From mboxrd@z Thu Jan 1 00:00:00 1970 From: Larry Finger Date: Fri, 07 Feb 2014 02:51:30 +0000 Subject: Re: [patch 2/2] staging: r8188eu: overflow in rtw_p2p_get_go_device_address() Message-Id: <52F44A32.7040102@lwfinger.net> List-Id: References: <20140203223835.GB28874@elgon.mountain> In-Reply-To: <20140203223835.GB28874@elgon.mountain> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kernel-janitors@vger.kernel.org On 02/03/2014 04:38 PM, Dan Carpenter wrote: > The go_devadd_str[] array is two characters too small to hold the > address so we corrupt memory. > > I've changed the user space API slightly and I don't have a way to test > if this breaks anything. In the original code we truncated away the > last digit of the address and the NUL terminator so it was already a bit > broken. > > Signed-off-by: Dan Carpenter Nothing seems to be broken. Acked-by: Larry Finger Larry > > diff --git a/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c b/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c > index dec992569476..4ad80ae1067f 100644 > --- a/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c > +++ b/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c > @@ -3164,9 +3164,7 @@ static int rtw_p2p_get_go_device_address(struct net_device *dev, > u8 *p2pie; > uint p2pielen = 0, attr_contentlen = 0; > u8 attr_content[100] = {0x00}; > - > - u8 go_devadd_str[17 + 10] = {0x00}; > - /* +10 is for the str "go_devadd =", we have to clear it at wrqu->data.pointer */ > + u8 go_devadd_str[17 + 12] = {}; > > /* Commented by Albert 20121209 */ > /* The input data is the GO's interface address which the application wants to know its device address. */ > @@ -3223,12 +3221,12 @@ static int rtw_p2p_get_go_device_address(struct net_device *dev, > spin_unlock_bh(&pmlmepriv->scanned_queue.lock); > > if (!blnMatch) > - sprintf(go_devadd_str, "\n\ndev_add = NULL"); > + snprintf(go_devadd_str, sizeof(go_devadd_str), "\n\ndev_add = NULL"); > else > - sprintf(go_devadd_str, "\n\ndev_add =%.2X:%.2X:%.2X:%.2X:%.2X:%.2X", > + snprintf(go_devadd_str, sizeof(go_devadd_str), "\n\ndev_add =%.2X:%.2X:%.2X:%.2X:%.2X:%.2X", > attr_content[0], attr_content[1], attr_content[2], attr_content[3], attr_content[4], attr_content[5]); > > - if (copy_to_user(wrqu->data.pointer, go_devadd_str, 10 + 17)) > + if (copy_to_user(wrqu->data.pointer, go_devadd_str, sizeof(go_devadd_str))) > return -EFAULT; > return ret; > } >