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/firewire/nosy-user.h | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 drivers/firewire/nosy-user.h (limited to 'drivers/firewire/nosy-user.h') diff --git a/drivers/firewire/nosy-user.h b/drivers/firewire/nosy-user.h new file mode 100644 index 000000000..3446c5b77 --- /dev/null +++ b/drivers/firewire/nosy-user.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __nosy_user_h +#define __nosy_user_h + +#include +#include + +#define NOSY_IOC_GET_STATS _IOR('&', 0, struct nosy_stats) +#define NOSY_IOC_START _IO('&', 1) +#define NOSY_IOC_STOP _IO('&', 2) +#define NOSY_IOC_FILTER _IOW('&', 2, __u32) + +struct nosy_stats { + __u32 total_packet_count; + __u32 lost_packet_count; +}; + +/* + * Format of packets returned from the kernel driver: + * + * quadlet with timestamp (microseconds, CPU endian) + * quadlet-padded packet data... (little endian) + * quadlet with ack (little endian) + */ + +#endif /* __nosy_user_h */ -- cgit v1.3.1