From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall 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 Signed-off-by: Stafford Horne --- .../admin-guide/media/raspberrypi-pisp-be.dot | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) create mode 100644 Documentation/admin-guide/media/raspberrypi-pisp-be.dot (limited to 'Documentation/admin-guide/media/raspberrypi-pisp-be.dot') diff --git a/Documentation/admin-guide/media/raspberrypi-pisp-be.dot b/Documentation/admin-guide/media/raspberrypi-pisp-be.dot new file mode 100644 index 000000000..55671dc1d --- /dev/null +++ b/Documentation/admin-guide/media/raspberrypi-pisp-be.dot @@ -0,0 +1,20 @@ +digraph board { + rankdir=TB + n00000001 [label="{{ 0 | 1 | 2 | 7} | pispbe\n | { 3 | 4 | 5 | 6}}", shape=Mrecord, style=filled, fillcolor=green] + n00000001:port3 -> n0000001c [style=bold] + n00000001:port4 -> n00000022 [style=bold] + n00000001:port5 -> n00000028 [style=bold] + n00000001:port6 -> n0000002e [style=bold] + n0000000a [label="pispbe-input\n/dev/video0", shape=box, style=filled, fillcolor=yellow] + n0000000a -> n00000001:port0 [style=bold] + n00000010 [label="pispbe-tdn_input\n/dev/video1", shape=box, style=filled, fillcolor=yellow] + n00000010 -> n00000001:port1 [style=bold] + n00000016 [label="pispbe-stitch_input\n/dev/video2", shape=box, style=filled, fillcolor=yellow] + n00000016 -> n00000001:port2 [style=bold] + n0000001c [label="pispbe-output0\n/dev/video3", shape=box, style=filled, fillcolor=yellow] + n00000022 [label="pispbe-output1\n/dev/video4", shape=box, style=filled, fillcolor=yellow] + n00000028 [label="pispbe-tdn_output\n/dev/video5", shape=box, style=filled, fillcolor=yellow] + n0000002e [label="pispbe-stitch_output\n/dev/video6", shape=box, style=filled, fillcolor=yellow] + n00000034 [label="pispbe-config\n/dev/video7", shape=box, style=filled, fillcolor=yellow] + n00000034 -> n00000001:port7 [style=bold] +} -- cgit v1.3.1