[PATCH net-next] netlink: Fix potential skb memleak in netlink_ack

From: Tao Chen
Date: Wed Nov 02 2022 - 08:08:56 EST


We should clean the skb resource if nlmsg_put/append failed
, so fix it.

Fiexs: commit 738136a0e375 ("netlink: split up copies in the
ack construction")
Signed-off-by: Tao Chen <chentao.kernel@xxxxxxxxxxxxxxxxx>
---
net/netlink/af_netlink.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index c6b8207e..9d73dae 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2500,7 +2500,7 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,

skb = nlmsg_new(payload + tlvlen, GFP_KERNEL);
if (!skb)
- goto err_bad_put;
+ goto err_skb;

rep = nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
NLMSG_ERROR, sizeof(*errmsg), flags);
@@ -2528,6 +2528,8 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
return;

err_bad_put:
+ kfree_skb(skb);
+err_skb:
NETLINK_CB(in_skb).sk->sk_err = ENOBUFS;
sk_error_report(NETLINK_CB(in_skb).sk);
}
--
2.2.1