netdev - [PATCH net] bonding: fix randomly populated arp target array

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Message-Id: <20170519184646.42572-1-jarod@redhat.com>
Date:   Fri, 19 May 2017 14:46:46 -0400
From:   Jarod Wilson <jarod@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     Jarod Wilson <jarod@...hat.com>,
        Mahesh Bandewar <maheshb@...gle.com>,
        Jay Vosburgh <j.vosburgh@...il.com>,
        Veaceslav Falico <vfalico@...il.com>,
        Andy Gospodarek <andy@...yhouse.net>, netdev@...r.kernel.org,
        stable@...r.kernel.org
Subject: [PATCH net] bonding: fix randomly populated arp target array

In commit dc9c4d0fe023, the arp_target array moved from a static global
to a local variable. By the nature of static globals, the array used to
be initialized to all 0. At present, it's full of random data, which
that gets interpreted as arp_target values, when none have actually been
specified. Systems end up booting with spew along these lines:

[   32.161783] IPv6: ADDRCONF(NETDEV_UP): lacp0: link is not ready
[   32.168475] IPv6: ADDRCONF(NETDEV_UP): lacp0: link is not ready
[   32.175089] 8021q: adding VLAN 0 to HW filter on device lacp0
[   32.193091] IPv6: ADDRCONF(NETDEV_UP): lacp0: link is not ready
[   32.204892] lacp0: Setting MII monitoring interval to 100
[   32.211071] lacp0: Removing ARP target 216.124.228.17
[   32.216824] lacp0: Removing ARP target 218.160.255.255
[   32.222646] lacp0: Removing ARP target 185.170.136.184
[   32.228496] lacp0: invalid ARP target 255.255.255.255 specified for removal
[   32.236294] lacp0: option arp_ip_target: invalid value (-255.255.255.255)
[   32.243987] lacp0: Removing ARP target 56.125.228.17
[   32.249625] lacp0: Removing ARP target 218.160.255.255
[   32.255432] lacp0: Removing ARP target 15.157.233.184
[   32.261165] lacp0: invalid ARP target 255.255.255.255 specified for removal
[   32.268939] lacp0: option arp_ip_target: invalid value (-255.255.255.255)
[   32.276632] lacp0: Removing ARP target 16.0.0.0
[   32.281755] lacp0: Removing ARP target 218.160.255.255
[   32.287567] lacp0: Removing ARP target 72.125.228.17
[   32.293165] lacp0: Removing ARP target 218.160.255.255
[   32.298970] lacp0: Removing ARP target 8.125.228.17
[   32.304458] lacp0: Removing ARP target 218.160.255.255

None of these were actually specified as ARP targets, and the driver does
seem to clean up the mess okay, but it's rather noisy and confusing, leaks
values to userspace, and the 255.255.255.255 spew shows up even when debug
prints are disabled.

The fix: just zero out arp_target at init time.

While we're in here, init arp_all_targets_value in the right place.

Fixes: dc9c4d0fe023 ("bonding: reduce scope of some global variables")
CC: Mahesh Bandewar <maheshb@...gle.com>
CC: Jay Vosburgh <j.vosburgh@...il.com>
CC: Veaceslav Falico <vfalico@...il.com>
CC: Andy Gospodarek <andy@...yhouse.net>
CC: netdev@...r.kernel.org
CC: stable@...r.kernel.org
Signed-off-by: Jarod Wilson <jarod@...hat.com>
---
 drivers/net/bonding/bond_main.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 2be78807fd6e..73313318399c 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -4271,10 +4271,10 @@ static int bond_check_params(struct bond_params *params)
 	int arp_validate_value, fail_over_mac_value, primary_reselect_value, i;
 	struct bond_opt_value newval;
 	const struct bond_opt_value *valptr;
-	int arp_all_targets_value;
+	int arp_all_targets_value = 0;
 	u16 ad_actor_sys_prio = 0;
 	u16 ad_user_port_key = 0;
-	__be32 arp_target[BOND_MAX_ARP_TARGETS];
+	__be32 arp_target[BOND_MAX_ARP_TARGETS] = { 0 };
 	int arp_ip_count;
 	int bond_mode	= BOND_MODE_ROUNDROBIN;
 	int xmit_hashtype = BOND_XMIT_POLICY_LAYER2;
@@ -4501,7 +4501,6 @@ static int bond_check_params(struct bond_params *params)
 		arp_validate_value = 0;
 	}
 
-	arp_all_targets_value = 0;
 	if (arp_all_targets) {
 		bond_opt_initstr(&newval, arp_all_targets);
 		valptr = bond_opt_parse(bond_opt_get(BOND_OPT_ARP_ALL_TARGETS),
-- 
2.12.1