linux-hardening - Re: [PATCH v2 06/14] mfd: zl3073x: Add macros for device registers access

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: <4f1633ca-bc75-4e81-8747-52605ce352d8@redhat.com>
Date: Sun, 13 Apr 2025 12:18:07 +0200
From: Ivan Vecera <ivecera@...hat.com>
To: Andy Shevchenko <andy.shevchenko@...il.com>
Cc: Krzysztof Kozlowski <krzk@...nel.org>, netdev@...r.kernel.org,
 Vadim Fedorenko <vadim.fedorenko@...ux.dev>,
 Arkadiusz Kubalewski <arkadiusz.kubalewski@...el.com>,
 Jiri Pirko <jiri@...nulli.us>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Prathosh Satish <Prathosh.Satish@...rochip.com>,
 Lee Jones <lee@...nel.org>, Kees Cook <kees@...nel.org>,
 Andy Shevchenko <andy@...nel.org>, Andrew Morton
 <akpm@...ux-foundation.org>, Michal Schmidt <mschmidt@...hat.com>,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-hardening@...r.kernel.org
Subject: Re: [PATCH v2 06/14] mfd: zl3073x: Add macros for device registers
 access



On 10. 04. 25 7:53 odp., Andy Shevchenko wrote:
> On Thu, Apr 10, 2025 at 11:21 AM Ivan Vecera <ivecera@...hat.com> wrote:
>> On 10. 04. 25 9:17 dop., Krzysztof Kozlowski wrote:
>>> On 09/04/2025 16:42, Ivan Vecera wrote:
> 
> ...
> 
>>>> +    WARN_ON(idx >= (_num));                                         \
>>>
>>> No need to cause panic reboots. Either review your code so this does not
>>> happen or properly handle.
>>
>> Ack, will replace by
>>
>> if (idx >= (_num))
>>          return -EINVAL
> 
> If these functions are called under regmap_read() / regmap_write() the
> above is a dead code. Otherwise you need to configure regmap correctly
> (in accordance with the HW registers layout and their abilities to be
> written or read or reserved or special combinations).
> 
Hi Andy,
these functions are not called under regmap_{read,write} but above. Some 
(non-mailboxed) registers are indexed.

E.g. register ref_freq is defined as 4-bytes for 10 input references:
ref0: address 0x144-0x147
ref1: address 0x148-0x14b
...

So the caller (this mfd driver or dpll driver) will access it as:
zl3073x_read_ref_freq(zldev, idx, &value);

and this helper then computes the addr value according base (0x144) and 
provided index with ref number and then calls regmap_*read().

And the 'if' check is just for a sanity check that the caller does not 
provide wrong index and if so return -EINVAL.

I.