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mc/src/vfs/sftpfs/connection.c
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| /* Virtual File System: SFTP file system. | |
| The internal functions: connections | |
| Copyright (C) 2011-2021 | |
| Free Software Foundation, Inc. | |
| Written by: | |
| Ilia Maslakov <il.smind@gmail.com>, 2011 | |
| Slava Zanko <slavazanko@gmail.com>, 2011, 2012, 2013 | |
| This file is part of the Midnight Commander. | |
| The Midnight Commander is free software: you can redistribute it | |
| and/or modify it under the terms of the GNU General Public License as | |
| published by the Free Software Foundation, either version 3 of the License, | |
| or (at your option) any later version. | |
| The Midnight Commander is distributed in the hope that it will be useful, | |
| but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| GNU General Public License for more details. | |
| You should have received a copy of the GNU General Public License | |
| along with this program. If not, see <http://www.gnu.org/licenses/>. | |
| */ | |
| #include <config.h> | |
| #include <errno.h> | |
| #include <netdb.h> /* struct hostent */ | |
| #include <sys/socket.h> /* AF_INET */ | |
| #include <netinet/in.h> /* struct in_addr */ | |
| #ifdef HAVE_ARPA_INET_H | |
| #include <arpa/inet.h> | |
| #endif | |
| #include <libssh2.h> | |
| #include <libssh2_sftp.h> | |
| #include "lib/global.h" | |
| #include "lib/util.h" | |
| #include "lib/tty/tty.h" /* tty_enable_interrupt_key () */ | |
| #include "lib/vfs/utilvfs.h" | |
| #include "internal.h" | |
| /*** global variables ****************************************************************************/ | |
| /*** file scope macro definitions ****************************************************************/ | |
| /*** file scope type declarations ****************************************************************/ | |
| /*** file scope variables ************************************************************************/ | |
| static const char *kbi_passwd = NULL; | |
| static const struct vfs_s_super *kbi_super = NULL; | |
| /* --------------------------------------------------------------------------------------------- */ | |
| /*** file scope functions ************************************************************************/ | |
| /* --------------------------------------------------------------------------------------------- */ | |
| /** | |
| * Create socket to host. | |
| * | |
| * @param super connection data | |
| * @param mcerror pointer to the error handler | |
| * @return socket descriptor number, -1 if any error was occurred | |
| */ | |
| static int | |
| sftpfs_open_socket (struct vfs_s_super *super, GError ** mcerror) | |
| { | |
| struct addrinfo hints, *res = NULL, *curr_res; | |
| int my_socket = 0; | |
| char port[BUF_TINY]; | |
| int e; | |
| mc_return_val_if_error (mcerror, LIBSSH2_INVALID_SOCKET); | |
| if (super->path_element->host == NULL || *super->path_element->host == '\0') | |
| { | |
| mc_propagate_error (mcerror, 0, "%s", _("sftp: Invalid host name.")); | |
| return LIBSSH2_INVALID_SOCKET; | |
| } | |
| sprintf (port, "%hu", (unsigned short) super->path_element->port); | |
| tty_enable_interrupt_key (); /* clear the interrupt flag */ | |
| memset (&hints, 0, sizeof (hints)); | |
| hints.ai_family = AF_UNSPEC; | |
| hints.ai_socktype = SOCK_STREAM; | |
| #ifdef AI_ADDRCONFIG | |
| /* By default, only look up addresses using address types for | |
| * which a local interface is configured (i.e. no IPv6 if no IPv6 | |
| * interfaces, likewise for IPv4 (see RFC 3493 for details). */ | |
| hints.ai_flags = AI_ADDRCONFIG; | |
| #endif | |
| e = getaddrinfo (super->path_element->host, port, &hints, &res); | |
| #ifdef AI_ADDRCONFIG | |
| if (e == EAI_BADFLAGS) | |
| { | |
| /* Retry with no flags if AI_ADDRCONFIG was rejected. */ | |
| hints.ai_flags = 0; | |
| e = getaddrinfo (super->path_element->host, port, &hints, &res); | |
| } | |
| #endif | |
| if (e != 0) | |
| { | |
| mc_propagate_error (mcerror, e, _("sftp: %s"), gai_strerror (e)); | |
| my_socket = LIBSSH2_INVALID_SOCKET; | |
| goto ret; | |
| } | |
| for (curr_res = res; curr_res != NULL; curr_res = curr_res->ai_next) | |
| { | |
| int save_errno; | |
| my_socket = socket (curr_res->ai_family, curr_res->ai_socktype, curr_res->ai_protocol); | |
| if (my_socket < 0) | |
| { | |
| if (curr_res->ai_next != NULL) | |
| continue; | |
| vfs_print_message (_("sftp: %s"), unix_error_string (errno)); | |
| my_socket = LIBSSH2_INVALID_SOCKET; | |
| goto ret; | |
| } | |
| vfs_print_message (_("sftp: making connection to %s"), super->path_element->host); | |
| if (connect (my_socket, curr_res->ai_addr, curr_res->ai_addrlen) >= 0) | |
| break; | |
| save_errno = errno; | |
| close (my_socket); | |
| if (save_errno == EINTR && tty_got_interrupt ()) | |
| mc_propagate_error (mcerror, 0, "%s", _("sftp: connection interrupted by user")); | |
| else if (res->ai_next == NULL) | |
| mc_propagate_error (mcerror, save_errno, _("sftp: connection to server failed: %s"), | |
| unix_error_string (save_errno)); | |
| else | |
| continue; | |
| my_socket = LIBSSH2_INVALID_SOCKET; | |
| break; | |
| } | |
| ret: | |
| if (res != NULL) | |
| freeaddrinfo (res); | |
| tty_disable_interrupt_key (); | |
| return my_socket; | |
| } | |
| /* --------------------------------------------------------------------------------------------- */ | |
| /** | |
| * Recognize authenticaion types supported by remote side and filling internal 'super' structure by | |
| * proper enum's values. | |
| * | |
| * @param super connection data | |
| * @return TRUE if some of authentication methods is available, FALSE otherwise | |
| */ | |
| static gboolean | |
| sftpfs_recognize_auth_types (struct vfs_s_super *super) | |
| { | |
| char *userauthlist; | |
| sftpfs_super_t *sftpfs_super = SFTP_SUPER (super); | |
| /* check what authentication methods are available */ | |
| /* userauthlist is internally managed by libssh2 and freed by libssh2_session_free() */ | |
| userauthlist = libssh2_userauth_list (sftpfs_super->session, super->path_element->user, | |
| strlen (super->path_element->user)); | |
| if (userauthlist == NULL) | |
| return FALSE; | |
| if ((strstr (userauthlist, "password") != NULL | |
| || strstr (userauthlist, "keyboard-interactive") != NULL) | |
| && (sftpfs_super->config_auth_type & PASSWORD) != 0) | |
| sftpfs_super->auth_type |= PASSWORD; | |
| if (strstr (userauthlist, "publickey") != NULL | |
| && (sftpfs_super->config_auth_type & PUBKEY) != 0) | |
| sftpfs_super->auth_type |= PUBKEY; | |
| if ((sftpfs_super->config_auth_type & AGENT) != 0) | |
| sftpfs_super->auth_type |= AGENT; | |
| return TRUE; | |
| } | |
| /* --------------------------------------------------------------------------------------------- */ | |
| /** | |
| * Open connection to host using SSH-agent helper. | |
| * | |
| * @param super connection data | |
| * @param mcerror pointer to the error handler | |
| * @return TRUE if connection was successfully opened, FALSE otherwise | |
| */ | |
| static gboolean | |
| sftpfs_open_connection_ssh_agent (struct vfs_s_super *super, GError ** mcerror) | |
| { | |
| sftpfs_super_t *sftpfs_super = SFTP_SUPER (super); | |
| struct libssh2_agent_publickey *identity, *prev_identity = NULL; | |
| int rc; | |
| mc_return_val_if_error (mcerror, FALSE); | |
| sftpfs_super->agent = NULL; | |
| if ((sftpfs_super->auth_type & AGENT) == 0) | |
| return FALSE; | |
| /* Connect to the ssh-agent */ | |
| sftpfs_super->agent = libssh2_agent_init (sftpfs_super->session); | |
| if (sftpfs_super->agent == NULL) | |
| return FALSE; | |
| if (libssh2_agent_connect (sftpfs_super->agent) != 0) | |
| return FALSE; | |
| if (libssh2_agent_list_identities (sftpfs_super->agent) != 0) | |
| return FALSE; | |
| while (TRUE) | |
| { | |
| rc = libssh2_agent_get_identity (sftpfs_super->agent, &identity, prev_identity); | |
| if (rc == 1) | |
| break; | |
| if (rc < 0) | |
| return FALSE; | |
| if (libssh2_agent_userauth (sftpfs_super->agent, super->path_element->user, identity) == 0) | |
| break; | |
| prev_identity = identity; | |
| } | |
| return (rc == 0); | |
| } | |
| /* --------------------------------------------------------------------------------------------- */ | |
| /** | |
| * Open connection to host using SSH-keypair. | |
| * | |
| * @param super connection data | |
| * @param mcerror pointer to the error handler | |
| * @return TRUE if connection was successfully opened, FALSE otherwise | |
| */ | |
| static gboolean | |
| sftpfs_open_connection_ssh_key (struct vfs_s_super *super, GError ** mcerror) | |
| { | |
| sftpfs_super_t *sftpfs_super = SFTP_SUPER (super); | |
| char *p, *passwd; | |
| gboolean ret_value = FALSE; | |
| mc_return_val_if_error (mcerror, FALSE); | |
| if ((sftpfs_super->auth_type & PUBKEY) == 0) | |
| return FALSE; | |
| if (sftpfs_super->privkey == NULL) | |
| return FALSE; | |
| if (libssh2_userauth_publickey_fromfile (sftpfs_super->session, super->path_element->user, | |
| sftpfs_super->pubkey, sftpfs_super->privkey, | |
| super->path_element->password) == 0) | |
| return TRUE; | |
| p = g_strdup_printf (_("sftp: Enter passphrase for %s "), super->path_element->user); | |
| passwd = vfs_get_password (p); | |
| g_free (p); | |
| if (passwd == NULL) | |
| mc_propagate_error (mcerror, 0, "%s", _("sftp: Passphrase is empty.")); | |
| else | |
| { | |
| ret_value = (libssh2_userauth_publickey_fromfile (sftpfs_super->session, | |
| super->path_element->user, | |
| sftpfs_super->pubkey, | |
| sftpfs_super->privkey, passwd) == 0); | |
| g_free (passwd); | |
| } | |
| return ret_value; | |
| } | |
| /* --------------------------------------------------------------------------------------------- */ | |
| /** | |
| * Keyboard-interactive password helper for opening connection to host by | |
| * sftpfs_open_connection_ssh_password | |
| * | |
| * Uses global kbi_super (data with existing connection) and kbi_passwd (password) | |
| * | |
| * @param name username | |
| * @param name_len length of @name | |
| * @param instruction unused | |
| * @param instruction_len unused | |
| * @param num_prompts number of possible problems to process | |
| * @param prompts array of prompts to process | |
| * @param responses array of responses, one per prompt | |
| * @param abstract unused | |
| */ | |
| static | |
| LIBSSH2_USERAUTH_KBDINT_RESPONSE_FUNC (sftpfs_keyboard_interactive_helper) | |
| { | |
| int i; | |
| size_t len; | |
| (void) instruction; | |
| (void) instruction_len; | |
| (void) abstract; | |
| if (kbi_super == NULL || kbi_passwd == NULL) | |
| return; | |
| if (strncmp (name, kbi_super->path_element->user, name_len) != 0) | |
| return; | |
| /* assume these are password prompts */ | |
| len = strlen (kbi_passwd); | |
| for (i = 0; i < num_prompts; ++i) | |
| if (strncmp (prompts[i].text, "Password: ", prompts[i].length) == 0) | |
| { | |
| responses[i].text = strdup (kbi_passwd); | |
| responses[i].length = len; | |
| } | |
| } | |
| /* --------------------------------------------------------------------------------------------- */ | |
| /** | |
| * Open connection to host using password. | |
| * | |
| * @param super connection data | |
| * @param mcerror pointer to the error handler | |
| * @return TRUE if connection was successfully opened, FALSE otherwise | |
| */ | |
| static gboolean | |
| sftpfs_open_connection_ssh_password (struct vfs_s_super *super, GError ** mcerror) | |
| { | |
| sftpfs_super_t *sftpfs_super = SFTP_SUPER (super); | |
| char *p, *passwd; | |
| gboolean ret_value = FALSE; | |
| int rc; | |
| mc_return_val_if_error (mcerror, FALSE); | |
| if ((sftpfs_super->auth_type & PASSWORD) == 0) | |
| return FALSE; | |
| if (super->path_element->password != NULL) | |
| { | |
| while ((rc = libssh2_userauth_password (sftpfs_super->session, super->path_element->user, | |
| super->path_element->password)) == | |
| LIBSSH2_ERROR_EAGAIN); | |
| if (rc == 0) | |
| return TRUE; | |
| kbi_super = super; | |
| kbi_passwd = super->path_element->password; | |
| while ((rc = | |
| libssh2_userauth_keyboard_interactive (sftpfs_super->session, | |
| super->path_element->user, | |
| sftpfs_keyboard_interactive_helper)) == | |
| LIBSSH2_ERROR_EAGAIN) | |
| ; | |
| kbi_super = NULL; | |
| kbi_passwd = NULL; | |
| if (rc == 0) | |
| return TRUE; | |
| } | |
| p = g_strdup_printf (_("sftp: Enter password for %s "), super->path_element->user); | |
| passwd = vfs_get_password (p); | |
| g_free (p); | |
| if (passwd == NULL) | |
| mc_propagate_error (mcerror, 0, "%s", _("sftp: Password is empty.")); | |
| else | |
| { | |
| while ((rc = libssh2_userauth_password (sftpfs_super->session, super->path_element->user, | |
| passwd)) == LIBSSH2_ERROR_EAGAIN) | |
| ; | |
| if (rc != 0) | |
| { | |
| kbi_super = super; | |
| kbi_passwd = passwd; | |
| while ((rc = | |
| libssh2_userauth_keyboard_interactive (sftpfs_super->session, | |
| super->path_element->user, | |
| sftpfs_keyboard_interactive_helper)) == | |
| LIBSSH2_ERROR_EAGAIN) | |
| ; | |
| kbi_super = NULL; | |
| kbi_passwd = NULL; | |
| } | |
| if (rc == 0) | |
| { | |
| ret_value = TRUE; | |
| g_free (super->path_element->password); | |
| super->path_element->password = passwd; | |
| } | |
| else | |
| g_free (passwd); | |
| } | |
| return ret_value; | |
| } | |
| /* --------------------------------------------------------------------------------------------- */ | |
| /*** public functions ****************************************************************************/ | |
| /* --------------------------------------------------------------------------------------------- */ | |
| /** | |
| * Open new connection. | |
| * | |
| * @param super connection data | |
| * @param mcerror pointer to the error handler | |
| * @return 0 if success, -1 otherwise | |
| */ | |
| int | |
| sftpfs_open_connection (struct vfs_s_super *super, GError ** mcerror) | |
| { | |
| int rc; | |
| sftpfs_super_t *sftpfs_super = SFTP_SUPER (super); | |
| mc_return_val_if_error (mcerror, -1); | |
| /* | |
| * The application code is responsible for creating the socket | |
| * and establishing the connection | |
| */ | |
| sftpfs_super->socket_handle = sftpfs_open_socket (super, mcerror); | |
| if (sftpfs_super->socket_handle == LIBSSH2_INVALID_SOCKET) | |
| return (-1); | |
| /* Create a session instance */ | |
| sftpfs_super->session = libssh2_session_init (); | |
| if (sftpfs_super->session == NULL) | |
| return (-1); | |
| /* ... start it up. This will trade welcome banners, exchange keys, | |
| * and setup crypto, compression, and MAC layers | |
| */ | |
| #if LIBSSH2_VERSION_NUM < 0x010208 | |
| rc = libssh2_session_startup (sftpfs_super->session, sftpfs_super->socket_handle); | |
| #else | |
| rc = libssh2_session_handshake (sftpfs_super->session, | |
| (libssh2_socket_t) sftpfs_super->socket_handle); | |
| #endif | |
| if (rc != 0) | |
| { | |
| mc_propagate_error (mcerror, rc, "%s", _("sftp: Failure establishing SSH session")); | |
| return (-1); | |
| } | |
| /* At this point we havn't yet authenticated. The first thing to do | |
| * is check the hostkey's fingerprint against our known hosts Your app | |
| * may have it hard coded, may go to a file, may present it to the | |
| * user, that's your call | |
| */ | |
| sftpfs_super->fingerprint = | |
| libssh2_hostkey_hash (sftpfs_super->session, LIBSSH2_HOSTKEY_HASH_SHA1); | |
| if (!sftpfs_recognize_auth_types (super)) | |
| { | |
| int sftp_errno; | |
| sftp_errno = libssh2_session_last_errno (sftpfs_super->session); | |
| sftpfs_ssherror_to_gliberror (sftpfs_super, sftp_errno, mcerror); | |
| return (-1); | |
| } | |
| if (!sftpfs_open_connection_ssh_agent (super, mcerror) | |
| && !sftpfs_open_connection_ssh_key (super, mcerror) | |
| && !sftpfs_open_connection_ssh_password (super, mcerror)) | |
| return (-1); | |
| sftpfs_super->sftp_session = libssh2_sftp_init (sftpfs_super->session); | |
| if (sftpfs_super->sftp_session == NULL) | |
| return (-1); | |
| /* Since we have not set non-blocking, tell libssh2 we are blocking */ | |
| libssh2_session_set_blocking (sftpfs_super->session, 1); | |
| return 0; | |
| } | |
| /* --------------------------------------------------------------------------------------------- */ | |
| /** | |
| * Close connection. | |
| * | |
| * @param super connection data | |
| * @param shutdown_message message for shutdown functions | |
| * @param mcerror pointer to the error handler | |
| */ | |
| void | |
| sftpfs_close_connection (struct vfs_s_super *super, const char *shutdown_message, GError ** mcerror) | |
| { | |
| sftpfs_super_t *sftpfs_super = SFTP_SUPER (super); | |
| /* no mc_return_*_if_error() here because of abort open_connection handling too */ | |
| (void) mcerror; | |
| if (sftpfs_super->sftp_session != NULL) | |
| { | |
| libssh2_sftp_shutdown (sftpfs_super->sftp_session); | |
| sftpfs_super->sftp_session = NULL; | |
| } | |
| if (sftpfs_super->agent != NULL) | |
| { | |
| libssh2_agent_disconnect (sftpfs_super->agent); | |
| libssh2_agent_free (sftpfs_super->agent); | |
| sftpfs_super->agent = NULL; | |
| } | |
| sftpfs_super->fingerprint = NULL; | |
| if (sftpfs_super->session != NULL) | |
| { | |
| libssh2_session_disconnect (sftpfs_super->session, shutdown_message); | |
| libssh2_session_free (sftpfs_super->session); | |
| sftpfs_super->session = NULL; | |
| } | |
| if (sftpfs_super->socket_handle != LIBSSH2_INVALID_SOCKET) | |
| { | |
| close (sftpfs_super->socket_handle); | |
| sftpfs_super->socket_handle = LIBSSH2_INVALID_SOCKET; | |
| } | |
| } | |
| /* --------------------------------------------------------------------------------------------- */ |