Blame SOURCES/kvm-virtio-validate-num_sg-when-mapping.patch

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From 24625e2c2eb6e259b621c7ff11671977fa705578 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 08:11:56 +0200
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Subject: [PATCH 08/30] virtio: validate num_sg when mapping
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RH-Author: Michael S. Tsirkin <mst@redhat.com>
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Message-id: <1400054952-6106-1-git-send-email-mst@redhat.com>
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Patchwork-id: 58846
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O-Subject: [PATCH qemu-kvm RHEL7.0 1/2] virtio: validate num_sg when mapping
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Bugzilla: 1095765
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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: Amos Kong <akong@redhat.com>
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CVE-2013-4535
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CVE-2013-4536
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Both virtio-block and virtio-serial read,
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VirtQueueElements are read in as buffers, and passed to
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virtqueue_map_sg(), where num_sg is taken from the wire and can force
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writes to indicies beyond VIRTQUEUE_MAX_SIZE.
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To fix, validate num_sg.
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Reported-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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Cc: Amit Shah <amit.shah@redhat.com>
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Signed-off-by: Juan Quintela <quintela@redhat.com>
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(cherry picked from commit 36cf2a37132c7f01fa9adb5f95f5312b27742fd4)
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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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Bugzilla:1095765
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---
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 hw/virtio/virtio.c | 6 ++++++
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 1 file changed, 6 insertions(+)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 hw/virtio/virtio.c |    6 ++++++
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 1 files changed, 6 insertions(+), 0 deletions(-)
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diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
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index 686dfbb..2667390 100644
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--- a/hw/virtio/virtio.c
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+++ b/hw/virtio/virtio.c
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@@ -423,6 +423,12 @@ void virtqueue_map_sg(struct iovec *sg, hwaddr *addr,
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     unsigned int i;
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     hwaddr len;
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+    if (num_sg >= VIRTQUEUE_MAX_SIZE) {
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+        error_report("virtio: map attempt out of bounds: %zd > %d",
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+                     num_sg, VIRTQUEUE_MAX_SIZE);
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+        exit(1);
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+    }
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+
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     for (i = 0; i < num_sg; i++) {
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         len = sg[i].iov_len;
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         sg[i].iov_base = cpu_physical_memory_map(addr[i], &len, is_write);
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-- 
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1.7.1
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