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, 37 insertions, 0 deletions

diff --git a/drivers/mtd/maps/Makefile b/drivers/mtd/maps/Makefile
new file mode 100644
index 000000000..01745eca1
--- /dev/null
+++ b/drivers/mtd/maps/Makefile
@@ -0,0 +1,37 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# linux/drivers/maps/Makefile
+#
+
+ifeq ($(CONFIG_MTD_COMPLEX_MAPPINGS),y)
+obj-$(CONFIG_MTD)		+= map_funcs.o
+endif
+
+# Chip mappings
+obj-$(CONFIG_MTD_CFI_FLAGADM)	+= cfi_flagadm.o
+obj-$(CONFIG_MTD_DC21285)	+= dc21285.o
+obj-$(CONFIG_MTD_L440GX)	+= l440gx.o
+obj-$(CONFIG_MTD_AMD76XROM)	+= amd76xrom.o
+obj-$(CONFIG_MTD_ESB2ROM)	+= esb2rom.o
+obj-$(CONFIG_MTD_ICHXROM)	+= ichxrom.o
+obj-$(CONFIG_MTD_CK804XROM)	+= ck804xrom.o
+obj-$(CONFIG_MTD_TSUNAMI)	+= tsunami_flash.o
+obj-$(CONFIG_MTD_PXA2XX)	+= pxa2xx-flash.o
+obj-$(CONFIG_MTD_PHYSMAP)	+= physmap.o
+physmap-y			:= physmap-core.o
+physmap-$(CONFIG_MTD_PHYSMAP_VERSATILE) += physmap-versatile.o
+physmap-$(CONFIG_MTD_PHYSMAP_GEMINI) += physmap-gemini.o
+physmap-$(CONFIG_MTD_PHYSMAP_IXP4XX) += physmap-ixp4xx.o
+obj-$(CONFIG_MTD_PISMO)		+= pismo.o
+obj-$(CONFIG_MTD_PCMCIA)	+= pcmciamtd.o
+obj-$(CONFIG_MTD_SA1100)	+= sa1100-flash.o
+obj-$(CONFIG_MTD_SBC_GXX)	+= sbc_gxx.o
+obj-$(CONFIG_MTD_SUN_UFLASH)	+= sun_uflash.o
+obj-$(CONFIG_MTD_SCx200_DOCFLASH)+= scx200_docflash.o
+obj-$(CONFIG_MTD_SOLUTIONENGINE)+= solutionengine.o
+obj-$(CONFIG_MTD_PCI)		+= pci.o
+obj-$(CONFIG_MTD_UCLINUX)	+= uclinux.o
+obj-$(CONFIG_MTD_SCB2_FLASH)	+= scb2_flash.o
+obj-$(CONFIG_MTD_PLATRAM)	+= plat-ram.o
+obj-$(CONFIG_MTD_VMU)		+= vmu-flash.o
+obj-$(CONFIG_MTD_LANTIQ)	+= lantiq-flash.o