Blame SOURCES/kvm-Allow-mismatched-virtio-config-len.patch

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From 88fd47b4c3a1a272d7e21ba0e7358e0a4e9ecf88 Mon Sep 17 00:00:00 2001
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From: Dr. David Alan Gilbert (git) <dgilbert@redhat.com>
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Date: Mon, 30 Jun 2014 11:10:01 +0200
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Subject: [PATCH] Allow mismatched virtio config-len
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RH-Author: Dr. David Alan Gilbert (git) <dgilbert@redhat.com>
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Message-id: <1404126601-23992-2-git-send-email-dgilbert@redhat.com>
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Patchwork-id: 59407
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O-Subject: [RHEL-7.0.z qemu-kvm PATCH 1/1] Allow mismatched virtio config-len
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Bugzilla: 1095782
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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RH-Acked-by: Juan Quintela <quintela@redhat.com>
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RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>
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From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
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Commit 'virtio: validate config_len on load' restricted config_len
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loaded from the wire to match the config_len that the device had.
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Unfortunately, there are cases where this isn't true, the one
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we found it on was the wce addition in virtio-blk.
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Allow mismatched config-lengths:
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   *) If the version on the wire is shorter then fine
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   *) If the version on the wire is longer, load what we have space
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      for and skip the rest.
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(This is mst@redhat.com's rework of what I originally posted)
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Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
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Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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(cherry picked from commit 2f5732e9648fcddc8759a8fd25c0b41a38352be6)
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---
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 hw/virtio/virtio.c | 16 +++++++++++-----
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 1 file changed, 11 insertions(+), 5 deletions(-)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 hw/virtio/virtio.c |   16 +++++++++++-----
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 1 files changed, 11 insertions(+), 5 deletions(-)
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diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
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index 44309c2..132b5af 100644
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--- a/hw/virtio/virtio.c
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+++ b/hw/virtio/virtio.c
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@@ -886,12 +886,18 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f)
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         return -1;
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     }
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     config_len = qemu_get_be32(f);
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-    if (config_len != vdev->config_len) {
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-        error_report("Unexpected config length 0x%x. Expected 0x%zx",
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-                     config_len, vdev->config_len);
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-        return -1;
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+
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+    /*
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+     * There are cases where the incoming config can be bigger or smaller
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+     * than what we have; so load what we have space for, and skip
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+     * any excess that's in the stream.
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+     */
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+    qemu_get_buffer(f, vdev->config, MIN(config_len, vdev->config_len));
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+
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+    while (config_len > vdev->config_len) {
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+        qemu_get_byte(f);
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+        config_len--;
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     }
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-    qemu_get_buffer(f, vdev->config, vdev->config_len);
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     num = qemu_get_be32(f);
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-- 
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1.7.1
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