Commit 82dc4afd authored by Ashutosh Dixit's avatar Ashutosh Dixit Committed by Greg Kroah-Hartman

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: default avatarSudeep Dutt <sudeep.dutt@intel.com>
Signed-off-by: default avatarAshutosh Dixit <ashutosh.dixit@intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c3b46c73
...@@ -945,6 +945,11 @@ static long vop_ioctl(struct file *f, unsigned int cmd, unsigned long arg) ...@@ -945,6 +945,11 @@ static long vop_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
ret = -EFAULT; ret = -EFAULT;
goto free_ret; goto free_ret;
} }
/* Ensure desc has not changed between the two reads */
if (memcmp(&dd, dd_config, sizeof(dd))) {
ret = -EINVAL;
goto free_ret;
}
mutex_lock(&vdev->vdev_mutex); mutex_lock(&vdev->vdev_mutex);
mutex_lock(&vi->vop_mutex); mutex_lock(&vi->vop_mutex);
ret = vop_virtio_add_device(vdev, dd_config); ret = vop_virtio_add_device(vdev, dd_config);
......
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