static int
check_host_key_hash(BDRVSSHState *s, const char *hash,
int hash_type, size_t fingerprint_len, Error **errp)
{
const char *fingerprint;
fingerprint = libssh2_hostkey_hash(s->session, hash_type);
if (!fingerprint) {
session_error_setg(errp, s, "failed to read remote host key");
return -EINVAL;
}
if(compare_fingerprint((unsigned char *) fingerprint, fingerprint_len,
hash) != 0) {
error_setg(errp, "remote host key does not match host_key_check '%s'",
hash);
return -EPERM;
}
return 0;
}
static int connect_to_ssh(BDRVSSHState *s, QDict *options,
int ssh_flags, int creat_mode, Error **errp)
{
int r, ret;
const char *host, *user, *path, *host_key_check;
int port;
if (!qdict_haskey(options, "host")) {
ret = -EINVAL;
error_setg(errp, "No hostname was specified");
goto err;
}
host = qdict_get_str(options, "host");
if (qdict_haskey(options, "port")) {
port = qdict_get_int(options, "port");
} else {
port = 22;
}
if (!qdict_haskey(options, "path")) {
ret = -EINVAL;
error_setg(errp, "No path was specified");
goto err;
}
path = qdict_get_str(options, "path");
if (qdict_haskey(options, "user")) {
user = qdict_get_str(options, "user");
} else {
user = g_get_user_name();
if (!user) {
error_setg_errno(errp, errno, "Can't get user name");
ret = -errno;
goto err;
}
}
if (qdict_haskey(options, "host_key_check")) {
host_key_check = qdict_get_str(options, "host_key_check");
} else {
host_key_check = "yes";
}
/* Construct the host:port name for inet_connect. */
g_free(s->hostport);
s->hostport = g_strdup_printf("%s:%d", host, port);
/* Open the socket and connect. */
s->sock = inet_connect(s->hostport, errp);
if (s->sock < 0) {
ret = -errno;
goto err;
}
/* Create SSH session. */
s->session = libssh2_session_init();
if (!s->session) {
ret = -EINVAL;
session_error_setg(errp, s, "failed to initialize libssh2 session");
goto err;
}
#if TRACE_LIBSSH2 != 0
libssh2_trace(s->session, TRACE_LIBSSH2);
#endif
r = libssh2_session_handshake(s->session, s->sock);
if (r != 0) {
ret = -EINVAL;
session_error_setg(errp, s, "failed to establish SSH session");
goto err;
}
/* Check the remote host's key against known_hosts. */
ret = check_host_key(s, host, port, host_key_check, errp);
if (ret < 0) {
goto err;
}
/* Authenticate. */
ret = authenticate(s, user, errp);
if (ret < 0) {
goto err;
}
/* Start SFTP. */
s->sftp = libssh2_sftp_init(s->session);
if (!s->sftp) {
session_error_setg(errp, s, "failed to initialize sftp handle");
ret = -EINVAL;
goto err;
}
/* Open the remote file. */
DPRINTF("opening file %s flags=0x%x creat_mode=0%o",
path, ssh_flags, creat_mode);
s->sftp_handle = libssh2_sftp_open(s->sftp, path, ssh_flags, creat_mode);
if (!s->sftp_handle) {
session_error_setg(errp, s, "failed to open remote file '%s'", path);
ret = -EINVAL;
goto err;
}
r = libssh2_sftp_fstat(s->sftp_handle, &s->attrs);
if (r < 0) {
sftp_error_setg(errp, s, "failed to read file attributes");
return -EINVAL;
}
/* Delete the options we've used; any not deleted will cause the
* block layer to give an error about unused options.
*/
qdict_del(options, "host");
qdict_del(options, "port");
qdict_del(options, "user");
qdict_del(options, "path");
qdict_del(options, "host_key_check");
return 0;
err:
if (s->sftp_handle) {
libssh2_sftp_close(s->sftp_handle);
}
s->sftp_handle = NULL;
if (s->sftp) {
libssh2_sftp_shutdown(s->sftp);
}
s->sftp = NULL;
if (s->session) {
libssh2_session_disconnect(s->session,
"from qemu ssh client: "
"error opening connection");
libssh2_session_free(s->session);
}
s->session = NULL;
return ret;
}
static int authenticate(BDRVSSHState *s, const char *user, Error **errp)
{
int r, ret;
const char *userauthlist;
LIBSSH2_AGENT *agent = NULL;
struct libssh2_agent_publickey *identity;
struct libssh2_agent_publickey *prev_identity = NULL;
userauthlist = libssh2_userauth_list(s->session, user, strlen(user));
if (strstr(userauthlist, "publickey") == NULL) {
ret = -EPERM;
error_setg(errp,
"remote server does not support \"publickey\" authentication");
goto out;
}
/* Connect to ssh-agent and try each identity in turn. */
agent = libssh2_agent_init(s->session);
if (!agent) {
ret = -EINVAL;
session_error_setg(errp, s, "failed to initialize ssh-agent support");
goto out;
}
if (libssh2_agent_connect(agent)) {
ret = -ECONNREFUSED;
session_error_setg(errp, s, "failed to connect to ssh-agent");
goto out;
}
if (libssh2_agent_list_identities(agent)) {
ret = -EINVAL;
session_error_setg(errp, s,
"failed requesting identities from ssh-agent");
goto out;
}
for(;;) {
r = libssh2_agent_get_identity(agent, &identity, prev_identity);
if (r == 1) { /* end of list */
break;
}
if (r < 0) {
ret = -EINVAL;
session_error_setg(errp, s,
"failed to obtain identity from ssh-agent");
goto out;
}
r = libssh2_agent_userauth(agent, user, identity);
if (r == 0) {
/* Authenticated! */
ret = 0;
goto out;
}
/* Failed to authenticate with this identity, try the next one. */
prev_identity = identity;
}
ret = -EPERM;
error_setg(errp, "failed to authenticate using publickey authentication "
"and the identities held by your ssh-agent");
out:
if (agent != NULL) {
/* Note: libssh2 implementation implicitly calls
* libssh2_agent_disconnect if necessary.
*/
libssh2_agent_free(agent);
}
return ret;
}
static int check_host_key_knownhosts(BDRVSSHState *s,
const char *host, int port, Error **errp)
{
const char *home;
char *knh_file = NULL;
LIBSSH2_KNOWNHOSTS *knh = NULL;
struct libssh2_knownhost *found;
int ret, r;
const char *hostkey;
size_t len;
int type;
hostkey = libssh2_session_hostkey(s->session, &len, &type);
if (!hostkey) {
ret = -EINVAL;
session_error_setg(errp, s, "failed to read remote host key");
goto out;
}
knh = libssh2_knownhost_init(s->session);
if (!knh) {
ret = -EINVAL;
session_error_setg(errp, s,
"failed to initialize known hosts support");
goto out;
}
home = getenv("HOME");
if (home) {
knh_file = g_strdup_printf("%s/.ssh/known_hosts", home);
} else {
knh_file = g_strdup_printf("/root/.ssh/known_hosts");
}
/* Read all known hosts from OpenSSH-style known_hosts file. */
libssh2_knownhost_readfile(knh, knh_file, LIBSSH2_KNOWNHOST_FILE_OPENSSH);
r = libssh2_knownhost_checkp(knh, host, port, hostkey, len,
LIBSSH2_KNOWNHOST_TYPE_PLAIN|
LIBSSH2_KNOWNHOST_KEYENC_RAW,
&found);
switch (r) {
case LIBSSH2_KNOWNHOST_CHECK_MATCH:
/* OK */
DPRINTF("host key OK: %s", found->key);
break;
case LIBSSH2_KNOWNHOST_CHECK_MISMATCH:
ret = -EINVAL;
session_error_setg(errp, s,
"host key does not match the one in known_hosts"
" (found key %s)", found->key);
goto out;
case LIBSSH2_KNOWNHOST_CHECK_NOTFOUND:
ret = -EINVAL;
session_error_setg(errp, s, "no host key was found in known_hosts");
goto out;
case LIBSSH2_KNOWNHOST_CHECK_FAILURE:
ret = -EINVAL;
session_error_setg(errp, s,
"failure matching the host key with known_hosts");
goto out;
default:
ret = -EINVAL;
session_error_setg(errp, s, "unknown error matching the host key"
" with known_hosts (%d)", r);
goto out;
}
/* known_hosts checking successful. */
ret = 0;
out:
if (knh != NULL) {
libssh2_knownhost_free(knh);
}
g_free(knh_file);
return ret;
}
static int connect_to_ssh(BDRVSSHState *s, QDict *options,
int ssh_flags, int creat_mode, Error **errp)
{
int r, ret;
QemuOpts *opts = NULL;
Error *local_err = NULL;
const char *user, *path, *host_key_check;
long port = 0;
opts = qemu_opts_create(&ssh_runtime_opts, NULL, 0, &error_abort);
qemu_opts_absorb_qdict(opts, options, &local_err);
if (local_err) {
ret = -EINVAL;
error_propagate(errp, local_err);
goto err;
}
if (!ssh_process_legacy_socket_options(options, opts, errp)) {
ret = -EINVAL;
goto err;
}
path = qemu_opt_get(opts, "path");
if (!path) {
ret = -EINVAL;
error_setg(errp, "No path was specified");
goto err;
}
user = qemu_opt_get(opts, "user");
if (!user) {
user = g_get_user_name();
if (!user) {
error_setg_errno(errp, errno, "Can't get user name");
ret = -errno;
goto err;
}
}
host_key_check = qemu_opt_get(opts, "host_key_check");
if (!host_key_check) {
host_key_check = "yes";
}
/* Pop the config into our state object, Exit if invalid */
s->inet = ssh_config(s, options, errp);
if (!s->inet) {
ret = -EINVAL;
goto err;
}
if (qemu_strtol(s->inet->port, NULL, 10, &port) < 0) {
error_setg(errp, "Use only numeric port value");
ret = -EINVAL;
goto err;
}
/* Open the socket and connect. */
s->sock = inet_connect_saddr(s->inet, errp, NULL, NULL);
if (s->sock < 0) {
ret = -EIO;
goto err;
}
/* Create SSH session. */
s->session = libssh2_session_init();
if (!s->session) {
ret = -EINVAL;
session_error_setg(errp, s, "failed to initialize libssh2 session");
goto err;
}
#if TRACE_LIBSSH2 != 0
libssh2_trace(s->session, TRACE_LIBSSH2);
#endif
r = libssh2_session_handshake(s->session, s->sock);
if (r != 0) {
ret = -EINVAL;
session_error_setg(errp, s, "failed to establish SSH session");
goto err;
}
/* Check the remote host's key against known_hosts. */
ret = check_host_key(s, s->inet->host, port, host_key_check,
errp);
if (ret < 0) {
goto err;
}
/* Authenticate. */
ret = authenticate(s, user, errp);
if (ret < 0) {
goto err;
}
/* Start SFTP. */
s->sftp = libssh2_sftp_init(s->session);
if (!s->sftp) {
session_error_setg(errp, s, "failed to initialize sftp handle");
ret = -EINVAL;
goto err;
}
/* Open the remote file. */
DPRINTF("opening file %s flags=0x%x creat_mode=0%o",
path, ssh_flags, creat_mode);
s->sftp_handle = libssh2_sftp_open(s->sftp, path, ssh_flags, creat_mode);
if (!s->sftp_handle) {
session_error_setg(errp, s, "failed to open remote file '%s'", path);
ret = -EINVAL;
goto err;
}
qemu_opts_del(opts);
r = libssh2_sftp_fstat(s->sftp_handle, &s->attrs);
if (r < 0) {
sftp_error_setg(errp, s, "failed to read file attributes");
return -EINVAL;
}
return 0;
err:
if (s->sftp_handle) {
libssh2_sftp_close(s->sftp_handle);
}
s->sftp_handle = NULL;
if (s->sftp) {
libssh2_sftp_shutdown(s->sftp);
}
s->sftp = NULL;
if (s->session) {
libssh2_session_disconnect(s->session,
"from qemu ssh client: "
"error opening connection");
libssh2_session_free(s->session);
}
s->session = NULL;
qemu_opts_del(opts);
return ret;
}