X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=site.c;h=37968896ccb50f1d07370a7ff582d1697a158327;hb=4a6ee8b677fd7addc97fc0d245f95ddde3b5f8e4;hp=df0ab3a46433f41f3f506a00bae751f61cbd5dae;hpb=13b8fbf4548f3457b02afd36e9284d39839d6f85;p=secnet.git

diff --git a/site.c b/site.c
index df0ab3a..3796889 100644
--- a/site.c
+++ b/site.c
@@ -109,6 +109,8 @@
 
 #define CASES_MSG3_KNOWN LABEL_MSG3: case LABEL_MSG3BIS
 
+struct msg;
+
 int32_t site_max_start_pad = 4*4;
 
 static cstring_t state_name(uint32_t state)
@@ -394,15 +396,23 @@ static uint32_t event_log_priority(struct site *st, uint32_t event)
     }
 }
 
+static uint32_t slog_start(struct site *st, uint32_t event)
+{
+    uint32_t class=event_log_priority(st, event);
+    if (class) {
+	slilog_part(st->log,class,"%s: ",st->tunname);
+    }
+    return class;
+}
+
 static void vslog(struct site *st, uint32_t event, cstring_t msg, va_list ap)
 FORMAT(printf,3,0);
 static void vslog(struct site *st, uint32_t event, cstring_t msg, va_list ap)
 {
     uint32_t class;
 
-    class=event_log_priority(st, event);
+    class=slog_start(st,event);
     if (class) {
-	slilog_part(st->log,class,"%s: ",st->tunname);
 	vslilog_part(st->log,class,msg,ap);
 	slilog_part(st->log,class,"\n");
     }
@@ -457,7 +467,9 @@ static bool_t initiate_key_setup(struct site *st, cstring_t reason,
 static void enter_state_run(struct site *st);
 static bool_t enter_state_resolve(struct site *st);
 static void decrement_resolving_count(struct site *st, int by);
-static bool_t enter_new_state(struct site *st,uint32_t next);
+static bool_t enter_new_state(struct site *st,uint32_t next,
+			      const struct msg *prompt
+			      /* may be 0 for SENTMSG1 */);
 static void enter_state_wait(struct site *st);
 static void activate_new_key(struct site *st);
 
@@ -611,7 +623,9 @@ static void append_string_xinfo_done(struct buffer_if *buf,
 
 /* Build any of msg1 to msg4. msg5 and msg6 are built from the inside
    out using a transform of config data supplied by netlink */
-static bool_t generate_msg(struct site *st, uint32_t type, cstring_t what)
+static bool_t generate_msg(struct site *st, uint32_t type, cstring_t what,
+			   const struct msg *prompt
+			   /* may be 0 for MSG1 */)
 {
     string_t dhpub;
     unsigned minor;
@@ -792,14 +806,21 @@ static bool_t check_msg(struct site *st, uint32_t type, struct msg *m,
     return False;
 }
 
-static bool_t generate_msg1(struct site *st)
+static bool_t kex_init(struct site *st)
 {
     st->random->generate(st->random->st,NONCELEN,st->localN);
-    return generate_msg(st,LABEL_MSG1,"site:MSG1");
+    return True;
+}
+
+static bool_t generate_msg1(struct site *st, const struct msg *prompt_maybe_0)
+{
+    return
+	generate_msg(st,LABEL_MSG1,"site:MSG1",prompt_maybe_0);
 }
 
 static bool_t process_msg1(struct site *st, struct buffer_if *msg1,
-			   const struct comm_addr *src, struct msg *m)
+			   const struct comm_addr *src,
+			   const struct msg *m)
 {
     /* We've already determined we're in an appropriate state to
        process an incoming MSG1, and that the MSG1 has correct values
@@ -811,25 +832,26 @@ static bool_t process_msg1(struct site *st, struct buffer_if *msg1,
     return True;
 }
 
-static bool_t generate_msg2(struct site *st)
+static bool_t generate_msg2(struct site *st,
+			    const struct msg *prompt_may_be_null)
 {
-    st->random->generate(st->random->st,NONCELEN,st->localN);
-    return generate_msg(st,LABEL_MSG2,"site:MSG2");
+    return
+	generate_msg(st,LABEL_MSG2,"site:MSG2",prompt_may_be_null);
 }
 
 static bool_t process_msg2(struct site *st, struct buffer_if *msg2,
-			   const struct comm_addr *src)
+			   const struct comm_addr *src,
+			   struct msg *m /* returned */)
 {
-    struct msg m;
     cstring_t err;
 
-    if (!unpick_msg(st,LABEL_MSG2,msg2,&m)) return False;
-    if (!check_msg(st,LABEL_MSG2,&m,&err)) {
+    if (!unpick_msg(st,LABEL_MSG2,msg2,m)) return False;
+    if (!check_msg(st,LABEL_MSG2,m,&err)) {
 	slog(st,LOG_SEC,"msg2: %s",err);
 	return False;
     }
-    st->setup_session_id=m.source;
-    st->remote_capabilities=m.remote_capabilities;
+    st->setup_session_id=m->source;
+    st->remote_capabilities=m->remote_capabilities;
 
     /* Select the transform to use */
 
@@ -860,11 +882,11 @@ kind##_found:								\
 
 #undef CHOOSE_CRYPTO
 
-    memcpy(st->remoteN,m.nR,NONCELEN);
+    memcpy(st->remoteN,m->nR,NONCELEN);
     return True;
 }
 
-static bool_t generate_msg3(struct site *st)
+static bool_t generate_msg3(struct site *st, const struct msg *prompt)
 {
     /* Now we have our nonce and their nonce. Think of a secret key,
        and create message number 3. */
@@ -873,7 +895,7 @@ static bool_t generate_msg3(struct site *st)
 			(st->remote_capabilities & CAPAB_TRANSFORM_MASK)
 			? LABEL_MSG3BIS
 			: LABEL_MSG3,
-			"site:MSG3");
+			"site:MSG3",prompt);
 }
 
 static bool_t process_msg3_msg4(struct site *st, struct msg *m)
@@ -892,9 +914,9 @@ static bool_t process_msg3_msg4(struct site *st, struct msg *m)
 }
 
 static bool_t process_msg3(struct site *st, struct buffer_if *msg3,
-			   const struct comm_addr *src, uint32_t msgtype)
+			   const struct comm_addr *src, uint32_t msgtype,
+			   struct msg *m /* returned */)
 {
-    struct msg m;
     cstring_t err;
 
     switch (msgtype) {
@@ -902,17 +924,17 @@ static bool_t process_msg3(struct site *st, struct buffer_if *msg3,
 	default: assert(0);
     }
 
-    if (!unpick_msg(st,msgtype,msg3,&m)) return False;
-    if (!check_msg(st,msgtype,&m,&err)) {
+    if (!unpick_msg(st,msgtype,msg3,m)) return False;
+    if (!check_msg(st,msgtype,m,&err)) {
 	slog(st,LOG_SEC,"msg3: %s",err);
 	return False;
     }
-    uint32_t capab_adv_late = m.remote_capabilities
+    uint32_t capab_adv_late = m->remote_capabilities
 	& ~st->remote_capabilities & st->early_capabilities;
     if (capab_adv_late) {
 	slog(st,LOG_SEC,"msg3 impermissibly adds early capability flag(s)"
 	     " %#"PRIx32" (was %#"PRIx32", now %#"PRIx32")",
-	     capab_adv_late, st->remote_capabilities, m.remote_capabilities);
+	     capab_adv_late, st->remote_capabilities, m->remote_capabilities);
 	return False;
     }
 
@@ -921,11 +943,11 @@ static bool_t process_msg3(struct site *st, struct buffer_if *msg3,
     int i;								\
     for (i=0; i<st->n##kind##s; i++) {					\
 	iface=st->kind##s[i];						\
-	if (iface->capab_bit == m.capab_##kind##num)			\
+	if (iface->capab_bit == m->capab_##kind##num)			\
 	    goto kind##_found;						\
     }									\
     slog(st,LOG_SEC,"peer chose unknown-to-us " what " %d!",		\
-	 m.capab_##kind##num);							\
+	 m->capab_##kind##num);							\
     return False;							\
 kind##_found:								\
     st->chosen_##kind=iface;						\
@@ -935,7 +957,7 @@ kind##_found:								\
 
 #undef CHOSE_CRYPTO
 
-    if (!process_msg3_msg4(st,&m))
+    if (!process_msg3_msg4(st,m))
 	return False;
 
     /* Update our idea of the remote site's capabilities, now that we've
@@ -946,46 +968,46 @@ kind##_found:								\
      * doesn't change any of the bits we relied upon in the past, but it may
      * also have set additional capability bits.  We simply throw those away
      * now, and use the authentic capabilities from this MSG3. */
-    st->remote_capabilities=m.remote_capabilities;
+    st->remote_capabilities=m->remote_capabilities;
 
     /* Terminate their DH public key with a '0' */
-    m.pk[m.pklen]=0;
+    m->pk[m->pklen]=0;
     /* Invent our DH secret key */
     st->random->generate(st->random->st,st->dh->len,st->dhsecret);
 
     /* Generate the shared key and set up the transform */
-    if (!set_new_transform(st,m.pk)) return False;
+    if (!set_new_transform(st,m->pk)) return False;
 
     return True;
 }
 
-static bool_t generate_msg4(struct site *st)
+static bool_t generate_msg4(struct site *st, const struct msg *prompt)
 {
     /* We have both nonces, their public key and our private key. Generate
        our public key, sign it and send it to them. */
-    return generate_msg(st,LABEL_MSG4,"site:MSG4");
+    return generate_msg(st,LABEL_MSG4,"site:MSG4",prompt);
 }
 
 static bool_t process_msg4(struct site *st, struct buffer_if *msg4,
-			   const struct comm_addr *src)
+			   const struct comm_addr *src,
+			   struct msg *m /* returned */)
 {
-    struct msg m;
     cstring_t err;
 
-    if (!unpick_msg(st,LABEL_MSG4,msg4,&m)) return False;
-    if (!check_msg(st,LABEL_MSG4,&m,&err)) {
+    if (!unpick_msg(st,LABEL_MSG4,msg4,m)) return False;
+    if (!check_msg(st,LABEL_MSG4,m,&err)) {
 	slog(st,LOG_SEC,"msg4: %s",err);
 	return False;
     }
     
-    if (!process_msg3_msg4(st,&m))
+    if (!process_msg3_msg4(st,m))
 	return False;
 
     /* Terminate their DH public key with a '0' */
-    m.pk[m.pklen]=0;
+    m->pk[m->pklen]=0;
 
     /* Generate the shared key and set up the transform */
-    if (!set_new_transform(st,m.pk)) return False;
+    if (!set_new_transform(st,m->pk)) return False;
 
     return True;
 }
@@ -1009,7 +1031,7 @@ static bool_t unpick_msg0(struct site *st, struct buffer_if *msg0,
     /* Leaves transformed part of buffer untouched */
 }
 
-static bool_t generate_msg5(struct site *st)
+static bool_t generate_msg5(struct site *st, const struct msg *prompt)
 {
     cstring_t transform_err;
 
@@ -1075,7 +1097,7 @@ static void create_msg6(struct site *st, struct transform_inst_if *transform,
     buf_prepend_uint32(&st->buffer,session_id);
 }
 
-static bool_t generate_msg6(struct site *st)
+static bool_t generate_msg6(struct site *st, const struct msg *prompt)
 {
     if (!is_transform_valid(st->new_transform))
 	return False;
@@ -1352,7 +1374,7 @@ static void decrement_resolving_count(struct site *st, int by)
     switch (st->state) {
     case SITE_RESOLVE:
         if (transport_compute_setupinit_peers(st,addrs,naddrs,0)) {
-	    enter_new_state(st,SITE_SENTMSG1);
+	    enter_new_state(st,SITE_SENTMSG1,0);
 	} else {
 	    /* Can't figure out who to try to to talk to */
 	    slog(st,LOG_SETUP_INIT,
@@ -1412,7 +1434,7 @@ static bool_t initiate_key_setup(struct site *st, cstring_t reason,
 	slog(st,LOG_SETUP_INIT,"resolving peer address(es)");
 	return enter_state_resolve(st);
     } else if (transport_compute_setupinit_peers(st,0,0,prod_hint)) {
-	return enter_new_state(st,SITE_SENTMSG1);
+	return enter_new_state(st,SITE_SENTMSG1,0);
     }
     slog(st,LOG_SETUP_INIT,"key exchange failed: no address for peer");
     return False;
@@ -1566,21 +1588,25 @@ static bool_t enter_state_resolve(struct site *st)
     return ensure_resolving(st);
 }
 
-static bool_t enter_new_state(struct site *st, uint32_t next)
+static bool_t enter_new_state(struct site *st, uint32_t next,
+			      const struct msg *prompt
+			      /* may be 0 for SENTMSG1 */)
 {
-    bool_t (*gen)(struct site *st);
+    bool_t (*gen)(struct site *st, const struct msg *prompt);
     int r;
 
     slog(st,LOG_STATE,"entering state %s",state_name(next));
     switch(next) {
     case SITE_SENTMSG1:
 	state_assert(st,st->state==SITE_RUN || st->state==SITE_RESOLVE);
+	if (!kex_init(st)) return False;
 	gen=generate_msg1;
 	st->msg1_crossed_logged = False;
 	break;
     case SITE_SENTMSG2:
 	state_assert(st,st->state==SITE_RUN || st->state==SITE_RESOLVE ||
 		     st->state==SITE_SENTMSG1 || st->state==SITE_WAIT);
+	if (!kex_init(st)) return False;
 	gen=generate_msg2;
 	break;
     case SITE_SENTMSG3:
@@ -1611,7 +1637,7 @@ static bool_t enter_new_state(struct site *st, uint32_t next)
 
     if (hacky_par_start_failnow()) return False;
 
-    r= gen(st) && send_msg(st);
+    r= gen(st,prompt) && send_msg(st);
 
     hacky_par_end(&r,
 		  st->setup_retries, st->setup_retry_interval,
@@ -1795,15 +1821,31 @@ static void site_outgoing(void *sst, struct buffer_if *buf)
 }
 
 static bool_t named_for_us(struct site *st, const struct buffer_if *buf_in,
-			   uint32_t type, struct msg *m)
+			   uint32_t type, struct msg *m,
+			   struct priomsg *whynot)
     /* For packets which are identified by the local and remote names.
      * If it has our name and our peer's name in it it's for us. */
 {
     struct buffer_if buf[1];
     buffer_readonly_clone(buf,buf_in);
-    return unpick_msg(st,type,buf,m)
-	&& name_matches(&m->remote,st->remotename)
-	&& name_matches(&m->local,st->localname);
+
+    if (!unpick_msg(st,type,buf,m)) {
+	priomsg_update_fixed(whynot, comm_notify_whynot_unpick, "malformed");
+	return False;
+    }
+#define NAME_MATCHES(lr)						\
+    if (!name_matches(&m->lr, st->lr##name)) {				\
+	if (priomsg_update_fixed(whynot, comm_notify_whynot_name_##lr,	\
+                                 "unknown " #lr " name: ")) {		\
+            truncmsg_add_packet_string(&whynot->m, m->lr.len, m->lr.name); \
+        }								\
+        return False;							\
+    }
+    NAME_MATCHES(remote);
+    NAME_MATCHES(local );
+#undef NAME_MATCHES
+
+    return True;
 }
 
 static bool_t we_have_priority(struct site *st, const struct msg *m) {
@@ -1818,17 +1860,17 @@ static bool_t we_have_priority(struct site *st, const struct msg *m) {
 static bool_t setup_late_msg_ok(struct site *st, 
 				const struct buffer_if *buf_in,
 				uint32_t msgtype,
-				const struct comm_addr *source) {
+				const struct comm_addr *source,
+				struct msg *m /* returned */) {
     /* For setup packets which seem from their type like they are
      * late.  Maybe they came via a different path.  All we do is make
      * a note of the sending address, iff they look like they are part
      * of the current key setup attempt. */
-    struct msg m;
-    if (!named_for_us(st,buf_in,msgtype,&m))
+    if (!named_for_us(st,buf_in,msgtype,m,0))
 	/* named_for_us calls unpick_msg which gets the nonces */
 	return False;
-    if (!consttime_memeq(m.nR,st->remoteN,NONCELEN) ||
-	!consttime_memeq(m.nL,st->localN, NONCELEN))
+    if (!consttime_memeq(m->nR,st->remoteN,NONCELEN) ||
+	!consttime_memeq(m->nL,st->localN, NONCELEN))
 	/* spoof ?  from stale run ?  who knows */
 	return False;
     transport_setup_msgok(st,source);
@@ -1841,7 +1883,8 @@ static bool_t setup_late_msg_ok(struct site *st,
    this current site instance (and should therefore not be processed
    by other sites), even if the packet was otherwise ignored. */
 static bool_t site_incoming(void *sst, struct buffer_if *buf,
-			    const struct comm_addr *source)
+			    const struct comm_addr *source,
+			    struct priomsg *whynot)
 {
     struct site *st=sst;
 
@@ -1849,10 +1892,11 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf,
 
     uint32_t dest=get_uint32(buf->start);
     uint32_t msgtype=get_uint32(buf->start+8);
-    struct msg named_msg;
+    struct msg msg;
+      /* initialised by named_for_us, or process_msgN for N!=1 */
 
     if (msgtype==LABEL_MSG1) {
-	if (!named_for_us(st,buf,msgtype,&named_msg))
+	if (!named_for_us(st,buf,msgtype,&msg,whynot))
 	    return False;
 	/* It's a MSG1 addressed to us. Decide what to do about it. */
 	dump_packet(st,buf,source,True,True);
@@ -1860,9 +1904,9 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf,
 	    st->state==SITE_WAIT) {
 	    /* We should definitely process it */
 	    transport_compute_setupinit_peers(st,0,0,source);
-	    if (process_msg1(st,buf,source,&named_msg)) {
+	    if (process_msg1(st,buf,source,&msg)) {
 		slog(st,LOG_SETUP_INIT,"key setup initiated by peer");
-		bool_t entered=enter_new_state(st,SITE_SENTMSG2);
+		bool_t entered=enter_new_state(st,SITE_SENTMSG2,&msg);
 		if (entered && st->addresses && st->local_mobile)
 		    /* We must do this as the very last thing, because
 		       the resolver callback might reenter us. */
@@ -1876,7 +1920,7 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf,
 	    /* We've just sent a message 1! They may have crossed on
 	       the wire. If we have priority then we ignore the
 	       incoming one, otherwise we process it as usual. */
-	    if (we_have_priority(st,&named_msg)) {
+	    if (we_have_priority(st,&msg)) {
 		BUF_FREE(buf);
 		if (!st->msg1_crossed_logged++)
 		    slog(st,LOG_SETUP_INIT,"crossed msg1s; we are higher "
@@ -1885,10 +1929,10 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf,
 	    } else {
 		slog(st,LOG_SETUP_INIT,"crossed msg1s; we are lower "
 		     "priority => use incoming msg1");
-		if (process_msg1(st,buf,source,&named_msg)) {
+		if (process_msg1(st,buf,source,&msg)) {
 		    BUF_FREE(&st->buffer); /* Free our old message 1 */
 		    transport_setup_msgok(st,source);
-		    enter_new_state(st,SITE_SENTMSG2);
+		    enter_new_state(st,SITE_SENTMSG2,&msg);
 		} else {
 		    slog(st,LOG_ERROR,"failed to process an incoming "
 			 "crossed msg1 (we have low priority)");
@@ -1898,7 +1942,7 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf,
 	    }
 	} else if (st->state==SITE_SENTMSG2 ||
 		   st->state==SITE_SENTMSG4) {
-	    if (consttime_memeq(named_msg.nR,st->remoteN,NONCELEN)) {
+	    if (consttime_memeq(msg.nR,st->remoteN,NONCELEN)) {
 		/* We are ahead in the protocol, but that msg1 had the
 		 * peer's nonce so presumably it is from this key
 		 * exchange run, via a slower route */
@@ -1916,7 +1960,7 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf,
 	return True;
     }
     if (msgtype==LABEL_PROD) {
-	if (!named_for_us(st,buf,msgtype,&named_msg))
+	if (!named_for_us(st,buf,msgtype,&msg,whynot))
 	    return False;
 	dump_packet(st,buf,source,True,True);
 	if (st->state!=SITE_RUN) {
@@ -1957,12 +2001,12 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf,
 	    if (st->state!=SITE_SENTMSG1) {
 		if ((st->state==SITE_SENTMSG3 ||
 		     st->state==SITE_SENTMSG5) &&
-		    setup_late_msg_ok(st,buf,msgtype,source))
+		    setup_late_msg_ok(st,buf,msgtype,source,&msg))
 		    break;
 		slog(st,LOG_UNEXPECTED,"unexpected MSG2");
-	    } else if (process_msg2(st,buf,source)) {
+	    } else if (process_msg2(st,buf,source,&msg)) {
 		transport_setup_msgok(st,source);
-		enter_new_state(st,SITE_SENTMSG3);
+		enter_new_state(st,SITE_SENTMSG3,&msg);
 	    } else {
 		slog(st,LOG_SEC,"invalid MSG2");
 	    }
@@ -1971,12 +2015,12 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf,
 	    /* Setup packet: expected only in state SENTMSG2 */
 	    if (st->state!=SITE_SENTMSG2) {
 		if ((st->state==SITE_SENTMSG4) &&
-		    setup_late_msg_ok(st,buf,msgtype,source))
+		    setup_late_msg_ok(st,buf,msgtype,source,&msg))
 		    break;
 		slog(st,LOG_UNEXPECTED,"unexpected MSG3");
-	    } else if (process_msg3(st,buf,source,msgtype)) {
+	    } else if (process_msg3(st,buf,source,msgtype,&msg)) {
 		transport_setup_msgok(st,source);
-		enter_new_state(st,SITE_SENTMSG4);
+		enter_new_state(st,SITE_SENTMSG4,&msg);
 	    } else {
 		slog(st,LOG_SEC,"invalid MSG3");
 	    }
@@ -1985,12 +2029,12 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf,
 	    /* Setup packet: expected only in state SENTMSG3 */
 	    if (st->state!=SITE_SENTMSG3) {
 		if ((st->state==SITE_SENTMSG5) &&
-		    setup_late_msg_ok(st,buf,msgtype,source))
+		    setup_late_msg_ok(st,buf,msgtype,source,&msg))
 		    break;
 		slog(st,LOG_UNEXPECTED,"unexpected MSG4");
-	    } else if (process_msg4(st,buf,source)) {
+	    } else if (process_msg4(st,buf,source,&msg)) {
 		transport_setup_msgok(st,source);
-		enter_new_state(st,SITE_SENTMSG5);
+		enter_new_state(st,SITE_SENTMSG5,&msg);
 	    } else {
 		slog(st,LOG_SEC,"invalid MSG4");
 	    }
@@ -2005,7 +2049,7 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf,
 	    if (st->state==SITE_SENTMSG4) {
 		if (process_msg5(st,buf,source,st->new_transform)) {
 		    transport_setup_msgok(st,source);
-		    enter_new_state(st,SITE_RUN);
+		    enter_new_state(st,SITE_RUN,&msg);
 		} else {
 		    slog(st,LOG_SEC,"invalid MSG5");
 		}
@@ -2045,6 +2089,8 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf,
 	return True;
     }
 
+    priomsg_update_fixed(whynot, comm_notify_whynot_general,
+			 "not MSG1 or PROD; unknown dest index");
     return False;
 }