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

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




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