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, 49 insertions, 0 deletions

diff --git a/drivers/usb/class/Kconfig b/drivers/usb/class/Kconfig
new file mode 100644
index 000000000..d3f5162bd
--- /dev/null
+++ b/drivers/usb/class/Kconfig
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# USB Class driver configuration
+#
+comment "USB Device Class drivers"
+
+config USB_ACM
+	tristate "USB Modem (CDC ACM) support"
+	depends on TTY
+	help
+	  This driver supports USB modems and ISDN adapters which support the
+	  Communication Device Class Abstract Control Model interface.
+	  Please read <file:Documentation/usb/acm.rst> for details.
+
+	  If your modem only reports "Cls=ff(vend.)" in the descriptors in
+	  /sys/kernel/debug/usb/devices, then your modem will not work with this
+	  driver.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cdc-acm.
+
+config USB_PRINTER
+	tristate "USB Printer support"
+	help
+	  Say Y here if you want to connect a USB printer to your computer's
+	  USB port.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called usblp.
+
+config USB_WDM
+	tristate "USB Wireless Device Management support"
+	help
+	  This driver supports the WMC Device Management functionality
+	  of cell phones compliant to the CDC WMC specification. You can use
+	  AT commands over this device.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cdc-wdm.
+
+config USB_TMC
+	tristate "USB Test and Measurement Class support"
+	help
+	  Say Y here if you want to connect a USB device that follows
+	  the USB.org specification for USB Test and Measurement devices
+	  to your computer's USB port.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called usbtmc.