libssh: do not let libssh create socket

By default, libssh creates a new socket, instead of using the socket
created by curl for SSH connections.

Pass the socket created by curl to libssh using ssh_options_set() with
SSH_OPTIONS_FD directly after ssh_new(). So libssh uses our socket
instead of creating a new one.

This approach is very similar to what is done in the libssh2 code, where
the socket created by curl is passed to libssh2 when
libssh2_session_startup() is called.

Fixes #3491
Closes #3495

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/ssh-libssh.c b/lib/ssh-libssh.c
index 2e920f0e9..333df03ef 100644
--- a/lib/ssh-libssh.c
+++ b/lib/ssh-libssh.c
@@ -556,6 +556,7 @@ static CURLcode myssh_statemach_act(struct connectdata *conn, bool *block)
   struct Curl_easy *data = conn->data;
   struct SSHPROTO *protop = data->req.protop;
   struct ssh_conn *sshc = &conn->proto.sshc;
+  curl_socket_t sock = conn->sock[FIRSTSOCKET];
   int rc = SSH_NO_ERROR, err;
   char *new_readdir_line;
   int seekerr = CURL_SEEKFUNC_OK;
@@ -799,7 +800,7 @@ static CURLcode myssh_statemach_act(struct connectdata *conn, bool *block)
 
       Curl_pgrsTime(conn->data, TIMER_APPCONNECT);      /* SSH is connected */
 
-      conn->sockfd = ssh_get_fd(sshc->ssh_session);
+      conn->sockfd = sock;
       conn->writesockfd = CURL_SOCKET_BAD;
 
       if(conn->handler->protocol == CURLPROTO_SFTP) {
@@ -2052,6 +2053,7 @@ static CURLcode myssh_connect(struct connectdata *conn, bool *done)
 {
   struct ssh_conn *ssh;
   CURLcode result;
+  curl_socket_t sock = conn->sock[FIRSTSOCKET];
   struct Curl_easy *data = conn->data;
   int rc;
 
@@ -2080,6 +2082,8 @@ static CURLcode myssh_connect(struct connectdata *conn, bool *done)
     return CURLE_FAILED_INIT;
   }
 
+  ssh_options_set(ssh->ssh_session, SSH_OPTIONS_FD, &sock);
+
   if(conn->user) {
     infof(data, "User: %s\n", conn->user);
     ssh_options_set(ssh->ssh_session, SSH_OPTIONS_USER, conn->user);