Re: kern/56160: Mount ntfs usb disk

["J. Hannken-Illjes" <hannken%eis.cs.tu-bs.de@localhost>]

The following reply was made to PR kern/56160; it has been noted by GNATS.

From: "J. Hannken-Illjes" <hannken%eis.cs.tu-bs.de@localhost>
To: NetBSD GNATS <gnats-bugs%netbsd.org@localhost>
Cc: 
Subject: Re: kern/56160: Mount ntfs usb disk
Date: Thu, 13 May 2021 10:10:36 +0200

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 This disk has an unusual format, what happens is:
 
 - On mounting the disk we want to preload critical nodes,
   first node 0 (MFT).
 
 - During load we look for attribute 0x30 (NTFS_A_NAME) of node 0.
 
 - While this attribute is usually resident this disk stores it
   through its attribute 0x20 (NTFS_A_ATTRLIST) in node 16.
 
 - Now happens what Michael expected:  trying to load node 16
   we use the not-yet initialized node 0 (MFT) to read the
   attribute node and crash on null pointer dereference.
 
 Excerpt from "ntfsinfo -i 0 -v":
 
 Dumping Inode 0 (0x0)
 Dumping attribute $STANDARD_INFORMATION (0x10) from mft record 0 (0x0)
 Dumping attribute $ATTRIBUTE_LIST (0x20) from mft record 0 (0x0)
         Dumping attribute list:
                 Attribute type: 0x10
                 Attribute type: 0x30
                         Starting VCN:   0 (0x0)
                         MFT reference:  16 (0x10)
                 Attribute type: 0x80
                 Attribute type: 0x80
                 Attribute type: 0xb0
         End of attribute list reached.
 Dumping attribute $FILE_NAME (0x30) from mft record 16 (0x10)
         File Creation Time:      Wed Oct 31 13:52:23 2012 UTC
         Filename:                '$MFT'
 
 --
 J. Hannken-Illjes - hannken%eis.cs.tu-bs.de@localhost - TU Braunschweig
 
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