tree 9fc03934b8f93c2ebc702bcaa575e676d29065f0
parent c08d7ba0f32bfca9f1705766449ce5f83b5a1b41
author David Benjamin <davidben@google.com> 1756490123 -0400
committer Boringssl LUCI CQ <boringssl-scoped@luci-project-accounts.iam.gserviceaccount.com> 1756959714 -0700

Make ASN1_EXTERN_FUNCS's parse callback CBS-based

Having to keep flipping back and forth between the calling conventions
when bridging rewritten types is tedious.

This does not rewrite the core of tasn_dec.cc (although at this point
much of it is already CBS-based), but it does suggest a calling
convention for it. Right now, the internal calling convention is the
double-pointer thing from d2i, with an extra twist that functions must
return 0 for error, 1 for success, and -1 for "success but parsed
nothing".

This proposes a CBS in/out param to return how bytes we consumed, and a
plain success/error return value. The -1 case can be modeled as
successfully consuming zero bytes.

For now, we still have to bridge the two inside tasn_dec.cc. Also for
this CL I have not yet rewritten the messy X509_NAME parser, or the
tasn_dec.cc parser.

There's also a messy situation where this object sometimes is called
with an existing object already there, and sometimes without one. I
don't see a good way to avoid that one, but hopefully it'll become less
and as important as we stop using the tasn system.

Bug: 42290418
Change-Id: I3969e19ade81aedf449b4baf139fe5f5b1dd867b
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/81776
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>