From 5fdb358edc57f41292680a80e9f80f9c2c7f9742 Mon Sep 17 00:00:00 2001
From: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Date: Mon, 11 Jul 2016 18:36:05 +0100
Subject: [PATCH] Fix logic error in Linux netlink code.

This could cause dnsmasq to enter a tight loop on systems
with a very large number of network interfaces.

(cherry picked from commit 1d07667ac77c55b9de56b1b2c385167e0e0ec27a)
---
 src/netlink.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/netlink.c b/src/netlink.c
index 049247b..8cd51af 100644
--- a/src/netlink.c
+++ b/src/netlink.c
@@ -188,11 +188,17 @@ int iface_enumerate(int family, void *parm, int (*callback)())
 	}
 
       for (h = (struct nlmsghdr *)iov.iov_base; NLMSG_OK(h, (size_t)len); h = NLMSG_NEXT(h, len))
-	if (h->nlmsg_seq != seq || h->nlmsg_pid != netlink_pid || h->nlmsg_type == NLMSG_ERROR)
+	if (h->nlmsg_pid != netlink_pid || h->nlmsg_type == NLMSG_ERROR)
 	  {
 	    /* May be multicast arriving async */
 	    nl_async(h);
 	  }
+	else if (h->nlmsg_seq != seq)
+	  {
+	    /* May be part of incomplete response to previous request after
+	       ENOBUFS. Drop it. */
+	    continue;
+	  }
 	else if (h->nlmsg_type == NLMSG_DONE)
 	  return callback_ok;
 	else if (h->nlmsg_type == RTM_NEWADDR && family != AF_UNSPEC && family != AF_LOCAL)
-- 
2.26.2