[openssl-dev] [openssl.org #4063] Client Hello longer than 2^14 bytes are rejected

[Hubert Kario via RT]

Current OpenSSL-1.0.1, 1.0.2 as well as state-machine-rewrite branches 
reject Client Hello messages bigger than 2^14+4 bytes.

RFC 5246 specifies maximum size of just the extensions field to be 
2^16-1:

      struct {
          ProtocolVersion client_version;
          Random random;
          SessionID session_id;
          CipherSuite cipher_suites<2..2^16-2>;
          CompressionMethod compression_methods<1..2^8-1>;
          select (extensions_present) {
              case false:
                  struct {};
              case true:
                  Extension extensions<0..2^16-1>;
          };
      } ClientHello;

reproducer:
openssl req -x509 -newkey rsa -keyout localhost.key -out localhost.crt\
-nodes -batch
~/dev/openssl/apps/openssl s_server -key localhost.key -cert\
localhost.crt -www

pip install --pre tlslite-ng
git clone https://github.com/tomato42/tlsfuzzer.git

cd tlsfuzzer
PYTHONPATH=. python scripts/test-record-layer-fragmentation.py
-- 
Regards,
Hubert Kario
Quality Engineer, QE BaseOS Security team
Web: www.cz.redhat.com
Red Hat Czech s.r.o., Purkyňova 99/71, 612 45, Brno, Czech Republic
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