[PATCH] packet: Improve exception handling in fanout_add()

Markus Elfring
2023-12-31T15:39:18Z

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Sun, 31 Dec 2023 16:30:51 +0100

The kfree() function was called in some cases by the fanout_add() function
even if the passed variable contained a null pointer.
This issue was detected by using the Coccinelle software.

Thus use another label.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
net/packet/af_packet.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 5f1757a32842..0681d4f1ed85 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1712,14 +1712,14 @@ static int fanout_add(struct sock *sk, struct fanout_args *args)

err = -EALREADY;
if (po->fanout)
- goto out;
+ goto unlock_mutex;

if (type == PACKET_FANOUT_ROLLOVER ||
(type_flags & PACKET_FANOUT_FLAG_ROLLOVER)) {
err = -ENOMEM;
rollover = kzalloc(sizeof(*rollover), GFP_KERNEL);
if (!rollover)
- goto out;
+ goto unlock_mutex;
atomic_long_set(&rollover->num, 0);
atomic_long_set(&rollover->num_huge, 0);
atomic_long_set(&rollover->num_failed, 0);
@@ -1812,6 +1812,7 @@ static int fanout_add(struct sock *sk, struct fanout_args *args)

out:
kfree(rollover);
+unlock_mutex:
mutex_unlock(&fanout_mutex);
return err;
}
--
2.43.0