Re: [PATCH 06/13] pkcs5: Add the PKCS#12 KDF

[Denis Kenzior <denkenz@gmail.com>]

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Hi Andrew,

On 12/10/20 1:31 PM, Andrew Zaborowski wrote:
> Add the key derivation algorithm used with PKCS#12 to pkcs5.c so that it
> can be found together with the two PKCS#5 KDFs, and so that it can also
> be used when parsing of the PKCS#12 AlgorithmIdentifiers in the next
> commit.  This KDF is not recommended for new uses.
> ---
>   ell/pkcs5-private.h |  12 ++++
>   ell/pkcs5.c         | 146 ++++++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 158 insertions(+)
> 

<snip>

> +static bool utf8_to_bmpstring(const char *utf, uint8_t *out_buf,
> +				unsigned int *out_len)
> +{
> +	unsigned int n;
> +	int utflen;
> +	wchar_t cp;
> +	uint16_t *ptr = (uint16_t *) out_buf;
> +
> +	for (n = strlen(utf); n; n -= utflen, utf += utflen) {
> +		if ((utflen = l_utf8_get_codepoint(utf, n, &cp)) <= 0 ||
> +				cp > 0xffff)
> +			return false;

So is this just a UCS2BE conversion?  If so, then using l_utf8_to_ucs2be might 
be clearer.

> +
> +		*ptr++ = L_CPU_TO_BE16(cp);
> +	}
> +
> +	*ptr++ = 0;
> +	*out_len = (uint8_t *) ptr - out_buf;
> +	return true;
> +}
> +

Regards,
-Denis