--- /dev/null
+From b284e80e04b7181353963ed98a6ae5b0eb24672f Mon Sep 17 00:00:00 2001
+From: Matthew Daley <mattjd@gmail.com>
+Date: Wed, 6 Feb 2013 23:41:36 +0000
+Subject: xen/netback: don't leak pages on failure in xen_netbk_tx_check_gop.
+
+
+From: Matthew Daley <mattjd@gmail.com>
+
+[ Upstream commit 7d5145d8eb2b9791533ffe4dc003b129b9696c48 ]
+
+Signed-off-by: Matthew Daley <mattjd@gmail.com>
+Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Acked-by: Ian Campbell <ian.campbell@citrix.com>
+Acked-by: Jan Beulich <JBeulich@suse.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/net/xen-netback/netback.c | 40 +++++++++++++-------------------------
+ 1 file changed, 14 insertions(+), 26 deletions(-)
+
+--- a/drivers/net/xen-netback/netback.c
++++ b/drivers/net/xen-netback/netback.c
+@@ -143,7 +143,8 @@ void xen_netbk_remove_xenvif(struct xenv
+ atomic_dec(&netbk->netfront_count);
+ }
+
+-static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx);
++static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx,
++ u8 status);
+ static void make_tx_response(struct xenvif *vif,
+ struct xen_netif_tx_request *txp,
+ s8 st);
+@@ -968,30 +969,20 @@ static int xen_netbk_tx_check_gop(struct
+ {
+ struct gnttab_copy *gop = *gopp;
+ int pending_idx = *((u16 *)skb->data);
+- struct pending_tx_info *pending_tx_info = netbk->pending_tx_info;
+- struct xenvif *vif = pending_tx_info[pending_idx].vif;
+- struct xen_netif_tx_request *txp;
+ struct skb_shared_info *shinfo = skb_shinfo(skb);
+ int nr_frags = shinfo->nr_frags;
+ int i, err, start;
+
+ /* Check status of header. */
+ err = gop->status;
+- if (unlikely(err)) {
+- pending_ring_idx_t index;
+- index = pending_index(netbk->pending_prod++);
+- txp = &pending_tx_info[pending_idx].req;
+- make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
+- netbk->pending_ring[index] = pending_idx;
+- xenvif_put(vif);
+- }
++ if (unlikely(err))
++ xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);
+
+ /* Skip first skb fragment if it is on same page as header fragment. */
+- start = ((unsigned long)shinfo->frags[0].page == pending_idx);
++ start = ((unsigned long)shinfo->frags[i].page == pending_idx);
+
+ for (i = start; i < nr_frags; i++) {
+ int j, newerr;
+- pending_ring_idx_t index;
+
+ pending_idx = (unsigned long)shinfo->frags[i].page;
+
+@@ -1000,16 +991,12 @@ static int xen_netbk_tx_check_gop(struct
+ if (likely(!newerr)) {
+ /* Had a previous error? Invalidate this fragment. */
+ if (unlikely(err))
+- xen_netbk_idx_release(netbk, pending_idx);
++ xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
+ continue;
+ }
+
+ /* Error on this fragment: respond to client with an error. */
+- txp = &netbk->pending_tx_info[pending_idx].req;
+- make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
+- index = pending_index(netbk->pending_prod++);
+- netbk->pending_ring[index] = pending_idx;
+- xenvif_put(vif);
++ xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);
+
+ /* Not the first error? Preceding frags already invalidated. */
+ if (err)
+@@ -1017,10 +1004,10 @@ static int xen_netbk_tx_check_gop(struct
+
+ /* First error: invalidate header and preceding fragments. */
+ pending_idx = *((u16 *)skb->data);
+- xen_netbk_idx_release(netbk, pending_idx);
++ xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
+ for (j = start; j < i; j++) {
+ pending_idx = (unsigned long)shinfo->frags[i].page;
+- xen_netbk_idx_release(netbk, pending_idx);
++ xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
+ }
+
+ /* Remember the error: invalidate all subsequent fragments. */
+@@ -1055,7 +1042,7 @@ static void xen_netbk_fill_frags(struct
+
+ /* Take an extra reference to offset xen_netbk_idx_release */
+ get_page(netbk->mmap_pages[pending_idx]);
+- xen_netbk_idx_release(netbk, pending_idx);
++ xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
+ }
+ }
+
+@@ -1440,7 +1427,7 @@ static void xen_netbk_tx_submit(struct x
+ txp->size -= data_len;
+ } else {
+ /* Schedule a response immediately. */
+- xen_netbk_idx_release(netbk, pending_idx);
++ xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
+ }
+
+ if (txp->flags & XEN_NETTXF_csum_blank)
+@@ -1495,7 +1482,8 @@ static void xen_netbk_tx_action(struct x
+
+ }
+
+-static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx)
++static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx,
++ u8 status)
+ {
+ struct xenvif *vif;
+ struct pending_tx_info *pending_tx_info;
+@@ -1509,7 +1497,7 @@ static void xen_netbk_idx_release(struct
+
+ vif = pending_tx_info->vif;
+
+- make_tx_response(vif, &pending_tx_info->req, XEN_NETIF_RSP_OKAY);
++ make_tx_response(vif, &pending_tx_info->req, status);
+
+ index = pending_index(netbk->pending_prod++);
+ netbk->pending_ring[index] = pending_idx;
--- /dev/null
+From cd670b23c148db94a7f8e3d2424aa2f51f5aac21 Mon Sep 17 00:00:00 2001
+From: Ian Campbell <Ian.Campbell@citrix.com>
+Date: Wed, 6 Feb 2013 23:41:35 +0000
+Subject: xen/netback: shutdown the ring if it contains garbage.
+
+
+From: Ian Campbell <Ian.Campbell@citrix.com>
+
+[ Upstream commit 48856286b64e4b66ec62b94e504d0b29c1ade664 ]
+
+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>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ 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(-)
+
+--- a/drivers/net/xen-netback/common.h
++++ b/drivers/net/xen-netback/common.h
+@@ -152,6 +152,9 @@ void xen_netbk_queue_tx_skb(struct xenvi
+ /* 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);
+
+--- a/drivers/net/xen-netback/interface.c
++++ b/drivers/net/xen-netback/interface.c
+@@ -342,17 +342,22 @@ 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);
+--- a/drivers/net/xen-netback/netback.c
++++ b/drivers/net/xen-netback/netback.c
+@@ -847,6 +847,13 @@ static void netbk_tx_err(struct xenvif *
+ 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,
+@@ -860,19 +867,22 @@ static int netbk_count_requests(struct x
+
+ 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;
+ }
+
+@@ -880,8 +890,9 @@ static int netbk_count_requests(struct x
+ 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);
+@@ -1057,7 +1068,8 @@ static int xen_netbk_get_extras(struct x
+
+ 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;
+ }
+
+@@ -1066,8 +1078,9 @@ static int xen_netbk_get_extras(struct x
+ 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;
+ }
+
+@@ -1083,13 +1096,15 @@ static int netbk_set_skb_gso(struct xenv
+ 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;
+ }
+
+@@ -1226,9 +1241,25 @@ static unsigned xen_netbk_tx_build_gops(
+
+ /* 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);
+@@ -1256,17 +1287,14 @@ static unsigned xen_netbk_tx_build_gops(
+ 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)) {
+@@ -1278,11 +1306,11 @@ static unsigned xen_netbk_tx_build_gops(
+
+ /* 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;
+ }
+
+@@ -1310,8 +1338,8 @@ static unsigned xen_netbk_tx_build_gops(
+ 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;
+ }
+ }
projects / thirdparty / kernel / stable-queue.git / commitdiff
