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, 18 insertions, 0 deletions

diff --git a/drivers/dma/ti/Makefile b/drivers/dma/ti/Makefile
new file mode 100644
index 000000000..d376c117c
--- /dev/null
+++ b/drivers/dma/ti/Makefile
@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_TI_CPPI41) += cppi41.o
+obj-$(CONFIG_TI_EDMA) += edma.o
+obj-$(CONFIG_DMA_OMAP) += omap-dma.o
+obj-$(CONFIG_TI_K3_UDMA) += k3-udma.o
+obj-$(CONFIG_TI_K3_UDMA_GLUE_LAYER) += k3-udma-glue.o
+k3-psil-lib-objs := k3-psil.o \
+		    k3-psil-am654.o \
+		    k3-psil-j721e.o \
+		    k3-psil-j7200.o \
+		    k3-psil-am64.o \
+		    k3-psil-j721s2.o \
+		    k3-psil-am62.o \
+		    k3-psil-am62a.o \
+		    k3-psil-j784s4.o \
+		    k3-psil-am62p.o
+obj-$(CONFIG_TI_K3_PSIL) += k3-psil-lib.o
+obj-$(CONFIG_TI_DMA_CROSSBAR) += dma-crossbar.o