Re: [Qemu-devel] [PATCH WIP 01/30] crypto: add QCryptoSecret object class for password/key handling

[Markus Armbruster]

"Daniel P. Berrange" <address@hidden> writes:

> On Fri, Nov 20, 2015 at 03:09:25PM -0700, Eric Blake wrote:
>> On 11/20/2015 11:04 AM, Daniel P. Berrange wrote:
>> > +
>> > +static const char *base64_valid_chars =
>> > +    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
>> > +
>> > +static int
>> > +qcrypto_secret_validate_base64(const uint8_t *input,
>> > +                               size_t inputlen,
>> > +                               Error **errp)
>> 
>> Don't we already have base64 utility methods available?
>
> We normally use glib,  g_base64_encode/decode. Unfortunately the
> decode method doesn't provide any usefull error reporting facility.
> It just silently skips any characters that are outside the valid
> set.  So the only way I could get any kind of sensible error report
> was to do this validation myself against the set of permitted base64
> characters.

Yes.  Same problem elsewhere, e.g. ringbuf-write.  qapi-schema.json:

#          - base64: data must be base64 encoded text.  Its binary
#            decoding gets written.
#            Bug: invalid base64 is currently not rejected.
#            Whitespace *is* invalid.

This suggests that we shouldn't bury this in crypto/, but instead add it
to util/.

A replacement for g_base64_decode() could be easier to use than a
checker function to use in addition to g_base64_decode(),

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