Fix crash when flushing an SSL BIO.

OpenSSL synchronizes bio->next_bio and ssl->rbio with a variety of
callbacks, so BIO_copy_next_retry worked. We do not, so attempting to
flush the BIO crashed.

The SSL BIO is a compatibility hack and intentionally much more limited,
so start by just copying things from the right BIO directly. Add a basic
unit test for SSL BIOs. If we need to, we can implement a more complex
synchronization later.

Additionally reject reconfiguring an SSL BIO because that will leak the
object right now.

Change-Id: I724c95ab6f1a3a1aa1889b0483c81ce3bdc534ae
Reviewed-by: Adam Langley <>
4 files changed
tree: 9a16097e7a152a3b900cf7599ce7a0bd0e4c26c8
  1. .github/
  2. crypto/
  3. decrepit/
  4. fuzz/
  5. include/
  6. ssl/
  7. third_party/
  8. tool/
  9. util/
  10. .clang-format
  11. .gitignore
  15. CMakeLists.txt
  16. codereview.settings
  19. go.mod
  20. go.sum
  26. sources.cmake


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.

Project links:

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