Re: [BUG] staging: rtl8192e: possible null-pointer dereference in rtllib_wx_set_encode()

From: Dan Carpenter
Date: Wed Aug 11 2021 - 03:34:00 EST

On Wed, Aug 11, 2021 at 11:33:57AM +0800, Tuo Li wrote:
> Hello,
> Our static analysis tool finds a possible null-pointer dereference in
> rtllib_wx.c in Linux 5.14.0-rc3:
> The variable (*crypt)->ops is checked in:
> 342:    if (*crypt && (*crypt)->ops && strcmp((*crypt)->ops->name, "R-WEP")
> != 0)
> This indicates that it can be NULL. If so, null-pointer dereferences will
> occur:
> 389:    (*crypt)->ops->set_key()
> 400:    len = (*crypt)->ops->get_key()
> I am not quite sure whether this possible null-pointer dereference is real
> and how to fix it if it is real.
> Any feedback would be appreciated, thanks!
> Reported-by: TOTE Robot <oslab@xxxxxxxxxxxxxxx>

I don't *think* the check is required.

The data in ieee->crypt_info.crypt[idx] is set in rtllib_wx_set_encode()
and rtllib_wx_set_encode_ext() when we do "*crypt = new_crypt;". (The
line is the same in both functions). And in both cases ->ops is

So probably the check should be removed.

On the other hand, I don't know the code very well and it's possible I
missed something.

dan carpenter