From: Balbir Singh <bsingharora@gmail.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Waiman Long <longman@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
David Howells <dhowells@redhat.com>,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
James Morris <jmorris@namei.org>,
"Serge E. Hallyn" <serge@hallyn.com>,
linux-mm@kvack.org, keyrings@vger.kernel.org,
linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Joe Perches <joe@perches.com>,
David Rientjes <rientjes@google.com>
Subject: Re: [PATCH v3] mm: Add kvfree_sensitive() for freeing sensitive data objects
Date: Sun, 17 May 2020 10:27:39 +1000 [thread overview]
Message-ID: <f779dea1-3b50-e354-3914-7394b4473f5b@gmail.com> (raw)
In-Reply-To: <20200514120018.GA16070@bombadil.infradead.org>
On 14/5/20 10:00 pm, Matthew Wilcox wrote:
> On Thu, May 14, 2020 at 09:00:40PM +1000, Balbir Singh wrote:
>> I wonder if the right thing to do is also to disable pre-emption, just so that the thread does not linger on with sensitive data.
>>
>> void kvfree_sensitive(const void *addr, size_t len)
>> {
>> preempt_disable();
>> if (likely(!ZERO_OR_NULL_PTR(addr))) {
>> memzero_explicit((void *)addr, len);
>> kvfree(addr);
>> }
>> preempt_enable();
>> }
>> EXPORT_SYMBOL(kvfree_sensitive);
>
> If it's _that_ sensitive then the caller should have disabled preemption.
> Because preemption could otherwise have occurred immediately before
> kvfree_sensitive() was called.
>
May be, but the callers of the API have to be explictly aware of the contract.
I don't disagree with you on what you've said, but I was referring to the
intent of freeing sensitive data vs the turn around time for doing so.
Balbir Singh.
next prev parent reply other threads:[~2020-05-17 0:27 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-07 20:03 [PATCH v3] mm: Add kvfree_sensitive() for freeing sensitive data objects Waiman Long
2020-04-07 20:09 ` Linus Torvalds
2020-04-07 20:19 ` David Howells
2020-04-07 20:24 ` Waiman Long
2020-04-07 20:21 ` David Howells
2020-05-05 20:35 ` Andrew Morton
2020-05-06 1:29 ` Waiman Long
2020-04-07 20:31 ` Joe Perches
2020-04-07 20:45 ` Waiman Long
2020-04-07 21:01 ` Linus Torvalds
2020-04-07 21:24 ` Uladzislau Rezki
2020-04-07 21:30 ` Linus Torvalds
2020-04-07 22:12 ` Matthew Wilcox
2020-04-08 0:35 ` Joe Perches
2020-04-08 13:38 ` Jarkko Sakkinen
2020-05-01 23:22 ` Eric Biggers
2020-05-04 2:57 ` Waiman Long
2020-05-14 11:00 ` Balbir Singh
2020-05-14 12:00 ` Matthew Wilcox
2020-05-14 12:08 ` Joe Perches
2020-05-17 0:27 ` Balbir Singh [this message]
2020-05-17 0:44 ` Matthew Wilcox
2020-05-18 2:39 ` Waiman Long
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=f779dea1-3b50-e354-3914-7394b4473f5b@gmail.com \
--to=bsingharora@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=dhowells@redhat.com \
--cc=jarkko.sakkinen@linux.intel.com \
--cc=jmorris@namei.org \
--cc=joe@perches.com \
--cc=keyrings@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=longman@redhat.com \
--cc=rientjes@google.com \
--cc=serge@hallyn.com \
--cc=torvalds@linux-foundation.org \
--cc=willy@infradead.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).