linux-kernel - Re: [PATCH v2 12/14] platform/x86/intel/ifs: Add current

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Date:   Sun, 13 Nov 2022 08:41:47 -0800
From:   "Joseph, Jithu" <jithu.joseph@...el.com>
To:     Borislav Petkov <bp@...en8.de>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        Thiago Macieira <thiago.macieira@...el.com>
CC:     "Luck, Tony" <tony.luck@...el.com>,
        "hdegoede@...hat.com" <hdegoede@...hat.com>,
        "markgross@...nel.org" <markgross@...nel.org>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
        "x86@...nel.org" <x86@...nel.org>, "hpa@...or.com" <hpa@...or.com>,
        "Raj, Ashok" <ashok.raj@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "platform-driver-x86@...r.kernel.org" 
        <platform-driver-x86@...r.kernel.org>,
        "patches@...ts.linux.dev" <patches@...ts.linux.dev>,
        "Shankar, Ravi V" <ravi.v.shankar@...el.com>,
        "Jimenez Gonzalez, Athenas" <athenas.jimenez.gonzalez@...el.com>,
        "Mehta, Sohil" <sohil.mehta@...el.com>
Subject: Re: [PATCH v2 12/14] platform/x86/intel/ifs: Add current_batch sysfs
 entry



On 11/13/2022 3:48 AM, Borislav Petkov wrote:

> 
> So instead of what the code does now:
> 
> +	snprintf(scan_path, sizeof(scan_path), "intel/ifs_%d/%02x-%02x-%02x-%02x.scan",
> +		 ifsd->test_num, boot_cpu_data.x86, boot_cpu_data.x86_model,
> +		 boot_cpu_data.x86_stepping, ifsd->cur_batch);
> 
> It would still use the *same* scan_path - /lib/firmware/intel/ifs_0/ -
> no one is proposing to give a full path name - it would only use the
> filename string - 06-8f-06-00.scan, for example - instead of the "0" in
> it to build that string.
> 
> And, ofcourse it would check the format of that string against family,
> model, stepping and sequence number (btw this way you drop your
> limitation of 256 for the sequence number which you don't really need
> either).
> 
> And then if the format passes, it would check the headers.

Do you think it is better to restrict filename input to confirm to
ff-mm-ss-xy.<test> format rather than accepting any string and treating it as
a file-name and trying to load it, if it is present ?

(Given that, before loading, We do intel_find_matching_signature(), which validates if the
 signature/pf entries in header confirms to the machine we are on before loading)

We did accepting file-name as input before [1] (except for validating if the filename confirms to ff-mm-ss format) 

> 
> And only if those pass too, then it would load.
> 


[1] https://lore.kernel.org/lkml/20220710160011.995800-1-jithu.joseph@intel.com/