Fix client handling of 0-RTT rejects with cipher mismatch.

Servers can only accept 0-RTT if the ciphers match. If they reject
0-RTT, however, they may change the cipher suite and even the PRF hash.
This is tricky, however, because the 0-RTT accept or reject signal comes
in EncryptedExtensions, which is *after* the new cipher suite is
installed. (Although a client could infer 0-RTT is rejected based on the
cipher suite if it wanted.)

While we correctly handled the PRF hash switch, we get the cipher suite
mixed up due to dependency on SSL_get_session and incorrectly decrypt
EncryptedExtensions. Fix this and add some tests.

Change-Id: Ia20f2ed665cf601d30a38f0c8d4786c4c111019f
Reviewed-by: Steven Valdez <>
Commit-Queue: David Benjamin <>
11 files changed
tree: b87ae57e395662dd0fe1004f6e55e52064e00ae1
  1. .clang-format
  2. .github/
  3. .gitignore
  7. CMakeLists.txt
  15. codereview.settings
  16. crypto/
  17. decrepit/
  18. fuzz/
  19. go.mod
  20. include/
  21. sources.cmake
  22. ssl/
  23. third_party/
  24. tool/
  25. util/


BoringSSL is a fork of OpenSSL that is designed to meet Google's needs.

Although BoringSSL is an open source project, it is not intended for general use, as OpenSSL is. We don't recommend that third parties depend upon it. Doing so is likely to be frustrating because there are no guarantees of API or ABI stability.

Programs ship their own copies of BoringSSL when they use it and we update everything as needed when deciding to make API changes. This allows us to mostly avoid compromises in the name of compatibility. It works for us, but it may not work for you.

BoringSSL arose because Google used OpenSSL for many years in various ways and, over time, built up a large number of patches that were maintained while tracking upstream OpenSSL. As Google's product portfolio became more complex, more copies of OpenSSL sprung up and the effort involved in maintaining all these patches in multiple places was growing steadily.

Currently BoringSSL is the SSL library in Chrome/Chromium, Android (but it's not part of the NDK) and a number of other apps/programs.

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