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ssh.c
3352 lines (2948 loc) · 106 KB
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ssh.c
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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, 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.haxx.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.
*
***************************************************************************/
/* #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_UTSNAME_H
#include <sys/utsname.h>
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#ifdef __VMS
#include <in.h>
#include <inet.h>
#endif
#if (defined(NETWARE) && defined(__NOVELL_LIBC__))
#undef in_addr_t
#define in_addr_t unsigned long
#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 "connect.h"
#include "strerror.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"
/* The last 3 #include files should be in this order */
#include "curl_printf.h"
#include "curl_memory.h"
#include "curl_path.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_last_error(s) curlx_ultosi(libssh2_sftp_last_error(s))
#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(int 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_connect(struct connectdata *conn, bool *done);
static CURLcode ssh_multi_statemach(struct connectdata *conn, bool *done);
static CURLcode ssh_do(struct connectdata *conn, bool *done);
static CURLcode scp_done(struct connectdata *conn,
CURLcode, bool premature);
static CURLcode scp_doing(struct connectdata *conn,
bool *dophase_done);
static CURLcode scp_disconnect(struct connectdata *conn, bool dead_connection);
static CURLcode sftp_done(struct connectdata *conn,
CURLcode, bool premature);
static CURLcode sftp_doing(struct connectdata *conn,
bool *dophase_done);
static CURLcode sftp_disconnect(struct connectdata *conn, bool dead);
static
CURLcode sftp_perform(struct connectdata *conn,
bool *connected,
bool *dophase_done);
static int ssh_getsock(struct connectdata *conn,
curl_socket_t *sock, /* points to numsocks number
of sockets */
int numsocks);
static int ssh_perform_getsock(const struct connectdata *conn,
curl_socket_t *sock, /* points to numsocks
number of sockets */
int numsocks);
static CURLcode ssh_setup_connection(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_perform_getsock, /* perform_getsock */
scp_disconnect, /* disconnect */
ZERO_NULL, /* readwrite */
ZERO_NULL, /* connection_check */
PORT_SSH, /* defport */
CURLPROTO_SCP, /* protocol */
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_perform_getsock, /* perform_getsock */
sftp_disconnect, /* disconnect */
ZERO_NULL, /* readwrite */
ZERO_NULL, /* connection_check */
PORT_SSH, /* defport */
CURLPROTO_SFTP, /* protocol */
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 connectdata *conn = (struct connectdata *)*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) {
responses[0].text = strdup(conn->passwd);
responses[0].length = curlx_uztoui(strlen(conn->passwd));
}
(void)prompts;
(void)abstract;
} /* kbd_callback */
static CURLcode sftp_libssh2_error_to_CURLE(int 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;
}
/* TODO: map some more of the libssh2 errors to the more appropriate CURLcode
error code, and possibly add a few new SSH-related one. We must however
not return or even depend on libssh2 errors in the public libcurl API */
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 connectdata *conn, sshstate nowstate)
{
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(conn->data, "SFTP %p state change from %s to %s\n",
(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 libssh2_session_startup(x,y) libssh2_session_handshake(x,y)
#endif
static CURLcode ssh_knownhost(struct connectdata *conn)
{
CURLcode result = CURLE_OK;
#ifdef HAVE_LIBSSH2_KNOWNHOST_API
struct Curl_easy *data = conn->data;
if(data->set.str[STRING_SSH_KNOWNHOSTS]) {
/* we're asked to verify the host against a file */
struct ssh_conn *sshc = &conn->proto.sshc;
int rc;
int keytype;
size_t keylen;
const char *remotekey = libssh2_session_hostkey(sshc->ssh_session,
&keylen, &keytype);
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?
*/
struct libssh2_knownhost *host;
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;
keybit = (keytype == LIBSSH2_HOSTKEY_TYPE_RSA)?
LIBSSH2_KNOWNHOST_KEY_SSHRSA:LIBSSH2_KNOWNHOST_KEY_SSHDSS;
#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\n", 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 = (keytype == LIBSSH2_HOSTKEY_TYPE_RSA)?
CURLKHTYPE_RSA : CURLKHTYPE_DSS;
knownkeyp = &knownkey;
}
/* setup 'foundkey' */
foundkey.key = remotekey;
foundkey.len = keylen;
foundkey.keytype = (keytype == LIBSSH2_HOSTKEY_TYPE_RSA)?
CURLKHTYPE_RSA : CURLKHTYPE_DSS;
/*
* 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(conn, 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:
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!\n",
conn->host.name);
else if(rc == CURLKHSTAT_FINE_ADD_TO_FILE) {
/* 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!\n",
data->set.str[STRING_SSH_KNOWNHOSTS]);
}
}
}
break;
}
}
#else /* HAVE_LIBSSH2_KNOWNHOST_API */
(void)conn;
#endif
return result;
}
static CURLcode ssh_check_fingerprint(struct connectdata *conn)
{
struct ssh_conn *sshc = &conn->proto.sshc;
struct Curl_easy *data = conn->data;
const char *pubkey_md5 = data->set.str[STRING_SSH_HOST_PUBLIC_KEY_MD5];
char md5buffer[33];
int i;
const char *fingerprint = libssh2_hostkey_hash(sshc->ssh_session,
LIBSSH2_HOSTKEY_HASH_MD5);
if(fingerprint) {
/* The fingerprint points to static storage (!), don't free() it. */
for(i = 0; i < 16; i++)
msnprintf(&md5buffer[i*2], 3, "%02x", (unsigned char) fingerprint[i]);
infof(data, "SSH MD5 fingerprint: %s\n", md5buffer);
}
/* Before we authenticate we check the hostkey's MD5 fingerprint
* against a known fingerprint, if available.
*/
if(pubkey_md5 && strlen(pubkey_md5) == 32) {
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(conn, SSH_SESSION_FREE);
sshc->actualcode = CURLE_PEER_FAILED_VERIFICATION;
return sshc->actualcode;
}
infof(data, "MD5 checksum match!\n");
/* as we already matched, we skip the check for known hosts */
return CURLE_OK;
}
return ssh_knownhost(conn);
}
/*
* 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 connectdata *conn, bool *block)
{
CURLcode result = CURLE_OK;
struct Curl_easy *data = conn->data;
struct SSHPROTO *sftp_scp = data->req.protop;
struct ssh_conn *sshc = &conn->proto.sshc;
curl_socket_t sock = conn->sock[FIRSTSOCKET];
char *new_readdir_line;
int rc = LIBSSH2_ERROR_NONE;
int err;
int seekerr = CURL_SEEKFUNC_OK;
*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);
state(conn, SSH_S_STARTUP);
/* FALLTHROUGH */
case SSH_S_STARTUP:
rc = libssh2_session_startup(sshc->ssh_session, (int)sock);
if(rc == LIBSSH2_ERROR_EAGAIN) {
break;
}
if(rc) {
char *err_msg = NULL;
(void)libssh2_session_last_error(sshc->ssh_session, &err_msg, NULL, 0);
failf(data, "Failure establishing ssh session: %d, %s", rc, err_msg);
state(conn, SSH_SESSION_FREE);
sshc->actualcode = CURLE_FAILED_INIT;
break;
}
state(conn, SSH_HOSTKEY);
/* FALLTHROUGH */
case SSH_HOSTKEY:
/*
* Before we authenticate we should check the hostkey's fingerprint
* against our known hosts. How that is handled (reading from file,
* whatever) is up to us.
*/
result = ssh_check_fingerprint(conn);
if(!result)
state(conn, SSH_AUTHLIST);
/* ssh_check_fingerprint sets state appropriately on error */
break;
case SSH_AUTHLIST:
/*
* Figure out authentication methods
* NB: As soon as we have provided a username to an openssh server we
* must never change it later. Thus, always specify the correct username
* here, even though the libssh2 docs kind of indicate that it should be
* possible to get a 'generic' list (not user-specific) of authentication
* methods, presumably with a blank username. That won't work in my
* experience.
* So always specify it here.
*/
sshc->authlist = libssh2_userauth_list(sshc->ssh_session,
conn->user,
curlx_uztoui(strlen(conn->user)));
if(!sshc->authlist) {
if(libssh2_userauth_authenticated(sshc->ssh_session)) {
sshc->authed = TRUE;
infof(data, "SSH user accepted with no authentication\n");
state(conn, SSH_AUTH_DONE);
break;
}
err = libssh2_session_last_errno(sshc->ssh_session);
if(err == LIBSSH2_ERROR_EAGAIN)
rc = LIBSSH2_ERROR_EAGAIN;
else {
state(conn, SSH_SESSION_FREE);
sshc->actualcode = libssh2_session_error_to_CURLE(err);
}
break;
}
infof(data, "SSH authentication methods available: %s\n",
sshc->authlist);
state(conn, SSH_AUTH_PKEY_INIT);
break;
case SSH_AUTH_PKEY_INIT:
/*
* Check the supported auth types in the order I feel is most secure
* with the requested type of authentication
*/
sshc->authed = FALSE;
if((data->set.ssh_auth_types & CURLSSH_AUTH_PUBLICKEY) &&
(strstr(sshc->authlist, "publickey") != NULL)) {
char *home = NULL;
bool out_of_memory = FALSE;
sshc->rsa_pub = sshc->rsa = NULL;
/* To ponder about: should really the lib be messing about with the
HOME environment variable etc? */
home = curl_getenv("HOME");
if(data->set.str[STRING_SSH_PRIVATE_KEY])
sshc->rsa = strdup(data->set.str[STRING_SSH_PRIVATE_KEY]);
else {
/* If no private key file is specified, try some common paths. */
if(home) {
/* Try ~/.ssh first. */
sshc->rsa = aprintf("%s/.ssh/id_rsa", home);
if(!sshc->rsa)
out_of_memory = TRUE;
else if(access(sshc->rsa, R_OK) != 0) {
Curl_safefree(sshc->rsa);
sshc->rsa = aprintf("%s/.ssh/id_dsa", home);
if(!sshc->rsa)
out_of_memory = TRUE;
else if(access(sshc->rsa, R_OK) != 0) {
Curl_safefree(sshc->rsa);
}
}
}
if(!out_of_memory && !sshc->rsa) {
/* Nothing found; try the current dir. */
sshc->rsa = strdup("id_rsa");
if(sshc->rsa && access(sshc->rsa, R_OK) != 0) {
Curl_safefree(sshc->rsa);
sshc->rsa = strdup("id_dsa");
if(sshc->rsa && access(sshc->rsa, R_OK) != 0) {
Curl_safefree(sshc->rsa);
/* Out of guesses. Set to the empty string to avoid
* surprising info messages. */
sshc->rsa = strdup("");
}
}
}
}
/*
* Unless the user explicitly specifies a public key file, let
* libssh2 extract the public key from the private key file.
* This is done by simply passing sshc->rsa_pub = NULL.
*/
if(data->set.str[STRING_SSH_PUBLIC_KEY]
/* treat empty string the same way as NULL */
&& data->set.str[STRING_SSH_PUBLIC_KEY][0]) {
sshc->rsa_pub = strdup(data->set.str[STRING_SSH_PUBLIC_KEY]);
if(!sshc->rsa_pub)
out_of_memory = TRUE;
}
if(out_of_memory || sshc->rsa == NULL) {
free(home);
Curl_safefree(sshc->rsa);
Curl_safefree(sshc->rsa_pub);
state(conn, SSH_SESSION_FREE);
sshc->actualcode = CURLE_OUT_OF_MEMORY;
break;
}
sshc->passphrase = data->set.ssl.key_passwd;
if(!sshc->passphrase)
sshc->passphrase = "";
free(home);
if(sshc->rsa_pub)
infof(data, "Using SSH public key file '%s'\n", sshc->rsa_pub);
infof(data, "Using SSH private key file '%s'\n", sshc->rsa);
state(conn, SSH_AUTH_PKEY);
}
else {
state(conn, SSH_AUTH_PASS_INIT);
}
break;
case SSH_AUTH_PKEY:
/* The function below checks if the files exists, no need to stat() here.
*/
rc = libssh2_userauth_publickey_fromfile_ex(sshc->ssh_session,
conn->user,
curlx_uztoui(
strlen(conn->user)),
sshc->rsa_pub,
sshc->rsa, sshc->passphrase);
if(rc == LIBSSH2_ERROR_EAGAIN) {
break;
}
Curl_safefree(sshc->rsa_pub);
Curl_safefree(sshc->rsa);
if(rc == 0) {
sshc->authed = TRUE;
infof(data, "Initialized SSH public key authentication\n");
state(conn, SSH_AUTH_DONE);
}
else {
char *err_msg = NULL;
(void)libssh2_session_last_error(sshc->ssh_session,
&err_msg, NULL, 0);
infof(data, "SSH public key authentication failed: %s\n", err_msg);
state(conn, SSH_AUTH_PASS_INIT);
rc = 0; /* clear rc and continue */
}
break;
case SSH_AUTH_PASS_INIT:
if((data->set.ssh_auth_types & CURLSSH_AUTH_PASSWORD) &&
(strstr(sshc->authlist, "password") != NULL)) {
state(conn, SSH_AUTH_PASS);
}
else {
state(conn, SSH_AUTH_HOST_INIT);
rc = 0; /* clear rc and continue */
}
break;
case SSH_AUTH_PASS:
rc = libssh2_userauth_password_ex(sshc->ssh_session, conn->user,
curlx_uztoui(strlen(conn->user)),
conn->passwd,
curlx_uztoui(strlen(conn->passwd)),
NULL);
if(rc == LIBSSH2_ERROR_EAGAIN) {
break;
}
if(rc == 0) {
sshc->authed = TRUE;
infof(data, "Initialized password authentication\n");
state(conn, SSH_AUTH_DONE);
}
else {
state(conn, SSH_AUTH_HOST_INIT);
rc = 0; /* clear rc and continue */
}
break;
case SSH_AUTH_HOST_INIT:
if((data->set.ssh_auth_types & CURLSSH_AUTH_HOST) &&
(strstr(sshc->authlist, "hostbased") != NULL)) {
state(conn, SSH_AUTH_HOST);
}
else {
state(conn, SSH_AUTH_AGENT_INIT);
}
break;
case SSH_AUTH_HOST:
state(conn, SSH_AUTH_AGENT_INIT);
break;
case SSH_AUTH_AGENT_INIT:
#ifdef HAVE_LIBSSH2_AGENT_API
if((data->set.ssh_auth_types & CURLSSH_AUTH_AGENT)
&& (strstr(sshc->authlist, "publickey") != NULL)) {
/* Connect to the ssh-agent */
/* The agent could be shared by a curl thread i believe
but nothing obvious as keys can be added/removed at any time */
if(!sshc->ssh_agent) {
sshc->ssh_agent = libssh2_agent_init(sshc->ssh_session);
if(!sshc->ssh_agent) {
infof(data, "Could not create agent object\n");
state(conn, SSH_AUTH_KEY_INIT);
break;
}
}
rc = libssh2_agent_connect(sshc->ssh_agent);
if(rc == LIBSSH2_ERROR_EAGAIN)
break;
if(rc < 0) {
infof(data, "Failure connecting to agent\n");
state(conn, SSH_AUTH_KEY_INIT);
rc = 0; /* clear rc and continue */
}
else {
state(conn, SSH_AUTH_AGENT_LIST);
}
}
else
#endif /* HAVE_LIBSSH2_AGENT_API */
state(conn, SSH_AUTH_KEY_INIT);
break;
case SSH_AUTH_AGENT_LIST:
#ifdef HAVE_LIBSSH2_AGENT_API
rc = libssh2_agent_list_identities(sshc->ssh_agent);
if(rc == LIBSSH2_ERROR_EAGAIN)
break;
if(rc < 0) {
infof(data, "Failure requesting identities to agent\n");
state(conn, SSH_AUTH_KEY_INIT);
rc = 0; /* clear rc and continue */
}
else {
state(conn, SSH_AUTH_AGENT);
sshc->sshagent_prev_identity = NULL;
}
#endif
break;
case SSH_AUTH_AGENT:
#ifdef HAVE_LIBSSH2_AGENT_API
/* as prev_identity evolves only after an identity user auth finished we
can safely request it again as long as EAGAIN is returned here or by
libssh2_agent_userauth */
rc = libssh2_agent_get_identity(sshc->ssh_agent,
&sshc->sshagent_identity,
sshc->sshagent_prev_identity);
if(rc == LIBSSH2_ERROR_EAGAIN)
break;
if(rc == 0) {
rc = libssh2_agent_userauth(sshc->ssh_agent, conn->user,
sshc->sshagent_identity);
if(rc < 0) {
if(rc != LIBSSH2_ERROR_EAGAIN) {
/* tried and failed? go to next identity */
sshc->sshagent_prev_identity = sshc->sshagent_identity;
}
break;
}
}
if(rc < 0)
infof(data, "Failure requesting identities to agent\n");
else if(rc == 1)
infof(data, "No identity would match\n");
if(rc == LIBSSH2_ERROR_NONE) {
sshc->authed = TRUE;
infof(data, "Agent based authentication successful\n");
state(conn, SSH_AUTH_DONE);
}
else {
state(conn, SSH_AUTH_KEY_INIT);
rc = 0; /* clear rc and continue */
}
#endif
break;
case SSH_AUTH_KEY_INIT:
if((data->set.ssh_auth_types & CURLSSH_AUTH_KEYBOARD)
&& (strstr(sshc->authlist, "keyboard-interactive") != NULL)) {
state(conn, SSH_AUTH_KEY);
}
else {
state(conn, SSH_AUTH_DONE);
}