From: Michael Ellerman <mpe@ellerman.id.au>
To: Christophe Leroy <christophe.leroy@c-s.fr>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
ruscur@russell.cc
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 10/10] powerpc/32s: Implement Kernel Userspace Access Protection
Date: Thu, 18 Apr 2019 16:55:30 +1000 [thread overview]
Message-ID: <87ftqfu7j1.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <a2847248a92cb1641b1740fa121c5a30593ae662.1552292207.git.christophe.leroy@c-s.fr>
Christophe Leroy <christophe.leroy@c-s.fr> writes:
> diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h
> index 5f97c742ca71..b3560b2de435 100644
> --- a/arch/powerpc/include/asm/book3s/32/kup.h
> +++ b/arch/powerpc/include/asm/book3s/32/kup.h
> @@ -37,6 +37,113 @@
...
> +
> +static inline void allow_user_access(void __user *to, const void __user *from, u32 size)
> +{
> + u32 addr = (__force u32)to;
> + u32 end = min(addr + size, TASK_SIZE);
> +
> + if (!addr || addr >= TASK_SIZE || !size)
> + return;
> +
> + current->thread.kuap = (addr & 0xf0000000) | ((((end - 1) >> 28) + 1) & 0xf);
> + kuap_update_sr(mfsrin(addr) & ~SR_KS, addr, end); /* Clear Ks */
> +}
When rebasing on my v6 I changed the above to:
static inline void allow_user_access(void __user *to, const void __user *from, u32 size)
{
u32 addr, end;
if (__builtin_constant_p(to) && to == NULL)
return;
addr = (__force u32)to;
if (!addr || addr >= TASK_SIZE || !size)
return;
end = min(addr + size, TASK_SIZE);
current->thread.kuap = (addr & 0xf0000000) | ((((end - 1) >> 28) + 1) & 0xf);
kuap_update_sr(mfsrin(addr) & ~SR_KS, addr, end); /* Clear Ks */
}
Which I think achieves the same result. It does boot :)
> +
> +static inline void prevent_user_access(void __user *to, const void __user *from, u32 size)
> +{
> + u32 addr = (__force u32)to;
> + u32 end = min(addr + size, TASK_SIZE);
> +
> + if (!addr || addr >= TASK_SIZE || !size)
> + return;
> +
> + current->thread.kuap = 0;
> + kuap_update_sr(mfsrin(addr) | SR_KS, addr, end); /* set Ks */
> +}
> +
> +static inline void allow_read_from_user(const void __user *from, unsigned long size)
> +{
> +}
And I dropped that.
cheers
next prev parent reply other threads:[~2019-04-18 6:55 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-11 8:30 [PATCH v2 00/10] Kernel Userspace protection for PPC32 Christophe Leroy
2019-03-11 8:30 ` [PATCH v2 01/10] powerpc/6xx: fix setup and use of SPRN_SPRG_PGDIR for hash32 Christophe Leroy
2019-03-20 13:04 ` [v2, " Michael Ellerman
2019-03-11 8:30 ` [PATCH v2 02/10] powerpc/mm: Detect bad KUAP faults (Squash of v5 series) Christophe Leroy
2019-03-11 8:30 ` [PATCH v2 03/10] powerpc/32: Remove MSR_PR test when returning from syscall Christophe Leroy
2019-04-21 14:18 ` [v2, " Michael Ellerman
2019-03-11 8:30 ` [PATCH v2 04/10] powerpc/32: Prepare for Kernel Userspace Access Protection Christophe Leroy
2019-03-11 8:30 ` [PATCH v2 05/10] powerpc/8xx: Only define APG0 and APG1 Christophe Leroy
2019-03-11 8:30 ` [PATCH v2 06/10] powerpc/8xx: Add Kernel Userspace Execution Prevention Christophe Leroy
2019-03-11 8:30 ` [PATCH v2 07/10] powerpc/8xx: Add Kernel Userspace Access Protection Christophe Leroy
2019-04-18 6:53 ` Michael Ellerman
2019-03-11 8:30 ` [PATCH v2 08/10] powerpc/32s: Implement Kernel Userspace Execution Prevention Christophe Leroy
2019-03-11 8:30 ` [PATCH v2 09/10] powerpc/32s: Prepare Kernel Userspace Access Protection Christophe Leroy
2019-03-11 8:30 ` [PATCH v2 10/10] powerpc/32s: Implement " Christophe Leroy
2019-04-18 6:55 ` Michael Ellerman [this message]
2019-04-23 9:26 ` Christophe Leroy
2020-01-21 17:22 ` GCC bug ? " Christophe Leroy
2020-01-21 19:55 ` Segher Boessenkool
2020-01-22 6:52 ` Christophe Leroy
2020-01-22 13:36 ` Segher Boessenkool
2020-01-22 14:45 ` Christophe Leroy
2020-01-22 6:57 ` Christophe Leroy
2020-01-22 13:18 ` Segher Boessenkool
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=87ftqfu7j1.fsf@concordia.ellerman.id.au \
--to=mpe@ellerman.id.au \
--cc=benh@kernel.crashing.org \
--cc=christophe.leroy@c-s.fr \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=paulus@samba.org \
--cc=ruscur@russell.cc \
/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).