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, 30 insertions, 0 deletions

diff --git a/drivers/usb/cdns3/Makefile b/drivers/usb/cdns3/Makefile
new file mode 100644
index 000000000..b2e4ba6a4
--- /dev/null
+++ b/drivers/usb/cdns3/Makefile
@@ -0,0 +1,30 @@
+# SPDX-License-Identifier: GPL-2.0
+# define_trace.h needs to know how to find our header
+CFLAGS_cdns3-trace.o				:= -I$(src)
+CFLAGS_cdnsp-trace.o				:= -I$(src)
+
+obj-$(CONFIG_USB_CDNS3)			+= cdns.o
+
+cdns-y					:= core.o drd.o cdns3-plat.o
+cdns-$(CONFIG_USB_CDNS3_HOST)		+= host.o
+
+ifneq ($(CONFIG_USB_CDNS3_GADGET),)
+cdns-y					+= cdns3-gadget.o cdns3-ep0.o \
+					   cdnsp-ring.o cdnsp-gadget.o \
+					   cdnsp-mem.o cdnsp-ep0.o
+endif
+
+ifneq ($(CONFIG_TRACING),)
+ifneq ($(CONFIG_USB_CDNS3_GADGET),)
+cdns-y					+= cdns3-trace.o cdnsp-trace.o
+endif
+endif
+
+##
+# Platform-specific glue layers (PCI wrappers, SoC integration)
+##
+obj-$(CONFIG_USB_CDNS3_PCI_WRAP)		+= cdns3-pci-wrap.o
+obj-$(CONFIG_USB_CDNSP_PCI)			+= cdnsp-pci.o
+obj-$(CONFIG_USB_CDNS3_TI)			+= cdns3-ti.o
+obj-$(CONFIG_USB_CDNS3_IMX)			+= cdns3-imx.o
+obj-$(CONFIG_USB_CDNS3_STARFIVE)		+= cdns3-starfive.o