This is consistent with the old behavior of d2i_*_fp and avoids tripping
Conscrypt's unnecessarily fragile error-handling (see
https://github.com/google/conscrypt/pull/552).
Additionally, by source inspection, CPython expects
ASN1_R_HEADER_TOO_LONG on EOF, analogously to PEM_R_NO_START_LINE. Fix
that. The other errors are a bit haphazard in the old implementation
(that code is really hard to follow), so I didn't match it too
carefully. In particular, OpenSSL would report ASN1_R_HEADER_TOO_LONG on
some generic tag parsing, but that is inconsistent with
ASN1_R_HEADER_TOO_LONG being an EOF signal.
Update-Note: https://boringssl-review.googlesource.com/32106 may have
caused some compatibility issues. This should fix it.
Change-Id: Idfe2746ffd7733de4338e14c58a40753e98a791e
Reviewed-on: https://boringssl-review.googlesource.com/c/32444
Reviewed-by: Steven Valdez <svaldez@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>