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, 40 insertions, 0 deletions

diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
new file mode 100644
index 000000000..4ddec2820
--- /dev/null
+++ b/drivers/firmware/Makefile
@@ -0,0 +1,40 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the linux kernel.
+#
+obj-$(CONFIG_ARM_SCPI_PROTOCOL)	+= arm_scpi.o
+obj-$(CONFIG_ARM_SDE_INTERFACE)	+= arm_sdei.o
+obj-$(CONFIG_DMI)		+= dmi_scan.o
+obj-$(CONFIG_DMI_SYSFS)		+= dmi-sysfs.o
+obj-$(CONFIG_EDD)		+= edd.o
+obj-$(CONFIG_DMIID)		+= dmi-id.o
+obj-$(CONFIG_INTEL_STRATIX10_SERVICE) += stratix10-svc.o
+obj-$(CONFIG_INTEL_STRATIX10_RSU)     += stratix10-rsu.o
+obj-$(CONFIG_ISCSI_IBFT_FIND)	+= iscsi_ibft_find.o
+obj-$(CONFIG_ISCSI_IBFT)	+= iscsi_ibft.o
+obj-$(CONFIG_FIRMWARE_MEMMAP)	+= memmap.o
+obj-$(CONFIG_MTK_ADSP_IPC)	+= mtk-adsp-ipc.o
+obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o
+obj-$(CONFIG_FW_CFG_SYSFS)	+= qemu_fw_cfg.o
+obj-$(CONFIG_SYSFB)		+= sysfb.o
+obj-$(CONFIG_SYSFB_SIMPLEFB)	+= sysfb_simplefb.o
+obj-$(CONFIG_TH1520_AON_PROTOCOL) += thead,th1520-aon.o
+obj-$(CONFIG_TI_SCI_PROTOCOL)	+= ti_sci.o
+obj-$(CONFIG_TRUSTED_FOUNDATIONS) += trusted_foundations.o
+obj-$(CONFIG_TURRIS_MOX_RWTM)	+= turris-mox-rwtm.o
+
+obj-y				+= arm_ffa/
+obj-y				+= arm_scmi/
+obj-y				+= broadcom/
+obj-y				+= cirrus/
+obj-y				+= meson/
+obj-y				+= microchip/
+obj-$(CONFIG_GOOGLE_FIRMWARE)	+= google/
+obj-y				+= efi/
+obj-y				+= imx/
+obj-y				+= psci/
+obj-y				+= qcom/
+obj-y				+= samsung/
+obj-y				+= smccc/
+obj-y				+= tegra/
+obj-y				+= xilinx/