[openssl-project] Help deciding on PR 6341 (facilitate reading PKCS#12 objects in OSSL_STORE)

[Viktor Dukhovni]

> On Jun 6, 2018, at 12:52 PM, David Benjamin <davidben at google.com> wrote:
> 
> Oh, I didn't realize that document existed. Although it doesn't say that it is overriding the BMPString restrictions. It says it "does not add any further restrictions to the input passwords of these methods, however it is RECOMMENDED to use (big-endian) UTF-16 NFC form". That reads to me as saying you should use UTF-16 NFC form, but only the subset that still satisfies the existing BMPString restrictions. It even recommends that "applications which restricted the MacData password to BMPString set" fail in some cases.
> 
> If the intent was otherwise, probably worth some rewording.

The point is that instead of failing we should use UTF-16 for non-BMP code points.
Worst case we'll still fail.  We can document a warning that passwords outside
the BMP are non-portable.  The responsibility for ensuring NFC form will be placed
on the application feeding us the UTF-8 data.  We should just convert from UTF-8 to
UTF-16.

I don't read the draft as forbidding non-BMP UTF-16.  The two agree on the UCS-2
subset of UTF-16 (i.e. the BMP code points).  If the intent is to forbind non-BMP
passwords, we should ask the authors to change that, with a portability warning.
Such passwords might not work everywhere, but forbidding them is unwise.

-- 
	Viktor.