From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Michael Ellerman <mpe@ellerman.id.au>, linuxppc-dev@ozlabs.org
Subject: Re: [v6,01/10] powerpc/powernv/idle: Restore IAMR after idle
Date: Mon, 22 Apr 2019 00:19:14 +1000 (AEST) [thread overview]
Message-ID: <44nBfV60dTz9sNF@ozlabs.org> (raw)
In-Reply-To: <20190418065125.2687-1-mpe@ellerman.id.au>
On Thu, 2019-04-18 at 06:51:16 UTC, Michael Ellerman wrote:
> From: Russell Currey <ruscur@russell.cc>
>
> Without restoring the IAMR after idle, execution prevention on POWER9
> with Radix MMU is overwritten and the kernel can freely execute
> userspace without faulting.
>
> This is necessary when returning from any stop state that modifies
> user state, as well as hypervisor state.
>
> To test how this fails without this patch, load the lkdtm driver and
> do the following:
>
> $ echo EXEC_USERSPACE > /sys/kernel/debug/provoke-crash/DIRECT
>
> which won't fault, then boot the kernel with powersave=off, where it
> will fault. Applying this patch will fix this.
>
> Fixes: 3b10d0095a1e ("powerpc/mm/radix: Prevent kernel execution of user space")
> Cc: stable@vger.kernel.org # v4.10+
> Signed-off-by: Russell Currey <ruscur@russell.cc>
> Reviewed-by: Akshay Adiga <akshay.adiga@linux.vnet.ibm.com>
> Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Series applied to powerpc next.
https://git.kernel.org/powerpc/c/a3f3072db6cad40895c585dce65e36aa
cheers
prev parent reply other threads:[~2019-04-21 15:07 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-18 6:51 [PATCH v6 01/10] powerpc/powernv/idle: Restore IAMR after idle Michael Ellerman
2019-04-18 6:51 ` [PATCH v6 02/10] powerpc/powernv/idle: Restore AMR/UAMOR/AMOR " Michael Ellerman
2019-04-18 6:51 ` [PATCH v6 03/10] powerpc: Add framework for Kernel Userspace Protection Michael Ellerman
2019-04-18 6:51 ` [PATCH v6 04/10] powerpc: Add skeleton for Kernel Userspace Execution Prevention Michael Ellerman
2019-04-18 6:51 ` [PATCH v6 05/10] powerpc: Add a framework for Kernel Userspace Access Protection Michael Ellerman
2019-04-18 6:51 ` [PATCH v6 06/10] powerpc/64: Setup KUP on secondary CPUs Michael Ellerman
2019-04-24 6:03 ` Christophe Leroy
2019-04-18 6:51 ` [PATCH v6 07/10] powerpc/mm/radix: Use KUEP API for Radix MMU Michael Ellerman
2019-04-18 6:51 ` [PATCH v6 08/10] powerpc/lib: Refactor __patch_instruction() to use __put_user_asm() Michael Ellerman
2019-04-18 6:51 ` [PATCH v6 09/10] powerpc/64s: Implement KUAP for Radix MMU Michael Ellerman
2020-04-17 10:10 ` Christophe Leroy
2020-04-17 10:39 ` Nicholas Piggin
2020-04-17 12:02 ` Christophe Leroy
2019-04-18 6:51 ` [PATCH v6 10/10] powerpc/mm: Detect bad KUAP faults Michael Ellerman
2019-04-21 14:19 ` Michael Ellerman [this message]
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