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, 85 insertions, 0 deletions

diff --git a/net/bridge/Kconfig b/net/bridge/Kconfig
new file mode 100644
index 000000000..318715c8f
--- /dev/null
+++ b/net/bridge/Kconfig
@@ -0,0 +1,85 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# 802.1d Ethernet Bridging
+#
+
+config BRIDGE
+	tristate "802.1d Ethernet Bridging"
+	select LLC
+	select STP
+	help
+	  If you say Y here, then your Linux box will be able to act as an
+	  Ethernet bridge, which means that the different Ethernet segments it
+	  is connected to will appear as one Ethernet to the participants.
+	  Several such bridges can work together to create even larger
+	  networks of Ethernets using the IEEE 802.1 spanning tree algorithm.
+	  As this is a standard, Linux bridges will cooperate properly with
+	  other third party bridge products.
+
+	  In order to use the Ethernet bridge, you'll need the bridge
+	  configuration tools; see <file:Documentation/networking/bridge.rst>
+	  for location. Please read the Bridge mini-HOWTO for more
+	  information.
+
+	  If you enable iptables support along with the bridge support then you
+	  turn your bridge into a bridging IP firewall.
+	  iptables will then see the IP packets being bridged, so you need to
+	  take this into account when setting up your firewall rules.
+	  Enabling arptables support when bridging will let arptables see
+	  bridged ARP traffic in the arptables FORWARD chain.
+
+	  To compile this code as a module, choose M here: the module
+	  will be called bridge.
+
+	  If unsure, say N.
+
+config BRIDGE_IGMP_SNOOPING
+	bool "IGMP/MLD snooping"
+	depends on BRIDGE
+	depends on INET
+	default y
+	help
+	  If you say Y here, then the Ethernet bridge will be able selectively
+	  forward multicast traffic based on IGMP/MLD traffic received from
+	  each port.
+
+	  Say N to exclude this support and reduce the binary size.
+
+	  If unsure, say Y.
+
+config BRIDGE_VLAN_FILTERING
+	bool "VLAN filtering"
+	depends on BRIDGE
+	depends on VLAN_8021Q
+	default n
+	help
+	  If you say Y here, then the Ethernet bridge will be able selectively
+	  receive and forward traffic based on VLAN information in the packet
+	  any VLAN information configured on the bridge port or bridge device.
+
+	  Say N to exclude this support and reduce the binary size.
+
+	  If unsure, say Y.
+
+config BRIDGE_MRP
+	bool "MRP protocol"
+	depends on BRIDGE
+	default n
+	help
+	  If you say Y here, then the Ethernet bridge will be able to run MRP
+	  protocol to detect loops
+
+	  Say N to exclude this support and reduce the binary size.
+
+	  If unsure, say N.
+
+config BRIDGE_CFM
+	bool "CFM protocol"
+	depends on BRIDGE
+	help
+	  If you say Y here, then the Ethernet bridge will be able to run CFM
+	  protocol according to 802.1Q section 12.14
+
+	  Say N to exclude this support and reduce the binary size.
+
+	  If unsure, say N.