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/pds.h | 62 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 include/uapi/fwctl/pds.h (limited to 'include/uapi/fwctl/pds.h') diff --git a/include/uapi/fwctl/pds.h b/include/uapi/fwctl/pds.h new file mode 100644 index 000000000..66be32411 --- /dev/null +++ b/include/uapi/fwctl/pds.h @@ -0,0 +1,62 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* Copyright(c) Advanced Micro Devices, Inc */ + +/* + * fwctl interface info for pds_fwctl + */ + +#ifndef _UAPI_FWCTL_PDS_H_ +#define _UAPI_FWCTL_PDS_H_ + +#include + +/** + * struct fwctl_info_pds + * @uctx_caps: bitmap of firmware capabilities + * + * Return basic information about the FW interface available. + */ +struct fwctl_info_pds { + __u32 uctx_caps; +}; + +/** + * enum pds_fwctl_capabilities + * @PDS_FWCTL_QUERY_CAP: firmware can be queried for information + * @PDS_FWCTL_SEND_CAP: firmware can be sent commands + */ +enum pds_fwctl_capabilities { + PDS_FWCTL_QUERY_CAP = 0, + PDS_FWCTL_SEND_CAP, +}; + +/** + * struct fwctl_rpc_pds + * @in.op: requested operation code + * @in.ep: firmware endpoint to operate on + * @in.rsvd: reserved + * @in.len: length of payload data + * @in.payload: address of payload buffer + * @in: rpc in parameters + * @out.retval: operation result value + * @out.rsvd: reserved + * @out.len: length of result data buffer + * @out.payload: address of payload data buffer + * @out: rpc out parameters + */ +struct fwctl_rpc_pds { + struct { + __u32 op; + __u32 ep; + __u32 rsvd; + __u32 len; + __aligned_u64 payload; + } in; + struct { + __u32 retval; + __u32 rsvd[2]; + __u32 len; + __aligned_u64 payload; + } out; +}; +#endif /* _UAPI_FWCTL_PDS_H_ */ -- cgit v1.3.1