From 6552fbeafa3b48ef00562cfdc77596a243a06059 Mon Sep 17 00:00:00 2001
From: tedu <tedu@openbsd.org>
Date: Thu, 27 Apr 2017 16:09:32 +0000
Subject: [PATCH] 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.

---
 usr.sbin/rebound/rebound.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/usr.sbin/rebound/rebound.c b/usr.sbin/rebound/rebound.c
index a33029cd9bc..2f3bc9b6bb9 100644
--- 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)) {
-- 
2.20.1