Re: add Packet hub driver for Topcliff Platform controller hub

Tomoya MORINAGA
2013-01-08T10:30:36Z

Hi Dan,

On Mon, Jan 7, 2013 at 6:02 PM, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> The patch cf4ece53460c: "add Packet hub driver for Topcliff Platform
> controller hub" from Sep 1, 2010, leads to the following warning:
> drivers/misc/pch_phub.c:596 pch_phub_bin_write()
> error: buffer overflow 'buf' 4096 <= 15359
>
> Sorry my question is about an old patch. Smatch complains because we
> only pass a PAGE_SIZE buffer to sysfs files so the test for
> "if (count > PCH_PHUB_OROM_SIZE) {" makes it think we are overflowing.
> In fact, count is never more than 4096 so there is no overflow, but I
> also think that it means only the first 4096 bytes of the firmware gets
> updated.
>
> drivers/misc/pch_phub.c
> 560 static ssize_t pch_phub_bin_write(struct file *filp, struct kobject *kobj,
> 561 struct bin_attribute *attr,
> 562 char *buf, loff_t off, size_t count)
> 563 {
> 564 int err;
> 565 unsigned int addr_offset;
> 566 int ret;
> 567 ssize_t rom_size;
> 568 struct pch_phub_reg *chip =
> 569 dev_get_drvdata(container_of(kobj, struct device, kobj));
> 570
> 571 ret = mutex_lock_interruptible(&pch_phub_mutex);
> 572 if (ret)
> 573 return -ERESTARTSYS;
> 574
> 575 if (off > PCH_PHUB_OROM_SIZE) {
> 576 addr_offset = 0;
> 577 goto return_ok;
> 578 }
> 579 if (count > PCH_PHUB_OROM_SIZE) {
> ^^^^^^^^^^^^^^^^^^
> This is 15359.
>
> 580 addr_offset = 0;
> 581 goto return_ok;
> 582 }
> 583
> 584 chip->pch_phub_extrom_base_address = pci_map_rom(chip->pdev, &rom_size);
> 585 if (!chip->pch_phub_extrom_base_address) {
> 586 err = -ENOMEM;
> 587 goto exrom_map_err;
> 588 }
> 589
> 590 for (addr_offset = 0; addr_offset < count; addr_offset++) {
> 591 if (PCH_PHUB_OROM_SIZE < off + addr_offset)
> 592 goto return_ok;
> 593
> 594 ret = pch_phub_write_serial_rom(chip,
> 595 chip->pch_opt_rom_start_address + addr_offset + off,
> 596 buf[addr_offset]);
> ^^^^^^^^^^^^^^^^
> Smatch complains because "buf" is only 4096 bytes.
>

I can understand your saying.

You mean just delete the following condition ?

579 if (count > PCH_PHUB_OROM_SIZE) {

Thanks.

--
ROHM Co., Ltd.
tomoya