static int do_readpage(struct page *page)
{
	void *addr;
	int err = 0, i;
	unsigned int block, beyond;
	struct ubifs_data_node *dn;
	struct inode *inode = page->mapping->host;
	loff_t i_size = i_size_read(inode);

	dbg_gen("ino %lu, pg %lu, i_size %lld, flags %#lx",
		inode->i_ino, page->index, i_size, page->flags);
	ubifs_assert(!PageChecked(page));
	ubifs_assert(!PagePrivate(page));

	addr = kmap(page);

	block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT;
	beyond = (i_size + UBIFS_BLOCK_SIZE - 1) >> UBIFS_BLOCK_SHIFT;
	if (block >= beyond) {
		/* Reading beyond inode */
		SetPageChecked(page);
		memset(addr, 0, PAGE_CACHE_SIZE);
		goto out;
	}

	dn = kmalloc(UBIFS_MAX_DATA_NODE_SZ, GFP_NOFS);
	if (!dn) {
		err = -ENOMEM;
		goto error;
	}

	i = 0;
	while (1) {
		int ret;

		if (block >= beyond) {
			/* Reading beyond inode */
			err = -ENOENT;
			memset(addr, 0, UBIFS_BLOCK_SIZE);
		} else {
			ret = read_block(inode, addr, block, dn);
			if (ret) {
				err = ret;
				if (err != -ENOENT)
					break;
			} else if (block + 1 == beyond) {
				int dlen = le32_to_cpu(dn->size);
				int ilen = i_size & (UBIFS_BLOCK_SIZE - 1);

				if (ilen && ilen < dlen)
					memset(addr + ilen, 0, dlen - ilen);
			}
		}
		if (++i >= UBIFS_BLOCKS_PER_PAGE)
			break;
		block += 1;
		addr += UBIFS_BLOCK_SIZE;
	}
	if (err) {
		if (err == -ENOENT) {
			/* Not found, so it must be a hole */
			SetPageChecked(page);
			dbg_gen("hole");
			goto out_free;
		}
		ubifs_err("cannot read page %lu of inode %lu, error %d",
			  page->index, inode->i_ino, err);
		goto error;
	}

out_free:
	kfree(dn);
out:
	SetPageUptodate(page);
	ClearPageError(page);
	flush_dcache_page(page);
	kunmap(page);
	return 0;

error:
	kfree(dn);
	ClearPageUptodate(page);
	SetPageError(page);
	flush_dcache_page(page);
	kunmap(page);
	return err;
}

This category addresses vulnerabilities caused by flawed access control mechanisms, where incorrect permission settings allow unauthorized users to access restricted resources.