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, 37 insertions, 0 deletions

diff --git a/net/bridge/Makefile b/net/bridge/Makefile
new file mode 100644
index 000000000..1203dc19e
--- /dev/null
+++ b/net/bridge/Makefile
@@ -0,0 +1,37 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the IEEE 802.1d ethernet bridging layer.
+#
+
+obj-$(CONFIG_BRIDGE) += bridge.o
+
+bridge-y	:= br.o br_device.o br_fdb.o br_forward.o br_if.o br_input.o \
+			br_ioctl.o br_stp.o br_stp_bpdu.o \
+			br_stp_if.o br_stp_timer.o br_netlink.o \
+			br_netlink_tunnel.o br_arp_nd_proxy.o
+
+bridge-$(CONFIG_SYSFS) += br_sysfs_if.o br_sysfs_br.o
+
+bridge-$(subst m,y,$(CONFIG_BRIDGE_NETFILTER)) += br_nf_core.o
+
+br_netfilter-y := br_netfilter_hooks.o
+br_netfilter-$(subst m,y,$(CONFIG_IPV6)) += br_netfilter_ipv6.o
+obj-$(CONFIG_BRIDGE_NETFILTER) += br_netfilter.o
+
+bridge-$(CONFIG_BRIDGE_IGMP_SNOOPING) += br_multicast.o br_mdb.o br_multicast_eht.o
+
+bridge-$(CONFIG_BRIDGE_VLAN_FILTERING) += br_vlan.o br_vlan_tunnel.o br_vlan_options.o br_mst.o
+
+bridge-$(CONFIG_NET_SWITCHDEV) += br_switchdev.o
+
+obj-$(CONFIG_NETFILTER) += netfilter/
+
+bridge-$(CONFIG_BRIDGE_MRP)	+= br_mrp_switchdev.o br_mrp.o br_mrp_netlink.o
+
+bridge-$(CONFIG_BRIDGE_CFM)	+= br_cfm.o br_cfm_netlink.o
+
+ifdef CONFIG_GCOV_PROFILE_NETFILTER
+GCOV_PROFILE_br_nf_core.o := y
+GCOV_PROFILE_br_netfilter_hooks.o := y
+GCOV_PROFILE_br_netfilter_ipv6.o := y
+endif