Add a helper function for parsing extensions blocks.

TLS 1.3 adds a number of places with extensions blocks that don't easily
fit into our ClientHello/EncryptedExtensions callbacks. Between
HelloRetryRequest, ServerHello, draft 18 going nuts with Certificate,
and NewSessionTicket when we do 0-RTT, this passes the "abstract things
that are repeated three times" sniff test.

For now, it rejects unknown extensions, but it will probably grow an
allow_unknown parameter for NewSessionTicket.

This involves disabling some MSVC warnings, but they're invalid as of
C99 which we otherwise require. See
https://connect.microsoft.com/VisualStudio/feedback/details/1230248/remove-c99-related-warnings-or-make-them-off-by-default

Change-Id: Iea8bf8ab216270c081dd63e79aaad9ec73b3b550
Reviewed-on: https://boringssl-review.googlesource.com/12233
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
5 files changed
tree: bc0b32040f90b0c97daee5e1983c18d3a0bf758d
  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: