| /* |
| * Secure Shell (ssh) backend for QEMU. |
| * |
| * Copyright (C) 2013 Red Hat Inc., Richard W.M. Jones <rjones@redhat.com> |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a copy |
| * of this software and associated documentation files (the "Software"), to deal |
| * in the Software without restriction, including without limitation the rights |
| * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| * copies of the Software, and to permit persons to whom the Software is |
| * furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included in |
| * all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| * THE SOFTWARE. |
| */ |
| |
| #include "qemu/osdep.h" |
| |
| #include <libssh/libssh.h> |
| #include <libssh/sftp.h> |
| |
| #include "block/block_int.h" |
| #include "block/qdict.h" |
| #include "qapi/error.h" |
| #include "qemu/error-report.h" |
| #include "qemu/module.h" |
| #include "qemu/option.h" |
| #include "qemu/ctype.h" |
| #include "qemu/cutils.h" |
| #include "qemu/sockets.h" |
| #include "qemu/uri.h" |
| #include "qapi/qapi-visit-sockets.h" |
| #include "qapi/qapi-visit-block-core.h" |
| #include "qapi/qmp/qdict.h" |
| #include "qapi/qmp/qstring.h" |
| #include "qapi/qobject-input-visitor.h" |
| #include "qapi/qobject-output-visitor.h" |
| #include "trace.h" |
| |
| /* |
| * TRACE_LIBSSH=<level> enables tracing in libssh itself. |
| * The meaning of <level> is described here: |
| * http://api.libssh.org/master/group__libssh__log.html |
| */ |
| #define TRACE_LIBSSH 0 /* see: SSH_LOG_* */ |
| |
| typedef struct BDRVSSHState { |
| /* Coroutine. */ |
| CoMutex lock; |
| |
| /* SSH connection. */ |
| int sock; /* socket */ |
| ssh_session session; /* ssh session */ |
| sftp_session sftp; /* sftp session */ |
| sftp_file sftp_handle; /* sftp remote file handle */ |
| |
| /* |
| * File attributes at open. We try to keep the .size field |
| * updated if it changes (eg by writing at the end of the file). |
| */ |
| sftp_attributes attrs; |
| |
| InetSocketAddress *inet; |
| |
| /* Used to warn if 'flush' is not supported. */ |
| bool unsafe_flush_warning; |
| |
| /* |
| * Store the user name for ssh_refresh_filename() because the |
| * default depends on the system you are on -- therefore, when we |
| * generate a filename, it should always contain the user name we |
| * are actually using. |
| */ |
| char *user; |
| } BDRVSSHState; |
| |
| static void ssh_state_init(BDRVSSHState *s) |
| { |
| memset(s, 0, sizeof *s); |
| s->sock = -1; |
| qemu_co_mutex_init(&s->lock); |
| } |
| |
| static void ssh_state_free(BDRVSSHState *s) |
| { |
| g_free(s->user); |
| |
| if (s->attrs) { |
| sftp_attributes_free(s->attrs); |
| } |
| if (s->sftp_handle) { |
| sftp_close(s->sftp_handle); |
| } |
| if (s->sftp) { |
| sftp_free(s->sftp); |
| } |
| if (s->session) { |
| ssh_disconnect(s->session); |
| ssh_free(s->session); /* This frees s->sock */ |
| } |
| } |
| |
| static void GCC_FMT_ATTR(3, 4) |
| session_error_setg(Error **errp, BDRVSSHState *s, const char *fs, ...) |
| { |
| va_list args; |
| char *msg; |
| |
| va_start(args, fs); |
| msg = g_strdup_vprintf(fs, args); |
| va_end(args); |
| |
| if (s->session) { |
| const char *ssh_err; |
| int ssh_err_code; |
| |
| /* This is not an errno. See <libssh/libssh.h>. */ |
| ssh_err = ssh_get_error(s->session); |
| ssh_err_code = ssh_get_error_code(s->session); |
| error_setg(errp, "%s: %s (libssh error code: %d)", |
| msg, ssh_err, ssh_err_code); |
| } else { |
| error_setg(errp, "%s", msg); |
| } |
| g_free(msg); |
| } |
| |
| static void GCC_FMT_ATTR(3, 4) |
| sftp_error_setg(Error **errp, BDRVSSHState *s, const char *fs, ...) |
| { |
| va_list args; |
| char *msg; |
| |
| va_start(args, fs); |
| msg = g_strdup_vprintf(fs, args); |
| va_end(args); |
| |
| if (s->sftp) { |
| const char *ssh_err; |
| int ssh_err_code; |
| int sftp_err_code; |
| |
| /* This is not an errno. See <libssh/libssh.h>. */ |
| ssh_err = ssh_get_error(s->session); |
| ssh_err_code = ssh_get_error_code(s->session); |
| /* See <libssh/sftp.h>. */ |
| sftp_err_code = sftp_get_error(s->sftp); |
| |
| error_setg(errp, |
| "%s: %s (libssh error code: %d, sftp error code: %d)", |
| msg, ssh_err, ssh_err_code, sftp_err_code); |
| } else { |
| error_setg(errp, "%s", msg); |
| } |
| g_free(msg); |
| } |
| |
| static void sftp_error_trace(BDRVSSHState *s, const char *op) |
| { |
| const char *ssh_err; |
| int ssh_err_code; |
| int sftp_err_code; |
| |
| /* This is not an errno. See <libssh/libssh.h>. */ |
| ssh_err = ssh_get_error(s->session); |
| ssh_err_code = ssh_get_error_code(s->session); |
| /* See <libssh/sftp.h>. */ |
| sftp_err_code = sftp_get_error(s->sftp); |
| |
| trace_sftp_error(op, ssh_err, ssh_err_code, sftp_err_code); |
| } |
| |
| static int parse_uri(const char *filename, QDict *options, Error **errp) |
| { |
| URI *uri = NULL; |
| QueryParams *qp; |
| char *port_str; |
| int i; |
| |
| uri = uri_parse(filename); |
| if (!uri) { |
| return -EINVAL; |
| } |
| |
| if (g_strcmp0(uri->scheme, "ssh") != 0) { |
| error_setg(errp, "URI scheme must be 'ssh'"); |
| goto err; |
| } |
| |
| if (!uri->server || strcmp(uri->server, "") == 0) { |
| error_setg(errp, "missing hostname in URI"); |
| goto err; |
| } |
| |
| if (!uri->path || strcmp(uri->path, "") == 0) { |
| error_setg(errp, "missing remote path in URI"); |
| goto err; |
| } |
| |
| qp = query_params_parse(uri->query); |
| if (!qp) { |
| error_setg(errp, "could not parse query parameters"); |
| goto err; |
| } |
| |
| if(uri->user && strcmp(uri->user, "") != 0) { |
| qdict_put_str(options, "user", uri->user); |
| } |
| |
| qdict_put_str(options, "server.host", uri->server); |
| |
| port_str = g_strdup_printf("%d", uri->port ?: 22); |
| qdict_put_str(options, "server.port", port_str); |
| g_free(port_str); |
| |
| qdict_put_str(options, "path", uri->path); |
| |
| /* Pick out any query parameters that we understand, and ignore |
| * the rest. |
| */ |
| for (i = 0; i < qp->n; ++i) { |
| if (strcmp(qp->p[i].name, "host_key_check") == 0) { |
| qdict_put_str(options, "host_key_check", qp->p[i].value); |
| } |
| } |
| |
| query_params_free(qp); |
| uri_free(uri); |
| return 0; |
| |
| err: |
| if (uri) { |
| uri_free(uri); |
| } |
| return -EINVAL; |
| } |
| |
| static bool ssh_has_filename_options_conflict(QDict *options, Error **errp) |
| { |
| const QDictEntry *qe; |
| |
| for (qe = qdict_first(options); qe; qe = qdict_next(options, qe)) { |
| if (!strcmp(qe->key, "host") || |
| !strcmp(qe->key, "port") || |
| !strcmp(qe->key, "path") || |
| !strcmp(qe->key, "user") || |
| !strcmp(qe->key, "host_key_check") || |
| strstart(qe->key, "server.", NULL)) |
| { |
| error_setg(errp, "Option '%s' cannot be used with a file name", |
| qe->key); |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| static void ssh_parse_filename(const char *filename, QDict *options, |
| Error **errp) |
| { |
| if (ssh_has_filename_options_conflict(options, errp)) { |
| return; |
| } |
| |
| parse_uri(filename, options, errp); |
| } |
| |
| static int check_host_key_knownhosts(BDRVSSHState *s, Error **errp) |
| { |
| int ret; |
| #ifdef HAVE_LIBSSH_0_8 |
| enum ssh_known_hosts_e state; |
| int r; |
| ssh_key pubkey; |
| enum ssh_keytypes_e pubkey_type; |
| unsigned char *server_hash = NULL; |
| size_t server_hash_len; |
| char *fingerprint = NULL; |
| |
| state = ssh_session_is_known_server(s->session); |
| trace_ssh_server_status(state); |
| |
| switch (state) { |
| case SSH_KNOWN_HOSTS_OK: |
| /* OK */ |
| trace_ssh_check_host_key_knownhosts(); |
| break; |
| case SSH_KNOWN_HOSTS_CHANGED: |
| ret = -EINVAL; |
| r = ssh_get_server_publickey(s->session, &pubkey); |
| if (r == 0) { |
| r = ssh_get_publickey_hash(pubkey, SSH_PUBLICKEY_HASH_SHA256, |
| &server_hash, &server_hash_len); |
| pubkey_type = ssh_key_type(pubkey); |
| ssh_key_free(pubkey); |
| } |
| if (r == 0) { |
| fingerprint = ssh_get_fingerprint_hash(SSH_PUBLICKEY_HASH_SHA256, |
| server_hash, |
| server_hash_len); |
| ssh_clean_pubkey_hash(&server_hash); |
| } |
| if (fingerprint) { |
| error_setg(errp, |
| "host key (%s key with fingerprint %s) does not match " |
| "the one in known_hosts; this may be a possible attack", |
| ssh_key_type_to_char(pubkey_type), fingerprint); |
| ssh_string_free_char(fingerprint); |
| } else { |
| error_setg(errp, |
| "host key does not match the one in known_hosts; this " |
| "may be a possible attack"); |
| } |
| goto out; |
| case SSH_KNOWN_HOSTS_OTHER: |
| ret = -EINVAL; |
| error_setg(errp, |
| "host key for this server not found, another type exists"); |
| goto out; |
| case SSH_KNOWN_HOSTS_UNKNOWN: |
| ret = -EINVAL; |
| error_setg(errp, "no host key was found in known_hosts"); |
| goto out; |
| case SSH_KNOWN_HOSTS_NOT_FOUND: |
| ret = -ENOENT; |
| error_setg(errp, "known_hosts file not found"); |
| goto out; |
| case SSH_KNOWN_HOSTS_ERROR: |
| ret = -EINVAL; |
| error_setg(errp, "error while checking the host"); |
| goto out; |
| default: |
| ret = -EINVAL; |
| error_setg(errp, "error while checking for known server (%d)", state); |
| goto out; |
| } |
| #else /* !HAVE_LIBSSH_0_8 */ |
| int state; |
| |
| state = ssh_is_server_known(s->session); |
| trace_ssh_server_status(state); |
| |
| switch (state) { |
| case SSH_SERVER_KNOWN_OK: |
| /* OK */ |
| trace_ssh_check_host_key_knownhosts(); |
| break; |
| case SSH_SERVER_KNOWN_CHANGED: |
| ret = -EINVAL; |
| error_setg(errp, |
| "host key does not match the one in known_hosts; this " |
| "may be a possible attack"); |
| goto out; |
| case SSH_SERVER_FOUND_OTHER: |
| ret = -EINVAL; |
| error_setg(errp, |
| "host key for this server not found, another type exists"); |
| goto out; |
| case SSH_SERVER_FILE_NOT_FOUND: |
| ret = -ENOENT; |
| error_setg(errp, "known_hosts file not found"); |
| goto out; |
| case SSH_SERVER_NOT_KNOWN: |
| ret = -EINVAL; |
| error_setg(errp, "no host key was found in known_hosts"); |
| goto out; |
| case SSH_SERVER_ERROR: |
| ret = -EINVAL; |
| error_setg(errp, "server error"); |
| goto out; |
| default: |
| ret = -EINVAL; |
| error_setg(errp, "error while checking for known server (%d)", state); |
| goto out; |
| } |
| #endif /* !HAVE_LIBSSH_0_8 */ |
| |
| /* known_hosts checking successful. */ |
| ret = 0; |
| |
| out: |
| return ret; |
| } |
| |
| static unsigned hex2decimal(char ch) |
| { |
| if (ch >= '0' && ch <= '9') { |
| return (ch - '0'); |
| } else if (ch >= 'a' && ch <= 'f') { |
| return 10 + (ch - 'a'); |
| } else if (ch >= 'A' && ch <= 'F') { |
| return 10 + (ch - 'A'); |
| } |
| |
| return -1; |
| } |
| |
| /* Compare the binary fingerprint (hash of host key) with the |
| * host_key_check parameter. |
| */ |
| static int compare_fingerprint(const unsigned char *fingerprint, size_t len, |
| const char *host_key_check) |
| { |
| unsigned c; |
| |
| while (len > 0) { |
| while (*host_key_check == ':') |
| host_key_check++; |
| if (!qemu_isxdigit(host_key_check[0]) || |
| !qemu_isxdigit(host_key_check[1])) |
| return 1; |
| c = hex2decimal(host_key_check[0]) * 16 + |
| hex2decimal(host_key_check[1]); |
| if (c - *fingerprint != 0) |
| return c - *fingerprint; |
| fingerprint++; |
| len--; |
| host_key_check += 2; |
| } |
| return *host_key_check - '\0'; |
| } |
| |
| static int |
| check_host_key_hash(BDRVSSHState *s, const char *hash, |
| enum ssh_publickey_hash_type type, Error **errp) |
| { |
| int r; |
| ssh_key pubkey; |
| unsigned char *server_hash; |
| size_t server_hash_len; |
| |
| #ifdef HAVE_LIBSSH_0_8 |
| r = ssh_get_server_publickey(s->session, &pubkey); |
| #else |
| r = ssh_get_publickey(s->session, &pubkey); |
| #endif |
| if (r != SSH_OK) { |
| session_error_setg(errp, s, "failed to read remote host key"); |
| return -EINVAL; |
| } |
| |
| r = ssh_get_publickey_hash(pubkey, type, &server_hash, &server_hash_len); |
| ssh_key_free(pubkey); |
| if (r != 0) { |
| session_error_setg(errp, s, |
| "failed reading the hash of the server SSH key"); |
| return -EINVAL; |
| } |
| |
| r = compare_fingerprint(server_hash, server_hash_len, hash); |
| ssh_clean_pubkey_hash(&server_hash); |
| if (r != 0) { |
| error_setg(errp, "remote host key does not match host_key_check '%s'", |
| hash); |
| return -EPERM; |
| } |
| |
| return 0; |
| } |
| |
| static int check_host_key(BDRVSSHState *s, SshHostKeyCheck *hkc, Error **errp) |
| { |
| SshHostKeyCheckMode mode; |
| |
| if (hkc) { |
| mode = hkc->mode; |
| } else { |
| mode = SSH_HOST_KEY_CHECK_MODE_KNOWN_HOSTS; |
| } |
| |
| switch (mode) { |
| case SSH_HOST_KEY_CHECK_MODE_NONE: |
| return 0; |
| case SSH_HOST_KEY_CHECK_MODE_HASH: |
| if (hkc->u.hash.type == SSH_HOST_KEY_CHECK_HASH_TYPE_MD5) { |
| return check_host_key_hash(s, hkc->u.hash.hash, |
| SSH_PUBLICKEY_HASH_MD5, errp); |
| } else if (hkc->u.hash.type == SSH_HOST_KEY_CHECK_HASH_TYPE_SHA1) { |
| return check_host_key_hash(s, hkc->u.hash.hash, |
| SSH_PUBLICKEY_HASH_SHA1, errp); |
| } |
| g_assert_not_reached(); |
| break; |
| case SSH_HOST_KEY_CHECK_MODE_KNOWN_HOSTS: |
| return check_host_key_knownhosts(s, errp); |
| default: |
| g_assert_not_reached(); |
| } |
| |
| return -EINVAL; |
| } |
| |
| static int authenticate(BDRVSSHState *s, Error **errp) |
| { |
| int r, ret; |
| int method; |
| |
| /* Try to authenticate with the "none" method. */ |
| r = ssh_userauth_none(s->session, NULL); |
| if (r == SSH_AUTH_ERROR) { |
| ret = -EPERM; |
| session_error_setg(errp, s, "failed to authenticate using none " |
| "authentication"); |
| goto out; |
| } else if (r == SSH_AUTH_SUCCESS) { |
| /* Authenticated! */ |
| ret = 0; |
| goto out; |
| } |
| |
| method = ssh_userauth_list(s->session, NULL); |
| trace_ssh_auth_methods(method); |
| |
| /* |
| * Try to authenticate with publickey, using the ssh-agent |
| * if available. |
| */ |
| if (method & SSH_AUTH_METHOD_PUBLICKEY) { |
| r = ssh_userauth_publickey_auto(s->session, NULL, NULL); |
| if (r == SSH_AUTH_ERROR) { |
| ret = -EINVAL; |
| session_error_setg(errp, s, "failed to authenticate using " |
| "publickey authentication"); |
| goto out; |
| } else if (r == SSH_AUTH_SUCCESS) { |
| /* Authenticated! */ |
| ret = 0; |
| goto out; |
| } |
| } |
| |
| ret = -EPERM; |
| error_setg(errp, "failed to authenticate using publickey authentication " |
| "and the identities held by your ssh-agent"); |
| |
| out: |
| return ret; |
| } |
| |
| static QemuOptsList ssh_runtime_opts = { |
| .name = "ssh", |
| .head = QTAILQ_HEAD_INITIALIZER(ssh_runtime_opts.head), |
| .desc = { |
| { |
| .name = "host", |
| .type = QEMU_OPT_STRING, |
| .help = "Host to connect to", |
| }, |
| { |
| .name = "port", |
| .type = QEMU_OPT_NUMBER, |
| .help = "Port to connect to", |
| }, |
| { |
| .name = "host_key_check", |
| .type = QEMU_OPT_STRING, |
| .help = "Defines how and what to check the host key against", |
| }, |
| { /* end of list */ } |
| }, |
| }; |
| |
| static bool ssh_process_legacy_options(QDict *output_opts, |
| QemuOpts *legacy_opts, |
| Error **errp) |
| { |
| const char *host = qemu_opt_get(legacy_opts, "host"); |
| const char *port = qemu_opt_get(legacy_opts, "port"); |
| const char *host_key_check = qemu_opt_get(legacy_opts, "host_key_check"); |
| |
| if (!host && port) { |
| error_setg(errp, "port may not be used without host"); |
| return false; |
| } |
| |
| if (host) { |
| qdict_put_str(output_opts, "server.host", host); |
| qdict_put_str(output_opts, "server.port", port ?: stringify(22)); |
| } |
| |
| if (host_key_check) { |
| if (strcmp(host_key_check, "no") == 0) { |
| qdict_put_str(output_opts, "host-key-check.mode", "none"); |
| } else if (strncmp(host_key_check, "md5:", 4) == 0) { |
| qdict_put_str(output_opts, "host-key-check.mode", "hash"); |
| qdict_put_str(output_opts, "host-key-check.type", "md5"); |
| qdict_put_str(output_opts, "host-key-check.hash", |
| &host_key_check[4]); |
| } else if (strncmp(host_key_check, "sha1:", 5) == 0) { |
| qdict_put_str(output_opts, "host-key-check.mode", "hash"); |
| qdict_put_str(output_opts, "host-key-check.type", "sha1"); |
| qdict_put_str(output_opts, "host-key-check.hash", |
| &host_key_check[5]); |
| } else if (strcmp(host_key_check, "yes") == 0) { |
| qdict_put_str(output_opts, "host-key-check.mode", "known_hosts"); |
| } else { |
| error_setg(errp, "unknown host_key_check setting (%s)", |
| host_key_check); |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| static BlockdevOptionsSsh *ssh_parse_options(QDict *options, Error **errp) |
| { |
| BlockdevOptionsSsh *result = NULL; |
| QemuOpts *opts = NULL; |
| Error *local_err = NULL; |
| const QDictEntry *e; |
| Visitor *v; |
| |
| /* Translate legacy options */ |
| opts = qemu_opts_create(&ssh_runtime_opts, NULL, 0, &error_abort); |
| qemu_opts_absorb_qdict(opts, options, &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| goto fail; |
| } |
| |
| if (!ssh_process_legacy_options(options, opts, errp)) { |
| goto fail; |
| } |
| |
| /* Create the QAPI object */ |
| v = qobject_input_visitor_new_flat_confused(options, errp); |
| if (!v) { |
| goto fail; |
| } |
| |
| visit_type_BlockdevOptionsSsh(v, NULL, &result, &local_err); |
| visit_free(v); |
| |
| if (local_err) { |
| error_propagate(errp, local_err); |
| goto fail; |
| } |
| |
| /* Remove the processed options from the QDict (the visitor processes |
| * _all_ options in the QDict) */ |
| while ((e = qdict_first(options))) { |
| qdict_del(options, e->key); |
| } |
| |
| fail: |
| qemu_opts_del(opts); |
| return result; |
| } |
| |
| static int connect_to_ssh(BDRVSSHState *s, BlockdevOptionsSsh *opts, |
| int ssh_flags, int creat_mode, Error **errp) |
| { |
| int r, ret; |
| unsigned int port = 0; |
| int new_sock = -1; |
| |
| if (opts->has_user) { |
| s->user = g_strdup(opts->user); |
| } else { |
| s->user = g_strdup(g_get_user_name()); |
| if (!s->user) { |
| error_setg_errno(errp, errno, "Can't get user name"); |
| ret = -errno; |
| goto err; |
| } |
| } |
| |
| /* Pop the config into our state object, Exit if invalid */ |
| s->inet = opts->server; |
| opts->server = NULL; |
| |
| if (qemu_strtoui(s->inet->port, NULL, 10, &port) < 0) { |
| error_setg(errp, "Use only numeric port value"); |
| ret = -EINVAL; |
| goto err; |
| } |
| |
| /* Open the socket and connect. */ |
| new_sock = inet_connect_saddr(s->inet, errp); |
| if (new_sock < 0) { |
| ret = -EIO; |
| goto err; |
| } |
| |
| /* |
| * Try to disable the Nagle algorithm on TCP sockets to reduce latency, |
| * but do not fail if it cannot be disabled. |
| */ |
| r = socket_set_nodelay(new_sock); |
| if (r < 0) { |
| warn_report("can't set TCP_NODELAY for the ssh server %s: %s", |
| s->inet->host, strerror(errno)); |
| } |
| |
| /* Create SSH session. */ |
| s->session = ssh_new(); |
| if (!s->session) { |
| ret = -EINVAL; |
| session_error_setg(errp, s, "failed to initialize libssh session"); |
| goto err; |
| } |
| |
| /* |
| * Make sure we are in blocking mode during the connection and |
| * authentication phases. |
| */ |
| ssh_set_blocking(s->session, 1); |
| |
| r = ssh_options_set(s->session, SSH_OPTIONS_USER, s->user); |
| if (r < 0) { |
| ret = -EINVAL; |
| session_error_setg(errp, s, |
| "failed to set the user in the libssh session"); |
| goto err; |
| } |
| |
| r = ssh_options_set(s->session, SSH_OPTIONS_HOST, s->inet->host); |
| if (r < 0) { |
| ret = -EINVAL; |
| session_error_setg(errp, s, |
| "failed to set the host in the libssh session"); |
| goto err; |
| } |
| |
| if (port > 0) { |
| r = ssh_options_set(s->session, SSH_OPTIONS_PORT, &port); |
| if (r < 0) { |
| ret = -EINVAL; |
| session_error_setg(errp, s, |
| "failed to set the port in the libssh session"); |
| goto err; |
| } |
| } |
| |
| r = ssh_options_set(s->session, SSH_OPTIONS_COMPRESSION, "none"); |
| if (r < 0) { |
| ret = -EINVAL; |
| session_error_setg(errp, s, |
| "failed to disable the compression in the libssh " |
| "session"); |
| goto err; |
| } |
| |
| /* Read ~/.ssh/config. */ |
| r = ssh_options_parse_config(s->session, NULL); |
| if (r < 0) { |
| ret = -EINVAL; |
| session_error_setg(errp, s, "failed to parse ~/.ssh/config"); |
| goto err; |
| } |
| |
| r = ssh_options_set(s->session, SSH_OPTIONS_FD, &new_sock); |
| if (r < 0) { |
| ret = -EINVAL; |
| session_error_setg(errp, s, |
| "failed to set the socket in the libssh session"); |
| goto err; |
| } |
| /* libssh took ownership of the socket. */ |
| s->sock = new_sock; |
| new_sock = -1; |
| |
| /* Connect. */ |
| r = ssh_connect(s->session); |
| if (r != SSH_OK) { |
| 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, opts->host_key_check, errp); |
| if (ret < 0) { |
| goto err; |
| } |
| |
| /* Authenticate. */ |
| ret = authenticate(s, errp); |
| if (ret < 0) { |
| goto err; |
| } |
| |
| /* Start SFTP. */ |
| s->sftp = sftp_new(s->session); |
| if (!s->sftp) { |
| session_error_setg(errp, s, "failed to create sftp handle"); |
| ret = -EINVAL; |
| goto err; |
| } |
| |
| r = sftp_init(s->sftp); |
| if (r < 0) { |
| sftp_error_setg(errp, s, "failed to initialize sftp handle"); |
| ret = -EINVAL; |
| goto err; |
| } |
| |
| /* Open the remote file. */ |
| trace_ssh_connect_to_ssh(opts->path, ssh_flags, creat_mode); |
| s->sftp_handle = sftp_open(s->sftp, opts->path, ssh_flags, creat_mode); |
| if (!s->sftp_handle) { |
| sftp_error_setg(errp, s, "failed to open remote file '%s'", |
| opts->path); |
| ret = -EINVAL; |
| goto err; |
| } |
| |
| /* Make sure the SFTP file is handled in blocking mode. */ |
| sftp_file_set_blocking(s->sftp_handle); |
| |
| s->attrs = sftp_fstat(s->sftp_handle); |
| if (!s->attrs) { |
| sftp_error_setg(errp, s, "failed to read file attributes"); |
| return -EINVAL; |
| } |
| |
| return 0; |
| |
| err: |
| if (s->attrs) { |
| sftp_attributes_free(s->attrs); |
| } |
| s->attrs = NULL; |
| if (s->sftp_handle) { |
| sftp_close(s->sftp_handle); |
| } |
| s->sftp_handle = NULL; |
| if (s->sftp) { |
| sftp_free(s->sftp); |
| } |
| s->sftp = NULL; |
| if (s->session) { |
| ssh_disconnect(s->session); |
| ssh_free(s->session); |
| } |
| s->session = NULL; |
| s->sock = -1; |
| if (new_sock >= 0) { |
| close(new_sock); |
| } |
| |
| return ret; |
| } |
| |
| static int ssh_file_open(BlockDriverState *bs, QDict *options, int bdrv_flags, |
| Error **errp) |
| { |
| BDRVSSHState *s = bs->opaque; |
| BlockdevOptionsSsh *opts; |
| int ret; |
| int ssh_flags; |
| |
| ssh_state_init(s); |
| |
| ssh_flags = 0; |
| if (bdrv_flags & BDRV_O_RDWR) { |
| ssh_flags |= O_RDWR; |
| } else { |
| ssh_flags |= O_RDONLY; |
| } |
| |
| opts = ssh_parse_options(options, errp); |
| if (opts == NULL) { |
| return -EINVAL; |
| } |
| |
| /* Start up SSH. */ |
| ret = connect_to_ssh(s, opts, ssh_flags, 0, errp); |
| if (ret < 0) { |
| goto err; |
| } |
| |
| /* Go non-blocking. */ |
| ssh_set_blocking(s->session, 0); |
| |
| qapi_free_BlockdevOptionsSsh(opts); |
| |
| return 0; |
| |
| err: |
| qapi_free_BlockdevOptionsSsh(opts); |
| |
| return ret; |
| } |
| |
| /* Note: This is a blocking operation */ |
| static int ssh_grow_file(BDRVSSHState *s, int64_t offset, Error **errp) |
| { |
| ssize_t ret; |
| char c[1] = { '\0' }; |
| int was_blocking = ssh_is_blocking(s->session); |
| |
| /* offset must be strictly greater than the current size so we do |
| * not overwrite anything */ |
| assert(offset > 0 && offset > s->attrs->size); |
| |
| ssh_set_blocking(s->session, 1); |
| |
| sftp_seek64(s->sftp_handle, offset - 1); |
| ret = sftp_write(s->sftp_handle, c, 1); |
| |
| ssh_set_blocking(s->session, was_blocking); |
| |
| if (ret < 0) { |
| sftp_error_setg(errp, s, "Failed to grow file"); |
| return -EIO; |
| } |
| |
| s->attrs->size = offset; |
| return 0; |
| } |
| |
| static QemuOptsList ssh_create_opts = { |
| .name = "ssh-create-opts", |
| .head = QTAILQ_HEAD_INITIALIZER(ssh_create_opts.head), |
| .desc = { |
| { |
| .name = BLOCK_OPT_SIZE, |
| .type = QEMU_OPT_SIZE, |
| .help = "Virtual disk size" |
| }, |
| { /* end of list */ } |
| } |
| }; |
| |
| static int ssh_co_create(BlockdevCreateOptions *options, Error **errp) |
| { |
| BlockdevCreateOptionsSsh *opts = &options->u.ssh; |
| BDRVSSHState s; |
| int ret; |
| |
| assert(options->driver == BLOCKDEV_DRIVER_SSH); |
| |
| ssh_state_init(&s); |
| |
| ret = connect_to_ssh(&s, opts->location, |
| O_RDWR | O_CREAT | O_TRUNC, |
| 0644, errp); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| if (opts->size > 0) { |
| ret = ssh_grow_file(&s, opts->size, errp); |
| if (ret < 0) { |
| goto fail; |
| } |
| } |
| |
| ret = 0; |
| fail: |
| ssh_state_free(&s); |
| return ret; |
| } |
| |
| static int coroutine_fn ssh_co_create_opts(const char *filename, QemuOpts *opts, |
| Error **errp) |
| { |
| BlockdevCreateOptions *create_options; |
| BlockdevCreateOptionsSsh *ssh_opts; |
| int ret; |
| QDict *uri_options = NULL; |
| |
| create_options = g_new0(BlockdevCreateOptions, 1); |
| create_options->driver = BLOCKDEV_DRIVER_SSH; |
| ssh_opts = &create_options->u.ssh; |
| |
| /* Get desired file size. */ |
| ssh_opts->size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), |
| BDRV_SECTOR_SIZE); |
| trace_ssh_co_create_opts(ssh_opts->size); |
| |
| uri_options = qdict_new(); |
| ret = parse_uri(filename, uri_options, errp); |
| if (ret < 0) { |
| goto out; |
| } |
| |
| ssh_opts->location = ssh_parse_options(uri_options, errp); |
| if (ssh_opts->location == NULL) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| ret = ssh_co_create(create_options, errp); |
| |
| out: |
| qobject_unref(uri_options); |
| qapi_free_BlockdevCreateOptions(create_options); |
| return ret; |
| } |
| |
| static void ssh_close(BlockDriverState *bs) |
| { |
| BDRVSSHState *s = bs->opaque; |
| |
| ssh_state_free(s); |
| } |
| |
| static int ssh_has_zero_init(BlockDriverState *bs) |
| { |
| BDRVSSHState *s = bs->opaque; |
| /* Assume false, unless we can positively prove it's true. */ |
| int has_zero_init = 0; |
| |
| if (s->attrs->type == SSH_FILEXFER_TYPE_REGULAR) { |
| has_zero_init = 1; |
| } |
| |
| return has_zero_init; |
| } |
| |
| typedef struct BDRVSSHRestart { |
| BlockDriverState *bs; |
| Coroutine *co; |
| } BDRVSSHRestart; |
| |
| static void restart_coroutine(void *opaque) |
| { |
| BDRVSSHRestart *restart = opaque; |
| BlockDriverState *bs = restart->bs; |
| BDRVSSHState *s = bs->opaque; |
| AioContext *ctx = bdrv_get_aio_context(bs); |
| |
| trace_ssh_restart_coroutine(restart->co); |
| aio_set_fd_handler(ctx, s->sock, false, NULL, NULL, NULL, NULL); |
| |
| aio_co_wake(restart->co); |
| } |
| |
| /* A non-blocking call returned EAGAIN, so yield, ensuring the |
| * handlers are set up so that we'll be rescheduled when there is an |
| * interesting event on the socket. |
| */ |
| static coroutine_fn void co_yield(BDRVSSHState *s, BlockDriverState *bs) |
| { |
| int r; |
| IOHandler *rd_handler = NULL, *wr_handler = NULL; |
| BDRVSSHRestart restart = { |
| .bs = bs, |
| .co = qemu_coroutine_self() |
| }; |
| |
| r = ssh_get_poll_flags(s->session); |
| |
| if (r & SSH_READ_PENDING) { |
| rd_handler = restart_coroutine; |
| } |
| if (r & SSH_WRITE_PENDING) { |
| wr_handler = restart_coroutine; |
| } |
| |
| trace_ssh_co_yield(s->sock, rd_handler, wr_handler); |
| |
| aio_set_fd_handler(bdrv_get_aio_context(bs), s->sock, |
| false, rd_handler, wr_handler, NULL, &restart); |
| qemu_coroutine_yield(); |
| trace_ssh_co_yield_back(s->sock); |
| } |
| |
| static coroutine_fn int ssh_read(BDRVSSHState *s, BlockDriverState *bs, |
| int64_t offset, size_t size, |
| QEMUIOVector *qiov) |
| { |
| ssize_t r; |
| size_t got; |
| char *buf, *end_of_vec; |
| struct iovec *i; |
| |
| trace_ssh_read(offset, size); |
| |
| trace_ssh_seek(offset); |
| sftp_seek64(s->sftp_handle, offset); |
| |
| /* This keeps track of the current iovec element ('i'), where we |
| * will write to next ('buf'), and the end of the current iovec |
| * ('end_of_vec'). |
| */ |
| i = &qiov->iov[0]; |
| buf = i->iov_base; |
| end_of_vec = i->iov_base + i->iov_len; |
| |
| for (got = 0; got < size; ) { |
| size_t request_read_size; |
| again: |
| /* |
| * The size of SFTP packets is limited to 32K bytes, so limit |
| * the amount of data requested to 16K, as libssh currently |
| * does not handle multiple requests on its own. |
| */ |
| request_read_size = MIN(end_of_vec - buf, 16384); |
| trace_ssh_read_buf(buf, end_of_vec - buf, request_read_size); |
| r = sftp_read(s->sftp_handle, buf, request_read_size); |
| trace_ssh_read_return(r, sftp_get_error(s->sftp)); |
| |
| if (r == SSH_AGAIN) { |
| co_yield(s, bs); |
| goto again; |
| } |
| if (r == SSH_EOF || (r == 0 && sftp_get_error(s->sftp) == SSH_FX_EOF)) { |
| /* EOF: Short read so pad the buffer with zeroes and return it. */ |
| qemu_iovec_memset(qiov, got, 0, size - got); |
| return 0; |
| } |
| if (r <= 0) { |
| sftp_error_trace(s, "read"); |
| return -EIO; |
| } |
| |
| got += r; |
| buf += r; |
| if (buf >= end_of_vec && got < size) { |
| i++; |
| buf = i->iov_base; |
| end_of_vec = i->iov_base + i->iov_len; |
| } |
| } |
| |
| return 0; |
| } |
| |
| static coroutine_fn int ssh_co_readv(BlockDriverState *bs, |
| int64_t sector_num, |
| int nb_sectors, QEMUIOVector *qiov) |
| { |
| BDRVSSHState *s = bs->opaque; |
| int ret; |
| |
| qemu_co_mutex_lock(&s->lock); |
| ret = ssh_read(s, bs, sector_num * BDRV_SECTOR_SIZE, |
| nb_sectors * BDRV_SECTOR_SIZE, qiov); |
| qemu_co_mutex_unlock(&s->lock); |
| |
| return ret; |
| } |
| |
| static int ssh_write(BDRVSSHState *s, BlockDriverState *bs, |
| int64_t offset, size_t size, |
| QEMUIOVector *qiov) |
| { |
| ssize_t r; |
| size_t written; |
| char *buf, *end_of_vec; |
| struct iovec *i; |
| |
| trace_ssh_write(offset, size); |
| |
| trace_ssh_seek(offset); |
| sftp_seek64(s->sftp_handle, offset); |
| |
| /* This keeps track of the current iovec element ('i'), where we |
| * will read from next ('buf'), and the end of the current iovec |
| * ('end_of_vec'). |
| */ |
| i = &qiov->iov[0]; |
| buf = i->iov_base; |
| end_of_vec = i->iov_base + i->iov_len; |
| |
| for (written = 0; written < size; ) { |
| size_t request_write_size; |
| again: |
| /* |
| * Avoid too large data packets, as libssh currently does not |
| * handle multiple requests on its own. |
| */ |
| request_write_size = MIN(end_of_vec - buf, 131072); |
| trace_ssh_write_buf(buf, end_of_vec - buf, request_write_size); |
| r = sftp_write(s->sftp_handle, buf, request_write_size); |
| trace_ssh_write_return(r, sftp_get_error(s->sftp)); |
| |
| if (r == SSH_AGAIN) { |
| co_yield(s, bs); |
| goto again; |
| } |
| if (r < 0) { |
| sftp_error_trace(s, "write"); |
| return -EIO; |
| } |
| |
| written += r; |
| buf += r; |
| if (buf >= end_of_vec && written < size) { |
| i++; |
| buf = i->iov_base; |
| end_of_vec = i->iov_base + i->iov_len; |
| } |
| |
| if (offset + written > s->attrs->size) { |
| s->attrs->size = offset + written; |
| } |
| } |
| |
| return 0; |
| } |
| |
| static coroutine_fn int ssh_co_writev(BlockDriverState *bs, |
| int64_t sector_num, |
| int nb_sectors, QEMUIOVector *qiov, |
| int flags) |
| { |
| BDRVSSHState *s = bs->opaque; |
| int ret; |
| |
| assert(!flags); |
| qemu_co_mutex_lock(&s->lock); |
| ret = ssh_write(s, bs, sector_num * BDRV_SECTOR_SIZE, |
| nb_sectors * BDRV_SECTOR_SIZE, qiov); |
| qemu_co_mutex_unlock(&s->lock); |
| |
| return ret; |
| } |
| |
| static void unsafe_flush_warning(BDRVSSHState *s, const char *what) |
| { |
| if (!s->unsafe_flush_warning) { |
| warn_report("ssh server %s does not support fsync", |
| s->inet->host); |
| if (what) { |
| error_report("to support fsync, you need %s", what); |
| } |
| s->unsafe_flush_warning = true; |
| } |
| } |
| |
| #ifdef HAVE_LIBSSH_0_8 |
| |
| static coroutine_fn int ssh_flush(BDRVSSHState *s, BlockDriverState *bs) |
| { |
| int r; |
| |
| trace_ssh_flush(); |
| |
| if (!sftp_extension_supported(s->sftp, "fsync@openssh.com", "1")) { |
| unsafe_flush_warning(s, "OpenSSH >= 6.3"); |
| return 0; |
| } |
| again: |
| r = sftp_fsync(s->sftp_handle); |
| if (r == SSH_AGAIN) { |
| co_yield(s, bs); |
| goto again; |
| } |
| if (r < 0) { |
| sftp_error_trace(s, "fsync"); |
| return -EIO; |
| } |
| |
| return 0; |
| } |
| |
| static coroutine_fn int ssh_co_flush(BlockDriverState *bs) |
| { |
| BDRVSSHState *s = bs->opaque; |
| int ret; |
| |
| qemu_co_mutex_lock(&s->lock); |
| ret = ssh_flush(s, bs); |
| qemu_co_mutex_unlock(&s->lock); |
| |
| return ret; |
| } |
| |
| #else /* !HAVE_LIBSSH_0_8 */ |
| |
| static coroutine_fn int ssh_co_flush(BlockDriverState *bs) |
| { |
| BDRVSSHState *s = bs->opaque; |
| |
| unsafe_flush_warning(s, "libssh >= 0.8.0"); |
| return 0; |
| } |
| |
| #endif /* !HAVE_LIBSSH_0_8 */ |
| |
| static int64_t ssh_getlength(BlockDriverState *bs) |
| { |
| BDRVSSHState *s = bs->opaque; |
| int64_t length; |
| |
| /* Note we cannot make a libssh call here. */ |
| length = (int64_t) s->attrs->size; |
| trace_ssh_getlength(length); |
| |
| return length; |
| } |
| |
| static int coroutine_fn ssh_co_truncate(BlockDriverState *bs, int64_t offset, |
| PreallocMode prealloc, Error **errp) |
| { |
| BDRVSSHState *s = bs->opaque; |
| |
| if (prealloc != PREALLOC_MODE_OFF) { |
| error_setg(errp, "Unsupported preallocation mode '%s'", |
| PreallocMode_str(prealloc)); |
| return -ENOTSUP; |
| } |
| |
| if (offset < s->attrs->size) { |
| error_setg(errp, "ssh driver does not support shrinking files"); |
| return -ENOTSUP; |
| } |
| |
| if (offset == s->attrs->size) { |
| return 0; |
| } |
| |
| return ssh_grow_file(s, offset, errp); |
| } |
| |
| static void ssh_refresh_filename(BlockDriverState *bs) |
| { |
| BDRVSSHState *s = bs->opaque; |
| const char *path, *host_key_check; |
| int ret; |
| |
| /* |
| * None of these options can be represented in a plain "host:port" |
| * format, so if any was given, we have to abort. |
| */ |
| if (s->inet->has_ipv4 || s->inet->has_ipv6 || s->inet->has_to || |
| s->inet->has_numeric) |
| { |
| return; |
| } |
| |
| path = qdict_get_try_str(bs->full_open_options, "path"); |
| assert(path); /* mandatory option */ |
| |
| host_key_check = qdict_get_try_str(bs->full_open_options, "host_key_check"); |
| |
| ret = snprintf(bs->exact_filename, sizeof(bs->exact_filename), |
| "ssh://%s@%s:%s%s%s%s", |
| s->user, s->inet->host, s->inet->port, path, |
| host_key_check ? "?host_key_check=" : "", |
| host_key_check ?: ""); |
| if (ret >= sizeof(bs->exact_filename)) { |
| /* An overflow makes the filename unusable, so do not report any */ |
| bs->exact_filename[0] = '\0'; |
| } |
| } |
| |
| static char *ssh_bdrv_dirname(BlockDriverState *bs, Error **errp) |
| { |
| if (qdict_haskey(bs->full_open_options, "host_key_check")) { |
| /* |
| * We cannot generate a simple prefix if we would have to |
| * append a query string. |
| */ |
| error_setg(errp, |
| "Cannot generate a base directory with host_key_check set"); |
| return NULL; |
| } |
| |
| if (bs->exact_filename[0] == '\0') { |
| error_setg(errp, "Cannot generate a base directory for this ssh node"); |
| return NULL; |
| } |
| |
| return path_combine(bs->exact_filename, ""); |
| } |
| |
| static const char *const ssh_strong_runtime_opts[] = { |
| "host", |
| "port", |
| "path", |
| "user", |
| "host_key_check", |
| "server.", |
| |
| NULL |
| }; |
| |
| static BlockDriver bdrv_ssh = { |
| .format_name = "ssh", |
| .protocol_name = "ssh", |
| .instance_size = sizeof(BDRVSSHState), |
| .bdrv_parse_filename = ssh_parse_filename, |
| .bdrv_file_open = ssh_file_open, |
| .bdrv_co_create = ssh_co_create, |
| .bdrv_co_create_opts = ssh_co_create_opts, |
| .bdrv_close = ssh_close, |
| .bdrv_has_zero_init = ssh_has_zero_init, |
| .bdrv_co_readv = ssh_co_readv, |
| .bdrv_co_writev = ssh_co_writev, |
| .bdrv_getlength = ssh_getlength, |
| .bdrv_co_truncate = ssh_co_truncate, |
| .bdrv_co_flush_to_disk = ssh_co_flush, |
| .bdrv_refresh_filename = ssh_refresh_filename, |
| .bdrv_dirname = ssh_bdrv_dirname, |
| .create_opts = &ssh_create_opts, |
| .strong_runtime_opts = ssh_strong_runtime_opts, |
| }; |
| |
| static void bdrv_ssh_init(void) |
| { |
| int r; |
| |
| r = ssh_init(); |
| if (r != 0) { |
| fprintf(stderr, "libssh initialization failed, %d\n", r); |
| exit(EXIT_FAILURE); |
| } |
| |
| #if TRACE_LIBSSH != 0 |
| ssh_set_log_level(TRACE_LIBSSH); |
| #endif |
| |
| bdrv_register(&bdrv_ssh); |
| } |
| |
| block_init(bdrv_ssh_init); |