Reworking of packet delivery to coroutines in SSH-2.
[u/mdw/putty] / ssh.c
diff --git a/ssh.c b/ssh.c
index f39894a..ae49ba1 100644 (file)
--- a/ssh.c
+++ b/ssh.c
@@ -431,10 +431,12 @@ enum {
  *    Database for Edit and Continue'.
  */
 #define crBegin(v)     { int *crLine = &v; switch(v) { case 0:;
-#define crState(t) \
-    struct t *s; \
-    if (!ssh->t) ssh->t = snew(struct t); \
-    s = ssh->t;
+#define crBeginState   crBegin(s->crLine)
+#define crStateP(t, v)                         \
+    struct t *s;                               \
+    if (!(v)) { s = (v) = snew(struct t); s->crLine = 0; }     \
+    s = (v);
+#define crState(t)     crStateP(t, ssh->t)
 #define crFinish(z)    } *crLine = 0; return (z); }
 #define crFinishV      } *crLine = 0; return; }
 #define crReturn(z)    \
@@ -888,12 +890,8 @@ struct ssh_tag {
 
     int ssh1_rdpkt_crstate;
     int ssh2_rdpkt_crstate;
-    int do_ssh_init_crstate;
     int ssh_gotdata_crstate;
-    int do_ssh1_login_crstate;
     int do_ssh1_connection_crstate;
-    int do_ssh2_transport_crstate;
-    int do_ssh2_authconn_crstate;
 
     void *do_ssh_init_state;
     void *do_ssh1_login_state;
@@ -962,6 +960,7 @@ struct ssh_tag {
      * indications from a request.
      */
     struct queued_handler *qhead, *qtail;
+    handler_fn_t q_saved_handler1, q_saved_handler2;
 
     /*
      * This module deals with sending keepalives.
@@ -2659,6 +2658,7 @@ static void ssh_send_verstring(Ssh ssh, char *svers)
 static int do_ssh_init(Ssh ssh, unsigned char c)
 {
     struct do_ssh_init_state {
+       int crLine;
        int vslen;
        char version[10];
        char *vstring;
@@ -2667,8 +2667,8 @@ static int do_ssh_init(Ssh ssh, unsigned char c)
        int proto1, proto2;
     };
     crState(do_ssh_init_state);
-
-    crBegin(ssh->do_ssh_init_crstate);
+    
+    crBeginState;
 
     /* Search for a line beginning with the string "SSH-" in the input. */
     for (;;) {
@@ -3257,6 +3257,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
     struct RSAKey servkey, hostkey;
     struct MD5Context md5c;
     struct do_ssh1_login_state {
+       int crLine;
        int len;
        unsigned char *rsabuf, *keystr1, *keystr2;
        unsigned long supported_ciphers_mask, supported_auths_mask;
@@ -3284,7 +3285,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
     };
     crState(do_ssh1_login_state);
 
-    crBegin(ssh->do_ssh1_login_crstate);
+    crBeginState;
 
     if (!pktin)
        crWaitUntil(pktin);
@@ -4353,27 +4354,26 @@ static void ssh_queueing_handler(Ssh ssh, struct Packet *pktin)
 
     if (qh->msg1 > 0) {
        assert(ssh->packet_dispatch[qh->msg1] == ssh_queueing_handler);
-       ssh->packet_dispatch[qh->msg1] = NULL;
+       ssh->packet_dispatch[qh->msg1] = ssh->q_saved_handler1;
     }
     if (qh->msg2 > 0) {
        assert(ssh->packet_dispatch[qh->msg2] == ssh_queueing_handler);
-       ssh->packet_dispatch[qh->msg2] = NULL;
+       ssh->packet_dispatch[qh->msg2] = ssh->q_saved_handler2;
     }
 
     if (qh->next) {
        ssh->qhead = qh->next;
 
        if (ssh->qhead->msg1 > 0) {
-           assert(ssh->packet_dispatch[ssh->qhead->msg1] == NULL);
+           ssh->q_saved_handler1 = ssh->packet_dispatch[ssh->qhead->msg1];
            ssh->packet_dispatch[ssh->qhead->msg1] = ssh_queueing_handler;
        }
        if (ssh->qhead->msg2 > 0) {
-           assert(ssh->packet_dispatch[ssh->qhead->msg2] == NULL);
+           ssh->q_saved_handler2 = ssh->packet_dispatch[ssh->qhead->msg2];
            ssh->packet_dispatch[ssh->qhead->msg2] = ssh_queueing_handler;
        }
     } else {
        ssh->qhead = ssh->qtail = NULL;
-       ssh->packet_dispatch[pktin->type] = NULL;
     }
 
     qh->handler(ssh, pktin, qh->ctx);
@@ -4397,11 +4397,11 @@ static void ssh_queue_handler(Ssh ssh, int msg1, int msg2,
        ssh->qhead = qh;
 
        if (qh->msg1 > 0) {
-           assert(ssh->packet_dispatch[qh->msg1] == NULL);
+           ssh->q_saved_handler1 = ssh->packet_dispatch[ssh->qhead->msg1];
            ssh->packet_dispatch[qh->msg1] = ssh_queueing_handler;
        }
        if (qh->msg2 > 0) {
-           assert(ssh->packet_dispatch[qh->msg2] == NULL);
+           ssh->q_saved_handler2 = ssh->packet_dispatch[ssh->qhead->msg2];
            ssh->packet_dispatch[qh->msg2] = ssh_queueing_handler;
        }
     } else {
@@ -4959,13 +4959,16 @@ static void ssh1_msg_channel_close(Ssh ssh, struct Packet *pktin)
                     x11_send_eof(c->u.x11.s);
                 else
                     send_close = TRUE;
+               break;
               case CHAN_SOCKDATA:
                 if (c->u.pfd.s)
-                    x11_send_eof(c->u.pfd.s);
+                    pfd_send_eof(c->u.pfd.s);
                 else
                     send_close = TRUE;
+               break;
               case CHAN_AGENT:
                 send_close = TRUE;
+               break;
             }
 
             if (send_close && !(c->closes & CLOSES_SENT_EOF)) {
@@ -5475,6 +5478,7 @@ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
 {
     unsigned char *in = (unsigned char *)vin;
     struct do_ssh2_transport_state {
+       int crLine;
        int nbits, pbits, warn_kex, warn_cscipher, warn_sccipher;
        Bignum p, g, e, f, K;
        void *our_kexinit;
@@ -5508,7 +5512,7 @@ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
     };
     crState(do_ssh2_transport_state);
 
-    crBegin(ssh->do_ssh2_transport_crstate);
+    crBeginState;
 
     s->cscipher_tobe = s->sccipher_tobe = NULL;
     s->csmac_tobe = s->scmac_tobe = NULL;
@@ -6406,19 +6410,6 @@ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
                                         ssh2_timer, ssh);
 
     /*
-     * If this is the first key exchange phase, we must pass the
-     * SSH2_MSG_NEWKEYS packet to the next layer, not because it
-     * wants to see it but because it will need time to initialise
-     * itself before it sees an actual packet. In subsequent key
-     * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
-     * it would only confuse the layer above.
-     */
-    if (s->activated_authconn) {
-       crReturn(0);
-    }
-    s->activated_authconn = TRUE;
-
-    /*
      * Now we're encrypting. Begin returning 1 to the protocol main
      * function so that other things can run on top of the
      * transport. If we ever see a KEXINIT, we must go back to the
@@ -6436,6 +6427,13 @@ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
     while (!((pktin && pktin->type == SSH2_MSG_KEXINIT) ||
             (!pktin && inlen < 0))) {
         wait_for_rekey:
+       if (!ssh->protocol_initial_phase_done) {
+           ssh->protocol_initial_phase_done = TRUE;
+           /*
+            * Allow authconn to initialise itself.
+            */
+           do_ssh2_authconn(ssh, NULL, 0, NULL);
+       }
        crReturn(1);
     }
     if (pktin) {
@@ -7470,10 +7468,16 @@ static void ssh2_send_ttymode(void *data, char *mode, char *val)
 /*
  * Handle the SSH-2 userauth and connection layers.
  */
+static void ssh2_msg_authconn(Ssh ssh, struct Packet *pktin)
+{
+    do_ssh2_authconn(ssh, NULL, 0, pktin);
+}
+
 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                             struct Packet *pktin)
 {
     struct do_ssh2_authconn_state {
+       int crLine;
        enum {
            AUTH_TYPE_NONE,
                AUTH_TYPE_PUBLICKEY,
@@ -7529,8 +7533,33 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
     };
     crState(do_ssh2_authconn_state);
 
-    crBegin(ssh->do_ssh2_authconn_crstate);
-
+    crBeginState;
+
+    /* Register as a handler for all the messages this coroutine handles. */
+    ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = ssh2_msg_authconn;
+    /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = ssh2_msg_authconn; duplicate case value */
+    /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = ssh2_msg_authconn; duplicate case value */
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_authconn;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_authconn;
+    
     s->done_service_req = FALSE;
     s->we_are_in = s->userauth_success = FALSE;
 #ifndef NO_GSSAPI
@@ -9362,6 +9391,24 @@ static void ssh2_msg_debug(Ssh ssh, struct Packet *pktin)
     logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
 }
 
+static void ssh2_msg_transport(Ssh ssh, struct Packet *pktin)
+{
+    do_ssh2_transport(ssh, NULL, 0, pktin);
+}
+
+/*
+ * Called if we receive a packet that isn't allowed by the protocol.
+ * This only applies to packets whose meaning PuTTY understands.
+ * Entirely unknown packets are handled below.
+ */
+static void ssh2_msg_unexpected(Ssh ssh, struct Packet *pktin)
+{
+    char *buf = dupprintf("Server protocol violation: unexpected %s packet",
+                         ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
+                                       pktin->type));
+    ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
+}
+
 static void ssh2_msg_something_unimplemented(Ssh ssh, struct Packet *pktin)
 {
     struct Packet *pktout;
@@ -9388,45 +9435,47 @@ static void ssh2_protocol_setup(Ssh ssh)
        ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented;
 
     /*
-     * Any message we actually understand, we set to NULL so that
-     * the coroutines will get it.
+     * Initially, we only accept transport messages (and a few generic
+     * ones).  do_ssh2_authconn will add more when it starts.
+     * Messages that are understood but not currently acceptable go to
+     * ssh2_msg_unexpected.
      */
-    ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_SERVICE_REQUEST] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_KEXINIT] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_NEWKEYS] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_KEXDH_INIT] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_KEXDH_REPLY] = NULL;
-    /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REQUEST] = NULL; duplicate case value */
-    /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_GROUP] = NULL; duplicate case value */
-    ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_INIT] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REPLY] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = NULL;
-    /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = NULL; duplicate case value */
-    /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = NULL; duplicate case value */
-    ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = NULL;
-    ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_SERVICE_REQUEST] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_KEXINIT] = ssh2_msg_transport;
+    ssh->packet_dispatch[SSH2_MSG_NEWKEYS] = ssh2_msg_transport;
+    ssh->packet_dispatch[SSH2_MSG_KEXDH_INIT] = ssh2_msg_transport;
+    ssh->packet_dispatch[SSH2_MSG_KEXDH_REPLY] = ssh2_msg_transport;
+    /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REQUEST] = ssh2_msg_transport; duplicate case value */
+    /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_GROUP] = ssh2_msg_transport; duplicate case value */
+    ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_INIT] = ssh2_msg_transport;
+    ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REPLY] = ssh2_msg_transport;
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = ssh2_msg_unexpected;
+    /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = ssh2_msg_unexpected; duplicate case value */
+    /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = ssh2_msg_unexpected; duplicate case value */
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_unexpected;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_unexpected;
 
     /*
-     * These special message types we install handlers for.
+     * These messages have a special handler from the start.
      */
     ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect;
     ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore; /* shared with SSH-1 */
@@ -9461,24 +9510,12 @@ static void ssh2_protocol(Ssh ssh, void *vin, int inlen,
            do_ssh2_transport(ssh, "too much data received", -1, NULL);
     }
 
-    if (pktin && ssh->packet_dispatch[pktin->type]) {
+    if (pktin)
        ssh->packet_dispatch[pktin->type](ssh, pktin);
-       return;
-    }
-
-    if (!ssh->protocol_initial_phase_done ||
-       (pktin && pktin->type >= 20 && pktin->type < 50)) {
-       if (do_ssh2_transport(ssh, in, inlen, pktin) &&
-           !ssh->protocol_initial_phase_done) {
-           ssh->protocol_initial_phase_done = TRUE;
-           /*
-            * Allow authconn to initialise itself.
-            */
-           do_ssh2_authconn(ssh, NULL, 0, NULL);
-       }
-    } else {
+    else if (!ssh->protocol_initial_phase_done)
+       do_ssh2_transport(ssh, in, inlen, pktin);
+    else
        do_ssh2_authconn(ssh, in, inlen, pktin);
-    }
 }
 
 static void ssh_cache_conf_values(Ssh ssh)
@@ -9540,12 +9577,8 @@ static const char *ssh_init(void *frontend_handle, void **backend_handle,
     ssh->v2_outgoing_sequence = 0;
     ssh->ssh1_rdpkt_crstate = 0;
     ssh->ssh2_rdpkt_crstate = 0;
-    ssh->do_ssh_init_crstate = 0;
     ssh->ssh_gotdata_crstate = 0;
     ssh->do_ssh1_connection_crstate = 0;
-    ssh->do_ssh1_login_crstate = 0;
-    ssh->do_ssh2_transport_crstate = 0;
-    ssh->do_ssh2_authconn_crstate = 0;
     ssh->do_ssh_init_state = NULL;
     ssh->do_ssh1_login_state = NULL;
     ssh->do_ssh2_transport_state = NULL;