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/neofb.c | 2218 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 2218 insertions(+) create mode 100644 drivers/video/fbdev/neofb.c (limited to 'drivers/video/fbdev/neofb.c') diff --git a/drivers/video/fbdev/neofb.c b/drivers/video/fbdev/neofb.c new file mode 100644 index 000000000..e0b8d4d6c --- /dev/null +++ b/drivers/video/fbdev/neofb.c @@ -0,0 +1,2218 @@ +/* + * linux/drivers/video/neofb.c -- NeoMagic Framebuffer Driver + * + * Copyright (c) 2001-2002 Denis Oliver Kropp + * + * + * Card specific code is based on XFree86's neomagic driver. + * Framebuffer framework code is based on code of cyber2000fb. + * + * 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. + * + * + * 0.4.1 + * - Cosmetic changes (dok) + * + * 0.4 + * - Toshiba Libretto support, allow modes larger than LCD size if + * LCD is disabled, keep BIOS settings if internal/external display + * haven't been enabled explicitly + * (Thomas J. Moore ) + * + * 0.3.3 + * - Porting over to new fbdev api. (jsimmons) + * + * 0.3.2 + * - got rid of all floating point (dok) + * + * 0.3.1 + * - added module license (dok) + * + * 0.3 + * - hardware accelerated clear and move for 2200 and above (dok) + * - maximum allowed dotclock is handled now (dok) + * + * 0.2.1 + * - correct panning after X usage (dok) + * - added module and kernel parameters (dok) + * - no stretching if external display is enabled (dok) + * + * 0.2 + * - initial version (dok) + * + * + * TODO + * - ioctl for internal/external switching + * - blanking + * - 32bit depth support, maybe impossible + * - disable pan-on-sync, need specs + * + * BUGS + * - white margin on bootup like with tdfxfb (colormap problem?) + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#ifdef CONFIG_TOSHIBA +#include +#endif + +#include +#include +#include