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/macros/export.rs | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 rust/macros/export.rs (limited to 'rust/macros/export.rs') diff --git a/rust/macros/export.rs b/rust/macros/export.rs new file mode 100644 index 000000000..6d53521f6 --- /dev/null +++ b/rust/macros/export.rs @@ -0,0 +1,25 @@ +// SPDX-License-Identifier: GPL-2.0 + +use proc_macro2::TokenStream; +use quote::quote; + +/// Please see [`crate::export`] for documentation. +pub(crate) fn export(f: syn::ItemFn) -> TokenStream { + let name = &f.sig.ident; + + quote! { + // This verifies that the function has the same signature as the declaration generated by + // bindgen. It makes use of the fact that all branches of an if/else must have the same + // type. + const _: () = { + if true { + ::kernel::bindings::#name + } else { + #name + }; + }; + + #[no_mangle] + #f + } +} -- cgit v1.3.1