From: Arjan van de Ven Date: Sat, 26 Sep 2009 18:51:14 +0000 (+0200) Subject: wext: Add bound checks for copy_from_user X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=8503bd8c7dc6f82ec2de9d05e0a476e6ca5adc8b;p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.git wext: Add bound checks for copy_from_user The wireless extensions have a copy_from_user to a local stack array "essid", but both me and gcc have failed to find where the bounds for this copy are located in the code. This patch adds some basic sanity checks for the copy length to make sure that we don't overflow the stack buffer. Signed-off-by: Arjan van de Ven Cc: linux-wireless@vger.kernel.org Signed-off-by: John W. Linville --- diff --git a/net/wireless/wext.c b/net/wireless/wext.c index 5b4a0cee4418..ac4ac26b53ce 100644 --- a/net/wireless/wext.c +++ b/net/wireless/wext.c @@ -773,10 +773,13 @@ static int ioctl_standard_iw_point(struct iw_point *iwp, unsigned int cmd, essid_compat = 1; else if (IW_IS_SET(cmd) && (iwp->length != 0)) { char essid[IW_ESSID_MAX_SIZE + 1]; + unsigned int len; + len = iwp->length * descr->token_size; - err = copy_from_user(essid, iwp->pointer, - iwp->length * - descr->token_size); + if (len > IW_ESSID_MAX_SIZE) + return -EFAULT; + + err = copy_from_user(essid, iwp->pointer, len); if (err) return -EFAULT;