2011-09-21 07:07:12

by Dan Carpenter

Subject: re: wl12xx: support up to 8 stations in AP-mode

Hi Arik,

Smatch complains about c47e8229fa56 "wl12xx: support up to 8 stations
in AP-mode"

drivers/net/wireless/wl12xx/main.c +832 wl12xx_irq_update_links_status(22)
error: buffer overflow 'status->tx_lnk_free_pkts' 8 <= 10

828 for (hlid = WL1271_AP_STA_HLID_START; hlid < AP_MAX_LINKS; hlid++) {
^^^^^^^^^^^^
We increased this to 11.

829 if (!wl1271_is_active_sta(wl, hlid))
830 continue;
831
832 cnt = status->tx_lnk_free_pkts[hlid] -
^^^^^^^^^^^^^^^^^^^^^^

But the ->tx_lnk_free_pkts[] array still only has 8 elements so we're
reading past the end of the array.

833 wl->links[hlid].prev_freed_pkts;
834
835 wl->links[hlid].prev_freed_pkts =
836 status->tx_lnk_free_pkts[hlid];
837 wl->links[hlid].allocated_pkts -= cnt;
838
839 wl12xx_irq_ps_regulate_link(wl, hlid,
840 wl->links[hlid].allocated_pkts);
841 }

regards,
dan carpenter

2011-09-22 05:37:26

by Arik Nemtsov

Subject: Re: wl12xx: support up to 8 stations in AP-mode

On Wed, Sep 21, 2011 at 10:25, Luciano Coelho <[email protected]> wrote:
> On Wed, 2011-09-21 at 00:05 -0700, Dan Carpenter wrote:
>> Hi Arik,
>>
>> Smatch complains about c47e8229fa56 "wl12xx: support up to 8 stations
>> in AP-mode"
>>
>> drivers/net/wireless/wl12xx/main.c +832 wl12xx_irq_update_links_status(22)
>> ? ? ? error: buffer overflow 'status->tx_lnk_free_pkts' 8 <= 10
>>
>> ? ?828 ? ? ? ? ?for (hlid = WL1271_AP_STA_HLID_START; hlid < AP_MAX_LINKS; hlid++) {
>> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?^^^^^^^^^^^^

Again, good catch there Dan. We'll verify the fix internally before
releasing it (as it changes the host-fw interface).
I'll also add a BUILD_BUG_ON so this won't happen again.

Arik

2011-09-21 07:25:11

by Luciano Coelho

Subject: re: wl12xx: support up to 8 stations in AP-mode

On Wed, 2011-09-21 at 00:05 -0700, Dan Carpenter wrote:
> Hi Arik,
>
> Smatch complains about c47e8229fa56 "wl12xx: support up to 8 stations
> in AP-mode"
>
> drivers/net/wireless/wl12xx/main.c +832 wl12xx_irq_update_links_status(22)
> error: buffer overflow 'status->tx_lnk_free_pkts' 8 <= 10
>
> 828 for (hlid = WL1271_AP_STA_HLID_START; hlid < AP_MAX_LINKS; hlid++) {
> ^^^^^^^^^^^^
> We increased this to 11.
>
> 829 if (!wl1271_is_active_sta(wl, hlid))
> 830 continue;
> 831
> 832 cnt = status->tx_lnk_free_pkts[hlid] -
> ^^^^^^^^^^^^^^^^^^^^^^
>
> But the ->tx_lnk_free_pkts[] array still only has 8 elements so we're
> reading past the end of the array.
>
> 833 wl->links[hlid].prev_freed_pkts;
> 834
> 835 wl->links[hlid].prev_freed_pkts =
> 836 status->tx_lnk_free_pkts[hlid];
> 837 wl->links[hlid].allocated_pkts -= cnt;
> 838
> 839 wl12xx_irq_ps_regulate_link(wl, hlid,
> 840 wl->links[hlid].allocated_pkts);
> 841 }

Good catch, Dan! Thanks for checking this.

I checked our new firmware API and it seems that the wl12xx_fw_status
structure has changed. Now, WL12XX_MAX_LINKS, should be 12 instead of
8.

Arik, can you verify this and send a fix patch?


--
Cheers,
Luca.