Fix high cpu usage with IPv6 recursor address. Closes #6120 (#6128)

hashicorp · Feb 18, 2020 · 3a2c865 · 3a2c865
1 parent 35a2c84
commit 3a2c865
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Showing 2 changed files with 25 additions and 3 deletions.
diff --git a/agent/dns.go b/agent/dns.go
@@ -274,9 +274,16 @@ func recursorAddr(recursor string) (string, error) {
 	// Add the port if none
 START:
 	_, _, err := net.SplitHostPort(recursor)
-	if ae, ok := err.(*net.AddrError); ok && ae.Err == "missing port in address" {
-		recursor = ipaddr.FormatAddressPort(recursor, 53)
-		goto START
+	if ae, ok := err.(*net.AddrError); ok {
+		if ae.Err == "missing port in address" {
+			recursor = ipaddr.FormatAddressPort(recursor, 53)
+			goto START
+		} else if ae.Err == "too many colons in address" {
+			if ip := net.ParseIP(recursor); ip != nil && ip.To4() == nil {
+				recursor = ipaddr.FormatAddressPort(recursor, 53)
+				goto START
+			}
+		}
 	}
 	if err != nil {
 		return "", err

diff --git a/agent/dns_test.go b/agent/dns_test.go
@@ -109,6 +109,21 @@ func TestRecursorAddr(t *testing.T) {
 	if addr != "8.8.8.8:53" {
 		t.Fatalf("bad: %v", addr)
 	}
+	addr, err = recursorAddr("2001:4860:4860::8888")
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if addr != "[2001:4860:4860::8888]:53" {
+		t.Fatalf("bad: %v", addr)
+	}
+	addr, err = recursorAddr("1.2.3.4::53")
+	if err == nil || !strings.Contains(err.Error(), "too many colons in address") {
+		t.Fatalf("err: %v", err)
+	}
+	addr, err = recursorAddr("2001:4860:4860::8888:::53")
+	if err == nil || !strings.Contains(err.Error(), "too many colons in address") {
+		t.Fatalf("err: %v", err)
+	}
 }
 
 func TestEncodeKVasRFC1464(t *testing.T) {