From: Borislav Petkov <bp@alien8.de>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: x86@kernel.org, linux-sgx@vger.kernel.org,
linux-kernel@vger.kernel.org,
Sean Christopherson <sean.j.christopherson@intel.com>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Matthew Wilcox <willy@infradead.org>,
Jethro Beekman <jethro@fortanix.com>,
Darren Kenny <darren.kenny@oracle.com>,
andriy.shevchenko@linux.intel.com, asapek@google.com,
cedric.xing@intel.com, chenalexchen@google.com,
conradparker@google.com, cyhanish@google.com,
dave.hansen@intel.com, haitao.huang@intel.com,
kai.huang@intel.com, kai.svahn@intel.com, kmoy@google.com,
ludloff@google.com, luto@kernel.org, nhorman@redhat.com,
npmccallum@redhat.com, puiterwijk@redhat.com,
rientjes@google.com, tglx@linutronix.de, yaozhangx@google.com,
mikko.ylinen@intel.com
Subject: Re: [PATCH v40 10/24] mm: Add 'mprotect' hook to struct vm_operations_struct
Date: Thu, 5 Nov 2020 17:04:24 +0100 [thread overview]
Message-ID: <20201105160424.GC25636@zn.tnic> (raw)
In-Reply-To: <20201104145430.300542-11-jarkko.sakkinen@linux.intel.com>
On Wed, Nov 04, 2020 at 04:54:16PM +0200, Jarkko Sakkinen wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
>
> Background
> ==========
>
> 1. SGX enclave pages are populated with data by copying from normal memory
> via ioctl() (SGX_IOC_ENCLAVE_ADD_PAGES), which will be added later in
> this series.
> 2. It is desirable to be able to restrict those normal memory data sources.
> For instance, to ensure that the source data is executable before
> copying data to an executable enclave page.
> 3. Enclave page permissions are dynamic (just like normal permissions) and
> can be adjusted at runtime with mprotect().
>
> This creates a problem because the original data source may have long since
> vanished at the time when enclave page permissions are established (mmap()
> or mprotect()).
>
> The solution (elsewhere in this series) is to force enclaves creators to
> declare their paging permission *intent* up front to the ioctl(). This
> intent can me immediately compared to the source data’s mapping and
> rejected if necessary.
>
> The “intent” is also stashed off for later comparison with enclave
> PTEs. This ensures that any future mmap()/mprotect() operations
> performed by the enclave creator or done on behalf of the enclave
> can be compared with the earlier declared permissions.
>
> Problem
> =======
>
> There is an existing mmap() hook which allows SGX to perform this
> permission comparison at mmap() time. However, there is no corresponding
> ->mprotect() hook.
>
> Solution
> ========
>
> Add a vm_ops->mprotect() hook so that mprotect() operations which are
> inconsistent with any page's stashed intent can be rejected by the driver.
>
> Cc: linux-mm@kvack.org
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Matthew Wilcox <willy@infradead.org>
> Acked-by: Jethro Beekman <jethro@fortanix.com>
> Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Co-developed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
> include/linux/mm.h | 3 +++
> mm/mprotect.c | 5 ++++-
> 2 files changed, 7 insertions(+), 1 deletion(-)
This needs an ACK from an mm person.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2020-11-05 16:04 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20201104145430.300542-1-jarkko.sakkinen@linux.intel.com>
2020-11-04 14:54 ` [PATCH v40 10/24] mm: Add 'mprotect' hook to struct vm_operations_struct Jarkko Sakkinen
2020-11-05 16:04 ` Borislav Petkov [this message]
2020-11-05 17:33 ` Dave Hansen
2020-11-06 10:04 ` Mel Gorman
2020-11-06 16:51 ` Jarkko Sakkinen
2020-11-06 20:37 ` Borislav Petkov
2020-11-06 22:04 ` Jarkko Sakkinen
2020-11-06 22:31 ` Borislav Petkov
2020-11-06 17:43 ` Dr. Greg
2020-11-06 17:54 ` Dave Hansen
2020-11-07 15:09 ` Dr. Greg
2020-11-07 19:16 ` Dave Hansen
2020-11-12 20:58 ` Dr. Greg
2020-11-12 21:31 ` Dave Hansen
2020-11-12 22:41 ` Andy Lutomirski
2020-11-16 18:00 ` Dr. Greg
2020-11-19 1:39 ` Haitao Huang
2020-11-20 17:31 ` Dr. Greg
2020-11-15 18:59 ` Dr. Greg
2020-11-06 21:13 ` Matthew Wilcox
2020-11-06 21:23 ` Dave Hansen
2020-11-07 15:27 ` Dr. Greg
2020-11-04 14:54 ` [PATCH v40 11/24] x86/sgx: Add SGX misc driver interface Jarkko Sakkinen
[not found] ` <20201105011043.GA700495@kernel.org>
[not found] ` <20201105011615.GA701257@kernel.org>
2020-11-05 16:05 ` Borislav Petkov
2020-11-05 17:57 ` Jarkko Sakkinen
2020-11-05 18:10 ` Borislav Petkov
2020-11-06 16:07 ` Jarkko Sakkinen
2020-11-06 17:09 ` Borislav Petkov
2020-11-06 22:01 ` Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 21/24] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-11-08 3:56 ` Hillf Danton
2020-11-09 19:59 ` Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 22/24] x86/sgx: Add ptrace() support for the SGX driver Jarkko Sakkinen
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