[Bug 57656] New: CryptMsgGetParam() with CMSG_SIGNER_AUTH_ATTR_PARAM/CMSG_SIGNER_UNAUTH_ATTR_PARAM returns success with 0 buffer size

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=57656

Bug ID: 57656
           Summary: CryptMsgGetParam() with
                    CMSG_SIGNER_AUTH_ATTR_PARAM/CMSG_SIGNER_UNAUTH_ATTR_PA
                    RAM returns success with 0 buffer size
           Product: Wine
           Version: 10.0-rc5
          Hardware: x86-64
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: crypt32
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

This is currently triggered by wintrust tests from test_wintrust_digest(). The
issue is that GetParam returns TRUE when there is no attributes to return. That
leads to malloc(0) and then attempt to read attributes from that.

I don't know how to write a proper test for this at crypt32 side, so filing a
bug instead.