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 --- tools/perf/util/threads.h | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 tools/perf/util/threads.h (limited to 'tools/perf/util/threads.h') diff --git a/tools/perf/util/threads.h b/tools/perf/util/threads.h new file mode 100644 index 000000000..da68d2223 --- /dev/null +++ b/tools/perf/util/threads.h @@ -0,0 +1,35 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __PERF_THREADS_H +#define __PERF_THREADS_H + +#include "hashmap.h" +#include "rwsem.h" + +struct thread; + +#define THREADS__TABLE_BITS 3 +#define THREADS__TABLE_SIZE (1 << THREADS__TABLE_BITS) + +struct threads_table_entry { + /* Key is tid, value is struct thread. */ + struct hashmap shard; + struct rw_semaphore lock; + struct thread *last_match; +}; + +struct threads { + struct threads_table_entry table[THREADS__TABLE_SIZE]; +}; + +void threads__init(struct threads *threads); +void threads__exit(struct threads *threads); +size_t threads__nr(struct threads *threads); +struct thread *threads__find(struct threads *threads, pid_t tid); +struct thread *threads__findnew(struct threads *threads, pid_t pid, pid_t tid, bool *created); +void threads__remove_all_threads(struct threads *threads); +void threads__remove(struct threads *threads, struct thread *thread); +int threads__for_each_thread(struct threads *threads, + int (*fn)(struct thread *thread, void *data), + void *data); + +#endif /* __PERF_THREADS_H */ -- cgit v1.3.1