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, 38 insertions, 0 deletions

diff --git a/drivers/s390/crypto/Makefile b/drivers/s390/crypto/Makefile
new file mode 100644
index 000000000..e83c6603c
--- /dev/null
+++ b/drivers/s390/crypto/Makefile
@@ -0,0 +1,38 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# S/390 crypto devices
+#
+
+ap-objs := ap_bus.o ap_card.o ap_queue.o
+obj-$(CONFIG_AP) += ap.o
+# zcrypt_api.o and zcrypt_msgtype*.o depend on ap.o
+zcrypt-objs := zcrypt_api.o zcrypt_card.o zcrypt_queue.o
+zcrypt-objs += zcrypt_msgtype6.o zcrypt_msgtype50.o
+zcrypt-objs += zcrypt_ccamisc.o zcrypt_ep11misc.o
+obj-$(CONFIG_ZCRYPT) += zcrypt.o
+# adapter drivers depend on ap.o and zcrypt.o
+obj-$(CONFIG_ZCRYPT) += zcrypt_cex4.o
+
+# pkey base and api module
+pkey-objs := pkey_base.o pkey_api.o pkey_sysfs.o
+obj-$(CONFIG_PKEY) += pkey.o
+
+# pkey cca handler module
+pkey-cca-objs := pkey_cca.o
+obj-$(CONFIG_PKEY_CCA) += pkey-cca.o
+
+# pkey ep11 handler module
+pkey-ep11-objs := pkey_ep11.o
+obj-$(CONFIG_PKEY_EP11) += pkey-ep11.o
+
+# pkey pckmo handler module
+pkey-pckmo-objs := pkey_pckmo.o
+obj-$(CONFIG_PKEY_PCKMO) += pkey-pckmo.o
+
+# pkey uv handler module
+pkey-uv-objs := pkey_uv.o
+obj-$(CONFIG_PKEY_UV) += pkey-uv.o
+
+# adjunct processor matrix
+vfio_ap-objs := vfio_ap_drv.o vfio_ap_ops.o
+obj-$(CONFIG_VFIO_AP) += vfio_ap.o