From dad0fe12628867cc871c8f2e40e8c063bbc2a532 Mon Sep 17 00:00:00 2001
From: hno <>
Date: Sun, 4 Apr 2004 21:05:13 +0000
Subject: [PATCH] Bug #877: Squid doesn't follow telnet protocol on FTP control
 connections

Squid forgot to escape IAC characters (ascii code 255) in FTP requests,
causing problems to access files/directories using this character in their
name or to log in with this character in the login or password.
---
 src/cf.data.pre | 19 ++++++++++++++++++-
 src/ftp.cc      | 41 +++++++++++++++++++++++++++++++++++++++--
 src/structs.h   |  3 ++-
 3 files changed, 59 insertions(+), 4 deletions(-)

diff --git a/src/cf.data.pre b/src/cf.data.pre
index 5ebdc323c0..2e4709c4b0 100644
--- a/src/cf.data.pre
+++ b/src/cf.data.pre
@@ -1,6 +1,6 @@
 
 #
-# $Id: cf.data.pre,v 1.346 2004/04/04 13:57:30 hno Exp $
+# $Id: cf.data.pre,v 1.347 2004/04/04 15:05:13 hno Exp $
 #
 #
 # SQUID Web Proxy Cache          http://www.squid-cache.org/
@@ -1443,6 +1443,23 @@ DOC_START
 	Squid to perform these checks then turn this directive off.
 DOC_END
 
+NAME: ftp_telnet_protocol
+TYPE: onoff
+DEFAULT: on
+LOC: Config.Ftp.telnet
+DOC_START
+The FTP protocol is officially defined to use the telnet protocol
+as transport channel for the control connection. However, many
+implemenations are broken and does not respect this aspect of
+the FTP protocol.
+
+If you have trouble accessing files with ASCII code 255 in the
+path or similar problems involving this ASCII code then you can
+try setting this directive to off. If that helps report to the
+operator of the FTP server in question that their FTP server
+is broken and does not follow the FTP standard.
+DOC_END
+
 NAME: cache_dns_program
 TYPE: string
 IFDEF: USE_DNSSERVERS
diff --git a/src/ftp.cc b/src/ftp.cc
index 8c8e823332..8b1c8d63ff 100644
--- a/src/ftp.cc
+++ b/src/ftp.cc
@@ -1,6 +1,6 @@
 
 /*
- * $Id: ftp.cc,v 1.356 2004/04/04 14:47:06 hno Exp $
+ * $Id: ftp.cc,v 1.357 2004/04/04 15:05:13 hno Exp $
  *
  * DEBUG: section 9     File Transfer Protocol (FTP)
  * AUTHOR: Harvest Derived
@@ -1429,18 +1429,55 @@ ftpStart(FwdState * fwd)
 
 /* ====================================================================== */
 
+static char *
+escapeIAC(const char *buf)
+{
+    int n;
+    char *ret;
+    unsigned const char *p;
+    unsigned char *r;
+
+    for (p = (unsigned const char *)buf, n = 1; *p; n++, p++)
+        if (*p == 255)
+            n++;
+
+    ret = (char *)xmalloc(n);
+
+    for (p = (unsigned const char *)buf, r=(unsigned char *)ret; *p; p++) {
+        *r++ = *p;
+
+        if (*p == 255)
+            *r++ = 255;
+    }
+
+    *r++ = '\0';
+    assert((r - (unsigned char *)ret) == n );
+    return ret;
+}
+
 static void
 ftpWriteCommand(const char *buf, FtpStateData * ftpState)
 {
+    char *ebuf;
     debug(9, 5) ("ftpWriteCommand: %s\n", buf);
+
+    if (Config.Ftp.telnet)
+        ebuf = escapeIAC(buf);
+    else
+        ebuf = xstrdup(buf);
+
     safe_free(ftpState->ctrl.last_command);
+
     safe_free(ftpState->ctrl.last_reply);
-    ftpState->ctrl.last_command = xstrdup(buf);
+
+    ftpState->ctrl.last_command = ebuf;
+
     comm_write(ftpState->ctrl.fd,
                ftpState->ctrl.last_command,
                strlen(ftpState->ctrl.last_command),
                ftpWriteCommandCallback,
                ftpState);
+
     ftpScheduleReadControlReply(ftpState, 0);
 }
 
diff --git a/src/structs.h b/src/structs.h
index 69cd4ee34a..51e576f0fb 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -1,6 +1,6 @@
 
 /*
- * $Id: structs.h,v 1.485 2004/04/03 14:07:39 hno Exp $
+ * $Id: structs.h,v 1.486 2004/04/04 15:05:13 hno Exp $
  *
  *
  * SQUID Web Proxy Cache          http://www.squid-cache.org/
@@ -604,6 +604,7 @@ struct _SquidConfig
         char *anon_user;
         int passive;
         int sanitycheck;
+        int telnet;
     }
 
     Ftp;
-- 
2.47.2