Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Ryusuke Konishi <konishi.ryusuke@gmail.com>
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     Al Viro <viro@zeniv.linux.org.uk>,
        linux-nilfs <linux-nilfs@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Jiacheng Xu <stitch@zju.edu.cn>,
        Mudong Liang <mudongliangabcd@gmail.com>
Subject: [PATCH] nilfs2: fix use-after-free bug in nilfs_mdt_destroy()
Date:   Tue, 16 Aug 2022 02:51:14 +0900
Message-Id: <20220815175114.23576-1-konishi.ryusuke@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

In alloc_inode(), inode_init_always() could return -ENOMEM if
security_inode_alloc() fails.  If this happens for nilfs2,
nilfs_free_inode() is called without initializing inode->i_private and
nilfs_free_inode() wrongly calls nilfs_mdt_destroy(), which frees
uninitialized inode->i_private and can trigger a crash.

Fix this bug by initializing inode->i_private in nilfs_alloc_inode().

Link: https://lkml.kernel.org/r/CAFcO6XOcf1Jj2SeGt=jJV59wmhESeSKpfR0omdFRq+J9nD1vfQ@mail.gmail.com
Link: https://lkml.kernel.org/r/20211011030956.2459172-1-mudongliangabcd@gmail.com
Reported-by: butt3rflyh4ck <butterflyhuangxx@gmail.com>
Reported-by: Hao Sun <sunhao.th@gmail.com>
Reported-by: Jiacheng Xu <stitch@zju.edu.cn>
Reported-by: Mudong Liang <mudongliangabcd@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/nilfs2/super.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index ba108f915391..aca5614f1b44 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -159,6 +159,7 @@ struct inode *nilfs_alloc_inode(struct super_block *sb)
 	ii->i_cno = 0;
 	ii->i_assoc_inode = NULL;
 	ii->i_bmap = &ii->i_bmap_data;
+	ii->vfs_inode.i_private = NULL;
 	return &ii->vfs_inode;
 }
 
-- 
2.34.1