ASN1_get_object should not accept large universal tags.

The high bits of the type get used for the V_ASN1_NEG bit, so when used with
ASN1_ANY/ASN1_TYPE, universal tags become ambiguous. This allows one to create
a negative zero, which should be impossible. Impose an upper bound on universal
tags accepted by crypto/asn1 and add a test.


(Cherry-picked from fb2c6f8c8565e1e2d85c24408050c96521acbcdc.)

Change-Id: Ia988acf73fd11807869510a2b3825637a8d98853
Reviewed-by: Adam Langley <>
6 files changed
tree: bc6ef52b4e82da01780808e0dfcd2a3d09bf91eb
  1. crypto/
  2. decrepit/
  3. fuzz/
  4. include/
  5. ssl/
  6. tool/
  7. util/
  8. .clang-format
  9. .gitignore
  11. CMakeLists.txt
  12. codereview.settings


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.

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

  • how to port OpenSSL-using code to BoringSSL.
  • how to build BoringSSL
  • rules and guidelines for coding style.
  • include/openssl: public headers with API documentation in comments. Also available online.
  • information about fuzzing BoringSSL.