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Bradley Kuhn (bkuhn) - 6 years ago 2015-03-12 14:59:22
bkuhn@ebb.org
VMware Lawsuit FAQ: technical description example

Written by Denver Gingerich <denver@sfconservacy.org> and me, this
description gives one example of how VMware incorporated Linux code with
vmkernel and distributed the resulting work.
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www/conservancy/static/linux-compliance/vmware-lawsuit-faq.html
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@@ -131,6 +131,276 @@
 
    (German)</a>.</p>
 
  </dd>
 

	
 
  <dt>Can you explain further in words (rather than a picture) about the central
 
  component in ESXi that the lawsuit alleges violates the GPL?</dt>
 
<dd>
 
    <p>The GPL violation at issue involves VMware's ESXi product.
 
    Conservancy independently reviewed ESXi 5.5 and its incomplete
 
      <acronym title="complete, corresponding source">CCS</acronym>
 
    release as part of our GPL enforcement efforts described above.</p>
 

	
 
    <p>Conservancy's preliminary investigation indicated that the operating
 
    system kernel of VMware ESXi product consists of three key components:
 
        <ul>
 
          <li> the proprietary component &ldquo;vmkernel&rdquo;, which is
 
            released in binary form only,</li>
 
            <li>the kernel module &ldquo;vmklinux&rdquo;, which contains modified Linux
 
Code, and for which (at least some) source code for which is provided.
 
            <li>other kernel modules with device drivers, most of which are
 
            modified Linux drivers, and for which (at least some) source code
 
              is provided.</li>
 
        </ul>
 

	
 
    <p>Conservancy examined the incomplete CCS alongside the
 
           binary &ldquo;vmkernel&rdquo; component.  Such examination indicates that function
 
           in &ldquo;vmkernel&rdquo; do make function calls to Linux's kernel code
 
           in the usual way for a single program written in C.</p>
 
</p>
 

	
 
    <dt>Doesn't VMware's &ldquo;shim layer&rdquo; insulate them from GPL
 
    obligations and allow them to keep certain code in their kernel
 
    proprietary?</dt>
 

	
 
    <p>Many in the media have talked about the possibility that VMware might
 
    use some so-called &ldquo;shim layer&rdquo; between Linux code and
 
    VMware's proprietary code.  While, for decades, there has been much talk of
 
    various mechanisms of GPL obligation avoidance, Conservancy believes that
 
    merely modifying technical details of a combination's construction
 
    does not typically influence the legal analysis in a combined or
 
    derivative work scenario.</p>
 

	
 
    <p>Furthermore, the technical details of VMware's alleged GPL violation
 
    do not even mirror the typical scenarios that have usually been called
 
    &ldquo;shim layers&rdquo;.  Conservancy's analysis of VMware's ESXi
 
    product, in fact, indicates that VMware rather flagrantly combined Linux
 
    code in their own kernel, and evidence seems to indicate the work as a
 
    whole was developed by modifying Linux code in tandem with
 
    modifications to &ldquo;vmkernel&rdquo; in a tightly coupled manner.</p>
 

	
 
    <dt>Can you give a <em>specific</em> example, with code, showing how
 
    VMware combined Linux source code with their binary-only components?</dt>
 

	
 
     <dd><p>There are numerous examples available that show this.  The
 
       details of alleged infringement specifically relating to Hellwig's
 
       contributions to Linux are of course the main matter of the
 
       allegations in the litigation, and Conservancy
 
       released <a href="#diagram">the diagram above</a> to exemplify that
 
       issue.  Conservancy continues to <a href="#court-documents">hope VMware will
 
       agree to make public all court documents</a> as a matter of public
 
       good, since the court documents discuss the specifics of alleged
 
         infringement on Hellwig's copyrights.</p>
 

	
 
       <p>However, Conservancy examined VMware's ESXi 5.5 product in detail
 
       even before Hellwig's enforcement action began.  Below is one example
 
       among many where VMware's CCS was incomplete per GPLv2&sect;2(c) and
 
       GPLv2&sect;3(a).  (One can verify these results by
 
       <a href="#verify">downloading and installing the binary and source
 
       packages for VMware's ESXi 5.5 Update 2</a>.)  Note that this
 
       example below is not necessarily regarding
 
       Hellwig's copyrights; VMware incorporated Linux code copyrighted by
 
       many others as well into their kernel.</p>
 

	
 
       <h4>Example of &ldquo;vmkernel&rdquo;'s combination with Linux code</h4>
 
       <p>As one example, examine the file
 
           called <code>vmkdrivers/src_92/vmklinux_92/vmware/linux_pci.c</code>,
 
           which can be found in the &ldquo;Open Source&rdquo; release for
 
           ESXi 5.5.0 Update 2 (5.5U2).  A small excerpt from that file, found in the
 
           function <code>LinuxPCIDeviceRemoved()</code>, reads as follows:
 
<pre>
 
if (unlikely(
 
  /* NOTE: vmk_PCIGetDeviceName is defined in vmvisor64-vmkernel */
 
  vmk_PCIGetDeviceName(vmkDev, vmkDevName, sizeof(vmkDevName)-1) != VMK_OK))
 
{
 
    vmkDevName[0] = 0;
 
}
 
[...]
 
/* VMKAPI_MODULE_CALL_VOID is a macro calling driver's remove() here */
 
VMKAPI_MODULE_CALL_VOID(pciDevExt->moduleID,
 
                        linuxDev->driver->remove,
 
                        linuxDev);
 
</pre>        
 
</p>
 
<p>The function, <code>vmk_PCIGetDeviceName()</code> must be defined, with an
 
      implementation, for this code above to work, or even compile.
 
      Inside <code>BLD/build/HEADERS/vmkapi-current-all-public/vmkernel64/release/device/vmkapi_pci_incompat.h</code>,
 
      found in the <code>vmkdrivers</code> package of ESXi 5.5U2, shows a
 
      function header definition for <code>vmk_PCIGetDeviceName()</code>.
 
      However, the source of its implementation is not provided there or
 
      anywhere in the source release.</p>
 

	
 
<p>Further evidence that the implementation of this function occurs elsewhere
 
  can by found by running <code>objdump -x</code> on the un-vmtar'ed
 
  <code>vmklinux_9</code> module.  Note the following output in the &ldquo;SYMBOL
 
  TABLE&rdquo; section:
 

	
 
<pre>
 
0000000000000000         *UND*  0000000000000000 vmk_PCIGetDeviceName
 
</pre>
 

	
 
&hellip;and the following lines found in the  &ldquo;RELOCATION RECORDS FOR
 
[.text]&rdquo; section:
 

	
 
<pre>
 
00000000000327ff R_X86_64_PC32     vmk_PCIGetDeviceName+0xfffffffffffffffc
 
0000000000035318 R_X86_64_PC32     vmk_PCIGetDeviceName+0xfffffffffffffffc
 
00000000000387e1 R_X86_64_PC32     vmk_PCIGetDeviceName+0xfffffffffffffffc
 
000000000003cf40 R_X86_64_PC32     vmk_PCIGetDeviceName+0xfffffffffffffffc
 
</pre>
 
</p>
 

	
 
<p>The above two properties both suggest that the <code>vmklinux_9</code>
 
 module requires: (a) a definition of the <code>vmk_PCIGetDeviceName()</code>
 
 function to operate, but (b) that function is not defined
 
 inside <code>vmklinux_9</code> itself.</p>
 

	
 
<p>The definition can however be found in binary-only software provided in
 
  ESXi 5.5U2 &mdash; specifically, inside a file named <code>k.b00</code>,
 
  which is located in partition 5 on a disk where ESXi has been installed (or
 
  in the ESXi 5.5U2 installer ISO image).  Running <code>file</code>
 
  after <code>gunzip</code> on this file yields &ldquo;ELF 64-bit LSB shared
 
  object&rdquo;.  Meanwhile, <code>file k.b00</code> reports &ldquo;gzip
 
  compressed data, was &lsquo;vmvisor64-vmkernel.stripped&rsquo;&rdquo;.
 
  These findings strongly suggests this is an image of the
 
  &ldquo;vmkernel&rdquo; component.  An <code>objdump -x</code> yields this
 
  &ldquo;SYMBOL TABLE&rdquo; section:
 
<pre>
 
000041800036a408 g     F .text  0000000000000137 vmk_PCIGetDeviceName
 
</pre>
 

	
 
&hellip; which indicated these binary file contains the function body
 
for  <code>vmk_PCIGetDeviceName</code>.</p>
 

	
 
<p>Finally, after detailed searching, Conservancy found no evidence that any
 
  other code (other than modified Linux code) makes calls
 
  to <code>vmk_PCIGetDeviceName</code>.  This provides a strong indication
 
  that this function's primary purpose is to combine Linux code with
 
  &ldquo;vmkernel&rdquo;.  Conservancy also found other functions where similar analysis
 
  yields similar results as above.</p>
 

	
 
<p>Given this evidence and related contextual clues, the only logical
 
  conclusions are:
 
    <ul><li><code>vmklinux_9</code>, as a binary object, dynamically links
 
 with <code>k.b00</code>, another binary object, to form a single running
 
 binary.</li>
 
      <li>That binary contains code licensed under the GPLv2, and can be
 
       distributed in binary form only under permissions provided under
 
        GPLv2 &mdash; in particular <a href="https://gnu.org/licenses/gpl-2.0.html#section2">GPLv2&sect;2</a> and <a href="https://gnu.org/licenses/gpl-2.0.html#section3">GPLv2&sect;3</a>.</li>
 
      <li>GPLv2&sect;3(a&ndash;b) requires that <q>complete corresponding
 
          machine-readable source code</q> must accompany binary
 
          distributions such as these.  GPLv2&sect;3 further states
 
          that <q>for an executable work, complete source code means all the
 
          source code for all modules it contains</q>.</li>
 
      <li>The binary work in question contains modules from <code>k.b00</code> and
 
        <code>vmlinux_9</code>.</li>
 
      <li>VMware did not provide source code for any modules found in
 
        <code>k.b00</code>.</li>
 
      <li>Therefore, VMware failed to comply with the GPLv2, as such
 
      compliance requires source code (or an offer therefor) for the material
 
        in <code>k.b00</code>.</li>
 
    </ul>
 
    </p>
 
<p>The above is but one piece of evidence among many, but hopefully it helps
 
  to explain the types of &ldquo;combined work&rdquo; violations found in
 
  VMware's ESXi product.</p>
 

	
 
<dt id="verify">How can I verify Conservancy's technical findings above?</dt>
 

	
 
<dd><p>The binary and source packages mentioned above are available
 
on VMware's website.  These packages contain the
 
previously-mentioned <code>linux_pci.c</code>,
 
<code>vmkapi_pci_incompat.h</code>, and <code>k.b00</code> files, as well as
 
    <code>vmklinux_9</code> and the source code that builds the latter.</p>
 

	
 
  <p>To obtain the source components, follow these steps (no login is required):
 

	
 
<ol>
 
<li>Visit <a href="https://my.vmware.com/web/vmware/details?downloadGroup=ESXI55U2_OSS&productId=353">https://my.vmware.com/web/vmware/details?downloadGroup=ESXI55U2_OSS&productId=353</a>.</li>
 

	
 
<li>Click the &ldquo;Download&rdquo; button beside the text that reads
 
&ldquo;Open Source Code for VMware vSphere ESXi 5.5 Update 2&rdquo;.</li>
 

	
 
<li>Confirm that the SHA-1 hash matches the published one
 
  (d121634668a137ec808b63679fd941cef9a59715), found under &ldquo;Read
 
  More&rdquo; on that web page.</li>
 

	
 
<li>Mount (or otherwise open) the
 
  downloaded <code>VMware-ESX-550U2-ODP.iso</code>.</li>
 

	
 
<li>Extract <code>vmkdrivers/src_92/vmklinux_92/vmware/linux_pci.c</code>
 
  and <code>BLD/build/HEADERS/vmkapi-current-all-public/vmkernel64/release/device/vmkapi_pci_incompat.h</code>
 
  from <code>vmkdrivers-gpl/vmkdrivers-gpl.tgz</code> with tar and gzip.</li>
 

	
 
<li>Generate <code>vmklinux_9</code> by following the steps
 
  in <code>vmkdrivers-gpl/BUILD.txt</code> in the ISO.
 
  (Note: <code>vmklinux_9</code> is also available pre-built on a running
 
  ESXi system; <a href="#vmklinux">see below for instructions on how to access it</a>).</li>
 

	
 
<li>You may need the &ldquo;Supporting Toolchain packages for VMware
 
  vSphere ESXi 5.5.0 Update 2&rdquo; file from the above download page to
 
  complete the build &mdash; upon downloading you will find it is named
 
  <code>VMware-TOOLCHAIN-550u2-ODP.iso</code> and has a SHA-1 hash of
 
  f679e81ffb2f92729917bbc64c2d541cf75b5b94.</li>
 

	
 
</ol>
 
</p>
 

	
 
  <p>To obtain the binary components, follow these steps (a login is required):
 

	
 
<ol>
 
<li>Register for an account at <a href="https://my.vmware.com/web/vmware/registration">https://my.vmware.com/web/vmware/registration</a>.</li>
 

	
 
<li>Click the &ldquo;Activate Now&rdquo; link in the follow-up email.  Enter
 
  the password used at registration time.  Click &ldquo;Continue&rdquo;.</li>
 

	
 
<li>Visit <a href="https://my.vmware.com/web/vmware/evalcenter?p=free-esxi5">https://my.vmware.com/web/vmware/evalcenter?p=free-esxi5</a>.</li>
 

	
 
<li>Click &ldquo;Register&rdquo; (under the text that reads &ldquo;You have
 
  not registered for this product&rdquo;).</li>
 

	
 
<li>Enter the number of servers you plan to install on (e.g., 1).  Click
 
  &ldquo;Continue&rdquo;.</li>
 

	
 
<li>If the &ldquo;VMware vSphere Hypervisor 5.5 Update 2 &ndash;
 
  Binaries&rdquo; section is not expanded, click the plus sign next to it.</li>
 

	
 
<li>Click the &ldquo;Manually Download&rdquo; link that's beside &ldquo;ESXi
 
  5.5 Update 2 ISO image (Includes VMware Tools)&rdquo;.</li>
 

	
 
<li>Confirm that the SHA-1 hash matches the published one (9475938b51cafc86c8b17d09f2493cb6b4fae927).</li>
 

	
 
<li>Mount (or open via some other means) the
 
downloaded <code>VMware-VMvisor-Installer-5.5.0.update02-2068190.x86_64.iso</code>.</li>
 

	
 
<li>Find the <code>k.b00</code> file in the root directory.  Extract it
 
using <code>zcat k.b00 &gt; vmvisor64-vmkernel</code> (or a similar command).
 
Repeat the steps described above using <code>objdump -x
 
vmvisor64-vmkernel</code>.</li>
 

	
 
<li id="vmklinux">To retrieve <code>vmklinux_9</code> you will need to install
 
ESXi on your system by booting the ISO and following the instructions.  Once
 
booted, you can then enable SSH access using &ldquo;Customize System/View Logs -&gt;
 
Troubleshooting Options -&gt; Enable SSH&rdquo;.  Login to the system with SSH
 
and then run <code>find /vmfs -name misc_dri.v00 -print</code>.  On the
 
resulting file, run <code>zcat misc_dri.v00 &gt; misc_dri.vmtar</code> then
 
<code>vmtar -x misc_dri.vmtar -o misc_dri.tar</code>.  You can then extract
 
<code>misc_dri.tar</code> using the usual <code>tar</code> to extract
 
<code>usr/lib/vmware/vmkmod/vmklinux_9</code>.  The <code>misc_dri.v00</code>
 
file is also available next to <code>k.b00</code> in the root directory of
 
the ISO (mentioned above), but the <code>vmtar</code> command itself is only
 
available when logged into an ESXi system. <code>vmtar</code> can be found
 
at <code>bin/vmtar</code> inside
 
<code>sb.v00</code> on the ISO, but one needs <code>vmtar</code> to open
 
<code>sb.v00</code>, similar to <code>misc_dri.v00</code> above.</li>
 

	
 
</ol>
 
</p>
 

	
 
  <p>Note that VMware may present you with <acronym title="End User Licensing Agreement">EULA</acronym>s and <acronym title="Terms of Service">ToS</acronym> when you download
 
  software from VMware's website.  Conservancy strongly suggests that you review these
 
  terms in great detail with the assistance of your own legal counsel before
 
  downloading the software and/or engaging in the process that Conservancy
 
  discusses above.</p>
 

	
 
  <dt>Have others issued statements of support about this action?</dt>
 
  <dd>Various individuals and groups have publicly stated their support for
 
    Conservancy's and Hellwig's actions in this matter.  They include:
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