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, 62 insertions, 0 deletions

diff --git a/drivers/usb/isp1760/Kconfig b/drivers/usb/isp1760/Kconfig
new file mode 100644
index 000000000..e19178f3c
--- /dev/null
+++ b/drivers/usb/isp1760/Kconfig
@@ -0,0 +1,62 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config USB_ISP1760
+	tristate "NXP ISP 1760/1761/1763 support"
+	depends on USB || USB_GADGET
+	select REGMAP_MMIO
+	help
+	  Say Y or M here if your system as an ISP1760/1763 USB host controller
+	  or an ISP1761 USB dual-role controller.
+
+	  This driver does not support isochronous transfers or OTG.
+	  This USB controller is usually attached to a non-DMA-Master
+	  capable bus. NXP's eval kit brings this chip on PCI card
+	  where the chip itself is behind a PLB to simulate such
+	  a bus.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called isp1760.
+
+config USB_ISP1760_HCD
+	bool
+
+config USB_ISP1761_UDC
+	bool
+
+if USB_ISP1760
+
+choice
+	prompt "ISP1760 Mode Selection"
+	default USB_ISP1760_DUAL_ROLE if (USB && USB_GADGET)
+	default USB_ISP1760_HOST_ROLE if (USB && !USB_GADGET)
+	default USB_ISP1760_GADGET_ROLE if (!USB && USB_GADGET)
+
+config USB_ISP1760_HOST_ROLE
+	bool "Host only mode"
+	depends on USB=y || USB=USB_ISP1760
+	select USB_ISP1760_HCD
+	help
+	  Select this if you want to use the ISP1760 in host mode only. The
+	  gadget function will be disabled.
+
+config USB_ISP1760_GADGET_ROLE
+	bool "Gadget only mode"
+	depends on USB_GADGET=y || USB_GADGET=USB_ISP1760
+	select USB_ISP1761_UDC
+	help
+	  Select this if you want to use the ISP1760 in peripheral mode only.
+	  The host function will be disabled.
+
+config USB_ISP1760_DUAL_ROLE
+	bool "Dual Role mode"
+	depends on USB=y || USB=USB_ISP1760
+	depends on USB_GADGET=y || USB_GADGET=USB_ISP1760
+	select USB_ISP1760_HCD
+	select USB_ISP1761_UDC
+	help
+	  Select this if you want to use the ISP1760 in both host and
+	  peripheral modes.
+
+endchoice
+
+endif