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From: Julia Lawall <julia@diku.dk>
To: pantelis.antoniou@gmail.com, vbordug@ru.mvista.com,
	linuxppc-dev@ozlabs.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH 4/6] drivers/net/fs_enet: remove null pointer dereference
Date: Mon, 12 May 2008 15:38:26 +0200 (CEST)	[thread overview]
Message-ID: <Pine.LNX.4.64.0805121537590.3694@ask.diku.dk> (raw)

From: Julia Lawall <julia@diku.dk>

The following code appears in the function fs_init_instance in the file drivers/net/fs_enet/fs_enet-main.c.

	if (fep->ops == NULL) {
		printk(KERN_ERR DRV_MODULE_NAME
		       ": %s No matching ops found (%d).\n",
		       ndev->name, fpi->fs_no);
		err = -EINVAL;
		goto err;
	}

This code implies that at the point of err, fep->ops can be NULL, so an
extra test is needed before dereferencing this value.


This problem was found using the following semantic match
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
expression E, E1;
identifier f;
statement S1,S2,S3;
@@

* if (E == NULL)
{
  ... when != if (E == NULL) S1 else S2
      when != E = E1
* E->f
  ... when any
  return ...;
}
else S3
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>

---

diff -u -p a/drivers/net/fs_enet/fs_enet-main.c b/drivers/net/fs_enet/fs_enet-main.c
--- a/drivers/net/fs_enet/fs_enet-main.c	2008-04-27 11:41:11.000000000 +0200
+++ b/drivers/net/fs_enet/fs_enet-main.c	2008-05-12 09:41:52.000000000 +0200
@@ -1093,7 +1093,7 @@ err:
 		if (registered)
 			unregister_netdev(ndev);
 
-		if (fep != NULL) {
+		if (fep && fep->ops) {
 			(*fep->ops->free_bd)(ndev);
 			(*fep->ops->cleanup_data)(ndev);
 		}

             reply	other threads:[~2008-05-12 14:12 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-05-12 13:38 Julia Lawall [this message]
2008-05-12 15:37 ` [PATCH 4/6] drivers/net/fs_enet: remove null pointer dereference Vitaly Bordug
2008-05-12 16:51 ` Francois Romieu
2008-05-12 17:22   ` Scott Wood
2008-05-22 10:27 ` Jeff Garzik

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