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 --- rust/uapi/lib.rs | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 rust/uapi/lib.rs (limited to 'rust/uapi/lib.rs') diff --git a/rust/uapi/lib.rs b/rust/uapi/lib.rs new file mode 100644 index 000000000..797ead5b5 --- /dev/null +++ b/rust/uapi/lib.rs @@ -0,0 +1,40 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! UAPI Bindings. +//! +//! Contains the bindings generated by `bindgen` for UAPI interfaces. +//! +//! This crate may be used directly by drivers that need to interact with +//! userspace APIs. + +#![no_std] +#![allow( + clippy::all, + clippy::cast_lossless, + clippy::ptr_as_ptr, + clippy::ref_as_ptr, + clippy::undocumented_unsafe_blocks, + dead_code, + missing_docs, + non_camel_case_types, + non_upper_case_globals, + non_snake_case, + improper_ctypes, + unreachable_pub, + unsafe_op_in_unsafe_fn +)] +#![cfg_attr(CONFIG_RUSTC_HAS_UNNECESSARY_TRANSMUTES, allow(unnecessary_transmutes))] +#![cfg_attr( + CONFIG_RUSTC_HAS_SUSPICIOUS_RUNTIME_SYMBOL_DEFINITIONS, + allow(suspicious_runtime_symbol_definitions) +)] +#![feature(cfi_encoding)] + +// Manual definition of blocklisted types. +type __kernel_size_t = usize; +type __kernel_ssize_t = isize; +type __kernel_ptrdiff_t = isize; + +use pin_init::MaybeZeroable; + +include!(concat!(env!("OBJTREE"), "/rust/uapi/uapi_generated.rs")); -- cgit v1.3.1