Oops, this reply was supposed to be a "reply list" rather than a
"reply".
I've incorporated most of your feedback into the Change page now.
Thanks.
bob
On 5/29/20 12:23 AM, Zbigniew Jędrzejewski-Szmek wrote:
On Thu, May 28, 2020 at 03:46:25PM -0400, Ben Cotton wrote:Thanks, If you don't program in C, the change has no affect on you. It's a source level incompatibility, not a binary. I'll add that to the description.
https://fedoraproject.org/wiki/Changes/NssGCMParamsWhen I'm reading this description, it feels like it was written by
== Summary ==
Because of changes to the PKCS #11 spec in PKCS #11 v3.0, NSS needs to
change the definition of CK_GCM_PARAMS in a source incompatible way.
Upstream made this change in NSS 3.52.
somebody deep in the subject, but Change pages need to be accessible
to a general audience, even people who don't program in C. They should
be able to get the gist without having to absorb all the details.
Yup, how to adjust is described below. I'm trying to keep the summary short.
It'd help if this summary mentioned that CK_GCM_PARAMS is a struct
definition and that a new field was added (if I got that right) and that
end programs need to adjust by changing how they do [what?].
I need to fix some typos. "must be set correctly" is described below.== Owner ==This part is very hard to grok. Is the capitalized "SPEC" an abbreviation?
* Name: [[User:rrelyea| Bob Relyea]]
* Email: rrelyea@xxxxxxxxxx
== Detailed Description ==
PKCS #11 2.40 had a mismatch between the SPEC and the released header
file for CK_GCM_PARAMS. The latter is controlling. We created or
header based on the former. In PKCS #11 v3.0 the reconciled this, but
it left us with. The new (to NSS) definition has a new field ulIvBits,
which must be set correctly.
One of the sentences ends mid-sentence. Also "must be set correctly"
by whom, how?
It is. change your instances of CK_GCM_PARAMS to CK_GCM_PARAMS_V3
To solve this, the NSS 3.52 headers has both definitions:What does "rename" mean in this context? Based on the earlier text, I
CK_NSS_GCM_PARAMS is the original NSS definition and CK_GCM_PARAMS_V3
is the new (to NSS) definition. CK_GCM_PARAMS takes on one or the
other based on the definition of NSS_PKCS11_2_0_COMPAT.
The current NSS builds in fedora have changes the sense of this
#define to NSS_PKCS11_3_0_STRICT to get the new behavior, and keep the
old behavior by default. NSS builds will automatically switch back to
the upstream default in Fedora 34. None of the changes below actually
requires setting the NSS_PKCS11_3_STRICT define, though doing so can
test that all but option 1 is functioning.
Applications can fix this the following ways:
option 1
#define NSS_PKCS11_2_0_COMPAT 1
or compile with -DNSS_PKCS11_2_0_COMPAT
your app will compile and run using current and older versions of NSS,
but may break on newer tokens that use the new definition (same as the
previous behavior.
---------------------------------------------------------------
option 2
rename CK_GCM_PARAMS to CK_NSS_GCM_PARAMS (this will now require nss
= 3.52 to compile, but won't change based on NSS_PKCS11_2_0_COMPAT).Like option 2 it may break on newer tokens.
thought CK_GCM_PARAMS was a structure...
I guess I could say "see description".------------------------------------------------------------------The text from above starts repeating here?
option 3
rename CK_GCM_PARAMS to CK_GCM_PARAMS_V3 and set ulIvBits to ulIvLen*8.
This will require nss >= 3.52 to compile and to run. Should run on all
run tokens.
-----------------------------------------------------------------
option 4
Move to PK11_AEADOp interface, which all requires nss >= 3.52 to
compile and run, but it's less surprising and the dependency will be
picked up automatically because you are using a new for 3.52
interface.
----------------------------------
Option 4 is the preferred solution. It takes advantage the the PKCS
#11 v3 interface for AES_GCM while removing any PCKS #11 param
structure dependency in the application. It also handles backward
compatibility on older tokens and automatically detects which flavor
of data structure is supported. It also would help with applications
that support two or more of AES_GCM, AES_CCM, and CHACHA_POLY.
== Benefit to Fedora ==
This change will keep fedora with the NSS upstream as well as make
Fedora compliant with the official OASIS PKCS #11 spec.
== Scope ==
* Proposal owners: NSS 3.52 has already had builds made with the
reverse sense. NSS will need to be rebuilt at the start of Fedora 34.
* Other developers: Developers need to choose one of these options by
fedora 34 or their rebuilt packages will fail at runtime.
No, nss 3.52 in fedora has been patched to that the default is to use the old structure, and that version of nss is available on all supported versions of fedora currently. If you rebuild your package now, you will still get the old behavior by default. All the proposed fixes will work with the new 3.52 with patch. The testing section tells how you can make sure the new fixes will work when the patch is removed in fedora 34.
option 1This only applies to packages which use NSS. Maybe first specify a
#define NSS_PKCS11_2_0_COMPAT 1
or compile with -DNSS_PKCS11_2_0_COMPAT
your app will compile and run using current and older versions of NSS,
but may break on newer tokens that use the new definition (same as the
previous behavior.
---------------------------------------------------------------
option 2
rename CK_GCM_PARAMS to CK_NSS_GCM_PARAMS (this will now require nss
= 3.52 to compile, but won't change based on NSS_PKCS11_2_0_COMPAT).Like option 2 it may break on newer tokens.
------------------------------------------------------------------
option 3
rename CK_GCM_PARAMS to CK_GCM_PARAMS_V3 and set ulIvBits to ulIvLen*8.
This will require nss >= 3.52 to compile and to run. Should run on all
run tokens.
-----------------------------------------------------------------
option 4
Move to PK11_AEADOp interface, which all requires nss >= 3.52 to
compile and run, but it's less surprising and the dependency will be
picked up automatically because you are using a new for 3.52
interface.
----------------------------------
Option 4 is the preferred solution. It takes advantage the the PKCS
#11 v3 interface for AES_GCM while removing any PCKS #11 param
structure dependency in the application. It also handles backward
compatibility on older tokens and automatically detects which flavor
of data structure is supported. It also would help with applications
that support two or more of AES_GCM, AES_CCM, and CHACHA_POLY.
* Release engineering: [https://pagure.io/releng/issue/9486 #Releng
issue number 9486]
I believe there is no additional release engineering requirements for
this bug. Only packages which use CK_AES_GCM_PARAMS need action and
the action can happen outside the release process.
* Policies and guidelines: There isn't any policy or guideline
changes needed for this change.
* Trademark approval: N/A (not needed for this Change)
== Upgrade/compatibility impact ==
There is no upgrade impact. There will be a source level
incompatibility on rebuild at fedora 34. This change is to allow a
transition in fedora 33 where source code can be updated in ways that
work in both fedora 33 and fedora 34 after recompile. There are no
binary compatibility issues (old applications compiled with the old
version of nss will continue to work).
== How To Test ==
repoquery line to figure out what packages may be affected because they
build-require nss.
If you could do this and the first step below and figure out how many
packages may be affected (along with a list of maintainers), we'd have
a much better idea of the scope of work.
#. Grep for CK_AES_GCM_PARAMS in our source tree. If it does notWe seem to have a chicken-and-egg problem here: solutions 2-4 require
appear, no further action is needed.
#. If you choose options 2-4, you can do a normal test build and run
your normal tests against any version of nss > 3.52
#. If you think you don't need to make a change, compile your package
with -DNSS_PKCS11_3_0_STRICT and run your normal tests. If everything
works should should not need further action.
#. option 1 would require building NSS without the patch and then
rebuilding with your package. Only use option 1 if you need to build
your package against older versions of nss.
NOTE: The effect of not changing will create a runtime issue where
your AES_GCM call will fail after recompiling.
== User Experience ==
Users who don't build their own packages will see no issues. Users
that build their own packages and use classic NSS AES_GCM will see
runtime failures after a rebuild unless they update their packages.
== Dependencies ==
nss-3.52 or greater.
the new nss, and non-updated packages will not run with the new nss. How do
envision the transition in rawhide? If new nss is pushed first, dependent
packages will be immediately broken.
It sounds like *all* the affected packages should be fixed and rebuilt
at the same time as the new nss is pushed.
No, see above.
Yes, this keeps the old default, but all the new structures are available. All the options will work on both the patched and unpatched systems.
[I see https://src.fedoraproject.org/rpms/nss/c/614f823eb30b6ac0f0c6ea54ac9b5d26cd0f9cfe?branch=master
kept back the change for now.]
== Contingency Plan ==I don't think we should release with half of packages broken. I think
* Contingency mechanism:
If critical packages are not updated, the NSS team can turn off the
automatic move in fedora 34. If non-critical packages do not update,
then they will just fail on the first rebuild in fedora 34. Libreswan
is the only critical package we know of at this time that is affected.
Upstream already has the appropriate changes.
* Contingency deadline: beta freeze
* Blocks release? Yes, but only for critical packages.
all packages need to be updated before beta.
I don't want to hold up the change because a package that no one cares about doesn't get in. This change gives packages a full release to get fixed.
bob
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