clang warns about some of the strlcpy arguments here, which aren't the

typical idiom because there's invisible size dependencies. rewrite some
of it to use memcpy, which makes clear the lengths are the same.

diff --git a/usr.sbin/rebound/rebound.c b/usr.sbin/rebound/rebound.c
index a33029c..2f3bc9b 100644 (file)
--- a/usr.sbin/rebound/rebound.c
+++ b/usr.sbin/rebound/rebound.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: rebound.c,v 1.82 2017/04/13 15:32:15 tedu Exp $ */
+/* $OpenBSD: rebound.c,v 1.83 2017/04/27 16:09:32 tedu Exp $ */
 /*
  * Copyright (c) 2015 Ted Unangst <tedu@openbsd.org>
  *
@@ -196,11 +196,14 @@ cachelookup(struct dnspacket *dnsreq, size_t reqlen)
        struct dnscache *hit, key;
        unsigned char origname[NAMELEN];
        uint16_t origid;
+       size_t namelen;
 
        if (ntohs(dnsreq->qdcount) != 1)
                return NULL;
 
-       strlcpy(origname, dnsreq->qname, sizeof(origname));
+       namelen = strlcpy(origname, dnsreq->qname, sizeof(origname));
+       if (namelen >= sizeof(origname))
+               return NULL;
        lowercase(dnsreq->qname);
 
        origid = dnsreq->id;
@@ -212,7 +215,7 @@ cachelookup(struct dnspacket *dnsreq, size_t reqlen)
        if (hit)
                cachehits += 1;
 
-       strlcpy(dnsreq->qname, origname, sizeof(origname));
+       memcpy(dnsreq->qname, origname, namelen + 1);
        dnsreq->id = origid;
        return hit;
 }
@@ -287,7 +290,7 @@ newrequest(int ud, struct sockaddr *remoteaddr)
        conntotal += 1;
        if ((hit = cachelookup(dnsreq, r))) {
                hit->resp->id = dnsreq->id;
-               strlcpy(hit->resp->qname, dnsreq->qname, strlen(hit->resp->qname) + 1);
+               memcpy(hit->resp->qname, dnsreq->qname, strlen(hit->resp->qname) + 1);
                sendto(ud, hit->resp, hit->resplen, 0, &from.a, fromlen);
                return NULL;
        }
@@ -308,9 +311,12 @@ newrequest(int ud, struct sockaddr *remoteaddr)
        req->reqid = randomid();
        dnsreq->id = req->reqid;
        if (ntohs(dnsreq->qdcount) == 1) {
-               strlcpy(req->origname, dnsreq->qname, sizeof(req->origname));
+               size_t namelen;
+               namelen = strlcpy(req->origname, dnsreq->qname, sizeof(req->origname));
+               if (namelen >= sizeof(req->origname))
+                       goto fail;
                randomcase(dnsreq->qname);
-               strlcpy(req->newname, dnsreq->qname, sizeof(req->newname));
+               memcpy(req->newname, dnsreq->qname, namelen + 1);
 
                hit = calloc(1, sizeof(*hit));
                if (hit) {
@@ -418,7 +424,7 @@ sendreply(struct request *req)
                        return;
                if (strcmp(resp->qname, req->newname) != 0)
                        return;
-               strlcpy(resp->qname, req->origname, strlen(resp->qname) + 1);
+               memcpy(resp->qname, req->origname, strlen(resp->qname) + 1);
        }
        sendto(req->client, buf, r, 0, &req->from.a, req->fromlen);
        if ((ent = req->cacheent)) {