Fix strict aliasing violations in crypto/asn1 from ASN1_VALUE*

The table-based parser constantly needs to load pointers without knowing
their type. At one point I'd thought we could embed load/store thunks
into the table, but this is unnecessary. We can just load/store through
memcpy. This is horrific, but should work.

This sidesteps the issue documented in `ASN1_item_d2i`, because we don't
actually have to pick one or the other.

NB: Although these violations are fixed, BoringSSL still recommends
consumers build with strict aliasing disabled. There are likely more
violations we are unaware of. Before revisiting this decision, we would
need Clang's TypeSanitizer, some equivalent, to become robust enough to
run in CI and complete enough to cover all strict aliasing assumptions
our compilers might make.

Bug: 42290308
Change-Id: Icb7812cee921202c4175f841ea49e8254b0ba95a
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/97160
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
12 files changed
tree: 444ab9f590d63a9602e87af0481daf376fc8cfcb
  1. .bcr/
  2. .github/
  3. bench/
  4. cmake/
  5. crypto/
  6. decrepit/
  7. docs/
  8. fuzz/
  9. gen/
  10. include/
  11. infra/
  12. pki/
  13. rust/
  14. ssl/
  15. third_party/
  16. tool/
  17. util/
  18. .bazelignore
  19. .bazelrc
  20. .bazelversion
  21. .clang-format
  22. .clang-format-ignore
  23. .clangd
  24. .gitattributes
  25. .gitignore
  26. API-CONVENTIONS.md
  27. AUTHORS
  28. BREAKING-CHANGES.md
  29. BUILD.bazel
  30. build.json
  31. BUILDING.md
  32. CMakeLists.txt
  33. codereview.settings
  34. CONTRIBUTING.md
  35. FUZZING.md
  36. go.mod
  37. go.sum
  38. INCORPORATING.md
  39. LICENSE
  40. MODULE.bazel
  41. MODULE.bazel.lock
  42. PORTING.md
  43. PRESUBMIT.py
  44. PrivacyInfo.xcprivacy
  45. README.md
  46. SANDBOXING.md
  47. SECURITY.md
  48. 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:

To file a security issue, use the Chromium process and mention in the report this is for BoringSSL. You can ignore the parts of the process that are specific to Chromium/Chrome.

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