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, 19 insertions, 0 deletions

diff --git a/drivers/clk/bcm/Makefile b/drivers/clk/bcm/Makefile
new file mode 100644
index 000000000..d0b6f4b1f
--- /dev/null
+++ b/drivers/clk/bcm/Makefile
@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_CLK_BCM_63XX)	+= clk-bcm63xx.o
+obj-$(CONFIG_CLK_BCM_63XX_GATE)	+= clk-bcm63xx-gate.o
+obj-$(CONFIG_CLK_BCM63268_TIMER) += clk-bcm63268-timer.o
+obj-$(CONFIG_CLK_BCM_KONA)	+= clk-kona.o
+obj-$(CONFIG_CLK_BCM_KONA)	+= clk-kona-setup.o
+obj-$(CONFIG_CLK_BCM_KONA)	+= clk-bcm281xx.o
+obj-$(CONFIG_CLK_BCM_KONA)	+= clk-bcm21664.o
+obj-$(CONFIG_COMMON_CLK_IPROC)	+= clk-iproc-armpll.o clk-iproc-pll.o clk-iproc-asiu.o
+obj-$(CONFIG_CLK_BCM2711_DVP)	+= clk-bcm2711-dvp.o
+obj-$(CONFIG_CLK_BCM2835)	+= clk-bcm2835.o
+obj-$(CONFIG_CLK_BCM2835)	+= clk-bcm2835-aux.o
+obj-$(CONFIG_CLK_RASPBERRYPI)	+= clk-raspberrypi.o
+obj-$(CONFIG_ARCH_BCM_53573)	+= clk-bcm53573-ilp.o
+obj-$(CONFIG_CLK_BCM_CYGNUS)	+= clk-cygnus.o
+obj-$(CONFIG_CLK_BCM_HR2)	+= clk-hr2.o
+obj-$(CONFIG_CLK_BCM_NSP)	+= clk-nsp.o
+obj-$(CONFIG_CLK_BCM_NS2)	+= clk-ns2.o
+obj-$(CONFIG_CLK_BCM_SR)	+= clk-sr.o