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/kunit/string-stream.h | 62 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 lib/kunit/string-stream.h (limited to 'lib/kunit/string-stream.h') diff --git a/lib/kunit/string-stream.h b/lib/kunit/string-stream.h new file mode 100644 index 000000000..7be2450c7 --- /dev/null +++ b/lib/kunit/string-stream.h @@ -0,0 +1,62 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * C++ stream style string builder used in KUnit for building messages. + * + * Copyright (C) 2019, Google LLC. + * Author: Brendan Higgins + */ + +#ifndef _KUNIT_STRING_STREAM_H +#define _KUNIT_STRING_STREAM_H + +#include +#include +#include + +struct string_stream_fragment { + struct list_head node; + char *fragment; +}; + +struct string_stream { + size_t length; + struct list_head fragments; + /* length and fragments are protected by this lock */ + spinlock_t lock; + gfp_t gfp; + bool append_newlines; +}; + +struct kunit; + +struct string_stream *kunit_alloc_string_stream(struct kunit *test, gfp_t gfp); +void kunit_free_string_stream(struct kunit *test, struct string_stream *stream); + +struct string_stream *alloc_string_stream(gfp_t gfp); +void free_string_stream(struct string_stream *stream); + +int __printf(2, 3) string_stream_add(struct string_stream *stream, + const char *fmt, ...); + +int __printf(2, 0) string_stream_vadd(struct string_stream *stream, + const char *fmt, + va_list args); + +void string_stream_clear(struct string_stream *stream); + +char *string_stream_get_string(struct string_stream *stream); + +int string_stream_append(struct string_stream *stream, + struct string_stream *other); + +bool string_stream_is_empty(struct string_stream *stream); + +void string_stream_destroy(struct string_stream *stream); + +static inline void string_stream_set_append_newlines(struct string_stream *stream, + bool append_newlines) +{ + stream->append_newlines = append_newlines; +} + +#endif /* _KUNIT_STRING_STREAM_H */ -- cgit v1.3.1