linux-kernel - Re: pwm: Fix double shift bug

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]

Date: Sat, 8 Jun 2024 13:37:45 +0200
From: Greg KH <gregkh@...uxfoundation.org>
To: "Ivan T. Ivanov" <iivanov@...e.de>
Cc: cve@...nel.org, linux-cve-announce@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: pwm: Fix double shift bug

On Wed, Jun 05, 2024 at 05:43:05PM +0300, Ivan T. Ivanov wrote:
> Hi,
> 
> I could argue that this is not CVE at all. It changes just bit positions.
> 
> -	PWMF_REQUESTED = 1 << 0,
> -	PWMF_EXPORTED = 1 << 1,
> +	PWMF_REQUESTED = 0,
> +	PWMF_EXPORTED = 1,
> 
> ie. before fix they 1 and 2 and after the fix 0, 1.
> 
> All call sites are using set/test_bit() on unsigned long flags.
> 
> Yes, double shift do not look right, but I don't see how
> this could lead to malfunction, let alone a CVE.

It could be an issue if the values were larger than 5 as the commit
says, but that's not the case here, so you are correct and this has now
been rejected as a cve.

Thanks for the review!

greg k-h