net: sched: fix memory leak in tcindex_partial_destroy_work

stable inclusion
from stable-5.10.54
commit 8e9662fde6d63c78eb1350f6167f64c9d71a865b
bugzilla: 175586 https://gitee.com/openeuler/kernel/issues/I4DVDU

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8e9662fde6d63c78eb1350f6167f64c9d71a865b

--------------------------------

[ Upstream commit f5051bce ]

Syzbot reported memory leak in tcindex_set_parms(). The problem was in
non-freed perfect hash in tcindex_partial_destroy_work().

In tcindex_set_parms() new tcindex_data is allocated and some fields from
old one are copied to new one, but not the perfect hash. Since
tcindex_partial_destroy_work() is the destroy function for old
tcindex_data, we need to free perfect hash to avoid memory leak.

Reported-and-tested-by: syzbot+f0bbb2287b8993d4fa74@syzkaller.appspotmail.com
Fixes: 331b7292 ("net: sched: RCU cls_tcindex")
Signed-off-by: NPavel Skripkin <paskripkin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

net/sched/cls_tcindex.c

@@ -278,6 +278,8 @@ static int tcindex_filter_result_init(struct tcindex_filter_result *r,
 			     TCA_TCINDEX_POLICE);
 }
 
+static void tcindex_free_perfect_hash(struct tcindex_data *cp);
+
 static void tcindex_partial_destroy_work(struct work_struct *work)
 {
 	struct tcindex_data *p = container_of(to_rcu_work(work),
@@ -285,7 +287,8 @@ static void tcindex_partial_destroy_work(struct work_struct *work)
 					      rwork);
 
 	rtnl_lock();
-	kfree(p->perfect);
+	if (p->perfect)
+		tcindex_free_perfect_hash(p);
 	kfree(p);
 	rtnl_unlock();
 }