Re: openssl as a system library

2013-06-10 Thread Kees Cook
 a Major Component, but which is not part of that Major
   Component, and (b) serves only to enable use of the work with that
   Major Component, or to implement a Standard Interface for which an
   implementation is available to the public in source code form.  A
   Major Component, in this context, means a major essential component
   (kernel, window system, and so on) of the specific operating system
   (if any) on which the executable work runs, or a compiler used to
   produce the work, or an object code interpreter used to run it.
   
 The Corresponding Source for a work in object code form means all
   the source code needed to generate, install, and (for an executable
   work) run the object code and to modify the work, including scripts to
   control those activities.  However, it does not include the work's
   System Libraries, or general-purpose tools or generally available free
   programs which are used unmodified in performing those activities but
   which are not part of the work.  For example, Corresponding Source
   includes interface definition files associated with source files for
   the work, and the source code for shared libraries and dynamically
   linked subprograms that the work is specifically designed to require,
   such as by intimate data communication or control flow between those
   subprograms and other parts of the work.
 
 Now, first, we must consider whether it is possible to regard OpenSSL as
 a System Library here.  I am not entirely sure I understand the
 qualification in (a), but I think that it's trying to talk about glue
 libraries that you need to make use of system facilities: for example,
 in this model libc is merely a library that enables use of the work with
 the system's kernel.  But, in any case, if we only consider (b) (which
 we can do since it's and), OpenSSL does not merely serve to enable use
 of a work with anything (it provides significant facilities itself), and
 it does not implement a Standard Interface in any reading I can make of
 that term (this is usually interpreted to mean if the GPL-incompatible
 library is just one choice of many that plug into the same generic slot,
 then it doesn't matter - but the problem at hand here only arises
 because it hasn't been made to work with GnuTLS!).

I think another reading of implement a Standard Interface could describe
the crypto communication side. The protocols OpenSSL implements are very
public, so that seems to count. And even if not, since OpenSSL tends
to be the cross-platform defacto standard for crypto communications,
I would think in the case of interfaces specified for a particular
programming language, one that is widely used among developers working
in that language. counts too. (See examples for OpenSSL in Secure
Programming Cookbook for C and C++, or how it is the recommended way to
implement SSL in Wheeler's Secure Programs HOWTO:
http://www.dwheeler.com/secure-programs/Secure-Programs-HOWTO.html#CRYPTO )

Additionally there is the note is available to the public in source
code form for which OpenSSL certainly is again, which seems to follow
my earlier assumption about wanting to make sure all source is available
to the end user.

 Secondly, we need to consider whether OpenSSL meets the requirements of
 general-purpose tools or generally available free programs which are
 used unmodified in performing those activities but which are not part of
 the work.  The example that follows appears to suggest that this is for
 things you use using narrow arm's-length interfaces, for example forking
 sed and reading its output, and it specifically calls out shared
 libraries ... that the work is specifically designed to require as
 cases that still fall under Corresponding Source.  Again, if MongoDB
 were not specifically designed to require OpenSSL - if it were possible
 to plug in something like GnuTLS - then we wouldn't be having this
 discussion in the first place.

Well, since I still consider it a system library, this isn't something
that needs to be considered. But if I did, I think this isn't really a
concern since the source for OpenSSL IS available.

 So I'm afraid that, while the reasoning does seem to differ for the
 GPLv3, I think the general position still stands.  In fact, since it
 isn't grounded in a dispute about whether two packages we ship
 accompany each other, the argument seems if anything stronger for the
 (A)GPLv3.

And ironically, I find the GPLv3 has even more support for my position. :)

  One of the common bug and feature requests we get is squid to support
  SSL[0][1].  We know that a significant volume of openssl users, take
  the source package and make minimal modifications to rebuild it
  locally, with openssl support.  Judging from the bug reports, this
  also seems to affect ubuntu.com’s services that use SSL (ie, the
  Ubuntu packages are not even fit for Ubuntu infrastructure).
 
 In this specific case, at least one squid upstream developer has
 explicitly

openssl as a system library

2013-05-01 Thread Dave Walker
Hi,

I would like openssl to be considered a system library in Ubuntu.  As
a developer, it seems very clear to me that it is essentially treated
as such with it's penetration in packages probably as common as other
shared libraries.

I would suggest that an openssl derived libssl.so being included in
the default Launchpad buildd chroots substantiates this, along with
other core libraries.  In addition, I do not believe any Ubuntu media
avoids installing openssl by default.

One of the common bug and feature requests we get is squid to support
SSL[0][1].  We know that a significant volume of openssl users, take
the source package and make minimal modifications to rebuild it
locally, with openssl support.  Judging from the bug reports, this
also seems to affect ubuntu.com’s services that use SSL (ie, the
Ubuntu packages are not even fit for Ubuntu infrastructure).

I believe this to be both a usability and potentially more
importantly, a security issue as a large volume of users are being
compelled to use custom packages that does not benefit from the Main
archive security support it normally would.

An upstream exception has been sought, but due to lack of centralised
copyright handling - it has not been viable to get all the copyright
holders in agreement.

Additionally, work to support gnutls could also be invested - This is
making some progress, but has been slow.  As Ubuntu’s primary
intention is to be a distribution, we have not been able to justify
resources to work on this.

We are now seeing a similar issue with mongodb, and would ask for
clarification that openssl is considered a “system library”, and
therefore allow openssl support by-default, in packages that can make
use of it.  This would seem to be in the best interest of users.

This being said, as good Free Software advocates - I would like to
stipulate that every effort should be made to draw upstream copyright
holders to granting an OpenSSL exception, and this is a pragmatic
direction, whilst being faithful to Ubuntu’s free software
commitments.

I would like to draw contrast with other Linux distributions that
consider such matters.  One is distribution Fedora, where they seem to
specifically outline that they consider openssl to be a system
library[2].

[0] https://bugs.launchpad.net/ubuntu/+source/squid/+bug/16669
[1] https://bugs.launchpad.net/ubuntu/+source/squid3/+bug/1088971
[2] 
https://fedoraproject.org/wiki/Licensing:FAQ?rd=Licensing/FAQ#What.27s_the_deal_with_the_OpenSSL_license.3F

Thanks.

-- 
Kind Regards,

Dave Walker dave.wal...@canonical.com
Engineering Manager,
Ubuntu Server

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Re: openssl as a system library

2013-05-01 Thread Colin Watson
On Wed, May 01, 2013 at 11:25:17AM +0100, Dave Walker wrote:
 I would like openssl to be considered a system library in Ubuntu.  As
 a developer, it seems very clear to me that it is essentially treated
 as such with it's penetration in packages probably as common as other
 shared libraries.

The key phrase in the GPL (at least v2) is unless that component itself
accompanies the executable.  Debian and Fedora (to take two examples)
have historically disagreed about the interpretation of this phrase.
The Debian position is explained in
http://lists.debian.org/debian-legal/2002/10/msg00113.html, and in this
case boils down to if we're shipping both mongodb and openssl, Debian
is a single OS and that constitutes the component accompanying the
executable.

I'm afraid I agree with Debian's position on this and disagree with
Fedora's, and would similarly require for Ubuntu that any GPLed package
linking against OpenSSL contain an explicit exception sufficiently
general to apply to both us and to people who make derivative works
based on our package or who mirror our package.  If the upstream thinks
that it does not infringe upon their particular requirements to use
OpenSSL then in general we ought to be able to extract such an exception
from them, while if they do think that it's an infringement then we
shouldn't be shipping it that way anyway.

A further reason beyond Steve's explanation in the linked mail why I am
wary of ever attempting to use the system library exception for
libraries shipped as part of Ubuntu is that I think it's a subversion of
the original intent of that clause of the GPL.  My understanding is that
the original reason that clause is there was to permit distributing
GPLed executables for non-free operating systems where for instance the
C library was not available under a GPL-compatible licence; the
bootstrapping problem there is obvious and it makes sense for the GPL to
have provision for that case.  The GPL FAQ gives a modern example of
distributing a binary linked against the Windows Visual C++ runtime
library, and says (for GPLv2, I think) To prevent unscrupulous
distributors from trying to use the System Library exception as a
loophole, the GPL says that libraries can only qualify as System
Libraries as long as they're not distributed with the program itself.

Now, MongoDB appears to be AGPLv3, and the GPLv3 is a bit more specific
here.  It's thus worth a little reanalysis based on the text of the
GPLv3.  Here it is:

A Standard Interface means an interface that either is an official
  standard defined by a recognized standards body, or, in the case of
  interfaces specified for a particular programming language, one that
  is widely used among developers working in that language.
  
The System Libraries of an executable work include anything, other
  than the work as a whole, that (a) is included in the normal form of
  packaging a Major Component, but which is not part of that Major
  Component, and (b) serves only to enable use of the work with that
  Major Component, or to implement a Standard Interface for which an
  implementation is available to the public in source code form.  A
  Major Component, in this context, means a major essential component
  (kernel, window system, and so on) of the specific operating system
  (if any) on which the executable work runs, or a compiler used to
  produce the work, or an object code interpreter used to run it.
  
The Corresponding Source for a work in object code form means all
  the source code needed to generate, install, and (for an executable
  work) run the object code and to modify the work, including scripts to
  control those activities.  However, it does not include the work's
  System Libraries, or general-purpose tools or generally available free
  programs which are used unmodified in performing those activities but
  which are not part of the work.  For example, Corresponding Source
  includes interface definition files associated with source files for
  the work, and the source code for shared libraries and dynamically
  linked subprograms that the work is specifically designed to require,
  such as by intimate data communication or control flow between those
  subprograms and other parts of the work.

Now, first, we must consider whether it is possible to regard OpenSSL as
a System Library here.  I am not entirely sure I understand the
qualification in (a), but I think that it's trying to talk about glue
libraries that you need to make use of system facilities: for example,
in this model libc is merely a library that enables use of the work with
the system's kernel.  But, in any case, if we only consider (b) (which
we can do since it's and), OpenSSL does not merely serve to enable use
of a work with anything (it provides significant facilities itself), and
it does not implement a Standard Interface in any reading I can make of
that term (this is usually interpreted to mean if the GPL-incompatible
library is just