/* Copyright (c) 2004-2006, Sara Golemon * All rights reserved. * * Redistribution and use in source and binary forms, * with or without modification, are permitted provided * that the following conditions are met: * * Redistributions of source code must retain the above * copyright notice, this list of conditions and the * following disclaimer. * * Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following * disclaimer in the documentation and/or other materials * provided with the distribution. * * Neither the name of the copyright holder nor the names * of any other contributors may be used to endorse or * promote products derived from this software without * specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY * OF SUCH DAMAGE. */ #include "libssh2_priv.h" #include #include #ifndef WIN32 #include #endif #include #include /* Needed for struct iovec on some platforms */ #ifdef HAVE_SYS_UIO_H #include #endif #ifdef HAVE_POLL # include #else # ifdef HAVE_SELECT # ifdef HAVE_SYS_SELECT_H # include # else # include # include # endif # endif #endif /* {{{ libssh2_packet_queue_listener * Queue a connection request for a listener */ inline int libssh2_packet_queue_listener(LIBSSH2_SESSION *session, unsigned char *data, unsigned long datalen) { /* Look for a matching listener */ unsigned char *s = data + (sizeof("forwarded-tcpip") - 1) + 5; unsigned long packet_len = 17 + (sizeof("Forward not requested") - 1); unsigned char *p, packet[17 + (sizeof("Forward not requested") - 1)]; /* packet_type(1) + channel(4) + reason(4) + descr(4) + lang(4) */ LIBSSH2_LISTENER *l = session->listeners; char failure_code = 1; /* SSH_OPEN_ADMINISTRATIVELY_PROHIBITED */ unsigned long sender_channel, initial_window_size, packet_size; unsigned char *host, *shost; unsigned long port, sport, host_len, shost_len; sender_channel = libssh2_ntohu32(s); s += 4; initial_window_size = libssh2_ntohu32(s); s += 4; packet_size = libssh2_ntohu32(s); s += 4; host_len = libssh2_ntohu32(s); s += 4; host = s; s += host_len; port = libssh2_ntohu32(s); s += 4; shost_len = libssh2_ntohu32(s); s += 4; shost = s; s += shost_len; sport = libssh2_ntohu32(s); s += 4; #ifdef LIBSSH2_DEBUG_CONNECTION _libssh2_debug(session, LIBSSH2_DBG_CONN, "Remote received connection from %s:%ld to %s:%ld", shost, sport, host, port); #endif while (l) { if ((l->port == port) && (strlen(l->host) == host_len) && (memcmp(l->host, host, host_len) == 0)) { /* This is our listener */ LIBSSH2_CHANNEL *channel, *last_queued = l->queue; if (l->queue_maxsize && (l->queue_maxsize <= l->queue_size)) { /* Queue is full */ failure_code = 4; /* SSH_OPEN_RESOURCE_SHORTAGE */ #ifdef LIBSSH2_DEBUG_CONNECTION _libssh2_debug(session, LIBSSH2_DBG_CONN, "Listener queue full, ignoring"); #endif break; } channel = LIBSSH2_ALLOC(session, sizeof(LIBSSH2_CHANNEL)); if (!channel) { libssh2_error(session, LIBSSH2_ERROR_ALLOC, "Unable to allocate a channel for new connection", 0); failure_code = 4; /* SSH_OPEN_RESOURCE_SHORTAGE */ break; } memset(channel, 0, sizeof(LIBSSH2_CHANNEL)); channel->session = session; channel->channel_type_len = sizeof("forwarded-tcpip") - 1; channel->channel_type = LIBSSH2_ALLOC(session, channel->channel_type_len + 1); if (!channel->channel_type) { libssh2_error(session, LIBSSH2_ERROR_ALLOC, "Unable to allocate a channel for new connection", 0); LIBSSH2_FREE(session, channel); failure_code = 4; /* SSH_OPEN_RESOURCE_SHORTAGE */ break; } memcpy(channel->channel_type, "forwarded-tcpip", channel->channel_type_len + 1); channel->remote.id = sender_channel; channel->remote.window_size_initial = LIBSSH2_CHANNEL_WINDOW_DEFAULT; channel->remote.window_size = LIBSSH2_CHANNEL_WINDOW_DEFAULT; channel->remote.packet_size = LIBSSH2_CHANNEL_PACKET_DEFAULT; channel->local.id = libssh2_channel_nextid(session); channel->local.window_size_initial = initial_window_size; channel->local.window_size = initial_window_size; channel->local.packet_size = packet_size; #ifdef LIBSSH2_DEBUG_CONNECTION _libssh2_debug(session, LIBSSH2_DBG_CONN, "Connection queued: channel %lu/%lu win %lu/%lu packet %lu/%lu", channel->local.id, channel->remote.id, channel->local.window_size, channel->remote.window_size, channel->local.packet_size, channel->remote.packet_size); #endif p = packet; *(p++) = SSH_MSG_CHANNEL_OPEN_CONFIRMATION; libssh2_htonu32(p, channel->remote.id); p += 4; libssh2_htonu32(p, channel->local.id); p += 4; libssh2_htonu32(p, channel->remote.window_size_initial); p += 4; libssh2_htonu32(p, channel->remote.packet_size); p += 4; if (libssh2_packet_write(session, packet, 17)) { libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND, "Unable to send channel open confirmation", 0); return -1; } /* Link the channel into the end of the queue list */ if (!last_queued) { l->queue = channel; return 0; } while (last_queued->next) last_queued = last_queued->next; last_queued->next = channel; channel->prev = last_queued; l->queue_size++; return 0; } l = l->next; } /* We're not listening to you */ { p = packet; *(p++) = SSH_MSG_CHANNEL_OPEN_FAILURE; libssh2_htonu32(p, sender_channel); p += 4; libssh2_htonu32(p, failure_code); p += 4; libssh2_htonu32(p, sizeof("Forward not requested") - 1); p += 4; memcpy(s, "Forward not requested", sizeof("Forward not requested") - 1); p += sizeof("Forward not requested") - 1; libssh2_htonu32(p, 0); if (libssh2_packet_write(session, packet, packet_len)) { libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND, "Unable to send open failure", 0); return -1; } return 0; } } /* }}} */ /* {{{ libssh2_packet_x11_open * Accept a forwarded X11 connection */ inline int libssh2_packet_x11_open(LIBSSH2_SESSION *session, unsigned char *data, unsigned long datalen) { int failure_code = 2; /* SSH_OPEN_CONNECT_FAILED */ unsigned char *s = data + (sizeof("x11") - 1) + 5; unsigned long packet_len = 17 + (sizeof("X11 Forward Unavailable") - 1); unsigned char *p, packet[17 + (sizeof("X11 Forward Unavailable") - 1)]; /* packet_type(1) + channel(4) + reason(4) + descr(4) + lang(4) */ LIBSSH2_CHANNEL *channel; unsigned long sender_channel, initial_window_size, packet_size; unsigned char *shost; unsigned long sport, shost_len; sender_channel = libssh2_ntohu32(s); s += 4; initial_window_size = libssh2_ntohu32(s); s += 4; packet_size = libssh2_ntohu32(s); s += 4; shost_len = libssh2_ntohu32(s); s += 4; shost = s; s += shost_len; sport = libssh2_ntohu32(s); s += 4; #ifdef LIBSSH2_DEBUG_CONNECTION _libssh2_debug(session, LIBSSH2_DBG_CONN, "X11 Connection Received from %s:%ld on channel %lu", shost, sport, sender_channel); #endif if (session->x11) { channel = LIBSSH2_ALLOC(session, sizeof(LIBSSH2_CHANNEL)); if (!channel) { libssh2_error(session, LIBSSH2_ERROR_ALLOC, "Unable to allocate a channel for new connection", 0); failure_code = 4; /* SSH_OPEN_RESOURCE_SHORTAGE */ goto x11_exit; } memset(channel, 0, sizeof(LIBSSH2_CHANNEL)); channel->session = session; channel->channel_type_len = sizeof("x11") - 1; channel->channel_type = LIBSSH2_ALLOC(session, channel->channel_type_len + 1); if (!channel->channel_type) { libssh2_error(session, LIBSSH2_ERROR_ALLOC, "Unable to allocate a channel for new connection", 0); LIBSSH2_FREE(session, channel); failure_code = 4; /* SSH_OPEN_RESOURCE_SHORTAGE */ goto x11_exit; } memcpy(channel->channel_type, "x11", channel->channel_type_len + 1); channel->remote.id = sender_channel; channel->remote.window_size_initial = LIBSSH2_CHANNEL_WINDOW_DEFAULT; channel->remote.window_size = LIBSSH2_CHANNEL_WINDOW_DEFAULT; channel->remote.packet_size = LIBSSH2_CHANNEL_PACKET_DEFAULT; channel->local.id = libssh2_channel_nextid(session); channel->local.window_size_initial = initial_window_size; channel->local.window_size = initial_window_size; channel->local.packet_size = packet_size; #ifdef LIBSSH2_DEBUG_CONNECTION _libssh2_debug(session, LIBSSH2_DBG_CONN, "X11 Connection established: channel %lu/%lu win %lu/%lu packet %lu/%lu", channel->local.id, channel->remote.id, channel->local.window_size, channel->remote.window_size, channel->local.packet_size, channel->remote.packet_size); #endif p = packet; *(p++) = SSH_MSG_CHANNEL_OPEN_CONFIRMATION; libssh2_htonu32(p, channel->remote.id); p += 4; libssh2_htonu32(p, channel->local.id); p += 4; libssh2_htonu32(p, channel->remote.window_size_initial); p += 4; libssh2_htonu32(p, channel->remote.packet_size); p += 4; if (libssh2_packet_write(session, packet, 17)) { libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND, "Unable to send channel open confirmation", 0); return -1; } /* Link the channel into the session */ if (session->channels.tail) { session->channels.tail->next = channel; channel->prev = session->channels.tail; } else { session->channels.head = channel; channel->prev = NULL; } channel->next = NULL; session->channels.tail = channel; /* Pass control to the callback, they may turn right around and free the channel, or actually use it */ LIBSSH2_X11_OPEN(channel, shost, sport); return 0; } else { failure_code = 4; /* SSH_OPEN_RESOURCE_SHORTAGE */ } x11_exit: p = packet; *(p++) = SSH_MSG_CHANNEL_OPEN_FAILURE; libssh2_htonu32(p, sender_channel); p += 4; libssh2_htonu32(p, failure_code); p += 4; libssh2_htonu32(p, sizeof("X11 Forward Unavailable") - 1); p += 4; memcpy(s, "X11 Forward Unavailable", sizeof("X11 Forward Unavailable") - 1); p += sizeof("X11 Forward Unavailable") - 1; libssh2_htonu32(p, 0); if (libssh2_packet_write(session, packet, packet_len)) { libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND, "Unable to send open failure", 0); return -1; } return 0; } /* }}} */ /* {{{ libssh2_packet_new * Create a new packet and attach it to the brigade */ static int libssh2_packet_add(LIBSSH2_SESSION *session, unsigned char *data, size_t datalen, int macstate) { LIBSSH2_PACKET *packet; unsigned long data_head = 0; #ifdef LIBSSH2_DEBUG_TRANSPORT _libssh2_debug(session, LIBSSH2_DBG_TRANS, "Packet type %d received, length=%d", (int)data[0], (int)datalen); #endif if (macstate == LIBSSH2_MAC_INVALID) { if (session->macerror) { if (LIBSSH2_MACERROR(session, data, datalen) == 0) { /* Calling app has given the OK, Process it anyway */ macstate = LIBSSH2_MAC_CONFIRMED; } else { libssh2_error(session, LIBSSH2_ERROR_INVALID_MAC, "Invalid Message Authentication Code received", 0); if (session->ssh_msg_disconnect) { LIBSSH2_DISCONNECT(session, SSH_DISCONNECT_MAC_ERROR, "Invalid MAC received", sizeof("Invalid MAC received") - 1, "", 0); } return -1; } } else { libssh2_error(session, LIBSSH2_ERROR_INVALID_MAC, "Invalid Message Authentication Code received", 0); if (session->ssh_msg_disconnect) { LIBSSH2_DISCONNECT(session, SSH_DISCONNECT_MAC_ERROR, "Invalid MAC received", sizeof("Invalid MAC received") - 1, "", 0); } return -1; } } /* A couple exceptions to the packet adding rule: */ switch (data[0]) { case SSH_MSG_DISCONNECT: { char *message, *language; int reason, message_len, language_len; reason = libssh2_ntohu32(data + 1); message_len = libssh2_ntohu32(data + 5); message = data + 9; /* packet_type(1) + reason(4) + message_len(4) */ language_len = libssh2_ntohu32(data + 9 + message_len); /* This is where we hack on the data a little, * Use the MSB of language_len to to a terminating NULL (In all liklihood it is already) * Shift the language tag back a byte (In all likelihood it's zero length anyway * Store a NULL in the last byte of the packet to terminate the language string * With the lengths passed this isn't *REALLY* necessary, but it's "kind" */ message[message_len] = '\0'; language = data + 9 + message_len + 3; if (language_len) { memcpy(language, language + 1, language_len); } language[language_len] = '\0'; if (session->ssh_msg_disconnect) { LIBSSH2_DISCONNECT(session, reason, message, message_len, language, language_len); } #ifdef LIBSSH2_DEBUG_TRANSPORT _libssh2_debug(session, LIBSSH2_DBG_TRANS, "Disconnect(%d): %s(%s)", reason, message, language); #endif LIBSSH2_FREE(session, data); session->socket_state = LIBSSH2_SOCKET_DISCONNECTED; return -1; } break; case SSH_MSG_IGNORE: /* As with disconnect, back it up one and add a trailing NULL */ memcpy(data + 4, data + 5, datalen - 5); data[datalen] = '\0'; if (session->ssh_msg_ignore) { LIBSSH2_IGNORE(session, data + 4, datalen - 5); } LIBSSH2_FREE(session, data); return 0; break; case SSH_MSG_DEBUG: { int always_display = data[0]; char *message, *language; int message_len, language_len; message_len = libssh2_ntohu32(data + 2); message = data + 6; /* packet_type(1) + display(1) + message_len(4) */ language_len = libssh2_ntohu32(data + 6 + message_len); /* This is where we hack on the data a little, * Use the MSB of language_len to to a terminating NULL (In all liklihood it is already) * Shift the language tag back a byte (In all likelihood it's zero length anyway * Store a NULL in the last byte of the packet to terminate the language string * With the lengths passed this isn't *REALLY* necessary, but it's "kind" */ message[message_len] = '\0'; language = data + 6 + message_len + 3; if (language_len) { memcpy(language, language + 1, language_len); } language[language_len] = '\0'; if (session->ssh_msg_debug) { LIBSSH2_DEBUG(session, always_display, message, message_len, language, language_len); } #ifdef LIBSSH2_DEBUG_TRANSPORT /* _libssh2_debug will actually truncate this for us so that it's not an inordinate about of data */ _libssh2_debug(session, LIBSSH2_DBG_TRANS, "Debug Packet: %s", message); #endif LIBSSH2_FREE(session, data); return 0; } break; case SSH_MSG_CHANNEL_EXTENDED_DATA: data_head += 4; /* streamid(4) */ case SSH_MSG_CHANNEL_DATA: data_head += 9; /* packet_type(1) + channelno(4) + datalen(4) */ { LIBSSH2_CHANNEL *channel = libssh2_channel_locate(session, libssh2_ntohu32(data + 1)); if (!channel) { libssh2_error(session, LIBSSH2_ERROR_CHANNEL_UNKNOWN, "Packet received for unknown channel, ignoring", 0); LIBSSH2_FREE(session, data); return 0; } #ifdef LIBSSH2_DEBUG_CONNECTION { unsigned long stream_id = 0; if (data[0] == SSH_MSG_CHANNEL_EXTENDED_DATA) { stream_id = libssh2_ntohu32(data + 5); } _libssh2_debug(session, LIBSSH2_DBG_CONN, "%d bytes received for channel %lu/%lu stream #%lu", (int)(datalen - data_head), channel->local.id, channel->remote.id, stream_id); } #endif if ((channel->remote.extended_data_ignore_mode == LIBSSH2_CHANNEL_EXTENDED_DATA_IGNORE) && (data[0] == SSH_MSG_CHANNEL_EXTENDED_DATA)) { /* Pretend we didn't receive this */ LIBSSH2_FREE(session, data); #ifdef LIBSSH2_DEBUG_CONNECTION _libssh2_debug(session, LIBSSH2_DBG_CONN, "Ignoring extended data and refunding %d bytes", (int)(datalen - 13)); #endif /* Adjust the window based on the block we just freed */ libssh2_channel_receive_window_adjust(channel, datalen - 13, 0); return 0; } /* REMEMBER! remote means remote as source of data, NOT remote window! */ if (channel->remote.packet_size < (datalen - data_head)) { /* Spec says we MAY ignore bytes sent beyond packet_size */ libssh2_error(session, LIBSSH2_ERROR_CHANNEL_PACKET_EXCEEDED, "Packet contains more data than we offered to receive, truncating", 0); datalen = channel->remote.packet_size + data_head; } if (channel->remote.window_size <= 0) { /* Spec says we MAY ignore bytes sent beyond window_size */ libssh2_error(session, LIBSSH2_ERROR_CHANNEL_WINDOW_EXCEEDED, "The current receive window is full, data ignored", 0); LIBSSH2_FREE(session, data); return 0; } /* Reset EOF status */ channel->remote.eof = 0; if ((datalen - data_head) > channel->remote.window_size) { libssh2_error(session, LIBSSH2_ERROR_CHANNEL_WINDOW_EXCEEDED, "Remote sent more data than current window allows, truncating", 0); datalen = channel->remote.window_size + data_head; } else { /* Now that we've received it, shrink our window */ channel->remote.window_size -= datalen - data_head; } } break; case SSH_MSG_CHANNEL_EOF: { LIBSSH2_CHANNEL *channel = libssh2_channel_locate(session, libssh2_ntohu32(data + 1)); if (!channel) { /* We may have freed already, just quietly ignore this... */ LIBSSH2_FREE(session, data); return 0; } #ifdef LIBSSH2_DEBUG_CONNECTION _libssh2_debug(session, LIBSSH2_DBG_CONN, "EOF received for channel %lu/%lu", channel->local.id, channel->remote.id); #endif channel->remote.eof = 1; LIBSSH2_FREE(session, data); return 0; } break; case SSH_MSG_CHANNEL_REQUEST: { if (libssh2_ntohu32(data+5) == sizeof("exit-status") - 1 && !memcmp("exit-status", data + 9, sizeof("exit-status") - 1)) { /* we've got "exit-status" packet. Set the session value */ LIBSSH2_CHANNEL *channel = libssh2_channel_locate(session, libssh2_ntohu32(data+1)); if (channel) { channel->exit_status = libssh2_ntohu32(data + 9 + sizeof("exit-status")); #ifdef LIBSSH2_DEBUG_CONNECTION _libssh2_debug(session, LIBSSH2_DBG_CONN, "Exit status %lu received for channel %lu/%lu", channel->exit_status, channel->local.id, channel->remote.id); #endif } LIBSSH2_FREE(session, data); return 0; } } break; case SSH_MSG_CHANNEL_CLOSE: { LIBSSH2_CHANNEL *channel = libssh2_channel_locate(session, libssh2_ntohu32(data + 1)); if (!channel) { /* We may have freed already, just quietly ignore this... */ LIBSSH2_FREE(session, data); return 0; } #ifdef LIBSSH2_DEBUG_CONNECTION _libssh2_debug(session, LIBSSH2_DBG_CONN, "Close received for channel %lu/%lu", channel->local.id, channel->remote.id); #endif channel->remote.close = 1; /* TODO: Add a callback for this */ LIBSSH2_FREE(session, data); return 0; } break; case SSH_MSG_CHANNEL_OPEN: if ((datalen >= (sizeof("forwarded-tcpip") + 4)) && ((sizeof("forwarded-tcpip")-1) == libssh2_ntohu32(data + 1)) && (memcmp(data + 5, "forwarded-tcpip", sizeof("forwarded-tcpip") - 1) == 0)) { int retval = libssh2_packet_queue_listener(session, data, datalen); LIBSSH2_FREE(session, data); return retval; } if ((datalen >= (sizeof("x11") + 4)) && ((sizeof("x11")-1) == libssh2_ntohu32(data + 1)) && (memcmp(data + 5, "x11", sizeof("x11") - 1) == 0)) { int retval = libssh2_packet_x11_open(session, data, datalen); LIBSSH2_FREE(session, data); return retval; } break; case SSH_MSG_CHANNEL_WINDOW_ADJUST: { LIBSSH2_CHANNEL *channel = libssh2_channel_locate(session, libssh2_ntohu32(data + 1)); unsigned long bytestoadd = libssh2_ntohu32(data + 5); if (channel && bytestoadd) { channel->local.window_size += bytestoadd; } #ifdef LIBSSH2_DEBUG_CONNECTION _libssh2_debug(session, LIBSSH2_DBG_CONN, "Window adjust received for channel %lu/%lu, adding %lu bytes, new window_size=%lu", channel->local.id, channel->remote.id, bytestoadd, channel->local.window_size); #endif LIBSSH2_FREE(session, data); return 0; } break; } packet = LIBSSH2_ALLOC(session, sizeof(LIBSSH2_PACKET)); memset(packet, 0, sizeof(LIBSSH2_PACKET)); packet->data = data; packet->data_len = datalen; packet->data_head = data_head; packet->mac = macstate; packet->brigade = &session->packets; packet->next = NULL; if (session->packets.tail) { packet->prev = session->packets.tail; packet->prev->next = packet; session->packets.tail = packet; } else { session->packets.head = packet; session->packets.tail = packet; packet->prev = NULL; } if (data[0] == SSH_MSG_KEXINIT && !(session->state & LIBSSH2_STATE_EXCHANGING_KEYS)) { /* Remote wants new keys * Well, it's already in the brigade, * let's just call back into ourselves */ #ifdef LIBSSH2_DEBUG_TRANSPORT _libssh2_debug(session, LIBSSH2_DBG_TRANS, "Renegotiating Keys"); #endif libssh2_kex_exchange(session, 1); /* If there was a key reexchange failure, let's just hope we didn't send NEWKEYS yet, otherwise remote will drop us like a rock */ } return 0; } /* }}} */ /* {{{ libssh2_blocking_read * Force a blocking read, regardless of socket settings */ static int libssh2_blocking_read(LIBSSH2_SESSION *session, unsigned char *buf, size_t count) { size_t bytes_read = 0; #if !defined(HAVE_POLL) && !defined(HAVE_SELECT) int polls = 0; #endif #ifndef WIN32 fcntl(session->socket_fd, F_SETFL, 0); #else { u_long block = FALSE; ioctlsocket(session->socket_fd, FIONBIO, &block); } #endif #ifdef LIBSSH2_DEBUG_TRANSPORT _libssh2_debug(session, LIBSSH2_DBG_TRANS, "Blocking read: %d bytes", (int)count); #endif while (bytes_read < count) { int ret; ret = recv(session->socket_fd, buf + bytes_read, count - bytes_read, LIBSSH2_SOCKET_RECV_FLAGS(session)); if (ret < 0) { #ifdef WIN32 switch (WSAGetLastError()) { case WSAEWOULDBLOCK: errno = EAGAIN; break; case WSAENOTSOCK: errno = EBADF; break; case WSAENOTCONN: case WSAECONNABORTED: errno = ENOTCONN; break; case WSAEINTR: errno = EINTR; break; } #endif if (errno == EAGAIN) { #ifdef HAVE_POLL struct pollfd read_socket; read_socket.fd = session->socket_fd; read_socket.events = POLLIN; if (poll(&read_socket, 1, 30000) <= 0) { return -1; } #elif defined(HAVE_SELECT) fd_set read_socket; struct timeval timeout; FD_ZERO(&read_socket); FD_SET(session->socket_fd, &read_socket); timeout.tv_sec = 30; timeout.tv_usec = 0; if (select(session->socket_fd + 1, &read_socket, NULL, NULL, &timeout) <= 0) { return -1; } #else if (polls++ > LIBSSH2_SOCKET_POLL_MAXLOOPS) { return -1; } u_sleep(LIBSSH2_SOCKET_POLL_UDELAY); #endif /* POLL/SELECT/SLEEP */ continue; } if (errno == EINTR) { continue; } if ((errno == EBADF) || (errno == EIO) || (errno == ENOTCONN)) { session->socket_state = LIBSSH2_SOCKET_DISCONNECTED; } return -1; } if (ret == 0) continue; bytes_read += ret; } #ifdef LIBSSH2_DEBUG_TRANSPORT _libssh2_debug(session, LIBSSH2_DBG_TRANS, "Blocking read: %d bytes actually read", (int)bytes_read); #endif return bytes_read; } /* }}} */ /* {{{ libssh2_packet_read * Collect a packet into the input brigade * block only controls whether or not to wait for a packet to start, * Once a packet starts, libssh2 will block until it is complete * Returns packet type added to input brigade (0 if nothing added), or -1 on failure */ int libssh2_packet_read(LIBSSH2_SESSION *session, int should_block) { int packet_type = -1; if (session->socket_state == LIBSSH2_SOCKET_DISCONNECTED) { return 0; } #ifndef WIN32 fcntl(session->socket_fd, F_SETFL, O_NONBLOCK); #else { u_long non_block = TRUE; ioctlsocket(session->socket_fd, FIONBIO, &non_block); } #endif #ifdef LIBSSH2_DEBUG_TRANSPORT _libssh2_debug(session, LIBSSH2_DBG_TRANS, "Checking for packet: will%s block", should_block ? "" : " not"); #endif if (session->state & LIBSSH2_STATE_NEWKEYS) { /* Temporary Buffer * The largest blocksize (currently) is 32, the largest MAC (currently) is 20 */ unsigned char block[2 * 32], *payload, *s, tmp[6]; long read_len; unsigned long blocksize = session->remote.crypt->blocksize; unsigned long packet_len, payload_len; int padding_len; int macstate; int free_payload = 1; /* Safely ignored in CUSTOM cipher mode */ EVP_CIPHER_CTX *ctx = (EVP_CIPHER_CTX *)session->remote.crypt_abstract; /* Note: If we add any cipher with a blocksize less than 6 we'll need to get more creative with this * For now, all blocksize sizes are 8+ */ if (should_block) { read_len = libssh2_blocking_read(session, block, blocksize); } else { read_len = recv(session->socket_fd, block, 1, LIBSSH2_SOCKET_RECV_FLAGS(session)); if (read_len <= 0) { return 0; } read_len += libssh2_blocking_read(session, block + read_len, blocksize - read_len); } if (read_len < blocksize) { return (session->socket_state == LIBSSH2_SOCKET_DISCONNECTED) ? 0 : -1; } if (session->remote.crypt->flags & LIBSSH2_CRYPT_METHOD_FLAG_EVP) { EVP_Cipher(ctx, block + blocksize, block, blocksize); memcpy(block, block + blocksize, blocksize); } else { if (session->remote.crypt->crypt(session, block, &session->remote.crypt_abstract)) { libssh2_error(session, LIBSSH2_ERROR_DECRYPT, "Error decrypting packet preamble", 0); return -1; } } packet_len = libssh2_ntohu32(block); padding_len = block[4]; #ifdef LIBSSH2_DEBUG_TRANSPORT _libssh2_debug(session, LIBSSH2_DBG_TRANS, "Processing packet %lu bytes long (with %lu bytes padding)", packet_len, padding_len); #endif memcpy(tmp, block, 5); /* Use this for MAC later */ payload_len = packet_len - 1; /* padding_len(1) */ /* Sanity Check */ if ((payload_len > LIBSSH2_PACKET_MAXPAYLOAD) || ((packet_len + 4) % blocksize)) { /* If something goes horribly wrong during the decryption phase, just bailout and die gracefully */ session->socket_state = LIBSSH2_SOCKET_DISCONNECTED; libssh2_error(session, LIBSSH2_ERROR_PROTO, "Fatal protocol error, invalid payload size", 0); return -1; } s = payload = LIBSSH2_ALLOC(session, payload_len); memcpy(s, block + 5, blocksize - 5); s += blocksize - 5; while ((s - payload) < payload_len) { read_len = libssh2_blocking_read(session, block, blocksize); if (read_len < blocksize) { LIBSSH2_FREE(session, payload); return -1; } if (session->remote.crypt->flags & LIBSSH2_CRYPT_METHOD_FLAG_EVP) { EVP_Cipher(ctx, block + blocksize, block, blocksize); memcpy(s, block + blocksize, blocksize); } else { if (session->remote.crypt->crypt(session, block, &session->remote.crypt_abstract)) { libssh2_error(session, LIBSSH2_ERROR_DECRYPT, "Error decrypting packet preamble", 0); LIBSSH2_FREE(session, payload); return -1; } memcpy(s, block, blocksize); } s += blocksize; } read_len = libssh2_blocking_read(session, block, session->remote.mac->mac_len); if (read_len < session->remote.mac->mac_len) { LIBSSH2_FREE(session, payload); return -1; } /* Calculate MAC hash */ session->remote.mac->hash(session, block + session->remote.mac->mac_len, session->remote.seqno, tmp, 5, payload, payload_len, &session->remote.mac_abstract); macstate = (strncmp(block, block + session->remote.mac->mac_len, session->remote.mac->mac_len) == 0) ? LIBSSH2_MAC_CONFIRMED : LIBSSH2_MAC_INVALID; session->remote.seqno++; /* Ignore padding */ payload_len -= padding_len; if (session->remote.comp && strcmp(session->remote.comp->name, "none")) { /* Decompress */ unsigned char *data; unsigned long data_len; if (session->remote.comp->comp(session, 0, &data, &data_len, LIBSSH2_PACKET_MAXDECOMP, &free_payload, payload, payload_len, &session->remote.comp_abstract)) { LIBSSH2_FREE(session, payload); return -1; } #ifdef LIBSSH2_DEBUG_TRANSPORT _libssh2_debug(session, LIBSSH2_DBG_TRANS, "Payload decompressed: %lu bytes(compressed) to %lu bytes(uncompressed)", data_len, payload_len); #endif if (free_payload) { LIBSSH2_FREE(session, payload); payload = data; payload_len = data_len; } else { if (data == payload) { /* It's not to be freed, because the compression layer reused payload, * So let's do the same! */ payload_len = data_len; } else { /* No comp_method actually lets this happen, but let's prepare for the future */ LIBSSH2_FREE(session, payload); /* We need a freeable struct otherwise the brigade won't know what to do with it */ payload = LIBSSH2_ALLOC(session, data_len); if (!payload) { libssh2_error(session, LIBSSH2_ERROR_ALLOC, "Unable to allocate memory for copy of uncompressed data", 0); return -1; } memcpy(payload, data, data_len); payload_len = data_len; } } } packet_type = payload[0]; libssh2_packet_add(session, payload, payload_len, macstate); } else { /* No cipher active */ unsigned char *payload; unsigned char buf[24]; unsigned long buf_len, payload_len; unsigned long packet_length; unsigned long padding_length; if (should_block) { buf_len = libssh2_blocking_read(session, buf, 5); } else { buf_len = recv(session->socket_fd, buf, 1, LIBSSH2_SOCKET_RECV_FLAGS(session)); if (buf_len <= 0) { return 0; } buf_len += libssh2_blocking_read(session, buf, 5 - buf_len); } if (buf_len < 5) { /* Something bad happened */ return -1; } packet_length = libssh2_ntohu32(buf); padding_length = buf[4]; #ifdef LIBSSH2_DEBUG_TRANSPORT _libssh2_debug(session, LIBSSH2_DBG_TRANS, "Processing plaintext packet %lu bytes long (with %lu bytes padding)", packet_length, padding_length); #endif payload_len = packet_length - padding_length - 1; /* padding_length(1) */ payload = LIBSSH2_ALLOC(session, payload_len); if (!payload) { libssh2_error(session, LIBSSH2_ERROR_ALLOC, "Unable to allocate memory for copy of plaintext data", 0); return -1; } if (libssh2_blocking_read(session, payload, payload_len) < payload_len) { return (session->socket_state == LIBSSH2_SOCKET_DISCONNECTED) ? 0 : -1; } while (padding_length) { int l; /* Flush padding */ l = libssh2_blocking_read(session, buf, padding_length); if (l > 0) padding_length -= l; else break; } packet_type = payload[0]; /* MACs don't exist in non-encrypted mode */ libssh2_packet_add(session, payload, payload_len, LIBSSH2_MAC_CONFIRMED); session->remote.seqno++; } return packet_type; } /* }}} */ /* {{{ libssh2_packet_ask * Scan the brigade for a matching packet type, optionally poll the socket for a packet first */ int libssh2_packet_ask_ex(LIBSSH2_SESSION *session, unsigned char packet_type, unsigned char **data, unsigned long *data_len, unsigned long match_ofs, const unsigned char *match_buf, unsigned long match_len, int poll_socket) { LIBSSH2_PACKET *packet = session->packets.head; if (poll_socket) { if (libssh2_packet_read(session, 0) < 0) { return -1; } } #ifdef LIBSSH2_DEBUG_TRANSPORT _libssh2_debug(session, LIBSSH2_DBG_TRANS, "Looking for packet of type: %d", (int)packet_type); #endif while (packet) { if (packet->data[0] == packet_type && (packet->data_len >= (match_ofs + match_len)) && (!match_buf || (memcmp(packet->data + match_ofs, match_buf, match_len) == 0))) { *data = packet->data; *data_len = packet->data_len; if (packet->prev) { packet->prev->next = packet->next; } else { session->packets.head = packet->next; } if (packet->next) { packet->next->prev = packet->prev; } else { session->packets.tail = packet->prev; } LIBSSH2_FREE(session, packet); return 0; } packet = packet->next; } return -1; } /* }}} */ /* {{{ libssh2_packet_askv * Scan for any of a list of packet types in the brigade, optionally poll the socket for a packet first */ int libssh2_packet_askv_ex(LIBSSH2_SESSION *session, unsigned char *packet_types, unsigned char **data, unsigned long *data_len, unsigned long match_ofs, const unsigned char *match_buf, unsigned long match_len, int poll_socket) { int i, packet_types_len = strlen(packet_types); for(i = 0; i < packet_types_len; i++) { if (0 == libssh2_packet_ask_ex(session, packet_types[i], data, data_len, match_ofs, match_buf, match_len, i ? 0 : poll_socket)) { return 0; } } return -1; } /* }}} */ /* {{{ libssh2_packet_require * Loops libssh2_packet_read() until the packet requested is available * SSH_DISCONNECT or a SOCKET_DISCONNECTED will cause a bailout */ int libssh2_packet_require_ex(LIBSSH2_SESSION *session, unsigned char packet_type, unsigned char **data, unsigned long *data_len, unsigned long match_ofs, const unsigned char *match_buf, unsigned long match_len) { if (libssh2_packet_ask_ex(session, packet_type, data, data_len, match_ofs, match_buf, match_len, 0) == 0) { /* A packet was available in the packet brigade */ return 0; } #ifdef LIBSSH2_DEBUG_TRANSPORT _libssh2_debug(session, LIBSSH2_DBG_TRANS, "Blocking until packet of type %d becomes available", (int)packet_type); #endif while (session->socket_state == LIBSSH2_SOCKET_CONNECTED) { int ret = libssh2_packet_read(session, 1); if (ret < 0) { return -1; } if (ret == 0) continue; if (packet_type == ret) { /* Be lazy, let packet_ask pull it out of the brigade */ return libssh2_packet_ask_ex(session, packet_type, data, data_len, match_ofs, match_buf, match_len, 0); } } /* Only reached if the socket died */ return -1; } /* }}} */ /* {{{ libssh2_packet_burn * Loops libssh2_packet_read() until any packet is available and promptly discards it * Used during KEX exchange to discard badly guessed KEX_INIT packets */ int libssh2_packet_burn(LIBSSH2_SESSION *session) { unsigned char *data; unsigned long data_len; char all_packets[255]; int i; for(i = 1; i < 256; i++) all_packets[i - 1] = i; if (libssh2_packet_askv_ex(session, all_packets, &data, &data_len, 0, NULL, 0, 0) == 0) { i = data[0]; /* A packet was available in the packet brigade, burn it */ LIBSSH2_FREE(session, data); return i; } #ifdef LIBSSH2_DEBUG_TRANSPORT _libssh2_debug(session, LIBSSH2_DBG_TRANS, "Blocking until packet becomes available to burn"); #endif while (session->socket_state == LIBSSH2_SOCKET_CONNECTED) { int ret = libssh2_packet_read(session, 1); if (ret < 0) { return -1; } if (ret == 0) continue; /* Be lazy, let packet_ask pull it out of the brigade */ if (0 == libssh2_packet_ask_ex(session, ret, &data, &data_len, 0, NULL, 0, 0)) { /* Smoke 'em if you got 'em */ LIBSSH2_FREE(session, data); return ret; } } /* Only reached if the socket died */ return -1; } /* }}} */ /* {{{ libssh2_packet_requirev * Loops libssh2_packet_read() until one of a list of packet types requested is available * SSH_DISCONNECT or a SOCKET_DISCONNECTED will cause a bailout * packet_types is a null terminated list of packet_type numbers */ int libssh2_packet_requirev_ex(LIBSSH2_SESSION *session, unsigned char *packet_types, unsigned char **data, unsigned long *data_len, unsigned long match_ofs, const unsigned char *match_buf, unsigned long match_len) { if (libssh2_packet_askv_ex(session, packet_types, data, data_len, match_ofs, match_buf, match_len, 0) == 0) { /* One of the packets listed was available in the packet brigade */ return 0; } while (session->socket_state != LIBSSH2_SOCKET_DISCONNECTED) { int ret = libssh2_packet_read(session, 1); if (ret < 0) { return -1; } if (ret == 0) { continue; } if (strchr(packet_types, ret)) { /* Be lazy, let packet_ask pull it out of the brigade */ return libssh2_packet_askv_ex(session, packet_types, data, data_len, match_ofs, match_buf, match_len, 0); } } /* Only reached if the socket died */ return -1; } /* }}} */ /* {{{ libssh2_packet_write * Send a packet, encrypting it and adding a MAC code if necessary * Returns 0 on success, non-zero on failure */ int libssh2_packet_write(LIBSSH2_SESSION *session, unsigned char *data, unsigned long data_len) { unsigned long packet_length = data_len + 1; unsigned long block_size = (session->state & LIBSSH2_STATE_NEWKEYS) ? session->local.crypt->blocksize : 8; /* At this point packet_length doesn't include the packet_len field itself */ unsigned long padding_length; int free_data = 0; unsigned char buf[246]; /* 6 byte header plus max padding size(240) */ #ifdef LIBSSH2_DEBUG_TRANSPORT { /* Show a hint of what's being sent */ char excerpt[32]; int ex_len = 0, db_ofs = 0; for (; ex_len < 24 && db_ofs < data_len; ex_len += 3, db_ofs++) snprintf(excerpt + ex_len, 4, "%02X ", data[db_ofs]); _libssh2_debug(session, LIBSSH2_DBG_TRANS, "Sending packet type %d, length=%lu, %s", (int)data[0], data_len, excerpt); } #endif if ((session->state & LIBSSH2_STATE_NEWKEYS) && strcmp(session->local.comp->name, "none")) { if (session->local.comp->comp(session, 1, &data, &data_len, LIBSSH2_PACKET_MAXCOMP, &free_data, data, data_len, &session->local.comp_abstract)) { return -1; } #ifdef LIBSSH2_DEBUG_TRANSPORT _libssh2_debug(session, LIBSSH2_DBG_TRANS, "Compressed payload to %lu bytes", data_len); #endif } #ifndef WIN32 fcntl(session->socket_fd, F_SETFL, 0); #else { u_long non_block = FALSE; ioctlsocket(session->socket_fd, FIONBIO, &non_block); } #endif packet_length = data_len + 1; /* padding_length(1) -- MAC doesn't count -- Padding to be added soon */ padding_length = block_size - ((packet_length + 4) % block_size); if (padding_length < 4) { padding_length += block_size; } /* TODO: Maybe add 1 or 2 times block_size to padding_length randomly -- shake things up a bit... */ packet_length += padding_length; libssh2_htonu32(buf, packet_length); buf[4] = padding_length; #ifdef LIBSSH2_DEBUG_TRANSPORT _libssh2_debug(session, LIBSSH2_DBG_TRANS, "Sending packet with total length %lu (%lu bytes padding)", packet_length, padding_length); #endif if (session->state & LIBSSH2_STATE_NEWKEYS) { /* Encryption is in effect */ unsigned char *encbuf, *s; int ret; /* Safely ignored in CUSTOM cipher mode */ EVP_CIPHER_CTX *ctx = (EVP_CIPHER_CTX *)session->local.crypt_abstract; /* include packet_length(4) itself and room for the hash at the end */ encbuf = LIBSSH2_ALLOC(session, 4 + packet_length + session->local.mac->mac_len); if (!encbuf) { libssh2_error(session, LIBSSH2_ERROR_ALLOC, "Unable to allocate encryption buffer", 0); if (free_data) { LIBSSH2_FREE(session, data); } return -1; } /* Copy packet to encoding buffer */ memcpy(encbuf, buf, 5); memcpy(encbuf + 5, data, data_len); RAND_bytes(encbuf + 5 + data_len, padding_length); if (free_data) { LIBSSH2_FREE(session, data); } /* Calculate MAC hash */ session->local.mac->hash(session, encbuf + 4 + packet_length , session->local.seqno, encbuf, 4 + packet_length, NULL, 0, &session->local.mac_abstract); /* Encrypt data */ for(s = encbuf; (s - encbuf) < (4 + packet_length) ; s += session->local.crypt->blocksize) { if (session->local.crypt->flags & LIBSSH2_CRYPT_METHOD_FLAG_EVP) { EVP_Cipher(ctx, buf, s, session->local.crypt->blocksize); memcpy(s, buf, session->local.crypt->blocksize); } else { session->local.crypt->crypt(session, s, &session->local.crypt_abstract); } } session->local.seqno++; /* Send It */ ret = ((4 + packet_length + session->local.mac->mac_len) == send(session->socket_fd, encbuf, 4 + packet_length + session->local.mac->mac_len, LIBSSH2_SOCKET_SEND_FLAGS(session))) ? 0 : -1; /* Cleanup environment */ LIBSSH2_FREE(session, encbuf); return ret; } else { /* LIBSSH2_ENDPOINT_CRYPT_NONE */ /* Simplified write for non-encrypted mode */ struct iovec data_vector[3]; /* Using vectors means we don't have to alloc a new buffer -- a byte saved is a byte earned * No MAC during unencrypted phase */ data_vector[0].iov_base = buf; data_vector[0].iov_len = 5; data_vector[1].iov_base = (char*)data; data_vector[1].iov_len = data_len; data_vector[2].iov_base = buf + 5; data_vector[2].iov_len = padding_length; session->local.seqno++; /* Ignore this, it can't actually happen :) */ if (free_data) { LIBSSH2_FREE(session, data); } return ((packet_length + 4) == writev(session->socket_fd, data_vector, 3)) ? 0 : 1; } } /* }}} */