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/net/arcnet/com9026.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) create mode 100644 drivers/net/arcnet/com9026.h (limited to 'drivers/net/arcnet/com9026.h') diff --git a/drivers/net/arcnet/com9026.h b/drivers/net/arcnet/com9026.h new file mode 100644 index 000000000..6adbc1871 --- /dev/null +++ b/drivers/net/arcnet/com9026.h @@ -0,0 +1,18 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __COM9026_H +#define __COM9026_H + +/* COM 9026 controller chip --> ARCnet register addresses */ + +#define COM9026_REG_W_INTMASK 0 /* writable */ +#define COM9026_REG_R_STATUS 0 /* readable */ +#define COM9026_REG_W_COMMAND 1 /* writable, returns random vals on read (?) */ +#define COM9026_REG_RW_CONFIG 2 /* Configuration register */ +#define COM9026_REG_R_RESET 8 /* software reset (on read) */ +#define COM9026_REG_RW_MEMDATA 12 /* Data port for IO-mapped memory */ +#define COM9026_REG_W_ADDR_LO 14 /* Control registers for said */ +#define COM9026_REG_W_ADDR_HI 15 + +#define COM9026_REG_R_STATION 1 /* Station ID */ + +#endif -- cgit v1.3.1