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ashutoshxgregkh
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misc: mic: Fix for double fetch security bug in VOP driver
The MIC VOP driver does two successive reads from user space to read a variable length data structure. Kernel memory corruption can result if the data structure changes between the two reads. This patch disallows the chance of this happening. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=116651 Reported by: Pengfei Wang <wpengfeinudt@gmail.com> Reviewed-by: Sudeep Dutt <sudeep.dutt@intel.com> Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Diff for: drivers/misc/mic/vop/vop_vringh.c

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@@ -945,6 +945,11 @@ static long vop_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
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ret = -EFAULT;
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goto free_ret;
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}
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/* Ensure desc has not changed between the two reads */
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if (memcmp(&dd, dd_config, sizeof(dd))) {
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ret = -EINVAL;
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goto free_ret;
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}
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mutex_lock(&vdev->vdev_mutex);
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mutex_lock(&vi->vop_mutex);
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ret = vop_virtio_add_device(vdev, dd_config);

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