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, 52 insertions, 0 deletions

diff --git a/Documentation/netlabel/introduction.rst b/Documentation/netlabel/introduction.rst
new file mode 100644
index 000000000..9333bbb0a
--- /dev/null
+++ b/Documentation/netlabel/introduction.rst
@@ -0,0 +1,52 @@
+=====================
+NetLabel Introduction
+=====================
+
+Paul Moore, paul.moore@hp.com
+
+August 2, 2006
+
+Overview
+========
+
+NetLabel is a mechanism which can be used by kernel security modules to attach
+security attributes to outgoing network packets generated from user space
+applications and read security attributes from incoming network packets.  It
+is composed of three main components, the protocol engines, the communication
+layer, and the kernel security module API.
+
+Protocol Engines
+================
+
+The protocol engines are responsible for both applying and retrieving the
+network packet's security attributes.  If any translation between the network
+security attributes and those on the host are required then the protocol
+engine will handle those tasks as well.  Other kernel subsystems should
+refrain from calling the protocol engines directly, instead they should use
+the NetLabel kernel security module API described below.
+
+Detailed information about each NetLabel protocol engine can be found in this
+directory.
+
+Communication Layer
+===================
+
+The communication layer exists to allow NetLabel configuration and monitoring
+from user space.  The NetLabel communication layer uses a message based
+protocol built on top of the Generic NETLINK transport mechanism.  The exact
+formatting of these NetLabel messages as well as the Generic NETLINK family
+names can be found in the 'net/netlabel/' directory as comments in the
+header files as well as in 'include/net/netlabel.h'.
+
+Security Module API
+===================
+
+The purpose of the NetLabel security module API is to provide a protocol
+independent interface to the underlying NetLabel protocol engines.  In addition
+to protocol independence, the security module API is designed to be completely
+LSM independent which should allow multiple LSMs to leverage the same code
+base.
+
+Detailed information about the NetLabel security module API can be found in the
+'include/net/netlabel.h' header file as well as the 'lsm_interface.txt' file
+found in this directory.