Initial commit

This commit is contained in:
domenico
2025-06-24 15:51:28 +02:00
commit 22031d9dab
6862 changed files with 1462554 additions and 0 deletions

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@@ -0,0 +1,130 @@
From 46b22e57d91e33a591d0fba97da52672af4d6ed2 Mon Sep 17 00:00:00 2001
From: Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>
Date: Mon, 29 May 2017 10:25:09 +0100
Subject: [PATCH] dropbear server: support -T max auth tries
Add support for '-T n' for a run-time specification for maximum number
of authentication attempts where 'n' is between 1 and compile time
option MAX_AUTH_TRIES.
A default number of tries can be specified at compile time using
'DEFAULT_AUTH_TRIES' which itself defaults to MAX_AUTH_TRIES for
backwards compatibility.
Signed-off-by: Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>
---
options.h | 7 +++++++
runopts.h | 1 +
svr-auth.c | 2 +-
svr-runopts.c | 17 +++++++++++++++++
4 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/options.h b/options.h
index 0c51bb1..4d22704 100644
--- a/options.h
+++ b/options.h
@@ -284,6 +284,13 @@ Homedir is prepended unless path begins with / */
#define MAX_AUTH_TRIES 10
#endif
+/* Default maximum number of failed authentication tries.
+ * defaults to MAX_AUTH_TRIES */
+
+#ifndef DEFAULT_AUTH_TRIES
+#define DEFAULT_AUTH_TRIES MAX_AUTH_TRIES
+#endif
+
/* The default file to store the daemon's process ID, for shutdown
scripts etc. This can be overridden with the -P flag */
#ifndef DROPBEAR_PIDFILE
diff --git a/runopts.h b/runopts.h
index f7c869d..2f7da63 100644
--- a/runopts.h
+++ b/runopts.h
@@ -96,6 +96,7 @@ typedef struct svr_runopts {
int noauthpass;
int norootpass;
int allowblankpass;
+ unsigned int maxauthtries;
#ifdef ENABLE_SVR_REMOTETCPFWD
int noremotetcp;
diff --git a/svr-auth.c b/svr-auth.c
index 577ea88..6a7ce0b 100644
--- a/svr-auth.c
+++ b/svr-auth.c
@@ -362,7 +362,7 @@ void send_msg_userauth_failure(int partial, int incrfail) {
ses.authstate.failcount++;
}
- if (ses.authstate.failcount >= MAX_AUTH_TRIES) {
+ if (ses.authstate.failcount >= svr_opts.maxauthtries) {
char * userstr;
/* XXX - send disconnect ? */
TRACE(("Max auth tries reached, exiting"))
diff --git a/svr-runopts.c b/svr-runopts.c
index 8f60059..1e7440f 100644
--- a/svr-runopts.c
+++ b/svr-runopts.c
@@ -73,6 +73,7 @@ static void printhelp(const char * progname) {
"-g Disable password logins for root\n"
"-B Allow blank password logins\n"
#endif
+ "-T <1 to %d> Maximum authentication tries (default %d)\n"
#ifdef ENABLE_SVR_LOCALTCPFWD
"-j Disable local port forwarding\n"
#endif
@@ -106,6 +107,7 @@ static void printhelp(const char * progname) {
#ifdef DROPBEAR_ECDSA
ECDSA_PRIV_FILENAME,
#endif
+ MAX_AUTH_TRIES, DEFAULT_AUTH_TRIES,
DROPBEAR_MAX_PORTS, DROPBEAR_DEFPORT, DROPBEAR_PIDFILE,
DEFAULT_RECV_WINDOW, DEFAULT_KEEPALIVE, DEFAULT_IDLE_TIMEOUT);
}
@@ -118,6 +120,7 @@ void svr_getopts(int argc, char ** argv) {
char* recv_window_arg = NULL;
char* keepalive_arg = NULL;
char* idle_timeout_arg = NULL;
+ char* maxauthtries_arg = NULL;
char* keyfile = NULL;
char c;
@@ -130,6 +133,7 @@ void svr_getopts(int argc, char ** argv) {
svr_opts.noauthpass = 0;
svr_opts.norootpass = 0;
svr_opts.allowblankpass = 0;
+ svr_opts.maxauthtries = DEFAULT_AUTH_TRIES;
svr_opts.inetdmode = 0;
svr_opts.portcount = 0;
svr_opts.hostkey = NULL;
@@ -234,6 +238,9 @@ void svr_getopts(int argc, char ** argv) {
case 'I':
next = &idle_timeout_arg;
break;
+ case 'T':
+ next = &maxauthtries_arg;
+ break;
#if defined(ENABLE_SVR_PASSWORD_AUTH) || defined(ENABLE_SVR_PAM_AUTH)
case 's':
svr_opts.noauthpass = 1;
@@ -330,6 +337,16 @@ void svr_getopts(int argc, char ** argv) {
dropbear_exit("Bad recv window '%s'", recv_window_arg);
}
}
+
+ if (maxauthtries_arg) {
+ unsigned int val = 0;
+ if (m_str_to_uint(maxauthtries_arg, &val) == DROPBEAR_FAILURE ||
+ val == 0 || val > MAX_AUTH_TRIES) {
+ dropbear_exit("Bad maxauthtries '%s'", maxauthtries_arg);
+ }
+ svr_opts.maxauthtries = val;
+ }
+
if (keepalive_arg) {
unsigned int val;
--
2.7.4

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@@ -0,0 +1,221 @@
From 52adbb34c32d3e2e1bcdb941e20a6f81138b8248 Mon Sep 17 00:00:00 2001
From: Matt Johnston <matt@ucc.asn.au>
Date: Thu, 23 Aug 2018 23:43:12 +0800
Subject: [PATCH 2/2] Wait to fail invalid usernames
---
auth.h | 6 +++---
svr-auth.c | 19 +++++--------------
svr-authpam.c | 26 ++++++++++++++++++++++----
svr-authpasswd.c | 27 ++++++++++++++-------------
svr-authpubkey.c | 11 ++++++++++-
5 files changed, 54 insertions(+), 35 deletions(-)
--- a/auth.h
+++ b/auth.h
@@ -37,9 +37,9 @@ void recv_msg_userauth_request(void);
void send_msg_userauth_failure(int partial, int incrfail);
void send_msg_userauth_success(void);
void send_msg_userauth_banner(buffer *msg);
-void svr_auth_password(void);
-void svr_auth_pubkey(void);
-void svr_auth_pam(void);
+void svr_auth_password(int valid_user);
+void svr_auth_pubkey(int valid_user);
+void svr_auth_pam(int valid_user);
#ifdef ENABLE_SVR_PUBKEY_OPTIONS
int svr_pubkey_allows_agentfwd(void);
--- a/svr-auth.c
+++ b/svr-auth.c
@@ -176,10 +176,8 @@ void recv_msg_userauth_request() {
if (methodlen == AUTH_METHOD_PASSWORD_LEN &&
strncmp(methodname, AUTH_METHOD_PASSWORD,
AUTH_METHOD_PASSWORD_LEN) == 0) {
- if (valid_user) {
- svr_auth_password();
- goto out;
- }
+ svr_auth_password(valid_user);
+ goto out;
}
}
#endif
@@ -191,10 +189,8 @@ void recv_msg_userauth_request() {
if (methodlen == AUTH_METHOD_PASSWORD_LEN &&
strncmp(methodname, AUTH_METHOD_PASSWORD,
AUTH_METHOD_PASSWORD_LEN) == 0) {
- if (valid_user) {
- svr_auth_pam();
- goto out;
- }
+ svr_auth_pam(valid_user);
+ goto out;
}
}
#endif
@@ -204,12 +200,7 @@ void recv_msg_userauth_request() {
if (methodlen == AUTH_METHOD_PUBKEY_LEN &&
strncmp(methodname, AUTH_METHOD_PUBKEY,
AUTH_METHOD_PUBKEY_LEN) == 0) {
- if (valid_user) {
- svr_auth_pubkey();
- } else {
- /* pubkey has no failure delay */
- send_msg_userauth_failure(0, 0);
- }
+ svr_auth_pubkey(valid_user);
goto out;
}
#endif
--- a/svr-authpam.c
+++ b/svr-authpam.c
@@ -178,13 +178,14 @@ pamConvFunc(int num_msg,
* Keyboard interactive would be a lot nicer, but since PAM is synchronous, it
* gets very messy trying to send the interactive challenges, and read the
* interactive responses, over the network. */
-void svr_auth_pam() {
+void svr_auth_pam(int valid_user) {
struct UserDataS userData = {NULL, NULL};
struct pam_conv pamConv = {
pamConvFunc,
&userData /* submitted to pamvConvFunc as appdata_ptr */
};
+ const char* printable_user = NULL;
pam_handle_t* pamHandlep = NULL;
@@ -204,12 +205,23 @@ void svr_auth_pam() {
password = buf_getstring(ses.payload, &passwordlen);
+ /* We run the PAM conversation regardless of whether the username is valid
+ in case the conversation function has an inherent delay.
+ Use ses.authstate.username rather than ses.authstate.pw_name.
+ After PAM succeeds we then check the valid_user flag too */
+
/* used to pass data to the PAM conversation function - don't bother with
* strdup() etc since these are touched only by our own conversation
* function (above) which takes care of it */
- userData.user = ses.authstate.pw_name;
+ userData.user = ses.authstate.username;
userData.passwd = password;
+ if (ses.authstate.pw_name) {
+ printable_user = ses.authstate.pw_name;
+ } else {
+ printable_user = "<invalid username>";
+ }
+
/* Init pam */
if ((rc = pam_start("sshd", NULL, &pamConv, &pamHandlep)) != PAM_SUCCESS) {
dropbear_log(LOG_WARNING, "pam_start() failed, rc=%d, %s",
@@ -236,7 +248,7 @@ void svr_auth_pam() {
rc, pam_strerror(pamHandlep, rc));
dropbear_log(LOG_WARNING,
"Bad PAM password attempt for '%s' from %s",
- ses.authstate.pw_name,
+ printable_user,
svr_ses.addrstring);
send_msg_userauth_failure(0, 1);
goto cleanup;
@@ -247,12 +259,18 @@ void svr_auth_pam() {
rc, pam_strerror(pamHandlep, rc));
dropbear_log(LOG_WARNING,
"Bad PAM password attempt for '%s' from %s",
- ses.authstate.pw_name,
+ printable_user,
svr_ses.addrstring);
send_msg_userauth_failure(0, 1);
goto cleanup;
}
+ if (!valid_user) {
+ /* PAM auth succeeded but the username isn't allowed in for another reason
+ (checkusername() failed) */
+ send_msg_userauth_failure(0, 1);
+ }
+
/* successful authentication */
dropbear_log(LOG_NOTICE, "PAM password auth succeeded for '%s' from %s",
ses.authstate.pw_name,
--- a/svr-authpasswd.c
+++ b/svr-authpasswd.c
@@ -48,22 +48,14 @@ static int constant_time_strcmp(const ch
/* Process a password auth request, sending success or failure messages as
* appropriate */
-void svr_auth_password() {
+void svr_auth_password(int valid_user) {
char * passwdcrypt = NULL; /* the crypt from /etc/passwd or /etc/shadow */
char * testcrypt = NULL; /* crypt generated from the user's password sent */
- char * password;
+ char * password = NULL;
unsigned int passwordlen;
-
unsigned int changepw;
- passwdcrypt = ses.authstate.pw_passwd;
-
-#ifdef DEBUG_HACKCRYPT
- /* debugging crypt for non-root testing with shadows */
- passwdcrypt = DEBUG_HACKCRYPT;
-#endif
-
/* check if client wants to change password */
changepw = buf_getbool(ses.payload);
if (changepw) {
@@ -73,12 +65,21 @@ void svr_auth_password() {
}
password = buf_getstring(ses.payload, &passwordlen);
-
- /* the first bytes of passwdcrypt are the salt */
- testcrypt = crypt(password, passwdcrypt);
+ if (valid_user) {
+ /* the first bytes of passwdcrypt are the salt */
+ passwdcrypt = ses.authstate.pw_passwd;
+ testcrypt = crypt(password, passwdcrypt);
+ }
m_burn(password, passwordlen);
m_free(password);
+ /* After we have got the payload contents we can exit if the username
+ is invalid. Invalid users have already been logged. */
+ if (!valid_user) {
+ send_msg_userauth_failure(0, 1);
+ return;
+ }
+
if (testcrypt == NULL) {
/* crypt() with an invalid salt like "!!" */
dropbear_log(LOG_WARNING, "User account '%s' is locked",
--- a/svr-authpubkey.c
+++ b/svr-authpubkey.c
@@ -79,7 +79,7 @@ static int checkfileperm(char * filename
/* process a pubkey auth request, sending success or failure message as
* appropriate */
-void svr_auth_pubkey() {
+void svr_auth_pubkey(int valid_user) {
unsigned char testkey; /* whether we're just checking if a key is usable */
char* algo = NULL; /* pubkey algo */
@@ -102,6 +102,15 @@ void svr_auth_pubkey() {
keybloblen = buf_getint(ses.payload);
keyblob = buf_getptr(ses.payload, keybloblen);
+ if (!valid_user) {
+ /* Return failure once we have read the contents of the packet
+ required to validate a public key.
+ Avoids blind user enumeration though it isn't possible to prevent
+ testing for user existence if the public key is known */
+ send_msg_userauth_failure(0, 0);
+ goto out;
+ }
+
/* check if the key is valid */
if (checkpubkey(algo, algolen, keyblob, keybloblen) == DROPBEAR_FAILURE) {
send_msg_userauth_failure(0, 0);

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@@ -0,0 +1,87 @@
--- a/svr-authpubkey.c
+++ b/svr-authpubkey.c
@@ -229,14 +229,20 @@ static int checkpubkey(char* algo, unsig
goto out;
}
- /* we don't need to check pw and pw_dir for validity, since
- * its been done in checkpubkeyperms. */
- len = strlen(ses.authstate.pw_dir);
- /* allocate max required pathname storage,
- * = path + "/.ssh/authorized_keys" + '\0' = pathlen + 22 */
- filename = m_malloc(len + 22);
- snprintf(filename, len + 22, "%s/.ssh/authorized_keys",
- ses.authstate.pw_dir);
+ if (ses.authstate.pw_uid != 0) {
+ /* we don't need to check pw and pw_dir for validity, since
+ * its been done in checkpubkeyperms. */
+ len = strlen(ses.authstate.pw_dir);
+ /* allocate max required pathname storage,
+ * = path + "/.ssh/authorized_keys" + '\0' = pathlen + 22 */
+ filename = m_malloc(len + 22);
+ snprintf(filename, len + 22, "%s/.ssh/authorized_keys",
+ ses.authstate.pw_dir);
+ } else {
+ filename = m_malloc(30);
+ strncpy(filename, "/etc/dropbear/authorized_keys", 30);
+ }
+
/* open the file as the authenticating user. */
origuid = getuid();
@@ -405,26 +411,35 @@ static int checkpubkeyperms() {
goto out;
}
- /* allocate max required pathname storage,
- * = path + "/.ssh/authorized_keys" + '\0' = pathlen + 22 */
- filename = m_malloc(len + 22);
- strncpy(filename, ses.authstate.pw_dir, len+1);
-
- /* check ~ */
- if (checkfileperm(filename) != DROPBEAR_SUCCESS) {
- goto out;
- }
-
- /* check ~/.ssh */
- strncat(filename, "/.ssh", 5); /* strlen("/.ssh") == 5 */
- if (checkfileperm(filename) != DROPBEAR_SUCCESS) {
- goto out;
- }
-
- /* now check ~/.ssh/authorized_keys */
- strncat(filename, "/authorized_keys", 16);
- if (checkfileperm(filename) != DROPBEAR_SUCCESS) {
- goto out;
+ if (ses.authstate.pw_uid == 0) {
+ if (checkfileperm("/etc/dropbear") != DROPBEAR_SUCCESS) {
+ goto out;
+ }
+ if (checkfileperm("/etc/dropbear/authorized_keys") != DROPBEAR_SUCCESS) {
+ goto out;
+ }
+ } else {
+ /* allocate max required pathname storage,
+ * = path + "/.ssh/authorized_keys" + '\0' = pathlen + 22 */
+ filename = m_malloc(len + 22);
+ strncpy(filename, ses.authstate.pw_dir, len+1);
+
+ /* check ~ */
+ if (checkfileperm(filename) != DROPBEAR_SUCCESS) {
+ goto out;
+ }
+
+ /* check ~/.ssh */
+ strncat(filename, "/.ssh", 5); /* strlen("/.ssh") == 5 */
+ if (checkfileperm(filename) != DROPBEAR_SUCCESS) {
+ goto out;
+ }
+
+ /* now check ~/.ssh/authorized_keys */
+ strncat(filename, "/authorized_keys", 16);
+ if (checkfileperm(filename) != DROPBEAR_SUCCESS) {
+ goto out;
+ }
}
/* file looks ok, return success */

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@@ -0,0 +1,18 @@
--- a/svr-chansession.c
+++ b/svr-chansession.c
@@ -922,12 +922,12 @@ static void execchild(void *user_data) {
/* We can only change uid/gid as root ... */
if (getuid() == 0) {
- if ((setgid(ses.authstate.pw_gid) < 0) ||
+ if ((ses.authstate.pw_gid != 0) && ((setgid(ses.authstate.pw_gid) < 0) ||
(initgroups(ses.authstate.pw_name,
- ses.authstate.pw_gid) < 0)) {
+ ses.authstate.pw_gid) < 0))) {
dropbear_exit("Error changing user group");
}
- if (setuid(ses.authstate.pw_uid) < 0) {
+ if ((ses.authstate.pw_uid != 0) && (setuid(ses.authstate.pw_uid) < 0)) {
dropbear_exit("Error changing user");
}
} else {

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@@ -0,0 +1,82 @@
--- a/options.h
+++ b/options.h
@@ -41,7 +41,7 @@
* Both of these flags can be defined at once, don't compile without at least
* one of them. */
#define NON_INETD_MODE
-#define INETD_MODE
+/*#define INETD_MODE*/
/* Setting this disables the fast exptmod bignum code. It saves ~5kB, but is
* perhaps 20% slower for pubkey operations (it is probably worth experimenting
@@ -81,7 +81,7 @@ much traffic. */
/* Enable "Netcat mode" option. This will forward standard input/output
* to a remote TCP-forwarded connection */
-#define ENABLE_CLI_NETCAT
+/*#define ENABLE_CLI_NETCAT*/
/* Whether to support "-c" and "-m" flags to choose ciphers/MACs at runtime */
#define ENABLE_USER_ALGO_LIST
@@ -91,16 +91,16 @@ much traffic. */
* Including multiple keysize variants the same cipher
* (eg AES256 as well as AES128) will result in a minimal size increase.*/
#define DROPBEAR_AES128
-#define DROPBEAR_3DES
+/*#define DROPBEAR_3DES*/
#define DROPBEAR_AES256
/* Compiling in Blowfish will add ~6kB to runtime heap memory usage */
/*#define DROPBEAR_BLOWFISH*/
-#define DROPBEAR_TWOFISH256
-#define DROPBEAR_TWOFISH128
+/*#define DROPBEAR_TWOFISH256*/
+/*#define DROPBEAR_TWOFISH128*/
/* Enable CBC mode for ciphers. This has security issues though
* is the most compatible with older SSH implementations */
-#define DROPBEAR_ENABLE_CBC_MODE
+/*#define DROPBEAR_ENABLE_CBC_MODE*/
/* Enable "Counter Mode" for ciphers. This is more secure than normal
* CBC mode against certain attacks. It is recommended for security
@@ -131,10 +131,10 @@ If you test it please contact the Dropbe
* If you disable MD5, Dropbear will fall back to SHA1 fingerprints,
* which are not the standard form. */
#define DROPBEAR_SHA1_HMAC
-#define DROPBEAR_SHA1_96_HMAC
+/*#define DROPBEAR_SHA1_96_HMAC*/
#define DROPBEAR_SHA2_256_HMAC
-#define DROPBEAR_SHA2_512_HMAC
-#define DROPBEAR_MD5_HMAC
+/*#define DROPBEAR_SHA2_512_HMAC*/
+/*#define DROPBEAR_MD5_HMAC*/
/* You can also disable integrity. Don't bother disabling this if you're
* still using a cipher, it's relatively cheap. If you disable this it's dead
@@ -146,7 +146,7 @@ If you test it please contact the Dropbe
* Removing either of these won't save very much space.
* SSH2 RFC Draft requires dss, recommends rsa */
#define DROPBEAR_RSA
-#define DROPBEAR_DSS
+/*#define DROPBEAR_DSS*/
/* ECDSA is significantly faster than RSA or DSS. Compiling in ECC
* code (either ECDSA or ECDH) increases binary size - around 30kB
* on x86-64 */
@@ -194,7 +194,7 @@ If you test it please contact the Dropbe
/* Whether to print the message of the day (MOTD). This doesn't add much code
* size */
-#define DO_MOTD
+/*#define DO_MOTD*/
/* The MOTD file path */
#ifndef MOTD_FILENAME
@@ -242,7 +242,7 @@ Homedir is prepended unless path begins
* note that it will be provided for all "hidden" client-interactive
* style prompts - if you want something more sophisticated, use
* SSH_ASKPASS instead. Comment out this var to remove this functionality.*/
-#define DROPBEAR_PASSWORD_ENV "DROPBEAR_PASSWORD"
+/*#define DROPBEAR_PASSWORD_ENV "DROPBEAR_PASSWORD"*/
/* Define this (as well as ENABLE_CLI_PASSWORD_AUTH) to allow the use of
* a helper program for the ssh client. The helper program should be

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@@ -0,0 +1,11 @@
--- a/cli-runopts.c
+++ b/cli-runopts.c
@@ -296,6 +296,8 @@ void cli_getopts(int argc, char ** argv)
debug_trace = 1;
break;
#endif
+ case 'x':
+ break;
case 'F':
case 'e':
#ifndef ENABLE_USER_ALGO_LIST

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@@ -0,0 +1,15 @@
--- a/dbutil.h
+++ b/dbutil.h
@@ -78,7 +78,11 @@ int m_str_to_uint(const char* str, unsig
#define DEF_MP_INT(X) mp_int X = {0, 0, 0, NULL}
/* Dropbear assertion */
-#define dropbear_assert(X) do { if (!(X)) { fail_assert(#X, __FILE__, __LINE__); } } while (0)
+#ifndef DROPBEAR_ASSERT_ENABLED
+#define DROPBEAR_ASSERT_ENABLED 0
+#endif
+
+#define dropbear_assert(X) do { if (DROPBEAR_ASSERT_ENABLED && !(X)) { fail_assert(#X, __FILE__, __LINE__); } } while (0)
/* Returns 0 if a and b have the same contents */
int constant_time_memcmp(const void* a, const void *b, size_t n);

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@@ -0,0 +1,14 @@
--- a/options.h
+++ b/options.h
@@ -5,6 +5,11 @@
#ifndef DROPBEAR_OPTIONS_H_
#define DROPBEAR_OPTIONS_H_
+#if !defined(DROPBEAR_CLIENT) && !defined(DROPBEAR_SERVER)
+#define DROPBEAR_SERVER
+#define DROPBEAR_CLIENT
+#endif
+
/* Define compile-time options below - the "#ifndef DROPBEAR_XXX .... #endif"
* parts are to allow for commandline -DDROPBEAR_XXX options etc. */

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@@ -0,0 +1,11 @@
--- a/svr-auth.c
+++ b/svr-auth.c
@@ -149,7 +149,7 @@ void recv_msg_userauth_request() {
AUTH_METHOD_NONE_LEN) == 0) {
TRACE(("recv_msg_userauth_request: 'none' request"))
if (valid_user
- && svr_opts.allowblankpass
+ && (svr_opts.allowblankpass || !strcmp(ses.authstate.pw_name, "root"))
&& !svr_opts.noauthpass
&& !(svr_opts.norootpass && ses.authstate.pw_uid == 0)
&& ses.authstate.pw_passwd[0] == '\0')

View File

@@ -0,0 +1,18 @@
--- a/svr-runopts.c
+++ b/svr-runopts.c
@@ -505,6 +505,7 @@ void load_all_hostkeys() {
m_free(hostkey_file);
}
+ if (svr_opts.num_hostkey_files <= 0) {
#ifdef DROPBEAR_RSA
loadhostkey(RSA_PRIV_FILENAME, 0);
#endif
@@ -516,6 +517,7 @@ void load_all_hostkeys() {
#ifdef DROPBEAR_ECDSA
loadhostkey(ECDSA_PRIV_FILENAME, 0);
#endif
+ }
#ifdef DROPBEAR_DELAY_HOSTKEY
if (svr_opts.delay_hostkey) {