Re: 2.6.18-mm2 - oops in cache_alloc_refill()

[Jean Tourrilhes <jt@hpl.hp.com>]

On Fri, Sep 29, 2006 at 06:20:08PM -0700, Andrew Morton wrote:
> On Fri, 29 Sep 2006 20:01:54 -0400
> > 
> > % grep ioctl /tmp/foo2 | sort -u | more
> > ioctl(13, SIOCGIWESSID, 0xbfbcdb9c)     = 0
> > ioctl(13, SIOCGIWRANGE, 0xbfbcdbdc)     = 0
> > ioctl(13, SIOCGIWRATE, 0xbfbcdbbc)      = 0
> 
> Yes.  The main thing which those WE-21 patches do is to shorten the size of
> various buffers which are used in wireless ioctls.

	Ok, I've found it. Actually, I feel ashamed, as it is a fairly
classical buffer overflow, we put one extra char in a buffer. Now, I
don't understand why it did not blow up on my box ;-)
	New patch. I think it is right, but I would not mind Pavel to
have a look at it. On my box it does not make thing worse.
	Valdis : would you mind trying if this patch fix the problem
you are seeing with WE-21 ? If it fixes it, I'll send it to John...
	Have fun...

	Jean

P.S. : I'll audit the other wireless drivers for the same thing.

-------------------------------------------------

diff -u -p linux/drivers/net/wireless/orinoco.j1.c linux/drivers/net/wireless/orinoco.c
--- linux/drivers/net/wireless/orinoco.j1.c	2006-10-02 10:15:41.000000000 -0700
+++ linux/drivers/net/wireless/orinoco.c	2006-10-02 10:39:20.000000000 -0700
@@ -2456,6 +2456,7 @@ void free_orinocodev(struct net_device *
 /* Wireless extensions                                              */
 /********************************************************************/
 
+/* Return : < 0 -> error code ; >= 0 -> length */
 static int orinoco_hw_get_essid(struct orinoco_private *priv, int *active,
 				char buf[IW_ESSID_MAX_SIZE+1])
 {
@@ -2500,9 +2501,9 @@ static int orinoco_hw_get_essid(struct o
 	len = le16_to_cpu(essidbuf.len);
 	BUG_ON(len > IW_ESSID_MAX_SIZE);
 
-	memset(buf, 0, IW_ESSID_MAX_SIZE+1);
+	memset(buf, 0, IW_ESSID_MAX_SIZE);
 	memcpy(buf, p, len);
-	buf[len] = '\0';
+	err = len;
 
  fail_unlock:
 	orinoco_unlock(priv, &flags);
@@ -3026,17 +3027,18 @@ static int orinoco_ioctl_getessid(struct
 
 	if (netif_running(dev)) {
 		err = orinoco_hw_get_essid(priv, &active, essidbuf);
-		if (err)
+		if (err < 0)
 			return err;
+		erq->length = err;
 	} else {
 		if (orinoco_lock(priv, &flags) != 0)
 			return -EBUSY;
-		memcpy(essidbuf, priv->desired_essid, IW_ESSID_MAX_SIZE + 1);
+		memcpy(essidbuf, priv->desired_essid, IW_ESSID_MAX_SIZE);
+		erq->length = strlen(priv->desired_essid);
 		orinoco_unlock(priv, &flags);
 	}
 
 	erq->flags = 1;
-	erq->length = strlen(essidbuf);
 
 	return 0;
 }
@@ -3074,10 +3076,10 @@ static int orinoco_ioctl_getnick(struct 
 	if (orinoco_lock(priv, &flags) != 0)
 		return -EBUSY;
 
-	memcpy(nickbuf, priv->nick, IW_ESSID_MAX_SIZE+1);
+	memcpy(nickbuf, priv->nick, IW_ESSID_MAX_SIZE);
 	orinoco_unlock(priv, &flags);
 
-	nrq->length = strlen(nickbuf);
+	nrq->length = strlen(priv->nick);
 
 	return 0;
 }
-
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