From: Michael Ellerman <mpe@ellerman.id.au>
To: Anjali K <anjalik@linux.ibm.com>, Kees Cook <kees@kernel.org>
Cc: linuxppc-dev@lists.ozlabs.org, npiggin@gmail.com,
naveen@kernel.org, christophe.leroy@csgroup.eu,
gustavoars@kernel.org, linux-hardening@vger.kernel.org,
vishalc@linux.ibm.com
Subject: Re: [PATCH] powerpc/pseries: Whitelist dtl slub object for copying to userspace
Date: Fri, 21 Jun 2024 21:38:41 +1000 [thread overview]
Message-ID: <87zfrecypq.fsf@mail.lhotse> (raw)
In-Reply-To: <45c38d92-8d7c-466c-833d-0c2aa389eeda@linux.ibm.com>
Anjali K <anjalik@linux.ibm.com> writes:
> Hi Michael
>
> On 18/06/24 12:41, Michael Ellerman wrote:
>> I guess there isn't a kmem_cache_create_user_readonly() ?
> Thank you for your review.
>
> My understanding of the question is whether there's a way to whitelist a
> region such that it can be copied to userspace, but not written to using
> copy_from_user().
Yes that's what I meant, and I pretty much worked that out from looking
at the implementation, but was hoping Kees would tell me it was there
somewhere, or implement it :) Apologies for being cryptic.
> No, we don't have a function to whitelist only for copy_to_user() and not
> copy_from_user().
Yep. I'll take this patch as-is, I think we've established that it's
pretty low risk to whitelist the whole cache.
cheers
WARNING: multiple messages have this Message-ID (diff)
From: Michael Ellerman <mpe@ellerman.id.au>
To: Anjali K <anjalik@linux.ibm.com>, Kees Cook <kees@kernel.org>
Cc: npiggin@gmail.com, naveen@kernel.org,
christophe.leroy@csgroup.eu, gustavoars@kernel.org,
linux-hardening@vger.kernel.org, vishalc@linux.ibm.com,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc/pseries: Whitelist dtl slub object for copying to userspace
Date: Fri, 21 Jun 2024 21:38:41 +1000 [thread overview]
Message-ID: <87zfrecypq.fsf@mail.lhotse> (raw)
In-Reply-To: <45c38d92-8d7c-466c-833d-0c2aa389eeda@linux.ibm.com>
Anjali K <anjalik@linux.ibm.com> writes:
> Hi Michael
>
> On 18/06/24 12:41, Michael Ellerman wrote:
>> I guess there isn't a kmem_cache_create_user_readonly() ?
> Thank you for your review.
>
> My understanding of the question is whether there's a way to whitelist a
> region such that it can be copied to userspace, but not written to using
> copy_from_user().
Yes that's what I meant, and I pretty much worked that out from looking
at the implementation, but was hoping Kees would tell me it was there
somewhere, or implement it :) Apologies for being cryptic.
> No, we don't have a function to whitelist only for copy_to_user() and not
> copy_from_user().
Yep. I'll take this patch as-is, I think we've established that it's
pretty low risk to whitelist the whole cache.
cheers
next prev parent reply other threads:[~2024-06-21 11:38 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-14 17:38 [PATCH] powerpc/pseries: Whitelist dtl slub object for copying to userspace Anjali K
2024-06-14 17:38 ` Anjali K
2024-06-17 10:37 ` Srikar Dronamraju
2024-06-17 10:37 ` Srikar Dronamraju
2024-06-17 17:59 ` Kees Cook
2024-06-17 17:59 ` Kees Cook
2024-06-18 7:11 ` Michael Ellerman
2024-06-18 7:11 ` Michael Ellerman
2024-06-21 8:12 ` Anjali K
2024-06-21 8:12 ` Anjali K
2024-06-21 11:38 ` Michael Ellerman [this message]
2024-06-21 11:38 ` Michael Ellerman
2024-06-20 17:28 ` Anjali K
2024-06-20 17:28 ` Anjali K
2024-06-20 18:59 ` Kees Cook
2024-06-20 18:59 ` Kees Cook
2024-06-24 12:30 ` Michael Ellerman
2024-06-24 12:30 ` Michael Ellerman
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