Prevent oracle attacks in the legacy protocol (CVE-2018-16737, CVE-2018-16738)

[tinc] / src / protocol.c

diff --git a/src/protocol.c b/src/protocol.c
index efb9a18..c7dd8fb 100644 (file)
--- a/src/protocol.c
+++ b/src/protocol.c
@@ -35,25 +35,26 @@ bool experimental = true;
 /* Jumptable for the request handlers */
 
 static bool (*request_handlers[])(connection_t *, const char *) = {
-               id_h, metakey_h, challenge_h, chal_reply_h, ack_h,
-               status_h, error_h, termreq_h,
-               ping_h, pong_h,
-               add_subnet_h, del_subnet_h,
-               add_edge_h, del_edge_h,
-               key_changed_h, req_key_h, ans_key_h, tcppacket_h, control_h,
-               NULL, NULL, NULL, /* Not "real" requests (yet) */
-               udp_info_h, mtu_info_h,
+       id_h, metakey_h, challenge_h, chal_reply_h, ack_h,
+       NULL, NULL, termreq_h,
+       ping_h, pong_h,
+       add_subnet_h, del_subnet_h,
+       add_edge_h, del_edge_h,
+       key_changed_h, req_key_h, ans_key_h, tcppacket_h, control_h,
+       NULL, NULL, /* Not "real" requests (yet) */
+       sptps_tcppacket_h,
+       udp_info_h, mtu_info_h,
 };
 
 /* Request names */
 
 static char (*request_name[]) = {
-               "ID", "METAKEY", "CHALLENGE", "CHAL_REPLY", "ACK",
-               "STATUS", "ERROR", "TERMREQ",
-               "PING", "PONG",
-               "ADD_SUBNET", "DEL_SUBNET",
-               "ADD_EDGE", "DEL_EDGE", "KEY_CHANGED", "REQ_KEY", "ANS_KEY", "PACKET", "CONTROL",
-               "REQ_PUBKEY", "ANS_PUBKEY", "REQ_SPTPS", "UDP_INFO", "MTU_INFO",
+       "ID", "METAKEY", "CHALLENGE", "CHAL_REPLY", "ACK",
+       "STATUS", "ERROR", "TERMREQ",
+       "PING", "PONG",
+       "ADD_SUBNET", "DEL_SUBNET",
+       "ADD_EDGE", "DEL_EDGE", "KEY_CHANGED", "REQ_KEY", "ANS_KEY", "PACKET", "CONTROL",
+       "REQ_PUBKEY", "ANS_PUBKEY", "SPTPS_PACKET", "UDP_INFO", "MTU_INFO",
 };
 
 static splay_tree_t *past_request_tree;
@@ -71,24 +72,32 @@ bool send_request(connection_t *c, const char *format, ...) {
           input buffer anyway */
 
        va_start(args, format);
-       len = vsnprintf(request, MAXBUFSIZE, format, args);
+       len = vsnprintf(request, sizeof(request), format, args);
+       request[sizeof(request) - 1] = 0;
        va_end(args);
 
-       if(len < 0 || len > MAXBUFSIZE - 1) {
+       if(len < 0 || len > sizeof(request) - 1) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Output buffer overflow while sending request to %s (%s)",
-                          c->name, c->hostname);
+                      c->name, c->hostname);
                return false;
        }
 
-       logger(DEBUG_META, LOG_DEBUG, "Sending %s to %s (%s): %s", request_name[atoi(request)], c->name, c->hostname, request);
+       int id = atoi(request);
+       logger(DEBUG_META, LOG_DEBUG, "Sending %s to %s (%s): %s", request_name[id], c->name, c->hostname, request);
 
        request[len++] = '\n';
 
        if(c == everyone) {
                broadcast_meta(NULL, request, len);
                return true;
-       } else
-               return send_meta(c, request, len);
+       } else {
+               if(id) {
+                       return send_meta(c, request, len);
+               } else {
+                       send_meta_raw(c, request, len);
+                       return true;
+               }
+       }
 }
 
 void forward_request(connection_t *from, const char *request) {
@@ -99,13 +108,15 @@ void forward_request(connection_t *from, const char *request) {
        char tmp[len + 1];
        memcpy(tmp, request, len);
        tmp[len] = '\n';
-       broadcast_meta(from, tmp, sizeof tmp);
+       broadcast_meta(from, tmp, sizeof(tmp));
 }
 
 bool receive_request(connection_t *c, const char *request) {
        if(c->outgoing && proxytype == PROXY_HTTP && c->allow_request == ID) {
-               if(!request[0] || request[0] == '\r')
+               if(!request[0] || request[0] == '\r') {
                        return true;
+               }
+
                if(!strncasecmp(request, "HTTP/1.1 ", 9)) {
                        if(!strncmp(request + 9, "200", 3)) {
                                logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Proxy request granted");
@@ -135,8 +146,10 @@ bool receive_request(connection_t *c, const char *request) {
                if(!request_handlers[reqno](c, request)) {
                        /* Something went wrong. Probably scriptkiddies. Terminate. */
 
-                       if(reqno != TERMREQ)
+                       if(reqno != TERMREQ) {
                                logger(DEBUG_ALWAYS, LOG_ERR, "Error while processing %s from %s (%s)", request_name[reqno], c->name, c->hostname);
+                       }
+
                        return false;
                }
        } else {
@@ -152,8 +165,9 @@ static int past_request_compare(const past_request_t *a, const past_request_t *b
 }
 
 static void free_past_request(past_request_t *r) {
-       if(r->request)
+       if(r->request) {
                free((char *)r->request);
+       }
 
        free(r);
 }
@@ -164,17 +178,21 @@ static void age_past_requests(void *data) {
        int left = 0, deleted = 0;
 
        for splay_each(past_request_t, p, past_request_tree) {
-               if(p->firstseen + pinginterval <= now.tv_sec)
+               if(p->firstseen + pinginterval <= now.tv_sec) {
                        splay_delete_node(past_request_tree, node), deleted++;
-               else
+               } else {
                        left++;
+               }
        }
 
-       if(left || deleted)
+       if(left || deleted) {
                logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Aging past requests: deleted %d, left %d", deleted, left);
+       }
 
        if(left)
-               timeout_set(&past_request_timeout, &(struct timeval){10, rand() % 100000});
+               timeout_set(&past_request_timeout, &(struct timeval) {
+               10, rand() % 100000
+       });
 }
 
 bool seen_request(const char *request) {
@@ -186,11 +204,13 @@ bool seen_request(const char *request) {
                logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Already seen request");
                return true;
        } else {
-               new = xmalloc(sizeof *new);
+               new = xmalloc(sizeof(*new));
                new->request = xstrdup(request);
                new->firstseen = now.tv_sec;
                splay_insert(past_request_tree, new);
-               timeout_add(&past_request_timeout, age_past_requests, NULL, &(struct timeval){10, rand() % 100000});
+               timeout_add(&past_request_timeout, age_past_requests, NULL, &(struct timeval) {
+                       10, rand() % 100000
+               });
                return false;
        }
 }