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, 162 insertions, 0 deletions

diff --git a/Documentation/networking/kapi.rst b/Documentation/networking/kapi.rst
new file mode 100644
index 000000000..98682b9a1
--- /dev/null
+++ b/Documentation/networking/kapi.rst
@@ -0,0 +1,162 @@
+=========================================
+Linux Networking and Network Devices APIs
+=========================================
+
+Linux Networking
+================
+
+Networking Base Types
+---------------------
+
+.. kernel-doc:: include/linux/net.h
+   :internal:
+
+Socket Buffer Functions
+-----------------------
+
+.. kernel-doc:: include/linux/skbuff.h
+   :internal:
+
+.. kernel-doc:: include/net/sock.h
+   :internal:
+
+.. kernel-doc:: net/socket.c
+   :export:
+
+.. kernel-doc:: net/core/skbuff.c
+   :export:
+
+.. kernel-doc:: net/core/sock.c
+   :export:
+
+.. kernel-doc:: net/core/datagram.c
+   :export:
+
+.. kernel-doc:: net/core/stream.c
+   :export:
+
+Socket Filter
+-------------
+
+.. kernel-doc:: net/core/filter.c
+   :export:
+
+Generic Network Statistics
+--------------------------
+
+.. kernel-doc:: include/uapi/linux/gen_stats.h
+   :internal:
+
+.. kernel-doc:: net/core/gen_stats.c
+   :export:
+
+.. kernel-doc:: net/core/gen_estimator.c
+   :export:
+
+SUN RPC subsystem
+-----------------
+
+.. kernel-doc:: net/sunrpc/xdr.c
+   :export:
+
+.. kernel-doc:: net/sunrpc/svc_xprt.c
+   :export:
+
+.. kernel-doc:: net/sunrpc/xprt.c
+   :export:
+
+.. kernel-doc:: net/sunrpc/sched.c
+   :export:
+
+.. kernel-doc:: net/sunrpc/socklib.c
+   :export:
+
+.. kernel-doc:: net/sunrpc/stats.c
+   :export:
+
+.. kernel-doc:: net/sunrpc/rpc_pipe.c
+   :export:
+
+.. kernel-doc:: net/sunrpc/rpcb_clnt.c
+   :export:
+
+.. kernel-doc:: net/sunrpc/clnt.c
+   :export:
+
+Network device support
+======================
+
+Driver Support
+--------------
+
+.. kernel-doc:: net/core/dev.c
+   :export:
+
+.. kernel-doc:: net/ethernet/eth.c
+   :export:
+
+.. kernel-doc:: net/sched/sch_generic.c
+   :export:
+
+.. kernel-doc:: include/linux/etherdevice.h
+   :internal:
+
+.. kernel-doc:: include/linux/netdevice.h
+   :internal:
+
+.. kernel-doc:: include/net/net_shaper.h
+   :internal:
+
+PHY Support
+-----------
+
+.. kernel-doc:: drivers/net/phy/phy.c
+   :export:
+
+.. kernel-doc:: drivers/net/phy/phy.c
+   :internal:
+
+.. kernel-doc:: drivers/net/phy/phy-core.c
+   :export:
+
+.. kernel-doc:: drivers/net/phy/phy-c45.c
+   :export:
+
+.. kernel-doc:: include/linux/phy.h
+   :internal:
+
+.. kernel-doc:: drivers/net/phy/phy_device.c
+   :export:
+
+.. kernel-doc:: drivers/net/phy/phy_device.c
+   :internal:
+
+.. kernel-doc:: drivers/net/phy/mdio_bus.c
+   :export:
+
+.. kernel-doc:: drivers/net/phy/mdio_bus.c
+   :internal:
+
+PHYLINK
+-------
+
+  PHYLINK interfaces traditional network drivers with PHYLIB, fixed-links,
+  and SFF modules (eg, hot-pluggable SFP) that may contain PHYs.  PHYLINK
+  provides management of the link state and link modes.
+
+.. kernel-doc:: include/linux/phylink.h
+   :internal:
+
+.. kernel-doc:: drivers/net/phy/phylink.c
+
+SFP support
+-----------
+
+.. kernel-doc:: drivers/net/phy/sfp-bus.c
+   :internal:
+
+.. kernel-doc:: include/linux/sfp.h
+   :internal:
+
+.. kernel-doc:: drivers/net/phy/sfp-bus.c
+   :export: