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/bench/kallsyms-parse.c | 75 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) create mode 100644 tools/perf/bench/kallsyms-parse.c (limited to 'tools/perf/bench/kallsyms-parse.c') diff --git a/tools/perf/bench/kallsyms-parse.c b/tools/perf/bench/kallsyms-parse.c new file mode 100644 index 000000000..2b0d0f980 --- /dev/null +++ b/tools/perf/bench/kallsyms-parse.c @@ -0,0 +1,75 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Benchmark of /proc/kallsyms parsing. + * + * Copyright 2020 Google LLC. + */ +#include +#include "bench.h" +#include "../util/stat.h" +#include +#include +#include + +static unsigned int iterations = 100; + +static const struct option options[] = { + OPT_UINTEGER('i', "iterations", &iterations, + "Number of iterations used to compute average"), + OPT_END() +}; + +static const char *const bench_usage[] = { + "perf bench internals kallsyms-parse ", + NULL +}; + +static int bench_process_symbol(void *arg __maybe_unused, + const char *name __maybe_unused, + char type __maybe_unused, + u64 start __maybe_unused) +{ + return 0; +} + +static int do_kallsyms_parse(void) +{ + struct timeval start, end, diff; + u64 runtime_us; + unsigned int i; + double time_average, time_stddev; + int err; + struct stats time_stats; + + init_stats(&time_stats); + + for (i = 0; i < iterations; i++) { + gettimeofday(&start, NULL); + err = kallsyms__parse("/proc/kallsyms", NULL, + bench_process_symbol); + if (err) + return err; + + gettimeofday(&end, NULL); + timersub(&end, &start, &diff); + runtime_us = diff.tv_sec * USEC_PER_SEC + diff.tv_usec; + update_stats(&time_stats, runtime_us); + } + + time_average = avg_stats(&time_stats) / USEC_PER_MSEC; + time_stddev = stddev_stats(&time_stats) / USEC_PER_MSEC; + printf(" Average kallsyms__parse took: %.3f ms (+- %.3f ms)\n", + time_average, time_stddev); + return 0; +} + +int bench_kallsyms_parse(int argc, const char **argv) +{ + argc = parse_options(argc, argv, options, bench_usage, 0); + if (argc) { + usage_with_options(bench_usage, options); + exit(EXIT_FAILURE); + } + + return do_kallsyms_parse(); +} -- cgit v1.3.1