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/char/nwbutton.h | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 drivers/char/nwbutton.h (limited to 'drivers/char/nwbutton.h') diff --git a/drivers/char/nwbutton.h b/drivers/char/nwbutton.h new file mode 100644 index 000000000..f2b9fdc1f --- /dev/null +++ b/drivers/char/nwbutton.h @@ -0,0 +1,40 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __NWBUTTON_H +#define __NWBUTTON_H + +/* + * NetWinder Button Driver- + * Copyright (C) Alex Holden 1998, 1999. + */ + +#ifdef __NWBUTTON_C /* Actually compiling the driver itself */ + +/* Various defines: */ + +#define NUM_PRESSES_REBOOT 2 /* How many presses to activate shutdown */ +#define BUTTON_DELAY 30 /* How many jiffies for sequence to end */ +#define VERSION "0.3" /* Driver version number */ + +/* Structure definitions: */ + +struct button_callback { + void (*callback) (void); + int count; +}; + +/* Function prototypes: */ + +static void button_sequence_finished(struct timer_list *unused); +static irqreturn_t button_handler (int irq, void *dev_id); +int button_init (void); +int button_add_callback (void (*callback) (void), int count); +int button_del_callback (void (*callback) (void)); +static void button_consume_callbacks (int bpcount); + +#else /* Not compiling the driver itself */ + +extern int button_add_callback (void (*callback) (void), int count); +extern int button_del_callback (void (*callback) (void)); + +#endif /* __NWBUTTON_C */ +#endif /* __NWBUTTON_H */ -- cgit v1.3.1