[nft PATCH 2/3] monitor: Fix for use after free when printing map elements

[Phil Sutter <phil@nwl.cc>]

When populating the dummy set, 'data' field must be cloned just like
'key' field.

Fixes: 343a51702656a ("src: store expr, not dtype to track data in sets")
Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 src/monitor.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/monitor.c b/src/monitor.c
index 84505eb914bf6..53a8bcd4641d1 100644
--- a/src/monitor.c
+++ b/src/monitor.c
@@ -401,7 +401,8 @@ static int netlink_events_setelem_cb(const struct nlmsghdr *nlh, int type,
 	 */
 	dummyset = set_alloc(monh->loc);
 	dummyset->key = expr_clone(set->key);
-	dummyset->data = set->data;
+	if (set->data)
+		dummyset->data = expr_clone(set->data);
 	dummyset->flags = set->flags;
 	dummyset->init = set_expr_alloc(monh->loc, set);
 
-- 
2.24.1