From patchwork Tue Dec 14 16:20:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Potapenko X-Patchwork-Id: 12676395 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 92786C433EF for ; Tue, 14 Dec 2021 16:38:58 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 76B996B00A0; Tue, 14 Dec 2021 11:23:27 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 71B256B00A1; Tue, 14 Dec 2021 11:23:27 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 595716B00A2; Tue, 14 Dec 2021 11:23:27 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0247.hostedemail.com [216.40.44.247]) by kanga.kvack.org (Postfix) with ESMTP id 454C76B00A0 for ; Tue, 14 Dec 2021 11:23:27 -0500 (EST) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 05B3882499B9 for ; Tue, 14 Dec 2021 16:23:17 +0000 (UTC) X-FDA: 78916919634.21.B6650AA Received: from mail-ed1-f74.google.com (mail-ed1-f74.google.com [209.85.208.74]) by imf04.hostedemail.com (Postfix) with ESMTP id 9526840010 for ; Tue, 14 Dec 2021 16:23:16 +0000 (UTC) Received: by mail-ed1-f74.google.com with SMTP id v22-20020a50a456000000b003e7cbfe3dfeso17498644edb.11 for ; Tue, 14 Dec 2021 08:23:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=P7FKI/5L9I73iDgWPemkPODmd6ouDJmmgCvvlijOM/4=; b=DI8s2TcL5nly41bQJ32Vbip0YpaHlk/FcTaf0LYqNYofAHYPOXH/t2g8GmRaYbDjPg 0GIT8h94zs1MimNnTN77swOjnnM54PG9XxzRuk/VuvF3osquWjODz8/FaK4VnANPjxNR miLRWofvIbk/i+YYqTNQrIvitA6Gi1yOFDIL0TTggYq67B5WCcrERcUdfROn8qlI+nzT CYFu2MkEU4/jObO/R1HW803ClByvqLM+WCnnkBs50VIGyCk4ZhkUh459pYHnBJO3s7l3 qAw4NDVGeu276pPr53A+434hOWGkB9QTiMw3pllN2zlR7cPyDC75qh0boJlqszdeBJjh yefA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=P7FKI/5L9I73iDgWPemkPODmd6ouDJmmgCvvlijOM/4=; b=RGd2JXpq98dpYYpkKTHvntzjIx9++au/ftXIwpfbu9Lp8GRuKATYa3xNr8m6t+U64c icBp4QQ30oKz3eaZ5ohvWd6b9QfwlKDerD++ypFtnMHy7M6o0le7aPVQUokRmDxeepfl 6g5ezizGlbEfB7c7B5Zmmg2l58u9g7CypgXmyy4Jbf5XUMjCrI75fHL+LjNdyn4Q0iqV X9yYZcPjcP91FmR4OKV2hzAoGWU7+3ArhgyxSmzbfym7OiJ2OdE8tIx58qZ/35CNs25q WVG9Go4qPCD+amvX9VEee1/u605YumIN+3Ul3YSnjDeseBdcwbDDL7yNkHwO5m/IQH+N dMng== X-Gm-Message-State: AOAM530bWFyCGsXDi4F6tvlyn+H5mED/oY/57hmWc4J+HNJLcW6dHOvS 8sYwyl/wGyYbXYgSWYc0ddJPMgYCtNQ= X-Google-Smtp-Source: ABdhPJwC3Znl5BDR1bIFff+vEAjaFA7vGDzKqEApFsi/dZd+jheMERJGedKII4WcV8lBYH3AYoWzy8fTLZ8= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:357e:2b9d:5b13:a652]) (user=glider job=sendgmr) by 2002:a17:906:9144:: with SMTP id y4mr6773278ejw.98.1639498995240; Tue, 14 Dec 2021 08:23:15 -0800 (PST) Date: Tue, 14 Dec 2021 17:20:37 +0100 In-Reply-To: <20211214162050.660953-1-glider@google.com> Message-Id: <20211214162050.660953-31-glider@google.com> Mime-Version: 1.0 References: <20211214162050.660953-1-glider@google.com> X-Mailer: git-send-email 2.34.1.173.g76aa8bc2d0-goog Subject: [PATCH 30/43] kmsan: add tests for KMSAN From: Alexander Potapenko To: glider@google.com Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Ard Biesheuvel , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=DI8s2TcL; spf=pass (imf04.hostedemail.com: domain of 388S4YQYKCHQYdaVWjYggYdW.Ugedafmp-eecnSUc.gjY@flex--glider.bounces.google.com designates 209.85.208.74 as permitted sender) smtp.mailfrom=388S4YQYKCHQYdaVWjYggYdW.Ugedafmp-eecnSUc.gjY@flex--glider.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspamd-Queue-Id: 9526840010 X-Stat-Signature: mmk1fbb8ipt7orjjktgy9icdhkfcom5c X-Rspamd-Server: rspam04 X-HE-Tag: 1639498996-813024 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: The testing module triggers KMSAN warnings in different cases and checks that the errors are properly reported, using console probes to capture the tool's output. Signed-off-by: Alexander Potapenko --- Link: https://linux-review.googlesource.com/id/I49c3f59014cc37fd13541c80beb0b75a75244650 --- lib/Kconfig.kmsan | 16 ++ mm/kmsan/Makefile | 4 + mm/kmsan/kmsan_test.c | 444 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 464 insertions(+) create mode 100644 mm/kmsan/kmsan_test.c diff --git a/lib/Kconfig.kmsan b/lib/Kconfig.kmsan index 02fd6db792b1f..940598f60b3a6 100644 --- a/lib/Kconfig.kmsan +++ b/lib/Kconfig.kmsan @@ -16,3 +16,19 @@ config KMSAN instrumentation provided by Clang and thus requires Clang to build. See for more details. + +if KMSAN + +config KMSAN_KUNIT_TEST + tristate "KMSAN integration test suite" if !KUNIT_ALL_TESTS + default KUNIT_ALL_TESTS + depends on TRACEPOINTS && KUNIT + help + Test suite for KMSAN, testing various error detection scenarios, + and checking that reports are correctly output to console. + + Say Y here if you want the test to be built into the kernel and run + during boot; say M if you want the test to build as a module; say N + if you are unsure. + +endif diff --git a/mm/kmsan/Makefile b/mm/kmsan/Makefile index f57a956cb1c8b..7be6a7e92394f 100644 --- a/mm/kmsan/Makefile +++ b/mm/kmsan/Makefile @@ -20,3 +20,7 @@ CFLAGS_init.o := $(CC_FLAGS_KMSAN_RUNTIME) CFLAGS_instrumentation.o := $(CC_FLAGS_KMSAN_RUNTIME) CFLAGS_report.o := $(CC_FLAGS_KMSAN_RUNTIME) CFLAGS_shadow.o := $(CC_FLAGS_KMSAN_RUNTIME) + +obj-$(CONFIG_KMSAN_KUNIT_TEST) += kmsan_test.o +KMSAN_SANITIZE_kmsan_test.o := y +CFLAGS_kmsan_test.o += $(call cc-disable-warning, uninitialized) diff --git a/mm/kmsan/kmsan_test.c b/mm/kmsan/kmsan_test.c new file mode 100644 index 0000000000000..caf1094411487 --- /dev/null +++ b/mm/kmsan/kmsan_test.c @@ -0,0 +1,444 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Test cases for KMSAN. + * For each test case checks the presence (or absence) of generated reports. + * Relies on 'console' tracepoint to capture reports as they appear in the + * kernel log. + * + * Copyright (C) 2021, Google LLC. + * Author: Alexander Potapenko + * + */ + +#include +#include "kmsan.h" + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static DEFINE_PER_CPU(int, per_cpu_var); + +/* Report as observed from console. */ +static struct { + spinlock_t lock; + bool available; + bool ignore; /* Stop console output collection. */ + char header[256]; +} observed = { + .lock = __SPIN_LOCK_UNLOCKED(observed.lock), +}; + +/* Probe for console output: obtains observed lines of interest. */ +static void probe_console(void *ignore, const char *buf, size_t len) +{ + unsigned long flags; + + if (observed.ignore) + return; + spin_lock_irqsave(&observed.lock, flags); + + if (strnstr(buf, "BUG: KMSAN: ", len)) { + /* + * KMSAN report and related to the test. + * + * The provided @buf is not NUL-terminated; copy no more than + * @len bytes and let strscpy() add the missing NUL-terminator. + */ + strscpy(observed.header, buf, + min(len + 1, sizeof(observed.header))); + WRITE_ONCE(observed.available, true); + observed.ignore = true; + } + spin_unlock_irqrestore(&observed.lock, flags); +} + +/* Check if a report related to the test exists. */ +static bool report_available(void) +{ + return READ_ONCE(observed.available); +} + +/* Information we expect in a report. */ +struct expect_report { + const char *error_type; /* Error type. */ + /* + * Kernel symbol from the error header, or NULL if no report is + * expected. + */ + const char *symbol; +}; + +/* Check observed report matches information in @r. */ +static bool report_matches(const struct expect_report *r) +{ + typeof(observed.header) expected_header; + unsigned long flags; + bool ret = false; + const char *end; + char *cur; + + /* Doubled-checked locking. */ + if (!report_available() || !r->symbol) + return (!report_available() && !r->symbol); + + /* Generate expected report contents. */ + + /* Title */ + cur = expected_header; + end = &expected_header[sizeof(expected_header) - 1]; + + cur += scnprintf(cur, end - cur, "BUG: KMSAN: %s", r->error_type); + + scnprintf(cur, end - cur, " in %s", r->symbol); + /* The exact offset won't match, remove it; also strip module name. */ + cur = strchr(expected_header, '+'); + if (cur) + *cur = '\0'; + + spin_lock_irqsave(&observed.lock, flags); + if (!report_available()) + goto out; /* A new report is being captured. */ + + /* Finally match expected output to what we actually observed. */ + ret = strstr(observed.header, expected_header); +out: + spin_unlock_irqrestore(&observed.lock, flags); + + return ret; +} + +/* ===== Test cases ===== */ + +/* Prevent replacing branch with select in LLVM. */ +static noinline void check_true(char *arg) +{ + pr_info("%s is true\n", arg); +} + +static noinline void check_false(char *arg) +{ + pr_info("%s is false\n", arg); +} + +#define USE(x) \ + do { \ + if (x) \ + check_true(#x); \ + else \ + check_false(#x); \ + } while (0) + +#define EXPECTATION_ETYPE_FN(e, reason, fn) \ + struct expect_report e = { \ + .error_type = reason, \ + .symbol = fn, \ + } + +#define EXPECTATION_NO_REPORT(e) EXPECTATION_ETYPE_FN(e, NULL, NULL) +#define EXPECTATION_UNINIT_VALUE_FN(e, fn) \ + EXPECTATION_ETYPE_FN(e, "uninit-value", fn) +#define EXPECTATION_UNINIT_VALUE(e) EXPECTATION_UNINIT_VALUE_FN(e, __func__) +#define EXPECTATION_USE_AFTER_FREE(e) \ + EXPECTATION_ETYPE_FN(e, "use-after-free", __func__) + +static int signed_sum3(int a, int b, int c) +{ + return a + b + c; +} + +static void test_uninit_kmalloc(struct kunit *test) +{ + EXPECTATION_UNINIT_VALUE(expect); + int *ptr; + + kunit_info(test, "uninitialized kmalloc test (UMR report)\n"); + ptr = kmalloc(sizeof(int), GFP_KERNEL); + USE(*ptr); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static void test_init_kmalloc(struct kunit *test) +{ + EXPECTATION_NO_REPORT(expect); + int *ptr; + + kunit_info(test, "initialized kmalloc test (no reports)\n"); + ptr = kmalloc(sizeof(int), GFP_KERNEL); + memset(ptr, 0, sizeof(int)); + USE(*ptr); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static void test_init_kzalloc(struct kunit *test) +{ + EXPECTATION_NO_REPORT(expect); + int *ptr; + + kunit_info(test, "initialized kzalloc test (no reports)\n"); + ptr = kzalloc(sizeof(int), GFP_KERNEL); + USE(*ptr); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static void test_uninit_multiple_args(struct kunit *test) +{ + EXPECTATION_UNINIT_VALUE(expect); + volatile char b = 3, c; + volatile int a; + + kunit_info(test, "uninitialized local passed to fn (UMR report)\n"); + USE(signed_sum3(a, b, c)); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static void test_uninit_stack_var(struct kunit *test) +{ + EXPECTATION_UNINIT_VALUE(expect); + volatile int cond; + + kunit_info(test, "uninitialized stack variable (UMR report)\n"); + USE(cond); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static void test_init_stack_var(struct kunit *test) +{ + EXPECTATION_NO_REPORT(expect); + volatile int cond = 1; + + kunit_info(test, "initialized stack variable (no reports)\n"); + USE(cond); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static noinline void two_param_fn_2(int arg1, int arg2) +{ + USE(arg1); + USE(arg2); +} + +static noinline void one_param_fn(int arg) +{ + two_param_fn_2(arg, arg); + USE(arg); +} + +static noinline void two_param_fn(int arg1, int arg2) +{ + int init = 0; + + one_param_fn(init); + USE(arg1); + USE(arg2); +} + +static void test_params(struct kunit *test) +{ + EXPECTATION_UNINIT_VALUE_FN(expect, "two_param_fn"); + volatile int uninit, init = 1; + + kunit_info(test, + "uninit passed through a function parameter (UMR report)\n"); + two_param_fn(uninit, init); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static noinline void do_uninit_local_array(char *array, int start, int stop) +{ + volatile char uninit; + int i; + + for (i = start; i < stop; i++) + array[i] = uninit; +} + +static void test_uninit_kmsan_check_memory(struct kunit *test) +{ + EXPECTATION_UNINIT_VALUE_FN(expect, "test_uninit_kmsan_check_memory"); + volatile char local_array[8]; + + kunit_info( + test, + "kmsan_check_memory() called on uninit local (UMR report)\n"); + do_uninit_local_array((char *)local_array, 5, 7); + + kmsan_check_memory((char *)local_array, 8); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static void test_init_kmsan_vmap_vunmap(struct kunit *test) +{ + EXPECTATION_NO_REPORT(expect); + const int npages = 2; + struct page **pages; + void *vbuf; + int i; + + kunit_info(test, "pages initialized via vmap (no reports)\n"); + + pages = kmalloc_array(npages, sizeof(struct page), GFP_KERNEL); + for (i = 0; i < npages; i++) + pages[i] = alloc_page(GFP_KERNEL); + vbuf = vmap(pages, npages, VM_MAP, PAGE_KERNEL); + memset(vbuf, 0xfe, npages * PAGE_SIZE); + for (i = 0; i < npages; i++) + kmsan_check_memory(page_address(pages[i]), PAGE_SIZE); + + if (vbuf) + vunmap(vbuf); + for (i = 0; i < npages; i++) + if (pages[i]) + __free_page(pages[i]); + kfree(pages); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static void test_init_vmalloc(struct kunit *test) +{ + EXPECTATION_NO_REPORT(expect); + int npages = 8, i; + char *buf; + + kunit_info(test, "pages initialized via vmap (no reports)\n"); + buf = vmalloc(PAGE_SIZE * npages); + buf[0] = 1; + memset(buf, 0xfe, PAGE_SIZE * npages); + USE(buf[0]); + for (i = 0; i < npages; i++) + kmsan_check_memory(&buf[PAGE_SIZE * i], PAGE_SIZE); + vfree(buf); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static void test_uaf(struct kunit *test) +{ + EXPECTATION_USE_AFTER_FREE(expect); + volatile int value; + volatile int *var; + + kunit_info(test, "use-after-free in kmalloc-ed buffer (UMR report)\n"); + var = kmalloc(80, GFP_KERNEL); + var[3] = 0xfeedface; + kfree((int *)var); + /* Copy the invalid value before checking it. */ + value = var[3]; + USE(value); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static void test_percpu_propagate(struct kunit *test) +{ + EXPECTATION_UNINIT_VALUE(expect); + volatile int uninit, check; + + kunit_info(test, + "uninit local stored to per_cpu memory (UMR report)\n"); + + this_cpu_write(per_cpu_var, uninit); + check = this_cpu_read(per_cpu_var); + USE(check); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static void test_printk(struct kunit *test) +{ + EXPECTATION_UNINIT_VALUE_FN(expect, "number"); + volatile int uninit; + + kunit_info(test, "uninit local passed to pr_info() (UMR report)\n"); + pr_info("%px contains %d\n", &uninit, uninit); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static struct kunit_case kmsan_test_cases[] = { + KUNIT_CASE(test_uninit_kmalloc), + KUNIT_CASE(test_init_kmalloc), + KUNIT_CASE(test_init_kzalloc), + KUNIT_CASE(test_uninit_multiple_args), + KUNIT_CASE(test_uninit_stack_var), + KUNIT_CASE(test_init_stack_var), + KUNIT_CASE(test_params), + KUNIT_CASE(test_uninit_kmsan_check_memory), + KUNIT_CASE(test_init_kmsan_vmap_vunmap), + KUNIT_CASE(test_init_vmalloc), + KUNIT_CASE(test_uaf), + KUNIT_CASE(test_percpu_propagate), + KUNIT_CASE(test_printk), + {}, +}; + +/* ===== End test cases ===== */ + +static int test_init(struct kunit *test) +{ + unsigned long flags; + + spin_lock_irqsave(&observed.lock, flags); + observed.header[0] = '\0'; + observed.ignore = false; + observed.available = false; + spin_unlock_irqrestore(&observed.lock, flags); + + return 0; +} + +static void test_exit(struct kunit *test) +{ +} + +static struct kunit_suite kmsan_test_suite = { + .name = "kmsan", + .test_cases = kmsan_test_cases, + .init = test_init, + .exit = test_exit, +}; +static struct kunit_suite *kmsan_test_suites[] = { &kmsan_test_suite, NULL }; + +static void register_tracepoints(struct tracepoint *tp, void *ignore) +{ + check_trace_callback_type_console(probe_console); + if (!strcmp(tp->name, "console")) + WARN_ON(tracepoint_probe_register(tp, probe_console, NULL)); +} + +static void unregister_tracepoints(struct tracepoint *tp, void *ignore) +{ + if (!strcmp(tp->name, "console")) + tracepoint_probe_unregister(tp, probe_console, NULL); +} + +/* + * We only want to do tracepoints setup and teardown once, therefore we have to + * customize the init and exit functions and cannot rely on kunit_test_suite(). + */ +static int __init kmsan_test_init(void) +{ + /* + * Because we want to be able to build the test as a module, we need to + * iterate through all known tracepoints, since the static registration + * won't work here. + */ + for_each_kernel_tracepoint(register_tracepoints, NULL); + return __kunit_test_suites_init(kmsan_test_suites); +} + +static void kmsan_test_exit(void) +{ + __kunit_test_suites_exit(kmsan_test_suites); + for_each_kernel_tracepoint(unregister_tracepoints, NULL); + tracepoint_synchronize_unregister(); +} + +late_initcall_sync(kmsan_test_init); +module_exit(kmsan_test_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Alexander Potapenko ");