From patchwork Tue Mar 26 10:38:46 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Richard W.M. Jones" X-Patchwork-Id: 231162 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 899F12C008D for ; Tue, 26 Mar 2013 21:39:36 +1100 (EST) Received: from localhost ([::1]:50394 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UKRHy-0000mJ-PW for incoming@patchwork.ozlabs.org; Tue, 26 Mar 2013 06:39:34 -0400 Received: from eggs.gnu.org ([208.118.235.92]:35226) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UKRHR-0000aR-5d for qemu-devel@nongnu.org; Tue, 26 Mar 2013 06:39:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UKRHM-0002VO-LP for qemu-devel@nongnu.org; Tue, 26 Mar 2013 06:39:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:25484) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UKRHM-0002VK-80 for qemu-devel@nongnu.org; Tue, 26 Mar 2013 06:38:56 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r2QActlr021729 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 26 Mar 2013 06:38:55 -0400 Received: from choo.home.annexia.org (vpn1-6-22.ams2.redhat.com [10.36.6.22]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id r2QAcqSW028902 for ; Tue, 26 Mar 2013 06:38:53 -0400 From: "Richard W.M. Jones" To: qemu-devel@nongnu.org Date: Tue, 26 Mar 2013 10:38:46 +0000 Message-Id: <1364294326-22155-1-git-send-email-rjones@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.12 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v3] block: Add support for Secure Shell (ssh) block device. X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: "Richard W.M. Jones" qemu-system-x86_64 -drive file=ssh://hostname/some/image QEMU will ssh into 'hostname' and open '/some/image' which is made available as a standard block device. You can specify a username (ssh://user@host/...) and/or a port number (ssh://host:port/...). Current limitations: - Authentication must be done without passwords or passphrases, using ssh-agent. Other authentication methods are not supported. (*) - New remote files cannot be created. (*) - Uses a single connection, instead of concurrent AIO with multiple SSH connections. (*) = potentially easy fix This is implemented using libssh2 on the client side. The server just requires a regular ssh daemon with sftp-server support. Most ssh daemons on Unix/Linux systems will work out of the box. Thanks: Stefan Hajnoczi, Kevin Wolf. --- block/Makefile.objs | 1 + block/ssh.c | 750 ++++++++++++++++++++++++++++++++++++++++++++++++++++ configure | 47 ++++ qemu-doc.texi | 40 +++ qemu-options.hx | 12 + 5 files changed, 850 insertions(+) create mode 100644 block/ssh.c diff --git a/block/Makefile.objs b/block/Makefile.objs index c067f38..6c4b5bc 100644 --- a/block/Makefile.objs +++ b/block/Makefile.objs @@ -13,6 +13,7 @@ block-obj-$(CONFIG_LIBISCSI) += iscsi.o block-obj-$(CONFIG_CURL) += curl.o block-obj-$(CONFIG_RBD) += rbd.o block-obj-$(CONFIG_GLUSTERFS) += gluster.o +block-obj-$(CONFIG_LIBSSH2) += ssh.o endif common-obj-y += stream.o diff --git a/block/ssh.c b/block/ssh.c new file mode 100644 index 0000000..f7b8d32 --- /dev/null +++ b/block/ssh.c @@ -0,0 +1,750 @@ +/* + * Secure Shell (ssh) backend for QEMU. + * + * Copyright (C) 2013 Red Hat Inc., Richard W.M. Jones + * + * 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 +#include +#include + +#ifndef _WIN32 +#include +#endif + +#include +#include + +#include "block/block_int.h" +#include "qemu/sockets.h" +#include "qemu/uri.h" +#include "qapi/qmp/qint.h" + +#define DEBUG_SSH 1 + +#if DEBUG_SSH +#define DPRINTF(fmt,...) \ + do { \ + fprintf(stderr, "ssh: %-15s " fmt "\n", __func__, ##__VA_ARGS__); \ + } while (0) +#else +#define DPRINTF(fmt,...) /* nothing */ +#endif + +typedef struct BDRVSSHState { + CoMutex lock; /* coroutine lock */ + + /* ssh connection */ + int sock; /* socket */ + LIBSSH2_SESSION *session; /* ssh session */ + LIBSSH2_SFTP *sftp; /* sftp session */ + LIBSSH2_SFTP_HANDLE *sftp_handle; /* sftp remote file handle */ + + /* file attributes (at open) */ + LIBSSH2_SFTP_ATTRIBUTES attrs; +} BDRVSSHState; + +/* Wrappers around error_report which make sure to dump as much + * information from libssh2 as possible. + */ +static void +session_error_report(BDRVSSHState *s, const char *fs, ...) +{ + va_list args; + + va_start(args, fs); + + if ((s)->session) { + char *ssh_err; + int ssh_err_len = sizeof ssh_err; + int ssh_err_code; + + libssh2_session_last_error((s)->session, + &ssh_err, &ssh_err_len, 0); + /* This is not an errno. See . */ + ssh_err_code = libssh2_session_last_errno((s)->session); + + error_vprintf(fs, args); + error_printf(": %s (libssh2 error code: %d)", ssh_err, ssh_err_code); + } + else { + error_vprintf(fs, args); + } + + va_end(args); + error_printf("\n"); +} + +static void +sftp_error_report(BDRVSSHState *s, const char *fs, ...) +{ + va_list args; + + va_start(args, fs); + + if ((s)->sftp) { + char *ssh_err; + int ssh_err_len = sizeof ssh_err; + int ssh_err_code; + unsigned long sftp_err_code; + + libssh2_session_last_error((s)->session, + &ssh_err, &ssh_err_len, 0); + /* This is not an errno. See . */ + ssh_err_code = libssh2_session_last_errno((s)->session); + /* See . */ + sftp_err_code = libssh2_sftp_last_error((s)->sftp); + + error_vprintf(fs, args); + error_printf(": %s (libssh2 error code: %d, sftp error code: %lu)", + ssh_err, ssh_err_code, sftp_err_code); + } + else { + error_vprintf(fs, args); + } + + va_end(args); + error_printf("\n"); +} + +#ifndef _WIN32 +static const char *get_username(void) +{ + struct passwd *pwd; + + pwd = getpwuid(geteuid ()); + if (!pwd) { + error_report("failed to get current user name"); + return NULL; + } + return pwd->pw_name; +} +#else +static const char *get_username(void) +{ + error_report("on Windows, specify a remote user name in the URI"); + return NULL; +} +#endif + +static int parse_uri(const char *filename, QDict *options) +{ + URI *uri; + char *host = NULL; + + uri = uri_parse(filename); + if (!uri) { + return -EINVAL; + } + + if (strcmp(uri->scheme, "ssh") != 0) { + error_report("URI scheme must be 'ssh'"); + goto err; + } + + if (!uri->server || strcmp(uri->server, "") == 0) { + error_report("missing hostname in URI"); + goto err; + } + + if (!uri->path || strcmp(uri->path, "") == 0) { + error_report("missing remote path in URI"); + goto err; + } + + if(uri->user && strcmp(uri->user, "") != 0) { + qdict_put(options, "user", qstring_from_str(uri->user)); + } + + qdict_put(options, "host", qstring_from_str(uri->server)); + + if (uri->port) { + qdict_put(options, "port", qint_from_int(uri->port)); + } + + qdict_put(options, "path", qstring_from_str(uri->path)); + + uri_free(uri); + free(host); + return 0; + + err: + uri_free(uri); + free(host); + return -EINVAL; +} + +static void ssh_parse_filename(const char *filename, QDict *options, + Error **errp) +{ + if (qdict_haskey(options, "user") || + qdict_haskey(options, "host") || + qdict_haskey(options, "port") || + qdict_haskey(options, "path")) { + error_setg(errp, "user, host, port or path cannot be used at the same time as a file option"); + return; + } + + if (parse_uri(filename, options) < 0) { + error_setg(errp, "no valid URL specified"); + } +} + +static int check_host_key(BDRVSSHState *s, const char *host, int port) +{ + int ret; + const char *home; + char *knh_file = NULL; + LIBSSH2_KNOWNHOSTS *knh = NULL; + const char *fingerprint; + size_t len; + int type; + + knh = libssh2_knownhost_init(s->session); + if (!knh) { + ret = -EINVAL; + session_error_report(s, "failed to initialize known hosts support"); + goto out; + } + + home = getenv("HOME"); + if (home) { + knh_file = g_strdup_printf("%s/.ssh/known_hosts", home); + } else { + knh_file = g_strdup_printf("/root/.ssh/known_hosts"); + } + + /* Read all known hosts from OpenSSH-style known_hosts file. */ + libssh2_knownhost_readfile(knh, knh_file, LIBSSH2_KNOWNHOST_FILE_OPENSSH); + + fingerprint = libssh2_session_hostkey(s->session, &len, &type); + if (fingerprint) { + struct libssh2_knownhost *found; + int r; + + r = libssh2_knownhost_checkp(knh, host, port, fingerprint, len, + LIBSSH2_KNOWNHOST_TYPE_PLAIN| + LIBSSH2_KNOWNHOST_KEYENC_RAW, + &found); + switch (r) { + case LIBSSH2_KNOWNHOST_CHECK_MATCH: + /* OK */ + DPRINTF("host key OK: %s", found->key); + break; + case LIBSSH2_KNOWNHOST_CHECK_MISMATCH: + ret = -EINVAL; + session_error_report(s, "host key does not match the one in known_hosts (found key %s)", + found->key); + goto out; + case LIBSSH2_KNOWNHOST_CHECK_NOTFOUND: + ret = -EINVAL; + session_error_report(s, "no host key was found in known_hosts"); + goto out; + case LIBSSH2_KNOWNHOST_CHECK_FAILURE: + ret = -EINVAL; + session_error_report(s, "failure matching the host key with known_hosts"); + goto out; + default: + ret = -EINVAL; + session_error_report(s, "unknown error matching the host key with known_hosts (%d)", + r); + goto out; + } + } + + ret = 0; + + out: + if (knh != NULL) { + libssh2_knownhost_free(knh); + } + g_free(knh_file); + return ret; +} + +static int authenticate(BDRVSSHState *s, const char *user) +{ + int r, ret; + const char *userauthlist; + LIBSSH2_AGENT *agent = NULL; + struct libssh2_agent_publickey *identity; + struct libssh2_agent_publickey *prev_identity = NULL; + + userauthlist = libssh2_userauth_list(s->session, user, strlen(user)); + if (strstr(userauthlist, "publickey") == NULL) { + ret = -EPERM; + error_report("remote server does not support \"publickey\" authentication"); + goto out; + } + + /* Connect to ssh-agent and try each identity in turn. */ + agent = libssh2_agent_init(s->session); + if (!agent) { + ret = -EINVAL; + session_error_report(s, "failed to initialize ssh-agent support"); + goto out; + } + if (libssh2_agent_connect(agent)) { + ret = -ECONNREFUSED; + session_error_report(s, "failed to connect to ssh-agent"); + goto out; + } + if (libssh2_agent_list_identities(agent)) { + ret = -EINVAL; + session_error_report(s, "failed requesting identities from ssh-agent"); + goto out; + } + + for(;;) { + r = libssh2_agent_get_identity(agent, &identity, prev_identity); + if (r == 1) { /* end of list */ + break; + } + if (r < 0) { + ret = -EINVAL; + session_error_report(s, "failed to obtain identity from ssh-agent"); + goto out; + } + r = libssh2_agent_userauth(agent, user, identity); + if (r == 0) { + /* Authenticated! */ + ret = 0; + goto out; + } + /* Failed to authenticate with this identity, try the next one. */ + prev_identity = identity; + } + + ret = -EPERM; + error_report("failed to authenticate using publickey authentication " + "and the identities held by your ssh-agent"); + + out: + if (agent != NULL) { + /* Note: libssh2 implementation implicitly calls + * libssh2_agent_disconnect if necessary. + */ + libssh2_agent_free(agent); + } + + return ret; +} + +static int connect_to_ssh(BDRVSSHState *s, QDict *options, int bdrv_flags) +{ + int r, ret, flags; + Error *err = NULL; + const char *host, *user, *path; + int port; + char *hostport = NULL; + + host = qdict_get_str(options, "host"); + + if (qdict_haskey(options, "port")) { + port = qdict_get_int(options, "port"); + } else { + port = 22; + } + + path = qdict_get_str(options, "path"); + + if (qdict_haskey(options, "user")) { + user = qdict_get_str(options, "user"); + } else { + user = get_username(); + if (!user) { + ret = -EINVAL; + goto err; + } + } + + /* Open the socket and connect. */ + hostport = g_strdup_printf("%s:%d", host, port); + s->sock = inet_connect(hostport, &err); + if (err != NULL) { + ret = -errno; + qerror_report_err(err); + error_free(err); + goto err; + } + + /* Create SSH session. */ + s->session = libssh2_session_init(); + if (!s->session) { + ret = -EINVAL; + session_error_report(s, "failed to initialize libssh2 session"); + goto err; + } + + r = libssh2_session_handshake(s->session, s->sock); + if (r != 0) { + ret = -EINVAL; + session_error_report(s, "failed to establish SSH session"); + goto err; + } + + /* Check the remote host's key against known_hosts. */ + ret = check_host_key(s, host, port); + if (ret < 0) { + goto err; + } + + /* Authenticate. */ + ret = authenticate(s, user); + if (ret < 0) { + goto err; + } + + /* Start SFTP. */ + s->sftp = libssh2_sftp_init(s->session); + if (!s->sftp) { + session_error_report(s, "failed to initialize sftp handle"); + ret = -EINVAL; + goto err; + } + + /* Open the remote file. */ + flags = LIBSSH2_FXF_READ; + if (bdrv_flags & BDRV_O_RDWR) { + flags |= LIBSSH2_FXF_WRITE; + } + s->sftp_handle = libssh2_sftp_open(s->sftp, path, flags, 0); + if (!s->sftp_handle) { + session_error_report(s, "failed to open remote file '%s'", path); + ret = -EINVAL; + goto err; + } + + r = libssh2_sftp_fstat(s->sftp_handle, &s->attrs); + if (r < 0) { + sftp_error_report(s, "failed to read file attributes of '%s'", + path); + ret = -EINVAL; + goto err; + } + + /* Delete the options we've used; any not deleted will cause the + * block layer to give an error about unused options. + */ + qdict_del(options, "host"); + qdict_del(options, "port"); + qdict_del(options, "user"); + qdict_del(options, "path"); + + g_free(hostport); + return 0; + + err: + if (s->sftp_handle) { + libssh2_sftp_close(s->sftp_handle); + } + s->sftp_handle = NULL; + if (s->sftp) { + libssh2_sftp_shutdown(s->sftp); + } + s->sftp = NULL; + if (s->session) { + libssh2_session_disconnect(s->session, + "from qemu ssh client: " + "error opening connection"); + libssh2_session_free(s->session); + } + s->session = NULL; + g_free(hostport); + + return ret; +} + +static int ssh_file_open(BlockDriverState *bs, const char *filename, + QDict *options, int bdrv_flags) +{ + BDRVSSHState *s = bs->opaque; + int ret; + + s->sock = -1; + qemu_co_mutex_init(&s->lock); + + /* Start up SSH. */ + ret = connect_to_ssh(s, options, bdrv_flags); + if (ret < 0) { + goto err; + } + + /* Go non-blocking. */ + libssh2_session_set_blocking(s->session, 0); + + return 0; + + err: + if (s->sock >= 0) { + close(s->sock); + } + s->sock = -1; + + return ret; +} + +static void ssh_close(BlockDriverState *bs) +{ + BDRVSSHState *s = bs->opaque; + + if (s->sftp_handle) { + libssh2_sftp_close(s->sftp_handle); + } + if (s->sftp) { + libssh2_sftp_shutdown(s->sftp); + } + if (s->session) { + libssh2_session_disconnect(s->session, + "from qemu ssh client: " + "user closed the connection"); + libssh2_session_free(s->session); + } + if (s->sock >= 0) { + close(s->sock); + } +} + +static void restart_coroutine(void *opaque) +{ + Coroutine *co = opaque; + + qemu_coroutine_enter(co, NULL); +} + +/* Always true because when we have called set_fd_handler there is + * always a request being processed. + */ +static int return_true(void *opaque) +{ + return 1; +} + +static coroutine_fn void set_fd_handler(BDRVSSHState *s) +{ + int r; + IOHandler *rd_handler = NULL, *wr_handler = NULL; + Coroutine *co = qemu_coroutine_self(); + + r = libssh2_session_block_directions(s->session); + + if (r & LIBSSH2_SESSION_BLOCK_INBOUND) { + rd_handler = restart_coroutine; + } + if (r & LIBSSH2_SESSION_BLOCK_OUTBOUND) { + wr_handler = restart_coroutine; + } + + DPRINTF("s->sock=%d rd_handler=%p wr_handler=%p", s->sock, + rd_handler, wr_handler); + + qemu_aio_set_fd_handler(s->sock, rd_handler, wr_handler, return_true, co); +} + +static coroutine_fn void clear_fd_handler(BDRVSSHState *s) +{ + qemu_aio_set_fd_handler(s->sock, NULL, NULL, NULL, NULL); +} + +/* 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) +{ + set_fd_handler(s); + qemu_coroutine_yield(); + clear_fd_handler(s); +} + +static coroutine_fn int ssh_read(BDRVSSHState *s, + int64_t offset, size_t size, + QEMUIOVector *qiov) +{ + ssize_t r; + size_t got; + char *buf, *end_of_vec; + struct iovec *i; + + DPRINTF("offset=%" PRIi64 " size=%zu", offset, size); + + /* According to the docs, this just updates a field in the + * sftp_handle structure, so there is no network traffic and it + * cannot fail. + */ + libssh2_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; + + /* libssh2 has a hard-coded limit of 2000 bytes per request, + * although it will also do readahead behind our backs. Therefore + * we may have to do repeated reads here until we have read 'size' + * bytes. + */ + for (got = 0; got < size; ) { + again: + DPRINTF("sftp_read buf=%p size=%zu", buf, end_of_vec - buf); + r = libssh2_sftp_read(s->sftp_handle, buf, end_of_vec - buf); + + if (r == LIBSSH2_ERROR_EAGAIN || r == LIBSSH2_ERROR_TIMEOUT) { + co_yield(s); + goto again; + } + if (r < 0) { + sftp_error_report(s, "read failed"); + return -EIO; + } + if (r == 0) { + error_report("read failed (EOF)"); + return -EIO; + } + + got += r; + buf += r; + if (buf >= end_of_vec) { + 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, 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, + int64_t offset, size_t size, + QEMUIOVector *qiov) +{ + ssize_t r; + size_t written; + char *buf, *end_of_vec; + struct iovec *i; + + DPRINTF("offset=%" PRIi64 " size=%zu", offset, size); + + /* According to the docs, this just updates a field in the + * sftp_handle structure, so there is no network traffic and it + * cannot fail. + */ + libssh2_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; ) { + again: + DPRINTF("sftp_write buf=%p size=%zu", buf, end_of_vec - buf); + r = libssh2_sftp_write(s->sftp_handle, buf, end_of_vec - buf); + + if (r == LIBSSH2_ERROR_EAGAIN || r == LIBSSH2_ERROR_TIMEOUT) { + co_yield(s); + goto again; + } + if (r < 0) { + sftp_error_report(s, "write failed"); + return -EIO; + } + + written += r; + buf += r; + if (buf >= end_of_vec) { + i++; + buf = i->iov_base; + end_of_vec = i->iov_base + i->iov_len; + } + } + + return 0; +} + +static coroutine_fn int ssh_co_writev(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_write(s, sector_num * BDRV_SECTOR_SIZE, + nb_sectors * BDRV_SECTOR_SIZE, qiov); + qemu_co_mutex_unlock(&s->lock); + + return ret; +} + +static int64_t ssh_getlength(BlockDriverState *bs) +{ + BDRVSSHState *s = bs->opaque; + return (int64_t) s->attrs.filesize; +} + +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_close = ssh_close, + .bdrv_co_readv = ssh_co_readv, + .bdrv_co_writev = ssh_co_writev, + .bdrv_getlength = ssh_getlength, +}; + +static void bdrv_ssh_init(void) +{ + int r; + + r = libssh2_init(0); + if (r != 0) { + fprintf(stderr, "libssh2 initialization failed, %d\n", r); + exit(EXIT_FAILURE); + } + + bdrv_register(&bdrv_ssh); +} + +block_init(bdrv_ssh_init); diff --git a/configure b/configure index f2af714..d666066 100755 --- a/configure +++ b/configure @@ -229,6 +229,7 @@ virtio_blk_data_plane="" gtk="" gtkabi="2.0" tpm="no" +libssh2="" # parse CC options first for opt do @@ -908,6 +909,10 @@ for opt do ;; --enable-tpm) tpm="yes" ;; + --disable-libssh2) libssh2="no" + ;; + --enable-libssh2) libssh2="yes" + ;; *) echo "ERROR: unknown option $opt"; show_help="yes" ;; esac @@ -1166,6 +1171,7 @@ echo " --disable-glusterfs disable GlusterFS backend" echo " --enable-gcov enable test coverage analysis with gcov" echo " --gcov=GCOV use specified gcov [$gcov_tool]" echo " --enable-tpm enable TPM support" +echo " --enable-libssh2 enable ssh block device support" echo "" echo "NOTE: The object files are built at the place where configure is launched" exit 1 @@ -2330,6 +2336,42 @@ EOF fi ########################################## +# libssh2 probe +if test "$libssh2" != "no" ; then + cat > $TMPC < +#include +#include +int main(void) { + LIBSSH2_SESSION *session; + session = libssh2_session_init (); + (void) libssh2_sftp_init (session); + return 0; +} +EOF + + if $pkg_config libssh2 --modversion >/dev/null 2>&1; then + libssh2_cflags=`$pkg_config libssh2 --cflags` + libssh2_libs=`$pkg_config libssh2 --libs` + else + libssh2_cflags= + libssh2_libs="-lssh2" + fi + + if compile_prog "$libssh2_cflags" "$libssh2_libs" ; then + libssh2=yes + libs_tools="$libssh2_libs $libs_tools" + libs_softmmu="$libssh2_libs $libs_softmmu" + QEMU_CFLAGS="$QEMU_CFLAGS $libssh2_cflags" + else + if test "$libssh2" = "yes" ; then + feature_not_found "libssh2" + fi + libssh2=no + fi +fi + +########################################## # linux-aio probe if test "$linux_aio" != "no" ; then @@ -3441,6 +3483,7 @@ echo "virtio-blk-data-plane $virtio_blk_data_plane" echo "gcov $gcov_tool" echo "gcov enabled $gcov" echo "TPM support $tpm" +echo "libssh2 support $libssh2" if test "$sdl_too_old" = "yes"; then echo "-> Your SDL version is too old - please upgrade to have SDL support" @@ -3806,6 +3849,10 @@ if test "$glusterfs" = "yes" ; then echo "CONFIG_GLUSTERFS=y" >> $config_host_mak fi +if test "$libssh2" = "yes" ; then + echo "CONFIG_LIBSSH2=y" >> $config_host_mak +fi + if test "$virtio_blk_data_plane" = "yes" ; then echo "CONFIG_VIRTIO_BLK_DATA_PLANE=y" >> $config_host_mak fi diff --git a/qemu-doc.texi b/qemu-doc.texi index af84bef..7a0f373 100644 --- a/qemu-doc.texi +++ b/qemu-doc.texi @@ -423,6 +423,7 @@ snapshots. * disk_images_sheepdog:: Sheepdog disk images * disk_images_iscsi:: iSCSI LUNs * disk_images_gluster:: GlusterFS disk images +* disk_images_ssh:: Secure Shell (ssh) disk images @end menu @node disk_images_quickstart @@ -1038,6 +1039,45 @@ qemu-system-x86_64 -drive file=gluster+unix:///testvol/dir/a.img?socket=/tmp/glu qemu-system-x86_64 -drive file=gluster+rdma://1.2.3.4:24007/testvol/a.img @end example +@node disk_images_ssh +@subsection Secure Shell (ssh) disk images + +You can access disk images located on a remote ssh server +by using the ssh protocol: + +@example +qemu-system-x86_64 -drive file=ssh://[@var{user}@@]@var{server}[:@var{port}]/@var{path} +@end example + +Alternative syntax using properties: + +@example +qemu-system-x86_64 -drive file.driver=ssh[,file.user=@var{user}],file.host=@var{server}[,file.port=@var{port}],file.path=@var{path} +@end example + +@var{ssh} is the protocol. + +@var{user} is the remote user. If not specified, then the local +username is tried. + +@var{server} specifies the remote ssh server. Any ssh server can be +used, but it must implement the sftp-server protocol. Most Unix/Linux +systems should work without requiring any extra configuration. + +@var{port} is the port number on which sshd is listening. By default +the standard ssh port (22) is used. + +@var{path} is the path to the disk image. + +Currently authentication must be done using ssh-agent. Other +authentication methods may be supported in future. + +Note: The ssh driver does not obey disk flush requests (ie. to commit +data to the backing disk when the guest requests it). This is because +the underlying protocol (SFTP) does not support this. Thus there is a +risk of guest disk corruption if the remote server or network goes +down during writes. + @node pcsys_network @section Network emulation diff --git a/qemu-options.hx b/qemu-options.hx index d7afeab..590a287 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -2106,6 +2106,18 @@ Example for Unix Domain Sockets qemu-system-i386 --drive file=nbd:unix:/tmp/nbd-socket @end example +@item SSH +QEMU supports SSH (Secure Shell) access to remote disks. + +Examples: +@example +qemu-system-i386 -drive file=ssh://user@@host/path/to/disk.img +qemu-system-i386 -drive file.driver=ssh,file.user=user,file.host=host,file.port=22,file.path=/path/to/disk.img +@end example + +Currently authentication must be done using ssh-agent. Other +authentication methods may be supported in future. + @item Sheepdog Sheepdog is a distributed storage system for QEMU. QEMU supports using either local sheepdog devices or remote networked