Don't underflow datagram_address array

1 files changed, 4 insertions, 1 deletions

diff --git a/src/process.c b/src/process.c
index 10a2984a053..fd34eb08d9d 100644
--- a/src/process.c
+++ b/src/process.c
@@ -353,7 +353,10 @@ static struct sockaddr_and_len {
   int len;
 } datagram_address[FD_SETSIZE];
 #define DATAGRAM_CHAN_P(chan)   (datagram_address[chan].sa != 0)
-#define DATAGRAM_CONN_P(proc)   (PROCESSP (proc) && datagram_address[XPROCESS (proc)->infd].sa != 0)
+#define DATAGRAM_CONN_P(proc)                                           \
+  (PROCESSP (proc) &&                                                   \
+   XPROCESS (proc)->infd >= 0 &&                                        \
+   datagram_address[XPROCESS (proc)->infd].sa != 0)
 #else
 #define DATAGRAM_CHAN_P(chan)   (0)
 #define DATAGRAM_CONN_P(proc)   (0)