Commit 8503bd8c authored Sep 26, 2009 by Arjan van de Ven Committed by John W. Linville Sep 28, 2009

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 <arjan@linux.intel.com>
Cc: linux-wireless@vger.kernel.org
Signed-off-by: John W. Linville <linville@tuxdriver.com>

parent 0ff71613

net/wireless/wext.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -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;

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