Paul,

I think care is needed related to the "key instance counter".  If defaults always go to zero, then won't we have instances where the key instance counter will not be good enough to distinguish that a change has occurred.  e.g., key instance counter = 1 and is saved for the lock comparison.  The encryption parameters are set to default.  A new I_T nexus or the same creates new encryption parameters.  The key instance counter =1.  This is the same as the previous set, but has changed.

If the key instance counter does not reset to zero when encryption is disabled, then it continues to count and there is no issue with the same value.  The only concern is for RESETs.  In those cases, everything in the LUN changes and the 6/2900 UA occurs which should trigger basic setups to occur.  Though the lock is trying to address lack of visibility to UA's.

Thanks,

Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-2869 / 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt@us.ibm.com
http://www-03.ibm.com/servers/storage/


"Entzel, Paul" <Paul.Entzel@lsi.com>

04/02/2008 07:41 AM

To
Kevin D Butt/Tucson/IBM@IBMUS
cc
"Ballard, Curtis C \(StorageWorks\)" <curtis.ballard@hp.com>, <owner-t10@t10.org>, <t10@t10.org>
Subject
RE: SSC-3: Late Letter Ballot comment





Kevin,
I think you have pointed out a gaping hole in this part of the standard.  There is no definition for the phrase "default data encryption parameters" anywhere in SSC-3.  I always assumed we had one, since we used the term several times in the standard, but I went to look for it as a rebuttal to your email, and it's not there.  This is probably a common problem when creating such a large proposal, if you remember the final version of the proposal that added encryption control to SSC-3 was about 30 pages long.  Anyway, it might help you understand my point of view if I were to describe my definition of the "default data encryption parameters".  The default data encryption parameters are a statically defined set of data encryption parameters as defined in 4.2.21.8 with the encryption mode parameter set to DISABLE, the encryption mode parameter set to DISABLE, and the key instance counter parameter set to 0.  All other fields are undefined.  The last sentence fixes the problem of what to put in the I and the T parameters, and more important, what to put in the key scope parameter.  In my opinion, it does not matter what you put in these parameters, since the parameter set is statically defined, that is, it exists from reset and never gets release or reallocated.  It is shared between I_T nexuses, like the ALL I_T NEXUS scope parameters set, but exists even when a valid ALL I_T NEXUS scope set of data encryption parameters exists.  I like this concept because it gives you a place to park any I_T nexuses that set a LOCAL scope set of data encryption parameters that specify DISABLE/DISABLE without burning a full set of unique data encryption parameters for them.
 
However, another way to fix this problem would be to remove this term and add a couple of new rules to the ALL I_T NEXUS scope set of data encryption parameters.  In the original proposal, support for the the ALL I_T NEXUS scope was not mandatory, so this would have not fixed the problem.  But in SSC-3 now, support for this scope is mandatory and in 4.2.21.8 there is a paragraph that states:
 
A device server shall support an encryption key scope value of ALL I_T NEXUS and the physical device shall have resources to save one set of data encryption parameters with this scope.
 
Since the ALL I_T NEXUS scope set of data encryption parameters is statically allocated, there's no reason rules can't be created for the default settings to be used on power-up and when no key of this scope is defined.  How about if this set of data encryption parameters is defined to default to DISABLE for the encryption mode and decryption mode parameters?  A rule could be added that the ALL I_T NEXUS scope data encryption parameters shall be set to default values when released.  If you did this, then the term "default data encryption parameters" is synonymous with the term "set of data encryption parameters with the scope parameter of ALL I_T NEXUS".  This is true because the default data encryption scope parameter for each I_T nexus is PUBLIC (see 4.2.21.7).  There are a couple of places that state what to do if there is no ALL I_T NEXUS scope data encryption parameters that would need to change, since there always will be one.
 
Either of these changes will fix the problem of what key instance counter value to lock to.
 
As for the UML, I am far from an expert and am a little confused about your use of DS(1).  However, the information saved per I_T nexus is defined in 4.2.21.7 and the information saved per data encryption parameters set is defined in 4.2.21.8, and they are significantly different.  We've already discussed that there is not always a one to one relationship between I_T nexus and data encryption parameters, and that not every I_T nexus will have a set of data encryption parameters that is "owns".  However, if you agree with the concepts I mentioned above, there is one and only one set of data encryption parameters associated with each I_T nexus at all times (a LOCAL set, the ALL I_T NEXUS set, or the default set (if this concept remains)).
 
I hope this helps,
Paul Entzel

From: Kevin D Butt [mailto:kdbutt@us.ibm.com]
Sent: Tuesday, April 01, 2008 5:36 PM
To: Entzel, Paul
Cc: Ballard, Curtis C (StorageWorks); owner-t10@t10.org; t10@t10.org
Subject: RE: SSC-3: Late Letter Ballot comment

Paul,

I see. I think I agree with everything you have said.

My review has uncovered the need to add a statement that the "data encryption scope" field is set to PUBLIC when the device server processes a set data encryption page with the SCOPE field set to PUBLIC.

How "key scope" is set to LOCAL is not covered.

To summarize in a UMLish view what we discussed:
a.        DS (1)-------(0..1) set of data encryption parameters with key scope=ALL I_T NEXUS
b.        DS (1)-------(0..n) set of data encryption parameters with key scope=LOCAL [there is one for every I_T nexus that has a data encryption scope=LOCAL]
c.        DS (1)-------(1..n) saved information per I_T nexus (4.2.21.7) [there is one for every I_T nexus in existence]

a) and b) are constrained such that only one can exist at a time for a specific I_T nexus.

When the data encryption scope=PUBLIC for an I_T nexus, then that I_T nexus uses the data encryption parameters in a) if they exist.

Now my concern is, what is the proper behavior in this scenario:
I_T nexus A sends a SPOUT command to create a set of data encryption parameters with a scope of ALL I_T_NEXUS but does not set the LOCK bit, then I_T nexus B sends a SPOUT command with a scope of PUBLIC with the LOCK bit set to 1, the ENCRYPTION MODE field set to DISABLE and DECRYPTION MODE field set to DISABLE or RAW.

According to 4.2.21.6 If the encryption/decryption modes are set to DISABLE, then "release any resources that it had allocated to store data encryption parameters for the I_T nexus associated with the SECURITY PROTOCOL OUT command and shall change the contents of all memory containing a key value associated with the data encryption parameters that are released;"

I believe the intent would be to lock B to the encryption parameters for the ALL I_T NEXUS (i.e., established by A).  
But if there were no A, then what would happen?  There are no encryption parameters (..shall release any resources that it had allocated to store data encryption parameters..) so there is no "key instance counter".

I think it would break if the key instance counter were released.  Instead the key instance counter should be incremented.  This needs to be corrected.

Thanks,

Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-2869 / 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt@us.ibm.com
http://www-03.ibm.com/servers/storage/

"Entzel, Paul" <Paul.Entzel@lsi.com>

04/01/2008 02:48 PM


To
Kevin D Butt/Tucson/IBM@IBMUS
cc
"Ballard, Curtis C \(StorageWorks\)" <curtis.ballard@hp.com>, <owner-t10@t10.org>, <t10@t10.org>
Subject
RE: SSC-3: Late Letter Ballot comment







Kevin,
The device server should not establish a set of data encryption parameters for an I_T nexus that issues a SPOUT command that sends a Set Data Encryption page with the SCOPE field set to PUBLIC.  See the third paragraph in 4.2.21.7.  There is no question that this could be made clearer both in the model clause and in table 142.
Paul

From: Kevin D Butt [mailto:kdbutt@us.ibm.com]
Sent: Tuesday, April 01, 2008 1:48 PM
To: Entzel, Paul
Cc: Ballard, Curtis C (StorageWorks); owner-t10@t10.org; t10@t10.org
Subject: RE: SSC-3: Late Letter Ballot comment


My comments below <<kdbutt>>

Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-2869 / 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt@us.ibm.com
http://www-03.ibm.com/servers/storage/
"Entzel, Paul" <Paul.Entzel@lsi.com>
Sent by: owner-t10@t10.org

04/01/2008 06:51 AM


To
Kevin D Butt/Tucson/IBM@IBMUS
cc
"Ballard, Curtis C \(StorageWorks\)" <curtis.ballard@hp.com>, <t10@t10.org>
Subject
RE: SSC-3: Late Letter Ballot comment






Kevin,
Comments below.
Paul Entzel

From: Kevin D Butt [mailto:kdbutt@us.ibm.com]
Sent: Monday, March 31, 2008 5:21 PM
To: Entzel, Paul
Cc: Ballard, Curtis C (StorageWorks); owner-t10@t10.org; t10@t10.org
Subject: RE: SSC-3: Late Letter Ballot comment


Paul,

Just to be clear, the LOCK bit is only associated with the specific I_T nexus on which the SPOUT command was received with the LOCK bit set.  
[Paul Entzel] Yes.
In your example A is not locked to the parameters (the parameters being those set for I_T nexus A) but B is locked to the parameters (those parameters set for I_T nexus B - which are different parameters than those that are set for I_T nexus A).
[Paul Entzel] The fist half of this sentence is correct, but the parenthetical part is not.  In my example, initiator A established a set of shared data encryption parameters using the ALL I_T NEXUS scope.  Initiator B did not establish a set of parameters, but instead created an association with the shared data encryption parameters and locked itself to this set of parameters by using the PUBLIC scope and the LOCK bit.  The two initiators are associated with the same set of data encryption parameters.  
<<kdbutt: Yes, because B used PUBLIC it refers to the ALL I_T NEXUS parameters.  I missed this.>>

The key point here is that the encryption parameters are set per I_T nexus.  
[Paul Entzel]  If this were true, Curtis' external encryption control will never work. If the scope is LOCAL, then this is true.  If the scope is ALL I_T NEXUS, then the data encryption parameters are shared between the I_T nexus that set them and all I_T nexuses that have been configured with a scope of PUBLIC.
<<kdbutt: I agree>>
Any changes that occur on other I_T nexuses do not change the parameters in another I_T nexus.  
[Paul Entzel] If the SCOPE field is LOCAL in page that establishes a set of data encryption parameters, then this is generally true.  To accommodate designs with limited resources for storage of data encryption parameters (particularly keys), the standard allows for the device to release a set of data encryption parameters for anther I_T nexus when they needed to establish a new set of data encryption parameters for a different I_T nexus.  This feature is optional.  See the second paragraph in 4.2.21.8.  Remember, the data encryption parameters are not IN the I_T nexus, they are in the physical device.  They are owned by an I_T nexus and possible shared with other I_T nexuses.
<<kdbutt: I agree>>
This means the LOCK bit only helps the I_T nexus that set the encryption parameters with the LOCK bit set.
[Paul Entzel]  The LOCK bit only applies to an I_T nexus that set the bit in the Set Data Encryption Parameters page in the last SPOUT command that sent this page.  
<<kdbutt: I agree>>
This page may not have established a set of data encryption parameters, it may have also had the SCOPE field set to PUBLIC which means that the I_T nexus is locked to the current set of ALL I_T NEXUS data encryption parameters, if one exists.  
<<kdbutt: In this case there is a set of data encryption parameters.  The key scope and the encryption mode and decryption mode are all part of the data encryption parameters.  This means that when the SCOPE is set to PUBLIC, that there exists data encryption parameters associated with this I_T nexus, but it also means that this I_T nexus is to use the data encryption parameters that are set with a SCOPE of ALL I_T NEXUS.  This means that this I_T nexus has two sets of data encryption parameters - the one whose scope is PUBLIC and the one whose scope is ALL I_T NEXUS.
In 4.2.21.7 paragraphs 3,4,5, and 6 the scope is referred to as being saved by I_T nexus.  But in 4.2.21.8 key scope is listed as part of the data encryption parameters.  How can data encryption parameters not be by I_T nexus yet some of its members are by I_T nexus.  I think this shows that the requirements are not clear in SSC-3.  I agree that data encryption parameters should be a global thing, but some of what we list as data encryption parameters are said to be for a specific I_T nexus.
Perhaps I am looking at this wrong, but it seems to be lacking a complete or concise description and we have placed certain parameters in the data encryption parameters when we should not have.>>
If not, it is locked to the default set of data encryption parameters (DISABLED/DISABLED).  
The point behind the LOCK bit was to provide a method to prevent the device from writing data if the data encryption parameters had changed since the last time the application client configured them without the application client having a chance to fix them again, even in an environment where UAs don't make it to the proper layer to fix the problem.  If Gideon is listening, this is the place where he jumps in and claims that the protection is too weak and so it is worthless, but it is what we have.
<<kdbutt: I agree with the point of the LOCK>>

Thanks,

Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-2869 / 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt@us.ibm.com
http://www-03.ibm.com/servers/storage/
"Entzel, Paul" <Paul.Entzel@lsi.com>
Sent by: owner-t10@t10.org

03/31/2008 02:55 PM


To
"Ballard, Curtis C \(StorageWorks\)" <curtis.ballard@hp.com>, <t10@t10.org>
cc
Subject
RE: SSC-3: Late Letter Ballot comment







Hello Curtis,

The concept of LOCK was to allow an I_T nexus to create a fixed association with a particular set of data encryption parameters at a specific generation (key instance counter).  This association is saved with the I_T nexus (see subclause 4.2.21.7) not with the set of data encryption parameters because more than one I_T nexus can be associated with a set of data encryption parameters (one as the creator, others using the PUBLIC scope).  It was not an oversight to not include the lock bit in the data encryption parameters structure, it doesn't belong there.  Consider the example where I_T nexus A sends a SPOUT command to create a set of data encryption parameters with a scope of ALL I_T_NEXUS but does not set the LOCK bit, then I_T nexus B sends a SPOUT command with a scope of PUBLIC with the LOCK bit set to 1.  In this example, A is not locked to the parameters but B is.  What would you put in the lock parameter if it was part of the set of data encryption parameters?

You may want to consider fixing the problem by introducing the concept of a master key instance counter in 4.2.41.10 that is not associated with any set of data encryption parameters.  It would be incremented and inserted into the set of data encryption parameters each time one is created.  You would also need to modify the test in 4.2.21.11 such that a lock violation occurs if the I_T nexus is locked and the data encryption parameters have been released.

Paul Entzel

From: owner-t10@t10.org [mailto:owner-t10@t10.org] On Behalf Of Ballard, Curtis C (StorageWorks)
Sent: Monday, March 31, 2008 2:51 PM
To: 't10@t10.org'
Subject: RE: SSC-3: Late Letter Ballot comment

Kevin,

I looked into this a bit and came to a different conclusion.

You reference section 4.2.21.6 on Managing keys within the device server and the section on when to release a set of data encryption parameters which does not discuss turning off encryption.

I believe the section we need to reference is a little further into 4.2.21.6 at that start of document page 56 in SSC3r04a.pdf where it discusses what to do when both the ENCRYPTION MODE and the DECRYPTION MODE are set to DISABLE which is the encryption off condition.

"If a device server processes a Set Data Encryption page with the ENCRYPTION MODE field set to DISABLE and DECRYPTION MODE field set to DISABLE or RAW, the physical device shall:


a)release any resources that it had allocated to store data encryption parameters for the I_T nexus associated with the SECURITY PROTOCOL OUT command and shall change the contents of all memory containing a key value associated with the data encryption parameters that are released; and

b)establish a unit attention condition . . ."

The statement "data encryption parameters" was referenced to 4.2.21.8 earlier in that clause so if we follow that reference we find that virtually all of the settings that a host can establish are included in the data encryption parameters including the key instance counter which is tied to locking.  When both modes are set to DISABLED which is what has to be done to turn encryption off, then everything in the set of data encryption parameters is released so all of those values are gone.  If the counter is gone along with all the other parameters I don't see how the parameters can possibly continue to be associated with that I_T nexus.

According to my notes we discussed at the last SSC-3 meeting that "LOCK" should also be included in the data encryption parameters but wasn't due to an oversight.  If it had been then it would be clear that "LOCK" is gone when the encryption parameters are released.

I'm concerned that this behavior seems to be inconsistent with the introduction to 4.2.21.11 which discusses exactly the case of resources being released and the UA not detected and suggests that LOCK solves the issue.

If the intent is that LOCK persist when the rest of the parameters are released then I don't think the change is as simple as you suggest.  I think that we would need to modify 4.2.21.6 to indicate that the key instance counter is not released with the rest of the parameters if LOCK is set to one, but instead is incremented.  That way the test described in the section on locking where a changed key instance counter triggers the CHECK CONDITION will still work.  We might also have to modify some text describing releasing resources when limited resources are exhausted to make it clear that parameters containing a LOCK bit set to one can't be released (I have some concerns with whether that can be required).  There might also be other sections that talking about releasing parameters that would need examined.

This one looks to me like it's going to take a proposal to address.

Curtis Ballard
Hewlett Packard









From: owner-t10@t10.org [mailto:owner-t10@t10.org] On Behalf Of Kevin D Butt
Sent: 20 March 2008 21:48
To: t10@t10.org
Subject: SSC-3: Late Letter Ballot comment

I received communication from an ISV today related to Encryption mode locking (4.2.21.11).  They were unable to determine if the locking applied when the data encryption parameters were set such that encryption/decryption is turned off.  In a close reading this clause refers to "...locked to that set of data encryption parameters and key instance counter value until a hard reset condition occurs or another [SPOUT command is received]"

In 4.2.21.6 Managing keys within the physical device, where it describes when to release a set of data encryption parameters, there is no mention of turning off encryption.  Therefore, the locking does apply to the saved set of encryption parameters even when encryption is turned off.  This is indeed the desired behavior.  However, it is not clear to the casual or novice standards reader that this is the case.

Proposed Solution (Editorial):
In 4.2.21.11, p2, add a new sentence after s1:
The LOCK bit in the Set Data Encryption page is set to one to lock the I_T nexus that issued the SECURITY PROTOCOL OUT command to the set of data encryption parameters established at the completion of the processing of the command.  A set of data encryption parameters are established and locked even if the ENCRYPTION MODE is set to DISABLE and the DECRYPTION MODE is set to DISABLE.

Thanks,

Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-2869 / 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt@us.ibm.com
http://www-03.ibm.com/servers/storage/