[PATCH 4/4] libabis: fix segfault on malformed ipaccess RSL link

[Alexander Huemer]

This patch fixes a segfault that occured when a ipaccess RSL link gets
closed unexpectedly.
The segfault can be provoked by connecting to the RSL port with ncat and
hitting ^C.
---
 openbsc/src/libabis/input/ipaccess.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/openbsc/src/libabis/input/ipaccess.c b/openbsc/src/libabis/input/ipaccess.c
index 1427118..cc2a7a0 100644
--- a/openbsc/src/libabis/input/ipaccess.c
+++ b/openbsc/src/libabis/input/ipaccess.c
@@ -429,12 +429,15 @@ static int ipaccess_drop(struct e1inp_ts *ts, struct osmo_fd *bfd)
 	struct e1inp_sign_link *link;
 	int bts_nr;
 
-	if (!ts) {
+	if (!ts || !bfd->data) {
 		/*
 		 * If we don't have a TS this means that this is a RSL
 		 * connection but we are not past the authentication
 		 * handling yet. So we can safely delete this bfd and
 		 * wait for a reconnect.
+		 * If we don't have bfd->data this means that a RSL
+		 * connection was accept()ed, but nothing was recv()ed
+		 * and the connection gets close()ed.
 		 */
 		osmo_fd_unregister(bfd);
 		close(bfd->fd);
-- 
1.7.5.rc3