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From: Peilin Ye <yepeilin.cs@gmail.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: linux-fsdevel@vger.kernel.org, syzkaller-bugs@googlegroups.com,
	linux-kernel-mentees@lists.linuxfoundation.org,
	linux-kernel@vger.kernel.org
Subject: Re: [Linux-kernel-mentees] [PATCH] hfs, hfsplus: Fix NULL pointer dereference in hfs_find_init()
Date: Wed, 12 Aug 2020 13:23:35 -0400	[thread overview]
Message-ID: <20200812172335.GA897567@PWN> (raw)
In-Reply-To: <20200812085904.GA16441@kadam>

On Wed, Aug 12, 2020 at 11:59:04AM +0300, Dan Carpenter wrote:
> Yeah, the patch doesn't work at all.  I looked at one call tree and it
> is:
> 
> hfs_mdb_get() tries to allocate HFS_SB(sb)->ext_tree.
> 
> 	HFS_SB(sb)->ext_tree = hfs_btree_open(sb, HFS_EXT_CNID, hfs_ext_keycmp);
>                     ^^^^^^^^
> 
> hfs_btree_open() calls page = read_mapping_page(mapping, 0, NULL);
> read_mapping_page() calls mapping->a_ops->readpage() which leads to
> hfs_readpage() which leads to hfs_ext_read_extent() which calls
> res = hfs_find_init(HFS_SB(inode->i_sb)->ext_tree, &fd);
>                                          ^^^^^^^^

Thank you for pointing this out! I will try to come up with a better way
to fix it.

Peilin Ye

> So we need ->ext_tree to be non-NULL before we can set ->ext_tree to be
> non-NULL...  :/
> 
> I wonder how long this has been broken and if we should just delete the
> AFS file system.
> 
> regards,
> dan carpenter
> 
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees

WARNING: multiple messages have this Message-ID (diff)
From: Peilin Ye <yepeilin.cs@gmail.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-fsdevel@vger.kernel.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	syzkaller-bugs@googlegroups.com, linux-kernel@vger.kernel.org
Subject: Re: [Linux-kernel-mentees] [PATCH] hfs, hfsplus: Fix NULL pointer dereference in hfs_find_init()
Date: Wed, 12 Aug 2020 13:23:35 -0400	[thread overview]
Message-ID: <20200812172335.GA897567@PWN> (raw)
In-Reply-To: <20200812085904.GA16441@kadam>

On Wed, Aug 12, 2020 at 11:59:04AM +0300, Dan Carpenter wrote:
> Yeah, the patch doesn't work at all.  I looked at one call tree and it
> is:
> 
> hfs_mdb_get() tries to allocate HFS_SB(sb)->ext_tree.
> 
> 	HFS_SB(sb)->ext_tree = hfs_btree_open(sb, HFS_EXT_CNID, hfs_ext_keycmp);
>                     ^^^^^^^^
> 
> hfs_btree_open() calls page = read_mapping_page(mapping, 0, NULL);
> read_mapping_page() calls mapping->a_ops->readpage() which leads to
> hfs_readpage() which leads to hfs_ext_read_extent() which calls
> res = hfs_find_init(HFS_SB(inode->i_sb)->ext_tree, &fd);
>                                          ^^^^^^^^

Thank you for pointing this out! I will try to come up with a better way
to fix it.

Peilin Ye

> So we need ->ext_tree to be non-NULL before we can set ->ext_tree to be
> non-NULL...  :/
> 
> I wonder how long this has been broken and if we should just delete the
> AFS file system.
> 
> regards,
> dan carpenter
> 

  parent reply	other threads:[~2020-08-12 17:23 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-12  6:55 [Linux-kernel-mentees] [PATCH] hfs, hfsplus: Fix NULL pointer dereference in hfs_find_init() Peilin Ye
2020-08-12  6:55 ` Peilin Ye
2020-08-12  7:08 ` Greg Kroah-Hartman
2020-08-12  7:08   ` Greg Kroah-Hartman
2020-08-12  7:13   ` Peilin Ye
2020-08-12  7:13     ` Peilin Ye
2020-08-12  8:18     ` Greg Kroah-Hartman
2020-08-12  8:18       ` Greg Kroah-Hartman
2020-08-12 16:33       ` Peilin Ye
2020-08-12 16:33         ` Peilin Ye
2020-08-12  8:59     ` Dan Carpenter
2020-08-12  8:59       ` Dan Carpenter
2020-08-12 11:42       ` Big Budsupply
2020-08-12 17:23       ` Peilin Ye [this message]
2020-08-12 17:23         ` Peilin Ye
2020-08-12 20:24       ` Ernesto A. Fernández
2020-08-12 20:24         ` Ernesto A. Fernández
2020-08-12 20:34         ` Ernesto A. Fernández
2020-08-12 20:34           ` Ernesto A. Fernández

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