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, 49 insertions, 0 deletions

diff --git a/fs/ceph/Kconfig b/fs/ceph/Kconfig
new file mode 100644
index 000000000..3d64a316c
--- /dev/null
+++ b/fs/ceph/Kconfig
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config CEPH_FS
+	tristate "Ceph distributed file system"
+	depends on INET
+	select CEPH_LIB
+	select NETFS_SUPPORT
+	select FS_ENCRYPTION_ALGS if FS_ENCRYPTION
+	default n
+	help
+	  Choose Y or M here to include support for mounting the
+	  experimental Ceph distributed file system.  Ceph is an extremely
+	  scalable file system designed to provide high performance,
+	  reliable access to petabytes of storage.
+
+	  More information at https://ceph.io/.
+
+	  If unsure, say N.
+
+if CEPH_FS
+config CEPH_FSCACHE
+	bool "Enable Ceph client caching support"
+	depends on CEPH_FS=m && FSCACHE || CEPH_FS=y && FSCACHE=y
+	help
+	  Choose Y here to enable persistent, read-only local
+	  caching support for Ceph clients using FS-Cache
+
+endif
+
+config CEPH_FS_POSIX_ACL
+	bool "Ceph POSIX Access Control Lists"
+	depends on CEPH_FS
+	select FS_POSIX_ACL
+	help
+	  POSIX Access Control Lists (ACLs) support permissions for users and
+	  groups beyond the owner/group/world scheme.
+
+	  If you don't know what Access Control Lists are, say N
+
+config CEPH_FS_SECURITY_LABEL
+	bool "CephFS Security Labels"
+	depends on CEPH_FS && SECURITY
+	help
+	  Security labels support alternative access control models
+	  implemented by security modules like SELinux. This option
+	  enables an extended attribute handler for file security
+	  labels in the Ceph filesystem.
+
+	  If you are not using a security module that requires using
+	  extended attributes for file security labels, say N.