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/tests/thread-maps-share.c | 100 +++++++++++++++++++++++++++++++++++ 1 file changed, 100 insertions(+) create mode 100644 tools/perf/tests/thread-maps-share.c (limited to 'tools/perf/tests/thread-maps-share.c') diff --git a/tools/perf/tests/thread-maps-share.c b/tools/perf/tests/thread-maps-share.c new file mode 100644 index 000000000..0431bff31 --- /dev/null +++ b/tools/perf/tests/thread-maps-share.c @@ -0,0 +1,100 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "tests.h" +#include "machine.h" +#include "thread.h" +#include "debug.h" + +static int test__thread_maps_share(struct test_suite *test __maybe_unused, int subtest __maybe_unused) +{ + struct machines machines; + struct machine *machine; + + /* thread group */ + struct thread *leader; + struct thread *t1, *t2, *t3; + struct maps *maps; + + /* other process */ + struct thread *other, *other_leader; + struct maps *other_maps; + + /* + * This test create 2 processes abstractions (struct thread) + * with several threads and checks they properly share and + * maintain maps info (struct maps). + * + * thread group (pid: 0, tids: 0, 1, 2, 3) + * other group (pid: 4, tids: 4, 5) + */ + + TEST_ASSERT_VAL("failed to init machines", machines__init(&machines) == 0); + machine = &machines.host; + + /* create process with 4 threads */ + leader = machine__findnew_thread(machine, 0, 0); + t1 = machine__findnew_thread(machine, 0, 1); + t2 = machine__findnew_thread(machine, 0, 2); + t3 = machine__findnew_thread(machine, 0, 3); + + /* and create 1 separated process, without thread leader */ + other = machine__findnew_thread(machine, 4, 5); + + TEST_ASSERT_VAL("failed to create threads", + leader && t1 && t2 && t3 && other); + + maps = thread__maps(leader); + TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(maps__refcnt(maps)), 4); + + /* test the maps pointer is shared */ + TEST_ASSERT_VAL("maps don't match", maps__equal(maps, thread__maps(t1))); + TEST_ASSERT_VAL("maps don't match", maps__equal(maps, thread__maps(t2))); + TEST_ASSERT_VAL("maps don't match", maps__equal(maps, thread__maps(t3))); + + /* + * Verify the other leader was created by previous call. + * It should have shared maps with no change in + * refcnt. + */ + other_leader = machine__find_thread(machine, 4, 4); + TEST_ASSERT_VAL("failed to find other leader", other_leader); + + /* + * Ok, now that all the rbtree related operations were done, + * lets remove all of them from there so that we can do the + * refcounting tests. + */ + machine__remove_thread(machine, leader); + machine__remove_thread(machine, t1); + machine__remove_thread(machine, t2); + machine__remove_thread(machine, t3); + machine__remove_thread(machine, other); + machine__remove_thread(machine, other_leader); + + other_maps = thread__maps(other); + TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(maps__refcnt(other_maps)), 2); + + TEST_ASSERT_VAL("maps don't match", maps__equal(other_maps, thread__maps(other_leader))); + + /* release thread group */ + thread__put(t3); + TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(maps__refcnt(maps)), 3); + + thread__put(t2); + TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(maps__refcnt(maps)), 2); + + thread__put(t1); + TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(maps__refcnt(maps)), 1); + + thread__put(leader); + + /* release other group */ + thread__put(other_leader); + TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(maps__refcnt(other_maps)), 1); + + thread__put(other); + + machines__exit(&machines); + return 0; +} + +DEFINE_SUITE("Share thread maps", thread_maps_share); -- cgit v1.3.1