tree 513845885b7b094dd664ae9c5224339833a0534b
parent 1530333b25589ee4d4d52b10e78ee55dd82f6dcd
author David Benjamin <davidben@google.com> 1653332175 -0400
committer Boringssl LUCI CQ <boringssl-scoped@luci-project-accounts.iam.gserviceaccount.com> 1653497319 +0000

Use the correct function types in X509V3_EXT_METHODs.

While C allows function pointer casts, it is UB to call a function with
a different type than its actual type signature. That is, even though
`void f(int *)` and `void g(void *)` have the same ABI, it is UB to
cast `f` to a `void(*)(void *)` and then call it through that pointer.
Clang CFI will try to enforce this rule.

The recent CL to call X509_print in tests revealed that all the i2? and
?2i callbacks in X509V3_EXT_METHODs were implemented with functions of
the wrong type, out of some combination of missing consts and void*
turned into T*.

This CL fixes this. Where the function wasn't exported, or had no
callers, I just fixed the function itself. Where it had extension
callers, I added a wrapper function with a void* type.

I'm not positive whether the wrappers are the right call. On the one
hand, keeping the exported functions as-is is more type-safe and more
OpenSSL-compatible. However, most (but not all) uses of these are in
other code defining X509V3_EXT_METHODs themselves, so the void*
signature is more correct for them too. And the functions have a type
signature meant for X509V3_EXT_METHOD, complete with method pointer.

I've gone with leaving the exported ones as-is for now. Probably the
right answer anyway is to migrate the external callers, of either type
signature.

Change-Id: Ib8f2995cbd890221eaa9ac864a7e553cb6711901
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/52686
Commit-Queue: Bob Beck <bbe@google.com>
Reviewed-by: Bob Beck <bbe@google.com>