From feac9b607dc68ea63992a46b3b8361f00f663cdc Mon Sep 17 00:00:00 2001
From: Morten Kvistgaard
Date: Tue, 5 Aug 2014 21:57:18 +0200
Subject: ftpd: add optional support for authentication

function                                             old     new   delta
cmdio_get_cmd_and_arg                                  -     237    +237
get_passwd                                             -      97     +97
check_password                                         -      82     +82
ftpd_main                                           2297    2178    -119
ask_and_check_password_extended                      206      84    -122
------------------------------------------------------------------------------
(add/remove: 3/0 grow/shrink: 0/2 up/down: 416/-241)          Total: 175 bytes

Signed-off-by: Morten Kvistgaard <MK@pch-engineering.dk>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
---
 networking/Config.src |  7 +++++++
 networking/ftpd.c     | 47 ++++++++++++++++++++++++-----------------------
 2 files changed, 31 insertions(+), 23 deletions(-)

(limited to 'networking')

diff --git a/networking/Config.src b/networking/Config.src
index fbad7ec..e566469 100644
--- a/networking/Config.src
+++ b/networking/Config.src
@@ -134,6 +134,13 @@ config FEATURE_FTPD_ACCEPT_BROKEN_LIST
 	  it increases the code size by ~40 bytes.
 	  Most other ftp servers seem to behave similar to this.
 
+config FEATURE_FTP_AUTHENTICATION
+	bool "Enable authentication"
+	default y
+	depends on FTPD
+	help
+	  Enable basic system login as seen in telnet etc.
+
 config FTPGET
 	bool "ftpget"
 	default y
diff --git a/networking/ftpd.c b/networking/ftpd.c
index 2d2a3a4..9fcc3e9 100644
--- a/networking/ftpd.c
+++ b/networking/ftpd.c
@@ -1172,18 +1172,6 @@ int ftpd_main(int argc UNUSED_PARAM, char **argv)
 	if (logmode)
 		applet_name = xasprintf("%s[%u]", applet_name, (int)getpid());
 
-#if !BB_MMU
-	G.root_fd = -1;
-#endif
-	argv += optind;
-	if (argv[0]) {
-#if !BB_MMU
-		G.root_fd = xopen("/", O_RDONLY | O_DIRECTORY);
-		close_on_exec_on(G.root_fd);
-#endif
-		xchroot(argv[0]);
-	}
-
 	//umask(077); - admin can set umask before starting us
 
 	/* Signals. We'll always take -EPIPE rather than a rude signal, thanks */
@@ -1199,23 +1187,22 @@ int ftpd_main(int argc UNUSED_PARAM, char **argv)
 	WRITE_OK(FTP_GREET);
 	signal(SIGALRM, timeout_handler);
 
-#ifdef IF_WE_WANT_TO_REQUIRE_LOGIN
+#if ENABLE_FEATURE_FTP_AUTHENTICATION
 	{
-		smallint user_was_specified = 0;
+		struct passwd *pw = NULL;
+
 		while (1) {
 			uint32_t cmdval = cmdio_get_cmd_and_arg();
 
 			if (cmdval == const_USER) {
-				if (G.ftp_arg == NULL || strcasecmp(G.ftp_arg, "anonymous") != 0)
-					cmdio_write_raw(STR(FTP_LOGINERR)" Server is anonymous only\r\n");
-				else {
-					user_was_specified = 1;
-					cmdio_write_raw(STR(FTP_GIVEPWORD)" Please specify the password\r\n");
-				}
+				pw = getpwnam(G.ftp_arg);
+				cmdio_write_raw(STR(FTP_GIVEPWORD)" Please specify password\r\n");
 			} else if (cmdval == const_PASS) {
-				if (user_was_specified)
-					break;
-				cmdio_write_raw(STR(FTP_NEEDUSER)" Login with USER\r\n");
+				if (check_password(pw, G.ftp_arg) > 0) {
+					break;	/* login success */
+				}
+				cmdio_write_raw(STR(FTP_LOGINERR)" Login failed\r\n");
+				pw = NULL;
 			} else if (cmdval == const_QUIT) {
 				WRITE_OK(FTP_GOODBYE);
 				return 0;
@@ -1223,10 +1210,24 @@ int ftpd_main(int argc UNUSED_PARAM, char **argv)
 				cmdio_write_raw(STR(FTP_LOGINERR)" Login with USER and PASS\r\n");
 			}
 		}
+		change_identity(pw);
 	}
 	WRITE_OK(FTP_LOGINOK);
 #endif
 
+	/* Do this after auth, else /etc/passwd is not accessible */
+#if !BB_MMU
+	G.root_fd = -1;
+#endif
+	argv += optind;
+	if (argv[0]) {
+#if !BB_MMU
+		G.root_fd = xopen("/", O_RDONLY | O_DIRECTORY);
+		close_on_exec_on(G.root_fd);
+#endif
+		xchroot(argv[0]);
+	}
+
 	/* RFC-959 Section 5.1
 	 * The following commands and options MUST be supported by every
 	 * server-FTP and user-FTP, except in cases where the underlying
-- 
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