Description of problem:
If the client hello message includes more than 32 extensions, GnuTLS will completely ignore presence of those extensions.

Version-Release number of selected component (if applicable):
gnutls-3.4.15-1.fc24.x86_64

How reproducible:
Always

Steps to Reproduce:
  openssl req -x509 -newkey rsa:2048 -keyout localhost.key -out localhost.crt -subj /CN=localhost -nodes -batch
  gnutls-serv --http -p 4433 --x509keyfile localhost.key --x509certfile localhost.crt --disable-client-cert

In another console:
  git clone https://github.com/tomato42/tlsfuzzer.git
  pushd tlsfuzzer
  git clone https://github.com/tomato42/tlslite-ng.git .tlslite-ng
  ln -s .tlslite-ng/tlslite tlslite
  git clone https://github.com/warner/python-ecdsa.git .python-ecdsa
  ln -s .python-ecdsa/ecdsa ecdsa
  PYTHONPATH=. python scripts/test-large-number-of-extensions.py


Actual results:
...
63 extensions ...
Error encountered while processing node <tlsfuzzer.expect.ExpectServerHello object at 0x7f451d1c0150> (child: <tlsfuzzer.expect.ExpectCertificate object at 0x7f451d1c0190>) with last message being: <tlslite.messages.Message object at 0x7f451be366d0>
Error while processing
Traceback (most recent call last):
  File "scripts/test-large-number-of-extensions.py", line 168, in main
    runner.run()
  File "/tmp/tlsfuzzer/tlsfuzzer/runner.py", line 168, in run
    node.process(self.state, msg)
  File "/tmp/tlsfuzzer/tlsfuzzer/expect.py", line 174, in process
    assert ext is not None
AssertionError
...

Expected results:

Test end
successful: 21
failed: 0


Additional info:

Fixed upstream: https://gitlab.com/gnutls/gnutls/issues/136