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/helpers/err.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) create mode 100644 rust/helpers/err.c (limited to 'rust/helpers/err.c') diff --git a/rust/helpers/err.c b/rust/helpers/err.c new file mode 100644 index 000000000..2872158e3 --- /dev/null +++ b/rust/helpers/err.c @@ -0,0 +1,18 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +__rust_helper __force void *rust_helper_ERR_PTR(long err) +{ + return ERR_PTR(err); +} + +__rust_helper bool rust_helper_IS_ERR(__force const void *ptr) +{ + return IS_ERR(ptr); +} + +__rust_helper long rust_helper_PTR_ERR(__force const void *ptr) +{ + return PTR_ERR(ptr); +} -- cgit v1.3.1