Fix some enum issues in the test-only BORINGSSL_FIPS_COUNTERS build

This fixes b/342634459.

enums are weird. They're neither tight sum types, nor ints with
designated values but something in between.

By default (i.e. if you do not say `enum Foo : int`, which isn't in C
until very new versions), an enum's range of valid values is the
smallest hypothetical-bit-width signed or unsigned integer that can fit
all the values. So, the following enum can only hold 0, 1, 2, or 3, and
all values outside that range are UB.

  enum E {
    A = 0,
    B = 2,
  }

Meanwhile, enum is signed and can hold values -2, -1, 0, 1:

  enum E {
    A = -1,
    B = 1,
  }

This is incredibly bizarre. This has two consequences. First, clang
emits a warning like the following:

.../boringssl/crypto/fipsmodule/self_check/fips.c:75:15: error: result of comparison of unsigned enum expression < 0 is always false [-Werror,-Wtautological-unsigned-enum-zero
-compare]
   75 |   if (counter < 0 || counter > fips_counter_max) {
      |       ~~~~~~~ ^ ~

Second, this loop over enum values in the unit test trips UBSan.

[----------] 1 test from CryptoTest
[ RUN      ] CryptoTest.FIPSCountersEVP_AEAD
.../boringssl/crypto/crypto_test.cc:51:8: runtime error: load of value 4, which is not a valid value for type 'fips_counter_t'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /usr/local/google/home/davidben/boringssl/crypto/crypto_test.cc:51:8

To avoid this, just do our arithemetic in integer space and only move to
enums at the edges.

Change-Id: Icbd0e41604ce2aa67be8d394b03c7de50062199c
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/68768
Commit-Queue: David Benjamin <davidben@google.com>
Auto-Submit: David Benjamin <davidben@google.com>
Reviewed-by: Bob Beck <bbe@google.com>
Reviewed-by: Adam Langley <agl@google.com>
2 files changed
tree: d299c683299da0063c5d73af2c6b2a20c4c6cdd4
  1. .github/
  2. cmake/
  3. crypto/
  4. decrepit/
  5. fuzz/
  6. gen/
  7. include/
  8. pki/
  9. rust/
  10. ssl/
  11. third_party/
  12. tool/
  13. util/
  14. .bazelignore
  15. .bazelrc
  16. .clang-format
  17. .gitignore
  18. API-CONVENTIONS.md
  19. BREAKING-CHANGES.md
  20. BUILD.bazel
  21. build.json
  22. BUILDING.md
  23. CMakeLists.txt
  24. codereview.settings
  25. CONTRIBUTING.md
  26. FUZZING.md
  27. go.mod
  28. go.sum
  29. INCORPORATING.md
  30. LICENSE
  31. MODULE.bazel
  32. MODULE.bazel.lock
  33. PORTING.md
  34. PrivacyInfo.xcprivacy
  35. README.md
  36. SANDBOXING.md
  37. 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: