Make ASN1_STRING_TABLE_add thread-safe and document.

This function is a little awkward. It mutates global data, so if two
libraries in the address space both attempt to define a custom OID, they
will conflict. But some existing code uses it so, as long as it does so,
we should make it thread-safe.

Along the way, I've switched it to a hash table and removed the ability
to overwrite existing entries. Previously, overwriting a built-in table
would crash (on platforms where const structures are write-protected).
Overwriting a dynamic table implemented this weird merging algorithm.
The one caller I've seen does not appear to need this feature.

I've also switched ASN1_STRING_TABLE_cleanup to a no-op, matching our
other global cleanup functions. This function is not safe to call
without global knowledge of all other uses of the library.

Update-Note: ASN1_STRING_TABLE_add no longer allows overwrite existing
entries. In most cases, this would crash or trigger a race condition

Bug: 426
Change-Id: Ie024cca87feaef3ff10064b452f3a860844544da
Reviewed-by: Adam Langley <>
4 files changed
tree: 14d9aaef0b5cc8bb15ccb3c6c6cd85084c38ae8a
  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:

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