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libssh2.c
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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) Daniel Stenberg, <[email protected]>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* SPDX-License-Identifier: curl
*
***************************************************************************/
/* #define CURL_LIBSSH2_DEBUG */
#include "curl_setup.h"
#ifdef USE_LIBSSH2
#include <limits.h>
#include <libssh2.h>
#include <libssh2_sftp.h>
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#ifdef __VMS
#include <in.h>
#include <inet.h>
#endif
#include <curl/curl.h>
#include "urldata.h"
#include "sendf.h"
#include "hostip.h"
#include "progress.h"
#include "transfer.h"
#include "escape.h"
#include "http.h" /* for HTTP proxy tunnel stuff */
#include "ssh.h"
#include "url.h"
#include "speedcheck.h"
#include "getinfo.h"
#include "strdup.h"
#include "strcase.h"
#include "vtls/vtls.h"
#include "cfilters.h"
#include "connect.h"
#include "inet_ntop.h"
#include "parsedate.h" /* for the week day and month names */
#include "sockaddr.h" /* required for Curl_sockaddr_storage */
#include "strtoofft.h"
#include "multiif.h"
#include "select.h"
#include "warnless.h"
#include "curl_path.h"
#include <curl_base64.h> /* for base64 encoding/decoding */
#include <curl_sha256.h>
/* The last 3 #include files should be in this order */
#include "curl_printf.h"
#include "curl_memory.h"
#include "memdebug.h"
#if LIBSSH2_VERSION_NUM >= 0x010206
/* libssh2_sftp_statvfs and friends were added in 1.2.6 */
#define HAS_STATVFS_SUPPORT 1
#endif
#define sftp_libssh2_realpath(s,p,t,m) \
libssh2_sftp_symlink_ex((s), (p), curlx_uztoui(strlen(p)), \
(t), (m), LIBSSH2_SFTP_REALPATH)
/* Local functions: */
static const char *sftp_libssh2_strerror(unsigned long err);
static LIBSSH2_ALLOC_FUNC(my_libssh2_malloc);
static LIBSSH2_REALLOC_FUNC(my_libssh2_realloc);
static LIBSSH2_FREE_FUNC(my_libssh2_free);
static CURLcode ssh_force_knownhost_key_type(struct Curl_easy *data);
static CURLcode ssh_connect(struct Curl_easy *data, bool *done);
static CURLcode ssh_multi_statemach(struct Curl_easy *data, bool *done);
static CURLcode ssh_do(struct Curl_easy *data, bool *done);
static CURLcode scp_done(struct Curl_easy *data, CURLcode c, bool premature);
static CURLcode scp_doing(struct Curl_easy *data, bool *dophase_done);
static CURLcode scp_disconnect(struct Curl_easy *data,
struct connectdata *conn, bool dead_connection);
static CURLcode sftp_done(struct Curl_easy *data, CURLcode, bool premature);
static CURLcode sftp_doing(struct Curl_easy *data, bool *dophase_done);
static CURLcode sftp_disconnect(struct Curl_easy *data,
struct connectdata *conn, bool dead);
static CURLcode sftp_perform(struct Curl_easy *data, bool *connected,
bool *dophase_done);
static int ssh_getsock(struct Curl_easy *data, struct connectdata *conn,
curl_socket_t *sock);
static CURLcode ssh_setup_connection(struct Curl_easy *data,
struct connectdata *conn);
static void ssh_attach(struct Curl_easy *data, struct connectdata *conn);
/*
* SCP protocol handler.
*/
const struct Curl_handler Curl_handler_scp = {
"SCP", /* scheme */
ssh_setup_connection, /* setup_connection */
ssh_do, /* do_it */
scp_done, /* done */
ZERO_NULL, /* do_more */
ssh_connect, /* connect_it */
ssh_multi_statemach, /* connecting */
scp_doing, /* doing */
ssh_getsock, /* proto_getsock */
ssh_getsock, /* doing_getsock */
ZERO_NULL, /* domore_getsock */
ssh_getsock, /* perform_getsock */
scp_disconnect, /* disconnect */
ZERO_NULL, /* readwrite */
ZERO_NULL, /* connection_check */
ssh_attach, /* attach */
PORT_SSH, /* defport */
CURLPROTO_SCP, /* protocol */
CURLPROTO_SCP, /* family */
PROTOPT_DIRLOCK | PROTOPT_CLOSEACTION
| PROTOPT_NOURLQUERY /* flags */
};
/*
* SFTP protocol handler.
*/
const struct Curl_handler Curl_handler_sftp = {
"SFTP", /* scheme */
ssh_setup_connection, /* setup_connection */
ssh_do, /* do_it */
sftp_done, /* done */
ZERO_NULL, /* do_more */
ssh_connect, /* connect_it */
ssh_multi_statemach, /* connecting */
sftp_doing, /* doing */
ssh_getsock, /* proto_getsock */
ssh_getsock, /* doing_getsock */
ZERO_NULL, /* domore_getsock */
ssh_getsock, /* perform_getsock */
sftp_disconnect, /* disconnect */
ZERO_NULL, /* readwrite */
ZERO_NULL, /* connection_check */
ssh_attach, /* attach */
PORT_SSH, /* defport */
CURLPROTO_SFTP, /* protocol */
CURLPROTO_SFTP, /* family */
PROTOPT_DIRLOCK | PROTOPT_CLOSEACTION
| PROTOPT_NOURLQUERY /* flags */
};
static void
kbd_callback(const char *name, int name_len, const char *instruction,
int instruction_len, int num_prompts,
const LIBSSH2_USERAUTH_KBDINT_PROMPT *prompts,
LIBSSH2_USERAUTH_KBDINT_RESPONSE *responses,
void **abstract)
{
struct Curl_easy *data = (struct Curl_easy *)*abstract;
#ifdef CURL_LIBSSH2_DEBUG
fprintf(stderr, "name=%s\n", name);
fprintf(stderr, "name_len=%d\n", name_len);
fprintf(stderr, "instruction=%s\n", instruction);
fprintf(stderr, "instruction_len=%d\n", instruction_len);
fprintf(stderr, "num_prompts=%d\n", num_prompts);
#else
(void)name;
(void)name_len;
(void)instruction;
(void)instruction_len;
#endif /* CURL_LIBSSH2_DEBUG */
if(num_prompts == 1) {
struct connectdata *conn = data->conn;
responses[0].text = strdup(conn->passwd);
responses[0].length = curlx_uztoui(strlen(conn->passwd));
}
(void)prompts;
} /* kbd_callback */
static CURLcode sftp_libssh2_error_to_CURLE(unsigned long err)
{
switch(err) {
case LIBSSH2_FX_OK:
return CURLE_OK;
case LIBSSH2_FX_NO_SUCH_FILE:
case LIBSSH2_FX_NO_SUCH_PATH:
return CURLE_REMOTE_FILE_NOT_FOUND;
case LIBSSH2_FX_PERMISSION_DENIED:
case LIBSSH2_FX_WRITE_PROTECT:
case LIBSSH2_FX_LOCK_CONFlICT:
return CURLE_REMOTE_ACCESS_DENIED;
case LIBSSH2_FX_NO_SPACE_ON_FILESYSTEM:
case LIBSSH2_FX_QUOTA_EXCEEDED:
return CURLE_REMOTE_DISK_FULL;
case LIBSSH2_FX_FILE_ALREADY_EXISTS:
return CURLE_REMOTE_FILE_EXISTS;
case LIBSSH2_FX_DIR_NOT_EMPTY:
return CURLE_QUOTE_ERROR;
default:
break;
}
return CURLE_SSH;
}
static CURLcode libssh2_session_error_to_CURLE(int err)
{
switch(err) {
/* Ordered by order of appearance in libssh2.h */
case LIBSSH2_ERROR_NONE:
return CURLE_OK;
/* This is the error returned by libssh2_scp_recv2
* on unknown file */
case LIBSSH2_ERROR_SCP_PROTOCOL:
return CURLE_REMOTE_FILE_NOT_FOUND;
case LIBSSH2_ERROR_SOCKET_NONE:
return CURLE_COULDNT_CONNECT;
case LIBSSH2_ERROR_ALLOC:
return CURLE_OUT_OF_MEMORY;
case LIBSSH2_ERROR_SOCKET_SEND:
return CURLE_SEND_ERROR;
case LIBSSH2_ERROR_HOSTKEY_INIT:
case LIBSSH2_ERROR_HOSTKEY_SIGN:
case LIBSSH2_ERROR_PUBLICKEY_UNRECOGNIZED:
case LIBSSH2_ERROR_PUBLICKEY_UNVERIFIED:
return CURLE_PEER_FAILED_VERIFICATION;
case LIBSSH2_ERROR_PASSWORD_EXPIRED:
return CURLE_LOGIN_DENIED;
case LIBSSH2_ERROR_SOCKET_TIMEOUT:
case LIBSSH2_ERROR_TIMEOUT:
return CURLE_OPERATION_TIMEDOUT;
case LIBSSH2_ERROR_EAGAIN:
return CURLE_AGAIN;
}
return CURLE_SSH;
}
static LIBSSH2_ALLOC_FUNC(my_libssh2_malloc)
{
(void)abstract; /* arg not used */
return malloc(count);
}
static LIBSSH2_REALLOC_FUNC(my_libssh2_realloc)
{
(void)abstract; /* arg not used */
return realloc(ptr, count);
}
static LIBSSH2_FREE_FUNC(my_libssh2_free)
{
(void)abstract; /* arg not used */
if(ptr) /* ssh2 agent sometimes call free with null ptr */
free(ptr);
}
/*
* SSH State machine related code
*/
/* This is the ONLY way to change SSH state! */
static void state(struct Curl_easy *data, sshstate nowstate)
{
struct connectdata *conn = data->conn;
struct ssh_conn *sshc = &conn->proto.sshc;
#if defined(DEBUGBUILD) && !defined(CURL_DISABLE_VERBOSE_STRINGS)
/* for debug purposes */
static const char * const names[] = {
"SSH_STOP",
"SSH_INIT",
"SSH_S_STARTUP",
"SSH_HOSTKEY",
"SSH_AUTHLIST",
"SSH_AUTH_PKEY_INIT",
"SSH_AUTH_PKEY",
"SSH_AUTH_PASS_INIT",
"SSH_AUTH_PASS",
"SSH_AUTH_AGENT_INIT",
"SSH_AUTH_AGENT_LIST",
"SSH_AUTH_AGENT",
"SSH_AUTH_HOST_INIT",
"SSH_AUTH_HOST",
"SSH_AUTH_KEY_INIT",
"SSH_AUTH_KEY",
"SSH_AUTH_GSSAPI",
"SSH_AUTH_DONE",
"SSH_SFTP_INIT",
"SSH_SFTP_REALPATH",
"SSH_SFTP_QUOTE_INIT",
"SSH_SFTP_POSTQUOTE_INIT",
"SSH_SFTP_QUOTE",
"SSH_SFTP_NEXT_QUOTE",
"SSH_SFTP_QUOTE_STAT",
"SSH_SFTP_QUOTE_SETSTAT",
"SSH_SFTP_QUOTE_SYMLINK",
"SSH_SFTP_QUOTE_MKDIR",
"SSH_SFTP_QUOTE_RENAME",
"SSH_SFTP_QUOTE_RMDIR",
"SSH_SFTP_QUOTE_UNLINK",
"SSH_SFTP_QUOTE_STATVFS",
"SSH_SFTP_GETINFO",
"SSH_SFTP_FILETIME",
"SSH_SFTP_TRANS_INIT",
"SSH_SFTP_UPLOAD_INIT",
"SSH_SFTP_CREATE_DIRS_INIT",
"SSH_SFTP_CREATE_DIRS",
"SSH_SFTP_CREATE_DIRS_MKDIR",
"SSH_SFTP_READDIR_INIT",
"SSH_SFTP_READDIR",
"SSH_SFTP_READDIR_LINK",
"SSH_SFTP_READDIR_BOTTOM",
"SSH_SFTP_READDIR_DONE",
"SSH_SFTP_DOWNLOAD_INIT",
"SSH_SFTP_DOWNLOAD_STAT",
"SSH_SFTP_CLOSE",
"SSH_SFTP_SHUTDOWN",
"SSH_SCP_TRANS_INIT",
"SSH_SCP_UPLOAD_INIT",
"SSH_SCP_DOWNLOAD_INIT",
"SSH_SCP_DOWNLOAD",
"SSH_SCP_DONE",
"SSH_SCP_SEND_EOF",
"SSH_SCP_WAIT_EOF",
"SSH_SCP_WAIT_CLOSE",
"SSH_SCP_CHANNEL_FREE",
"SSH_SESSION_DISCONNECT",
"SSH_SESSION_FREE",
"QUIT"
};
/* a precaution to make sure the lists are in sync */
DEBUGASSERT(sizeof(names)/sizeof(names[0]) == SSH_LAST);
if(sshc->state != nowstate) {
infof(data, "SFTP %p state change from %s to %s",
(void *)sshc, names[sshc->state], names[nowstate]);
}
#endif
sshc->state = nowstate;
}
#ifdef HAVE_LIBSSH2_KNOWNHOST_API
static int sshkeycallback(struct Curl_easy *easy,
const struct curl_khkey *knownkey, /* known */
const struct curl_khkey *foundkey, /* found */
enum curl_khmatch match,
void *clientp)
{
(void)easy;
(void)knownkey;
(void)foundkey;
(void)clientp;
/* we only allow perfect matches, and we reject everything else */
return (match != CURLKHMATCH_OK)?CURLKHSTAT_REJECT:CURLKHSTAT_FINE;
}
#endif
/*
* Earlier libssh2 versions didn't have the ability to seek to 64bit positions
* with 32bit size_t.
*/
#ifdef HAVE_LIBSSH2_SFTP_SEEK64
#define SFTP_SEEK(x,y) libssh2_sftp_seek64(x, (libssh2_uint64_t)y)
#else
#define SFTP_SEEK(x,y) libssh2_sftp_seek(x, (size_t)y)
#endif
/*
* Earlier libssh2 versions didn't do SCP properly beyond 32bit sizes on 32bit
* architectures so we check of the necessary function is present.
*/
#ifndef HAVE_LIBSSH2_SCP_SEND64
#define SCP_SEND(a,b,c,d) libssh2_scp_send_ex(a, b, (int)(c), (size_t)d, 0, 0)
#else
#define SCP_SEND(a,b,c,d) libssh2_scp_send64(a, b, (int)(c), \
(libssh2_uint64_t)d, 0, 0)
#endif
/*
* libssh2 1.2.8 fixed the problem with 32bit ints used for sockets on win64.
*/
#ifdef HAVE_LIBSSH2_SESSION_HANDSHAKE
#define session_startup(x,y) libssh2_session_handshake(x, y)
#else
#define session_startup(x,y) libssh2_session_startup(x, (int)y)
#endif
static int convert_ssh2_keytype(int sshkeytype)
{
int keytype = CURLKHTYPE_UNKNOWN;
switch(sshkeytype) {
case LIBSSH2_HOSTKEY_TYPE_RSA:
keytype = CURLKHTYPE_RSA;
break;
case LIBSSH2_HOSTKEY_TYPE_DSS:
keytype = CURLKHTYPE_DSS;
break;
#ifdef LIBSSH2_HOSTKEY_TYPE_ECDSA_256
case LIBSSH2_HOSTKEY_TYPE_ECDSA_256:
keytype = CURLKHTYPE_ECDSA;
break;
#endif
#ifdef LIBSSH2_HOSTKEY_TYPE_ECDSA_384
case LIBSSH2_HOSTKEY_TYPE_ECDSA_384:
keytype = CURLKHTYPE_ECDSA;
break;
#endif
#ifdef LIBSSH2_HOSTKEY_TYPE_ECDSA_521
case LIBSSH2_HOSTKEY_TYPE_ECDSA_521:
keytype = CURLKHTYPE_ECDSA;
break;
#endif
#ifdef LIBSSH2_HOSTKEY_TYPE_ED25519
case LIBSSH2_HOSTKEY_TYPE_ED25519:
keytype = CURLKHTYPE_ED25519;
break;
#endif
}
return keytype;
}
static CURLcode ssh_knownhost(struct Curl_easy *data)
{
int sshkeytype = 0;
size_t keylen = 0;
int rc = 0;
CURLcode result = CURLE_OK;
#ifdef HAVE_LIBSSH2_KNOWNHOST_API
if(data->set.str[STRING_SSH_KNOWNHOSTS]) {
/* we're asked to verify the host against a file */
struct connectdata *conn = data->conn;
struct ssh_conn *sshc = &conn->proto.sshc;
struct libssh2_knownhost *host = NULL;
const char *remotekey = libssh2_session_hostkey(sshc->ssh_session,
&keylen, &sshkeytype);
int keycheck = LIBSSH2_KNOWNHOST_CHECK_FAILURE;
int keybit = 0;
if(remotekey) {
/*
* A subject to figure out is what host name we need to pass in here.
* What host name does OpenSSH store in its file if an IDN name is
* used?
*/
enum curl_khmatch keymatch;
curl_sshkeycallback func =
data->set.ssh_keyfunc ? data->set.ssh_keyfunc : sshkeycallback;
struct curl_khkey knownkey;
struct curl_khkey *knownkeyp = NULL;
struct curl_khkey foundkey;
switch(sshkeytype) {
case LIBSSH2_HOSTKEY_TYPE_RSA:
keybit = LIBSSH2_KNOWNHOST_KEY_SSHRSA;
break;
case LIBSSH2_HOSTKEY_TYPE_DSS:
keybit = LIBSSH2_KNOWNHOST_KEY_SSHDSS;
break;
#ifdef LIBSSH2_HOSTKEY_TYPE_ECDSA_256
case LIBSSH2_HOSTKEY_TYPE_ECDSA_256:
keybit = LIBSSH2_KNOWNHOST_KEY_ECDSA_256;
break;
#endif
#ifdef LIBSSH2_HOSTKEY_TYPE_ECDSA_384
case LIBSSH2_HOSTKEY_TYPE_ECDSA_384:
keybit = LIBSSH2_KNOWNHOST_KEY_ECDSA_384;
break;
#endif
#ifdef LIBSSH2_HOSTKEY_TYPE_ECDSA_521
case LIBSSH2_HOSTKEY_TYPE_ECDSA_521:
keybit = LIBSSH2_KNOWNHOST_KEY_ECDSA_521;
break;
#endif
#ifdef LIBSSH2_HOSTKEY_TYPE_ED25519
case LIBSSH2_HOSTKEY_TYPE_ED25519:
keybit = LIBSSH2_KNOWNHOST_KEY_ED25519;
break;
#endif
default:
infof(data, "unsupported key type, can't check knownhosts");
keybit = 0;
break;
}
if(!keybit)
/* no check means failure! */
rc = CURLKHSTAT_REJECT;
else {
#ifdef HAVE_LIBSSH2_KNOWNHOST_CHECKP
keycheck = libssh2_knownhost_checkp(sshc->kh,
conn->host.name,
(conn->remote_port != PORT_SSH)?
conn->remote_port:-1,
remotekey, keylen,
LIBSSH2_KNOWNHOST_TYPE_PLAIN|
LIBSSH2_KNOWNHOST_KEYENC_RAW|
keybit,
&host);
#else
keycheck = libssh2_knownhost_check(sshc->kh,
conn->host.name,
remotekey, keylen,
LIBSSH2_KNOWNHOST_TYPE_PLAIN|
LIBSSH2_KNOWNHOST_KEYENC_RAW|
keybit,
&host);
#endif
infof(data, "SSH host check: %d, key: %s", keycheck,
(keycheck <= LIBSSH2_KNOWNHOST_CHECK_MISMATCH)?
host->key:"<none>");
/* setup 'knownkey' */
if(keycheck <= LIBSSH2_KNOWNHOST_CHECK_MISMATCH) {
knownkey.key = host->key;
knownkey.len = 0;
knownkey.keytype = convert_ssh2_keytype(sshkeytype);
knownkeyp = &knownkey;
}
/* setup 'foundkey' */
foundkey.key = remotekey;
foundkey.len = keylen;
foundkey.keytype = convert_ssh2_keytype(sshkeytype);
/*
* if any of the LIBSSH2_KNOWNHOST_CHECK_* defines and the
* curl_khmatch enum are ever modified, we need to introduce a
* translation table here!
*/
keymatch = (enum curl_khmatch)keycheck;
/* Ask the callback how to behave */
Curl_set_in_callback(data, true);
rc = func(data, knownkeyp, /* from the knownhosts file */
&foundkey, /* from the remote host */
keymatch, data->set.ssh_keyfunc_userp);
Curl_set_in_callback(data, false);
}
}
else
/* no remotekey means failure! */
rc = CURLKHSTAT_REJECT;
switch(rc) {
default: /* unknown return codes will equal reject */
/* FALLTHROUGH */
case CURLKHSTAT_REJECT:
state(data, SSH_SESSION_FREE);
/* FALLTHROUGH */
case CURLKHSTAT_DEFER:
/* DEFER means bail out but keep the SSH_HOSTKEY state */
result = sshc->actualcode = CURLE_PEER_FAILED_VERIFICATION;
break;
case CURLKHSTAT_FINE_REPLACE:
/* remove old host+key that doesn't match */
if(host)
libssh2_knownhost_del(sshc->kh, host);
/* FALLTHROUGH */
case CURLKHSTAT_FINE:
/* FALLTHROUGH */
case CURLKHSTAT_FINE_ADD_TO_FILE:
/* proceed */
if(keycheck != LIBSSH2_KNOWNHOST_CHECK_MATCH) {
/* the found host+key didn't match but has been told to be fine
anyway so we add it in memory */
int addrc = libssh2_knownhost_add(sshc->kh,
conn->host.name, NULL,
remotekey, keylen,
LIBSSH2_KNOWNHOST_TYPE_PLAIN|
LIBSSH2_KNOWNHOST_KEYENC_RAW|
keybit, NULL);
if(addrc)
infof(data, "WARNING: adding the known host %s failed",
conn->host.name);
else if(rc == CURLKHSTAT_FINE_ADD_TO_FILE ||
rc == CURLKHSTAT_FINE_REPLACE) {
/* now we write the entire in-memory list of known hosts to the
known_hosts file */
int wrc =
libssh2_knownhost_writefile(sshc->kh,
data->set.str[STRING_SSH_KNOWNHOSTS],
LIBSSH2_KNOWNHOST_FILE_OPENSSH);
if(wrc) {
infof(data, "WARNING: writing %s failed",
data->set.str[STRING_SSH_KNOWNHOSTS]);
}
}
}
break;
}
}
#else /* HAVE_LIBSSH2_KNOWNHOST_API */
(void)data;
#endif
return result;
}
static CURLcode ssh_check_fingerprint(struct Curl_easy *data)
{
struct connectdata *conn = data->conn;
struct ssh_conn *sshc = &conn->proto.sshc;
const char *pubkey_md5 = data->set.str[STRING_SSH_HOST_PUBLIC_KEY_MD5];
const char *pubkey_sha256 = data->set.str[STRING_SSH_HOST_PUBLIC_KEY_SHA256];
infof(data, "SSH MD5 public key: %s",
pubkey_md5 != NULL ? pubkey_md5 : "NULL");
infof(data, "SSH SHA256 public key: %s",
pubkey_sha256 != NULL ? pubkey_sha256 : "NULL");
if(pubkey_sha256) {
const char *fingerprint = NULL;
char *fingerprint_b64 = NULL;
size_t fingerprint_b64_len;
size_t pub_pos = 0;
size_t b64_pos = 0;
#ifdef LIBSSH2_HOSTKEY_HASH_SHA256
/* The fingerprint points to static storage (!), don't free() it. */
fingerprint = libssh2_hostkey_hash(sshc->ssh_session,
LIBSSH2_HOSTKEY_HASH_SHA256);
#else
const char *hostkey;
size_t len = 0;
unsigned char hash[32];
hostkey = libssh2_session_hostkey(sshc->ssh_session, &len, NULL);
if(hostkey) {
if(!Curl_sha256it(hash, (const unsigned char *) hostkey, len))
fingerprint = (char *) hash;
}
#endif
if(!fingerprint) {
failf(data,
"Denied establishing ssh session: sha256 fingerprint "
"not available");
state(data, SSH_SESSION_FREE);
sshc->actualcode = CURLE_PEER_FAILED_VERIFICATION;
return sshc->actualcode;
}
/* The length of fingerprint is 32 bytes for SHA256.
* See libssh2_hostkey_hash documentation. */
if(Curl_base64_encode(fingerprint, 32, &fingerprint_b64,
&fingerprint_b64_len) != CURLE_OK) {
state(data, SSH_SESSION_FREE);
sshc->actualcode = CURLE_PEER_FAILED_VERIFICATION;
return sshc->actualcode;
}
if(!fingerprint_b64) {
failf(data, "sha256 fingerprint could not be encoded");
state(data, SSH_SESSION_FREE);
sshc->actualcode = CURLE_PEER_FAILED_VERIFICATION;
return sshc->actualcode;
}
infof(data, "SSH SHA256 fingerprint: %s", fingerprint_b64);
/* Find the position of any = padding characters in the public key */
while((pubkey_sha256[pub_pos] != '=') && pubkey_sha256[pub_pos]) {
pub_pos++;
}
/* Find the position of any = padding characters in the base64 coded
* hostkey fingerprint */
while((fingerprint_b64[b64_pos] != '=') && fingerprint_b64[b64_pos]) {
b64_pos++;
}
/* Before we authenticate we check the hostkey's sha256 fingerprint
* against a known fingerprint, if available.
*/
if((pub_pos != b64_pos) ||
strncmp(fingerprint_b64, pubkey_sha256, pub_pos)) {
failf(data,
"Denied establishing ssh session: mismatch sha256 fingerprint. "
"Remote %s is not equal to %s", fingerprint_b64, pubkey_sha256);
free(fingerprint_b64);
state(data, SSH_SESSION_FREE);
sshc->actualcode = CURLE_PEER_FAILED_VERIFICATION;
return sshc->actualcode;
}
free(fingerprint_b64);
infof(data, "SHA256 checksum match");
}
if(pubkey_md5) {
char md5buffer[33];
const char *fingerprint = NULL;
fingerprint = libssh2_hostkey_hash(sshc->ssh_session,
LIBSSH2_HOSTKEY_HASH_MD5);
if(fingerprint) {
/* The fingerprint points to static storage (!), don't free() it. */
int i;
for(i = 0; i < 16; i++) {
msnprintf(&md5buffer[i*2], 3, "%02x", (unsigned char) fingerprint[i]);
}
infof(data, "SSH MD5 fingerprint: %s", md5buffer);
}
/* This does NOT verify the length of 'pubkey_md5' separately, which will
make the comparison below fail unless it is exactly 32 characters */
if(!fingerprint || !strcasecompare(md5buffer, pubkey_md5)) {
if(fingerprint) {
failf(data,
"Denied establishing ssh session: mismatch md5 fingerprint. "
"Remote %s is not equal to %s", md5buffer, pubkey_md5);
}
else {
failf(data,
"Denied establishing ssh session: md5 fingerprint "
"not available");
}
state(data, SSH_SESSION_FREE);
sshc->actualcode = CURLE_PEER_FAILED_VERIFICATION;
return sshc->actualcode;
}
infof(data, "MD5 checksum match");
}
if(!pubkey_md5 && !pubkey_sha256) {
if(data->set.ssh_hostkeyfunc) {
size_t keylen = 0;
int sshkeytype = 0;
int rc = 0;
/* we handle the process to the callback */
const char *remotekey = libssh2_session_hostkey(sshc->ssh_session,
&keylen, &sshkeytype);
if(remotekey) {
int keytype = convert_ssh2_keytype(sshkeytype);
Curl_set_in_callback(data, true);
rc = data->set.ssh_hostkeyfunc(data->set.ssh_hostkeyfunc_userp,
keytype, remotekey, keylen);
Curl_set_in_callback(data, false);
if(rc!= CURLKHMATCH_OK) {
state(data, SSH_SESSION_FREE);
sshc->actualcode = CURLE_PEER_FAILED_VERIFICATION;
return sshc->actualcode;
}
}
else {
state(data, SSH_SESSION_FREE);
sshc->actualcode = CURLE_PEER_FAILED_VERIFICATION;
return sshc->actualcode;
}
return CURLE_OK;
}
else {
return ssh_knownhost(data);
}
}
else {
/* as we already matched, we skip the check for known hosts */
return CURLE_OK;
}
}
/*
* ssh_force_knownhost_key_type() will check the known hosts file and try to
* force a specific public key type from the server if an entry is found.
*/
static CURLcode ssh_force_knownhost_key_type(struct Curl_easy *data)
{
CURLcode result = CURLE_OK;
#ifdef HAVE_LIBSSH2_KNOWNHOST_API
#ifdef LIBSSH2_KNOWNHOST_KEY_ED25519
static const char * const hostkey_method_ssh_ed25519
= "ssh-ed25519";
#endif
#ifdef LIBSSH2_KNOWNHOST_KEY_ECDSA_521
static const char * const hostkey_method_ssh_ecdsa_521
= "ecdsa-sha2-nistp521";
#endif
#ifdef LIBSSH2_KNOWNHOST_KEY_ECDSA_384
static const char * const hostkey_method_ssh_ecdsa_384
= "ecdsa-sha2-nistp384";
#endif
#ifdef LIBSSH2_KNOWNHOST_KEY_ECDSA_256
static const char * const hostkey_method_ssh_ecdsa_256
= "ecdsa-sha2-nistp256";
#endif
static const char * const hostkey_method_ssh_rsa
= "ssh-rsa";
static const char * const hostkey_method_ssh_rsa_all
= "rsa-sha2-256,rsa-sha2-512,ssh-rsa";
static const char * const hostkey_method_ssh_dss
= "ssh-dss";
const char *hostkey_method = NULL;
struct connectdata *conn = data->conn;
struct ssh_conn *sshc = &conn->proto.sshc;
struct libssh2_knownhost* store = NULL;
const char *kh_name_end = NULL;
size_t kh_name_size = 0;
int port = 0;
bool found = false;
if(sshc->kh && !data->set.str[STRING_SSH_HOST_PUBLIC_KEY_MD5]) {
/* lets try to find our host in the known hosts file */
while(!libssh2_knownhost_get(sshc->kh, &store, store)) {
/* For non-standard ports, the name will be enclosed in */
/* square brackets, followed by a colon and the port */
if(store) {
if(store->name) {
if(store->name[0] == '[') {
kh_name_end = strstr(store->name, "]:");
if(!kh_name_end) {
infof(data, "Invalid host pattern %s in %s",
store->name, data->set.str[STRING_SSH_KNOWNHOSTS]);
continue;
}
port = atoi(kh_name_end + 2);
if(kh_name_end && (port == conn->remote_port)) {
kh_name_size = strlen(store->name) - 1 - strlen(kh_name_end);
if(strncmp(store->name + 1,
conn->host.name, kh_name_size) == 0) {
found = true;
break;
}
}
}
else if(strcmp(store->name, conn->host.name) == 0) {
found = true;
break;
}
}
else {
found = true;
break;
}
}
}
if(found) {
int rc;
infof(data, "Found host %s in %s",
conn->host.name, data->set.str[STRING_SSH_KNOWNHOSTS]);
switch(store->typemask & LIBSSH2_KNOWNHOST_KEY_MASK) {
#ifdef LIBSSH2_KNOWNHOST_KEY_ED25519
case LIBSSH2_KNOWNHOST_KEY_ED25519:
hostkey_method = hostkey_method_ssh_ed25519;
break;
#endif
#ifdef LIBSSH2_KNOWNHOST_KEY_ECDSA_521
case LIBSSH2_KNOWNHOST_KEY_ECDSA_521:
hostkey_method = hostkey_method_ssh_ecdsa_521;
break;
#endif
#ifdef LIBSSH2_KNOWNHOST_KEY_ECDSA_384
case LIBSSH2_KNOWNHOST_KEY_ECDSA_384:
hostkey_method = hostkey_method_ssh_ecdsa_384;
break;
#endif
#ifdef LIBSSH2_KNOWNHOST_KEY_ECDSA_256
case LIBSSH2_KNOWNHOST_KEY_ECDSA_256:
hostkey_method = hostkey_method_ssh_ecdsa_256;
break;
#endif
case LIBSSH2_KNOWNHOST_KEY_SSHRSA:
#ifdef HAVE_LIBSSH2_VERSION
if(libssh2_version(0x010900))
/* since 1.9.0 libssh2_session_method_pref() works as expected */
hostkey_method = hostkey_method_ssh_rsa_all;
else
#endif
/* old libssh2 which cannot correctly remove unsupported methods due
* to bug in src/kex.c or does not support the new methods anyways.
*/
hostkey_method = hostkey_method_ssh_rsa;
break;
case LIBSSH2_KNOWNHOST_KEY_SSHDSS:
hostkey_method = hostkey_method_ssh_dss;
break;
case LIBSSH2_KNOWNHOST_KEY_RSA1:
failf(data, "Found host key type RSA1 which is not supported");
return CURLE_SSH;
default:
failf(data, "Unknown host key type: %i",
(store->typemask & LIBSSH2_KNOWNHOST_KEY_MASK));
return CURLE_SSH;
}
infof(data, "Set \"%s\" as SSH hostkey type", hostkey_method);
rc = libssh2_session_method_pref(sshc->ssh_session,
LIBSSH2_METHOD_HOSTKEY, hostkey_method);
if(rc) {
char *errmsg = NULL;
int errlen;
libssh2_session_last_error(sshc->ssh_session, &errmsg, &errlen, 0);
failf(data, "libssh2: %s", errmsg);
result = libssh2_session_error_to_CURLE(rc);
}
}
else {
infof(data, "Did not find host %s in %s",
conn->host.name, data->set.str[STRING_SSH_KNOWNHOSTS]);
}
}
#endif /* HAVE_LIBSSH2_KNOWNHOST_API */
return result;
}
/*
* ssh_statemach_act() runs the SSH state machine as far as it can without
* blocking and without reaching the end. The data the pointer 'block' points
* to will be set to TRUE if the libssh2 function returns LIBSSH2_ERROR_EAGAIN
* meaning it wants to be called again when the socket is ready
*/
static CURLcode ssh_statemach_act(struct Curl_easy *data, bool *block)
{
CURLcode result = CURLE_OK;
struct connectdata *conn = data->conn;
struct SSHPROTO *sshp = data->req.p.ssh;
struct ssh_conn *sshc = &conn->proto.sshc;
curl_socket_t sock = conn->sock[FIRSTSOCKET];
int rc = LIBSSH2_ERROR_NONE;
int ssherr;
unsigned long sftperr;
int seekerr = CURL_SEEKFUNC_OK;
size_t readdir_len;
*block = 0; /* we're not blocking by default */
do {
switch(sshc->state) {
case SSH_INIT:
sshc->secondCreateDirs = 0;
sshc->nextstate = SSH_NO_STATE;
sshc->actualcode = CURLE_OK;
/* Set libssh2 to non-blocking, since everything internally is
non-blocking */
libssh2_session_set_blocking(sshc->ssh_session, 0);
result = ssh_force_knownhost_key_type(data);
if(result) {
state(data, SSH_SESSION_FREE);
sshc->actualcode = result;
break;
}
state(data, SSH_S_STARTUP);
/* FALLTHROUGH */