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, 15 insertions, 0 deletions

diff --git a/drivers/pinctrl/meson/Makefile b/drivers/pinctrl/meson/Makefile
new file mode 100644
index 000000000..c92a65a83
--- /dev/null
+++ b/drivers/pinctrl/meson/Makefile
@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_PINCTRL_MESON) += pinctrl-meson.o
+obj-$(CONFIG_PINCTRL_MESON8_PMX) += pinctrl-meson8-pmx.o
+obj-$(CONFIG_PINCTRL_MESON8) += pinctrl-meson8.o
+obj-$(CONFIG_PINCTRL_MESON8B) += pinctrl-meson8b.o
+obj-$(CONFIG_PINCTRL_MESON_GXBB) += pinctrl-meson-gxbb.o
+obj-$(CONFIG_PINCTRL_MESON_GXL) += pinctrl-meson-gxl.o
+obj-$(CONFIG_PINCTRL_MESON_AXG_PMX) += pinctrl-meson-axg-pmx.o
+obj-$(CONFIG_PINCTRL_MESON_AXG) += pinctrl-meson-axg.o
+obj-$(CONFIG_PINCTRL_MESON_G12A) += pinctrl-meson-g12a.o
+obj-$(CONFIG_PINCTRL_MESON_A1) += pinctrl-meson-a1.o
+obj-$(CONFIG_PINCTRL_MESON_S4) += pinctrl-meson-s4.o
+obj-$(CONFIG_PINCTRL_AMLOGIC_A4) += pinctrl-amlogic-a4.o
+obj-$(CONFIG_PINCTRL_AMLOGIC_C3) += pinctrl-amlogic-c3.o
+obj-$(CONFIG_PINCTRL_AMLOGIC_T7) += pinctrl-amlogic-t7.o