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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: "Ayoun, Serge" <serge.ayoun@intel.com>,
	"linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>
Cc: "Christopherson, Sean J" <sean.j.christopherson@intel.com>
Subject: Re: [PATCH 4/5] x86/sgx: Validate TCS permssions in sgx_validate_secinfo()
Date: Thu, 22 Aug 2019 19:59:34 +0300	[thread overview]
Message-ID: <6a5fb735e795c25ceb075d4a6f4db20653b731af.camel@linux.intel.com> (raw)
In-Reply-To: <fa7ef5b767298ac19857d8342a8eca65e31eb843.camel@linux.intel.com>

On Thu, 2019-08-22 at 19:46 +0300, Jarkko Sakkinen wrote:
> On Thu, 2019-08-22 at 11:33 +0000, Ayoun, Serge wrote:
> > Also replying to Sean.
> > Sean is right that never mind the value in secsinfo->flags, HW will reset RWX
> > For TCS pages.
> > So basically you may not enforce and and could not check those but... The signature depends
> > On those flags, so if you put a non-zero flag value, eadd will pass but if you
> > compute the signature according to this non zero value then you will have
> > a delta between ur signature and HW's signature: einit will fail.
> > So this is tricky and more a usability issue.
> > I vote for checking the flag is zeroed.
> 
> As I responded to Sean that as long as the ioctl does not adjust
> prot bits I'm cool with any sane solution. What do you think of
> requiring at minimum RW?
> 
> Doing that kind of adjusting is just doing fixup's for corrupted
> data from the user space.

Kind of missed your comment about EINIT in rush! A valid point
and good catch.

I still think my 2nd proposal would be more appropriate than this
patch. Signatures will work and we don't need special cases anywhere.

/Jarkko


  reply	other threads:[~2019-08-22 16:59 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-19 15:25 [PATCH 0/5] x86/sgx: Improve permission handing Jarkko Sakkinen
2019-08-19 15:25 ` [PATCH 1/5] x86/sgx: Document permission handling better Jarkko Sakkinen
2019-08-22  3:43   ` Sean Christopherson
2019-08-22 16:04     ` Jarkko Sakkinen
2019-08-19 15:25 ` [PATCH 2/5] x86/sgx: Use memchr_inv() in sgx_validate_secinfo() Jarkko Sakkinen
2019-08-22  3:47   ` Sean Christopherson
2019-08-22 16:20     ` Jarkko Sakkinen
2019-08-19 15:25 ` [PATCH 3/5] x86/sgx: Make sgx_validate_secinfo() more readable Jarkko Sakkinen
2019-08-22  3:48   ` Sean Christopherson
2019-08-22 16:26     ` Jarkko Sakkinen
2019-08-22 10:39   ` Ayoun, Serge
2019-08-22 16:45     ` Jarkko Sakkinen
2019-08-19 15:25 ` [PATCH 4/5] x86/sgx: Validate TCS permssions in sgx_validate_secinfo() Jarkko Sakkinen
2019-08-21 18:45   ` Jarkko Sakkinen
2019-08-22 11:33     ` Ayoun, Serge
2019-08-22 14:27       ` Sean Christopherson
2019-08-22 16:46       ` Jarkko Sakkinen
2019-08-22 16:59         ` Jarkko Sakkinen [this message]
2019-08-22  3:55   ` Sean Christopherson
2019-08-22 16:31     ` Jarkko Sakkinen
2019-08-22 16:34       ` Sean Christopherson
2019-08-23  0:39         ` Jarkko Sakkinen
2019-08-23  0:57           ` Jarkko Sakkinen
2019-08-23  2:05             ` Sean Christopherson
2019-08-23 13:41               ` Jarkko Sakkinen
2019-08-22 16:38       ` Jarkko Sakkinen
2019-08-19 15:25 ` [PATCH 5/5] x86/sgx: Rename vm_prot_bits as max_vm_flags Jarkko Sakkinen
2019-08-22  4:00   ` Sean Christopherson
2019-08-22 16:43     ` Jarkko Sakkinen

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