ext4: fix possible use after free in ext4_quota_enable

The function frees qf_inode via iput but then pass qf_inode to lockdep_set_quota_inode on the failure path. This may result in a use-after-free bug. The patch frees df_inode only when it is never used. Fixes: daf647d ("ext4: add lockdep annotations for i_data_sem") Cc: [email protected] # 4.6 Reviewed-by: Jan Kara <[email protected]> Signed-off-by: Pan Bian <[email protected]> Signed-off-by: Theodore Ts'o <[email protected]>
adn770 · Dec 4, 2018 · 61157b2 · 61157b2
1 parent 96f1e09
commit 61157b2
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
@@ -5713,9 +5713,9 @@ static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
 	qf_inode->i_flags |= S_NOQUOTA;
 	lockdep_set_quota_inode(qf_inode, I_DATA_SEM_QUOTA);
 	err = dquot_enable(qf_inode, type, format_id, flags);
-	iput(qf_inode);
 	if (err)
 		lockdep_set_quota_inode(qf_inode, I_DATA_SEM_NORMAL);
+	iput(qf_inode);
 
 	return err;
 }