Allow configuring "allow blank password option" at runtime

Changes this from a compile-time switch to a command-line option.

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>

Upstream-Status: Pending

diff --git a/options.h b/options.h
index 00f6179..b8d0ccb 100644
--- a/options.h
+++ b/options.h
@@ -176,12 +176,6 @@ much traffic. */
 #define ENABLE_SVR_PUBKEY_OPTIONS
 #endif
 
-/* Define this to allow logging in to accounts that have no password specified.
- * Public key logins are allowed for blank-password accounts regardless of this
- * setting.  PAM is not affected by this setting, it uses the normal pam.d
- * settings ('nullok' option) */
-/* #define ALLOW_BLANK_PASSWORD */
-
 #define ENABLE_CLI_PASSWORD_AUTH
 #define ENABLE_CLI_PUBKEY_AUTH
 #define ENABLE_CLI_INTERACT_AUTH
diff --git a/runopts.h b/runopts.h
index 83b5861..126585b 100644
--- a/runopts.h
+++ b/runopts.h
@@ -85,6 +85,7 @@ typedef struct svr_runopts {
 
 	int noauthpass;
 	int norootpass;
+	int allowblankpass;
 
 #ifdef ENABLE_SVR_REMOTETCPFWD
 	int noremotetcp;
diff --git a/svr-authpasswd.c b/svr-authpasswd.c
index 54b4889..d9b7928 100644
--- a/svr-authpasswd.c
+++ b/svr-authpasswd.c
@@ -29,6 +29,7 @@
 #include "buffer.h"
 #include "dbutil.h"
 #include "auth.h"
+#include "runopts.h"
 
 #ifdef ENABLE_SVR_PASSWORD_AUTH
 
@@ -78,16 +79,17 @@ void svr_auth_password() {
 
 	/* check for empty password */
 	if (passwdcrypt[0] == '\0') {
-#ifdef ALLOW_BLANK_PASSWORD
-		if (passwordlen == 0) {
-			success_blank = 1;
+		if (svr_opts.allowblankpass) {
+			if (passwordlen == 0) {
+				success_blank = 1;
+			}
+		}
+		else {
+			dropbear_log(LOG_WARNING, "User '%s' has blank password, rejected",
+					ses.authstate.pw_name);
+			send_msg_userauth_failure(0, 1);
+			return;
 		}
-#else
-		dropbear_log(LOG_WARNING, "User '%s' has blank password, rejected",
-				ses.authstate.pw_name);
-		send_msg_userauth_failure(0, 1);
-		return;
-#endif
 	}
 
 	if (success_blank || strcmp(testcrypt, passwdcrypt) == 0) {
diff --git a/svr-runopts.c b/svr-runopts.c
index c6e3508..b39ffb2 100644
--- a/svr-runopts.c
+++ b/svr-runopts.c
@@ -63,6 +63,7 @@ static void printhelp(const char * progname) {
 #if defined(ENABLE_SVR_PASSWORD_AUTH) || defined(ENABLE_SVR_PAM_AUTH)
 					"-s		Disable password logins\n"
 					"-g		Disable password logins for root\n"
+					"-B		Allow blank password logins\n"
 #endif
 #ifdef ENABLE_SVR_LOCALTCPFWD
 					"-j		Disable local port forwarding\n"
@@ -115,6 +116,7 @@ void svr_getopts(int argc, char ** argv) {
 	svr_opts.norootlogin = 0;
 	svr_opts.noauthpass = 0;
 	svr_opts.norootpass = 0;
+	svr_opts.allowblankpass = 0;
 	svr_opts.inetdmode = 0;
 	svr_opts.portcount = 0;
 	svr_opts.hostkey = NULL;
@@ -234,6 +236,9 @@ void svr_getopts(int argc, char ** argv) {
 				case 'g':
 					svr_opts.norootpass = 1;
 					break;
+				case 'B':
+					svr_opts.allowblankpass = 1;
+					break;
 #endif
 				case 'h':
 					printhelp(argv[0]);