int isofs_get_blocks(struct inode *inode, sector_t iblock,
		     struct buffer_head **bh, unsigned long nblocks)
{
	unsigned long b_off = iblock;
	unsigned offset, sect_size;
	unsigned int firstext;
	unsigned long nextblk, nextoff;
	int section, rv, error;
	struct iso_inode_info *ei = ISOFS_I(inode);

	error = -EIO;
	rv = 0;
	if (iblock != b_off) {
		printk(KERN_DEBUG "%s: block number too large\n", __func__);
		goto abort;
	}


	offset = 0;
	firstext = ei->i_first_extent;
	sect_size = ei->i_section_size >> ISOFS_BUFFER_BITS(inode);
	nextblk = ei->i_next_section_block;
	nextoff = ei->i_next_section_offset;
	section = 0;

	while (nblocks) {
		/* If we are *way* beyond the end of the file, print a message.
		 * Access beyond the end of the file up to the next page boundary
		 * is normal, however because of the way the page cache works.
		 * In this case, we just return 0 so that we can properly fill
		 * the page with useless information without generating any
		 * I/O errors.
		 */
		if (b_off > ((inode->i_size + PAGE_CACHE_SIZE - 1) >> ISOFS_BUFFER_BITS(inode))) {
			printk(KERN_DEBUG "%s: block >= EOF (%lu, %llu)\n",
				__func__, b_off,
				(unsigned long long)inode->i_size);
			goto abort;
		}

		/* On the last section, nextblk == 0, section size is likely to
		 * exceed sect_size by a partial block, and access beyond the
		 * end of the file will reach beyond the section size, too.
		 */
		while (nextblk && (b_off >= (offset + sect_size))) {
			struct inode *ninode;

			offset += sect_size;
			ninode = isofs_iget(inode->i_sb, nextblk, nextoff);
			if (IS_ERR(ninode)) {
				error = PTR_ERR(ninode);
				goto abort;
			}
			firstext  = ISOFS_I(ninode)->i_first_extent;
			sect_size = ISOFS_I(ninode)->i_section_size >> ISOFS_BUFFER_BITS(ninode);
			nextblk   = ISOFS_I(ninode)->i_next_section_block;
			nextoff   = ISOFS_I(ninode)->i_next_section_offset;
			iput(ninode);

			if (++section > 100) {
				printk(KERN_DEBUG "%s: More than 100 file sections ?!?"
					" aborting...\n", __func__);
				printk(KERN_DEBUG "%s: block=%lu firstext=%u sect_size=%u "
					"nextblk=%lu nextoff=%lu\n", __func__,
					b_off, firstext, (unsigned) sect_size,
					nextblk, nextoff);
				goto abort;
			}
		}

		if (*bh) {
			map_bh(*bh, inode->i_sb, firstext + b_off - offset);
		} else {
			*bh = sb_getblk(inode->i_sb, firstext+b_off-offset);
			if (!*bh)
				goto abort;
		}
		bh++;	/* Next buffer head */
		b_off++;	/* Next buffer offset */
		nblocks--;
		rv++;
	}

	error = 0;
abort:
	return rv != 0 ? rv : error;
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.