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, 48 insertions, 0 deletions

diff --git a/arch/m68k/coldfire/Makefile b/arch/m68k/coldfire/Makefile
new file mode 100644
index 000000000..c56bc0dc7
--- /dev/null
+++ b/arch/m68k/coldfire/Makefile
@@ -0,0 +1,48 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the m68knommu kernel.
+#
+
+#
+# If you want to play with the HW breakpoints then you will
+# need to add define this,  which will give you a stack backtrace
+# on the console port whenever a DBG interrupt occurs. You have to
+# set up you HW breakpoints to trigger a DBG interrupt:
+#
+# ccflags-y := -DTRAP_DBG_INTERRUPT
+# asflags-y := -DTRAP_DBG_INTERRUPT
+#
+
+asflags-$(CONFIG_FULLDEBUG) := -DDEBUGGER_COMPATIBLE_CACHE=1
+
+obj-$(CONFIG_COLDFIRE)	+= cache.o clk.o device.o entry.o vectors.o
+obj-$(CONFIG_M5206)	+= m5206.o intc.o reset.o
+obj-$(CONFIG_M5206e)	+= m5206.o intc.o reset.o
+obj-$(CONFIG_M520x)	+= m520x.o intc-simr.o reset.o
+obj-$(CONFIG_M523x)	+= m523x.o dma_timer.o intc-2.o reset.o
+obj-$(CONFIG_M5249)	+= m5249.o intc.o intc-5249.o reset.o
+obj-$(CONFIG_M525x)	+= m525x.o intc.o intc-525x.o reset.o
+obj-$(CONFIG_M527x)	+= m527x.o intc-2.o reset.o
+obj-$(CONFIG_M5272)	+= m5272.o intc-5272.o
+obj-$(CONFIG_M528x)	+= m528x.o intc-2.o reset.o
+obj-$(CONFIG_M5307)	+= m5307.o intc.o reset.o
+obj-$(CONFIG_M53xx)	+= m53xx.o intc-simr.o reset.o
+obj-$(CONFIG_M5407)	+= m5407.o intc.o reset.o
+obj-$(CONFIG_M54xx)	+= m54xx.o intc-2.o
+obj-$(CONFIG_M5441x)	+= m5441x.o intc-simr.o reset.o
+
+obj-$(CONFIG_COLDFIRE_PIT_TIMER) += pit.o
+obj-$(CONFIG_COLDFIRE_TIMERS)	 += timers.o
+obj-$(CONFIG_COLDFIRE_SLTIMERS)	 += sltimers.o
+
+obj-$(CONFIG_NETtel)	+= nettel.o
+obj-$(CONFIG_CLEOPATRA)	+= nettel.o
+obj-$(CONFIG_FIREBEE)	+= firebee.o
+obj-$(CONFIG_MCF8390)	+= mcf8390.o
+obj-$(CONFIG_AMCORE)	+= amcore.o
+obj-$(CONFIG_STMARK2)	+= stmark2.o
+
+obj-$(CONFIG_PCI)	+= pci.o
+
+obj-y			+= gpio.o
+obj-y			+= head.o