Re: [PATCH 1/2] exfat: add dir-entry set checksum validation

[Tetsuhiro Kohada]

Thnak you for your reply.

> > -void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es)
> > +static int exfat_calc_dir_chksum_with_entry_set(struct
> > +exfat_entry_set_cache *es, u16 *chksum)
> >   {
> > -	int chksum_type = CS_DIR_ENTRY, i;
> > -	unsigned short chksum = 0;
> >   	struct exfat_dentry *ep;
> > +	int i;
> >
> > -	for (i = 0; i < es->num_entries; i++) {
> > -		ep = exfat_get_validated_dentry(es, i, TYPE_ALL);
> > -		chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
> > -					     chksum_type);
> > -		chksum_type = CS_DEFAULT;
> > +	ep = container_of(es->de_file, struct exfat_dentry, dentry.file);
> > +	*chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, 0, CS_DIR_ENTRY);
> > +	for (i = 0; i < es->de_file->num_ext; i++) {
> > +		ep = exfat_get_validated_dentry(es, 1 + i, TYPE_SECONDARY);
> > +		if (!ep)
> > +			return -EIO;
> > +		*chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, *chksum, CS_DEFAULT);
> >   	}
> > +	return 0;
> We can return checksum after removing u16 *chksum argument.

I want to do that too!
How should I return the error?

Right now, I found that the type of chksum is not 'u16'.
I'll fix in v2.


> > +}
> > +
> > +void exfat_update_dir_chksum_with_entry_set(struct
> > +exfat_entry_set_cache *es) {
> > +	u16 chksum;
> > +
> > +	exfat_calc_dir_chksum_with_entry_set(es, &chksum);
> >   	es->de_file->checksum = cpu_to_le16(chksum);
> >   	es->modified = true;
> >   }
> > @@ -775,6 +784,7 @@ struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
> >   	struct exfat_entry_set_cache *es;
> >   	struct exfat_dentry *ep;
> >   	struct buffer_head *bh;
> > +	u16 chksum;
> >
> >   	if (p_dir->dir == DIR_DELETED) {
> >   		exfat_err(sb, "access to deleted dentry"); @@ -839,10 +849,10 @@ struct
> > exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
> >   		goto free_es;
> >   	es->de_stream = &ep->dentry.stream;
> >
> > -	for (i = 2; i < es->num_entries; i++) {
> > -		if (!exfat_get_validated_dentry(es, i, TYPE_SECONDARY))
> > -			goto free_es;
> > -	}
> > +	if (max_entries == ES_ALL_ENTRIES &&
> > +	    ((exfat_calc_dir_chksum_with_entry_set(es, &chksum) ||
> > +	      chksum != le16_to_cpu(es->de_file->checksum))))
> Please add error print log if checksum mismatch error happen.

OK.
I'll add in v2.


BR
---
Tetsuhiro Kohada <kohada.t2@xxxxxxxxx>