Support Android's "baremetal" target

This corresponds to the libcrypto_baremetal build target in Android,
which is an embedded-style platform that uses a subset of the bionic
libc. It will also, eventually, use getentropy for its PRNG.

As part of this, generalize the OPENSSL_TRUSTY exclusion for file BIOs
to OPENSSL_NO_FILESYSTEM. Upstream OpenSSL uses OPENSSL_NO_STDIO, but
that excludes all of FILE entirely. We already require FILE in quite a
few places (urandom.c, self_test.c) for writing to stderr, and FILE is
part of C standard library. So, let's tentatively say that we require
you have FILE and stderr.

Instead, OPENSSL_NO_FILESYSTEM is saying you don't have fopen. You're
still required to have the three std{in,out,err} FILEs, and given a
FILE, you need to allow the standard operations on it. (Possibly in
forms that always fail.)

To keep us honest, whenever a function is excluded, I've dropped it from
the header too, and followed callers up the chain. I have not attempted
to make the tests work when these are excluded. Later CLs in this series
will do the same for NO_SOCK and NO_POSIX_IO. This was a little tedious,
but not too bad.

(I assume we'll end up changing our minds on this a lot. For now, let's
try this.)

I haven't yet restored OPENSSL_RAND_TRUSTY or removed the OPENSSL_TRUSTY
ifdef on file.c. Having a separate CL makes it a bit easier to revert if
something goes wrong.

This depends on
https://android-review.googlesource.com/c/platform/bionic/+/2659335,
which fixes the header bionic uses for getentropy.

Bug: 629, b:291102972
Change-Id: Idd839cd3fa4253128de54bd1be7da261dbcdeb7c
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/61726
Auto-Submit: David Benjamin <davidben@google.com>
Reviewed-by: Bob Beck <bbe@google.com>
Commit-Queue: Bob Beck <bbe@google.com>
13 files changed
tree: f8591cde74a9e6c302fa400b5bc734814d2b2736
  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: