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/openclose.h | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) create mode 100644 io_uring/openclose.h (limited to 'io_uring/openclose.h') diff --git a/io_uring/openclose.h b/io_uring/openclose.h new file mode 100644 index 000000000..566739920 --- /dev/null +++ b/io_uring/openclose.h @@ -0,0 +1,23 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "bpf_filter.h" + +int __io_close_fixed(struct io_ring_ctx *ctx, unsigned int issue_flags, + unsigned int offset); + +int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); +int io_openat(struct io_kiocb *req, unsigned int issue_flags); +void io_open_cleanup(struct io_kiocb *req); +void io_openat_bpf_populate(struct io_uring_bpf_ctx *bctx, struct io_kiocb *req); + +int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); +int io_openat2(struct io_kiocb *req, unsigned int issue_flags); + +int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); +int io_close(struct io_kiocb *req, unsigned int issue_flags); + +int io_pipe_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); +int io_pipe(struct io_kiocb *req, unsigned int issue_flags); + +int io_install_fixed_fd_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); +int io_install_fixed_fd(struct io_kiocb *req, unsigned int issue_flags); -- cgit v1.3.1