48856286b6
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 <ian.campbell@citrix.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Jan Beulich <JBeulich@suse.com> Signed-off-by: David S. Miller <davem@davemloft.net>
161 lines
5.2 KiB
C
161 lines
5.2 KiB
C
/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation; or, when distributed
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* separately from the Linux kernel or incorporated into other
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* software packages, subject to the following license:
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this source file (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy, modify,
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* merge, publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#ifndef __XEN_NETBACK__COMMON_H__
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#define __XEN_NETBACK__COMMON_H__
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#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/slab.h>
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#include <linux/ip.h>
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#include <linux/in.h>
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#include <linux/io.h>
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/wait.h>
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#include <linux/sched.h>
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#include <xen/interface/io/netif.h>
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#include <xen/interface/grant_table.h>
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#include <xen/grant_table.h>
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#include <xen/xenbus.h>
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struct xen_netbk;
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struct xenvif {
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/* Unique identifier for this interface. */
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domid_t domid;
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unsigned int handle;
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/* Reference to netback processing backend. */
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struct xen_netbk *netbk;
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u8 fe_dev_addr[6];
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/* Physical parameters of the comms window. */
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unsigned int irq;
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/* List of frontends to notify after a batch of frames sent. */
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struct list_head notify_list;
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/* The shared rings and indexes. */
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struct xen_netif_tx_back_ring tx;
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struct xen_netif_rx_back_ring rx;
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/* Frontend feature information. */
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u8 can_sg:1;
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u8 gso:1;
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u8 gso_prefix:1;
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u8 csum:1;
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/* Internal feature information. */
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u8 can_queue:1; /* can queue packets for receiver? */
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/*
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* Allow xenvif_start_xmit() to peek ahead in the rx request
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* ring. This is a prediction of what rx_req_cons will be
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* once all queued skbs are put on the ring.
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*/
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RING_IDX rx_req_cons_peek;
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/* Transmit shaping: allow 'credit_bytes' every 'credit_usec'. */
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unsigned long credit_bytes;
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unsigned long credit_usec;
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unsigned long remaining_credit;
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struct timer_list credit_timeout;
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/* Statistics */
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unsigned long rx_gso_checksum_fixup;
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/* Miscellaneous private stuff. */
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struct list_head schedule_list;
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atomic_t refcnt;
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struct net_device *dev;
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wait_queue_head_t waiting_to_free;
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};
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static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
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{
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return to_xenbus_device(vif->dev->dev.parent);
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}
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#define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
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#define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
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struct xenvif *xenvif_alloc(struct device *parent,
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domid_t domid,
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unsigned int handle);
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int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
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unsigned long rx_ring_ref, unsigned int evtchn);
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void xenvif_disconnect(struct xenvif *vif);
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void xenvif_get(struct xenvif *vif);
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void xenvif_put(struct xenvif *vif);
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int xenvif_xenbus_init(void);
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int xenvif_schedulable(struct xenvif *vif);
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int xen_netbk_rx_ring_full(struct xenvif *vif);
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int xen_netbk_must_stop_queue(struct xenvif *vif);
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/* (Un)Map communication rings. */
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void xen_netbk_unmap_frontend_rings(struct xenvif *vif);
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int xen_netbk_map_frontend_rings(struct xenvif *vif,
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grant_ref_t tx_ring_ref,
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grant_ref_t rx_ring_ref);
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/* (De)Register a xenvif with the netback backend. */
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void xen_netbk_add_xenvif(struct xenvif *vif);
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void xen_netbk_remove_xenvif(struct xenvif *vif);
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/* (De)Schedule backend processing for a xenvif */
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void xen_netbk_schedule_xenvif(struct xenvif *vif);
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void xen_netbk_deschedule_xenvif(struct xenvif *vif);
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/* Check for SKBs from frontend and schedule backend processing */
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void xen_netbk_check_rx_xenvif(struct xenvif *vif);
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/* Receive an SKB from the frontend */
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void xenvif_receive_skb(struct xenvif *vif, struct sk_buff *skb);
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/* Queue an SKB for transmission to the frontend */
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void xen_netbk_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb);
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/* Notify xenvif that ring now has space to send an skb to the frontend */
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void xenvif_notify_tx_completion(struct xenvif *vif);
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/* Prevent the device from generating any further traffic. */
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void xenvif_carrier_off(struct xenvif *vif);
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/* Returns number of ring slots required to send an skb to the frontend */
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unsigned int xen_netbk_count_skb_slots(struct xenvif *vif, struct sk_buff *skb);
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#endif /* __XEN_NETBACK__COMMON_H__ */
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