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, 121 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-class-net-queues b/Documentation/ABI/testing/sysfs-class-net-queues
new file mode 100644
index 000000000..84aa25e0d
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-net-queues
@@ -0,0 +1,121 @@
+What:		/sys/class/net/<iface>/queues/rx-<queue>/rps_cpus
+Date:		March 2010
+KernelVersion:	2.6.35
+Contact:	netdev@vger.kernel.org
+Description:
+		Mask of the CPU(s) currently enabled to participate into the
+		Receive Packet Steering packet processing flow for this
+		network device queue. Possible values depend on the number
+		of available CPU(s) in the system.
+
+What:		/sys/class/net/<iface>/queues/rx-<queue>/rps_flow_cnt
+Date:		April 2010
+KernelVersion:	2.6.35
+Contact:	netdev@vger.kernel.org
+Description:
+		Number of Receive Packet Steering flows being currently
+		processed by this particular network device receive queue.
+
+What:		/sys/class/net/<iface>/queues/tx-<queue>/tx_timeout
+Date:		November 2011
+KernelVersion:	3.3
+Contact:	netdev@vger.kernel.org
+Description:
+		Indicates the number of transmit timeout events seen by this
+		network interface transmit queue.
+
+What:		/sys/class/net/<iface>/queues/tx-<queue>/tx_maxrate
+Date:		March 2015
+KernelVersion:	4.1
+Contact:	netdev@vger.kernel.org
+Description:
+		A Mbps max-rate set for the queue, a value of zero means disabled,
+		default is disabled.
+
+What:		/sys/class/net/<iface>/queues/tx-<queue>/xps_cpus
+Date:		November 2010
+KernelVersion:	2.6.38
+Contact:	netdev@vger.kernel.org
+Description:
+		Mask of the CPU(s) currently enabled to participate into the
+		Transmit Packet Steering packet processing flow for this
+		network device transmit queue. Possible values depend on the
+		number of available CPU(s) in the system.
+
+What:		/sys/class/net/<iface>/queues/tx-<queue>/xps_rxqs
+Date:		June 2018
+KernelVersion:	4.18.0
+Contact:	netdev@vger.kernel.org
+Description:
+		Mask of the receive queue(s) currently enabled to participate
+		into the Transmit Packet Steering packet processing flow for this
+		network device transmit queue. Possible values depend on the
+		number of available receive queue(s) in the network device.
+		Default is disabled.
+
+What:		/sys/class/net/<iface>/queues/tx-<queue>/byte_queue_limits/hold_time
+Date:		November 2011
+KernelVersion:	3.3
+Contact:	netdev@vger.kernel.org
+Description:
+		Indicates the hold time in milliseconds to measure the slack
+		of this particular network device transmit queue.
+		Default value is 1000.
+
+What:		/sys/class/net/<iface>/queues/tx-<queue>/byte_queue_limits/inflight
+Date:		November 2011
+KernelVersion:	3.3
+Contact:	netdev@vger.kernel.org
+Description:
+		Indicates the number of bytes (objects) in flight on this
+		network device transmit queue.
+
+What:		/sys/class/net/<iface>/queues/tx-<queue>/byte_queue_limits/limit
+Date:		November 2011
+KernelVersion:	3.3
+Contact:	netdev@vger.kernel.org
+Description:
+		Indicates the current limit of bytes allowed to be queued
+		on this network device transmit queue. This value is clamped
+		to be within the bounds defined by limit_max and limit_min.
+
+What:		/sys/class/net/<iface>/queues/tx-<queue>/byte_queue_limits/limit_max
+Date:		November 2011
+KernelVersion:	3.3
+Contact:	netdev@vger.kernel.org
+Description:
+		Indicates the absolute maximum limit of bytes allowed to be
+		queued on this network device transmit queue. See
+		include/linux/dynamic_queue_limits.h for the default value.
+
+What:		/sys/class/net/<iface>/queues/tx-<queue>/byte_queue_limits/limit_min
+Date:		November 2011
+KernelVersion:	3.3
+Contact:	netdev@vger.kernel.org
+Description:
+		Indicates the absolute minimum limit of bytes allowed to be
+		queued on this network device transmit queue. Default value is
+		0.
+
+What:		/sys/class/net/<iface>/queues/tx-<queue>/byte_queue_limits/stall_thrs
+Date:		Jan 2024
+KernelVersion:	6.9
+Contact:	netdev@vger.kernel.org
+Description:
+		Tx completion stall detection threshold in ms. Kernel will
+		guarantee to detect all stalls longer than this threshold but
+		may also detect stalls longer than half of the threshold.
+
+What:		/sys/class/net/<iface>/queues/tx-<queue>/byte_queue_limits/stall_cnt
+Date:		Jan 2024
+KernelVersion:	6.9
+Contact:	netdev@vger.kernel.org
+Description:
+		Number of detected Tx completion stalls.
+
+What:		/sys/class/net/<iface>/queues/tx-<queue>/byte_queue_limits/stall_max
+Date:		Jan 2024
+KernelVersion:	6.9
+Contact:	netdev@vger.kernel.org
+Description:
+		Longest detected Tx completion stall. Write 0 to clear.