httpcaddyfile: Detect ambiguous site definitions (fix #4635)

Previously, our "duplicate key in server block" logic was flawed because
it did not account for the site's bind address. We defer this check to
when the listener addresses have been assigned, but before we commit
a server block to its listener.

Also refined how network address parsing and joining works, which was
necessary for a less convoluted fix.

1 files changed, 9 insertions, 5 deletions

diff --git a/caddyconfig/httpcaddyfile/addresses.go b/caddyconfig/httpcaddyfile/addresses.go
index c7923e8..03083d8 100644
--- a/caddyconfig/httpcaddyfile/addresses.go
+++ b/caddyconfig/httpcaddyfile/addresses.go
@@ -183,6 +183,8 @@ func (st *ServerType) consolidateAddrMappings(addrToServerBlocks map[string][]se
 	return sbaddrs
 }
 
+// listenerAddrsForServerBlockKey essentially converts the Caddyfile
+// site addresses to Caddy listener addresses for each server block.
 func (st *ServerType) listenerAddrsForServerBlockKey(sblock serverBlock, key string,
 	options map[string]interface{}) ([]string, error) {
 	addr, err := ParseAddress(key)
@@ -232,12 +234,14 @@ func (st *ServerType) listenerAddrsForServerBlockKey(sblock serverBlock, key str
 	// use a map to prevent duplication
 	listeners := make(map[string]struct{})
 	for _, host := range lnHosts {
-		addr, err := caddy.ParseNetworkAddress(host)
-		if err == nil && addr.IsUnixNetwork() {
-			listeners[host] = struct{}{}
-		} else {
-			listeners[host+":"+lnPort] = struct{}{}
+		// host can have network + host (e.g. "tcp6/localhost") but
+		// will/should not have port information because this usually
+		// comes from the bind directive, so we append the port
+		addr, err := caddy.ParseNetworkAddress(host + ":" + lnPort)
+		if err != nil {
+			return nil, fmt.Errorf("parsing network address: %v", err)
 		}
+		listeners[addr.String()] = struct{}{}
 	}
 
 	// now turn map into list