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, 41 insertions, 0 deletions

diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile
new file mode 100644
index 000000000..3ee883c87
--- /dev/null
+++ b/drivers/memory/Makefile
@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for memory devices
+#
+
+obj-$(CONFIG_DDR)		+= jedec_ddr_data.o
+ifeq ($(CONFIG_DDR),y)
+obj-$(CONFIG_OF)		+= of_memory.o
+endif
+obj-$(CONFIG_ARM_PL172_MPMC)	+= pl172.o
+obj-$(CONFIG_ATMEL_EBI)		+= atmel-ebi.o
+obj-$(CONFIG_BRCMSTB_DPFE)	+= brcmstb_dpfe.o
+obj-$(CONFIG_BRCMSTB_MEMC)	+= brcmstb_memc.o
+obj-$(CONFIG_TI_AEMIF)		+= ti-aemif.o
+obj-$(CONFIG_TI_EMIF)		+= emif.o
+obj-$(CONFIG_OMAP_GPMC)		+= omap-gpmc.o
+obj-$(CONFIG_FSL_CORENET_CF)	+= fsl-corenet-cf.o
+obj-$(CONFIG_FSL_IFC)		+= fsl_ifc.o
+obj-$(CONFIG_MVEBU_DEVBUS)	+= mvebu-devbus.o
+obj-$(CONFIG_JZ4780_NEMC)	+= jz4780-nemc.o
+obj-$(CONFIG_MTK_SMI)		+= mtk-smi.o
+obj-$(CONFIG_DA8XX_DDRCTL)	+= da8xx-ddrctl.o
+obj-$(CONFIG_PL353_SMC)		+= pl353-smc.o
+obj-$(CONFIG_RENESAS_RPCIF)	+= renesas-rpc-if.o
+obj-$(CONFIG_STM32_FMC2_EBI)	+= stm32-fmc2-ebi.o
+obj-$(CONFIG_STM32_OMM)		+= stm32_omm.o
+
+obj-$(CONFIG_SAMSUNG_MC)	+= samsung/
+obj-$(CONFIG_TEGRA_MC)		+= tegra/
+obj-$(CONFIG_TI_EMIF_SRAM)	+= ti-emif-sram.o
+obj-$(CONFIG_FPGA_DFL_EMIF)	+= dfl-emif.o
+
+ti-emif-sram-objs		:= ti-emif-pm.o ti-emif-sram-pm.o
+
+$(obj)/ti-emif-sram-pm.o: $(obj)/ti-emif-asm-offsets.h
+
+$(obj)/ti-emif-asm-offsets.h: $(obj)/emif-asm-offsets.s FORCE
+	$(call filechk,offsets,__TI_EMIF_ASM_OFFSETS_H__)
+
+targets += emif-asm-offsets.s
+clean-files += ti-emif-asm-offsets.h