path: root/drivers/net/xen-netback/netback.c
diff options
authorWei Liu <wei.liu2@citrix.com>2014-04-01 12:46:12 +0100
committerDavid S. Miller <davem@davemloft.net>2014-04-01 16:25:51 -0400
commite9d8b2c2968499c1f96563e6522c56958d5a1d0d (patch)
treee179e6438f2057a441b6b3e263923d11018a2b2c /drivers/net/xen-netback/netback.c
parentnet/mlx4: Set proper build dependancy with vxlan (diff)
xen-netback: disable rogue vif in kthread context
When netback discovers frontend is sending malformed packet it will disables the interface which serves that frontend. However disabling a network interface involving taking a mutex which cannot be done in softirq context, so we need to defer this process to kthread context. This patch does the following: 1. introduce a flag to indicate the interface is disabled. 2. check that flag in TX path, don't do any work if it's true. 3. check that flag in RX path, turn off that interface if it's true. The reason to disable it in RX path is because RX uses kthread. After this change the behavior of netback is still consistent -- it won't do any TX work for a rogue frontend, and the interface will be eventually turned off. Also change a "continue" to "break" after xenvif_fatal_tx_err, as it doesn't make sense to continue processing packets if frontend is rogue. This is a fix for XSA-90. Reported-by: Török Edwin <edwin@etorok.net> Signed-off-by: Wei Liu <wei.liu2@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/xen-netback/netback.c')
1 files changed, 14 insertions, 2 deletions
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index ae34f5fc7fbc..3f021e054ba1 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -711,7 +711,8 @@ static void xenvif_tx_err(struct xenvif *vif,
static void xenvif_fatal_tx_err(struct xenvif *vif)
netdev_err(vif->dev, "fatal error; disabling device\n");
- xenvif_carrier_off(vif);
+ vif->disabled = true;
+ xenvif_kick_thread(vif);
static int xenvif_count_requests(struct xenvif *vif,
@@ -1212,7 +1213,7 @@ static unsigned xenvif_tx_build_gops(struct xenvif *vif, int budget)
vif->tx.sring->req_prod, vif->tx.req_cons,
- continue;
+ break;
work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&vif->tx);
@@ -1808,7 +1809,18 @@ int xenvif_kthread_guest_rx(void *data)
while (!kthread_should_stop()) {
rx_work_todo(vif) ||
+ vif->disabled ||
+ /* This frontend is found to be rogue, disable it in
+ * kthread context. Currently this is only set when
+ * netback finds out frontend sends malformed packet,
+ * but we cannot disable the interface in softirq
+ * context so we defer it here.
+ */
+ if (unlikely(vif->disabled && netif_carrier_ok(vif->dev)))
+ xenvif_carrier_off(vif);
if (kthread_should_stop())