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/btf.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) create mode 100644 tools/perf/util/btf.c (limited to 'tools/perf/util/btf.c') diff --git a/tools/perf/util/btf.c b/tools/perf/util/btf.c new file mode 100644 index 000000000..50d98f3e8 --- /dev/null +++ b/tools/perf/util/btf.c @@ -0,0 +1,27 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Arnaldo Carvalho de Melo + * + * Copyright (C) 2024, Red Hat, Inc + */ + +#include +#include +#include + +const struct btf_member *__btf_type__find_member_by_name(struct btf *btf, + int type_id, const char *member_name) +{ + const struct btf_type *t = btf__type_by_id(btf, type_id); + const struct btf_member *m; + u32 i; + + for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) { + const char *current_member_name = btf__name_by_offset(btf, m->name_off); + + if (!strcmp(current_member_name, member_name)) + return m; + } + + return NULL; +} -- cgit v1.3.1