ "remote",			FORWARD_REMOTE },
+	{ "local",			FORWARD_LOCAL },
+	{ NULL, -1 }
+};
 
 int
 process_server_config_line(ServerOptions *options, char *line,
@@ -1143,7 +1151,8 @@ process_server_config_line(ServerOptions *options, char *line,
 
 	case sAllowTcpForwarding:
 		intptr = &options->allow_tcp_forwarding;
-		goto parse_flag;
+		multistate_ptr = multistate_tcpfwd;
+		goto parse_multistate;
 
 	case sAllowAgentForwarding:
 		intptr = &options->allow_agent_forwarding;
@@ -1423,7 +1432,6 @@ process_server_config_line(ServerOptions *options, char *line,
 		}
 		if (strcmp(arg, "none") == 0) {
 			if (*activep && n == -1) {
-				channel_clear_adm_permitted_opens();
 				options->num_permitted_opens = 1;
 				channel_disable_adm_local_opens();
 			}
@@ -1780,6 +1788,8 @@ fmt_intarg(ServerOpCodes code, int val)
 		return fmt_multistate_int(val, multistate_compression);
 	case sUsePrivilegeSeparation:
 		return fmt_multistate_int(val, multistate_privsep);
+	case sAllowTcpForwarding:
+		return fmt_multistate_int(val, multistate_tcpfwd);
 	case sProtocol:
 		switch (val) {
 		case SSH_PROTO_1:
diff --git a/servconf.h b/servconf.h
index 68fcdb764..a23ef7f3a 100644
--- a/servconf.h
+++ b/servconf.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: servconf.h,v 1.105 2012/11/04 11:09:15 djm Exp $ */
+/* $OpenBSD: servconf.h,v 1.106 2012/12/02 20:46:11 djm Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -42,6 +42,12 @@
 #define PRIVSEP_ON		1
 #define PRIVSEP_NOSANDBOX	2
 
+/* AllowTCPForwarding */
+#define FORWARD_DENY		0
+#define FORWARD_REMOTE		(1)
+#define FORWARD_LOCAL		(1<<1)
+#define FORWARD_ALLOW		(FORWARD_REMOTE|FORWARD_LOCAL)
+
 #define DEFAULT_AUTH_FAIL_MAX	6	/* Default for MaxAuthTries */
 #define DEFAULT_SESSIONS_MAX	10	/* Default for MaxSessions */
 
@@ -116,7 +122,7 @@ typedef struct {
 	int     permit_user_env;	/* If true, read ~/.ssh/environment */
 	int     use_login;	/* If true, login(1) is used */
 	int     compression;	/* If true, compression is allowed */
-	int	allow_tcp_forwarding;
+	int	allow_tcp_forwarding; /* One of FORWARD_* */
 	int	allow_agent_forwarding;
 	u_int num_allow_users;
 	char   *allow_users[MAX_ALLOW_USERS];
diff --git a/serverloop.c b/serverloop.c
index 741c5befb..14e60c6dc 100644
--- a/serverloop.c
+++ b/serverloop.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: serverloop.c,v 1.162 2012/06/20 04:42:58 djm Exp $ */
+/* $OpenBSD: serverloop.c,v 1.163 2012/12/02 20:46:11 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -950,7 +950,7 @@ server_input_window_size(int type, u_int32_t seq, void *ctxt)
 static Channel *
 server_request_direct_tcpip(void)
 {
-	Channel *c;
+	Channel *c = NULL;
 	char *target, *originator;
 	u_short target_port, originator_port;
 
@@ -963,9 +963,16 @@ server_request_direct_tcpip(void)
 	debug("server_request_direct_tcpip: originator %s port %d, target %s "
 	    "port %d", originator, originator_port, target, target_port);
 
-	/* XXX check permission */
-	c = channel_connect_to(target, target_port,
-	    "direct-tcpip", "direct-tcpip");
+	/* XXX fine grained permissions */
+	if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0 &&
+	    !no_port_forwarding_flag) {
+		c = channel_connect_to(target, target_port,
+		    "direct-tcpip", "direct-tcpip");
+	} else {
+		logit("refused local port forward: "
+		    "originator %s port %d, target %s port %d",
+		    originator, originator_port, target, target_port);
+	}
 
 	xfree(originator);
 	xfree(target);
@@ -1126,7 +1133,7 @@ server_input_global_request(int type, u_int32_t seq, void *ctxt)
 		    listen_address, listen_port);
 
 		/* check permissions */
-		if (!options.allow_tcp_forwarding ||
+		if ((options.allow_tcp_forwarding & FORWARD_REMOTE) == 0 ||
 		    no_port_forwarding_flag ||
 		    (!want_reply && listen_port == 0)
 #ifndef NO_IPPORT_RESERVED_CONCEPT
diff --git a/session.c b/session.c
index 65bf28776..643e7fc59 100644
--- a/session.c
+++ b/session.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: session.c,v 1.260 2012/03/15 03:10:27 guenther Exp $ */
+/* $OpenBSD: session.c,v 1.261 2012/12/02 20:46:11 djm Exp $ */
 /*
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
@@ -273,7 +273,10 @@ do_authenticated(Authctxt *authctxt)
 	setproctitle("%s", authctxt->pw->pw_name);
 
 	/* setup the channel layer */
-	if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
+	if (no_port_forwarding_flag ||
+	    (options.allow_tcp_forwarding & FORWARD_LOCAL) == 0)
+		channel_disable_adm_local_opens();
+	else
 		channel_permit_all_opens();
 
 	auth_debug_send();
@@ -383,7 +386,7 @@ do_authenticated1(Authctxt *authctxt)
 				debug("Port forwarding not permitted for this authentication.");
 				break;
 			}
-			if (!options.allow_tcp_forwarding) {
+			if (!(options.allow_tcp_forwarding & FORWARD_REMOTE)) {
 				debug("Port forwarding not permitted.");
 				break;
 			}
diff --git a/sshd_config.5 b/sshd_config.5
index 05f3374fb..d2c4db55b 100644
--- a/sshd_config.5
+++ b/sshd_config.5
@@ -33,8 +33,8 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.\" $OpenBSD: sshd_config.5,v 1.149 2012/11/04 11:09:15 djm Exp $
-.Dd $Mdocdate: November 4 2012 $
+.\" $OpenBSD: sshd_config.5,v 1.150 2012/12/02 20:46:11 djm Exp $
+.Dd $Mdocdate: December 2 2012 $
 .Dt SSHD_CONFIG 5
 .Os
 .Sh NAME
@@ -124,6 +124,18 @@ in
 for more information on patterns.
 .It Cm AllowTcpForwarding
 Specifies whether TCP forwarding is permitted.
+The available options are
+.Dq yes
+or
+.Dq all
+to allow TCP forwarding,
+.Dq no
+to prevent all TCP forwarding,
+.Dq local
+to allow local (from the perspective of
+.Xr ssh 1 ) forwarding only or
+.Dq remote
+to allow remote forwarding only.
 The default is
 .Dq yes .
 Note that disabling TCP forwarding does not improve security unless
-- 
cgit v1.2.3


From 1f583df8c3a7a3731a18b17e14c9ec09f31905ba Mon Sep 17 00:00:00 2001
From: Damien Miller <djm@mindrot.org>
Date: Tue, 12 Feb 2013 11:02:08 +1100
Subject:    - dtucker@cvs.openbsd.org 2013/02/06 00:20:42      [servconf.c
 sshd_config sshd_config.5]      Change default of MaxStartups to 10:30:100 to
 start doing random early      drop at 10 connections up to 100 connections. 
 This will make it harder      to DoS as CPUs have come a long way since the
 original value was set      back in 2000.  Prompted by nion at debian org, ok
 markus@

---
 ChangeLog     | 6 ++++++
 servconf.c    | 8 ++++----
 sshd_config   | 4 ++--
 sshd_config.5 | 6 +++---
 4 files changed, 15 insertions(+), 9 deletions(-)

(limited to 'servconf.c')

diff --git a/ChangeLog b/ChangeLog
index b028fef82..2d5f1d96b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -22,6 +22,12 @@
    - djm@cvs.openbsd.org 2013/01/27 10:06:12
      [krl.c]
      actually use the xrealloc() return value; spotted by xi.wang AT gmail.com
+   - dtucker@cvs.openbsd.org 2013/02/06 00:20:42
+     [servconf.c sshd_config sshd_config.5]
+     Change default of MaxStartups to 10:30:100 to start doing random early
+     drop at 10 connections up to 100 connections.  This will make it harder
+     to DoS as CPUs have come a long way since the original value was set
+     back in 2000.  Prompted by nion at debian org, ok markus@
 
 20130211
  - (djm) [configure.ac openbsd-compat/openssl-compat.h] Repair build on old
diff --git a/servconf.c b/servconf.c
index 21b371c84..b2a60fd6c 100644
--- a/servconf.c
+++ b/servconf.c
@@ -1,5 +1,5 @@
 
-/* $OpenBSD: servconf.c,v 1.233 2012/12/02 20:46:11 djm Exp $ */
+/* $OpenBSD: servconf.c,v 1.234 2013/02/06 00:20:42 dtucker Exp $ */
 /*
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
@@ -256,11 +256,11 @@ fill_default_server_options(ServerOptions *options)
 	if (options->gateway_ports == -1)
 		options->gateway_ports = 0;
 	if (options->max_startups == -1)
-		options->max_startups = 10;
+		options->max_startups = 100;
 	if (options->max_startups_rate == -1)
-		options->max_startups_rate = 100;		/* 100% */
+		options->max_startups_rate = 30;		/* 30% */
 	if (options->max_startups_begin == -1)
-		options->max_startups_begin = options->max_startups;
+		options->max_startups_begin = 10;
 	if (options->max_authtries == -1)
 		options->max_authtries = DEFAULT_AUTH_FAIL_MAX;
 	if (options->max_sessions == -1)
diff --git a/sshd_config b/sshd_config
index 3d35bef02..9cd2fddce 100644
--- a/sshd_config
+++ b/sshd_config
@@ -1,4 +1,4 @@
-#	$OpenBSD: sshd_config,v 1.88 2012/10/30 21:29:55 djm Exp $
+#	$OpenBSD: sshd_config,v 1.89 2013/02/06 00:20:42 dtucker Exp $
 
 # This is the sshd server system-wide configuration file.  See
 # sshd_config(5) for more information.
@@ -109,7 +109,7 @@ UsePrivilegeSeparation sandbox		# Default for new installations.
 #ClientAliveCountMax 3
 #UseDNS yes
 #PidFile /var/run/sshd.pid
-#MaxStartups 10
+#MaxStartups 10:30:100
 #PermitTunnel no
 #ChrootDirectory none
 #VersionAddendum none
diff --git a/sshd_config.5 b/sshd_config.5
index d2913c33f..cfa480697 100644
--- a/sshd_config.5
+++ b/sshd_config.5
@@ -33,8 +33,8 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.\" $OpenBSD: sshd_config.5,v 1.155 2013/01/18 08:00:49 jmc Exp $
-.Dd $Mdocdate: January 18 2013 $
+.\" $OpenBSD: sshd_config.5,v 1.156 2013/02/06 00:20:42 dtucker Exp $
+.Dd $Mdocdate: February 6 2013 $
 .Dt SSHD_CONFIG 5
 .Os
 .Sh NAME
@@ -820,7 +820,7 @@ SSH daemon.
 Additional connections will be dropped until authentication succeeds or the
 .Cm LoginGraceTime
 expires for a connection.
-The default is 10.
+The default is 10:30:100.
 .Pp
 Alternatively, random early drop can be enabled by specifying
 the three colon separated values
-- 
cgit v1.2.3