From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Fainelli Subject: [PATCH net] net: phy: sfp: Prevent NULL deference of socket_ops Date: Fri, 14 Sep 2018 16:01:31 -0700 Message-ID: <20180914230132.23228-1-f.fainelli@gmail.com> Cc: rmk+kernel@armlinux.org.uk, Florian Fainelli , Andrew Lunn , "David S. Miller" , linux-kernel@vger.kernel.org (open list) To: netdev@vger.kernel.org Return-path: Received: from mail-pf1-f196.google.com ([209.85.210.196]:42425 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725753AbeIOESu (ORCPT ); Sat, 15 Sep 2018 00:18:50 -0400 Sender: netdev-owner@vger.kernel.org List-ID: In case we have specified a SFP and an I2C phandle in the Device Tree, but we somehow failed to look up the I2C adapter (e.g: the driver is not enabled), we will leave dangling socket_ops, and the sfp_bus will still have been registered. We can then observe NULL pointer dereferences while doing ethtool -m: [ 20.218613] Unable to handle kernel NULL pointer dereference at virtual address 00000008 [ 20.226977] pgd = (ptrval) [ 20.229785] [00000008] *pgd=7c400831, *pte=00000000, *ppte=00000000 [ 20.236274] Internal error: Oops: 17 [#1] SMP ARM [ 20.241122] Modules linked in: [ 20.244278] CPU: 0 PID: 1480 Comm: ethtool Not tainted 4.19.0-rc3 #138 [ 20.251013] Hardware name: Broadcom Northstar Plus SoC [ 20.256316] PC is at sfp_get_module_info+0x8/0x10 [ 20.261172] LR is at dev_ethtool+0x218c/0x2afc Specifically guard against that. Fixes: ce0aa27ff3f6 ("sfp: add sfp-bus to bridge between network devices and sfp cages") Signed-off-by: Florian Fainelli --- drivers/net/phy/sfp-bus.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/net/phy/sfp-bus.c b/drivers/net/phy/sfp-bus.c index 740655261e5b..9465be501372 100644 --- a/drivers/net/phy/sfp-bus.c +++ b/drivers/net/phy/sfp-bus.c @@ -378,6 +378,9 @@ static void sfp_unregister_bus(struct sfp_bus *bus) */ int sfp_get_module_info(struct sfp_bus *bus, struct ethtool_modinfo *modinfo) { + if (!bus->socket_ops) + return -EOPNOTSUPP; + return bus->socket_ops->module_info(bus->sfp, modinfo); } EXPORT_SYMBOL_GPL(sfp_get_module_info); @@ -396,6 +399,9 @@ EXPORT_SYMBOL_GPL(sfp_get_module_info); int sfp_get_module_eeprom(struct sfp_bus *bus, struct ethtool_eeprom *ee, u8 *data) { + if (!bus->socket_ops) + return -EOPNOTSUPP; + return bus->socket_ops->module_eeprom(bus->sfp, ee, data); } EXPORT_SYMBOL_GPL(sfp_get_module_eeprom); -- 2.17.1