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, 20 insertions, 0 deletions

diff --git a/sound/Makefile b/sound/Makefile
new file mode 100644
index 000000000..5942311a4
--- /dev/null
+++ b/sound/Makefile
@@ -0,0 +1,20 @@
+# SPDX-License-Identifier: GPL-2.0
+# Makefile for the Linux sound card driver
+#
+
+obj-$(CONFIG_SOUND) += soundcore.o
+obj-$(CONFIG_DMASOUND) += oss/dmasound/
+obj-$(CONFIG_SND) += core/ i2c/ drivers/ isa/ pci/ ppc/ arm/ sh/ synth/ usb/ \
+	firewire/ sparc/ spi/ parisc/ pcmcia/ mips/ soc/ atmel/ hda/ x86/ xen/ \
+	virtio/
+obj-$(CONFIG_SND_AOA) += aoa/
+
+# This one must be compilable even if sound is configured out
+obj-$(CONFIG_AC97_BUS) += ac97_bus.o
+obj-$(CONFIG_AC97_BUS_NEW) += ac97/
+
+ifeq ($(CONFIG_SND),y)
+  obj-y += last.o
+endif
+
+soundcore-y  := sound_core.o