Use a separate timeout scheme for TLS 1.3.

In TLS 1.2, resumption's benefits are more-or-less subsumed by False
Start. TLS 1.2 resumption lifetime is bounded by how much traffic we are
willing to encrypt without fresh key material, so the lifetime is short.
Renewal uses the same key, so we do not allow it to increase lifetimes.

In TLS 1.3, resumption unlocks 0-RTT. We do not implement psk_ke, so
resumption incorporates fresh key material into both encrypted traffic
(except for early data) and renewed tickets. Thus we are both more
willing to and more interested in longer lifetimes for tickets. Renewal
is also not useless. Thus in TLS 1.3, lifetime is bound separately by
the lifetime of a given secret as a psk_dhe_ke authenticator and the
lifetime of the online signature which authenticated the initial
handshake.

This change maintains two lifetimes on an SSL_SESSION: timeout which is
the renewable lifetime of this ticket, and auth_timeout which is the
non-renewable cliff. It also separates the TLS 1.2 and TLS 1.3 timeouts.
The old session timeout defaults and configuration apply to TLS 1.3, and
we define new ones for TLS 1.3.

Finally, this makes us honor the NewSessionTicket timeout in TLS 1.3.
It's no longer a "hint" in 1.3 and there's probably value in avoiding
known-useless 0-RTT offers.

BUG=120

Change-Id: Iac46d56e5a6a377d8b88b8fa31f492d534cb1b85
Reviewed-on: https://boringssl-review.googlesource.com/13503
Reviewed-by: Adam Langley <agl@google.com>
14 files changed
tree: 7e11401bbd5e8ae869badb7c32496bd92b09a8a6
  1. .github/
  2. crypto/
  3. decrepit/
  4. fuzz/
  5. include/
  6. infra/
  7. ssl/
  8. third_party/
  9. tool/
  10. util/
  11. .clang-format
  12. .gitignore
  13. API-CONVENTIONS.md
  14. BUILDING.md
  15. CMakeLists.txt
  16. codereview.settings
  17. CONTRIBUTING.md
  18. FUZZING.md
  19. INCORPORATING.md
  20. LICENSE
  21. PORTING.md
  22. README.md
  23. STYLE.md
README.md

BoringSSL

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.

There are other files in this directory which might be helpful: