zebra: prevent crash when nhlfe is NULL

There exists a call path where the nhlfe_alloc can return NULL
for blackhole nexthops.  In this case we were still trying
to save the nhlfe pointer causing a crash when we attempted
to add it to a self-contained list.

Signed-off-by: Donald Sharp <sharpd@nvidia.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/zebra/zebra_mpls.c b/zebra/zebra_mpls.c
index f1a7c3e8c1..2f83fe4e28 100644
--- a/zebra/zebra_mpls.c
+++ b/zebra/zebra_mpls.c
@@ -1323,6 +1323,9 @@ static zebra_nhlfe_t *nhlfe_add(zebra_lsp_t *lsp, enum lsp_types_t lsp_type,
 	nhlfe = nhlfe_alloc(lsp, lsp_type, gtype, gate, ifindex, num_labels,
 			    labels);
 
+	if (!nhlfe)
+		return NULL;
+
 	/* Enqueue to LSP: primaries at head of list, backups at tail */
 	if (is_backup) {
 		SET_FLAG(nhlfe->flags, NHLFE_FLAG_IS_BACKUP);