Re: [libvirt] [PATCH v2 2/2] libssh_transport: add new libssh-based transport

Implement a new libssh transport, which uses libssh to communicate with remote hosts, and use it in virNetSockets. This new transport supports all the common ssh authentication methods, making use of libvirt's auth callbacks for interaction with the user. Most of the functionalities and implementation are based on the libssh2 transport. --- config-post.h | 2 + configure.ac | 3 + include/libvirt/virterror.h | 2 + m4/virt-libssh.m4 | 26 + src/Makefile.am | 21 +- src/libvirt_libssh.syms | 22 + src/remote/remote_driver.c | 41 ++ src/rpc/virnetclient.c | 123 ++++ src/rpc/virnetclient.h | 13 + src/rpc/virnetlibsshsession.c | 1424 +++++++++++++++++++++++++++++++++++++++++ src/rpc/virnetlibsshsession.h | 80 +++ src/rpc/virnetsocket.c | 179 ++++++ src/rpc/virnetsocket.h | 13 + src/util/virerror.c | 9 +- 14 files changed, 1955 insertions(+), 3 deletions(-) create mode 100644 m4/virt-libssh.m4 create mode 100644 src/libvirt_libssh.syms create mode 100644 src/rpc/virnetlibsshsession.c create mode 100644 src/rpc/virnetlibsshsession.h

diff --git a/include/libvirt/virterror.h b/include/libvirt/virterror.h index efe83aa..2efee8f 100644 --- a/include/libvirt/virterror.h +++ b/include/libvirt/virterror.h @@ -131,6 +131,7 @@ typedef enum { VIR_FROM_XENXL = 64, /* Error from Xen xl config code */ VIR_FROM_PERF = 65, /* Error from perf */ + VIR_FROM_LIBSSH = 66, /* Error from libssh connection transport */ # ifdef VIR_ENUM_SENTINELS VIR_ERR_DOMAIN_LAST @@ -317,6 +318,7 @@ typedef enum { VIR_ERR_NO_CLIENT = 96, /* Client was not found */ VIR_ERR_AGENT_UNSYNCED = 97, /* guest agent replies with wrong id to guest-sync command */ + VIR_ERR_LIBSSH = 98, /* error in libssh transport driver */

} virErrorNumber; /**

diff --git a/src/remote/remote_driver.c b/src/remote/remote_driver.c index a3cd7cd..db2bdd4 100644 --- a/src/remote/remote_driver.c +++ b/src/remote/remote_driver.c @@ -673,6 +673,7 @@ remoteConnectSupportsFeatureUnlocked(virConnectPtr conn, * - xxx:/// -> UNIX domain socket * - xxx+ssh:/// -> SSH connection (legacy) * - xxx+libssh2:/// -> SSH connection (using libssh2) + * - xxx+libssh:/// -> SSH connection (using libssh) */ static int doRemoteOpen(virConnectPtr conn, @@ -689,6 +690,7 @@ doRemoteOpen(virConnectPtr conn, trans_libssh2, trans_ext, trans_tcp, + trans_libssh, } transport; #ifndef WIN32 char *daemonPath = NULL; @@ -736,6 +738,8 @@ doRemoteOpen(virConnectPtr conn, transport = trans_ext; } else if (STRCASEEQ(transport_str, "tcp")) { transport = trans_tcp; + } else if (STRCASEEQ(transport_str, "libssh")) { + transport = trans_libssh; } else { virReportError(VIR_ERR_INVALID_ARG, "%s", _("remote_open: transport in URL not recognised " @@ -959,6 +963,43 @@ doRemoteOpen(virConnectPtr conn, priv->is_secure = 1; break; + case trans_libssh: + if (!sockname) { + /* Right now we don't support default session connections */ + if (STREQ_NULLABLE(conn->uri->path, "/session")) { + virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s", + _("Connecting to session instance without " + "socket path is not supported by the libssh " + "connection driver")); + goto failed; + } + + if (VIR_STRDUP(sockname, + flags & VIR_DRV_OPEN_REMOTE_RO ? + LIBVIRTD_PRIV_UNIX_SOCKET_RO : LIBVIRTD_PRIV_UNIX_SOCKET) < 0) + goto failed; + } + + VIR_DEBUG("Starting libssh session"); + + priv->client = virNetClientNewLibssh(priv->hostname, + port, + AF_UNSPEC, + username, + keyfile, + knownHosts, + knownHostsVerify, + sshauth, + netcat, + sockname, + auth, + conn->uri); + if (!priv->client) + goto failed; + + priv->is_secure = 1; + break; + #ifndef WIN32 case trans_unix: if (!sockname) {

diff --git a/src/rpc/virnetclient.c b/src/rpc/virnetclient.c index 361dc1a..b296aac 100644 --- a/src/rpc/virnetclient.c +++ b/src/rpc/virnetclient.c @@ -505,6 +505,129 @@ virNetClientPtr virNetClientNewLibSSH2(const char *host, } #undef DEFAULT_VALUE +#define DEFAULT_VALUE(VAR, VAL) \ + if (!VAR) \ + VAR = VAL; +virNetClientPtr virNetClientNewLibssh(const char *host, + const char *port, + int family, + const char *username, + const char *privkeyPath, + const char *knownHostsPath, + const char *knownHostsVerify, + const char *authMethods, + const char *netcatPath, + const char *socketPath, + virConnectAuthPtr authPtr, + virURIPtr uri) +{ + virNetSocketPtr sock = NULL; + virNetClientPtr ret = NULL; + + virBuffer buf = VIR_BUFFER_INITIALIZER; + char *nc = NULL; + char *command = NULL; + + char *homedir = virGetUserDirectory(); + char *confdir = virGetUserConfigDirectory(); + char *knownhosts = NULL; + char *privkey = NULL; + + /* Use default paths for known hosts an public keys if not provided */

+ if (confdir) { + if (!knownHostsPath) { + if (virFileExists(confdir)) { + virBufferAsprintf(&buf, "%s/known_hosts", confdir); + if (!(knownhosts = virBufferContentAndReset(&buf)))

+ goto no_memory; + } + } else { + if (VIR_STRDUP(knownhosts, knownHostsPath) < 0) + goto cleanup; + } + } + + if (homedir) { + if (!privkeyPath) { + /* RSA */ + virBufferAsprintf(&buf, "%s/.ssh/id_rsa", homedir); + if (!(privkey = virBufferContentAndReset(&buf)))

+ goto no_memory; + + if (!(virFileExists(privkey))) + VIR_FREE(privkey); + /* DSA */ + if (!privkey) { + virBufferAsprintf(&buf, "%s/.ssh/id_dsa", homedir); + if (!(privkey = virBufferContentAndReset(&buf)))

+ goto no_memory; + + if (!(virFileExists(privkey))) + VIR_FREE(privkey); + } + } else { + if (VIR_STRDUP(privkey, privkeyPath) < 0) + goto cleanup; + } + } + + if (!authMethods) { + if (privkey) + authMethods = "agent,privkey,password,keyboard-interactive"; + else + authMethods = "agent,password,keyboard-interactive"; + } + + DEFAULT_VALUE(host, "localhost"); + DEFAULT_VALUE(port, "22"); + DEFAULT_VALUE(username, "root"); + DEFAULT_VALUE(netcatPath, "nc"); + DEFAULT_VALUE(knownHostsVerify, "normal"); + + virBufferEscapeShell(&buf, netcatPath); + if (!(nc = virBufferContentAndReset(&buf))) + goto no_memory; + + virBufferAsprintf(&buf,

+ "sh -c " + "'if '%s' -q 2>&1 | grep \"requires an argument\" >/dev/null 2>&1; then " + "ARG=-q0;" + "else " + "ARG=;" + "fi;" + "'%s' $ARG -U %s'", + nc, nc, socketPath); + + if (!(command = virBufferContentAndReset(&buf))) + goto no_memory;

+ + if (virNetSocketNewConnectLibssh(host, port, + family, + username, privkey, + knownhosts, knownHostsVerify, authMethods, + command, authPtr, uri, &sock) != 0) + goto cleanup; + + if (!(ret = virNetClientNew(sock, NULL))) + goto cleanup; + sock = NULL; + + cleanup: + VIR_FREE(command); + VIR_FREE(privkey); + VIR_FREE(knownhosts); + VIR_FREE(homedir); + VIR_FREE(confdir); + VIR_FREE(nc); + virObjectUnref(sock); + return ret; + + no_memory: + virReportOOMError(); + goto cleanup; +} +#undef DEFAULT_VALUE + virNetClientPtr virNetClientNewExternal(const char **cmdargv) { virNetSocketPtr sock; diff --git a/src/rpc/virnetclient.h b/src/rpc/virnetclient.h index c772d0b..9cf3209 100644 --- a/src/rpc/virnetclient.h +++ b/src/rpc/virnetclient.h @@ -67,6 +67,19 @@ virNetClientPtr virNetClientNewLibSSH2(const char *host, virConnectAuthPtr authPtr, virURIPtr uri); +virNetClientPtr virNetClientNewLibssh(const char *host, + const char *port, + int family, + const char *username, + const char *privkeyPath, + const char *knownHostsPath, + const char *knownHostsVerify, + const char *authMethods, + const char *netcatPath, + const char *socketPath, + virConnectAuthPtr authPtr, + virURIPtr uri); + virNetClientPtr virNetClientNewExternal(const char **cmdargv); int virNetClientRegisterAsyncIO(virNetClientPtr client);

diff --git a/src/rpc/virnetlibsshsession.c b/src/rpc/virnetlibsshsession.c new file mode 100644 index 0000000..19990ea --- /dev/null +++ b/src/rpc/virnetlibsshsession.c @@ -0,0 +1,1424 @@ +/* + * virnetlibsshsession.c: ssh network transport provider based on libssh + * + * Copyright (C) 2012-2016 Red Hat, Inc. + * + * This 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. + * + * This 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 this library. If not, see + * <http://www.gnu.org/licenses/>;. + * + * Author: Peter Krempa <pkrempa(a)redhat.com&gt; + * Author: Pino Toscano <ptoscano(a)redhat.com&gt; + */ +#include <config.h> +#include <libssh/libssh.h> + +#include "virnetlibsshsession.h" + +#include "internal.h" +#include "viralloc.h" +#include "virlog.h" +#include "configmake.h" +#include "virutil.h" +#include "virerror.h" +#include "virobject.h" +#include "virstring.h" +#include "virauth.h" +#include "virbuffer.h" + +#define VIR_FROM_THIS VIR_FROM_LIBSSH + +VIR_LOG_INIT("rpc.netlibsshsession"); + +#define VIR_NET_LIBSSH_BUFFER_SIZE 1024 + +/* TRACE_LIBSSH=<level> enables tracing in libssh itself. + * The meaning of <level> is described here: + * http://api.libssh.org/master/group__libssh__log.html + * + * The LIBVIRT_LIBSSH_DEBUG environment variable can be used + * to set/override the level of libssh debug. + */ +#define TRACE_LIBSSH 0 + +typedef enum { + VIR_NET_LIBSSH_STATE_NEW, + VIR_NET_LIBSSH_STATE_HANDSHAKE_COMPLETE, + VIR_NET_LIBSSH_STATE_CLOSED, + VIR_NET_LIBSSH_STATE_ERROR, + VIR_NET_LIBSSH_STATE_ERROR_REMOTE, +} virNetLibsshSessionState; + +typedef enum { + VIR_NET_LIBSSH_AUTH_KEYBOARD_INTERACTIVE, + VIR_NET_LIBSSH_AUTH_PASSWORD, + VIR_NET_LIBSSH_AUTH_PRIVKEY, + VIR_NET_LIBSSH_AUTH_AGENT, + VIR_NET_LIBSSH_AUTH_COUNT /* keep it as last, used to count */ +} virNetLibsshAuthMethods; + + +typedef struct _virNetLibsshAuthMethod virNetLibsshAuthMethod; +typedef virNetLibsshAuthMethod *virNetLibsshAuthMethodPtr; + +struct _virNetLibsshAuthMethod { + virNetLibsshAuthMethods method; + char *password; + char *filename; + + int tries; +}; + +struct _virNetLibsshSession { + virObjectLockable parent; + virNetLibsshSessionState state; + + /* libssh internal stuff */ + ssh_session session; + ssh_channel channel; + + /* for host key checking */ + virNetLibsshHostkeyVerify hostKeyVerify; + char *knownHostsFile; + char *hostname; + int port; + + /* authentication stuff */ + char *username; + virConnectAuthPtr cred; + char *authPath; + virNetLibsshAuthMethodPtr auths[VIR_NET_LIBSSH_AUTH_COUNT]; + + /* channel stuff */ + char *channelCommand; + int channelCommandReturnValue; + + /* read cache */ + char rbuf[VIR_NET_LIBSSH_BUFFER_SIZE]; + size_t bufUsed; + size_t bufStart; +}; + +static void +virNetLibsshSessionAuthMethodFree(virNetLibsshAuthMethodPtr auth) +{ + if (!auth) + return; + + VIR_FREE(auth->password); + VIR_FREE(auth->filename); + VIR_FREE(auth); +} + +static void +virNetLibsshSessionAuthMethodsFree(virNetLibsshSessionPtr sess) +{ + size_t i; + + for (i = 0; i < ARRAY_CARDINALITY(sess->auths); ++i) { + virNetLibsshSessionAuthMethodFree(sess->auths[i]); + sess->auths[i] = NULL; + } +} + +static void +virNetLibsshSessionDispose(void *obj) +{ + virNetLibsshSessionPtr sess = obj; + VIR_DEBUG("sess=0x%p", sess); + + if (!sess) + return; + + if (sess->channel) { + ssh_channel_send_eof(sess->channel); + ssh_channel_close(sess->channel); + ssh_channel_free(sess->channel); + } + + if (sess->session) { + ssh_disconnect(sess->session); + ssh_free(sess->session); + } + + virNetLibsshSessionAuthMethodsFree(sess); + + VIR_FREE(sess->channelCommand); + VIR_FREE(sess->hostname); + VIR_FREE(sess->knownHostsFile); + VIR_FREE(sess->authPath); + VIR_FREE(sess->username); +} + +static virClassPtr virNetLibsshSessionClass; +static int +virNetLibsshSessionOnceInit(void) +{ + const char *dbgLevelStr; + + if (!(virNetLibsshSessionClass = virClassNew(virClassForObjectLockable(), + "virNetLibsshSession", + sizeof(virNetLibsshSession), + virNetLibsshSessionDispose))) + return -1; + + if (ssh_init() < 0) + return -1; + +#if TRACE_LIBSSH != 0 + ssh_set_log_level(TRACE_LIBSSH); +#endif + + dbgLevelStr = virGetEnvAllowSUID("LIBVIRT_LIBSSH_DEBUG"); + if (dbgLevelStr) { + int dbgLevel = virParseNumber(&dbgLevelStr); + ssh_set_log_level(dbgLevel); + } + + return 0; +} +VIR_ONCE_GLOBAL_INIT(virNetLibsshSession); + +static virNetLibsshAuthMethodPtr +virNetLibsshSessionAuthMethodNew(virNetLibsshSessionPtr sess, + virNetLibsshAuthMethods method) +{ + virNetLibsshAuthMethodPtr auth; + + virNetLibsshSessionAuthMethodFree(sess->auths[method]); + if (VIR_ALLOC(auth) < 0) + return NULL; + + sess->auths[method] = auth; + auth->method = method; + + return auth; +} + +/* string representation of public key of remote server */ +static char* +virSshServerKeyAsString(virNetLibsshSessionPtr sess) +{ + int ret; + ssh_key key; + unsigned char *keyhash; + size_t keyhashlen; + char *str; + + if (ssh_get_publickey(sess->session, &key) != SSH_OK) { + virReportError(VIR_ERR_LIBSSH, "%s", + _("failed to get the key of the current " + "session")); + return NULL; + } + + /* calculate remote key hash, using MD5 algorithm that is + * usual in OpenSSH. The returned value must be freed */ + ret = ssh_get_publickey_hash(key, SSH_PUBLICKEY_HASH_MD5, + &keyhash, &keyhashlen); + ssh_key_free(key); + if (ret < 0) { + virReportError(VIR_ERR_LIBSSH, "%s", + _("failed to calculate ssh host key hash")); + return NULL; + } + /* format the host key into a nice userfriendly string. */ + str = ssh_get_hexa(keyhash, keyhashlen); + ssh_clean_pubkey_hash(&keyhash); + + return str; +} + +static int +virCredTypeForPrompt(virConnectAuthPtr cred, char echo) +{ + unsigned int i; + + for (i = 0; i < cred->ncredtype; ++i) { + int type = cred->credtype[i]; + if (echo) { + if (type == VIR_CRED_ECHOPROMPT) { + return type; + } + } else { + if (type == VIR_CRED_PASSPHRASE || + type == VIR_CRED_NOECHOPROMPT) { + return type; + } + } + } + + return -1; +} + +static int +virLengthForPromptString(const char *str) +{ + int len = strlen(str); + + while (len > 0 && (str[len-1] == ' ' || str[len-1] == ':')) + --len; + + return len; +} + +/* check session host keys + * + * this function checks the known host database and verifies the key + * errors are raised in this func + * + * return value: 0 on success, -1 on error + */ +static int +virNetLibsshCheckHostKey(virNetLibsshSessionPtr sess) +{ + int state; + char *keyhashstr; + const char *errmsg; + + if (sess->hostKeyVerify == VIR_NET_LIBSSH_HOSTKEY_VERIFY_IGNORE) + return 0; + + state = ssh_is_server_known(sess->session); + + switch (state) { + case SSH_SERVER_KNOWN_OK: + /* host key matches */ + return 0; + + case SSH_SERVER_FOUND_OTHER: + case SSH_SERVER_KNOWN_CHANGED: + keyhashstr = virSshServerKeyAsString(sess); + if (!keyhashstr) + return -1; + + /* host key verification failed */ + virReportError(VIR_ERR_AUTH_FAILED, + _("!!! SSH HOST KEY VERIFICATION FAILED !!!: " + "Identity of host '%s:%d' differs from stored identity. " + "Please verify the new host key '%s' to avoid possible " + "man in the middle attack. The key is stored in '%s'."), + sess->hostname, sess->port, + keyhashstr, sess->knownHostsFile); + + ssh_string_free_char(keyhashstr); + return -1; + + case SSH_SERVER_FILE_NOT_FOUND: + case SSH_SERVER_NOT_KNOWN: + /* key was not found, query to add it to database */ + if (sess->hostKeyVerify == VIR_NET_LIBSSH_HOSTKEY_VERIFY_NORMAL) { + virConnectCredential askKey; + char *tmp; + + /* ask to add the key */ + if (!sess->cred || !sess->cred->cb) { + virReportError(VIR_ERR_LIBSSH, "%s", + _("No user interaction callback provided: " + "Can't verify the session host key")); + return -1; + } + + /* prepare data for the callback */ + memset(&askKey, 0, sizeof(virConnectCredential)); + askKey.type = virCredTypeForPrompt(sess->cred, 1 /* echo */); + + if (askKey.type == -1) { + virReportError(VIR_ERR_LIBSSH, "%s", + _("no suitable callback for host key " + "verification")); + return -1; + } + + keyhashstr = virSshServerKeyAsString(sess); + if (!keyhashstr) + return -1; + + if (virAsprintf((char **)&askKey.prompt, + _("Accept SSH host key with hash '%s' for " + "host '%s:%d' (%s/%s)?"), + keyhashstr, + sess->hostname, sess->port, + "y", "n") < 0) { + ssh_string_free_char(keyhashstr); + return -1; + } + + if (sess->cred->cb(&askKey, 1, sess->cred->cbdata)) { + virReportError(VIR_ERR_LIBSSH, "%s", + _("failed to retrieve decision to accept " + "host key")); + tmp = (char*)askKey.prompt; + VIR_FREE(tmp); + ssh_string_free_char(keyhashstr); + return -1; + } + + tmp = (char*)askKey.prompt; + VIR_FREE(tmp); + + if (!askKey.result || + STRCASENEQ(askKey.result, "y")) { + virReportError(VIR_ERR_LIBSSH, + _("SSH host key for '%s' (%s) was not accepted"), + sess->hostname, keyhashstr); + ssh_string_free_char(keyhashstr); + VIR_FREE(askKey.result); + return -1; + } + ssh_string_free_char(keyhashstr); + VIR_FREE(askKey.result); + } + + /* write the host key file */ + if (ssh_write_knownhost(sess->session) < 0) { + errmsg = ssh_get_error(sess->session); + virReportError(VIR_ERR_LIBSSH, + _("failed to write known_host file '%s': %s"), + sess->knownHostsFile, + errmsg); + return -1; + } + /* key was accepted and added */ + return 0; + + case SSH_SERVER_ERROR: + errmsg = ssh_get_error(sess->session); + virReportError(VIR_ERR_LIBSSH, + _("failed to validate SSH host key: %s"), + errmsg); + return -1; + + default: /* should never happen (tm) */ + virReportError(VIR_ERR_LIBSSH, "%s", _("Unknown error value")); + return -1; + } + + return -1; +} + +/* callback for ssh_pki_import_privkey_file, used to get the passphrase + * of a private key + */ +static int +virNetLibsshAuthenticatePrivkeyCb(const char *prompt, char *buf, size_t len, + int echo, int verify ATTRIBUTE_UNUSED, + void *userdata)

+{ + virNetLibsshSessionPtr sess = userdata; + virConnectCredential retr_passphrase; + virBuffer buff = VIR_BUFFER_INITIALIZER; + char *p; + + /* request user's key password */ + if (!sess->cred || !sess->cred->cb) { + virReportError(VIR_ERR_LIBSSH, "%s", + _("No user interaction callback provided: " + "Can't retrieve private key passphrase")); + return -1; + } + + virBufferAdd(&buff, prompt, virLengthForPromptString(prompt)); + + if (virBufferCheckError(&buff) < 0) { + virBufferFreeAndReset(&buff);

+ return -1; + } + + memset(&retr_passphrase, 0, sizeof(virConnectCredential)); + retr_passphrase.type = virCredTypeForPrompt(sess->cred, echo); + retr_passphrase.prompt = virBufferCurrentContent(&buff);

+ + if (retr_passphrase.type == -1) { + virBufferFreeAndReset(&buff);

+ virReportError(VIR_ERR_LIBSSH, "%s", + _("no suitable callback for input of key passphrase")); + return -1; + } + + if (sess->cred->cb(&retr_passphrase, 1, sess->cred->cbdata)) { + virBufferFreeAndReset(&buff);

+ virReportError(VIR_ERR_LIBSSH, "%s", + _("failed to retrieve private key passphrase: " + "callback has failed")); + return -1; + } + + virBufferFreeAndReset(&buff);

+ + p = virStrncpy(buf, retr_passphrase.result, + retr_passphrase.resultlen, len); + VIR_FREE(retr_passphrase.result);

+ if (!p) { + virReportError(VIR_ERR_LIBSSH, "%s", + _("authentication buffer too long for provided " + "passphrase"));

+ return -1; + } + + return 0; +} + +/* perform private key authentication + * + * returns SSH_AUTH_* values + */ +static int +virNetLibsshAuthenticatePrivkey(virNetLibsshSessionPtr sess, + virNetLibsshAuthMethodPtr priv) +{ + int err; + int ret; + char *tmp = NULL; + ssh_key public_key = NULL; + ssh_key private_key = NULL; + + VIR_DEBUG("sess=%p", sess); + + /* try open the key with the password set, first */ + ret = ssh_pki_import_privkey_file(priv->filename, priv->password, + virNetLibsshAuthenticatePrivkeyCb, + sess, &private_key); + if (ret == SSH_EOF) { + virReportError(VIR_ERR_AUTH_FAILED, + _("error while reading private key '%s'"), + priv->filename);

+ err = SSH_AUTH_ERROR; + goto error; + } else if (ret == SSH_ERROR) { + virReportError(VIR_ERR_AUTH_FAILED, + _("error while opening private key '%s', wrong " + "passphrase?"), + priv->filename);

+ err = SSH_AUTH_ERROR; + goto error; + } + + if (virAsprintf(&tmp, "%s.pub", priv->filename) < 0) { + err = SSH_AUTH_ERROR; + goto error; + } + + /* try to open the public part of the private key */ + ret = ssh_pki_import_pubkey_file(tmp, &public_key); + if (ret == SSH_ERROR) { + virReportError(VIR_ERR_AUTH_FAILED, + _("error while reading public key '%s'"), + tmp); + err = SSH_AUTH_ERROR; + goto error; + } else if (ret == SSH_EOF) { + /* create the public key from the private key */ + ret = ssh_pki_export_privkey_to_pubkey(private_key, &public_key); + if (ret == SSH_ERROR) { + virReportError(VIR_ERR_AUTH_FAILED, + _("cannot export the public key from the " + "private key '%s'"), + tmp); + err = SSH_AUTH_ERROR; + goto error; + } + } + + VIR_FREE(tmp); + + ret = ssh_userauth_try_publickey(sess->session, NULL, public_key); + if (ret != SSH_AUTH_SUCCESS) { + err = SSH_AUTH_DENIED; + goto error; + } + + ret = ssh_userauth_publickey(sess->session, NULL, private_key); + if (ret != SSH_AUTH_SUCCESS) { + err = SSH_AUTH_DENIED; + goto error; + } + + ssh_key_free(private_key); + ssh_key_free(public_key); + + return SSH_AUTH_SUCCESS; + + error: + if (private_key) + ssh_key_free(private_key); + if (public_key) + ssh_key_free(public_key); + VIR_FREE(tmp); + return err; +} + + +/* perform password authentication, either directly or request the password + * + * returns SSH_AUTH_* values + */ +static int +virNetLibsshAuthenticatePassword(virNetLibsshSessionPtr sess, + virNetLibsshAuthMethodPtr priv) +{ + char *password = NULL; + const char *errmsg; + int ret = -1; + + VIR_DEBUG("sess=%p", sess); + + if (priv->password) { + /* tunelled password authentication */ + if ((ret = ssh_userauth_password(sess->session, NULL, + priv->password)) == 0) { + ret = SSH_AUTH_SUCCESS; + goto cleanup; + } + } else { + /* password authentication with interactive password request */ + if (!sess->cred || !sess->cred->cb) { + virReportError(VIR_ERR_LIBSSH, "%s", + _("Can't perform authentication: " + "Authentication callback not provided")); + ret = SSH_AUTH_ERROR; + goto cleanup; + } + + /* Try the authenticating the set amount of times. The server breaks the + * connection if maximum number of bad auth tries is exceeded */ + while (true) { + if (!(password = virAuthGetPasswordPath(sess->authPath, sess->cred, + "ssh", sess->username, + sess->hostname))) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("failed to retrieve password")); + ret = SSH_AUTH_ERROR; + goto cleanup; + } + + /* tunelled password authentication */ + if ((ret = ssh_userauth_password(sess->session, NULL, + password)) == 0) { + ret = SSH_AUTH_SUCCESS; + goto cleanup; + } + + VIR_FREE(password);

+ + if (ret != SSH_AUTH_DENIED) + break; + } + } + + /* error path */ + errmsg = ssh_get_error(sess->session); + virReportError(VIR_ERR_AUTH_FAILED, + _("authentication failed: %s"), errmsg); + + return ret; + + cleanup: + VIR_FREE(password);

+ return ret; +} + +/* perform keyboard interactive authentication + * + * returns SSH_AUTH_* values + */ +static int +virNetLibsshAuthenticateKeyboardInteractive(virNetLibsshSessionPtr sess, + virNetLibsshAuthMethodPtr priv) +{ + int ret; + const char *errmsg; + int try = 0; + + /* request user's key password */ + if (!sess->cred || !sess->cred->cb) { + virReportError(VIR_ERR_LIBSSH, "%s", + _("No user interaction callback provided: " + "Can't get input from keyboard interactive " + "authentication")); + return SSH_AUTH_ERROR; + } + + again: + ret = ssh_userauth_kbdint(sess->session, NULL, NULL); + while (ret == SSH_AUTH_INFO) { + const char *name, *instruction; + int nprompts, iprompt; + virBuffer buff = VIR_BUFFER_INITIALIZER; + + name = ssh_userauth_kbdint_getname(sess->session); + instruction = ssh_userauth_kbdint_getinstruction(sess->session); + nprompts = ssh_userauth_kbdint_getnprompts(sess->session); + + /* compose the main buffer with name and instruction, if present */ + if (name && name[0]) + virBufferAddStr(&buff, name); + if (instruction && instruction[0]) { + if (virBufferUse(&buff) > 0) + virBufferAddChar(&buff, '\n'); + virBufferAddStr(&buff, instruction); + } + + if (virBufferCheckError(&buff) < 0) { + virBufferFreeAndReset(&buff); + return -1; + } + + for (iprompt = 0; iprompt < nprompts; iprompt++) { + virConnectCredential retr_passphrase; + const char *promptStr; + char echo; + virBuffer prompt = VIR_BUFFER_INITIALIZER; + + /* get the prompt, stripping the trailing newlines and spaces */ + promptStr = ssh_userauth_kbdint_getprompt(sess->session, iprompt, + &echo); + + /* compose the instruction buffer with this prompt */ + if (virBufferUse(&buff) > 0) { + virBufferAddBuffer(&prompt, &buff); + virBufferAddChar(&prompt, '\n'); + } + virBufferAdd(&prompt, promptStr, + virLengthForPromptString(promptStr)); + + if (virBufferCheckError(&prompt) < 0) { + virBufferFreeAndReset(&buff); + virBufferFreeAndReset(&prompt); + return -1; + } + + memset(&retr_passphrase, 0, sizeof(virConnectCredential)); + retr_passphrase.type = virCredTypeForPrompt(sess->cred, echo); + retr_passphrase.prompt = virBufferCurrentContent(&prompt);

+ + if (retr_passphrase.type == -1) { + virBufferFreeAndReset(&buff); + virBufferFreeAndReset(&prompt);

+ virReportError(VIR_ERR_LIBSSH, "%s", + _("no suitable callback for input of key " + "passphrase")); + return SSH_AUTH_ERROR; + } + + if (sess->cred->cb(&retr_passphrase, 1, sess->cred->cbdata)) { + virBufferFreeAndReset(&buff); + virBufferFreeAndReset(&prompt);

+ virReportError(VIR_ERR_LIBSSH, "%s", + _("failed to retrieve keyboard interactive " + "result: callback has failed")); + return SSH_AUTH_ERROR; + } + + ret = ssh_userauth_kbdint_setanswer(sess->session, iprompt, + retr_passphrase.result); + virBufferFreeAndReset(&prompt); + VIR_FREE(retr_passphrase.result);

+ if (ret < 0) { + virBufferFreeAndReset(&buff); + errmsg = ssh_get_error(sess->session); + virReportError(VIR_ERR_AUTH_FAILED, + _("authentication failed: %s"), errmsg); + return ret; + } + } + + virBufferFreeAndReset(&buff); + + ret = ssh_userauth_kbdint(sess->session, NULL, NULL); + ++try; + if (ret == SSH_AUTH_DENIED && (priv->tries < 0 || try < priv->tries)) + goto again; + } + + if (ret == SSH_AUTH_ERROR) { + /* error path */ + errmsg = ssh_get_error(sess->session); + virReportError(VIR_ERR_AUTH_FAILED, + _("authentication failed: %s"), errmsg); + } + + return ret; +} + +/* select auth method and authenticate */ +static int +virNetLibsshAuthenticate(virNetLibsshSessionPtr sess) +{ + virNetLibsshAuthMethodPtr auth; + bool auth_failed = false; + const char *errmsg; + int ret; + int methods; + + VIR_DEBUG("sess=%p", sess); + + /* At this point, we can assume there is at least one + * authentication method set -- virNetLibsshValidateConfig + * already checked that. + */ + + /* try to authenticate */ + ret = ssh_userauth_none(sess->session, NULL); + if (ret == SSH_AUTH_ERROR) { + errmsg = ssh_get_error(sess->session); + virReportError(VIR_ERR_LIBSSH, + _("Failed to authenticate as 'none': %s"), + errmsg); + return -1; + } + + /* obtain list of supported auth methods */ + methods = ssh_userauth_list(sess->session, NULL); + + if (methods & SSH_AUTH_METHOD_PUBLICKEY) { + /* try to authenticate using ssh-agent first */ + auth = sess->auths[VIR_NET_LIBSSH_AUTH_AGENT]; + if (auth) { + ret = ssh_userauth_publickey_auto(sess->session, NULL, NULL); + if (ret == SSH_AUTH_ERROR) { + errmsg = ssh_get_error(sess->session); + virReportError(VIR_ERR_LIBSSH, + _("failed to authenticate using agent: %s"), + errmsg); + return -1; + } else if (ret == SSH_AUTH_SUCCESS) { + /* authenticated */ + return 0; + } + } + + /* try to authenticate using the provided ssh key, if any */ + auth = sess->auths[VIR_NET_LIBSSH_AUTH_PRIVKEY]; + if (auth) { + ret = virNetLibsshAuthenticatePrivkey(sess, auth); + if (ret == SSH_AUTH_ERROR) { + /* virReportError is called already */ + return -1; + } else if (ret == SSH_AUTH_SUCCESS) { + /* authenticated */ + return 0; + } + } + + auth_failed = true; + } + + if (methods & SSH_AUTH_METHOD_INTERACTIVE) { + /* try to authenticate using the keyboard interactive way */ + auth = sess->auths[VIR_NET_LIBSSH_AUTH_KEYBOARD_INTERACTIVE]; + if (auth) { + ret = virNetLibsshAuthenticateKeyboardInteractive(sess, auth); + if (ret == SSH_AUTH_ERROR) { + /* virReportError is called already */ + return -1; + } else if (ret == SSH_AUTH_SUCCESS) { + /* authenticated */ + return 0; + } + } + + auth_failed = true; + } + + if (methods & SSH_AUTH_METHOD_PASSWORD) { + /* try to authenticate with password */ + auth = sess->auths[VIR_NET_LIBSSH_AUTH_PASSWORD]; + if (auth) { + ret = virNetLibsshAuthenticatePassword(sess, auth); + if (ret == SSH_AUTH_ERROR) { + /* virReportError is called already */ + return -1; + } else if (ret == SSH_AUTH_SUCCESS) { + /* authenticated */ + return 0; + } + } + + auth_failed = true; + } + + if (!auth_failed) { + virReportError(VIR_ERR_AUTH_FAILED, "%s", + _("None of the requested authentication methods " + "are supported by the server")); + } else { + virReportError(VIR_ERR_AUTH_FAILED, "%s", + _("All provided authentication methods with credentials " + "were rejected by the server")); + } + + return -1; +} + +/* open channel */ +static int +virNetLibsshOpenChannel(virNetLibsshSessionPtr sess) +{ + const char *errmsg; + + sess->channel = ssh_channel_new(sess->session); + if (!sess->channel) { + errmsg = ssh_get_error(sess->session); + virReportError(VIR_ERR_LIBSSH, + _("failed to create libssh channel: %s"), + errmsg); + return -1; + } + + if (ssh_channel_open_session(sess->channel) != SSH_OK) { + errmsg = ssh_get_error(sess->session); + virReportError(VIR_ERR_LIBSSH, + _("failed to open ssh channel: %s"), + errmsg); + return -1; + } + + if (ssh_channel_request_exec(sess->channel, sess->channelCommand) != SSH_OK) { + errmsg = ssh_get_error(sess->session); + virReportError(VIR_ERR_LIBSSH, + _("failed to execute command '%s': %s"), + sess->channelCommand, + errmsg); + return -1; + } + + /* nonblocking mode */ + ssh_channel_set_blocking(sess->channel, 0); + + /* channel open */ + return 0; +} + +/* validate if all required parameters are configured */ +static int +virNetLibsshValidateConfig(virNetLibsshSessionPtr sess) +{ + size_t i; + bool has_auths = false; + + for (i = 0; i < ARRAY_CARDINALITY(sess->auths); ++i) { + if (sess->auths[i]) { + has_auths = true; + break; + } + } + if (!has_auths) { + virReportError(VIR_ERR_LIBSSH, "%s", + _("No authentication methods and credentials " + "provided")); + return -1; + } + + if (!sess->channelCommand) { + virReportError(VIR_ERR_LIBSSH, "%s", + _("No channel command provided")); + return -1; + } + + if (sess->hostKeyVerify != VIR_NET_LIBSSH_HOSTKEY_VERIFY_IGNORE) { + if (!sess->hostname) { + virReportError(VIR_ERR_LIBSSH, "%s", + _("Hostname is needed for host key verification")); + return -1; + } + } + + /* everything ok */ + return 0; +} + +/* ### PUBLIC API ### */ +int +virNetLibsshSessionAuthSetCallback(virNetLibsshSessionPtr sess, + virConnectAuthPtr auth) +{ + virObjectLock(sess); + sess->cred = auth; + virObjectUnlock(sess); + return 0; +} + +void +virNetLibsshSessionAuthReset(virNetLibsshSessionPtr sess) +{ + virObjectLock(sess); + virNetLibsshSessionAuthMethodsFree(sess); + virObjectUnlock(sess); +} + +int +virNetLibsshSessionAuthAddPasswordAuth(virNetLibsshSessionPtr sess, + virURIPtr uri) +{ + virNetLibsshAuthMethodPtr auth; + + if (uri) { + VIR_FREE(sess->authPath); + + if (virAuthGetConfigFilePathURI(uri, &sess->authPath) < 0) + goto error; + } + + virObjectLock(sess); + + if (!(auth = virNetLibsshSessionAuthMethodNew(sess, + VIR_NET_LIBSSH_AUTH_PASSWORD))) + goto error; + + virObjectUnlock(sess); + return 0; + + error: + virObjectUnlock(sess); + return -1;

+} + +int +virNetLibsshSessionAuthAddAgentAuth(virNetLibsshSessionPtr sess) +{ + virNetLibsshAuthMethodPtr auth; + + virObjectLock(sess); + + if (!(auth = virNetLibsshSessionAuthMethodNew(sess, + VIR_NET_LIBSSH_AUTH_AGENT))) + goto error; + + virObjectUnlock(sess); + return 0; + + error: + virObjectUnlock(sess); + return -1;

+} + +int +virNetLibsshSessionAuthAddPrivKeyAuth(virNetLibsshSessionPtr sess, + const char *keyfile, + const char *password) +{ + virNetLibsshAuthMethodPtr auth; + + char *pass = NULL; + char *file = NULL; + + if (!keyfile) { + virReportError(VIR_ERR_LIBSSH, "%s", + _("Key file path must be provided " + "for private key authentication")); + return -1; + } + + virObjectLock(sess); + + if (VIR_STRDUP(file, keyfile) < 0 || + VIR_STRDUP(pass, password) < 0) + goto error; + + if (!(auth = virNetLibsshSessionAuthMethodNew(sess, + VIR_NET_LIBSSH_AUTH_PRIVKEY))) + goto error; + + auth->password = pass; + auth->filename = file; + + virObjectUnlock(sess); + return 0; + + error: + VIR_FREE(pass); + VIR_FREE(file); + virObjectUnlock(sess); + return -1; +} + +int +virNetLibsshSessionAuthAddKeyboardAuth(virNetLibsshSessionPtr sess, + int tries) +{ + virNetLibsshAuthMethodPtr auth; + + virObjectLock(sess); + + if (!(auth = virNetLibsshSessionAuthMethodNew(sess, + VIR_NET_LIBSSH_AUTH_KEYBOARD_INTERACTIVE))) + goto error; + + auth->tries = tries; + + virObjectUnlock(sess); + return 0; + + error: + virObjectUnlock(sess); + return -1;

+ +} + +int +virNetLibsshSessionSetChannelCommand(virNetLibsshSessionPtr sess, + const char *command) +{ + int ret = 0; + virObjectLock(sess); + + VIR_FREE(sess->channelCommand); + + if (VIR_STRDUP(sess->channelCommand, command) < 0) + ret = -1; + + virObjectUnlock(sess); + return ret; +} + +int +virNetLibsshSessionSetHostKeyVerification(virNetLibsshSessionPtr sess, + const char *hostname, + int port, + const char *hostsfile, + virNetLibsshHostkeyVerify opt) +{ + virObjectLock(sess); + + sess->port = port; + sess->hostKeyVerify = opt; + + VIR_FREE(sess->hostname); + + if (VIR_STRDUP(sess->hostname, hostname) < 0) + goto error; + + /* set the hostname */ + if (ssh_options_set(sess->session, SSH_OPTIONS_HOST, sess->hostname) < 0) + goto error; + + /* set the port */ + if (port > 0) { + unsigned int portU = port; + + if (ssh_options_set(sess->session, SSH_OPTIONS_PORT, &portU) < 0) + goto error; + } + + /* set the known hosts file */ + if (ssh_options_set(sess->session, SSH_OPTIONS_KNOWNHOSTS, hostsfile) < 0) + goto error; + + VIR_FREE(sess->knownHostsFile); + if (VIR_STRDUP(sess->knownHostsFile, hostsfile) < 0) + goto error; + + virObjectUnlock(sess); + return 0; + + error: + virObjectUnlock(sess); + return -1; +} + +/* allocate and initialize a libssh session object */ +virNetLibsshSessionPtr virNetLibsshSessionNew(const char *username) +{ + virNetLibsshSessionPtr sess = NULL; + + if (virNetLibsshSessionInitialize() < 0) + goto error; + + if (!(sess = virObjectLockableNew(virNetLibsshSessionClass))) + goto error; + + /* initialize session data */ + if (!(sess->session = ssh_new())) { + virReportError(VIR_ERR_LIBSSH, "%s", + _("Failed to initialize libssh session")); + goto error; + } + + if (VIR_STRDUP(sess->username, username) < 0) + goto error; + + VIR_DEBUG("virNetLibsshSessionPtr: %p, ssh_session: %p", + sess, sess->session); + + /* set blocking mode for libssh until handshake is complete */ + ssh_set_blocking(sess->session, 1); + + if (ssh_options_set(sess->session, SSH_OPTIONS_USER, sess->username) < 0) + goto error; + + /* default states for config variables */ + sess->state = VIR_NET_LIBSSH_STATE_NEW; + sess->hostKeyVerify = VIR_NET_LIBSSH_HOSTKEY_VERIFY_IGNORE; + + return sess; + + error: + virObjectUnref(sess); + return NULL; +} + +int +virNetLibsshSessionConnect(virNetLibsshSessionPtr sess, + int sock) +{ + int ret; + const char *errmsg; + + VIR_DEBUG("sess=%p, sock=%d", sess, sock); + + if (!sess || sess->state != VIR_NET_LIBSSH_STATE_NEW) { + virReportError(VIR_ERR_LIBSSH, "%s", + _("Invalid virNetLibsshSessionPtr")); + return -1; + } + + virObjectLock(sess); + + /* check if configuration is valid */ + if ((ret = virNetLibsshValidateConfig(sess)) < 0) + goto error; + + /* read ~/.ssh/config */ + if ((ret = ssh_options_parse_config(sess->session, NULL)) < 0) + goto error; + + /* set the socket FD for the libssh session */ + if ((ret = ssh_options_set(sess->session, SSH_OPTIONS_FD, &sock)) < 0)

+ goto error; + + /* open session */ + ret = ssh_connect(sess->session); + /* libssh is in blocking mode, so EAGAIN will never happen */ + if (ret < 0) { + errmsg = ssh_get_error(sess->session); + virReportError(VIR_ERR_NO_CONNECT, + _("SSH session handshake failed: %s"), + errmsg); + goto error; + } + + /* verify the SSH host key */ + if ((ret = virNetLibsshCheckHostKey(sess)) != 0) + goto error; + + /* authenticate */ + if ((ret = virNetLibsshAuthenticate(sess)) != 0) + goto error; + + /* open channel */ + if ((ret = virNetLibsshOpenChannel(sess)) != 0) + goto error; + + /* all set */ + /* switch to nonblocking mode and return */ + ssh_set_blocking(sess->session, 0); + sess->state = VIR_NET_LIBSSH_STATE_HANDSHAKE_COMPLETE; + + virObjectUnlock(sess); + return ret; + + error: + sess->state = VIR_NET_LIBSSH_STATE_ERROR; + virObjectUnlock(sess); + return ret; +} + +/* do a read from a ssh channel, used instead of normal read on socket */ +ssize_t +virNetLibsshChannelRead(virNetLibsshSessionPtr sess, + char *buf, + size_t len) +{ + int ret = -1; + ssize_t read_n = 0; + + virObjectLock(sess); + + if (sess->state != VIR_NET_LIBSSH_STATE_HANDSHAKE_COMPLETE) { + if (sess->state == VIR_NET_LIBSSH_STATE_ERROR_REMOTE) + virReportError(VIR_ERR_LIBSSH, + _("Remote program terminated " + "with non-zero code: %d"), + sess->channelCommandReturnValue); + else + virReportError(VIR_ERR_LIBSSH, "%s", + _("Tried to write socket in error state")); + + virObjectUnlock(sess); + return -1; + } + + if (sess->bufUsed > 0) { + /* copy the rest (or complete) internal buffer to the output buffer */ + memcpy(buf, + sess->rbuf + sess->bufStart, + len > sess->bufUsed ? sess->bufUsed : len); + + if (len >= sess->bufUsed) { + read_n = sess->bufUsed; + + sess->bufStart = 0; + sess->bufUsed = 0; + } else { + read_n = len; + sess->bufUsed -= len; + sess->bufStart += len; + + goto success; + } + } + + /* continue reading into the buffer supplied */ + if (read_n < len) { + ret = ssh_channel_read(sess->channel, + buf + read_n, + len - read_n, + 0); + + if (ret == SSH_AGAIN || (ret == 0 && !ssh_channel_is_eof(sess->channel))) + goto success; + + if (ret < 0) + goto error; + + read_n += ret; + } + + /* try to read something into the internal buffer */ + if (sess->bufUsed == 0) { + ret = ssh_channel_read(sess->channel, + sess->rbuf, + VIR_NET_LIBSSH_BUFFER_SIZE, + 0); + + if (ret == SSH_AGAIN || (ret == 0 && !ssh_channel_is_eof(sess->channel))) + goto success; + + if (ret < 0) + goto error; + + sess->bufUsed = ret; + sess->bufStart = 0; + } + + if (read_n == 0) { + /* get rid of data in stderr stream */ + ret = ssh_channel_read(sess->channel, + sess->rbuf, + VIR_NET_LIBSSH_BUFFER_SIZE - 1, + 1); + if (ret > 0) { + sess->rbuf[ret] = '\0'; + VIR_DEBUG("flushing stderr, data='%s'", sess->rbuf); + } + } + + if (ssh_channel_is_eof(sess->channel)) { + if (ssh_channel_get_exit_status(sess->channel)) { + virReportError(VIR_ERR_LIBSSH, + _("Remote command terminated with non-zero code: %d"), + ssh_channel_get_exit_status(sess->channel)); + sess->channelCommandReturnValue = ssh_channel_get_exit_status(sess->channel); + sess->state = VIR_NET_LIBSSH_STATE_ERROR_REMOTE; + virObjectUnlock(sess); + return -1; + } + + sess->state = VIR_NET_LIBSSH_STATE_CLOSED; + virObjectUnlock(sess); + return -1; + } + + success: + virObjectUnlock(sess); + return read_n; + + error: + sess->state = VIR_NET_LIBSSH_STATE_ERROR; + virObjectUnlock(sess); + return ret; +} + +ssize_t +virNetLibsshChannelWrite(virNetLibsshSessionPtr sess, + const char *buf, + size_t len) +{ + ssize_t ret; + + virObjectLock(sess); + + if (sess->state != VIR_NET_LIBSSH_STATE_HANDSHAKE_COMPLETE) { + if (sess->state == VIR_NET_LIBSSH_STATE_ERROR_REMOTE) + virReportError(VIR_ERR_LIBSSH, + _("Remote program terminated with non-zero code: %d"), + sess->channelCommandReturnValue); + else + virReportError(VIR_ERR_LIBSSH, "%s", + _("Tried to write socket in error state")); + ret = -1; + goto cleanup; + } + + if (ssh_channel_is_eof(sess->channel)) { + if (ssh_channel_get_exit_status(sess->channel)) { + virReportError(VIR_ERR_LIBSSH, + _("Remote program terminated with non-zero code: %d"), + ssh_channel_get_exit_status(sess->channel)); + sess->state = VIR_NET_LIBSSH_STATE_ERROR_REMOTE; + sess->channelCommandReturnValue = ssh_channel_get_exit_status(sess->channel); + + ret = -1; + goto cleanup; + } + + sess->state = VIR_NET_LIBSSH_STATE_CLOSED; + ret = -1; + goto cleanup; + } + + ret = ssh_channel_write(sess->channel, buf, len); + if (ret == SSH_AGAIN) { + ret = 0; + goto cleanup; + } + + if (ret < 0) { + const char *msg; + sess->state = VIR_NET_LIBSSH_STATE_ERROR; + msg = ssh_get_error(sess->session); + virReportError(VIR_ERR_LIBSSH, + _("write failed: %s"), msg); + } + + cleanup: + virObjectUnlock(sess); + return ret; +} + +bool +virNetLibsshSessionHasCachedData(virNetLibsshSessionPtr sess) +{ + bool ret; + + if (!sess) + return false; + + virObjectLock(sess); + + ret = sess->bufUsed > 0; + + virObjectUnlock(sess); + return ret; +}