netdev - kernel BUG at drivers/net/phy/mdio

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <m3ej07zg85.fsf@maximus.localdomain>
Date:	Wed, 17 Dec 2008 03:29:46 +0100
From:	Krzysztof Halasa <khc@...waw.pl>
To:	Lennert Buytenhek <buytenh@...tstofly.org>
Cc:	David Miller <davem@...emloft.net>, <netdev@...r.kernel.org>
Subject: kernel BUG at drivers/net/phy/mdio_bus.c:165!

kernel BUG at drivers/net/phy/mdio_bus.c:165!
Unable to handle kernel NULL pointer dereference at virtual address 00000000

How?

mdiobus_alloc() sets bus->state = MDIOBUS_ALLOCATED.

mdiobus_register() sets bus->state = MDIOBUS_REGISTERED but then can
   fail (mdiobus_scan()) returning an error to the caller.

The caller aborts correctly with mdiobus_free() which does:
        if (bus->state == MDIOBUS_ALLOCATED) {
                kfree(bus);
                return;
        }

        BUG_ON(bus->state != MDIOBUS_UNREGISTERED);

Signed-off-by: Krzysztof Halasa <khc@...waw.pl>

--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -105,8 +105,6 @@ int mdiobus_register(struct mii_bus *bus)
 		return -EINVAL;
 	}

-	bus->state = MDIOBUS_REGISTERED;
-
 	mutex_init(&bus->mdio_lock);

 	if (bus->reset)
@@ -123,6 +121,9 @@ int mdiobus_register(struct mii_bus *bus)
 		}
 	}

+	if (!err)
+		bus->state = MDIOBUS_REGISTERED;
+
 	pr_info("%s: probed\n", bus->name);

 	return err;

-- 
Krzysztof Halasa
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html