From dd0679ad45eebd357ef9e55cbbbedb33df49ea23 Mon Sep 17 00:00:00 2001
From: Miroslav Lichvar <mlichvar@redhat.com>
Date: Fri, 3 Jan 2020 09:36:59 +0100
Subject: [PATCH] socket: add function to check supported family

Don't log error when an IPv6 socket cannot be opened and chronyd was
built without IPv6 support.

Reported-by: Lonnie Abelbeck <lonnie@abelbeck.com>
---
 cmdmon.c |  2 +-
 ntp_io.c |  3 +++
 socket.c | 17 +++++++++++++++++
 socket.h |  3 +++
 4 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/cmdmon.c b/cmdmon.c
index ce5c719..ba6e985 100644
--- a/cmdmon.c
+++ b/cmdmon.c
@@ -159,7 +159,7 @@ open_socket(int family)
     case IPADDR_INET4:
     case IPADDR_INET6:
       port = CNF_GetCommandPort();
-      if (port == 0)
+      if (port == 0 || !SCK_IsFamilySupported(family))
         return INVALID_SOCK_FD;
 
       CNF_GetBindCommandAddress(family, &local_addr.ip_addr);
diff --git a/ntp_io.c b/ntp_io.c
index 4d9699d..7a70ff4 100644
--- a/ntp_io.c
+++ b/ntp_io.c
@@ -86,6 +86,9 @@ open_socket(int family, int local_port, int client_only, IPSockAddr *remote_addr
   int sock_fd, sock_flags, events = SCH_FILE_INPUT;
   IPSockAddr local_addr;
 
+  if (!SCK_IsFamilySupported(family))
+    return INVALID_SOCK_FD;
+
   if (!client_only)
     CNF_GetBindAddress(family, &local_addr.ip_addr);
   else
diff --git a/socket.c b/socket.c
index 466727f..677a142 100644
--- a/socket.c
+++ b/socket.c
@@ -1115,6 +1115,23 @@ SCK_Finalise(void)
 
 /* ================================================== */
 
+int
+SCK_IsFamilySupported(int family)
+{
+  switch (family) {
+    case IPADDR_INET4:
+      return 1;
+    case IPADDR_INET6:
+#ifdef FEAT_IPV6
+      return 1;
+#endif
+    default:
+      return 0;
+  }
+}
+
+/* ================================================== */
+
 void
 SCK_GetAnyLocalIPAddress(int family, IPAddr *local_addr)
 {
diff --git a/socket.h b/socket.h
index 823dfb6..ee44526 100644
--- a/socket.h
+++ b/socket.h
@@ -82,6 +82,9 @@ extern void SCK_Initialise(void);
 /* Finalisation function */
 extern void SCK_Finalise(void);
 
+/* Check if support for the IP family was enabled in the build */
+extern int SCK_IsFamilySupported(int family);
+
 /* Get the 0.0.0.0/::0 or 127.0.0.1/::1 address */
 extern void SCK_GetAnyLocalIPAddress(int family, IPAddr *local_addr);
 extern void SCK_GetLoopbackIPAddress(int family, IPAddr *local_addr);