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From ea96c6a9c91da1923aa922a781fd7abbf9f51b6c Mon Sep 17 00:00:00 2001
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From: "Michael S. Tsirkin" <mst@redhat.com>
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Date: Thu, 3 Apr 2014 19:50:39 +0300
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Subject: [PATCH] virtio-net: fix buffer overflow on invalid state load
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CVE-2013-4148 QEMU 1.0 integer conversion in
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virtio_net_load()@hw/net/virtio-net.c
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Deals with loading a corrupted savevm image.
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> n->mac_table.in_use = qemu_get_be32(f);
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in_use is int so it can get negative when assigned 32bit unsigned value.
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> /* MAC_TABLE_ENTRIES may be different from the saved image */
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> if (n->mac_table.in_use <= MAC_TABLE_ENTRIES) {
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passing this check ^^^
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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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with good in_use value, "n->mac_table.in_use * ETH_ALEN" can get
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positive and bigger than mac_table.macs. For example 0x81000000
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satisfies this condition when ETH_ALEN is 6.
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Fix it by making the value unsigned.
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For consistency, change first_multi as well.
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Note: all call sites were audited to confirm that
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making them unsigned didn't cause any issues:
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it turns out we actually never do math on them,
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so it's easy to validate because both values are
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always <= MAC_TABLE_ENTRIES.
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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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Reviewed-by: Laszlo Ersek <lersek@redhat.com>
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Signed-off-by: Juan Quintela <quintela@redhat.com>
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(cherry picked from commit 71f7fe48e10a8437c9d42d859389f37157f59980)
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---
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include/hw/virtio/virtio-net.h | 4 ++--
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1 file changed, 2 insertions(+), 2 deletions(-)
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diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h
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index df60f16..4b32440 100644
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--- a/include/hw/virtio/virtio-net.h
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+++ b/include/hw/virtio/virtio-net.h
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@@ -176,8 +176,8 @@ typedef struct VirtIONet {
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uint8_t nobcast;
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uint8_t vhost_started;
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struct {
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- int in_use;
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- int first_multi;
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+ uint32_t in_use;
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+ uint32_t first_multi;
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uint8_t multi_overflow;
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uint8_t uni_overflow;
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uint8_t *macs;
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