1 files changed, 46 insertions, 0 deletions
diff --git a/main/xen/xsa135-qemut-2.patch b/main/xen/xsa135-qemut-2.patch
new file mode 100644
index 0000000000..2b0631af7c
--- /dev/null
+++ b/main/xen/xsa135-qemut-2.patch
@@ -0,0 +1,46 @@
+From 2630672ab22255de252f877709851c0557a1c647 Mon Sep 17 00:00:00 2001
+From: Petr Matousek <pmatouse@redhat.com>
+Date: Sun, 24 May 2015 10:53:44 +0200
+Subject: [PATCH] pcnet: force the buffer access to be in bounds during tx
+
+4096 is the maximum length per TMD and it is also currently the size of
+the relay buffer pcnet driver uses for sending the packet data to QEMU
+for further processing. With packet spanning multiple TMDs it can
+happen that the overall packet size will be bigger than sizeof(buffer),
+which results in memory corruption.
+
+Fix this by only allowing to queue maximum sizeof(buffer) bytes.
+
+This is CVE-2015-3209.
+
+Signed-off-by: Petr Matousek <pmatouse@redhat.com>
+Reported-by: Matt Tait <matttait@google.com>
+Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
+Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
+---
+ hw/pcnet.c | 8 ++++++++
+ 1 file changed, 8 insertions(+)
+
+diff --git a/hw/pcnet.c b/hw/pcnet.c
+index bdfd38f..6d32e4c 100644
+--- a/tools/qemu-xen-traditional/hw/pcnet.c
++++ b/tools/qemu-xen-traditional/hw/pcnet.c
+@@ -1241,6 +1241,14 @@ static void pcnet_transmit(PCNetState *s)
+         }
+
+         bcnt = 4096 - GET_FIELD(tmd.length, TMDL, BCNT);
++
++        /* if multi-tmd packet outsizes s->buffer then skip it silently.
++           Note: this is not what real hw does */
++        if (s->xmit_pos + bcnt > sizeof(s->buffer)) {
++           s->xmit_pos = -1;
++           goto txdone;
++        }
++
+         s->phys_mem_read(s->dma_opaque, PHYSADDR(s, tmd.tbadr),
+                          s->buffer + s->xmit_pos, bcnt, CSR_BSWP(s));
+         s->xmit_pos += bcnt;
+-- 
+2.1.0
+
+