/* nbd_request_simple_option: Send an option request, and parse the reply * return 1 for successful negotiation, * 0 if operation is unsupported, * -1 with errp set for any other error */ static int nbd_request_simple_option(QIOChannel *ioc, int opt, Error **errp) { NBDOptionReply reply; int error; if (nbd_send_option_request(ioc, opt, 0, NULL, errp) < 0) { return -1; } if (nbd_receive_option_reply(ioc, opt, &reply, errp) < 0) { return -1; } error = nbd_handle_reply_err(ioc, &reply, errp); if (error <= 0) { return error; } if (reply.type != NBD_REP_ACK) { error_setg(errp, "Server answered option %d (%s) with unexpected " "reply %" PRIu32 " (%s)", opt, nbd_opt_lookup(opt), reply.type, nbd_rep_lookup(reply.type)); nbd_send_opt_abort(ioc); return -1; } if (reply.length != 0) { error_setg(errp, "Option %d ('%s') response length is %" PRIu32 " (it should be zero)", opt, nbd_opt_lookup(opt), reply.length); nbd_send_opt_abort(ioc); return -1; } return 1; }
static QIOChannel *nbd_receive_starttls(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, const char *hostname, Error **errp) { nbd_opt_reply reply; QIOChannelTLS *tioc; struct NBDTLSHandshakeData data = { 0 }; trace_nbd_receive_starttls_request(); if (nbd_send_option_request(ioc, NBD_OPT_STARTTLS, 0, NULL, errp) < 0) { return NULL; } trace_nbd_receive_starttls_reply(); if (nbd_receive_option_reply(ioc, NBD_OPT_STARTTLS, &reply, errp) < 0) { return NULL; } if (reply.type != NBD_REP_ACK) { error_setg(errp, "Server rejected request to start TLS %" PRIx32, reply.type); nbd_send_opt_abort(ioc); return NULL; } if (reply.length != 0) { error_setg(errp, "Start TLS response was not zero %" PRIu32, reply.length); nbd_send_opt_abort(ioc); return NULL; } trace_nbd_receive_starttls_new_client(); tioc = qio_channel_tls_new_client(ioc, tlscreds, hostname, errp); if (!tioc) { return NULL; } qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-client-tls"); data.loop = g_main_loop_new(g_main_context_default(), FALSE); trace_nbd_receive_starttls_tls_handshake(); qio_channel_tls_handshake(tioc, nbd_tls_handshake, &data, NULL); if (!data.complete) { g_main_loop_run(data.loop); } g_main_loop_unref(data.loop); if (data.error) { error_propagate(errp, data.error); object_unref(OBJECT(tioc)); return NULL; } return QIO_CHANNEL(tioc); }
/* Returns -1 if NBD_OPT_GO proves the export @wantname cannot be * used, 0 if NBD_OPT_GO is unsupported (fall back to NBD_OPT_LIST and * NBD_OPT_EXPORT_NAME in that case), and > 0 if the export is good to * go (with @info populated). */ static int nbd_opt_go(QIOChannel *ioc, const char *wantname, NBDExportInfo *info, Error **errp) { nbd_opt_reply reply; uint32_t len = strlen(wantname); uint16_t type; int error; char *buf; /* The protocol requires that the server send NBD_INFO_EXPORT with * a non-zero flags (at least NBD_FLAG_HAS_FLAGS must be set); so * flags still 0 is a witness of a broken server. */ info->flags = 0; trace_nbd_opt_go_start(wantname); buf = g_malloc(4 + len + 2 + 2 * info->request_sizes + 1); stl_be_p(buf, len); memcpy(buf + 4, wantname, len); /* At most one request, everything else up to server */ stw_be_p(buf + 4 + len, info->request_sizes); if (info->request_sizes) { stw_be_p(buf + 4 + len + 2, NBD_INFO_BLOCK_SIZE); } error = nbd_send_option_request(ioc, NBD_OPT_GO, 4 + len + 2 + 2 * info->request_sizes, buf, errp); g_free(buf); if (error < 0) { return -1; } while (1) { if (nbd_receive_option_reply(ioc, NBD_OPT_GO, &reply, errp) < 0) { return -1; } error = nbd_handle_reply_err(ioc, &reply, errp); if (error <= 0) { return error; } len = reply.length; if (reply.type == NBD_REP_ACK) { /* Server is done sending info and moved into transmission phase, but make sure it sent flags */ if (len) { error_setg(errp, "server sent invalid NBD_REP_ACK"); return -1; } if (!info->flags) { error_setg(errp, "broken server omitted NBD_INFO_EXPORT"); return -1; } trace_nbd_opt_go_success(); return 1; } if (reply.type != NBD_REP_INFO) { error_setg(errp, "unexpected reply type %" PRIx32 " (%s), expected %x", reply.type, nbd_rep_lookup(reply.type), NBD_REP_INFO); nbd_send_opt_abort(ioc); return -1; } if (len < sizeof(type)) { error_setg(errp, "NBD_REP_INFO length %" PRIu32 " is too short", len); nbd_send_opt_abort(ioc); return -1; } if (nbd_read(ioc, &type, sizeof(type), errp) < 0) { error_prepend(errp, "failed to read info type"); nbd_send_opt_abort(ioc); return -1; } len -= sizeof(type); be16_to_cpus(&type); switch (type) { case NBD_INFO_EXPORT: if (len != sizeof(info->size) + sizeof(info->flags)) { error_setg(errp, "remaining export info len %" PRIu32 " is unexpected size", len); nbd_send_opt_abort(ioc); return -1; } if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) { error_prepend(errp, "failed to read info size"); nbd_send_opt_abort(ioc); return -1; } be64_to_cpus(&info->size); if (nbd_read(ioc, &info->flags, sizeof(info->flags), errp) < 0) { error_prepend(errp, "failed to read info flags"); nbd_send_opt_abort(ioc); return -1; } be16_to_cpus(&info->flags); trace_nbd_receive_negotiate_size_flags(info->size, info->flags); break; case NBD_INFO_BLOCK_SIZE: if (len != sizeof(info->min_block) * 3) { error_setg(errp, "remaining export info len %" PRIu32 " is unexpected size", len); nbd_send_opt_abort(ioc); return -1; } if (nbd_read(ioc, &info->min_block, sizeof(info->min_block), errp) < 0) { error_prepend(errp, "failed to read info minimum block size"); nbd_send_opt_abort(ioc); return -1; } be32_to_cpus(&info->min_block); if (!is_power_of_2(info->min_block)) { error_setg(errp, "server minimum block size %" PRId32 "is not a power of two", info->min_block); nbd_send_opt_abort(ioc); return -1; } if (nbd_read(ioc, &info->opt_block, sizeof(info->opt_block), errp) < 0) { error_prepend(errp, "failed to read info preferred block size"); nbd_send_opt_abort(ioc); return -1; } be32_to_cpus(&info->opt_block); if (!is_power_of_2(info->opt_block) || info->opt_block < info->min_block) { error_setg(errp, "server preferred block size %" PRId32 "is not valid", info->opt_block); nbd_send_opt_abort(ioc); return -1; } if (nbd_read(ioc, &info->max_block, sizeof(info->max_block), errp) < 0) { error_prepend(errp, "failed to read info maximum block size"); nbd_send_opt_abort(ioc); return -1; } be32_to_cpus(&info->max_block); trace_nbd_opt_go_info_block_size(info->min_block, info->opt_block, info->max_block); break; default: trace_nbd_opt_go_info_unknown(type, nbd_info_lookup(type)); if (nbd_drop(ioc, len, errp) < 0) { error_prepend(errp, "Failed to read info payload"); nbd_send_opt_abort(ioc); return -1; } break; } } }
/* Process another portion of the NBD_OPT_LIST reply. Set *@match if * the current reply matches @want or if the server does not support * NBD_OPT_LIST, otherwise leave @match alone. Return 0 if iteration * is complete, positive if more replies are expected, or negative * with @errp set if an unrecoverable error occurred. */ static int nbd_receive_list(QIOChannel *ioc, const char *want, bool *match, Error **errp) { nbd_opt_reply reply; uint32_t len; uint32_t namelen; char name[NBD_MAX_NAME_SIZE + 1]; int error; if (nbd_receive_option_reply(ioc, NBD_OPT_LIST, &reply, errp) < 0) { return -1; } error = nbd_handle_reply_err(ioc, &reply, errp); if (error <= 0) { /* The server did not support NBD_OPT_LIST, so set *match on * the assumption that any name will be accepted. */ *match = true; return error; } len = reply.length; if (reply.type == NBD_REP_ACK) { if (len != 0) { error_setg(errp, "length too long for option end"); nbd_send_opt_abort(ioc); return -1; } return 0; } else if (reply.type != NBD_REP_SERVER) { error_setg(errp, "Unexpected reply type %" PRIx32 " expected %x", reply.type, NBD_REP_SERVER); nbd_send_opt_abort(ioc); return -1; } if (len < sizeof(namelen) || len > NBD_MAX_BUFFER_SIZE) { error_setg(errp, "incorrect option length %" PRIu32, len); nbd_send_opt_abort(ioc); return -1; } if (nbd_read(ioc, &namelen, sizeof(namelen), errp) < 0) { error_prepend(errp, "failed to read option name length"); nbd_send_opt_abort(ioc); return -1; } namelen = be32_to_cpu(namelen); len -= sizeof(namelen); if (len < namelen) { error_setg(errp, "incorrect option name length"); nbd_send_opt_abort(ioc); return -1; } if (namelen != strlen(want)) { if (nbd_drop(ioc, len, errp) < 0) { error_prepend(errp, "failed to skip export name with wrong length"); nbd_send_opt_abort(ioc); return -1; } return 1; } assert(namelen < sizeof(name)); if (nbd_read(ioc, name, namelen, errp) < 0) { error_prepend(errp, "failed to read export name"); nbd_send_opt_abort(ioc); return -1; } name[namelen] = '\0'; len -= namelen; if (nbd_drop(ioc, len, errp) < 0) { error_prepend(errp, "failed to read export description"); nbd_send_opt_abort(ioc); return -1; } if (!strcmp(name, want)) { *match = true; } return 1; }