Work around more C language bugs with empty spans.

C's specification text around pointer arithmetic is buggy and fails to
account for empty spans. Empty spans are typically represented as
ptr=NULL and len=0, so (T*)NULL + 0 must be defined for ptr + len to
reliably work. C++ does not have this bug and specifies this correctly.

This language bug has made its way over to newer versions of UBSan,
which enforce this. In the short term, add bogus length checks as a
workaround. However, unlike the memcpy language bug, we cannot address
this systematically. In the long term, we need to switch libcrypto to
building as C++ for a real fix.

To test this, update our clang revision to that in Note
that clang revision was later reverted in Chromium for seemingly
unrelated reasons.

This newer UBSan also catches a memcpy/OPENSSL_memcpy issue in
siphash.c, from the earlier C NULL bug we'd been working around.

Bug: chromium:1019588, chromium:1019644
Change-Id: I460e547c8cd740db68da8cc2a3a970276ec92e90
Reviewed-by: Adam Langley <>
Commit-Queue: Adam Langley <>
5 files changed
tree: c93b8be114138bd489070f2dcbdfb19268971db1
  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.

Project links:

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