tree fbeb215d01c93f5dbf471689fccf2371f44bfb34
parent f7b87c83fa5a8f3f30058033ea41d4f24836d44a
author David Benjamin <davidben@google.com> 1615747581 -0400
committer CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> 1615848792 +0000

Document ASN1_TYPE and related functions.

The representation here is a bit more messy than necessary. In doing so,
clean up the variable names and smooth away two rough edges:

- X509_ALGOR_get0 would leave *out_param_value uninitialized if
  *out_param_type is V_ASN1_UNDEF. Instead, set it to NULL, so callers
  do not accidentally use an uninitialized pointer.

- X509_PUBKEY_set0_param, if key is NULL, would leave the key alone. No
  one calls this function externally and none of the (since removed)
  callers in OpenSSL rely on this behavior. A NULL check here adds a
  discontinuity at the empty string that seems unnecessary here:
  changing the algorithm without changing the key isn't useful.
  (Note the API doesn't support changing the key without the algorithm.)

Note for reviewing: the representation of ASN1_TYPE is specified
somewhat indirectly. ASN1_TYPE uses the ASN1_ANY ASN1_ITEM, which has
utype V_ASN1_ANY. Then you look at asn1_d2i_ex_primitive and asn1_ex_c2i
which peel off the ASN1_TYPE layer and parse directly into the value
field, with a fixup for NULL. Hopefully we can rework this someday...

Change-Id: I628c4e20f8ea2fd036132242337f4dcac5ba5015
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/46165
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>