netdev - Re: [PATCH v9 10/27] resource: harden resource

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: <a97f50df-5b0f-6ab5-80c6-531d4654c0b3@amd.com>
Date: Mon, 20 Jan 2025 16:26:42 +0000
From: Alejandro Lucero Palau <alucerop@....com>
To: Dan Williams <dan.j.williams@...el.com>, alejandro.lucero-palau@....com,
 linux-cxl@...r.kernel.org, netdev@...r.kernel.org, edward.cree@....com,
 davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com,
 edumazet@...gle.com, dave.jiang@...el.com, bhelgaas@...gle.com
Subject: Re: [PATCH v9 10/27] resource: harden resource_contains


On 1/20/25 16:16, Alejandro Lucero Palau wrote:
> Adding Bjorn to the thread. Not sure if he just gets the email being 
> in an Acked-by line.
>
>
> On 1/20/25 16:10, Alejandro Lucero Palau wrote:
>>
>> On 1/18/25 02:03, Dan Williams wrote:
>>> alejandro.lucero-palau@ wrote:
>>>> From: Alejandro Lucero <alucerop@....com>
>>>>
>>>> While resource_contains checks for IORESOURCE_UNSET flag for the
>>>> resources given, if r1 was initialized with 0 size, the function
>>>> returns a false positive. This is so because resource start and
>>>> end fields are unsigned with end initialised to size - 1 by current
>>>> resource macros.
>>>>
>>>> Make the function to check for the resource size for both resources
>>>> since r2 with size 0 should not be considered as valid for the 
>>>> function
>>>> purpose.
>>>>
>>>> Signed-off-by: Alejandro Lucero <alucerop@....com>
>>>> Suggested-by: Alison Schofield <alison.schofield@...el.com>
>>>> Reviewed-by: Alison Schofield <alison.schofield@...el.com>
>>>> Acked-by: Bjorn Helgaas <bhelgaas@...gle.com>
>>>> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
>>>> ---
>>>>   include/linux/ioport.h | 2 ++
>>>>   1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/include/linux/ioport.h b/include/linux/ioport.h
>>>> index 5385349f0b8a..7ba31a222536 100644
>>>> --- a/include/linux/ioport.h
>>>> +++ b/include/linux/ioport.h
>>>> @@ -296,6 +296,8 @@ static inline unsigned long 
>>>> resource_ext_type(const struct resource *res)
>>>>   /* True iff r1 completely contains r2 */
>>>>   static inline bool resource_contains(const struct resource *r1, 
>>>> const struct resource *r2)
>>>>   {
>>>> +    if (!resource_size(r1) || !resource_size(r2))
>>>> +        return false;
>>> I just worry that some code paths expect the opposite, that it is ok to
>>> pass zero size resources and get a true result.
>>
>>
>> That is an interesting point, I would say close to philosophic 
>> arguments. I guess you mean the zero size resource being the one that 
>> is contained inside the non-zero one, because the other option is 
>> making my vision blurry. In fact, even that one makes me feel trapped 
>> in a window-less room, in summer, with a bunch of economists, I mean 
>> philosophers, and my phone without signal for emergency calls.
>>

I forgot to make my strongest point :-). If someone assumes it is or it 
should be true a zero-size resource is contained inside a non zero-size 
resource, we do not need to call a function since it is always true 
regardless of the non zero-size resource ... that headache is starting 
again ...


>>
>> But maybe it is just  my lack of understanding and there exists a 
>> good reason for this possibility.
>>
>>
>> Bjorn, I guess the ball is in your side ...
>>
>>> Did you audit existing callers?