Do not crash when ifa_addr is null

Summary:
This happens with tun interfaces, which are layer 3 only.

Fixes T109.

Reviewers: roy

Reviewed By: roy

Maniphest Tasks: T109

Differential Revision: https://dev.marples.name/D103

1 files changed, 2 insertions, 0 deletions

diff --git a/parpd.c b/parpd.c
index 0bfcc71..a178696 100644
--- a/parpd.c
+++ b/parpd.c
@@ -474,6 +474,8 @@ ifa_valid(int s, const struct ifaddrs *ifa)
 {
 	struct ifreq ifr;
 
+	if (ifa->ifa_addr == NULL)
+		return 0;
 #ifdef AF_LINK
 	if (ifa->ifa_addr->sa_family != AF_LINK)
 		return 0;