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/task-exit.c | 161 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 161 insertions(+) create mode 100644 tools/perf/tests/task-exit.c (limited to 'tools/perf/tests/task-exit.c') diff --git a/tools/perf/tests/task-exit.c b/tools/perf/tests/task-exit.c new file mode 100644 index 000000000..4053ff281 --- /dev/null +++ b/tools/perf/tests/task-exit.c @@ -0,0 +1,161 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "debug.h" +#include "evlist.h" +#include "evsel.h" +#include "target.h" +#include "thread_map.h" +#include "tests.h" +#include "util/mmap.h" + +#include +#include +#include +#include +#include +#include + +static int exited; +static int nr_exit; + +static void sig_handler(int sig __maybe_unused) +{ + exited = 1; +} + +/* + * evlist__prepare_workload will send a SIGUSR1 if the fork fails, since + * we asked by setting its exec_error to this handler. + */ +static void workload_exec_failed_signal(int signo __maybe_unused, + siginfo_t *info __maybe_unused, + void *ucontext __maybe_unused) +{ + exited = 1; + nr_exit = -1; +} + +/* + * This test will start a workload that does nothing then it checks + * if the number of exit event reported by the kernel is 1 or not + * in order to check the kernel returns correct number of event. + */ +static int test__task_exit(struct test_suite *test __maybe_unused, int subtest __maybe_unused) +{ + int err = -1; + union perf_event *event; + struct evsel *evsel; + struct evlist *evlist; + struct target target = { + .uses_mmap = true, + }; + const char *argv[] = { "true", NULL }; + char sbuf[STRERR_BUFSIZE]; + struct perf_cpu_map *cpus; + struct perf_thread_map *threads; + struct mmap *md; + int retry_count = 0; + + signal(SIGCHLD, sig_handler); + + evlist = evlist__new_dummy(); + if (evlist == NULL) { + pr_debug("evlist__new_dummy\n"); + return -1; + } + + /* + * Create maps of threads and cpus to monitor. In this case + * we start with all threads and cpus (-1, -1) but then in + * evlist__prepare_workload we'll fill in the only thread + * we're monitoring, the one forked there. + */ + cpus = perf_cpu_map__new_any_cpu(); + threads = thread_map__new_by_tid(-1); + if (!cpus || !threads) { + err = -ENOMEM; + pr_debug("Not enough memory to create thread/cpu maps\n"); + goto out_delete_evlist; + } + + perf_evlist__set_maps(&evlist->core, cpus, threads); + + err = evlist__prepare_workload(evlist, &target, argv, false, workload_exec_failed_signal); + if (err < 0) { + pr_debug("Couldn't run the workload!\n"); + goto out_delete_evlist; + } + + evsel = evlist__first(evlist); + evsel->core.attr.task = 1; +#ifdef __s390x__ + evsel->core.attr.sample_freq = 1000000; +#else + evsel->core.attr.sample_freq = 1; +#endif + evsel->core.attr.inherit = 0; + evsel->core.attr.watermark = 0; + evsel->core.attr.wakeup_events = 1; + evsel->core.attr.exclude_kernel = 1; + + err = evlist__open(evlist); + if (err < 0) { + pr_debug("Couldn't open the evlist: %s\n", + str_error_r(-err, sbuf, sizeof(sbuf))); + goto out_delete_evlist; + } + + if (evlist__mmap(evlist, 128) < 0) { + pr_debug("failed to mmap events: %d (%s)\n", errno, + str_error_r(errno, sbuf, sizeof(sbuf))); + err = -1; + goto out_delete_evlist; + } + + evlist__start_workload(evlist); + +retry: + md = &evlist->mmap[0]; + if (perf_mmap__read_init(&md->core) < 0) + goto out_init; + + while ((event = perf_mmap__read_event(&md->core)) != NULL) { + if (event->header.type == PERF_RECORD_EXIT) + nr_exit++; + + perf_mmap__consume(&md->core); + } + perf_mmap__read_done(&md->core); + +out_init: + if (!exited || !nr_exit) { + evlist__poll(evlist, -1); + + if (retry_count++ > 1000) { + pr_debug("Failed after retrying 1000 times\n"); + err = -1; + goto out_delete_evlist; + } + + goto retry; + } + + if (nr_exit != 1) { + pr_debug("received %d EXIT records\n", nr_exit); + err = -1; + } + +out_delete_evlist: + perf_cpu_map__put(cpus); + perf_thread_map__put(threads); + evlist__delete(evlist); + return err; +} + +struct test_case tests__task_exit[] = { + TEST_CASE_EXCLUSIVE("Number of exit events of a simple workload", task_exit), + { .name = NULL, } +}; +struct test_suite suite__task_exit = { + .desc = "Number of exit events of a simple workload", + .test_cases = tests__task_exit, +}; -- cgit v1.3.1