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, 44 insertions, 0 deletions

diff --git a/drivers/misc/mei/Makefile b/drivers/misc/mei/Makefile
new file mode 100644
index 000000000..9a6aa3359
--- /dev/null
+++ b/drivers/misc/mei/Makefile
@@ -0,0 +1,44 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (c) 2010-2019, Intel Corporation. All rights reserved.
+# Makefile - Intel Management Engine Interface (Intel MEI) Linux driver
+#
+obj-$(CONFIG_INTEL_MEI) += mei.o
+mei-objs := init.o
+mei-objs += hbm.o
+mei-objs += interrupt.o
+mei-objs += client.o
+mei-objs += main.o
+mei-objs += dma-ring.o
+mei-objs += bus.o
+mei-objs += bus-fixup.o
+mei-$(CONFIG_DEBUG_FS) += debugfs.o
+
+obj-$(CONFIG_INTEL_MEI_ME) += mei-me.o
+mei-me-objs := pci-me.o
+mei-me-objs += hw-me.o
+
+obj-$(CONFIG_INTEL_MEI_GSC) += mei-gsc.o
+mei-gsc-objs := gsc-me.o
+
+obj-$(CONFIG_INTEL_MEI_CSC) += mei-csc.o
+mei-csc-objs := pci-csc.o
+
+obj-$(CONFIG_INTEL_MEI_TXE) += mei-txe.o
+mei-txe-objs := pci-txe.o
+mei-txe-objs += hw-txe.o
+
+mei-$(CONFIG_EVENT_TRACING) += mei-trace.o
+CFLAGS_mei-trace.o = -I$(src)
+
+obj-$(CONFIG_INTEL_MEI_HDCP) += hdcp/
+obj-$(CONFIG_INTEL_MEI_PXP) += pxp/
+obj-$(CONFIG_INTEL_MEI_GSC_PROXY) += gsc_proxy/
+obj-$(CONFIG_INTEL_MEI_LB) += mei_lb.o
+
+obj-$(CONFIG_INTEL_MEI_VSC_HW) += mei-vsc-hw.o
+mei-vsc-hw-y := vsc-tp.o
+mei-vsc-hw-y += vsc-fw-loader.o
+
+obj-$(CONFIG_INTEL_MEI_VSC) += mei-vsc.o
+mei-vsc-y := platform-vsc.o