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Null pointer dereference in bonding driver, kernel 2.6.24

PATCH Chuck Ebbert 2 participants 2 messages Jan 31, 2008

Subsystems (3)
Networking Network drivers Bonding driver
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Chuck Ebbert

author
#0 lore raw

In bond_main.c:

int bond_create(char *name, struct bond_params *params, struct bonding **newbond) {
...
/* Check to see if the bond already exists. */ list_for_each_entry_safe(bond, nxt, &bond_dev_list, bond_list)
if (strnicmp(bond->dev->name, name, IFNAMSIZ) == 0) {
printk(KERN_ERR DRV_NAME
": cannot add bond %s; it already exists\n",

If 'name' is null we get a null dereference in strnicmp()

The code was added in 2.6.24.

Signed-off-by Chuck Ebbert <[email protected]>

---
(not even compile tested)

 drivers/net/bonding/bond_main.c |   20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)
drivers/net/bonding/bond_main.c +11 -9
@@ -4882,15 +4882,17 @@ int bond_create(char *name, struct bond_
 	rtnl_lock();
 	down_write(&bonding_rwsem);
 
-	/* Check to see if the bond already exists. */
-	list_for_each_entry_safe(bond, nxt, &bond_dev_list, bond_list)
-		if (strnicmp(bond->dev->name, name, IFNAMSIZ) == 0) {
-			printk(KERN_ERR DRV_NAME
-			       ": cannot add bond %s; it already exists\n",
-			       name);
-			res = -EPERM;
-			goto out_rtnl;
-		}
+	if (name) {
+		/* Check to see if the bond already exists. */
+		list_for_each_entry_safe(bond, nxt, &bond_dev_list, bond_list)
+			if (strnicmp(bond->dev->name, name, IFNAMSIZ) == 0) {
+				printk(KERN_ERR DRV_NAME
+				       ": cannot add bond %s; it already exists\n",
+				       name);
+				res = -EPERM;
+				goto out_rtnl;
+			}
+	}
 
 	bond_dev = alloc_netdev(sizeof(struct bonding), name ? name : "",
 				ether_setup);
#1 lore raw
Quoted 12 lines · Chuck Ebbert

In bond_main.c:

int bond_create(char *name, struct bond_params *params, struct bonding **newbond) {
...
/* Check to see if the bond already exists. */ list_for_each_entry_safe(bond, nxt, &bond_dev_list, bond_list)
if (strnicmp(bond->dev->name, name, IFNAMSIZ) == 0) {
printk(KERN_ERR DRV_NAME
": cannot add bond %s; it already exists\n",

Quoted 3 lines

If 'name' is null we get a null dereference in strnicmp()

The code was added in 2.6.24.

	This is already fixed in netdev-2.6#upstream.

	-J

---
-Jay Vosburgh, IBM Linux Technology Center, [email protected]