/* * 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; const QDictEntry *e; Visitor *v; /* Translate legacy options */ opts = qemu_opts_create(&ssh_runtime_opts, NULL, 0, &error_abort); if (!qemu_opts_absorb_qdict(opts, options, errp)) { 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, errp); visit_free(v); if (!result) { 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); if (s->attrs->type == SSH_FILEXFER_TYPE_REGULAR) { bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE; } 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(BlockDriver *drv, 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, bool exact, PreallocMode prealloc, BdrvRequestFlags flags, 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);