From 4a633a602c26497b8285a202830829d3be007c7b Mon Sep 17 00:00:00 2001 From: Matt Wilson Date: Tue, 22 Jan 2013 08:08:25 +0000 Subject: xen-netback: allow changing the MAC address of the interface Sometimes it is useful to be able to change the MAC address of the interface for netback devices. For example, when using ebtables it may be useful to be able to distinguish traffic from different interfaces without depending on the interface name. Reported-by: Nikita Borzykh Reported-by: Paul Harvey Cc: netdev@vger.kernel.org Cc: xen-devel@lists.xen.org Cc: Konrad Rzeszutek Wilk Acked-by: Ian Campbell Signed-off-by: Matt Wilson Reviewed-by: Konrad Rzeszutek Wilk Signed-off-by: David S. Miller --- drivers/net/xen-netback/interface.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/net/xen-netback/interface.c') diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index b7d41f8c338..f733cae3d4b 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -238,6 +238,8 @@ static const struct net_device_ops xenvif_netdev_ops = { .ndo_stop = xenvif_close, .ndo_change_mtu = xenvif_change_mtu, .ndo_fix_features = xenvif_fix_features, + .ndo_set_mac_address = eth_mac_addr, + .ndo_validate_addr = eth_validate_addr, }; struct xenvif *xenvif_alloc(struct device *parent, domid_t domid, -- cgit v1.2.3-70-g09d2 From 48856286b64e4b66ec62b94e504d0b29c1ade664 Mon Sep 17 00:00:00 2001 From: Ian Campbell Date: Wed, 6 Feb 2013 23:41:35 +0000 Subject: xen/netback: shutdown the ring if it contains garbage. A buggy or malicious frontend should not be able to confuse netback. If we spot anything which is not as it should be then shutdown the device and don't try to continue with the ring in a potentially hostile state. Well behaved and non-hostile frontends will not be penalised. As well as making the existing checks for such errors fatal also add a new check that ensures that there isn't an insane number of requests on the ring (i.e. more than would fit in the ring). If the ring contains garbage then previously is was possible to loop over this insane number, getting an error each time and therefore not generating any more pending requests and therefore not exiting the loop in xen_netbk_tx_build_gops for an externded period. Also turn various netdev_dbg calls which no precipitate a fatal error into netdev_err, they are rate limited because the device is shutdown afterwards. This fixes at least one known DoS/softlockup of the backend domain. Signed-off-by: Ian Campbell Reviewed-by: Konrad Rzeszutek Wilk Acked-by: Jan Beulich Signed-off-by: David S. Miller --- drivers/net/xen-netback/common.h | 3 ++ drivers/net/xen-netback/interface.c | 23 ++++++++------ drivers/net/xen-netback/netback.c | 62 +++++++++++++++++++++++++++---------- 3 files changed, 62 insertions(+), 26 deletions(-) (limited to 'drivers/net/xen-netback/interface.c') diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h index 94b79c3338c..9d7f1723dd8 100644 --- a/drivers/net/xen-netback/common.h +++ b/drivers/net/xen-netback/common.h @@ -151,6 +151,9 @@ void xen_netbk_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb); /* Notify xenvif that ring now has space to send an skb to the frontend */ void xenvif_notify_tx_completion(struct xenvif *vif); +/* Prevent the device from generating any further traffic. */ +void xenvif_carrier_off(struct xenvif *vif); + /* Returns number of ring slots required to send an skb to the frontend */ unsigned int xen_netbk_count_skb_slots(struct xenvif *vif, struct sk_buff *skb); diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index b7d41f8c338..b8c5193bd42 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -343,17 +343,22 @@ err: return err; } -void xenvif_disconnect(struct xenvif *vif) +void xenvif_carrier_off(struct xenvif *vif) { struct net_device *dev = vif->dev; - if (netif_carrier_ok(dev)) { - rtnl_lock(); - netif_carrier_off(dev); /* discard queued packets */ - if (netif_running(dev)) - xenvif_down(vif); - rtnl_unlock(); - xenvif_put(vif); - } + + rtnl_lock(); + netif_carrier_off(dev); /* discard queued packets */ + if (netif_running(dev)) + xenvif_down(vif); + rtnl_unlock(); + xenvif_put(vif); +} + +void xenvif_disconnect(struct xenvif *vif) +{ + if (netif_carrier_ok(vif->dev)) + xenvif_carrier_off(vif); atomic_dec(&vif->refcnt); wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0); diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index f2d6b78d901..c2e3336b4f9 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -888,6 +888,13 @@ static void netbk_tx_err(struct xenvif *vif, xenvif_put(vif); } +static void netbk_fatal_tx_err(struct xenvif *vif) +{ + netdev_err(vif->dev, "fatal error; disabling device\n"); + xenvif_carrier_off(vif); + xenvif_put(vif); +} + static int netbk_count_requests(struct xenvif *vif, struct xen_netif_tx_request *first, struct xen_netif_tx_request *txp, @@ -901,19 +908,22 @@ static int netbk_count_requests(struct xenvif *vif, do { if (frags >= work_to_do) { - netdev_dbg(vif->dev, "Need more frags\n"); + netdev_err(vif->dev, "Need more frags\n"); + netbk_fatal_tx_err(vif); return -frags; } if (unlikely(frags >= MAX_SKB_FRAGS)) { - netdev_dbg(vif->dev, "Too many frags\n"); + netdev_err(vif->dev, "Too many frags\n"); + netbk_fatal_tx_err(vif); return -frags; } memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + frags), sizeof(*txp)); if (txp->size > first->size) { - netdev_dbg(vif->dev, "Frags galore\n"); + netdev_err(vif->dev, "Frag is bigger than frame.\n"); + netbk_fatal_tx_err(vif); return -frags; } @@ -921,8 +931,9 @@ static int netbk_count_requests(struct xenvif *vif, frags++; if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) { - netdev_dbg(vif->dev, "txp->offset: %x, size: %u\n", + netdev_err(vif->dev, "txp->offset: %x, size: %u\n", txp->offset, txp->size); + netbk_fatal_tx_err(vif); return -frags; } } while ((txp++)->flags & XEN_NETTXF_more_data); @@ -1095,7 +1106,8 @@ static int xen_netbk_get_extras(struct xenvif *vif, do { if (unlikely(work_to_do-- <= 0)) { - netdev_dbg(vif->dev, "Missing extra info\n"); + netdev_err(vif->dev, "Missing extra info\n"); + netbk_fatal_tx_err(vif); return -EBADR; } @@ -1104,8 +1116,9 @@ static int xen_netbk_get_extras(struct xenvif *vif, if (unlikely(!extra.type || extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) { vif->tx.req_cons = ++cons; - netdev_dbg(vif->dev, + netdev_err(vif->dev, "Invalid extra type: %d\n", extra.type); + netbk_fatal_tx_err(vif); return -EINVAL; } @@ -1121,13 +1134,15 @@ static int netbk_set_skb_gso(struct xenvif *vif, struct xen_netif_extra_info *gso) { if (!gso->u.gso.size) { - netdev_dbg(vif->dev, "GSO size must not be zero.\n"); + netdev_err(vif->dev, "GSO size must not be zero.\n"); + netbk_fatal_tx_err(vif); return -EINVAL; } /* Currently only TCPv4 S.O. is supported. */ if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) { - netdev_dbg(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type); + netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type); + netbk_fatal_tx_err(vif); return -EINVAL; } @@ -1264,9 +1279,25 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk) /* Get a netif from the list with work to do. */ vif = poll_net_schedule_list(netbk); + /* This can sometimes happen because the test of + * list_empty(net_schedule_list) at the top of the + * loop is unlocked. Just go back and have another + * look. + */ if (!vif) continue; + if (vif->tx.sring->req_prod - vif->tx.req_cons > + XEN_NETIF_TX_RING_SIZE) { + netdev_err(vif->dev, + "Impossible number of requests. " + "req_prod %d, req_cons %d, size %ld\n", + vif->tx.sring->req_prod, vif->tx.req_cons, + XEN_NETIF_TX_RING_SIZE); + netbk_fatal_tx_err(vif); + continue; + } + RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, work_to_do); if (!work_to_do) { xenvif_put(vif); @@ -1294,17 +1325,14 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk) work_to_do = xen_netbk_get_extras(vif, extras, work_to_do); idx = vif->tx.req_cons; - if (unlikely(work_to_do < 0)) { - netbk_tx_err(vif, &txreq, idx); + if (unlikely(work_to_do < 0)) continue; - } } ret = netbk_count_requests(vif, &txreq, txfrags, work_to_do); - if (unlikely(ret < 0)) { - netbk_tx_err(vif, &txreq, idx - ret); + if (unlikely(ret < 0)) continue; - } + idx += ret; if (unlikely(txreq.size < ETH_HLEN)) { @@ -1316,11 +1344,11 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk) /* No crossing a page as the payload mustn't fragment. */ if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) { - netdev_dbg(vif->dev, + netdev_err(vif->dev, "txreq.offset: %x, size: %u, end: %lu\n", txreq.offset, txreq.size, (txreq.offset&~PAGE_MASK) + txreq.size); - netbk_tx_err(vif, &txreq, idx); + netbk_fatal_tx_err(vif); continue; } @@ -1348,8 +1376,8 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk) gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1]; if (netbk_set_skb_gso(vif, skb, gso)) { + /* Failure in netbk_set_skb_gso is fatal. */ kfree_skb(skb); - netbk_tx_err(vif, &txreq, idx); continue; } } -- cgit v1.2.3-70-g09d2 From 3e55f8b306cf305832a4ac78aa82e1b40e818ece Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Thu, 14 Feb 2013 03:18:58 +0000 Subject: xen-netback: cancel the credit timer when taking the vif down If the credit timer is left armed after calling xen_netbk_remove_xenvif(), then it may fire and attempt to schedule the vif which will then oops as vif->netbk == NULL. This may happen both in the fatal error path and during normal disconnection from the front end. The sequencing during shutdown is critical to ensure that: a) vif->netbk doesn't become unexpectedly NULL; and b) the net device/vif is not freed. 1. Mark as unschedulable (netif_carrier_off()). 2. Synchronously cancel the timer. 3. Remove the vif from the schedule list. 4. Remove it from it netback thread group. 5. Wait for vif->refcnt to become 0. Signed-off-by: David Vrabel Acked-by: Ian Campbell Reported-by: Christopher S. Aker Signed-off-by: David S. Miller --- drivers/net/xen-netback/interface.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'drivers/net/xen-netback/interface.c') diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index b8c5193bd42..221f4265f7d 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -132,6 +132,7 @@ static void xenvif_up(struct xenvif *vif) static void xenvif_down(struct xenvif *vif) { disable_irq(vif->irq); + del_timer_sync(&vif->credit_timeout); xen_netbk_deschedule_xenvif(vif); xen_netbk_remove_xenvif(vif); } @@ -363,8 +364,6 @@ void xenvif_disconnect(struct xenvif *vif) atomic_dec(&vif->refcnt); wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0); - del_timer_sync(&vif->credit_timeout); - if (vif->irq) unbind_from_irqhandler(vif->irq, vif); -- cgit v1.2.3-70-g09d2