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Copy pathpacket.c
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1661 lines (1459 loc) · 63.9 KB
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/* Copyright (C) Sara Golemon <sarag@libssh2.org>
* Copyright (C) Mikhail Gusarov
* Copyright (C) Daniel Stenberg
* Copyright (C) Simon Josefsson
* 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.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include "libssh2_priv.h"
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_INTTYPES_H
#include <inttypes.h>
#endif
/* Needed for struct iovec on some platforms */
#ifdef HAVE_SYS_UIO_H
#include <sys/uio.h>
#endif
#include "transport.h"
#include "channel.h"
#include "packet.h"
/*
* libssh2_packet_queue_listener
*
* Queue a connection request for a listener
*/
static inline int
packet_queue_listener(LIBSSH2_SESSION * session, unsigned char *data,
size_t datalen,
packet_queue_listener_state_t *listen_state)
{
/*
* Look for a matching listener
*/
/* 17 = packet_type(1) + channel(4) + reason(4) + descr(4) + lang(4) */
size_t packet_len = 17 + strlen(FwdNotReq);
unsigned char *p;
LIBSSH2_LISTENER *listn = _libssh2_list_first(&session->listeners);
char failure_code = SSH_OPEN_ADMINISTRATIVELY_PROHIBITED;
int rc;
if(listen_state->state == libssh2_NB_state_idle) {
size_t offset = strlen("forwarded-tcpip") + 5;
size_t temp_len = 0;
struct string_buf buf;
buf.data = data;
buf.dataptr = buf.data;
buf.len = datalen;
if(datalen < offset) {
return _libssh2_error(session, LIBSSH2_ERROR_OUT_OF_BOUNDARY,
"Unexpected packet size");
}
buf.dataptr += offset;
if(_libssh2_get_u32(&buf, &(listen_state->sender_channel))) {
return _libssh2_error(session, LIBSSH2_ERROR_BUFFER_TOO_SMALL,
"Data too short extracting channel");
}
if(_libssh2_get_u32(&buf, &(listen_state->initial_window_size))) {
return _libssh2_error(session, LIBSSH2_ERROR_BUFFER_TOO_SMALL,
"Data too short extracting window size");
}
if(_libssh2_get_u32(&buf, &(listen_state->packet_size))) {
return _libssh2_error(session, LIBSSH2_ERROR_BUFFER_TOO_SMALL,
"Data too short extracting packet");
}
if(_libssh2_get_string(&buf, &(listen_state->host), &temp_len)) {
return _libssh2_error(session, LIBSSH2_ERROR_BUFFER_TOO_SMALL,
"Data too short extracting host");
}
listen_state->host_len = (uint32_t)temp_len;
if(_libssh2_get_u32(&buf, &(listen_state->port))) {
return _libssh2_error(session, LIBSSH2_ERROR_BUFFER_TOO_SMALL,
"Data too short extracting port");
}
if(_libssh2_get_string(&buf, &(listen_state->shost), &temp_len)) {
return _libssh2_error(session, LIBSSH2_ERROR_BUFFER_TOO_SMALL,
"Data too short extracting shost");
}
listen_state->shost_len = (uint32_t)temp_len;
if(_libssh2_get_u32(&buf, &(listen_state->sport))) {
return _libssh2_error(session, LIBSSH2_ERROR_BUFFER_TOO_SMALL,
"Data too short extracting sport");
}
_libssh2_debug((session, LIBSSH2_TRACE_CONN,
"Remote received connection from %s:%u to %s:%u",
listen_state->shost, listen_state->sport,
listen_state->host, listen_state->port));
listen_state->state = libssh2_NB_state_allocated;
}
if(listen_state->state != libssh2_NB_state_sent) {
while(listn) {
if((listn->port == (int) listen_state->port) &&
(strlen(listn->host) == listen_state->host_len) &&
(memcmp(listn->host, listen_state->host,
listen_state->host_len) == 0)) {
/* This is our listener */
LIBSSH2_CHANNEL *channel = NULL;
listen_state->channel = NULL;
if(listen_state->state == libssh2_NB_state_allocated) {
if(listn->queue_maxsize &&
(listn->queue_maxsize <= listn->queue_size)) {
/* Queue is full */
failure_code = SSH_OPEN_RESOURCE_SHORTAGE;
_libssh2_debug((session, LIBSSH2_TRACE_CONN,
"Listener queue full, ignoring"));
listen_state->state = libssh2_NB_state_sent;
break;
}
channel = LIBSSH2_CALLOC(session, sizeof(LIBSSH2_CHANNEL));
if(!channel) {
_libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate a channel for "
"new connection");
failure_code = SSH_OPEN_RESOURCE_SHORTAGE;
listen_state->state = libssh2_NB_state_sent;
break;
}
listen_state->channel = channel;
channel->session = session;
channel->channel_type_len = strlen("forwarded-tcpip");
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");
LIBSSH2_FREE(session, channel);
failure_code = SSH_OPEN_RESOURCE_SHORTAGE;
listen_state->state = libssh2_NB_state_sent;
break;
}
memcpy(channel->channel_type, "forwarded-tcpip",
channel->channel_type_len + 1);
channel->remote.id = listen_state->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 =
listen_state->initial_window_size;
channel->local.window_size =
listen_state->initial_window_size;
channel->local.packet_size = listen_state->packet_size;
_libssh2_debug((session, LIBSSH2_TRACE_CONN,
"Connection queued: channel %u/%u "
"win %u/%u packet %u/%u",
channel->local.id, channel->remote.id,
channel->local.window_size,
channel->remote.window_size,
channel->local.packet_size,
channel->remote.packet_size));
p = listen_state->packet;
*(p++) = SSH_MSG_CHANNEL_OPEN_CONFIRMATION;
_libssh2_store_u32(&p, channel->remote.id);
_libssh2_store_u32(&p, channel->local.id);
_libssh2_store_u32(&p,
channel->remote.window_size_initial);
_libssh2_store_u32(&p, channel->remote.packet_size);
listen_state->state = libssh2_NB_state_created;
}
if(listen_state->state == libssh2_NB_state_created) {
rc = _libssh2_transport_send(session, listen_state->packet,
17, NULL, 0);
if(rc == LIBSSH2_ERROR_EAGAIN)
return rc;
else if(rc) {
listen_state->state = libssh2_NB_state_idle;
return _libssh2_error(session, rc,
"Unable to send channel "
"open confirmation");
}
/* Link the channel into the end of the queue list */
if(listen_state->channel) {
_libssh2_list_add(&listn->queue,
&listen_state->channel->node);
listn->queue_size++;
}
listen_state->state = libssh2_NB_state_idle;
return 0;
}
}
listn = _libssh2_list_next(&listn->node);
}
listen_state->state = libssh2_NB_state_sent;
}
/* We're not listening to you */
p = listen_state->packet;
*(p++) = SSH_MSG_CHANNEL_OPEN_FAILURE;
_libssh2_store_u32(&p, listen_state->sender_channel);
_libssh2_store_u32(&p, failure_code);
_libssh2_store_str(&p, FwdNotReq, strlen(FwdNotReq));
_libssh2_htonu32(p, 0);
rc = _libssh2_transport_send(session, listen_state->packet,
packet_len, NULL, 0);
if(rc == LIBSSH2_ERROR_EAGAIN) {
return rc;
}
else if(rc) {
listen_state->state = libssh2_NB_state_idle;
return _libssh2_error(session, rc, "Unable to send open failure");
}
listen_state->state = libssh2_NB_state_idle;
return 0;
}
/*
* packet_x11_open
*
* Accept a forwarded X11 connection
*/
static inline int
packet_x11_open(LIBSSH2_SESSION * session, unsigned char *data,
size_t datalen,
packet_x11_open_state_t *x11open_state)
{
int failure_code = SSH_OPEN_CONNECT_FAILED;
/* 17 = packet_type(1) + channel(4) + reason(4) + descr(4) + lang(4) */
size_t packet_len = 17 + strlen(X11FwdUnAvil);
unsigned char *p;
LIBSSH2_CHANNEL *channel = x11open_state->channel;
int rc;
if(x11open_state->state == libssh2_NB_state_idle) {
size_t offset = strlen("x11") + 5;
size_t temp_len = 0;
struct string_buf buf;
buf.data = data;
buf.dataptr = buf.data;
buf.len = datalen;
if(datalen < offset) {
_libssh2_error(session, LIBSSH2_ERROR_INVAL,
"unexpected data length");
failure_code = SSH_OPEN_CONNECT_FAILED;
goto x11_exit;
}
buf.dataptr += offset;
if(_libssh2_get_u32(&buf, &(x11open_state->sender_channel))) {
_libssh2_error(session, LIBSSH2_ERROR_INVAL,
"unexpected sender channel size");
failure_code = SSH_OPEN_CONNECT_FAILED;
goto x11_exit;
}
if(_libssh2_get_u32(&buf, &(x11open_state->initial_window_size))) {
_libssh2_error(session, LIBSSH2_ERROR_INVAL,
"unexpected window size");
failure_code = SSH_OPEN_CONNECT_FAILED;
goto x11_exit;
}
if(_libssh2_get_u32(&buf, &(x11open_state->packet_size))) {
_libssh2_error(session, LIBSSH2_ERROR_INVAL,
"unexpected window size");
failure_code = SSH_OPEN_CONNECT_FAILED;
goto x11_exit;
}
if(_libssh2_get_string(&buf, &(x11open_state->shost), &temp_len)) {
_libssh2_error(session, LIBSSH2_ERROR_INVAL,
"unexpected host size");
failure_code = SSH_OPEN_CONNECT_FAILED;
goto x11_exit;
}
x11open_state->shost_len = (uint32_t)temp_len;
if(_libssh2_get_u32(&buf, &(x11open_state->sport))) {
_libssh2_error(session, LIBSSH2_ERROR_INVAL,
"unexpected port size");
failure_code = SSH_OPEN_CONNECT_FAILED;
goto x11_exit;
}
_libssh2_debug((session, LIBSSH2_TRACE_CONN,
"X11 Connection Received from %s:%u on channel %u",
x11open_state->shost, x11open_state->sport,
x11open_state->sender_channel));
x11open_state->state = libssh2_NB_state_allocated;
}
if(session->x11) {
if(x11open_state->state == libssh2_NB_state_allocated) {
channel = LIBSSH2_CALLOC(session, sizeof(LIBSSH2_CHANNEL));
if(!channel) {
_libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"allocate a channel for new connection");
failure_code = SSH_OPEN_RESOURCE_SHORTAGE;
goto x11_exit;
}
channel->session = session;
channel->channel_type_len = strlen("x11");
channel->channel_type = LIBSSH2_ALLOC(session,
channel->channel_type_len +
1);
if(!channel->channel_type) {
_libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"allocate a channel for new connection");
LIBSSH2_FREE(session, channel);
failure_code = SSH_OPEN_RESOURCE_SHORTAGE;
goto x11_exit;
}
memcpy(channel->channel_type, "x11",
channel->channel_type_len + 1);
channel->remote.id = x11open_state->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 =
x11open_state->initial_window_size;
channel->local.window_size = x11open_state->initial_window_size;
channel->local.packet_size = x11open_state->packet_size;
_libssh2_debug((session, LIBSSH2_TRACE_CONN,
"X11 Connection established: channel %u/%u "
"win %u/%u packet %u/%u",
channel->local.id, channel->remote.id,
channel->local.window_size,
channel->remote.window_size,
channel->local.packet_size,
channel->remote.packet_size));
p = x11open_state->packet;
*(p++) = SSH_MSG_CHANNEL_OPEN_CONFIRMATION;
_libssh2_store_u32(&p, channel->remote.id);
_libssh2_store_u32(&p, channel->local.id);
_libssh2_store_u32(&p, channel->remote.window_size_initial);
_libssh2_store_u32(&p, channel->remote.packet_size);
x11open_state->state = libssh2_NB_state_created;
}
if(x11open_state->state == libssh2_NB_state_created) {
rc = _libssh2_transport_send(session, x11open_state->packet, 17,
NULL, 0);
if(rc == LIBSSH2_ERROR_EAGAIN) {
return rc;
}
else if(rc) {
x11open_state->state = libssh2_NB_state_idle;
return _libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND,
"Unable to send channel open "
"confirmation");
}
/* Link the channel into the session */
_libssh2_list_add(&session->channels, &channel->node);
/*
* Pass control to the callback, they may turn right around and
* free the channel, or actually use it
*/
LIBSSH2_X11_OPEN(channel, (char *)x11open_state->shost,
x11open_state->sport);
x11open_state->state = libssh2_NB_state_idle;
return 0;
}
}
else
failure_code = SSH_OPEN_RESOURCE_SHORTAGE;
/* fall-trough */
x11_exit:
p = x11open_state->packet;
*(p++) = SSH_MSG_CHANNEL_OPEN_FAILURE;
_libssh2_store_u32(&p, x11open_state->sender_channel);
_libssh2_store_u32(&p, failure_code);
_libssh2_store_str(&p, X11FwdUnAvil, strlen(X11FwdUnAvil));
_libssh2_htonu32(p, 0);
rc = _libssh2_transport_send(session, x11open_state->packet, packet_len,
NULL, 0);
if(rc == LIBSSH2_ERROR_EAGAIN) {
return rc;
}
else if(rc) {
x11open_state->state = libssh2_NB_state_idle;
return _libssh2_error(session, rc, "Unable to send open failure");
}
x11open_state->state = libssh2_NB_state_idle;
return 0;
}
/*
* packet_authagent_open
*
* Open a connection to authentication agent
*/
static inline int
packet_authagent_open(LIBSSH2_SESSION * session,
unsigned char *data, size_t datalen,
packet_authagent_state_t *authagent_state)
{
int failure_code = SSH_OPEN_CONNECT_FAILED;
/* 17 = packet_type(1) + channel(4) + reason(4) + descr(4) + lang(4) */
size_t packet_len = 17 + strlen(X11FwdUnAvil);
unsigned char *p;
LIBSSH2_CHANNEL *channel = authagent_state->channel;
int rc;
struct string_buf buf;
size_t offset = strlen("auth-agent@openssh.org") + 5;
buf.data = data;
buf.dataptr = buf.data;
buf.len = datalen;
buf.dataptr += offset;
if(datalen < offset) {
return _libssh2_error(session, LIBSSH2_ERROR_OUT_OF_BOUNDARY,
"Unexpected packet size");
}
if(authagent_state->state == libssh2_NB_state_idle) {
if(_libssh2_get_u32(&buf, &(authagent_state->sender_channel))) {
return _libssh2_error(session, LIBSSH2_ERROR_BUFFER_TOO_SMALL,
"Data too short extracting channel");
}
if(_libssh2_get_u32(&buf, &(authagent_state->initial_window_size))) {
return _libssh2_error(session, LIBSSH2_ERROR_BUFFER_TOO_SMALL,
"Data too short extracting window size");
}
if(_libssh2_get_u32(&buf, &(authagent_state->packet_size))) {
return _libssh2_error(session, LIBSSH2_ERROR_BUFFER_TOO_SMALL,
"Data too short extracting packet");
}
_libssh2_debug((session, LIBSSH2_TRACE_CONN,
"Auth Agent Connection Received on channel %u",
authagent_state->sender_channel));
authagent_state->state = libssh2_NB_state_allocated;
}
if(session->authagent) {
if(authagent_state->state == libssh2_NB_state_allocated) {
channel = LIBSSH2_ALLOC(session, sizeof(LIBSSH2_CHANNEL));
authagent_state->channel = channel;
if(!channel) {
_libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"allocate a channel for new connection");
failure_code = SSH_OPEN_RESOURCE_SHORTAGE;
goto authagent_exit;
}
memset(channel, 0, sizeof(LIBSSH2_CHANNEL));
channel->session = session;
channel->channel_type_len = strlen("auth agent");
channel->channel_type = LIBSSH2_ALLOC(session,
channel->channel_type_len +
1);
if(!channel->channel_type) {
_libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"allocate a channel for new connection");
LIBSSH2_FREE(session, channel);
failure_code = SSH_OPEN_RESOURCE_SHORTAGE;
goto authagent_exit;
}
memcpy(channel->channel_type, "auth agent",
channel->channel_type_len + 1);
channel->remote.id = authagent_state->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 =
authagent_state->initial_window_size;
channel->local.window_size = authagent_state->initial_window_size;
channel->local.packet_size = authagent_state->packet_size;
_libssh2_debug((session, LIBSSH2_TRACE_CONN,
"Auth Agent Connection established: channel "
"%u/%u win %u/%u packet %u/%u",
channel->local.id, channel->remote.id,
channel->local.window_size,
channel->remote.window_size,
channel->local.packet_size,
channel->remote.packet_size));
p = authagent_state->packet;
*(p++) = SSH_MSG_CHANNEL_OPEN_CONFIRMATION;
_libssh2_store_u32(&p, channel->remote.id);
_libssh2_store_u32(&p, channel->local.id);
_libssh2_store_u32(&p, channel->remote.window_size_initial);
_libssh2_store_u32(&p, channel->remote.packet_size);
authagent_state->state = libssh2_NB_state_created;
}
if(authagent_state->state == libssh2_NB_state_created) {
rc = _libssh2_transport_send(session, authagent_state->packet, 17,
NULL, 0);
if(rc == LIBSSH2_ERROR_EAGAIN) {
return rc;
}
else if(rc) {
authagent_state->state = libssh2_NB_state_idle;
return _libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND,
"Unable to send channel open "
"confirmation");
}
/* Link the channel into the session */
_libssh2_list_add(&session->channels, &channel->node);
/* mess with stuff so we don't keep reading the same packet
over and over */
session->packet.total_num = 0;
session->fullpacket_state = libssh2_NB_state_idle;
/* Pass control to the callback, they may turn right around and
and free the channel, or actually use it */
LIBSSH2_AUTHAGENT(channel);
authagent_state->state = libssh2_NB_state_idle;
return 0;
}
}
else
failure_code = SSH_OPEN_RESOURCE_SHORTAGE;
/* fall-through */
authagent_exit:
p = authagent_state->packet;
*(p++) = SSH_MSG_CHANNEL_OPEN_FAILURE;
_libssh2_store_u32(&p, authagent_state->sender_channel);
_libssh2_store_u32(&p, failure_code);
_libssh2_store_str(&p, AuthAgentUnavail, strlen(AuthAgentUnavail));
_libssh2_htonu32(p, 0);
rc = _libssh2_transport_send(session, authagent_state->packet, packet_len,
NULL, 0);
if(rc == LIBSSH2_ERROR_EAGAIN) {
return rc;
}
else if(rc) {
authagent_state->state = libssh2_NB_state_idle;
return _libssh2_error(session, rc, "Unable to send open failure");
}
authagent_state->state = libssh2_NB_state_idle;
return 0;
}
/*
* _libssh2_packet_add
*
* Create a new packet and attach it to the brigade. Called from the transport
* layer when it has received a packet.
*
* The input pointer 'data' is pointing to allocated data that this function
* will be freed unless return the code is LIBSSH2_ERROR_EAGAIN.
*
* This function will always be called with 'datalen' greater than zero.
*/
int
_libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
size_t datalen, int macstate, uint32_t seq)
{
int rc = 0;
unsigned char *message = NULL;
unsigned char *language = NULL;
size_t message_len = 0;
size_t language_len = 0;
LIBSSH2_CHANNEL *channelp = NULL;
size_t data_head = 0;
unsigned char msg = data[0];
uint32_t channel = 0;
uint32_t len = 0;
unsigned char want_reply = 0;
switch(session->packAdd_state) {
case libssh2_NB_state_idle:
_libssh2_debug((session, LIBSSH2_TRACE_TRANS,
"Packet type %u received, length=%ld",
(unsigned int) msg, (long) datalen));
if((macstate == LIBSSH2_MAC_INVALID) &&
(!session->macerror ||
LIBSSH2_MACERROR(session, (char *) data, datalen))) {
/* Bad MAC input, but no callback set or non-zero return from the
callback */
LIBSSH2_FREE(session, data);
return _libssh2_error(session, LIBSSH2_ERROR_INVALID_MAC,
"Invalid MAC received");
}
session->packAdd_state = libssh2_NB_state_allocated;
break;
case libssh2_NB_state_jump1:
goto libssh2_packet_add_jump_point1;
case libssh2_NB_state_jump2:
goto libssh2_packet_add_jump_point2;
case libssh2_NB_state_jump3:
goto libssh2_packet_add_jump_point3;
case libssh2_NB_state_jump4:
goto libssh2_packet_add_jump_point4;
case libssh2_NB_state_jump5:
goto libssh2_packet_add_jump_point5;
case libssh2_NB_state_jumpauthagent:
goto libssh2_packet_add_jump_authagent;
default: /* nothing to do */
break;
}
if(session->state & LIBSSH2_STATE_INITIAL_KEX) {
if(msg == SSH_MSG_KEXINIT) {
if(!session->kex_strict) {
if(datalen < 17) {
LIBSSH2_FREE(session, data);
session->packAdd_state = libssh2_NB_state_idle;
return _libssh2_error(session,
LIBSSH2_ERROR_BUFFER_TOO_SMALL,
"Data too short extracting kex");
}
else {
const unsigned char *strict =
(const unsigned char *)"kex-strict-s-v00@openssh.com";
struct string_buf buf;
unsigned char *algs = NULL;
size_t algs_len = 0;
buf.data = (unsigned char *)data;
buf.dataptr = buf.data;
buf.len = datalen;
buf.dataptr += 17; /* advance past type and cookie */
if(_libssh2_get_string(&buf, &algs, &algs_len)) {
LIBSSH2_FREE(session, data);
session->packAdd_state = libssh2_NB_state_idle;
return _libssh2_error(session,
LIBSSH2_ERROR_BUFFER_TOO_SMALL,
"Algs too short");
}
if(algs_len == 0 ||
_libssh2_kex_agree_instr(algs, algs_len, strict, 28)) {
session->kex_strict = 1;
}
}
}
if(session->kex_strict && seq) {
LIBSSH2_FREE(session, data);
session->socket_state = LIBSSH2_SOCKET_DISCONNECTED;
session->packAdd_state = libssh2_NB_state_idle;
libssh2_session_disconnect(session, "strict KEX violation: "
"KEXINIT was not the first packet");
return _libssh2_error(session, LIBSSH2_ERROR_SOCKET_DISCONNECT,
"strict KEX violation: "
"KEXINIT was not the first packet");
}
}
if(session->kex_strict && session->fullpacket_required_type &&
session->fullpacket_required_type != msg) {
LIBSSH2_FREE(session, data);
session->socket_state = LIBSSH2_SOCKET_DISCONNECTED;
session->packAdd_state = libssh2_NB_state_idle;
libssh2_session_disconnect(session, "strict KEX violation: "
"unexpected packet type");
return _libssh2_error(session, LIBSSH2_ERROR_SOCKET_DISCONNECT,
"strict KEX violation: "
"unexpected packet type");
}
}
if(session->packAdd_state == libssh2_NB_state_allocated) {
/* A couple exceptions to the packet adding rule: */
switch(msg) {
/*
byte SSH_MSG_DISCONNECT
uint32 reason code
string description in ISO-10646 UTF-8 encoding [RFC3629]
string language tag [RFC3066]
*/
case SSH_MSG_DISCONNECT:
if(datalen >= 5) {
uint32_t reason = 0;
struct string_buf buf;
buf.data = (unsigned char *)data;
buf.dataptr = buf.data;
buf.len = datalen;
buf.dataptr++; /* advance past type */
_libssh2_get_u32(&buf, &reason);
_libssh2_get_string(&buf, &message, &message_len);
_libssh2_get_string(&buf, &language, &language_len);
if(session->ssh_msg_disconnect) {
LIBSSH2_DISCONNECT(session, reason, (const char *)message,
message_len, (const char *)language,
language_len);
}
_libssh2_debug((session, LIBSSH2_TRACE_TRANS,
"Disconnect(%d): %s(%s)", reason,
message, language));
}
LIBSSH2_FREE(session, data);
session->socket_state = LIBSSH2_SOCKET_DISCONNECTED;
session->packAdd_state = libssh2_NB_state_idle;
return _libssh2_error(session, LIBSSH2_ERROR_SOCKET_DISCONNECT,
"socket disconnect");
/*
byte SSH_MSG_IGNORE
string data
*/
case SSH_MSG_IGNORE:
if(datalen >= 2) {
if(session->ssh_msg_ignore) {
LIBSSH2_IGNORE(session, (char *) data + 1, datalen - 1);
}
}
else if(session->ssh_msg_ignore) {
LIBSSH2_IGNORE(session, "", 0);
}
LIBSSH2_FREE(session, data);
session->packAdd_state = libssh2_NB_state_idle;
return 0;
/*
byte SSH_MSG_DEBUG
boolean always_display
string message in ISO-10646 UTF-8 encoding [RFC3629]
string language tag [RFC3066]
*/
case SSH_MSG_DEBUG:
if(datalen >= 2) {
int always_display = data[1];
if(datalen >= 6) {
struct string_buf buf;
buf.data = (unsigned char *)data;
buf.dataptr = buf.data;
buf.len = datalen;
buf.dataptr += 2; /* advance past type & always display */
_libssh2_get_string(&buf, &message, &message_len);
_libssh2_get_string(&buf, &language, &language_len);
}
if(session->ssh_msg_debug) {
LIBSSH2_DEBUG(session, always_display,
(const char *)message,
message_len, (const char *)language,
language_len);
}
}
/*
* _libssh2_debug() will actually truncate this for us so
* that it's not an inordinate about of data
*/
_libssh2_debug((session, LIBSSH2_TRACE_TRANS,
"Debug Packet: %s", message));
LIBSSH2_FREE(session, data);
session->packAdd_state = libssh2_NB_state_idle;
return 0;
/*
byte SSH_MSG_EXT_INFO
uint32 nr-extensions
[repeat "nr-extensions" times]
string extension-name [RFC8308]
string extension-value (binary)
*/
case SSH_MSG_EXT_INFO:
if(datalen >= 5) {
uint32_t nr_extensions = 0;
struct string_buf buf;
buf.data = (unsigned char *)data;
buf.dataptr = buf.data;
buf.len = datalen;
buf.dataptr += 1; /* advance past type */
if(_libssh2_get_u32(&buf, &nr_extensions) != 0) {
rc = _libssh2_error(session, LIBSSH2_ERROR_PROTO,
"Invalid extension info received");
}
while(rc == 0 && nr_extensions > 0) {
size_t name_len = 0;
size_t value_len = 0;
unsigned char *name = NULL;
unsigned char *value = NULL;
nr_extensions -= 1;
_libssh2_get_string(&buf, &name, &name_len);
_libssh2_get_string(&buf, &value, &value_len);
if(name && value) {
_libssh2_debug((session,
LIBSSH2_TRACE_KEX,
"Server to Client extension %.*s: %.*s",
(int)name_len, name,
(int)value_len, value));
}
if(name && name_len == 15 &&
memcmp(name, "server-sig-algs", 15) == 0) {
if(session->server_sign_algorithms) {
LIBSSH2_FREE(session,
session->server_sign_algorithms);
}
session->server_sign_algorithms =
LIBSSH2_ALLOC(session,
value_len + 1);
if(value && session->server_sign_algorithms) {
memcpy(session->server_sign_algorithms,
value, value_len);
session->server_sign_algorithms[value_len] = '\0';
}
else {
rc = _libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"memory for server sign algo");
}
}
}
}
LIBSSH2_FREE(session, data);
session->packAdd_state = libssh2_NB_state_idle;
return rc;
/*
byte SSH_MSG_GLOBAL_REQUEST
string request name in US-ASCII only
boolean want reply
.... request-specific data follows
*/
case SSH_MSG_GLOBAL_REQUEST:
if(datalen >= 5) {
want_reply = 0;
len = _libssh2_ntohu32(data + 1);
if((len <= (UINT_MAX - 6)) && (datalen >= (6 + len))) {
want_reply = data[5 + len];
_libssh2_debug((session,
LIBSSH2_TRACE_CONN,
"Received global request type %.*s (wr %X)",
(int)len, data + 5, want_reply));
}
if(want_reply) {
static const unsigned char packet =
SSH_MSG_REQUEST_FAILURE;
libssh2_packet_add_jump_point5:
session->packAdd_state = libssh2_NB_state_jump5;
rc = _libssh2_transport_send(session, &packet, 1, NULL, 0);
if(rc == LIBSSH2_ERROR_EAGAIN)
return rc;
}
}
LIBSSH2_FREE(session, data);
session->packAdd_state = libssh2_NB_state_idle;
return 0;
/*
byte SSH_MSG_CHANNEL_EXTENDED_DATA
uint32 recipient channel
uint32 data_type_code
string data
*/
case SSH_MSG_CHANNEL_EXTENDED_DATA:
/* streamid(4) */
data_head += 4;
LIBSSH2_FALLTHROUGH();
/*
byte SSH_MSG_CHANNEL_DATA
uint32 recipient channel
string data
*/
case SSH_MSG_CHANNEL_DATA:
/* packet_type(1) + channelno(4) + datalen(4) */
data_head += 9;
if(datalen >= data_head)
channelp =
_libssh2_channel_locate(session,
_libssh2_ntohu32(data + 1));
if(!channelp) {
_libssh2_error(session, LIBSSH2_ERROR_CHANNEL_UNKNOWN,
"Packet received for unknown channel");
LIBSSH2_FREE(session, data);
session->packAdd_state = libssh2_NB_state_idle;
return 0;
}
#ifdef LIBSSH2DEBUG
{
uint32_t stream_id = 0;
if(msg == SSH_MSG_CHANNEL_EXTENDED_DATA)
stream_id = _libssh2_ntohu32(data + 5);
_libssh2_debug((session, LIBSSH2_TRACE_CONN,
"%ld bytes packet_add() for %u/%u/%u",
(long) (datalen - data_head),
channelp->local.id,
channelp->remote.id,
stream_id));
}
#endif
if((channelp->remote.extended_data_ignore_mode ==
LIBSSH2_CHANNEL_EXTENDED_DATA_IGNORE) &&
(msg == SSH_MSG_CHANNEL_EXTENDED_DATA)) {
/* Pretend we didn't receive this */