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/syn/print.rs | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) create mode 100644 rust/syn/print.rs (limited to 'rust/syn/print.rs') diff --git a/rust/syn/print.rs b/rust/syn/print.rs new file mode 100644 index 000000000..d73262cda --- /dev/null +++ b/rust/syn/print.rs @@ -0,0 +1,18 @@ +// SPDX-License-Identifier: Apache-2.0 OR MIT + +use proc_macro2::TokenStream; +use quote::ToTokens; + +pub(crate) struct TokensOrDefault<'a, T: 'a>(pub &'a Option); + +impl<'a, T> ToTokens for TokensOrDefault<'a, T> +where + T: ToTokens + Default, +{ + fn to_tokens(&self, tokens: &mut TokenStream) { + match self.0 { + Some(t) => t.to_tokens(tokens), + None => T::default().to_tokens(tokens), + } + } +} -- cgit v1.3.1