linux-kernel - Re: [PATCH v3] scsi: require CAP_SYS_ADMIN to write to procfs interface

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Message-ID: <CAOviyagXOJE3JqYwd3hUNA+qL0cRVafDgma8FTvq9To9iBaYmQ@mail.gmail.com>
Date:   Sun, 5 Nov 2017 20:11:20 +1100
From:   Aleksa Sarai <cyphar@...har.com>
To:     Greg KH <greg@...ah.com>
Cc:     Aleksa Sarai <asarai@...e.de>,
        "James E.J. Bottomley" <jejb@...ux.vnet.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org,
        containers@...ts.linux-foundation.org,
        Valentin Rothberg <vrothberg@...e.com>, stable@...r.kernel.org,
        "Eric W. Biederman" <ebiederm@...ssion.com>
Subject: Re: [PATCH v3] scsi: require CAP_SYS_ADMIN to write to procfs interface

I've booted it on a few of my laptops, and nothing seemed to break. Is
there a particular test-suite you'd recommend that I run?

On Sun, Nov 5, 2017 at 6:31 PM, Greg KH <greg@...ah.com> wrote:
> On Sun, Nov 05, 2017 at 01:56:35PM +1100, Aleksa Sarai wrote:
>> Previously, the only capability effectively required to operate on the
>> /proc/scsi interface was CAP_DAC_OVERRIDE (or for some other files,
>> having an fsuid of GLOBAL_ROOT_UID was enough). This means that
>> semi-privileged processes could interfere with core components of a
>> system (such as causing a DoS by removing the underlying SCSI device of
>> the host's / mount).
>
> Given that the previous patch didn't even compile, I worry that you have
> not tested this at all to see what breaks/changes in userspace with this
> type of user-visable api change.
>
> What did you do to test this?
>
> thanks,
>
> greg k-h



-- 
Aleksa Sarai (cyphar)
www.cyphar.com