FTP: when EPSV gets a 229 but fails to connect, retry with PASV

This is a regression as this logic used to work. It isn't clear when it broke, but I'm assuming in 7.28.0 when we went all-multi internally. This likely never worked with the multi interface. As the failed connection is detected once the multi state has reached DO_MORE, the Curl_do_more() function was now expanded somewhat so that the ftp_do_more() function can request to go "back" to the previous state when it makes another attempt - using PASV. Added test case 1233 to verify this fix. It has the little issue that it assumes no service is listening/accepting connections on port 1... Reported-by: byte_bucket in the #curl IRC channel
2024-12-21 15:48:49 -05:00 · 2013-08-05 23:49:53 +02:00 · 2013-08-05 23:49:53 +02:00 · 7cc00d9a83
commit 7cc00d9a83
parent 230e16dc03
7 changed files with 101 additions and 39 deletions
--- a/lib/ftp.c
+++ b/lib/ftp.c
@ -136,7 +136,7 @@ static CURLcode ftp_done(struct connectdata *conn,
                         CURLcode, bool premature);
 static CURLcode ftp_connect(struct connectdata *conn, bool *done);
 static CURLcode ftp_disconnect(struct connectdata *conn, bool dead_connection);
-static CURLcode ftp_do_more(struct connectdata *conn, bool *completed);
+static CURLcode ftp_do_more(struct connectdata *conn, int *completed);
 static CURLcode ftp_multi_statemach(struct connectdata *conn, bool *done);
 static int ftp_getsock(struct connectdata *conn, curl_socket_t *socks,
                       int numsocks);
@ -1799,15 +1799,15 @@ static CURLcode ftp_state_quote(struct connectdata *conn,
 static CURLcode ftp_epsv_disable(struct connectdata *conn)
 {
  CURLcode result = CURLE_OK;
-  infof(conn->data, "got positive EPSV response, but can't connect. "
-        "Disabling EPSV\n");
+  infof(conn->data, "Failed EPSV attempt. Disabling EPSV\n");
  /* disable it for next transfer */
  conn->bits.ftp_use_epsv = FALSE;
  conn->data->state.errorbuf = FALSE; /* allow error message to get
                                         rewritten */
  PPSENDF(&conn->proto.ftpc.pp, "%s", "PASV");
  conn->proto.ftpc.count1++;
-  /* remain in the FTP_PASV state */
+  /* remain in/go to the FTP_PASV state */
+  state(conn, FTP_PASV);
  return result;
 }

@ -1936,15 +1936,7 @@ static CURLcode ftp_state_pasv_resp(struct connectdata *conn,
  }
  else if(ftpc->count1 == 0) {
    /* EPSV failed, move on to PASV */
-
-    /* disable it for next transfer */
-    conn->bits.ftp_use_epsv = FALSE;
-    infof(data, "disabling EPSV usage\n");
-
-    PPSENDF(&ftpc->pp, "%s", "PASV");
-    ftpc->count1++;
-    /* remain in the FTP_PASV state */
-    return result;
+    return ftp_epsv_disable(conn);
  }
  else {
    failf(data, "Bad PASV/EPSV response: %03d", ftpcode);
@ -2021,14 +2013,17 @@ static CURLcode ftp_state_pasv_resp(struct connectdata *conn,
  case CURLPROXY_SOCKS5_HOSTNAME:
    result = Curl_SOCKS5(conn->proxyuser, conn->proxypasswd, newhost, newport,
                         SECONDARYSOCKET, conn);
+    connected = TRUE;
    break;
  case CURLPROXY_SOCKS4:
    result = Curl_SOCKS4(conn->proxyuser, newhost, newport,
                         SECONDARYSOCKET, conn, FALSE);
+    connected = TRUE;
    break;
  case CURLPROXY_SOCKS4A:
    result = Curl_SOCKS4(conn->proxyuser, newhost, newport,
                         SECONDARYSOCKET, conn, TRUE);
+    connected = TRUE;
    break;
  case CURLPROXY_HTTP:
  case CURLPROXY_HTTP_1_0:
@ -2080,8 +2075,7 @@ static CURLcode ftp_state_pasv_resp(struct connectdata *conn,
    }
  }

-  conn->bits.tcpconnect[SECONDARYSOCKET] = TRUE;
-
+  conn->bits.tcpconnect[SECONDARYSOCKET] = connected;
  conn->bits.do_more = TRUE;
  state(conn, FTP_STOP); /* this phase is completed */

@ -3677,20 +3671,23 @@ static CURLcode ftp_range(struct connectdata *conn)
 *
 * This function shall be called when the second FTP (data) connection is
 * connected.
+ *
+ * 'complete' can return 0 for incomplete, 1 for done and -1 for go back
+ * (which basically is only for when PASV is being sent to retry a failed
+ * EPSV).
 */

-static CURLcode ftp_do_more(struct connectdata *conn, bool *complete)
+static CURLcode ftp_do_more(struct connectdata *conn, int *completep)
 {
  struct SessionHandle *data=conn->data;
  struct ftp_conn *ftpc = &conn->proto.ftpc;
  CURLcode result = CURLE_OK;
  bool connected = FALSE;
+  bool complete = FALSE;

  /* the ftp struct is inited in ftp_connect() */
  struct FTP *ftp = data->state.proto.ftp;

-  *complete = FALSE;
-
  /* if the second connection isn't done yet, wait for it */
  if(!conn->bits.tcpconnect[SECONDARYSOCKET]) {
    if(conn->tunnel_state[SECONDARYSOCKET] == TUNNEL_CONNECT) {
@ -3707,14 +3704,22 @@ static CURLcode ftp_do_more(struct connectdata *conn, bool *complete)
    if(connected) {
      DEBUGF(infof(data, "DO-MORE connected phase starts\n"));
    }
-    else
+    else {
+      if(result && (ftpc->count1 == 0)) {
+        *completep = -1; /* go back to DOING please */
+        /* this is a EPSV connect failing, try PASV instead */
+        return ftp_epsv_disable(conn);
+      }
      return result;
+    }
  }

  if(ftpc->state) {
    /* already in a state so skip the intial commands.
       They are only done to kickstart the do_more state */
-    result = ftp_multi_statemach(conn, complete);
+    result = ftp_multi_statemach(conn, &complete);
+
+    *completep = (int)complete;

    /* if we got an error or if we don't wait for a data connection return
       immediately */
@ -3725,7 +3730,7 @@ static CURLcode ftp_do_more(struct connectdata *conn, bool *complete)
      /* if we reach the end of the FTP state machine here, *complete will be
         TRUE but so is ftpc->wait_data_conn, which says we need to wait for
         the data connection and therefore we're not actually complete */
-      *complete = FALSE;
+      *completep = 0;
  }

  if(ftp->transfer <= FTPTRANSFER_INFO) {
@ -3749,8 +3754,8 @@ static CURLcode ftp_do_more(struct connectdata *conn, bool *complete)
        if(result)
          return result;

-        *complete = TRUE; /* this state is now complete when the server has
-                             connected back to us */
+        *completep = 1; /* this state is now complete when the server has
+                           connected back to us */
      }
    }
    else if(data->set.upload) {
@ -3758,7 +3763,8 @@ static CURLcode ftp_do_more(struct connectdata *conn, bool *complete)
      if(result)
        return result;

-      result = ftp_multi_statemach(conn, complete);
+      result = ftp_multi_statemach(conn, &complete);
+      *completep = (int)complete;
    }
    else {
      /* download */
@ -3786,7 +3792,8 @@ static CURLcode ftp_do_more(struct connectdata *conn, bool *complete)
          return result;
      }

-      result = ftp_multi_statemach(conn, complete);
+      result = ftp_multi_statemach(conn, &complete);
+      *completep = (int)complete;
    }
    return result;
  }
@ -3798,7 +3805,7 @@ static CURLcode ftp_do_more(struct connectdata *conn, bool *complete)

  if(!ftpc->wait_data_conn) {
    /* no waiting for the data connection so this is now complete */
-    *complete = TRUE;
+    *completep = 1;
    DEBUGF(infof(data, "DO-MORE phase ends with %d\n", (int)result));
  }

@ -3841,7 +3848,9 @@ CURLcode ftp_perform(struct connectdata *conn,
  /* run the state-machine */
  result = ftp_multi_statemach(conn, dophase_done);

-  *connected = conn->bits.tcpconnect[FIRSTSOCKET];
+  *connected = conn->bits.tcpconnect[SECONDARYSOCKET];
+
+  infof(conn->data, "ftp_perform ends with SECONDARY: %d\n", *connected);

  if(*dophase_done)
    DEBUGF(infof(conn->data, "DO phase is complete1\n"));
@ -4469,7 +4478,7 @@ static CURLcode ftp_dophase_done(struct connectdata *conn,
  struct ftp_conn *ftpc = &conn->proto.ftpc;

  if(connected) {
-    bool completed;
+    int completed;
    CURLcode result = ftp_do_more(conn, &completed);

    if(result) {
--- a/lib/multi.c
+++ b/lib/multi.c
@ -929,6 +929,7 @@ static CURLMcode multi_runsingle(struct Curl_multi *multi,
  struct SingleRequest *k;
  struct SessionHandle *data;
  long timeout_ms;
+  int control;

  if(!GOOD_EASY_HANDLE(easy))
    return CURLM_BAD_EASY_HANDLE;
@ -1359,13 +1360,17 @@ static CURLMcode multi_runsingle(struct Curl_multi *multi,
      /*
       * When we are connected, DO MORE and then go DO_DONE
       */
-      easy->result = Curl_do_more(easy->easy_conn, &dophase_done);
+      easy->result = Curl_do_more(easy->easy_conn, &control);

      /* No need to remove this handle from the send pipeline here since that
         is done in Curl_done() */
      if(CURLE_OK == easy->result) {
-        if(dophase_done) {
-          multistate(easy, CURLM_STATE_DO_DONE);
+        if(control) {
+          /* if positive, advance to DO_DONE
+             if negative, go back to DOING */
+          multistate(easy, control==1?
+                     CURLM_STATE_DO_DONE:
+                     CURLM_STATE_DOING);
          result = CURLM_CALL_MULTI_PERFORM;
        }
        else
--- a/lib/url.c
+++ b/lib/url.c
@ -5841,18 +5841,20 @@ CURLcode Curl_do(struct connectdata **connp, bool *done)
 *
 * TODO: A future libcurl should be able to work away this state.
 *
+ * 'complete' can return 0 for incomplete, 1 for done and -1 for go back to
+ * DOING state there's more work to do!
 */

-CURLcode Curl_do_more(struct connectdata *conn, bool *completed)
+CURLcode Curl_do_more(struct connectdata *conn, int *complete)
 {
  CURLcode result=CURLE_OK;

-  *completed = FALSE;
+  *complete = 0;

  if(conn->handler->do_more)
-    result = conn->handler->do_more(conn, completed);
+    result = conn->handler->do_more(conn, complete);

-  if(!result && *completed)
+  if(!result && (*complete == 1))
    /* do_complete must be called after the protocol-specific DO function */
    do_complete(conn);

--- a/lib/url.h
+++ b/lib/url.h
@ -7,7 +7,7 @@
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
- * Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
@ -37,7 +37,7 @@ CURLcode Curl_close(struct SessionHandle *data); /* opposite of curl_open() */
 CURLcode Curl_connect(struct SessionHandle *, struct connectdata **,
                      bool *async, bool *protocol_connect);
 CURLcode Curl_do(struct connectdata **, bool *done);
-CURLcode Curl_do_more(struct connectdata *, bool *completed);
+CURLcode Curl_do_more(struct connectdata *, int *completed);
 CURLcode Curl_done(struct connectdata **, CURLcode, bool premature);
 CURLcode Curl_disconnect(struct connectdata *, bool dead_connection);
 CURLcode Curl_protocol_connect(struct connectdata *conn, bool *done);
--- a/lib/urldata.h
+++ b/lib/urldata.h
@ -577,7 +577,7 @@ struct Curl_async {
 /* These function pointer types are here only to allow easier typecasting
   within the source when we need to cast between data pointers (such as NULL)
   and function pointers. */
-typedef CURLcode (*Curl_do_more_func)(struct connectdata *, bool *);
+typedef CURLcode (*Curl_do_more_func)(struct connectdata *, int *);
 typedef CURLcode (*Curl_done_func)(struct connectdata *, CURLcode, bool);


--- a/tests/data/Makefile.am
+++ b/tests/data/Makefile.am
@ -93,7 +93,7 @@ test1200 test1201 test1202 test1203 test1204 test1205 test1206 test1207 \
 test1208 test1209 test1210 test1211 test1212 test1213 test1214 test1215 \
 test1216 test1217 test1218 test1219 \
 test1220 test1221 test1222 test1223 test1224 test1225 test1226 test1227 \
-test1228 test1229 test1230 test1231 test1232 \
+test1228 test1229 test1230 test1231 test1232 test1233 \
 \
 test1300 test1301 test1302 test1303 test1304 test1305 test1306 test1307 \
 test1308 test1309 test1310 test1311 test1312 test1313 test1314 test1315 \
--- a/tests/data/test1233
+++ b/tests/data/test1233
@ -0,0 +1,46 @@
+<testcase>
+<info>
+<keywords>
+FTP
+</keywords>
+</info>
+
+# Server-side
+<reply>
+<servercmd>
+# Assuming there's nothing listening on port 1
+REPLY EPSV 229 Entering Passiv Mode (|||1|)
+</servercmd>
+<data>
+here are some bytes
+</data>
+</reply>
+
+# Client-side
+<client>
+<server>
+ftp
+</server>
+ <name>
+FTP failing to connect to EPSV port, switching to PASV
+ </name>
+ <command>
+ftp://%HOSTIP:%FTPPORT/1233
+</command>
+</client>
+
+# Verify data after the test has been "shot"
+<verify>
+<protocol>
+USER anonymous
+PASS ftp@example.com
+PWD
+EPSV
+PASV
+TYPE I
+SIZE 1233
+RETR 1233
+QUIT
+</protocol>
+</verify>
+</testcase>