Initial revision
This commit is contained in:
Sara Golemon
372
src/session.c
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372
src/session.c
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/* Copyright (c) 2004, Sara Golemon <sarag@users.sourceforge.net>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms,
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* with or without modification, are permitted provided
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* that the following conditions are met:
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*
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* Redistributions of source code must retain the above
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* copyright notice, this list of conditions and the
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* following disclaimer.
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*
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* Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials
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* provided with the distribution.
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*
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* Neither the name of the copyright holder nor the names
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* of any other contributors may be used to endorse or
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* promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
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* USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*/
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#include "libssh2_priv.h"
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#include <errno.h>
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#include <unistd.h>
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#include <stdlib.h>
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/* {{{ libssh2_default_alloc
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*/
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static LIBSSH2_ALLOC_FUNC(libssh2_default_alloc)
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{
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return malloc(count);
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}
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/* }}} */
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/* {{{ libssh2_default_free
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*/
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static LIBSSH2_FREE_FUNC(libssh2_default_free)
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{
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free(ptr);
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}
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/* }}} */
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/* {{{ libssh2_default_realloc
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*/
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static LIBSSH2_REALLOC_FUNC(libssh2_default_realloc)
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{
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return realloc(ptr, count);
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}
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/* }}} */
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/* {{{ libssh2_banner_receive
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* Wait for a hello from the remote host
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* Allocate a buffer and store the banner in session->remote.banner
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* Returns: 0 on success, 1 on failure
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*/
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static int libssh2_banner_receive(LIBSSH2_SESSION *session)
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{
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char banner[256];
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int banner_len = 0;
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while ((banner_len < sizeof(banner)) &&
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((banner_len == 0) || (banner[banner_len-1] != '\n'))) {
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char c = '\0';
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int ret;
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ret = read(session->socket_fd, &c, 1);
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if ((ret < 0) && (ret != EAGAIN)) {
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/* Some kinda error, but don't break for non-blocking issues */
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return 1;
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}
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if (ret <= 0) continue;
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if (c == '\0') {
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/* NULLs are not allowed in SSH banners */
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return 1;
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}
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banner[banner_len++] = c;
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}
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while (banner_len &&
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((banner[banner_len-1] == '\n') || (banner[banner_len-1] == '\r'))) {
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banner_len--;
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}
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if (!banner_len) return 1;
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session->remote.banner = LIBSSH2_ALLOC(session, banner_len + 1);
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memcpy(session->remote.banner, banner, banner_len);
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session->remote.banner[banner_len] = '\0';
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return 0;
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}
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/* }}} */
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/* {{{ libssh2_banner_send
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* Send the default banner, or the one set via libssh2_setopt_string
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*/
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static int libssh2_banner_send(LIBSSH2_SESSION *session)
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{
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char *banner = LIBSSH2_SSH_DEFAULT_BANNER_WITH_CRLF;
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int banner_len = sizeof(LIBSSH2_SSH_DEFAULT_BANNER_WITH_CRLF) - 1;
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if (session->local.banner) {
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/* setopt_string will have given us our \r\n characters */
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banner_len = strlen(session->local.banner);
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banner = session->local.banner;
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}
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return (write(session->socket_fd, banner, banner_len) == banner_len) ? 0 : 1;
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}
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/* }}} */
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/* {{{ proto libssh2_session_init
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* Allocate and initialize a libssh2 session structure
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* Allows for malloc callbacks in case the calling program has its own memory manager
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* It's allowable (but unadvisable) to define some but not all of the malloc callbacks
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* An additional pointer value may be optionally passed to be sent to the callbacks (so they know who's asking)
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*/
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LIBSSH2_API LIBSSH2_SESSION *libssh2_session_init_ex(
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LIBSSH2_ALLOC_FUNC((*my_alloc)),
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LIBSSH2_FREE_FUNC((*my_free)),
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LIBSSH2_REALLOC_FUNC((*my_realloc)),
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void *abstract)
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{
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LIBSSH2_ALLOC_FUNC((*local_alloc)) = libssh2_default_alloc;
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LIBSSH2_FREE_FUNC((*local_free)) = libssh2_default_free;
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LIBSSH2_REALLOC_FUNC((*local_realloc)) = libssh2_default_realloc;
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LIBSSH2_SESSION *session;
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if (my_alloc) local_alloc = my_alloc;
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if (my_free) local_free = my_free;
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if (my_realloc) local_realloc = my_realloc;
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session = local_alloc(sizeof(LIBSSH2_SESSION), abstract);
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memset(session, 0, sizeof(LIBSSH2_SESSION));
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session->alloc = local_alloc;
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session->free = local_free;
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session->realloc = local_realloc;
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session->abstract = abstract;
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return session;
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}
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/* }}} */
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/* {{{ proto libssh2_session_startup
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* session: LIBSSH2_SESSION struct allocated and owned by the calling program
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* Returns: 0 on success, or non-zero on failure
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* Any memory allocated by libssh2 will use alloc/realloc/free callbacks in session
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* socket *must* be populated with an opened socket
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*/
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LIBSSH2_API int libssh2_session_startup(LIBSSH2_SESSION *session, int socket)
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{
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unsigned char *data;
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unsigned long data_len;
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unsigned char service[sizeof("ssh-userauth") + 5 - 1];
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unsigned long service_length;
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if (socket <= 0) {
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/* Did we forget something? */
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libssh2_error(session, LIBSSH2_ERROR_SOCKET_NONE, "No socket provided", 0);
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return LIBSSH2_ERROR_SOCKET_NONE;
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}
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session->socket_fd = socket;
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/* TODO: Liveness check */
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if (libssh2_banner_receive(session)) {
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/* Unable to receive banner from remote */
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libssh2_error(session, LIBSSH2_ERROR_BANNER_NONE, "Timeout waiting for banner", 0);
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return LIBSSH2_ERROR_BANNER_NONE;
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}
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if (libssh2_banner_send(session)) {
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/* Unable to send banner? */
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libssh2_error(session, LIBSSH2_ERROR_BANNER_SEND, "Error sending banner to remote host", 0);
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return LIBSSH2_ERROR_BANNER_SEND;
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}
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if (libssh2_kex_exchange(session, 0)) {
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libssh2_error(session, LIBSSH2_ERROR_KEX_FAILURE, "Unable to exchange encryption keys", 0);
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return LIBSSH2_ERROR_KEX_FAILURE;
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}
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/* Request the userauth service */
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service[0] = SSH_MSG_SERVICE_REQUEST;
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libssh2_htonu32(service + 1, sizeof("ssh-userauth") - 1);
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memcpy(service + 5, "ssh-userauth", sizeof("ssh-userauth") - 1);
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if (libssh2_packet_write(session, service, sizeof("ssh-userauth") + 5 - 1)) {
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libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND, "Unable to ask for ssh-userauth service", 0);
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return LIBSSH2_ERROR_SOCKET_SEND;
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}
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if (libssh2_packet_require(session, SSH_MSG_SERVICE_ACCEPT, &data, &data_len)) {
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return LIBSSH2_ERROR_SOCKET_DISCONNECT;
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}
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service_length = libssh2_ntohu32(data + 1);
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if ((service_length != (sizeof("ssh-userauth") - 1)) ||
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strncmp("ssh-userauth", data + 5, service_length)) {
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LIBSSH2_FREE(session, data);
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libssh2_error(session, LIBSSH2_ERROR_PROTO, "Invalid response received from server", 0);
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return LIBSSH2_ERROR_PROTO;
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}
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LIBSSH2_FREE(session, data);
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return 0;
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}
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/* }}} */
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/* {{{ proto libssh2_session_free
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* Frees the memory allocated to the session
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* Also closes and frees any channels attached to this session
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*/
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LIBSSH2_API void libssh2_session_free(LIBSSH2_SESSION *session)
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{
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while (session->channels.head) {
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LIBSSH2_CHANNEL *tmp = session->channels.head;
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libssh2_channel_free(session->channels.head);
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if (tmp == session->channels.head) {
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/* channel_free couldn't do it's job, perform a messy cleanup */
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tmp = session->channels.head;
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/* unlink */
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session->channels.head = tmp->next;
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/* free */
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LIBSSH2_FREE(session, tmp);
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/* reverse linking isn't important here, we're killing the structure */
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}
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}
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if (session->newkeys) {
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/* hostkey */
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if (session->hostkey && session->hostkey->dtor) {
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session->hostkey->dtor(session, &session->server_hostkey_abstract);
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}
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/* Client to Server */
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/* crypt */
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if (session->local.crypt) {
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if (session->local.crypt->flags & LIBSSH2_CRYPT_METHOD_FLAG_EVP) {
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if (session->local.crypt_abstract) {
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LIBSSH2_FREE(session, session->local.crypt_abstract);
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session->local.crypt_abstract = NULL;
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}
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} else if (session->local.crypt->dtor) {
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session->local.crypt->dtor(session, &session->local.crypt_abstract);
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}
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}
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/* comp */
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if (session->local.comp && session->local.comp->dtor) {
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session->local.comp->dtor(session, 1, &session->local.comp_abstract);
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}
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/* mac */
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if (session->local.mac && session->local.mac->dtor) {
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session->local.mac->dtor(session, &session->local.mac_abstract);
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}
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/* Server to Client */
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/* crypt */
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if (session->remote.crypt) {
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if (session->remote.crypt->flags & LIBSSH2_CRYPT_METHOD_FLAG_EVP) {
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if (session->remote.crypt_abstract) {
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LIBSSH2_FREE(session, session->remote.crypt_abstract);
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session->remote.crypt_abstract = NULL;
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}
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} else if (session->remote.crypt->dtor) {
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session->remote.crypt->dtor(session, &session->remote.crypt_abstract);
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}
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}
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/* comp */
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if (session->remote.comp && session->remote.comp->dtor) {
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session->remote.comp->dtor(session, 0, &session->remote.comp_abstract);
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}
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/* mac */
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if (session->remote.mac && session->remote.mac->dtor) {
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session->remote.mac->dtor(session, &session->remote.mac_abstract);
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}
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/* session_id */
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if (session->session_id) {
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LIBSSH2_FREE(session, session->session_id);
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}
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}
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if (session->remote.banner) {
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LIBSSH2_FREE(session, session->remote.banner);
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}
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if (session->local.banner) {
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LIBSSH2_FREE(session, session->local.banner);
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}
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/* Cleanup any remaining packets */
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while (session->packets.head) {
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LIBSSH2_PACKET *tmp = session->packets.head;
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/* unlink */
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session->packets.head = tmp->next;
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/* free */
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LIBSSH2_FREE(session, tmp->data);
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LIBSSH2_FREE(session, tmp);
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}
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if (session->local.banner) {
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LIBSSH2_FREE(session, session->local.banner);
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}
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LIBSSH2_FREE(session, session);
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}
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/* }}} */
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/* {{{ libssh2_session_disconnect_ex
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*/
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LIBSSH2_API void libssh2_session_disconnect_ex(LIBSSH2_SESSION *session, int reason, char *description, char *lang)
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{
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unsigned char *data;
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unsigned long data_len, descr_len = 0, lang_len = 0;
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if (description) {
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descr_len = strlen(description);
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}
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if (lang) {
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lang_len = strlen(lang);
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}
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data_len = descr_len + lang_len + 13; /* packet_type(1) + reason code(4) + descr_len(4) + lang_len(4) */
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data = LIBSSH2_ALLOC(session, data_len);
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if (data) {
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unsigned char *s = data;
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*(s++) = SSH_MSG_DISCONNECT;
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libssh2_htonu32(s, reason); s += 4;
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libssh2_htonu32(s, descr_len); s += 4;
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if (description) {
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memcpy(s, description, descr_len);
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s += descr_len;
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}
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libssh2_htonu32(s, lang_len); s += 4;
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if (lang) {
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memcpy(s, lang, lang_len);
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s += lang_len;
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}
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libssh2_packet_write(session, data, data_len);
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LIBSSH2_FREE(session, data);
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}
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}
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/* }}} */
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