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SubjectRe: [PATCH 1/2] exfat: add dir-entry set checksum validation
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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@gmail.com>

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