Do not condition CRYPTO_is_RDRAND_capable on __RDRND__

On some AMD processors, we will act as if the hardware is
RDRAND-incapable, even it actually supports it, to workaround some bugs
where their RDRAND would return all ones. However, this works by
clearing the RDRAND bit, and the static capability check bypasses this.

That means, when compiling binaries for an RDRAND-capable baseline CPU,
we might end up disabling the workaround. Thanks to Brian Smith for
noticing this.

Fortunately, we believe this had no real impact and the workaround was
actually redundant with other parts of our PRNG logic. See
https://crbug.com/boringssl/675#c2 for a more detailed analysis.

Fixed: 675
Change-Id: I91d844cfaafb22eb29254f81fb6719588937a4a8
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/65267
Commit-Queue: David Benjamin <davidben@google.com>
Auto-Submit: David Benjamin <davidben@google.com>
Reviewed-by: Bob Beck <bbe@google.com>
1 file changed
tree: 3b296986c80eb539d74b9a934aaf49afbcdb872b
  1. .github/
  2. cmake/
  3. crypto/
  4. decrepit/
  5. fuzz/
  6. include/
  7. pki/
  8. rust/
  9. ssl/
  10. third_party/
  11. tool/
  12. util/
  13. .clang-format
  14. .gitignore
  15. API-CONVENTIONS.md
  16. BREAKING-CHANGES.md
  17. BUILDING.md
  18. CMakeLists.txt
  19. codereview.settings
  20. CONTRIBUTING.md
  21. FUZZING.md
  22. go.mod
  23. go.sum
  24. INCORPORATING.md
  25. LICENSE
  26. PORTING.md
  27. README.md
  28. SANDBOXING.md
  29. sources.cmake
  30. 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.

Project links:

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