linux-kernel - Re: [PATCH 1/1] mtd: ubi: skip programming unused bits in ubi headers

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] [day] [month] [year] [list]

Message-ID: <954318808.156230.1762506755899.JavaMail.zimbra@nod.at>
Date: Fri, 7 Nov 2025 10:12:35 +0100 (CET)
From: Richard Weinberger <richard@....at>
To: Cheng Ming Lin <linchengming884@...il.com>
Cc: Miquel Raynal <miquel.raynal@...tlin.com>, 
	chengzhihao1 <chengzhihao1@...wei.com>, 
	Vignesh Raghavendra <vigneshr@...com>, 
	linux-mtd <linux-mtd@...ts.infradead.org>, 
	linux-kernel <linux-kernel@...r.kernel.org>, 
	Alvin Zhou <alvinzhou@...c.com.tw>, leoyu <leoyu@...c.com.tw>, 
	Cheng Ming Lin <chengminglin@...c.com.tw>
Subject: Re: [PATCH 1/1] mtd: ubi: skip programming unused bits in ubi
 headers

----- Ursprüngliche Mail -----
> Von: "Cheng Ming Lin" <linchengming884@...il.com>
>> Here I am reaching the limits of my UBI knowledge, so I would prefer
>> Richard to (in)validate what I am saying, but AFAIU, the VID header can
>> be literally anywhere in the page, not just at the start or end of a
>> subpage, so in the vid_hdr_shift I would expect some extra maths to
>> happen, no?

Good catch!
I had to read the code change twice to see the problem, though. :-S

> I understand your point now. If the VID header is not guaranteed to be
> at the start or end of a subpage, then yes, my current logic needs to be
> reworked to cover that case.

Yes. This can be configured using ubiattach --vid-hdr-offset ...
With nandsim you can test all kind of combinations.

Thanks,
//richard