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authorMichal Kubecek <mkubecek@suse.cz>2016-12-01 12:55:38 +0100
committerMichal Kubecek <mkubecek@suse.cz>2016-12-01 12:55:38 +0100
commit1beee7a33ca6ddd8e8167d33776ca4e41d7550a6 (patch)
tree56d9ceb2ac3f18fe2c0bd6c94cd197bf417cc83c
parent3f4079f10d4056885f963bb912e7bcaae4cf18aa (diff)
tipc: check minimum bearer MTU (CVE-2016-8632 bsc#1008831).rpm-4.4.21-84
-rw-r--r--net/tipc/bearer.c11
-rw-r--r--net/tipc/bearer.h13
-rw-r--r--net/tipc/udp_media.c5
3 files changed, 27 insertions, 2 deletions
diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index 648f2a67f314..4457c6e9ede8 100644
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -381,6 +381,10 @@ int tipc_enable_l2_media(struct net *net, struct tipc_bearer *b,
dev = dev_get_by_name(net, driver_name);
if (!dev)
return -ENODEV;
+ if (tipc_check_mtu(dev, 0)) {
+ dev_put(dev);
+ return -EINVAL;
+ }
/* Associate TIPC bearer with L2 bearer */
rcu_assign_pointer(b->media_ptr, dev);
@@ -570,14 +574,17 @@ static int tipc_l2_device_event(struct notifier_block *nb, unsigned long evt,
if (!b_ptr)
return NOTIFY_DONE;
- b_ptr->mtu = dev->mtu;
-
switch (evt) {
case NETDEV_CHANGE:
if (netif_carrier_ok(dev))
break;
case NETDEV_GOING_DOWN:
case NETDEV_CHANGEMTU:
+ if (tipc_check_mtu(dev, 0)) {
+ bearer_disable(net, b_ptr);
+ break;
+ }
+ b_ptr->mtu = dev->mtu;
tipc_reset_bearer(net, b_ptr);
break;
case NETDEV_CHANGEADDR:
diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h
index 552185bc4773..6306b6f8f615 100644
--- a/net/tipc/bearer.h
+++ b/net/tipc/bearer.h
@@ -39,6 +39,7 @@
#include "netlink.h"
#include "core.h"
+#include "msg.h"
#include <net/genetlink.h>
#define MAX_MEDIA 3
@@ -61,6 +62,9 @@
#define TIPC_MEDIA_TYPE_IB 2
#define TIPC_MEDIA_TYPE_UDP 3
+/* minimum bearer MTU */
+#define TIPC_MIN_BEARER_MTU (MAX_H_SIZE + INT_H_SIZE)
+
/**
* struct tipc_node_map - set of node identifiers
* @count: # of nodes in set
@@ -226,4 +230,13 @@ void tipc_bearer_xmit(struct net *net, u32 bearer_id,
void tipc_bearer_bc_xmit(struct net *net, u32 bearer_id,
struct sk_buff_head *xmitq);
+/* check if device MTU is sufficient for tipc headers */
+static inline bool tipc_check_mtu(struct net_device *dev, unsigned int reserve)
+{
+ if (dev->mtu >= TIPC_MIN_BEARER_MTU + reserve)
+ return false;
+ netdev_warn(dev, "MTU too low for tipc bearer\n");
+ return true;
+}
+
#endif /* _TIPC_BEARER_H */
diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c
index 70c03271b798..f2aceba37817 100644
--- a/net/tipc/udp_media.c
+++ b/net/tipc/udp_media.c
@@ -381,6 +381,11 @@ static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
udp_conf.use_udp_checksums = false;
ub->ifindex = dev->ifindex;
+ if (tipc_check_mtu(dev, sizeof(struct iphdr) +
+ sizeof(struct udphdr))) {
+ err = -EINVAL;
+ goto err;
+ }
b->mtu = dev->mtu - sizeof(struct iphdr)
- sizeof(struct udphdr);
#if IS_ENABLED(CONFIG_IPV6)