[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-devel] [PATCH] virtio-blk: refuse SG_IO requests with scsi=off

From: Paolo Bonzini
Subject: [Qemu-devel] [PATCH] virtio-blk: refuse SG_IO requests with scsi=off
Date: Fri, 23 Dec 2011 15:39:03 +0100

QEMU does have a "scsi" option (to be used like -device
virtio-blk-pci,drive=foo,scsi=off).  However, it only
masks the feature bit, and does not reject the command
if a malicious guest disregards the feature bits and
issues a request.

Without this patch, using scsi=off does not protect you
from CVE-2011-4127.

Signed-off-by: Paolo Bonzini <address@hidden>
 hw/virtio-blk.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
index b70d116..6cd3164 100644
--- a/hw/virtio-blk.c
+++ b/hw/virtio-blk.c
@@ -153,6 +153,12 @@ static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
     int status;
     int i;
+    if ((req->dev->vdev.guest_features & (1 << VIRTIO_BLK_F_SCSI)) == 0) {
+        virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP);
+        g_free(req);
+        return;
+    }
      * We require at least one output segment each for the virtio_blk_outhdr
      * and the SCSI command block.

reply via email to

[Prev in Thread] Current Thread [Next in Thread]