[PATCH 5.4 046/108] net: sched: fix memory leak in tcindex_partial_destroy_work

Greg Kroah-Hartman
2021-07-26T16:05:53Z

From: Pavel Skripkin <paskripkin@gmail.com>

[ Upstream commit f5051bcece50140abd1a11a2d36dc3ec5484fc32 ]

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: 331b72922c5f ("net: sched: RCU cls_tcindex")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/sched/cls_tcindex.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/sched/cls_tcindex.c b/net/sched/cls_tcindex.c
index 3e81f87d0c89..684187a1fdb9 100644
--- a/net/sched/cls_tcindex.c
+++ b/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();
}
--
2.30.2