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, 21 insertions, 0 deletions

diff --git a/drivers/parport/Makefile b/drivers/parport/Makefile
new file mode 100644
index 000000000..d4a6b8908
--- /dev/null
+++ b/drivers/parport/Makefile
@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the kernel Parallel port device drivers.
+#
+
+parport-objs	:= share.o ieee1284.o ieee1284_ops.o procfs.o
+
+ifeq ($(CONFIG_PARPORT_1284),y)
+	parport-objs	+= daisy.o probe.o
+endif
+
+obj-$(CONFIG_PARPORT)		+= parport.o
+obj-$(CONFIG_PARPORT_PC)	+= parport_pc.o
+obj-$(CONFIG_PARPORT_SERIAL)	+= parport_serial.o
+obj-$(CONFIG_PARPORT_PC_PCMCIA) += parport_cs.o
+obj-$(CONFIG_PARPORT_AMIGA)	+= parport_amiga.o
+obj-$(CONFIG_PARPORT_MFC3)	+= parport_mfc3.o
+obj-$(CONFIG_PARPORT_ATARI)	+= parport_atari.o
+obj-$(CONFIG_PARPORT_SUNBPP)	+= parport_sunbpp.o
+obj-$(CONFIG_PARPORT_GSC)	+= parport_gsc.o
+obj-$(CONFIG_PARPORT_IP32)	+= parport_ip32.o