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, 32 insertions, 0 deletions

diff --git a/drivers/clk/sprd/Kconfig b/drivers/clk/sprd/Kconfig
new file mode 100644
index 000000000..2f19c8d58
--- /dev/null
+++ b/drivers/clk/sprd/Kconfig
@@ -0,0 +1,32 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config SPRD_COMMON_CLK
+	tristate "Clock support for Spreadtrum SoCs"
+	depends on ARCH_SPRD || COMPILE_TEST
+	default ARCH_SPRD
+	select REGMAP_MMIO
+
+if SPRD_COMMON_CLK
+
+# SoC Drivers
+
+config SPRD_SC9860_CLK
+	tristate "Support for the Spreadtrum SC9860 clocks"
+	depends on (ARM64 && ARCH_SPRD) || COMPILE_TEST
+	default ARM64 && ARCH_SPRD
+
+config SPRD_SC9863A_CLK
+	tristate "Support for the Spreadtrum SC9863A clocks"
+	depends on (ARM64 && ARCH_SPRD) || COMPILE_TEST
+	default ARM64 && ARCH_SPRD
+	help
+	  Support for the global clock controller on sc9863a devices.
+	  Say Y if you want to use peripheral devices on sc9863a SoC.
+
+config SPRD_UMS512_CLK
+	tristate "Support for the Spreadtrum UMS512 clocks"
+	depends on (ARM64 && ARCH_SPRD) || COMPILE_TEST
+	default ARM64 && ARCH_SPRD
+	help
+	  Support for the global clock controller on ums512 devices.
+	  Say Y if you want to use peripheral devices on ums512 SoC.
+endif