[PATCH v2] Fix NULL pointer deref due to filtering on fork

From: Anjali Kulkarni
Date: Wed Oct 11 2023 - 01:12:42 EST


cn_netlink_send_mult() should be called with filter & filter_data only
for EXIT case. For all other events, filter & filter_data should be
NULL.

Fixes: 2aa1f7a1f47c ("connector/cn_proc: Add filtering to fix some bugs")
Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
Closes: https://urldefense.com/v3/__https://lore.kernel.org/oe-lkp/202309201456.84c19e27-oliver.sang@intel.com__;!!ACWV5N9M2RV99hQ!PgqlHq_nOe_KlyKkB9Mm_S8QstTJvicjuENwskatuuQK05KPuFw-KvRZeOH8iuEAMjRhkxEMPKJJnLcaT8zrPf9aqNs$

Signed-off-by: Anjali Kulkarni <anjali.k.kulkarni@xxxxxxxxxx>
---
drivers/connector/cn_proc.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c
index 05d562e9c8b1..01e17f18d187 100644
--- a/drivers/connector/cn_proc.c
+++ b/drivers/connector/cn_proc.c
@@ -104,13 +104,13 @@ static inline void send_msg(struct cn_msg *msg)
if (filter_data[0] == PROC_EVENT_EXIT) {
filter_data[1] =
((struct proc_event *)msg->data)->event_data.exit.exit_code;
+ cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT,
+ cn_filter, (void *)filter_data);
} else {
- filter_data[1] = 0;
+ cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT,
+ NULL, NULL);
}

- cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT,
- cn_filter, (void *)filter_data);
-
local_unlock(&local_event.lock);
}

--
2.42.0