Estonian IDs issued between September 2014 to September 2015 are broken and use
negative moduli. They last five years and are common enough that we need to
work around this bug.
Add parallel "buggy" versions of BN_cbs2unsigned and RSA_parse_public_key which
tolerate this mistake, to align with OpenSSL's previous behavior. This code is
currently hooked up to rsa_pub_decode in RSA_ASN1_METHOD so that d2i_X509 is
tolerant. (This isn't a huge deal as the rest of that stack still uses the
legacy ASN.1 code which is overly lenient in many other ways.)
In future, when Chromium isn't using crypto/x509 and has more unified
certificate handling code, we can put client certificates under a slightly
different codepath, so this needn't hold for all certificates forever. Then in
September 2019, when the broken Estonian certificates all expire, we can purge
this codepath altogether.
BUG=532048
Change-Id: Iadb245048c71dba2eec45dd066c4a6e077140751
Reviewed-on: https://boringssl-review.googlesource.com/5894
Reviewed-by: Adam Langley <agl@google.com>
231cb82145