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From a3f3310a41ed5af1c701fea5dd7892dd9409e7d8 Mon Sep 17 00:00:00 2001
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From: Michael S. Tsirkin <mst@redhat.com>
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Date: Wed, 14 May 2014 08:07:42 +0200
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Subject: [PATCH 02/30] virtio-net: out-of-bounds buffer write on load
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RH-Author: Michael S. Tsirkin <mst@redhat.com>
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Message-id: <1400054498-4366-2-git-send-email-mst@redhat.com>
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Patchwork-id: 58840
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O-Subject: [PATCH qemu-kvm RHEL7.0] virtio-net: out-of-bounds buffer write on load
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Bugzilla: 1095684
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RH-Acked-by: Dr. David Alan Gilbert (git) <dgilbert@redhat.com>
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RH-Acked-by: Xiao Wang <jasowang@redhat.com>
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RH-Acked-by: Juan Quintela <quintela@redhat.com>
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CVE-2013-4149 QEMU 1.3.0 out-of-bounds buffer write in
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virtio_net_load()@hw/net/virtio-net.c
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> } else if (n->mac_table.in_use) {
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> uint8_t *buf = g_malloc0(n->mac_table.in_use);
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We are allocating buffer of size n->mac_table.in_use
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> qemu_get_buffer(f, buf, n->mac_table.in_use * ETH_ALEN);
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and read to the n->mac_table.in_use size buffer n->mac_table.in_use *
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ETH_ALEN bytes, corrupting memory.
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If adversary controls state then memory written there is controlled
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by adversary.
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Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
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Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Signed-off-by: Juan Quintela <quintela@redhat.com>
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(cherry picked from commit 98f93ddd84800f207889491e0b5d851386b459cf)
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Bugzilla: 1095684
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Tested: lightly on developer's box
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Brew build: http://brewweb.devel.redhat.com/brew/taskinfo?taskID=7450401
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---
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hw/net/virtio-net.c | 15 +++++++++++----
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1 file changed, 11 insertions(+), 4 deletions(-)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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hw/net/virtio-net.c | 15 +++++++++++----
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1 files changed, 11 insertions(+), 4 deletions(-)
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diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
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index 2d559e0..f6ed241 100644
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--- a/hw/net/virtio-net.c
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+++ b/hw/net/virtio-net.c
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@@ -1273,10 +1273,17 @@ static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)
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if (n->mac_table.in_use <= MAC_TABLE_ENTRIES) {
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qemu_get_buffer(f, n->mac_table.macs,
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n->mac_table.in_use * ETH_ALEN);
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- } else if (n->mac_table.in_use) {
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- uint8_t *buf = g_malloc0(n->mac_table.in_use);
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- qemu_get_buffer(f, buf, n->mac_table.in_use * ETH_ALEN);
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- g_free(buf);
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+ } else {
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+ int64_t i;
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+
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+ /* Overflow detected - can happen if source has a larger MAC table.
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+ * We simply set overflow flag so there's no need to maintain the
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+ * table of addresses, discard them all.
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+ * Note: 64 bit math to avoid integer overflow.
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+ */
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+ for (i = 0; i < (int64_t)n->mac_table.in_use * ETH_ALEN; ++i) {
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+ qemu_get_byte(f);
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+ }
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n->mac_table.multi_overflow = n->mac_table.uni_overflow = 1;
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n->mac_table.in_use = 0;
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}
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--
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1.7.1
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