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 --- lib/raid/raid6/algos.h | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 lib/raid/raid6/algos.h (limited to 'lib/raid/raid6/algos.h') diff --git a/lib/raid/raid6/algos.h b/lib/raid/raid6/algos.h new file mode 100644 index 000000000..43f636be1 --- /dev/null +++ b/lib/raid/raid6/algos.h @@ -0,0 +1,41 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright 2003 H. Peter Anvin - All Rights Reserved + */ +#ifndef _PQ_IMPL_H +#define _PQ_IMPL_H + +#include +#include + +/* Routine choices */ +struct raid6_calls { + const char *name; + void (*gen_syndrome)(int disks, size_t bytes, void **ptrs); + void (*xor_syndrome)(int disks, int start, int stop, size_t bytes, + void **ptrs); +}; + +struct raid6_recov_calls { + const char *name; + void (*data2)(int disks, size_t bytes, int faila, int failb, + void **ptrs); + void (*datap)(int disks, size_t bytes, int faila, void **ptrs); +}; + +void __init raid6_algo_add(const struct raid6_calls *algo); +void __init raid6_algo_add_default(void); +void __init raid6_recov_algo_add(const struct raid6_recov_calls *algo); + +/* for the kunit test */ +const struct raid6_calls *raid6_algo_find(unsigned int idx); +const struct raid6_recov_calls *raid6_recov_algo_find(unsigned int idx); + +/* generic implementations */ +extern const struct raid6_calls raid6_intx1; +extern const struct raid6_calls raid6_intx2; +extern const struct raid6_calls raid6_intx4; +extern const struct raid6_calls raid6_intx8; +extern const struct raid6_recov_calls raid6_recov_intx1; + +#endif /* _PQ_IMPL_H */ -- cgit v1.3.1