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, 22 insertions, 0 deletions

diff --git a/drivers/input/rmi4/Makefile b/drivers/input/rmi4/Makefile
new file mode 100644
index 000000000..35ae29f72
--- /dev/null
+++ b/drivers/input/rmi4/Makefile
@@ -0,0 +1,22 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_RMI4_CORE) += rmi_core.o
+rmi_core-y := rmi_bus.o rmi_driver.o rmi_f01.o
+
+rmi_core-$(CONFIG_RMI4_2D_SENSOR) += rmi_2d_sensor.o
+
+# Function drivers
+rmi_core-$(CONFIG_RMI4_F03) += rmi_f03.o
+rmi_core-$(CONFIG_RMI4_F11) += rmi_f11.o
+rmi_core-$(CONFIG_RMI4_F12) += rmi_f12.o
+rmi_core-$(CONFIG_RMI4_F1A) += rmi_f1a.o
+rmi_core-$(CONFIG_RMI4_F21) += rmi_f21.o
+rmi_core-$(CONFIG_RMI4_F30) += rmi_f30.o
+rmi_core-$(CONFIG_RMI4_F34) += rmi_f34.o rmi_f34v7.o
+rmi_core-$(CONFIG_RMI4_F3A) += rmi_f3a.o
+rmi_core-$(CONFIG_RMI4_F54) += rmi_f54.o
+rmi_core-$(CONFIG_RMI4_F55) += rmi_f55.o
+
+# Transports
+obj-$(CONFIG_RMI4_I2C) += rmi_i2c.o
+obj-$(CONFIG_RMI4_SPI) += rmi_spi.o
+obj-$(CONFIG_RMI4_SMB) += rmi_smbus.o