On Mon, Oct 26, 2015 at 08:41:06PM +0700, Ivan Safonov wrote:
> On 10/26/2015 04:06 PM, Dan Carpenter wrote:
> >On Sat, Oct 24, 2015 at 08:42:29PM +0700, Ivan Safonov wrote:
> >>diff --git a/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c 
> >>b/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c
> >>index 98bdc95..735e24b 100644
> >>--- a/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c
> >>+++ b/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c
> >>@@ -2669,7 +2669,7 @@ static int rtw_get_sta_wpaie(struct net_device *dev, 
> >>struct ieee_param *param)
> >>                    int copy_len;
> >>                    wpa_ie_len = psta->wpa_ie[1];
> >>-                   copy_len = ((wpa_ie_len+2) > sizeof(psta->wpa_ie)) ? 
> >>(sizeof(psta->wpa_ie)) : (wpa_ie_len+2);
> >>+                   copy_len = min(wpa_ie_len + 2, 
> >>(int)sizeof(psta->wpa_ie));
> >>                    param->u.wpa_ie.len = copy_len;
> >>                    memcpy(param->u.wpa_ie.reserved, psta->wpa_ie, 
> >> copy_len);
> >
> >In the original code if "wpa_ie_len + 2" was negative then copy_len is
> >sizeof(psta->wpa_ie), but in the new code copy_len is a negative
> >number and the memcpy() will corrupt memory and crash the system.
> >
> >regards,
> >dan carpenter
> 
> It is quite unexpected for me.
> 
> I proceeded from the assumption that psta->wpa_ie[1] is u8 and
> wpa_ie_len (and wpa_ie_len + 2) is always greater than zero and less
> then INT_MAX.
>

Ah.  Yes.  You're right.  psta->wpa_ie[] is u8.  My mistake.  Sorry for
that.

regards,
dan carpenter

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