linux-kernel - Re: [PATCH v7 3/8] firmware: Rename FW_OPT_NOFALLBACK to FW_OPT_NOFALLBACK

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 for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 14 Nov 2019 21:22:16 +0100
From:   Hans de Goede <hdegoede@...hat.com>
To:     Luis Chamberlain <mcgrof@...nel.org>
Cc:     Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Scott Branden <scott.branden@...adcom.com>,
        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        Jonathan Corbet <corbet@....net>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Peter Jones <pjones@...hat.com>,
        Dave Olsthoorn <dave@...aar.me>, x86@...nel.org,
        platform-driver-x86@...r.kernel.org, linux-efi@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-input@...r.kernel.org
Subject: Re: [PATCH v7 3/8] firmware: Rename FW_OPT_NOFALLBACK to
 FW_OPT_NOFALLBACK_SYSFS

Hi,

On 11-10-2019 17:02, Luis Chamberlain wrote:
> On Fri, Oct 04, 2019 at 04:50:51PM +0200, Hans de Goede wrote:
>> diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c
>> index 62ee90b4db56..665b350419cb 100644
>> --- a/drivers/base/firmware_loader/fallback.c
>> +++ b/drivers/base/firmware_loader/fallback.c
>> @@ -606,7 +606,7 @@ static bool fw_run_sysfs_fallback(enum fw_opt opt_flags)
>>   		return false;
>>   	}
>>   
>> -	if ((opt_flags & FW_OPT_NOFALLBACK))
>> +	if ((opt_flags & FW_OPT_NOFALLBACK_SYSFS))
>>   		return false;
>>   
>>   	/* Also permit LSMs and IMA to fail firmware sysfs fallback */
>> @@ -630,10 +630,11 @@ static bool fw_run_sysfs_fallback(enum fw_opt opt_flags)
>>    * interface. Userspace is in charge of loading the firmware through the sysfs
>>    * loading interface. This sysfs fallback mechanism may be disabled completely
>>    * on a system by setting the proc sysctl value ignore_sysfs_fallback to true.
>> - * If this false we check if the internal API caller set the @FW_OPT_NOFALLBACK
>> - * flag, if so it would also disable the fallback mechanism. A system may want
>> - * to enfoce the sysfs fallback mechanism at all times, it can do this by
>> - * setting ignore_sysfs_fallback to false and force_sysfs_fallback to true.
>> + * If this false we check if the internal API caller set the
>           ignore_sysfs_fallback set to true or force_sysfs_fallback is
> 	 set to false

I do not think that that is correct, looking at the code the order of
checks is:

	if (fw_fallback_config.ignore_sysfs_fallback)
		BAIL

	if (opt_flags & FW_OPT_NOFALLBACK_SYSFS)
		BAIL

	if (fw_fallback_config.force_sysfs_fallback)
		DO_FALLBACK (and return)

	if (!(opt_flags & FW_OPT_USERHELPER))
		BAIL

	DO_FALLBACK

So the original comment seems correct as FW_OPT_NOFALLBACK trumps / has
higher prio then force_sysfs_fallback.

Anyways I do not believe that fixing up/rewording this comment (if it needs
fixing) belongs in the commit/patch. This patch is purely about renaming
FW_OPT_NOFALLBACK to FW_OPT_NOFALLBACK_SYSFS, the lines changed in this
chunk are not changed, they are merely re-word/line-wrapped with the
exception of fixing the enfoce typo to enforce, as mentioned in the
commit message.

Regards,

Hans