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, 15 insertions, 0 deletions

diff --git a/fs/ceph/Makefile b/fs/ceph/Makefile
new file mode 100644
index 000000000..ebb29d11a
--- /dev/null
+++ b/fs/ceph/Makefile
@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for CEPH filesystem.
+#
+
+obj-$(CONFIG_CEPH_FS) += ceph.o
+
+ceph-y := super.o inode.o dir.o file.o locks.o addr.o ioctl.o \
+	export.o caps.o snap.o xattr.o quota.o io.o \
+	mds_client.o mdsmap.o strings.o ceph_frag.o \
+	debugfs.o util.o metric.o subvolume_metrics.o
+
+ceph-$(CONFIG_CEPH_FSCACHE) += cache.o
+ceph-$(CONFIG_CEPH_FS_POSIX_ACL) += acl.o
+ceph-$(CONFIG_FS_ENCRYPTION) += crypto.o