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/uapi/fwctl/cxl.h | 56 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 include/uapi/fwctl/cxl.h (limited to 'include/uapi/fwctl/cxl.h') diff --git a/include/uapi/fwctl/cxl.h b/include/uapi/fwctl/cxl.h new file mode 100644 index 000000000..43f522f0c --- /dev/null +++ b/include/uapi/fwctl/cxl.h @@ -0,0 +1,56 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Copyright (c) 2024-2025 Intel Corporation + * + * These are definitions for the mailbox command interface of CXL subsystem. + */ +#ifndef _UAPI_FWCTL_CXL_H_ +#define _UAPI_FWCTL_CXL_H_ + +#include +#include +#include + +/** + * struct fwctl_rpc_cxl - ioctl(FWCTL_RPC) input for CXL + * @opcode: CXL mailbox command opcode + * @flags: Flags for the command (input). + * @op_size: Size of input payload. + * @reserved1: Reserved. Must be 0s. + * @get_sup_feats_in: Get Supported Features input + * @get_feat_in: Get Feature input + * @set_feat_in: Set Feature input + */ +struct fwctl_rpc_cxl { + __struct_group(fwctl_rpc_cxl_hdr, hdr, /* no attrs */, + __u32 opcode; + __u32 flags; + __u32 op_size; + __u32 reserved1; + ); + union { + struct cxl_mbox_get_sup_feats_in get_sup_feats_in; + struct cxl_mbox_get_feat_in get_feat_in; + struct cxl_mbox_set_feat_in set_feat_in; + }; +}; + +/** + * struct fwctl_rpc_cxl_out - ioctl(FWCTL_RPC) output for CXL + * @size: Size of the output payload + * @retval: Return value from device + * @get_sup_feats_out: Get Supported Features output + * @payload: raw byte stream of payload + */ +struct fwctl_rpc_cxl_out { + __struct_group(fwctl_rpc_cxl_out_hdr, hdr, /* no attrs */, + __u32 size; + __u32 retval; + ); + union { + struct cxl_mbox_get_sup_feats_out get_sup_feats_out; + __DECLARE_FLEX_ARRAY(__u8, payload); + }; +}; + +#endif -- cgit v1.3.1