ftpd: conditional support for broken clients

Signed-off-by: Stefan Seyfried <stefan.seyfried@googlemail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 23 insertions, 0 deletions

diff --git a/networking/Config.in b/networking/Config.in
index 80834c6d4..788e128ea 100644
--- a/networking/Config.in
+++ b/networking/Config.in
@@ -117,6 +117,17 @@ config FEATURE_FTP_WRITE
         help
           Enable all kinds of FTP upload commands (-w option)
 
+config FEATURE_FTPD_ACCEPT_BROKEN_LIST
+        bool "Enable workaround for RFC-violating clients"
+        default y
+        depends on FTPD
+        help
+          Some ftp-clients (among them KDE's Konqueror) issue illegal
+          "LIST -la" requests. This option works around those problems.
+          It might prevent you from listing files starting with "-" and
+          it increases the code size by ~40 bytes.
+          Most other ftp servers seem to behave similar to this.
+
 config FTPGET
         bool "ftpget"
         default n
diff --git a/networking/ftpd.c b/networking/ftpd.c
index 4e9f65ca3..fdc6f5e45 100644
--- a/networking/ftpd.c
+++ b/networking/ftpd.c
@@ -632,6 +632,18 @@ popen_ls(const char *opt)
         argv[3] = G.ftp_arg;
         argv[4] = NULL;
 
+        /* Improve compatibility with non-RFC conforming FTP clients
+         * which send e.g. "LIST -l", "LIST -la".
+         * See https://bugs.kde.org/show_bug.cgi?id=195578 */
+        if (ENABLE_FEATURE_FTPD_ACCEPT_BROKEN_LIST
+         && G.ftp_arg && G.ftp_arg[0] == '-' && G.ftp_arg[1] == 'l'
+        ) {
+                const char *tmp = strchr(G.ftp_arg, ' ');
+                if (tmp) /* skip the space */
+                        tmp++;
+                argv[3] = tmp;
+        }
+
         xpiped_pair(outfd);
 
         /*fflush_all(); - so far we dont use stdio on output */