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, 34 insertions, 0 deletions

diff --git a/net/rfkill/Kconfig b/net/rfkill/Kconfig
new file mode 100644
index 000000000..83a7af898
--- /dev/null
+++ b/net/rfkill/Kconfig
@@ -0,0 +1,34 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# RF switch subsystem configuration
+#
+menuconfig RFKILL
+	tristate "RF switch subsystem support"
+	help
+	  Say Y here if you want to have control over RF switches
+	  found on many WiFi and Bluetooth cards.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called rfkill.
+
+# LED trigger support
+config RFKILL_LEDS
+	bool
+	depends on RFKILL
+	depends on LEDS_TRIGGERS = y || RFKILL = LEDS_TRIGGERS
+	default y
+
+config RFKILL_INPUT
+	bool "RF switch input support" if EXPERT
+	depends on RFKILL
+	depends on INPUT = y || RFKILL = INPUT
+	default y if !EXPERT
+
+config RFKILL_GPIO
+	tristate "GPIO RFKILL driver"
+	depends on RFKILL
+	depends on GPIOLIB || COMPILE_TEST
+	default n
+	help
+	  If you say yes here you get support of a generic gpio RFKILL
+	  driver.