The only place it is used is EC_KEY_{dup,copy} and no one calls that
function on an EC_KEY with ex_data. This aligns with functions like
RSAPublicKey_dup which do not copy ex_data. The logic is also somewhat
subtle in the face of malloc errors (upstream's PR 3323).
In fact, we'd even changed the function pointer signature from upstream,
so BoringSSL-only code is needed to pass this pointer in anyway. (I
haven't switched it to CRYPTO_EX_unused because there are some callers
which pass in an implementation anyway.)
Note, in upstream, the dup hook is also used for SSL_SESSIONs when those
are duplicated (for TLS 1.2 ticket renewal or TLS 1.3 resumption). Our
interpretation is that callers should treat those SSL_SESSIONs
equivalently to newly-established ones. This avoids every consumer
providing a dup hook and simplifies the interface.
(I've gone ahead and removed the TODO(fork). I don't think we'll be able
to change this API. Maybe introduce a new one, but it may not be worth
it? Then again, this API is atrocious... I've never seen anyone use argl
and argp even.)
BUG=21
Change-Id: I6c9e9d5a02347cb229d4c084c1e85125bd741d2b
Reviewed-on: https://boringssl-review.googlesource.com/16344
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
