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 --- io_uring/opdef.h | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 io_uring/opdef.h (limited to 'io_uring/opdef.h') diff --git a/io_uring/opdef.h b/io_uring/opdef.h new file mode 100644 index 000000000..667f981e6 --- /dev/null +++ b/io_uring/opdef.h @@ -0,0 +1,58 @@ +// SPDX-License-Identifier: GPL-2.0 +#ifndef IOU_OP_DEF_H +#define IOU_OP_DEF_H + +struct io_uring_bpf_ctx; + +struct io_issue_def { + /* needs req->file assigned */ + unsigned needs_file : 1; + /* should block plug */ + unsigned plug : 1; + /* supports ioprio */ + unsigned ioprio : 1; + /* supports iopoll */ + unsigned iopoll : 1; + /* op supports buffer selection */ + unsigned buffer_select : 1; + /* hash wq insertion if file is a regular file */ + unsigned hash_reg_file : 1; + /* unbound wq insertion if file is a non-regular file */ + unsigned unbound_nonreg_file : 1; + /* set if opcode supports polled "wait" */ + unsigned pollin : 1; + unsigned pollout : 1; + unsigned poll_exclusive : 1; + /* skip auditing */ + unsigned audit_skip : 1; + /* vectored opcode, set if 1) vectored, and 2) handler needs to know */ + unsigned vectored : 1; + /* set to 1 if this opcode uses 128b sqes in a mixed sq */ + unsigned is_128 : 1; + + /* size of async data needed, if any */ + unsigned short async_size; + + /* bpf filter pdu size, if any */ + unsigned short filter_pdu_size; + + int (*issue)(struct io_kiocb *, unsigned int); + int (*prep)(struct io_kiocb *, const struct io_uring_sqe *); + void (*filter_populate)(struct io_uring_bpf_ctx *, struct io_kiocb *); +}; + +struct io_cold_def { + const char *name; + + void (*sqe_copy)(struct io_kiocb *); + void (*cleanup)(struct io_kiocb *); + void (*fail)(struct io_kiocb *); +}; + +extern const struct io_issue_def io_issue_defs[]; +extern const struct io_cold_def io_cold_defs[]; + +bool io_uring_op_supported(u8 opcode); + +void io_uring_optable_init(void); +#endif -- cgit v1.3.1