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 --- drivers/video/fbdev/pm2fb.c | 1855 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1855 insertions(+) create mode 100644 drivers/video/fbdev/pm2fb.c (limited to 'drivers/video/fbdev/pm2fb.c') diff --git a/drivers/video/fbdev/pm2fb.c b/drivers/video/fbdev/pm2fb.c new file mode 100644 index 000000000..058075a34 --- /dev/null +++ b/drivers/video/fbdev/pm2fb.c @@ -0,0 +1,1855 @@ +/* + * Permedia2 framebuffer driver. + * + * 2.5/2.6 driver: + * Copyright (c) 2003 Jim Hague (jim.hague@acm.org) + * + * based on 2.4 driver: + * Copyright (c) 1998-2000 Ilario Nardinocchi (nardinoc@CS.UniBO.IT) + * Copyright (c) 1999 Jakub Jelinek (jakub@redhat.com) + * + * and additional input from James Simmon's port of Hannu Mallat's tdfx + * driver. + * + * I have a Creative Graphics Blaster Exxtreme card - pm2fb on x86. I + * have no access to other pm2fb implementations. Sparc (and thus + * hopefully other big-endian) devices now work, thanks to a lot of + * testing work by Ron Murray. I have no access to CVision hardware, + * and therefore for now I am omitting the CVision code. + * + * Multiple boards support has been on the TODO list for ages. + * Don't expect this to change. + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file COPYING in the main directory of this archive for + * more details. + * + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include