releases/4.9.259/ocfs2-fix-a-use-after-free-on-error.patch

From eaa3128cfbc41f564b958d6063a3fde266e50ed3 Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Wed, 24 Feb 2021 12:00:41 -0800
Subject: ocfs2: fix a use after free on error

From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit c57d117f2b2f2a19b570c36f2819ef8d8210af20 ]

The error handling in this function frees "reg" but it is still on the
"o2hb_all_regions" list so it will lead to a use after freew.  Joseph Qi
points out that we need to clear the bit in the "o2hb_region_bitmap" as
well

Link: https://lkml.kernel.org/r/YBk4M6HUG8jB/jc7@mwanda
Fixes: 1cf257f51191 ("ocfs2: fix memory leak")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/ocfs2/cluster/heartbeat.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 5e8709aa1e7ec..89c71d32dc05b 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -2155,7 +2155,7 @@ static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *g
 			o2hb_nego_timeout_handler,
 			reg, NULL, &reg->hr_handler_list);
 	if (ret)
-		goto free;
+		goto remove_item;
 
 	ret = o2net_register_handler(O2HB_NEGO_APPROVE_MSG, reg->hr_key,
 			sizeof(struct o2hb_nego_msg),
@@ -2174,6 +2174,12 @@ static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *g
 
 unregister_handler:
 	o2net_unregister_handler_list(&reg->hr_handler_list);
+remove_item:
+	spin_lock(&o2hb_live_lock);
+	list_del(&reg->hr_all_item);
+	if (o2hb_global_heartbeat_active())
+		clear_bit(reg->hr_region_num, o2hb_region_bitmap);
+	spin_unlock(&o2hb_live_lock);
 free:
 	kfree(reg);
 	return ERR_PTR(ret);
-- 
2.27.0