mirror of
https://git.tartarus.org/simon/putty.git
synced 2025-01-09 17:38:00 +00:00
f081885bc0
misc.c has always contained a combination of things that are tied tightly into the PuTTY code base (e.g. they use the conf system, or work with our sockets abstraction) and things that are pure standalone utility functions like nullstrcmp() which could quite happily be dropped into any C program without causing a link failure. Now the latter kind of standalone utility code lives in the new source file utils.c, whose only external dependency is on memory.c (for snew, sfree etc), which in turn requires the user to provide an out_of_memory() function. So it should now be much easier to link test programs that use PuTTY's low-level functions without also pulling in half its bulky infrastructure. In the process, I came across a memory allocation logging system enabled by -DMALLOC_LOG that looks long since bit-rotted; in any case we have much more advanced tools for that kind of thing these days, like valgrind and Leak Sanitiser, so I've just removed it rather than trying to transplant it somewhere sensible. (We can always pull it back out of the version control history if really necessary, but I haven't used it in at least a decade.) The other slightly silly thing I did was to give bufchain a function pointer field that points to queue_idempotent_callback(), and disallow direct setting of the 'ic' field in favour of calling bufchain_set_callback which will fill that pointer in too. That allows the bufchain system to live in utils.c rather than misc.c, so that programs can use it without also having to link in the callback system or provide an annoying stub of that function. In fact that's just allowed me to remove stubs of that kind from PuTTYgen and Pageant!
469 lines
14 KiB
C
469 lines
14 KiB
C
/*
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* Top-level code for SSH server implementation.
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*/
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#include <assert.h>
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#include <stddef.h>
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#include "putty.h"
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#include "ssh.h"
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#include "sshbpp.h"
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#include "sshppl.h"
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#include "sshserver.h"
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#ifndef NO_GSSAPI
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#include "sshgssc.h"
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#include "sshgss.h"
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#endif
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struct Ssh { int dummy; };
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typedef struct server server;
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struct server {
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bufchain in_raw, out_raw;
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IdempotentCallback ic_out_raw;
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bufchain dummy_user_input; /* we never put anything on this */
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PacketLogSettings pls;
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LogContext *logctx;
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struct DataTransferStats stats;
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int remote_bugs;
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Socket *socket;
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Plug plug;
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int conn_throttle_count;
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bool frozen;
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Conf *conf;
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ssh_key *const *hostkeys;
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int nhostkeys;
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struct RSAKey *hostkey1;
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AuthPolicy *authpolicy;
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const SftpServerVtable *sftpserver_vt;
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Seat seat;
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Ssh ssh;
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struct ssh_version_receiver version_receiver;
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BinaryPacketProtocol *bpp;
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PacketProtocolLayer *base_layer;
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ConnectionLayer *cl;
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struct ssh_connection_shared_gss_state gss_state;
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};
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static void ssh_server_free_callback(void *vsrv);
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static void server_got_ssh_version(struct ssh_version_receiver *rcv,
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int major_version);
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static void server_connect_bpp(server *srv);
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static void server_bpp_output_raw_data_callback(void *vctx);
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void share_activate(ssh_sharing_state *sharestate,
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const char *server_verstring) {}
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void ssh_connshare_provide_connlayer(ssh_sharing_state *sharestate,
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ConnectionLayer *cl) {}
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int share_ndownstreams(ssh_sharing_state *sharestate) { return 0; }
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void share_got_pkt_from_server(ssh_sharing_connstate *cs, int type,
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const void *vpkt, int pktlen) {}
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void share_setup_x11_channel(ssh_sharing_connstate *cs, share_channel *chan,
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unsigned upstream_id, unsigned server_id,
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unsigned server_currwin, unsigned server_maxpkt,
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unsigned client_adjusted_window,
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const char *peer_addr, int peer_port, int endian,
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int protomajor, int protominor,
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const void *initial_data, int initial_len) {}
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Channel *agentf_new(SshChannel *c) { return NULL; }
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bool agent_exists(void) { return false; }
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void ssh_got_exitcode(Ssh *ssh, int exitcode) {}
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mainchan *mainchan_new(
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PacketProtocolLayer *ppl, ConnectionLayer *cl, Conf *conf,
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int term_width, int term_height, int is_simple, SshChannel **sc_out)
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{ return NULL; }
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void mainchan_get_specials(
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mainchan *mc, add_special_fn_t add_special, void *ctx) {}
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void mainchan_special_cmd(mainchan *mc, SessionSpecialCode code, int arg) {}
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void mainchan_terminal_size(mainchan *mc, int width, int height) {}
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/* Seat functions to ensure we don't get choosy about crypto - as the
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* server, it's not up to us to give user warnings */
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static int server_confirm_weak_crypto_primitive(
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Seat *seat, const char *algtype, const char *algname,
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void (*callback)(void *ctx, int result), void *ctx) { return 1; }
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static int server_confirm_weak_cached_hostkey(
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Seat *seat, const char *algname, const char *betteralgs,
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void (*callback)(void *ctx, int result), void *ctx) { return 1; }
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static const SeatVtable server_seat_vt = {
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nullseat_output,
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nullseat_eof,
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nullseat_get_userpass_input,
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nullseat_notify_remote_exit,
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nullseat_connection_fatal,
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nullseat_update_specials_menu,
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nullseat_get_ttymode,
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nullseat_set_busy_status,
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nullseat_verify_ssh_host_key,
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server_confirm_weak_crypto_primitive,
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server_confirm_weak_cached_hostkey,
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nullseat_is_never_utf8,
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nullseat_echoedit_update,
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nullseat_get_x_display,
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nullseat_get_windowid,
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nullseat_get_window_pixel_size,
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};
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static void server_socket_log(Plug *plug, int type, SockAddr *addr, int port,
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const char *error_msg, int error_code)
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{
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/* server *srv = container_of(plug, server, plug); */
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/* FIXME */
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}
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static void server_closing(Plug *plug, const char *error_msg, int error_code,
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bool calling_back)
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{
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server *srv = container_of(plug, server, plug);
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if (error_msg) {
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ssh_remote_error(&srv->ssh, "Network error: %s", error_msg);
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} else if (srv->bpp) {
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srv->bpp->input_eof = true;
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queue_idempotent_callback(&srv->bpp->ic_in_raw);
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}
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}
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static void server_receive(Plug *plug, int urgent, char *data, int len)
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{
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server *srv = container_of(plug, server, plug);
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/* Log raw data, if we're in that mode. */
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if (srv->logctx)
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log_packet(srv->logctx, PKT_INCOMING, -1, NULL, data, len,
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0, NULL, NULL, 0, NULL);
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bufchain_add(&srv->in_raw, data, len);
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if (!srv->frozen && srv->bpp)
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queue_idempotent_callback(&srv->bpp->ic_in_raw);
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}
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static void server_sent(Plug *plug, int bufsize)
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{
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#ifdef FIXME
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server *srv = container_of(plug, server, plug);
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/*
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* If the send backlog on the SSH socket itself clears, we should
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* unthrottle the whole world if it was throttled. Also trigger an
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* extra call to the consumer of the BPP's output, to try to send
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* some more data off its bufchain.
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*/
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if (bufsize < SSH_MAX_BACKLOG) {
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srv_throttle_all(srv, 0, bufsize);
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queue_idempotent_callback(&srv->ic_out_raw);
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}
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#endif
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}
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LogContext *ssh_get_logctx(Ssh *ssh)
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{
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server *srv = container_of(ssh, server, ssh);
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return srv->logctx;
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}
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void ssh_throttle_conn(Ssh *ssh, int adjust)
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{
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server *srv = container_of(ssh, server, ssh);
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int old_count = srv->conn_throttle_count;
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bool frozen;
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srv->conn_throttle_count += adjust;
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assert(srv->conn_throttle_count >= 0);
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if (srv->conn_throttle_count && !old_count) {
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frozen = true;
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} else if (!srv->conn_throttle_count && old_count) {
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frozen = false;
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} else {
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return; /* don't change current frozen state */
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}
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srv->frozen = frozen;
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if (srv->socket) {
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sk_set_frozen(srv->socket, frozen);
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/*
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* Now process any SSH connection data that was stashed in our
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* queue while we were frozen.
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*/
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queue_idempotent_callback(&srv->bpp->ic_in_raw);
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}
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}
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static const PlugVtable ssh_server_plugvt = {
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server_socket_log,
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server_closing,
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server_receive,
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server_sent,
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NULL
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};
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Plug *ssh_server_plug(
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Conf *conf, ssh_key *const *hostkeys, int nhostkeys,
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struct RSAKey *hostkey1, AuthPolicy *authpolicy, LogPolicy *logpolicy,
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const SftpServerVtable *sftpserver_vt)
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{
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server *srv = snew(server);
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memset(srv, 0, sizeof(server));
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srv->plug.vt = &ssh_server_plugvt;
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srv->conf = conf_copy(conf);
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srv->logctx = log_init(logpolicy, conf);
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conf_set_bool(srv->conf, CONF_ssh_no_shell, true);
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srv->nhostkeys = nhostkeys;
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srv->hostkeys = hostkeys;
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srv->hostkey1 = hostkey1;
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srv->authpolicy = authpolicy;
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srv->sftpserver_vt = sftpserver_vt;
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srv->seat.vt = &server_seat_vt;
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bufchain_init(&srv->in_raw);
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bufchain_init(&srv->out_raw);
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bufchain_init(&srv->dummy_user_input);
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/* FIXME: replace with sensible */
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srv->gss_state.libs = snew(struct ssh_gss_liblist);
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srv->gss_state.libs->nlibraries = 0;
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return &srv->plug;
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}
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void ssh_server_start(Plug *plug, Socket *socket)
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{
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server *srv = container_of(plug, server, plug);
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const char *our_protoversion;
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if (srv->hostkey1 && srv->nhostkeys) {
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our_protoversion = "1.99"; /* offer both SSH-1 and SSH-2 */
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} else if (srv->hostkey1) {
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our_protoversion = "1.5"; /* SSH-1 only */
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} else {
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assert(srv->nhostkeys);
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our_protoversion = "2.0"; /* SSH-2 only */
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}
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srv->socket = socket;
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srv->ic_out_raw.fn = server_bpp_output_raw_data_callback;
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srv->ic_out_raw.ctx = srv;
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srv->version_receiver.got_ssh_version = server_got_ssh_version;
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srv->bpp = ssh_verstring_new(
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srv->conf, srv->logctx, false /* bare_connection */,
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our_protoversion, &srv->version_receiver,
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true, "Uppity");
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server_connect_bpp(srv);
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queue_idempotent_callback(&srv->bpp->ic_in_raw);
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}
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static void ssh_server_free_callback(void *vsrv)
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{
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server *srv = (server *)vsrv;
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bufchain_clear(&srv->in_raw);
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bufchain_clear(&srv->out_raw);
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bufchain_clear(&srv->dummy_user_input);
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sk_close(srv->socket);
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if (srv->bpp)
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ssh_bpp_free(srv->bpp);
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delete_callbacks_for_context(srv);
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conf_free(srv->conf);
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log_free(srv->logctx);
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sfree(srv->gss_state.libs); /* FIXME: replace with sensible */
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sfree(srv);
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server_instance_terminated();
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}
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static void server_connect_bpp(server *srv)
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{
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srv->bpp->ssh = &srv->ssh;
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srv->bpp->in_raw = &srv->in_raw;
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srv->bpp->out_raw = &srv->out_raw;
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bufchain_set_callback(srv->bpp->out_raw, &srv->ic_out_raw);
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srv->bpp->pls = &srv->pls;
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srv->bpp->logctx = srv->logctx;
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srv->bpp->remote_bugs = srv->remote_bugs;
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/* Servers don't really have a notion of 'unexpected' connection
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* closure. The client is free to close if it likes. */
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srv->bpp->expect_close = true;
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}
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static void server_connect_ppl(server *srv, PacketProtocolLayer *ppl)
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{
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ppl->bpp = srv->bpp;
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ppl->user_input = &srv->dummy_user_input;
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ppl->logctx = srv->logctx;
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ppl->ssh = &srv->ssh;
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ppl->seat = &srv->seat;
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ppl->remote_bugs = srv->remote_bugs;
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}
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static void server_bpp_output_raw_data_callback(void *vctx)
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{
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server *srv = (server *)vctx;
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if (!srv->socket)
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return;
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while (bufchain_size(&srv->out_raw) > 0) {
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void *data;
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int len, backlog;
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bufchain_prefix(&srv->out_raw, &data, &len);
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if (srv->logctx)
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log_packet(srv->logctx, PKT_OUTGOING, -1, NULL, data, len,
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0, NULL, NULL, 0, NULL);
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backlog = sk_write(srv->socket, data, len);
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bufchain_consume(&srv->out_raw, len);
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if (backlog > SSH_MAX_BACKLOG) {
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#ifdef FIXME
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ssh_throttle_all(ssh, 1, backlog);
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#endif
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return;
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}
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}
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#ifdef FIXME
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if (ssh->pending_close) {
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sk_close(ssh->s);
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ssh->s = NULL;
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}
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#endif
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}
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#define LOG_FORMATTED_MSG(logctx, fmt) do \
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{ \
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va_list ap; \
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va_start(ap, fmt); \
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logeventvf(logctx, fmt, ap); \
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va_end(ap); \
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} while (0)
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void ssh_remote_error(Ssh *ssh, const char *fmt, ...)
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{
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server *srv = container_of(ssh, server, ssh);
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LOG_FORMATTED_MSG(srv->logctx, fmt);
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queue_toplevel_callback(ssh_server_free_callback, srv);
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}
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void ssh_remote_eof(Ssh *ssh, const char *fmt, ...)
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{
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server *srv = container_of(ssh, server, ssh);
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LOG_FORMATTED_MSG(srv->logctx, fmt);
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queue_toplevel_callback(ssh_server_free_callback, srv);
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}
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void ssh_proto_error(Ssh *ssh, const char *fmt, ...)
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{
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server *srv = container_of(ssh, server, ssh);
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LOG_FORMATTED_MSG(srv->logctx, fmt);
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queue_toplevel_callback(ssh_server_free_callback, srv);
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}
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void ssh_sw_abort(Ssh *ssh, const char *fmt, ...)
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{
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server *srv = container_of(ssh, server, ssh);
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LOG_FORMATTED_MSG(srv->logctx, fmt);
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queue_toplevel_callback(ssh_server_free_callback, srv);
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}
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void ssh_user_close(Ssh *ssh, const char *fmt, ...)
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{
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server *srv = container_of(ssh, server, ssh);
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LOG_FORMATTED_MSG(srv->logctx, fmt);
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queue_toplevel_callback(ssh_server_free_callback, srv);
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}
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static void server_got_ssh_version(struct ssh_version_receiver *rcv,
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int major_version)
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{
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server *srv = container_of(rcv, server, version_receiver);
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BinaryPacketProtocol *old_bpp;
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PacketProtocolLayer *connection_layer;
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old_bpp = srv->bpp;
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srv->remote_bugs = ssh_verstring_get_bugs(old_bpp);
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if (major_version == 2) {
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PacketProtocolLayer *userauth_layer, *transport_child_layer;
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srv->bpp = ssh2_bpp_new(srv->logctx, &srv->stats, true);
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server_connect_bpp(srv);
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connection_layer = ssh2_connection_new(
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&srv->ssh, NULL, false, srv->conf,
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ssh_verstring_get_local(old_bpp), &srv->cl);
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ssh2connection_server_configure(connection_layer, srv->sftpserver_vt);
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server_connect_ppl(srv, connection_layer);
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if (conf_get_bool(srv->conf, CONF_ssh_no_userauth)) {
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userauth_layer = NULL;
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transport_child_layer = connection_layer;
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} else {
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userauth_layer = ssh2_userauth_server_new(
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connection_layer, srv->authpolicy);
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server_connect_ppl(srv, userauth_layer);
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transport_child_layer = userauth_layer;
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}
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srv->base_layer = ssh2_transport_new(
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srv->conf, NULL, 0, NULL,
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ssh_verstring_get_remote(old_bpp),
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ssh_verstring_get_local(old_bpp),
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&srv->gss_state, &srv->stats, transport_child_layer, true);
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ssh2_transport_provide_hostkeys(
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srv->base_layer, srv->hostkeys, srv->nhostkeys);
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if (userauth_layer)
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ssh2_userauth_server_set_transport_layer(
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userauth_layer, srv->base_layer);
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server_connect_ppl(srv, srv->base_layer);
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} else {
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srv->bpp = ssh1_bpp_new(srv->logctx);
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server_connect_bpp(srv);
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connection_layer = ssh1_connection_new(&srv->ssh, srv->conf, &srv->cl);
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server_connect_ppl(srv, connection_layer);
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srv->base_layer = ssh1_login_server_new(
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connection_layer, srv->hostkey1, srv->authpolicy);
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server_connect_ppl(srv, srv->base_layer);
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}
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/* Connect the base layer - whichever it is - to the BPP, and set
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* up its selfptr. */
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srv->base_layer->selfptr = &srv->base_layer;
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ssh_ppl_setup_queues(srv->base_layer, &srv->bpp->in_pq, &srv->bpp->out_pq);
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#ifdef FIXME // we probably will want one of these, in the end
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srv->pinger = pinger_new(srv->conf, &srv->backend);
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#endif
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queue_idempotent_callback(&srv->bpp->ic_in_raw);
|
|
ssh_ppl_process_queue(srv->base_layer);
|
|
|
|
ssh_bpp_free(old_bpp);
|
|
}
|