linux-kernel - Re: [PATCH] vfat: fix uninitialized i

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <87o6sbz5kd.fsf@mail.parknet.co.jp>
Date: Wed, 20 Aug 2025 00:36:50 +0900
From: OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
To: zhoumin <teczm@...mail.com>
Cc: linux-kernel@...r.kernel.org
Subject: Re: [PATCH] vfat: fix uninitialized i_pos error

zhoumin <teczm@...mail.com> writes:

> The i_pos field remains uninitialized when fat_fs_error_ratelimit() reports
> error, e.g.,
>
> 	[ 1642.703550] FAT-fs (loop0): error, fat_get_cluster: invalid
> 	cluster chain (i_pos 0)
>
> Since i_pos is assigned in fat_attach after fat_fill_inode, the error
> message lacks useful debug info.
>
> Path:
> vfat_lookup
> 	fat_build_inode
> 		fat_fill_inode
> 			fat_calc_dir_size
>           			fat_get_cluster /* report error */
>       	fat_attach  /* i_pos assigned here */

No. It is initialized as 0, and it must be unavailable outside
between fat_attach and fat_detach.

IOW, this is introducing the race.

Thanks.
-- 
OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>