[PATCH v3] ocfs2: quota_local: fix possible uninitialized-variable access in ocfs2_local_read_info()

From: Tuo Li <islituo@gmail.com>
To: mark@fasheh.com, jlbec@evilplan.org, joseph.qi@linux.alibaba.com
Cc: ocfs2-devel@oss.oracle.com, linux-kernel@vger.kernel.org,
	baijiaju1990@gmail.com, Tuo Li <islituo@gmail.com>,
	TOTE Robot <oslab@tsinghua.edu.cn>
Subject: [PATCH v3] ocfs2: quota_local: fix possible uninitialized-variable access in ocfs2_local_read_info()
Date: Tue,  3 Aug 2021 20:18:32 -0700	[thread overview]
Message-ID: <20210804031832.57154-1-islituo@gmail.com> (raw)

A memory block is allocated through kmalloc(), and its return value is
assigned to the pointer oinfo. However, oinfo->dqi_gqinode is not
initialized but it is accessed in:
  iput(oinfo->dqi_gqinode);

To fix this possible uninitialized-variable access, assign NULL to
oinfo->dqi_gqinode, and add ocfs2_qinfo_lock_res_init()
behind the assignment in ocfs2_local_read_info(). Remove
ocfs2_qinfo_lock_res_init() in ocfs2_global_read_info().

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Tuo Li <islituo@gmail.com>
---
v3:
* Update description.
* Assign NULL to oinfo->dqi_gqinode, and add ocfs2_qinfo_lock_res_init()
behind the assignment in ocfs2_local_read_info(). Remove
ocfs2_qinfo_lock_res_init() in ocfs2_global_read_info()
  Thank Joseph Qi for helpful advice.
v2:
* Replace kzalloc() with NULL assignment to oinfo->dqi_gqinode.
  Thank Joseph Qi for helpful advice.
---
 fs/ocfs2/quota_global.c | 1 -
 fs/ocfs2/quota_local.c  | 2 ++
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/ocfs2/quota_global.c b/fs/ocfs2/quota_global.c
index eda83487c9ec..f033de733adb 100644
--- a/fs/ocfs2/quota_global.c
+++ b/fs/ocfs2/quota_global.c
@@ -357,7 +357,6 @@ int ocfs2_global_read_info(struct super_block *sb, int type)
 	}
 	oinfo->dqi_gi.dqi_sb = sb;
 	oinfo->dqi_gi.dqi_type = type;
-	ocfs2_qinfo_lock_res_init(&oinfo->dqi_gqlock, oinfo);
 	oinfo->dqi_gi.dqi_entry_size = sizeof(struct ocfs2_global_disk_dqblk);
 	oinfo->dqi_gi.dqi_ops = &ocfs2_global_ops;
 	oinfo->dqi_gqi_bh = NULL;
diff --git a/fs/ocfs2/quota_local.c b/fs/ocfs2/quota_local.c
index b1a8b046f4c2..0e4b16d4c037 100644
--- a/fs/ocfs2/quota_local.c
+++ b/fs/ocfs2/quota_local.c
@@ -702,6 +702,8 @@ static int ocfs2_local_read_info(struct super_block *sb, int type)
 	info->dqi_priv = oinfo;
 	oinfo->dqi_type = type;
 	INIT_LIST_HEAD(&oinfo->dqi_chunk);
+	oinfo->dqi_gqinode = NULL;
+	ocfs2_qinfo_lock_res_init(&oinfo->dqi_gqlock, oinfo);
 	oinfo->dqi_rec = NULL;
 	oinfo->dqi_lqi_bh = NULL;
 	oinfo->dqi_libh = NULL;
-- 
2.25.1

