Fix a potential NULL-pointer dereference when generating invitations.

[meshlink] / src / protocol_key.c

diff --git a/src/protocol_key.c b/src/protocol_key.c
index 6384eb3979d9d92154e963913a4763693f13dd1b..cae95047220341def5d777f2e01f58ed309d6c53 100644 (file)
--- a/src/protocol_key.c
+++ b/src/protocol_key.c
@@ -1,6 +1,6 @@
 /*
     protocol_key.c -- handle the meta-protocol, key exchange
-    Copyright (C) 2014 Guus Sliepen <guus@meshlink.io>
+    Copyright (C) 2014-2017 Guus Sliepen <guus@meshlink.io>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -37,8 +37,9 @@ void send_key_changed(meshlink_handle_t *mesh) {
        /* Force key exchange for connections using SPTPS */
 
        for splay_each(node_t, n, mesh->nodes)
-               if(n->status.reachable && n->status.validkey)
+               if(n->status.reachable && n->status.validkey) {
                        sptps_force_kex(&n->sptps);
+               }
 }
 
 bool key_changed_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
@@ -50,8 +51,9 @@ bool key_changed_h(meshlink_handle_t *mesh, connection_t *c, const char *request
                return false;
        }
 
-       if(seen_request(mesh, request))
+       if(seen_request(mesh, request)) {
                return true;
+       }
 
        n = lookup_node(mesh, name);
 
@@ -68,6 +70,7 @@ bool key_changed_h(meshlink_handle_t *mesh, connection_t *c, const char *request
 }
 
 static bool send_initial_sptps_data(void *handle, uint8_t type, const void *data, size_t len) {
+       (void)type;
        node_t *to = handle;
        meshlink_handle_t *mesh = to->mesh;
        to->sptps.send_data = send_sptps_data;
@@ -83,8 +86,9 @@ bool send_req_key(meshlink_handle_t *mesh, node_t *to) {
                return true;
        }
 
-       if(to->sptps.label)
+       if(to->sptps.label) {
                logger(mesh, MESHLINK_DEBUG, "send_req_key(%s) called while sptps->label != NULL!", to->name);
+       }
 
        char label[sizeof(meshlink_udp_label) + strlen(mesh->self->name) + strlen(to->name) + 2];
        snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, mesh->self->name, to->name);
@@ -99,6 +103,8 @@ bool send_req_key(meshlink_handle_t *mesh, node_t *to) {
 /* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
 
 static bool req_key_ext_h(meshlink_handle_t *mesh, connection_t *c, const char *request, node_t *from, int reqno) {
+       (void)c;
+
        switch(reqno) {
        case REQ_PUBKEY: {
                char *pubkey = ecdsa_get_base64_public_key(mesh->self->connection->ecdsa);
@@ -114,6 +120,7 @@ static bool req_key_ext_h(meshlink_handle_t *mesh, connection_t *c, const char *
                }
 
                char pubkey[MAX_STRING_SIZE];
+
                if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(pubkey))) {
                        logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_PUBKEY", from->name, "invalid pubkey");
                        return true;
@@ -133,6 +140,7 @@ static bool req_key_ext_h(meshlink_handle_t *mesh, connection_t *c, const char *
 
                if(from->sptps.label) {
                        logger(mesh, MESHLINK_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
+
                        if(strcmp(mesh->self->name, from->name) < 0) {
                                logger(mesh, MESHLINK_DEBUG, "Ignoring REQ_KEY from %s.", from->name);
                                return true;
@@ -166,10 +174,12 @@ static bool req_key_ext_h(meshlink_handle_t *mesh, connection_t *c, const char *
 
                char buf[MAX_STRING_SIZE];
                int len;
+
                if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
                        logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS", from->name, "invalid SPTPS data");
                        return true;
                }
+
                sptps_receive_data(&from->sptps, buf, len);
                return true;
        }
@@ -216,11 +226,12 @@ bool req_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
 
        if(to == mesh->self) {                      /* Yes */
                /* Is this an extended REQ_KEY message? */
-               if(reqno)
+               if(reqno) {
                        return req_key_ext_h(mesh, c, request, from, reqno);
+               }
 
-               /* No, just send our key back */
-               send_ans_key(mesh, from);
+               /* This should never happen. Ignore it, unless it came directly from the connected peer, in which case we disconnect. */
+               return from->connection != c;
        } else {
                if(!to->status.reachable) {
                        logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
@@ -235,6 +246,8 @@ bool req_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
 }
 
 bool send_ans_key(meshlink_handle_t *mesh, node_t *to) {
+       (void)mesh;
+       (void)to;
        abort();
 }
 
@@ -313,8 +326,9 @@ bool ans_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
        char buf[strlen(key)];
        int len = b64decode(key, buf, strlen(key));
 
-       if(!len || !sptps_receive_data(&from->sptps, buf, len))
+       if(!len || !sptps_receive_data(&from->sptps, buf, len)) {
                logger(mesh, MESHLINK_ERROR, "Error processing SPTPS data from %s", from->name);
+       }
 
        if(from->status.validkey) {
                if(*address && *port) {
@@ -323,8 +337,9 @@ bool ans_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
                        update_node_udp(mesh, from, &sa);
                }
 
-               if(from->options & OPTION_PMTU_DISCOVERY && !(from->options & OPTION_TCPONLY))
+               if(from->options & OPTION_PMTU_DISCOVERY && !(from->options & OPTION_TCPONLY)) {
                        send_mtu_probe(mesh, from);
+               }
        }
 
        return true;