X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=site.c;h=2e8335ae634bb297035f2761f0ec6a4ecb06810e;hb=1737eeef9bc4aec1b4d7baa220ce48238b498006;hp=b9b4d0dd0c0974e3b5d960a077977e14c54d9349;hpb=5ad34db2ccbbfbc936cd16121bed2110b70594ba;p=secnet.git

diff --git a/site.c b/site.c
index b9b4d0d..2e8335a 100644
--- a/site.c
+++ b/site.c
@@ -288,6 +288,7 @@ struct site {
     uint64_t timeout; /* Timeout for current state */
     uint8_t *dhsecret;
     uint8_t *sharedsecret;
+    uint32_t sharedsecretlen;
     struct transform_inst_if *new_transform; /* For key setup/verify */
 };
 
@@ -346,14 +347,19 @@ static bool_t current_valid(struct site *st)
     type=buf_unprepend_uint32((b)); \
     if (type!=(t)) return False; } while(0)
 
+struct parsedname {
+    int32_t len;
+    uint8_t *name;
+    int32_t extrainfo_len;
+    uint8_t *extrainfo;
+};
+
 struct msg {
     uint8_t *hashstart;
     uint32_t dest;
     uint32_t source;
-    int32_t remlen;
-    uint8_t *remote;
-    int32_t loclen;
-    uint8_t *local;
+    struct parsedname remote;
+    struct parsedname local;
     uint8_t *nR;
     uint8_t *nL;
     int32_t pklen;
@@ -401,6 +407,24 @@ static bool_t generate_msg(struct site *st, uint32_t type, cstring_t what)
     return True;
 }
 
+static bool_t unpick_name(struct buffer_if *msg, struct parsedname *nm)
+{
+    CHECK_AVAIL(msg,2);
+    nm->len=buf_unprepend_uint16(msg);
+    CHECK_AVAIL(msg,nm->len);
+    nm->name=buf_unprepend(msg,nm->len);
+    uint8_t *nul=memchr(nm->name,0,nm->len);
+    if (!nul) {
+	nm->extrainfo_len=0;
+	nm->extrainfo=0;
+    } else {
+	nm->extrainfo=nul+1;
+	nm->extrainfo_len=msg->start-nm->extrainfo;
+	nm->len=nul-nm->name;
+    }
+    return True;
+}
+
 static bool_t unpick_msg(struct site *st, uint32_t type,
 			 struct buffer_if *msg, struct msg *m)
 {
@@ -410,14 +434,8 @@ static bool_t unpick_msg(struct site *st, uint32_t type,
     CHECK_AVAIL(msg,4);
     m->source=buf_unprepend_uint32(msg);
     CHECK_TYPE(msg,type);
-    CHECK_AVAIL(msg,2);
-    m->remlen=buf_unprepend_uint16(msg);
-    CHECK_AVAIL(msg,m->remlen);
-    m->remote=buf_unprepend(msg,m->remlen);
-    CHECK_AVAIL(msg,2);
-    m->loclen=buf_unprepend_uint16(msg);
-    CHECK_AVAIL(msg,m->loclen);
-    m->local=buf_unprepend(msg,m->loclen);
+    if (!unpick_name(msg,&m->remote)) return False;
+    if (!unpick_name(msg,&m->local)) return False;
     CHECK_AVAIL(msg,NONCELEN);
     m->nR=buf_unprepend(msg,NONCELEN);
     if (type==LABEL_MSG1) {
@@ -443,6 +461,14 @@ static bool_t unpick_msg(struct site *st, uint32_t type,
     return True;
 }
 
+static bool_t name_matches(const struct parsedname *nm, const char *expected)
+{
+    int expected_len=strlen(expected);
+    return
+	nm->len == expected_len &&
+	!memcmp(nm->name, expected, expected_len);
+}    
+
 static bool_t check_msg(struct site *st, uint32_t type, struct msg *m,
 			cstring_t *error)
 {
@@ -450,11 +476,11 @@ static bool_t check_msg(struct site *st, uint32_t type, struct msg *m,
 
     /* Check that the site names and our nonce have been sent
        back correctly, and then store our peer's nonce. */ 
-    if (memcmp(m->remote,st->remotename,strlen(st->remotename)!=0)) {
+    if (!name_matches(&m->remote,st->remotename)) {
 	*error="wrong remote site name";
 	return False;
     }
-    if (memcmp(m->local,st->localname,strlen(st->localname)!=0)) {
+    if (!name_matches(&m->local,st->localname)) {
 	*error="wrong local site name";
 	return False;
     }
@@ -561,11 +587,11 @@ static bool_t process_msg3(struct site *st, struct buffer_if *msg3,
 
     /* Generate the shared key */
     st->dh->makeshared(st->dh->st,st->dhsecret,st->dh->len,m.pk,
-		       st->sharedsecret,st->transform->keylen);
+		       st->sharedsecret,st->sharedsecretlen);
 
     /* Set up the transform */
     st->new_transform->setkey(st->new_transform->st,st->sharedsecret,
-			      st->transform->keylen);
+			      st->sharedsecretlen,st->setup_priority);
 
     return True;
 }
@@ -609,10 +635,10 @@ static bool_t process_msg4(struct site *st, struct buffer_if *msg4,
     m.pk[m.pklen]=0;
     /* Generate the shared key */
     st->dh->makeshared(st->dh->st,st->dhsecret,st->dh->len,m.pk,
-		       st->sharedsecret,st->transform->keylen);
+		       st->sharedsecret,st->sharedsecretlen);
     /* Set up the transform */
     st->new_transform->setkey(st->new_transform->st,st->sharedsecret,
-			      st->transform->keylen);
+			      st->sharedsecretlen,st->setup_priority);
 
     return True;
 }
@@ -730,7 +756,8 @@ static bool_t process_msg6(struct site *st, struct buffer_if *msg6,
     return True;
 }
 
-static bool_t decrypt_msg0(struct site *st, struct buffer_if *msg0)
+static bool_t decrypt_msg0(struct site *st, struct buffer_if *msg0,
+			   const struct comm_addr *src)
 {
     cstring_t transform_err, auxkey_err, newkey_err="n/a";
     struct msg0 m;
@@ -749,11 +776,8 @@ static bool_t decrypt_msg0(struct site *st, struct buffer_if *msg0)
 			   "peer has used new key","auxiliary key",LOG_SEC);
 	return True;
     }
-
-    if (problem==2) {
-	slog(st,LOG_DROP,"transform: %s (merely skew)",transform_err);
-	return False;
-    }
+    if (problem==2)
+	goto skew;
 
     buffer_copy(msg0, &st->scratch);
     problem = st->auxiliary_key.transform->reverse
@@ -777,11 +801,14 @@ static bool_t decrypt_msg0(struct site *st, struct buffer_if *msg0)
 	}
 	return True;
     }
+    if (problem==2)
+	goto skew;
 
     if (st->state==SITE_SENTMSG5) {
 	buffer_copy(msg0, &st->scratch);
-	if (!st->new_transform->reverse(st->new_transform->st,
-					msg0,&newkey_err)) {
+	problem = st->new_transform->reverse(st->new_transform->st,
+					     msg0,&newkey_err);
+	if (!problem) {
 	    /* It looks like we didn't get the peer's MSG6 */
 	    /* This is like a cut-down enter_new_state(SITE_RUN) */
 	    slog(st,LOG_STATE,"will enter state RUN (MSG0 with new key)");
@@ -790,11 +817,18 @@ static bool_t decrypt_msg0(struct site *st, struct buffer_if *msg0)
 	    activate_new_key(st);
 	    return True; /* do process the data in this packet */
 	}
+	if (problem==2)
+	    goto skew;
     }
 
     slog(st,LOG_SEC,"transform: %s (aux: %s, new: %s)",
 	 transform_err,auxkey_err,newkey_err);
     initiate_key_setup(st,"incoming message would not decrypt");
+    send_nak(src,m.dest,m.source,m.type,msg0,"message would not decrypt");
+    return False;
+
+ skew:
+    slog(st,LOG_DROP,"transform: %s (merely skew)",transform_err);
     return False;
 }
 
@@ -803,7 +837,7 @@ static bool_t process_msg0(struct site *st, struct buffer_if *msg0,
 {
     uint32_t type;
 
-    if (!decrypt_msg0(st,msg0))
+    if (!decrypt_msg0(st,msg0,src))
 	return False;
 
     CHECK_AVAIL(msg0,4);
@@ -1009,7 +1043,7 @@ static void enter_state_run(struct site *st)
     memset(st->remoteN,0,NONCELEN);
     st->new_transform->delkey(st->new_transform->st);
     memset(st->dhsecret,0,st->dh->len);
-    memset(st->sharedsecret,0,st->transform->keylen);
+    memset(st->sharedsecret,0,st->sharedsecretlen);
     set_link_quality(st);
 }
 
@@ -1285,7 +1319,7 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf,
 	uint32_t msgtype=ntohl(get_uint32(buf->start+8));
 	if (msgtype!=LABEL_MSG0) dump_packet(st,buf,source,True);
 	switch (msgtype) {
-	case 0: /* NAK */
+	case LABEL_NAK:
 	    /* If the source is our current peer then initiate a key setup,
 	       because our peer's forgotten the key */
 	    if (get_uint32(buf->start+4)==st->current.remote_session_id) {
@@ -1557,7 +1591,8 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context,
     transport_peers_clear(st,&st->setup_peers);
     /* XXX mlock these */
     st->dhsecret=safe_malloc(st->dh->len,"site:dhsecret");
-    st->sharedsecret=safe_malloc(st->transform->keylen,"site:sharedsecret");
+    st->sharedsecretlen=st->transform->keylen?:st->dh->ceil_len;
+    st->sharedsecret=safe_malloc(st->sharedsecretlen,"site:sharedsecret");
 
     /* We need to compute some properties of our comms */
 #define COMPUTE_WORST(pad)			\