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 --- include/memory/renesas-rpc-if.h | 83 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) create mode 100644 include/memory/renesas-rpc-if.h (limited to 'include/memory') diff --git a/include/memory/renesas-rpc-if.h b/include/memory/renesas-rpc-if.h new file mode 100644 index 000000000..53663c4e5 --- /dev/null +++ b/include/memory/renesas-rpc-if.h @@ -0,0 +1,83 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Renesas RPC-IF core driver + * + * Copyright (C) 2018~2019 Renesas Solutions Corp. + * Copyright (C) 2019 Macronix International Co., Ltd. + * Copyright (C) 2019-2020 Cogent Embedded, Inc. + */ + +#ifndef __RENESAS_RPC_IF_H +#define __RENESAS_RPC_IF_H + +#include +#include + +enum rpcif_data_dir { + RPCIF_NO_DATA, + RPCIF_DATA_IN, + RPCIF_DATA_OUT, +}; + +struct rpcif_op { + struct { + u8 buswidth; + u8 opcode; + bool ddr; + } cmd, ocmd; + + struct { + u8 nbytes; + u8 buswidth; + bool ddr; + u64 val; + } addr; + + struct { + u8 ncycles; + u8 buswidth; + } dummy; + + struct { + u8 nbytes; + u8 buswidth; + bool ddr; + u32 val; + } option; + + struct { + u8 buswidth; + unsigned int nbytes; + enum rpcif_data_dir dir; + bool ddr; + union { + void *in; + const void *out; + } buf; + } data; +}; + +enum rpcif_type { + RPCIF_RCAR_GEN3, + RPCIF_RCAR_GEN4, + RPCIF_RZ_G2L, + XSPI_RZ_G3E, +}; + +struct rpcif { + struct device *dev; + void __iomem *dirmap; + size_t size; + bool xspi; +}; + +int rpcif_sw_init(struct rpcif *rpc, struct device *dev); +int rpcif_hw_init(struct device *dev, bool hyperflash); +void rpcif_prepare(struct device *dev, const struct rpcif_op *op, u64 *offs, + size_t *len); +int rpcif_manual_xfer(struct device *dev); +ssize_t rpcif_dirmap_read(struct device *dev, u64 offs, size_t len, void *buf); +ssize_t xspi_dirmap_write(struct device *dev, u64 offs, size_t len, + const void *buf); + +#endif // __RENESAS_RPC_IF_H -- cgit v1.3.1