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/atafb.h | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 drivers/video/fbdev/atafb.h (limited to 'drivers/video/fbdev/atafb.h') diff --git a/drivers/video/fbdev/atafb.h b/drivers/video/fbdev/atafb.h new file mode 100644 index 000000000..2b2675980 --- /dev/null +++ b/drivers/video/fbdev/atafb.h @@ -0,0 +1,37 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _VIDEO_ATAFB_H +#define _VIDEO_ATAFB_H + +void atafb_mfb_copyarea(struct fb_info *info, u_long next_line, int sy, int sx, int dy, + int dx, int height, int width); +void atafb_mfb_fillrect(struct fb_info *info, u_long next_line, u32 color, + int sy, int sx, int height, int width); +void atafb_mfb_linefill(struct fb_info *info, u_long next_line, + int dy, int dx, u32 width, + const u8 *data, u32 bgcolor, u32 fgcolor); + +void atafb_iplan2p2_copyarea(struct fb_info *info, u_long next_line, int sy, int sx, int dy, + int dx, int height, int width); +void atafb_iplan2p2_fillrect(struct fb_info *info, u_long next_line, u32 color, + int sy, int sx, int height, int width); +void atafb_iplan2p2_linefill(struct fb_info *info, u_long next_line, + int dy, int dx, u32 width, + const u8 *data, u32 bgcolor, u32 fgcolor); + +void atafb_iplan2p4_copyarea(struct fb_info *info, u_long next_line, int sy, int sx, int dy, + int dx, int height, int width); +void atafb_iplan2p4_fillrect(struct fb_info *info, u_long next_line, u32 color, + int sy, int sx, int height, int width); +void atafb_iplan2p4_linefill(struct fb_info *info, u_long next_line, + int dy, int dx, u32 width, + const u8 *data, u32 bgcolor, u32 fgcolor); + +void atafb_iplan2p8_copyarea(struct fb_info *info, u_long next_line, int sy, int sx, int dy, + int dx, int height, int width); +void atafb_iplan2p8_fillrect(struct fb_info *info, u_long next_line, u32 color, + int sy, int sx, int height, int width); +void atafb_iplan2p8_linefill(struct fb_info *info, u_long next_line, + int dy, int dx, u32 width, + const u8 *data, u32 bgcolor, u32 fgcolor); + +#endif /* _VIDEO_ATAFB_H */ -- cgit v1.3.1