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authorDavid S. Miller <davem@davemloft.net>2013-02-07 23:31:47 -0500
committerDavid S. Miller <davem@davemloft.net>2013-02-07 23:31:47 -0500
commit0c35565b460ff99f973fb4a9ec63fbcb4176d2e6 (patch)
treef0293db254c3db8dfee6c624bba307e3308162f7 /drivers
parente21b9d031fa184632c373eedc12e3c296e1aa65b (diff)
parentb9149729ebdcfce63f853aa54a404c6a8f6ebbf3 (diff)
downloadlinaro-lsk-0c35565b460ff99f973fb4a9ec63fbcb4176d2e6.tar.gz
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/xen-netback/common.h3
-rw-r--r--drivers/net/xen-netback/interface.c23
-rw-r--r--drivers/net/xen-netback/netback.c115
3 files changed, 88 insertions, 53 deletions
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..2b9520c46e9 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -147,7 +147,8 @@ void xen_netbk_remove_xenvif(struct xenvif *vif)
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);
@@ -879,7 +880,7 @@ static void netbk_tx_err(struct xenvif *vif,
do {
make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
- if (cons >= end)
+ if (cons == end)
break;
txp = RING_GET_REQUEST(&vif->tx, cons++);
} while (1);
@@ -888,6 +889,13 @@ 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 +909,22 @@ 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 +932,9 @@ 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);
@@ -966,7 +978,7 @@ static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
pending_idx = netbk->pending_ring[index];
page = xen_netbk_alloc_page(netbk, skb, pending_idx);
if (!page)
- return NULL;
+ goto err;
gop->source.u.ref = txp->gref;
gop->source.domid = vif->domid;
@@ -988,6 +1000,17 @@ static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
}
return gop;
+err:
+ /* Unwind, freeing all pages and sending error responses. */
+ while (i-- > start) {
+ xen_netbk_idx_release(netbk, frag_get_pending_idx(&frags[i]),
+ XEN_NETIF_RSP_ERROR);
+ }
+ /* The head too, if necessary. */
+ if (start)
+ xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);
+
+ return NULL;
}
static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
@@ -996,30 +1019,20 @@ static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
{
struct gnttab_copy *gop = *gopp;
u16 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 = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
for (i = start; i < nr_frags; i++) {
int j, newerr;
- pending_ring_idx_t index;
pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
@@ -1028,16 +1041,12 @@ static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
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)
@@ -1045,10 +1054,10 @@ static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
/* 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 = frag_get_pending_idx(&shinfo->frags[j]);
- 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. */
@@ -1082,7 +1091,7 @@ static void xen_netbk_fill_frags(struct xen_netbk *netbk, struct sk_buff *skb)
/* 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);
}
}
@@ -1095,7 +1104,8 @@ 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 +1114,9 @@ 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 +1132,15 @@ 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 +1277,25 @@ 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 +1323,14 @@ 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 +1342,11 @@ 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 +1374,8 @@ 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;
}
}
@@ -1448,7 +1474,7 @@ static void xen_netbk_tx_submit(struct xen_netbk *netbk)
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)
@@ -1500,7 +1526,8 @@ static void xen_netbk_tx_action(struct xen_netbk *netbk)
xen_netbk_tx_submit(netbk);
}
-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;
@@ -1514,7 +1541,7 @@ static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx)
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;