Merge branch 'netback'
Ian Campbell says: ==================== The Xen netback implementation contains a couple of flaws which can allow a guest to cause a DoS in the backend domain, potentially affecting other domains in the system. CVE-2013-0216 is a failure to sanity check the ring producer/consumer pointers which can allow a guest to cause netback to loop for an extended period preventing other work from occurring. CVE-2013-0217 is a memory leak on an error path which is guest triggerable. The following series contains the fixes for these issues, as previously included in Xen Security Advisory 39: http://lists.xen.org/archives/html/xen-announce/2013-02/msg00001.html Changes in v2: - Typo and block comment format fixes - Added stable Cc ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller
Коммит
0c35565b46
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@ -151,6 +151,9 @@ 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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@ -343,17 +343,22 @@ err:
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return err;
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}
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void xenvif_disconnect(struct xenvif *vif)
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void xenvif_carrier_off(struct xenvif *vif)
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{
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struct net_device *dev = vif->dev;
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if (netif_carrier_ok(dev)) {
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rtnl_lock();
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netif_carrier_off(dev); /* discard queued packets */
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if (netif_running(dev))
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xenvif_down(vif);
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rtnl_unlock();
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xenvif_put(vif);
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}
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rtnl_lock();
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netif_carrier_off(dev); /* discard queued packets */
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if (netif_running(dev))
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xenvif_down(vif);
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rtnl_unlock();
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xenvif_put(vif);
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}
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void xenvif_disconnect(struct xenvif *vif)
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{
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if (netif_carrier_ok(vif->dev))
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xenvif_carrier_off(vif);
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atomic_dec(&vif->refcnt);
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wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0);
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@ -147,7 +147,8 @@ void xen_netbk_remove_xenvif(struct xenvif *vif)
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atomic_dec(&netbk->netfront_count);
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}
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static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx);
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static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx,
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u8 status);
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static void make_tx_response(struct xenvif *vif,
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struct xen_netif_tx_request *txp,
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s8 st);
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@ -879,7 +880,7 @@ static void netbk_tx_err(struct xenvif *vif,
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do {
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make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
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if (cons >= end)
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if (cons == end)
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break;
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txp = RING_GET_REQUEST(&vif->tx, cons++);
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} while (1);
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@ -888,6 +889,13 @@ static void netbk_tx_err(struct xenvif *vif,
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xenvif_put(vif);
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}
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static void netbk_fatal_tx_err(struct xenvif *vif)
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{
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netdev_err(vif->dev, "fatal error; disabling device\n");
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xenvif_carrier_off(vif);
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xenvif_put(vif);
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}
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static int netbk_count_requests(struct xenvif *vif,
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struct xen_netif_tx_request *first,
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struct xen_netif_tx_request *txp,
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@ -901,19 +909,22 @@ static int netbk_count_requests(struct xenvif *vif,
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do {
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if (frags >= work_to_do) {
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netdev_dbg(vif->dev, "Need more frags\n");
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netdev_err(vif->dev, "Need more frags\n");
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netbk_fatal_tx_err(vif);
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return -frags;
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}
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if (unlikely(frags >= MAX_SKB_FRAGS)) {
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netdev_dbg(vif->dev, "Too many frags\n");
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netdev_err(vif->dev, "Too many frags\n");
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netbk_fatal_tx_err(vif);
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return -frags;
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}
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memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + frags),
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sizeof(*txp));
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if (txp->size > first->size) {
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netdev_dbg(vif->dev, "Frags galore\n");
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netdev_err(vif->dev, "Frag is bigger than frame.\n");
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netbk_fatal_tx_err(vif);
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return -frags;
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}
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@ -921,8 +932,9 @@ static int netbk_count_requests(struct xenvif *vif,
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frags++;
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if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
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netdev_dbg(vif->dev, "txp->offset: %x, size: %u\n",
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netdev_err(vif->dev, "txp->offset: %x, size: %u\n",
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txp->offset, txp->size);
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netbk_fatal_tx_err(vif);
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return -frags;
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}
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} while ((txp++)->flags & XEN_NETTXF_more_data);
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@ -966,7 +978,7 @@ static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
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pending_idx = netbk->pending_ring[index];
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page = xen_netbk_alloc_page(netbk, skb, pending_idx);
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if (!page)
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return NULL;
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goto err;
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gop->source.u.ref = txp->gref;
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gop->source.domid = vif->domid;
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@ -988,6 +1000,17 @@ static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
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}
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return gop;
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err:
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/* Unwind, freeing all pages and sending error responses. */
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while (i-- > start) {
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xen_netbk_idx_release(netbk, frag_get_pending_idx(&frags[i]),
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XEN_NETIF_RSP_ERROR);
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}
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/* The head too, if necessary. */
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if (start)
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xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);
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return NULL;
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}
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static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
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@ -996,30 +1019,20 @@ static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
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{
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struct gnttab_copy *gop = *gopp;
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u16 pending_idx = *((u16 *)skb->data);
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struct pending_tx_info *pending_tx_info = netbk->pending_tx_info;
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struct xenvif *vif = pending_tx_info[pending_idx].vif;
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struct xen_netif_tx_request *txp;
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struct skb_shared_info *shinfo = skb_shinfo(skb);
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int nr_frags = shinfo->nr_frags;
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int i, err, start;
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/* Check status of header. */
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err = gop->status;
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if (unlikely(err)) {
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pending_ring_idx_t index;
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index = pending_index(netbk->pending_prod++);
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txp = &pending_tx_info[pending_idx].req;
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make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
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netbk->pending_ring[index] = pending_idx;
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xenvif_put(vif);
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}
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if (unlikely(err))
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xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);
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/* Skip first skb fragment if it is on same page as header fragment. */
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start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
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for (i = start; i < nr_frags; i++) {
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int j, newerr;
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pending_ring_idx_t index;
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pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
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@ -1028,16 +1041,12 @@ static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
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if (likely(!newerr)) {
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/* Had a previous error? Invalidate this fragment. */
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if (unlikely(err))
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xen_netbk_idx_release(netbk, pending_idx);
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xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
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continue;
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}
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/* Error on this fragment: respond to client with an error. */
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txp = &netbk->pending_tx_info[pending_idx].req;
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make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
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index = pending_index(netbk->pending_prod++);
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netbk->pending_ring[index] = pending_idx;
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xenvif_put(vif);
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xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);
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/* Not the first error? Preceding frags already invalidated. */
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if (err)
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@ -1045,10 +1054,10 @@ static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
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/* First error: invalidate header and preceding fragments. */
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pending_idx = *((u16 *)skb->data);
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xen_netbk_idx_release(netbk, pending_idx);
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xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
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for (j = start; j < i; j++) {
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pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
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xen_netbk_idx_release(netbk, pending_idx);
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xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
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}
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/* Remember the error: invalidate all subsequent fragments. */
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@ -1082,7 +1091,7 @@ static void xen_netbk_fill_frags(struct xen_netbk *netbk, struct sk_buff *skb)
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/* Take an extra reference to offset xen_netbk_idx_release */
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get_page(netbk->mmap_pages[pending_idx]);
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xen_netbk_idx_release(netbk, pending_idx);
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xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
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}
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}
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@ -1095,7 +1104,8 @@ static int xen_netbk_get_extras(struct xenvif *vif,
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do {
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if (unlikely(work_to_do-- <= 0)) {
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netdev_dbg(vif->dev, "Missing extra info\n");
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netdev_err(vif->dev, "Missing extra info\n");
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netbk_fatal_tx_err(vif);
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return -EBADR;
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}
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@ -1104,8 +1114,9 @@ static int xen_netbk_get_extras(struct xenvif *vif,
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if (unlikely(!extra.type ||
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extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
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vif->tx.req_cons = ++cons;
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netdev_dbg(vif->dev,
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netdev_err(vif->dev,
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"Invalid extra type: %d\n", extra.type);
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netbk_fatal_tx_err(vif);
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return -EINVAL;
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}
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@ -1121,13 +1132,15 @@ static int netbk_set_skb_gso(struct xenvif *vif,
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struct xen_netif_extra_info *gso)
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{
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if (!gso->u.gso.size) {
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netdev_dbg(vif->dev, "GSO size must not be zero.\n");
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netdev_err(vif->dev, "GSO size must not be zero.\n");
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netbk_fatal_tx_err(vif);
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return -EINVAL;
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}
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/* Currently only TCPv4 S.O. is supported. */
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if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
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netdev_dbg(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
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netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
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netbk_fatal_tx_err(vif);
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return -EINVAL;
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}
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@ -1264,9 +1277,25 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk)
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/* Get a netif from the list with work to do. */
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vif = poll_net_schedule_list(netbk);
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/* This can sometimes happen because the test of
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* list_empty(net_schedule_list) at the top of the
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* loop is unlocked. Just go back and have another
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* look.
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*/
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if (!vif)
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continue;
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if (vif->tx.sring->req_prod - vif->tx.req_cons >
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XEN_NETIF_TX_RING_SIZE) {
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netdev_err(vif->dev,
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"Impossible number of requests. "
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"req_prod %d, req_cons %d, size %ld\n",
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vif->tx.sring->req_prod, vif->tx.req_cons,
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XEN_NETIF_TX_RING_SIZE);
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netbk_fatal_tx_err(vif);
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continue;
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}
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RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, work_to_do);
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if (!work_to_do) {
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xenvif_put(vif);
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@ -1294,17 +1323,14 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk)
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work_to_do = xen_netbk_get_extras(vif, extras,
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work_to_do);
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idx = vif->tx.req_cons;
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if (unlikely(work_to_do < 0)) {
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netbk_tx_err(vif, &txreq, idx);
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if (unlikely(work_to_do < 0))
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continue;
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}
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}
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ret = netbk_count_requests(vif, &txreq, txfrags, work_to_do);
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if (unlikely(ret < 0)) {
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netbk_tx_err(vif, &txreq, idx - ret);
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if (unlikely(ret < 0))
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continue;
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}
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idx += ret;
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if (unlikely(txreq.size < ETH_HLEN)) {
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@ -1316,11 +1342,11 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk)
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/* No crossing a page as the payload mustn't fragment. */
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if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
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netdev_dbg(vif->dev,
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netdev_err(vif->dev,
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"txreq.offset: %x, size: %u, end: %lu\n",
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txreq.offset, txreq.size,
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(txreq.offset&~PAGE_MASK) + txreq.size);
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netbk_tx_err(vif, &txreq, idx);
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netbk_fatal_tx_err(vif);
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continue;
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}
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@ -1348,8 +1374,8 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk)
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gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
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if (netbk_set_skb_gso(vif, skb, gso)) {
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/* Failure in netbk_set_skb_gso is fatal. */
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kfree_skb(skb);
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netbk_tx_err(vif, &txreq, idx);
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continue;
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}
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}
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@ -1448,7 +1474,7 @@ static void xen_netbk_tx_submit(struct xen_netbk *netbk)
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txp->size -= data_len;
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} else {
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/* Schedule a response immediately. */
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xen_netbk_idx_release(netbk, pending_idx);
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xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
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}
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if (txp->flags & XEN_NETTXF_csum_blank)
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@ -1500,7 +1526,8 @@ static void xen_netbk_tx_action(struct xen_netbk *netbk)
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xen_netbk_tx_submit(netbk);
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}
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static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx)
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static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx,
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u8 status)
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{
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struct xenvif *vif;
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struct pending_tx_info *pending_tx_info;
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@ -1514,7 +1541,7 @@ static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx)
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vif = pending_tx_info->vif;
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make_tx_response(vif, &pending_tx_info->req, XEN_NETIF_RSP_OKAY);
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make_tx_response(vif, &pending_tx_info->req, status);
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index = pending_index(netbk->pending_prod++);
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netbk->pending_ring[index] = pending_idx;
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|
|
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