Re: [PATCH v3] exfat: integrates dir-entry getting and validation

[Tetsuhiro Kohada]

On 2020/08/26 10:03, Namjae Jeon wrote:
> > Second: Range validation and type validation should not be separated.
> > When I started making this patch, I intended to add only range validation.
> > However, after the caller gets the ep, the type validation follows.
> > Get ep, null check of ep (= range verification), type verification is a series of procedures.
> > There would be no reason to keep them independent anymore.
> > Range and type validation is enforced when the caller uses ep.
> You can add a validate flags as argument of exfat_get_dentry_set(), e.g. none, basic and strict.
> none : only range validation.
> basic : range + type validation.
> strict : range + type + checksum and name length, etc.

Currently, various types of verification will not be needed.
Let's add it when we need it.
>   
> > > -	/* validiate cached dentries */
> > > -	for (i = 1; i < num_entries; i++) {
> > > -		ep = exfat_get_dentry_cached(es, i);
> > > -		if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
> > > +	ep = exfat_get_dentry_cached(es, ENTRY_STREAM);
> > > +	if (!ep || ep->type != EXFAT_STREAM)
> > > +		goto free_es;
> > > +	es->de[ENTRY_STREAM] = ep;
> >
> > The value contained in stream-ext dir-entry should not be used before validating the EntrySet checksum.
> > So I would insert EntrySet checksum validation here.
> > In that case, the checksum verification loop would be followed by the TYPE_NAME verification loop, can
> > you acceptable?
> Yes. That would be great.

OK.
I'll add TYPE_NAME verification after checksum verification, in next patch.
However, I think it is enough to validate TYPE_NAME when extracting name.
Could you please tell me why you think you need TYPE_NAME validation here?


BR
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Tetsuhiro Kohada <kohada.t2@xxxxxxxxx>
>