From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: linux-sgx@vger.kernel.org
Subject: Re: [PATCH v2 2/5] x86/sgx: Reject concurrent ioctls on single enclave
Date: Thu, 29 Aug 2019 21:14:38 +0300 [thread overview]
Message-ID: <20190829181438.oxix5d7qfgru7bd7@linux.intel.com> (raw)
In-Reply-To: <20190829160001.GD26580@linux.intel.com>
On Thu, Aug 29, 2019 at 09:00:01AM -0700, Sean Christopherson wrote:
> > #PF handler should be good as it has this conditional:
> >
> > flags = atomic_read(&encl->flags);
> >
> > if ((flags & SGX_ENCL_DEAD) || !(flags & SGX_ENCL_INITIALIZED))
> > return ERR_PTR(-EFAULT);
> >
> > What about the reclaimer?
>
> Can you elaborate? I'm not sure what you're asking.
I'm thinking of a race between list_add() in the ioctl and
list_move_tail() in the reclaimer.
A quick way to fix this would be move sgx_alloc_va_page() from
sgx_encl_grow() and return NULL if a new allocation is required.
In the ioctl you can then allocate the page before taking locks and
do "list_add(&va_page->list, &encl->va_pages);" behind the locks.
/Jarkko
next prev parent reply other threads:[~2019-08-29 18:14 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-27 19:27 [PATCH v2 0/5] x86/sgx: Fix lock ordering bug w/ EADD Sean Christopherson
2019-08-27 19:27 ` [PATCH v2 1/5] x86/sgx: Convert encl->flags from an unsigned int to an atomic Sean Christopherson
2019-08-29 13:09 ` Jarkko Sakkinen
2019-08-29 15:59 ` Sean Christopherson
2019-08-29 18:01 ` Jarkko Sakkinen
2019-08-30 0:02 ` Sean Christopherson
2019-08-27 19:27 ` [PATCH v2 2/5] x86/sgx: Reject concurrent ioctls on single enclave Sean Christopherson
2019-08-29 13:15 ` Jarkko Sakkinen
2019-08-29 16:00 ` Sean Christopherson
2019-08-29 18:14 ` Jarkko Sakkinen [this message]
2019-08-29 18:43 ` Sean Christopherson
2019-08-29 22:22 ` Jarkko Sakkinen
2019-08-27 19:27 ` [PATCH v2 3/5] x86/sgx: Take encl->lock inside of mm->mmap_sem for EADD Sean Christopherson
2019-08-27 19:27 ` [PATCH v2 4/5] x86/sgx: Reject all ioctls on dead enclaves Sean Christopherson
2019-08-27 19:27 ` [PATCH v2 5/5] x86/sgx: Destroy the enclave if EEXTEND fails Sean Christopherson
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