From: Vaibhav Jain <vaibhav@linux.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
linuxppc-dev@lists.ozlabs.org, linux-nvdimm@lists.01.org
Cc: Oliver O'Halloran <oohall@gmail.com>,
Dan Williams <dan.j.williams@intel.com>,
Ira Weiny <ira.weiny@intel.com>,
Santosh Sivaraj <santosh@fossix.org>
Subject: Re: [PATCH] powerpc/papr_scm: Limit the readability of 'perf_stats' sysfs attribute
Date: Wed, 19 Aug 2020 14:49:25 +0530 [thread overview]
Message-ID: <87imdfgfhe.fsf@vajain21.in.ibm.com> (raw)
In-Reply-To: <87imdm9frg.fsf@mpe.ellerman.id.au>
Thanks Aneesh and Mpe for reviewing this patch.
Michael Ellerman <mpe@ellerman.id.au> writes:
> "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes:
[snip]
>>>
>>> + /* Allow access only to perfmon capable users */
>>> + if (!perfmon_capable())
>>> + return -EACCES;
>>> +
>>
>> An access check is usually done in open(). This is the read callback IIUC.
>
> Yes. Otherwise an unprivileged user can open the file, and then trick a
> suid program into reading from it.
Agree, but since the 'open()' for this sysfs attribute is handled
by kern-fs, AFAIK dont see any direct way to enforce this policy.
Only other way it seems to me is to convert the 'perf_stats' DEVICE_ATTR_RO
to DEVICE_ATTR_ADMIN_RO.
>
> cheers
--
Cheers
~ Vaibhav
prev parent reply other threads:[~2020-08-19 9:21 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-13 4:34 [PATCH] powerpc/papr_scm: Limit the readability of 'perf_stats' sysfs attribute Vaibhav Jain
2020-08-13 12:31 ` Aneesh Kumar K.V
2020-08-14 1:29 ` Michael Ellerman
2020-08-19 9:19 ` Vaibhav Jain [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87imdfgfhe.fsf@vajain21.in.ibm.com \
--to=vaibhav@linux.ibm.com \
--cc=aneesh.kumar@linux.ibm.com \
--cc=dan.j.williams@intel.com \
--cc=ira.weiny@intel.com \
--cc=linux-nvdimm@lists.01.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mpe@ellerman.id.au \
--cc=oohall@gmail.com \
--cc=santosh@fossix.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).