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e0e3636c60dd28fd358e47da2be132702ff8edc9
libssh/src/server.c
Jakub Jelen ab24d64241 Use only one variable denoting the size of methods arrays 
Previously, there was non-consistent usage of constans SSH_KEX_METHODS,
KEX_METHODS_SIZE and of magic number 10 to reference the arrays used
for algorithm negotiation by peers. This commit settles down to the single
constant and its usage throughout the whole codebase.

Fixes T195

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
(cherry picked from commit c8a621c606)
2019-12-09 16:38:36 +01:00

1168 lines
34 KiB
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/*
* server.c - functions for creating a SSH server
*
* This file is part of the SSH Library
*
* Copyright (c) 2004-2013 by Aris Adamantiadis
*
* The SSH Library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at your
* option) any later version.
*
* The SSH Library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with the SSH Library; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA.
*/
#include "config.h"
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#ifdef _WIN32
# include <winsock2.h>
# include <ws2tcpip.h>
/*
* <wspiapi.h> is necessary for getaddrinfo before Windows XP, but it isn't
* available on some platforms like MinGW.
*/
# ifdef HAVE_WSPIAPI_H
# include <wspiapi.h>
# endif
#else
# include <netinet/in.h>
#endif
#include "libssh/priv.h"
#include "libssh/libssh.h"
#include "libssh/server.h"
#include "libssh/ssh2.h"
#include "libssh/buffer.h"
#include "libssh/packet.h"
#include "libssh/socket.h"
#include "libssh/session.h"
#include "libssh/kex.h"
#include "libssh/misc.h"
#include "libssh/pki.h"
#include "libssh/dh.h"
#include "libssh/messages.h"
#include "libssh/options.h"
#include "libssh/curve25519.h"
#include "libssh/token.h"
#define set_status(session, status) do {\
if (session->common.callbacks && session->common.callbacks->connect_status_function) \
session->common.callbacks->connect_status_function(session->common.callbacks->userdata, status); \
} while (0)
/**
* @addtogroup libssh_server
*
* @{
*/
/** @internal
*
* @brief initialize the set of key exchange, hostkey, ciphers, MACs, and
* compression algorithms for the given ssh_session
*
* The selection of algorithms and keys used are determined by the
* options that are currently set in the given ssh_session structure.
*/
int server_set_kex(ssh_session session)
{
struct ssh_kex_struct *server = &session->next_crypto->server_kex;
int i, j, rc;
const char *wanted, *allowed;
char *kept;
char hostkeys[128] = {0};
enum ssh_keytypes_e keytype;
size_t len;
int ok;
ZERO_STRUCTP(server);
ok = ssh_get_random(server->cookie, 16, 0);
if (!ok) {
ssh_set_error(session, SSH_FATAL, "PRNG error");
return -1;
}
if (session->srv.ed25519_key != NULL) {
snprintf(hostkeys,
sizeof(hostkeys),
"%s",
ssh_key_type_to_char(ssh_key_type(session->srv.ed25519_key)));
}
#ifdef HAVE_ECC
if (session->srv.ecdsa_key != NULL) {
len = strlen(hostkeys);
snprintf(hostkeys + len, sizeof(hostkeys) - len,
",%s", session->srv.ecdsa_key->type_c);
}
#endif
#ifdef HAVE_DSA
if (session->srv.dsa_key != NULL) {
len = strlen(hostkeys);
keytype = ssh_key_type(session->srv.dsa_key);
snprintf(hostkeys + len, sizeof(hostkeys) - len,
",%s", ssh_key_type_to_char(keytype));
}
#endif
if (session->srv.rsa_key != NULL) {
/* We support also the SHA2 variants */
len = strlen(hostkeys);
snprintf(hostkeys + len, sizeof(hostkeys) - len,
",rsa-sha2-512,rsa-sha2-256");
len = strlen(hostkeys);
keytype = ssh_key_type(session->srv.rsa_key);
snprintf(hostkeys + len, sizeof(hostkeys) - len,
",%s", ssh_key_type_to_char(keytype));
}
if (strlen(hostkeys) == 0) {
return -1;
}
if (session->opts.wanted_methods[SSH_HOSTKEYS]) {
allowed = session->opts.wanted_methods[SSH_HOSTKEYS];
} else {
if (ssh_fips_mode()) {
allowed = ssh_kex_get_fips_methods(SSH_HOSTKEYS);
} else {
allowed = ssh_kex_get_default_methods(SSH_HOSTKEYS);
}
}
/* It is expected for the list of allowed hostkeys to be ordered by
* preference */
kept = ssh_find_all_matching(hostkeys[0] == ',' ? hostkeys + 1 : hostkeys,
allowed);
if (kept == NULL) {
/* Nothing was allowed */
return -1;
}
rc = ssh_options_set_algo(session,
SSH_HOSTKEYS,
kept);
SAFE_FREE(kept);
if (rc < 0) {
return -1;
}
for (i = 0; i < SSH_KEX_METHODS; i++) {
wanted = session->opts.wanted_methods[i];
if (wanted == NULL) {
if (ssh_fips_mode()) {
wanted = ssh_kex_get_fips_methods(i);
} else {
wanted = ssh_kex_get_default_methods(i);
}
}
server->methods[i] = strdup(wanted);
if (server->methods[i] == NULL) {
for (j = 0; j < i; j++) {
SAFE_FREE(server->methods[j]);
}
return -1;
}
}
return 0;
}
int ssh_server_init_kex(ssh_session session) {
int i;
if (session->session_state > SSH_SESSION_STATE_BANNER_RECEIVED) {
return SSH_ERROR;
}
/* free any currently-set methods: server_set_kex will allocate new ones */
for (i = 0; i < SSH_KEX_METHODS; i++) {
SAFE_FREE(session->next_crypto->server_kex.methods[i]);
}
return server_set_kex(session);
}
static int ssh_server_send_extensions(ssh_session session) {
int rc;
const char *hostkey_algorithms;
SSH_LOG(SSH_LOG_PACKET, "Sending SSH_MSG_EXT_INFO");
if (session->opts.pubkey_accepted_types) {
hostkey_algorithms = session->opts.pubkey_accepted_types;
} else {
if (ssh_fips_mode()) {
hostkey_algorithms = ssh_kex_get_fips_methods(SSH_HOSTKEYS);
} else {
/* There are no restrictions to the accepted public keys */
hostkey_algorithms = ssh_kex_get_default_methods(SSH_HOSTKEYS);
}
}
rc = ssh_buffer_pack(session->out_buffer,
"bdss",
SSH2_MSG_EXT_INFO,
1, /* nr. of extensions */
"server-sig-algs",
hostkey_algorithms);
if (rc != SSH_OK) {
goto error;
}
if (ssh_packet_send(session) == SSH_ERROR) {
goto error;
}
return 0;
error:
ssh_buffer_reinit(session->out_buffer);
return -1;
}
SSH_PACKET_CALLBACK(ssh_packet_kexdh_init){
(void)packet;
(void)type;
(void)user;
SSH_LOG(SSH_LOG_PACKET,"Received SSH_MSG_KEXDH_INIT");
if(session->dh_handshake_state != DH_STATE_INIT){
SSH_LOG(SSH_LOG_RARE,"Invalid state for SSH_MSG_KEXDH_INIT");
session->session_state = SSH_SESSION_STATE_ERROR;
return SSH_PACKET_USED;
}
/* If first_kex_packet_follows guess was wrong, ignore this message. */
if (session->first_kex_follows_guess_wrong != 0) {
SSH_LOG(SSH_LOG_RARE, "first_kex_packet_follows guess was wrong, "
"ignoring first SSH_MSG_KEXDH_INIT message");
session->first_kex_follows_guess_wrong = 0;
return SSH_PACKET_USED;
}
SSH_LOG(SSH_LOG_DEBUG, "Calling next KEXDH handler");
return SSH_PACKET_NOT_USED;
}
int
ssh_get_key_params(ssh_session session,
ssh_key *privkey,
enum ssh_digest_e *digest)
{
ssh_key pubkey;
ssh_string pubkey_blob;
int rc;
switch(session->srv.hostkey) {
case SSH_KEYTYPE_DSS:
*privkey = session->srv.dsa_key;
break;
case SSH_KEYTYPE_RSA:
*privkey = session->srv.rsa_key;
break;
case SSH_KEYTYPE_ECDSA_P256:
case SSH_KEYTYPE_ECDSA_P384:
case SSH_KEYTYPE_ECDSA_P521:
*privkey = session->srv.ecdsa_key;
break;
case SSH_KEYTYPE_ED25519:
*privkey = session->srv.ed25519_key;
break;
case SSH_KEYTYPE_RSA1:
case SSH_KEYTYPE_UNKNOWN:
default:
*privkey = NULL;
}
*digest = session->srv.hostkey_digest;
rc = ssh_pki_export_privkey_to_pubkey(*privkey, &pubkey);
if (rc < 0) {
ssh_set_error(session, SSH_FATAL,
"Could not get the public key from the private key");
return -1;
}
rc = ssh_pki_export_pubkey_blob(pubkey, &pubkey_blob);
ssh_key_free(pubkey);
if (rc < 0) {
ssh_set_error_oom(session);
return -1;
}
rc = ssh_dh_import_next_pubkey_blob(session, pubkey_blob);
ssh_string_free(pubkey_blob);
if (rc != 0) {
ssh_set_error(session,
SSH_FATAL,
"Could not import server public key");
return -1;
}
return SSH_OK;
}
/**
* @internal
*
* @brief A function to be called each time a step has been done in the
* connection.
*/
static void ssh_server_connection_callback(ssh_session session){
int rc;
switch(session->session_state){
case SSH_SESSION_STATE_NONE:
case SSH_SESSION_STATE_CONNECTING:
case SSH_SESSION_STATE_SOCKET_CONNECTED:
break;
case SSH_SESSION_STATE_BANNER_RECEIVED:
if (session->clientbanner == NULL) {
goto error;
}
set_status(session, 0.4f);
SSH_LOG(SSH_LOG_PROTOCOL,
"SSH client banner: %s", session->clientbanner);
/* Here we analyze the different protocols the server allows. */
rc = ssh_analyze_banner(session, 1);
if (rc < 0) {
ssh_set_error(session, SSH_FATAL,
"No version of SSH protocol usable (banner: %s)",
session->clientbanner);
goto error;
}
/* from now, the packet layer is handling incoming packets */
session->socket_callbacks.data=ssh_packet_socket_callback;
ssh_packet_register_socket_callback(session, session->socket);
ssh_packet_set_default_callbacks(session);
set_status(session, 0.5f);
session->session_state=SSH_SESSION_STATE_INITIAL_KEX;
if (ssh_send_kex(session, 1) < 0) {
goto error;
}
break;
case SSH_SESSION_STATE_INITIAL_KEX:
/* TODO: This state should disappear in favor of get_key handle */
break;
case SSH_SESSION_STATE_KEXINIT_RECEIVED:
set_status(session,0.6f);
if(session->next_crypto->server_kex.methods[0]==NULL){
if(server_set_kex(session) == SSH_ERROR)
goto error;
/* We are in a rekeying, so we need to send the server kex */
if(ssh_send_kex(session, 1) < 0)
goto error;
}
ssh_list_kex(&session->next_crypto->client_kex); // log client kex
if (ssh_kex_select_methods(session) < 0) {
goto error;
}
if (crypt_set_algorithms_server(session) == SSH_ERROR)
goto error;
set_status(session,0.8f);
session->session_state=SSH_SESSION_STATE_DH;
break;
case SSH_SESSION_STATE_DH:
if(session->dh_handshake_state==DH_STATE_FINISHED){
rc = ssh_packet_set_newkeys(session, SSH_DIRECTION_IN);
if (rc != SSH_OK) {
goto error;
}
/*
* If the client supports extension negotiation, we will send
* our supported extensions now. This is the first message after
* sending NEWKEYS message and after turning on crypto.
*/
if (session->extensions & SSH_EXT_NEGOTIATION &&
session->session_state != SSH_SESSION_STATE_AUTHENTICATED) {
/*
* Only send an SSH_MSG_EXT_INFO message the first time the client
* undergoes NEWKEYS. It is unexpected for this message to be sent
* upon rekey, and may cause clients to log error messages.
*
* The session_state can not be used for this purpose because it is
* re-set to SSH_SESSION_STATE_KEXINIT_RECEIVED during rekey. So,
* use the connected flag which transitions from non-zero below.
*
* See also:
* - https://bugzilla.mindrot.org/show_bug.cgi?id=2929
*/
if (session->connected == 0) {
ssh_server_send_extensions(session);
}
}
set_status(session,1.0f);
session->connected = 1;
session->session_state=SSH_SESSION_STATE_AUTHENTICATING;
if (session->flags & SSH_SESSION_FLAG_AUTHENTICATED)
session->session_state = SSH_SESSION_STATE_AUTHENTICATED;
}
break;
case SSH_SESSION_STATE_AUTHENTICATING:
break;
case SSH_SESSION_STATE_ERROR:
goto error;
default:
ssh_set_error(session,SSH_FATAL,"Invalid state %d",session->session_state);
}
return;
error:
ssh_socket_close(session->socket);
session->alive = 0;
session->session_state=SSH_SESSION_STATE_ERROR;
}
/**
* @internal
*
* @brief Gets the banner from socket and saves it in session.
* Updates the session state
*
* @param data pointer to the beginning of header
* @param len size of the banner
* @param user is a pointer to session
* @returns Number of bytes processed, or zero if the banner is not complete.
*/
static int callback_receive_banner(const void *data, size_t len, void *user) {
char *buffer = (char *) data;
ssh_session session = (ssh_session) user;
char *str = NULL;
size_t i;
int ret=0;
for (i = 0; i < len; i++) {
#ifdef WITH_PCAP
if(session->pcap_ctx && buffer[i] == '\n') {
ssh_pcap_context_write(session->pcap_ctx,
SSH_PCAP_DIR_IN,
buffer,
i + 1,
i + 1);
}
#endif
if (buffer[i] == '\r') {
buffer[i]='\0';
}
if (buffer[i] == '\n') {
buffer[i]='\0';
str = strdup(buffer);
/* number of bytes read */
ret = i + 1;
session->clientbanner = str;
session->session_state = SSH_SESSION_STATE_BANNER_RECEIVED;
SSH_LOG(SSH_LOG_PACKET, "Received banner: %s", str);
session->ssh_connection_callback(session);
return ret;
}
if(i > 127) {
/* Too big banner */
session->session_state = SSH_SESSION_STATE_ERROR;
ssh_set_error(session, SSH_FATAL, "Receiving banner: too large banner");
return 0;
}
}
return ret;
}
/* returns 0 until the key exchange is not finished */
static int ssh_server_kex_termination(void *s){
ssh_session session = s;
if (session->session_state != SSH_SESSION_STATE_ERROR &&
session->session_state != SSH_SESSION_STATE_AUTHENTICATING &&
session->session_state != SSH_SESSION_STATE_DISCONNECTED)
return 0;
else
return 1;
}
void ssh_set_auth_methods(ssh_session session, int auth_methods){
/* accept only methods in range */
session->auth.supported_methods = auth_methods & 0x3f;
}
/* Do the banner and key exchange */
int ssh_handle_key_exchange(ssh_session session) {
int rc;
if (session->session_state != SSH_SESSION_STATE_NONE)
goto pending;
rc = ssh_send_banner(session, 1);
if (rc < 0) {
return SSH_ERROR;
}
session->alive = 1;
session->ssh_connection_callback = ssh_server_connection_callback;
session->session_state = SSH_SESSION_STATE_SOCKET_CONNECTED;
ssh_socket_set_callbacks(session->socket,&session->socket_callbacks);
session->socket_callbacks.data=callback_receive_banner;
session->socket_callbacks.exception=ssh_socket_exception_callback;
session->socket_callbacks.userdata=session;
rc = server_set_kex(session);
if (rc < 0) {
return SSH_ERROR;
}
pending:
rc = ssh_handle_packets_termination(session, SSH_TIMEOUT_USER,
ssh_server_kex_termination,session);
SSH_LOG(SSH_LOG_PACKET, "ssh_handle_key_exchange: current state : %d",
session->session_state);
if (rc != SSH_OK)
return rc;
if (session->session_state == SSH_SESSION_STATE_ERROR ||
session->session_state == SSH_SESSION_STATE_DISCONNECTED) {
return SSH_ERROR;
}
return SSH_OK;
}
/* messages */
/** @internal
* replies to an SSH_AUTH packet with a default (denied) response.
*/
int ssh_auth_reply_default(ssh_session session,int partial) {
char methods_c[128] = {0};
int rc = SSH_ERROR;
if (session->auth.supported_methods == 0) {
session->auth.supported_methods = SSH_AUTH_METHOD_PUBLICKEY | SSH_AUTH_METHOD_PASSWORD;
}
if (session->auth.supported_methods & SSH_AUTH_METHOD_PUBLICKEY) {
strncat(methods_c, "publickey,",
sizeof(methods_c) - strlen(methods_c) - 1);
}
if (session->auth.supported_methods & SSH_AUTH_METHOD_GSSAPI_MIC){
strncat(methods_c,"gssapi-with-mic,",
sizeof(methods_c) - strlen(methods_c) - 1);
}
if (session->auth.supported_methods & SSH_AUTH_METHOD_INTERACTIVE) {
strncat(methods_c, "keyboard-interactive,",
sizeof(methods_c) - strlen(methods_c) - 1);
}
if (session->auth.supported_methods & SSH_AUTH_METHOD_PASSWORD) {
strncat(methods_c, "password,",
sizeof(methods_c) - strlen(methods_c) - 1);
}
if (session->auth.supported_methods & SSH_AUTH_METHOD_HOSTBASED) {
strncat(methods_c, "hostbased,",
sizeof(methods_c) - strlen(methods_c) - 1);
}
if (methods_c[0] == '\0' || methods_c[strlen(methods_c)-1] != ',') {
return SSH_ERROR;
}
/* Strip the comma. */
methods_c[strlen(methods_c) - 1] = '\0'; // strip the comma. We are sure there is at
SSH_LOG(SSH_LOG_PACKET,
"Sending a auth failure. methods that can continue: %s", methods_c);
rc = ssh_buffer_pack(session->out_buffer,
"bsb",
SSH2_MSG_USERAUTH_FAILURE,
methods_c,
partial ? 1 : 0);
if (rc != SSH_OK){
ssh_set_error_oom(session);
return SSH_ERROR;
}
rc = ssh_packet_send(session);
return rc;
}
static int ssh_message_channel_request_open_reply_default(ssh_message msg) {
int rc;
SSH_LOG(SSH_LOG_FUNCTIONS, "Refusing a channel");
rc = ssh_buffer_pack(msg->session->out_buffer,
"bdddd",
SSH2_MSG_CHANNEL_OPEN_FAILURE,
msg->channel_request_open.sender,
SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED,
0, /* reason is empty string */
0); /* language string */
if (rc != SSH_OK){
ssh_set_error_oom(msg->session);
return SSH_ERROR;
}
rc = ssh_packet_send(msg->session);
return rc;
}
static int ssh_message_channel_request_reply_default(ssh_message msg) {
uint32_t channel;
int rc;
if (msg->channel_request.want_reply) {
channel = msg->channel_request.channel->remote_channel;
SSH_LOG(SSH_LOG_PACKET,
"Sending a default channel_request denied to channel %d", channel);
rc = ssh_buffer_pack(msg->session->out_buffer,
"bd",
SSH2_MSG_CHANNEL_FAILURE,
channel);
if (rc != SSH_OK){
ssh_set_error_oom(msg->session);
return SSH_ERROR;
}
return ssh_packet_send(msg->session);
}
SSH_LOG(SSH_LOG_PACKET,
"The client doesn't want to know the request failed!");
return SSH_OK;
}
static int ssh_message_service_request_reply_default(ssh_message msg) {
/* The only return code accepted by specifications are success or disconnect */
return ssh_message_service_reply_success(msg);
}
int ssh_message_service_reply_success(ssh_message msg) {
ssh_session session;
int rc;
if (msg == NULL) {
return SSH_ERROR;
}
session = msg->session;
SSH_LOG(SSH_LOG_PACKET,
"Sending a SERVICE_ACCEPT for service %s", msg->service_request.service);
rc = ssh_buffer_pack(session->out_buffer,
"bs",
SSH2_MSG_SERVICE_ACCEPT,
msg->service_request.service);
if (rc != SSH_OK){
ssh_set_error_oom(session);
return SSH_ERROR;
}
rc = ssh_packet_send(msg->session);
return rc;
}
int ssh_message_global_request_reply_success(ssh_message msg, uint16_t bound_port) {
int rc;
SSH_LOG(SSH_LOG_FUNCTIONS, "Accepting a global request");
if (msg->global_request.want_reply) {
if (ssh_buffer_add_u8(msg->session->out_buffer
, SSH2_MSG_REQUEST_SUCCESS) < 0) {
goto error;
}
if(msg->global_request.type == SSH_GLOBAL_REQUEST_TCPIP_FORWARD
&& msg->global_request.bind_port == 0) {
rc = ssh_buffer_pack(msg->session->out_buffer, "d", bound_port);
if (rc != SSH_OK) {
ssh_set_error_oom(msg->session);
goto error;
}
}
return ssh_packet_send(msg->session);
}
if(msg->global_request.type == SSH_GLOBAL_REQUEST_TCPIP_FORWARD
&& msg->global_request.bind_port == 0) {
SSH_LOG(SSH_LOG_PACKET,
"The client doesn't want to know the remote port!");
}
return SSH_OK;
error:
return SSH_ERROR;
}
static int ssh_message_global_request_reply_default(ssh_message msg) {
SSH_LOG(SSH_LOG_FUNCTIONS, "Refusing a global request");
if (msg->global_request.want_reply) {
if (ssh_buffer_add_u8(msg->session->out_buffer
, SSH2_MSG_REQUEST_FAILURE) < 0) {
goto error;
}
return ssh_packet_send(msg->session);
}
SSH_LOG(SSH_LOG_PACKET,
"The client doesn't want to know the request failed!");
return SSH_OK;
error:
return SSH_ERROR;
}
int ssh_message_reply_default(ssh_message msg) {
if (msg == NULL) {
return -1;
}
switch(msg->type) {
case SSH_REQUEST_AUTH:
return ssh_auth_reply_default(msg->session, 0);
case SSH_REQUEST_CHANNEL_OPEN:
return ssh_message_channel_request_open_reply_default(msg);
case SSH_REQUEST_CHANNEL:
return ssh_message_channel_request_reply_default(msg);
case SSH_REQUEST_SERVICE:
return ssh_message_service_request_reply_default(msg);
case SSH_REQUEST_GLOBAL:
return ssh_message_global_request_reply_default(msg);
default:
SSH_LOG(SSH_LOG_PACKET,
"Don't know what to default reply to %d type",
msg->type);
break;
}
return -1;
}
const char *ssh_message_service_service(ssh_message msg){
if (msg == NULL) {
return NULL;
}
return msg->service_request.service;
}
const char *ssh_message_auth_user(ssh_message msg) {
if (msg == NULL) {
return NULL;
}
return msg->auth_request.username;
}
const char *ssh_message_auth_password(ssh_message msg){
if (msg == NULL) {
return NULL;
}
return msg->auth_request.password;
}
ssh_key ssh_message_auth_pubkey(ssh_message msg) {
if (msg == NULL) {
return NULL;
}
return msg->auth_request.pubkey;
}
/* Get the publickey of an auth request */
ssh_public_key ssh_message_auth_publickey(ssh_message msg){
if (msg == NULL) {
return NULL;
}
return ssh_pki_convert_key_to_publickey(msg->auth_request.pubkey);
}
enum ssh_publickey_state_e ssh_message_auth_publickey_state(ssh_message msg){
if (msg == NULL) {
return -1;
}
return msg->auth_request.signature_state;
}
int ssh_message_auth_kbdint_is_response(ssh_message msg) {
if (msg == NULL) {
return -1;
}
return msg->auth_request.kbdint_response != 0;
}
int ssh_message_auth_set_methods(ssh_message msg, int methods) {
if (msg == NULL || msg->session == NULL) {
return -1;
}
msg->session->auth.supported_methods = methods;
return 0;
}
int ssh_message_auth_interactive_request(ssh_message msg, const char *name,
const char *instruction, unsigned int num_prompts,
const char **prompts, char *echo) {
int rc;
unsigned int i = 0;
if(name == NULL || instruction == NULL) {
return SSH_ERROR;
}
if(num_prompts > 0 && (prompts == NULL || echo == NULL)) {
return SSH_ERROR;
}
rc = ssh_buffer_pack(msg->session->out_buffer,
"bsssd",
SSH2_MSG_USERAUTH_INFO_REQUEST,
name,
instruction,
"", /* language tag */
num_prompts);
if (rc != SSH_OK){
ssh_set_error_oom(msg->session);
return SSH_ERROR;
}
for(i = 0; i < num_prompts; i++) {
rc = ssh_buffer_pack(msg->session->out_buffer,
"sb",
prompts[i],
echo[i] ? 1 : 0);
if (rc != SSH_OK){
ssh_set_error_oom(msg->session);
return SSH_ERROR;
}
}
rc = ssh_packet_send(msg->session);
/* fill in the kbdint structure */
if (msg->session->kbdint == NULL) {
SSH_LOG(SSH_LOG_PROTOCOL, "Warning: Got a "
"keyboard-interactive response but it "
"seems we didn't send the request.");
msg->session->kbdint = ssh_kbdint_new();
if (msg->session->kbdint == NULL) {
ssh_set_error_oom(msg->session);
return SSH_ERROR;
}
} else {
ssh_kbdint_clean(msg->session->kbdint);
}
msg->session->kbdint->name = strdup(name);
if(msg->session->kbdint->name == NULL) {
ssh_set_error_oom(msg->session);
ssh_kbdint_free(msg->session->kbdint);
msg->session->kbdint = NULL;
return SSH_PACKET_USED;
}
msg->session->kbdint->instruction = strdup(instruction);
if(msg->session->kbdint->instruction == NULL) {
ssh_set_error_oom(msg->session);
ssh_kbdint_free(msg->session->kbdint);
msg->session->kbdint = NULL;
return SSH_PACKET_USED;
}
msg->session->kbdint->nprompts = num_prompts;
if(num_prompts > 0) {
msg->session->kbdint->prompts = calloc(num_prompts, sizeof(char *));
if (msg->session->kbdint->prompts == NULL) {
msg->session->kbdint->nprompts = 0;
ssh_set_error_oom(msg->session);
ssh_kbdint_free(msg->session->kbdint);
msg->session->kbdint = NULL;
return SSH_ERROR;
}
msg->session->kbdint->echo = calloc(num_prompts, sizeof(unsigned char));
if (msg->session->kbdint->echo == NULL) {
ssh_set_error_oom(msg->session);
ssh_kbdint_free(msg->session->kbdint);
msg->session->kbdint = NULL;
return SSH_ERROR;
}
for (i = 0; i < num_prompts; i++) {
msg->session->kbdint->echo[i] = echo[i];
msg->session->kbdint->prompts[i] = strdup(prompts[i]);
if (msg->session->kbdint->prompts[i] == NULL) {
ssh_set_error_oom(msg->session);
msg->session->kbdint->nprompts = i;
ssh_kbdint_free(msg->session->kbdint);
msg->session->kbdint = NULL;
return SSH_PACKET_USED;
}
}
} else {
msg->session->kbdint->prompts = NULL;
msg->session->kbdint->echo = NULL;
}
msg->session->auth.state = SSH_AUTH_STATE_INFO;
return rc;
}
int ssh_auth_reply_success(ssh_session session, int partial)
{
struct ssh_crypto_struct *crypto = NULL;
int r;
if (session == NULL) {
return SSH_ERROR;
}
if (partial) {
return ssh_auth_reply_default(session, partial);
}
r = ssh_buffer_add_u8(session->out_buffer,SSH2_MSG_USERAUTH_SUCCESS);
if (r < 0) {
return SSH_ERROR;
}
r = ssh_packet_send(session);
/*
* Consider the session as having been authenticated only after sending
* the USERAUTH_SUCCESS message. Setting these flags after ssh_packet_send
* ensures that a rekey is not triggered prematurely, causing the message
* to be queued.
*/
session->session_state = SSH_SESSION_STATE_AUTHENTICATED;
session->flags |= SSH_SESSION_FLAG_AUTHENTICATED;
crypto = ssh_packet_get_current_crypto(session, SSH_DIRECTION_OUT);
if (crypto != NULL && crypto->delayed_compress_out) {
SSH_LOG(SSH_LOG_PROTOCOL, "Enabling delayed compression OUT");
crypto->do_compress_out = 1;
}
crypto = ssh_packet_get_current_crypto(session, SSH_DIRECTION_IN);
if (crypto != NULL && crypto->delayed_compress_in) {
SSH_LOG(SSH_LOG_PROTOCOL, "Enabling delayed compression IN");
crypto->do_compress_in = 1;
}
return r;
}
int ssh_message_auth_reply_success(ssh_message msg, int partial) {
if(msg == NULL)
return SSH_ERROR;
return ssh_auth_reply_success(msg->session, partial);
}
/* Answer OK to a pubkey auth request */
int ssh_message_auth_reply_pk_ok(ssh_message msg, ssh_string algo, ssh_string pubkey) {
int rc;
if (msg == NULL) {
return SSH_ERROR;
}
rc = ssh_buffer_pack(msg->session->out_buffer,
"bSS",
SSH2_MSG_USERAUTH_PK_OK,
algo,
pubkey);
if(rc != SSH_OK){
ssh_set_error_oom(msg->session);
return SSH_ERROR;
}
rc = ssh_packet_send(msg->session);
return rc;
}
int ssh_message_auth_reply_pk_ok_simple(ssh_message msg) {
ssh_string algo;
ssh_string pubkey_blob = NULL;
int ret;
algo = ssh_string_from_char(msg->auth_request.pubkey->type_c);
if (algo == NULL) {
return SSH_ERROR;
}
ret = ssh_pki_export_pubkey_blob(msg->auth_request.pubkey, &pubkey_blob);
if (ret < 0) {
ssh_string_free(algo);
return SSH_ERROR;
}
ret = ssh_message_auth_reply_pk_ok(msg, algo, pubkey_blob);
ssh_string_free(algo);
ssh_string_free(pubkey_blob);
return ret;
}
const char *ssh_message_channel_request_open_originator(ssh_message msg){
return msg->channel_request_open.originator;
}
int ssh_message_channel_request_open_originator_port(ssh_message msg){
return msg->channel_request_open.originator_port;
}
const char *ssh_message_channel_request_open_destination(ssh_message msg){
return msg->channel_request_open.destination;
}
int ssh_message_channel_request_open_destination_port(ssh_message msg){
return msg->channel_request_open.destination_port;
}
ssh_channel ssh_message_channel_request_channel(ssh_message msg){
return msg->channel_request.channel;
}
const char *ssh_message_channel_request_pty_term(ssh_message msg){
return msg->channel_request.TERM;
}
int ssh_message_channel_request_pty_width(ssh_message msg){
return msg->channel_request.width;
}
int ssh_message_channel_request_pty_height(ssh_message msg){
return msg->channel_request.height;
}
int ssh_message_channel_request_pty_pxwidth(ssh_message msg){
return msg->channel_request.pxwidth;
}
int ssh_message_channel_request_pty_pxheight(ssh_message msg){
return msg->channel_request.pxheight;
}
const char *ssh_message_channel_request_env_name(ssh_message msg){
return msg->channel_request.var_name;
}
const char *ssh_message_channel_request_env_value(ssh_message msg){
return msg->channel_request.var_value;
}
const char *ssh_message_channel_request_command(ssh_message msg){
return msg->channel_request.command;
}
const char *ssh_message_channel_request_subsystem(ssh_message msg){
return msg->channel_request.subsystem;
}
int ssh_message_channel_request_x11_single_connection(ssh_message msg){
return msg->channel_request.x11_single_connection ? 1 : 0;
}
const char *ssh_message_channel_request_x11_auth_protocol(ssh_message msg){
return msg->channel_request.x11_auth_protocol;
}
const char *ssh_message_channel_request_x11_auth_cookie(ssh_message msg){
return msg->channel_request.x11_auth_cookie;
}
int ssh_message_channel_request_x11_screen_number(ssh_message msg){
return msg->channel_request.x11_screen_number;
}
const char *ssh_message_global_request_address(ssh_message msg){
return msg->global_request.bind_address;
}
int ssh_message_global_request_port(ssh_message msg){
return msg->global_request.bind_port;
}
/** @brief defines the ssh_message callback
* @param session the current ssh session
* @param[in] ssh_bind_message_callback a function pointer to a callback taking the
* current ssh session and received message as parameters. the function returns
* 0 if the message has been parsed and treated successfully, 1 otherwise (libssh
* must take care of the response).
* @param[in] data void pointer to be passed to callback functions
*/
void ssh_set_message_callback(ssh_session session,
int(*ssh_bind_message_callback)(ssh_session session, ssh_message msg, void *data),
void *data) {
session->ssh_message_callback = ssh_bind_message_callback;
session->ssh_message_callback_data = data;
}
int ssh_execute_message_callbacks(ssh_session session){
ssh_message msg=NULL;
int ret;
ssh_handle_packets(session, SSH_TIMEOUT_NONBLOCKING);
if(!session->ssh_message_list)
return SSH_OK;
if(session->ssh_message_callback){
while((msg=ssh_message_pop_head(session)) != NULL) {
ret=session->ssh_message_callback(session,msg,
session->ssh_message_callback_data);
if(ret==1){
ret = ssh_message_reply_default(msg);
ssh_message_free(msg);
if(ret != SSH_OK)
return ret;
} else {
ssh_message_free(msg);
}
}
} else {
while((msg=ssh_message_pop_head(session)) != NULL) {
ret = ssh_message_reply_default(msg);
ssh_message_free(msg);
if(ret != SSH_OK)
return ret;
}
}
return SSH_OK;
}
int ssh_send_keepalive(ssh_session session)
{
/* Client denies the request, so the error code is not meaningful */
(void)ssh_global_request(session, "keepalive@openssh.com", NULL, 1);
return SSH_OK;
}
/** @} */
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