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/pxafb.c | 2440 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 2440 insertions(+) create mode 100644 drivers/video/fbdev/pxafb.c (limited to 'drivers/video/fbdev/pxafb.c') diff --git a/drivers/video/fbdev/pxafb.c b/drivers/video/fbdev/pxafb.c new file mode 100644 index 000000000..e418eee82 --- /dev/null +++ b/drivers/video/fbdev/pxafb.c @@ -0,0 +1,2440 @@ +/* + * linux/drivers/video/pxafb.c + * + * Copyright (C) 1999 Eric A. Thomas. + * Copyright (C) 2004 Jean-Frederic Clere. + * Copyright (C) 2004 Ian Campbell. + * Copyright (C) 2004 Jeff Lackey. + * Based on sa1100fb.c Copyright (C) 1999 Eric A. Thomas + * which in turn is + * Based on acornfb.c Copyright (C) Russell King. + * + * 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. + * + * Intel PXA250/210 LCD Controller Frame Buffer Driver + * + * Please direct your questions and comments on this driver to the following + * email address: + * + * linux-arm-kernel@lists.arm.linux.org.uk + * + * Add support for overlay1 and overlay2 based on pxafb_overlay.c: + * + * Copyright (C) 2004, Intel Corporation + * + * 2003/08/27: + * 2004/03/10: + * 2004/10/28: + * + * Copyright (C) 2006-2008 Marvell International Ltd. + * All Rights Reserved + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include