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 --- samples/rust/rust_minimal.rs | 48 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 samples/rust/rust_minimal.rs (limited to 'samples/rust/rust_minimal.rs') diff --git a/samples/rust/rust_minimal.rs b/samples/rust/rust_minimal.rs new file mode 100644 index 000000000..8eb958357 --- /dev/null +++ b/samples/rust/rust_minimal.rs @@ -0,0 +1,48 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Rust minimal sample. + +use kernel::prelude::*; + +module! { + type: RustMinimal, + name: "rust_minimal", + authors: ["Rust for Linux Contributors"], + description: "Rust minimal sample", + license: "GPL", + params: { + test_parameter: i64 { + default: 1, + description: "This parameter has a default of 1", + }, + }, +} + +struct RustMinimal { + numbers: KVec, +} + +impl kernel::Module for RustMinimal { + fn init(_module: &'static ThisModule) -> Result { + pr_info!("Rust minimal sample (init)\n"); + pr_info!("Am I built-in? {}\n", !cfg!(MODULE)); + pr_info!( + "test_parameter: {}\n", + *module_parameters::test_parameter.value() + ); + + let mut numbers = KVec::new(); + numbers.push(72, GFP_KERNEL)?; + numbers.push(108, GFP_KERNEL)?; + numbers.push(200, GFP_KERNEL)?; + + Ok(RustMinimal { numbers }) + } +} + +impl Drop for RustMinimal { + fn drop(&mut self) { + pr_info!("My numbers are {:?}\n", self.numbers); + pr_info!("Rust minimal sample (exit)\n"); + } +} -- cgit v1.3.1