openrisc: fix arbitrary kernel memory access via or1k_atomic syscallgrafted

sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user
pointers, v1 and v2, and swaps the words they point to in hand-written
assembly.

    l.lwz   r29,0(r4)
    l.lwz   r27,0(r5)
    l.sw    0(r4),r27
    l.sw    0(r5),r29

The pointers are not checked with access_ok(). The four memory
accesses also have no exception table entries.

A caller passes a kernel address as either pointer, and the syscall
reads from and writes to it directly.

This gives an unprivileged process a kernel read/write primitive. It
overwrites kernel data such as the sys_call_table, gaining code
execution in kernel context.

Check both pointers before entering the critical section. Add fixups
for the four memory accesses so faults on valid but unmapped user
addresses return -EFAULT.

[shorne@gmail.com: fix comment style]
Fixes: 9d02a4283e9c ("OpenRISC: Boot code")
Cc: stable@vger.kernel.org
Signed-off-by: Ali Ahmet Memis <ali@iusegentoo.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

1 files changed, 83 insertions, 0 deletions

diff --git a/net/vmw_vsock/Kconfig b/net/vmw_vsock/Kconfig
new file mode 100644
index 000000000..8e803c482
--- /dev/null
+++ b/net/vmw_vsock/Kconfig
@@ -0,0 +1,83 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Vsock protocol
+#
+
+config VSOCKETS
+	tristate "Virtual Socket protocol"
+	help
+	  Virtual Socket Protocol is a socket protocol similar to TCP/IP
+	  allowing communication between Virtual Machines and hypervisor
+	  or host.
+
+	  You should also select one or more hypervisor-specific transports
+	  below.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called vsock. If unsure, say N.
+
+config VSOCKETS_DIAG
+	tristate "Virtual Sockets monitoring interface"
+	depends on VSOCKETS
+	default y
+	help
+	  Support for PF_VSOCK sockets monitoring interface used by the ss tool.
+	  If unsure, say Y.
+
+	  Enable this module so userspace applications can query open sockets.
+
+config VSOCKETS_LOOPBACK
+	tristate "Virtual Sockets loopback transport"
+	depends on VSOCKETS
+	default y
+	select VIRTIO_VSOCKETS_COMMON
+	help
+	  This module implements a loopback transport for Virtual Sockets,
+	  using vmw_vsock_virtio_transport_common.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called vsock_loopback. If unsure, say N.
+
+config VMWARE_VMCI_VSOCKETS
+	tristate "VMware VMCI transport for Virtual Sockets"
+	depends on VSOCKETS && VMWARE_VMCI
+	help
+	  This module implements a VMCI transport for Virtual Sockets.
+
+	  Enable this transport if your Virtual Machine runs on a VMware
+	  hypervisor.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called vmw_vsock_vmci_transport. If unsure, say N.
+
+config VIRTIO_VSOCKETS
+	tristate "virtio transport for Virtual Sockets"
+	depends on VSOCKETS && VIRTIO
+	select VIRTIO_VSOCKETS_COMMON
+	help
+	  This module implements a virtio transport for Virtual Sockets.
+
+	  Enable this transport if your Virtual Machine host supports Virtual
+	  Sockets over virtio.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called vmw_vsock_virtio_transport. If unsure, say N.
+
+config VIRTIO_VSOCKETS_COMMON
+	tristate
+	help
+	  This option is selected by any driver which needs to access
+	  the virtio_vsock.  The module will be called
+	  vmw_vsock_virtio_transport_common.
+
+config HYPERV_VSOCKETS
+	tristate "Hyper-V transport for Virtual Sockets"
+	depends on VSOCKETS && HYPERV_VMBUS
+	help
+	  This module implements a Hyper-V transport for Virtual Sockets.
+
+	  Enable this transport if your Virtual Machine host supports Virtual
+	  Sockets over Hyper-V VMBus.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called hv_sock. If unsure, say N.