[PATCH 3.16 261/305] bonding: prevent out of bound accesses

Ben Hutchings
2016-08-14T11:20:11Z

From: Eric Dumazet <edumazet@google.com>

commit f87fda00b6ed232a817c655b8d179b48bde8fdbe upstream.

ether_addr_equal_64bits() requires some care about its arguments,
namely that 8 bytes might be read, even if last 2 byte values are not
used.

KASan detected a violation with null_mac_addr and lacpdu_mcast_addr
in bond_3ad.c

Same problem with mac_bcast[] and mac_v6_allmcast[] in bond_alb.c :
Although the 8-byte alignment was there, KASan would detect out
of bound accesses.

Fixes: 815117adaf5b ("bonding: use ether_addr_equal_unaligned for bond addr compare")
Fixes: bb54e58929f3 ("bonding: Verify RX LACPDU has proper dest mac-addr")
Fixes: 885a136c52a8 ("bonding: use compare_ether_addr_64bits() in ALB")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Acked-by: Ding Tianhong <dingtianhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.16:
- Adjust filename
- Drop change to bond_params::ad_actor_system
- Fix one more copy of null_mac_addr to use eth_zero_addr()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/net/bonding/bond_3ad.c | 11 +++++++----
drivers/net/bonding/bond_alb.c | 7 ++-----
drivers/net/bonding/bonding.h | 7 ++++++-
3 files changed, 15 insertions(+), 10 deletions(-)

--- a/drivers/net/bonding/bond_3ad.c
+++ b/drivers/net/bonding/bond_3ad.c
@@ -95,11 +95,14 @@
#define MAC_ADDRESS_EQUAL(A, B) \
ether_addr_equal_64bits((const u8 *)A, (const u8 *)B)

-static struct mac_addr null_mac_addr = { { 0, 0, 0, 0, 0, 0 } };
+static const u8 null_mac_addr[ETH_ALEN + 2] __long_aligned = {
+ 0, 0, 0, 0, 0, 0
+};
static u16 ad_ticks_per_sec;
static const int ad_delta_in_ticks = (AD_TIMER_INTERVAL * HZ) / 1000;

-static const u8 lacpdu_mcast_addr[ETH_ALEN] = MULTICAST_LACPDU_ADDR;
+static const u8 lacpdu_mcast_addr[ETH_ALEN + 2] __long_aligned =
+ MULTICAST_LACPDU_ADDR;

/* ================= main 802.3ad protocol functions ================== */
static int ad_lacpdu_send(struct port *port);
@@ -1614,7 +1617,7 @@ static void ad_clear_agg(struct aggregat
aggregator->is_individual = false;
aggregator->actor_admin_aggregator_key = 0;
aggregator->actor_oper_aggregator_key = 0;
- aggregator->partner_system = null_mac_addr;
+ eth_zero_addr(aggregator->partner_system.mac_addr_value);
aggregator->partner_system_priority = 0;
aggregator->partner_oper_aggregator_key = 0;
aggregator->receive_state = 0;
@@ -1636,7 +1639,7 @@ static void ad_initialize_agg(struct agg
if (aggregator) {
ad_clear_agg(aggregator);

- aggregator->aggregator_mac_address = null_mac_addr;
+ eth_zero_addr(aggregator->aggregator_mac_address.mac_addr_value);
aggregator->aggregator_identifier = 0;
aggregator->slave = NULL;
}
@@ -1671,7 +1674,7 @@ static void ad_initialize_port(struct po
if (port) {
port->actor_port_number = 1;
port->actor_port_priority = 0xff;
- port->actor_system = null_mac_addr;
+ eth_zero_addr(port->actor_system.mac_addr_value);
port->actor_system_priority = 0xffff;
port->actor_port_aggregator_identifier = 0;
port->ntt = false;
--- a/drivers/net/bonding/bond_alb.c
+++ b/drivers/net/bonding/bond_alb.c
@@ -44,13 +44,10 @@

-#ifndef __long_aligned
-#define __long_aligned __attribute__((aligned((sizeof(long)))))
-#endif
-static const u8 mac_bcast[ETH_ALEN] __long_aligned = {
+static const u8 mac_bcast[ETH_ALEN + 2] __long_aligned = {
0xff, 0xff, 0xff, 0xff, 0xff, 0xff
};
-static const u8 mac_v6_allmcast[ETH_ALEN] __long_aligned = {
+static const u8 mac_v6_allmcast[ETH_ALEN + 2] __long_aligned = {
0x33, 0x33, 0x00, 0x00, 0x00, 0x01
};
static const int alb_delta_in_ticks = HZ / ALB_TIMER_TICKS_PER_SEC;
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -41,6 +41,9 @@

#define BOND_DEFAULT_MIIMON 100

+#ifndef __long_aligned
+#define __long_aligned __attribute__((aligned((sizeof(long)))))
+#endif
/*
* Less bad way to call ioctl from within the kernel; this needs to be
* done some other way to get the call out of interrupt context.