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/uring_cmd.h | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 io_uring/uring_cmd.h (limited to 'io_uring/uring_cmd.h') diff --git a/io_uring/uring_cmd.h b/io_uring/uring_cmd.h new file mode 100644 index 000000000..041aef8a8 --- /dev/null +++ b/io_uring/uring_cmd.h @@ -0,0 +1,26 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include + +struct io_async_cmd { + struct iou_vec vec; + struct io_uring_sqe sqes[2]; +}; + +int io_uring_cmd(struct io_kiocb *req, unsigned int issue_flags); +int io_uring_cmd_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); +void io_uring_cmd_sqe_copy(struct io_kiocb *req); +void io_uring_cmd_cleanup(struct io_kiocb *req); + +bool io_uring_try_cancel_uring_cmd(struct io_ring_ctx *ctx, + struct io_uring_task *tctx, bool cancel_all); + +bool io_uring_cmd_post_mshot_cqe32(struct io_uring_cmd *cmd, + unsigned int issue_flags, + struct io_uring_cqe cqe[2]); + +void io_cmd_cache_free(const void *entry); + +int io_cmd_poll_multishot(struct io_uring_cmd *cmd, + unsigned int issue_flags, __poll_t mask); -- cgit v1.3.1