From 2852ca7fba9f77b204f0fe953b31fadd0057c936 Mon Sep 17 00:00:00 2001 From: David Gow Date: Fri, 1 Jul 2022 16:47:41 +0800 Subject: panic: Taint kernel if tests are run Most in-kernel tests (such as KUnit tests) are not supposed to run on production systems: they may do deliberately illegal things to trigger errors, and have security implications (for example, KUnit assertions will often deliberately leak kernel addresses). Add a new taint type, TAINT_TEST to signal that a test has been run. This will be printed as 'N' (originally for kuNit, as every other sensible letter was taken.) This should discourage people from running these tests on production systems, and to make it easier to tell if tests have been run accidentally (by loading the wrong configuration, etc.) Acked-by: Luis Chamberlain Reviewed-by: Brendan Higgins Signed-off-by: David Gow Signed-off-by: Shuah Khan --- kernel/panic.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/panic.c b/kernel/panic.c index a3c758dba15a..6b3369e21026 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -428,6 +428,7 @@ const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { [ TAINT_LIVEPATCH ] = { 'K', ' ', true }, [ TAINT_AUX ] = { 'X', ' ', true }, [ TAINT_RANDSTRUCT ] = { 'T', ' ', true }, + [ TAINT_TEST ] = { 'N', ' ', true }, }; /** -- cgit v1.2.3-59-g8ed1b From 74829ddf5977567d77440150d72d4c0c5c427446 Mon Sep 17 00:00:00 2001 From: David Gow Date: Fri, 8 Jul 2022 12:48:45 +0800 Subject: module: panic: Taint the kernel when selftest modules load Taint the kernel with TAINT_TEST whenever a test module loads, by adding a new "TEST" module property, and setting it for all modules in the tools/testing directory. This property can also be set manually, for tests which live outside the tools/testing directory with: MODULE_INFO(test, "Y"); Reviewed-by: Luis Chamberlain Reviewed-by: Aaron Tomlin Acked-by: Brendan Higgins Signed-off-by: David Gow Signed-off-by: Shuah Khan --- kernel/module/main.c | 7 +++++++ scripts/mod/modpost.c | 3 +++ 2 files changed, 10 insertions(+) (limited to 'kernel') diff --git a/kernel/module/main.c b/kernel/module/main.c index fed58d30725d..4723f1316709 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -1988,6 +1988,13 @@ static int check_modinfo(struct module *mod, struct load_info *info, int flags) /* Set up license info based on the info section */ set_license(mod, get_modinfo(info, "license")); + if (get_modinfo(info, "test")) { + if (!test_taint(TAINT_TEST)) + pr_warn("%s: loading test module taints kernel.\n", + mod->name); + add_taint_module(mod, TAINT_TEST, LOCKDEP_STILL_OK); + } + return 0; } diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 29d5a841e215..5937212b4433 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -2191,6 +2191,9 @@ static void add_header(struct buffer *b, struct module *mod) if (strstarts(mod->name, "drivers/staging")) buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n"); + + if (strstarts(mod->name, "tools/testing")) + buf_printf(b, "\nMODULE_INFO(test, \"Y\");\n"); } static void add_exported_symbols(struct buffer *buf, struct module *mod) -- cgit v1.2.3-59-g8ed1b From 3d6e44623841c8b82c2157f2f749019803fb238a Mon Sep 17 00:00:00 2001 From: Jeremy Kerr Date: Sat, 9 Jul 2022 11:19:57 +0800 Subject: kunit: unify module and builtin suite definitions MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently, KUnit runs built-in tests and tests loaded from modules differently. For built-in tests, the kunit_test_suite{,s}() macro adds a list of suites in the .kunit_test_suites linker section. However, for kernel modules, a module_init() function is used to run the test suites. This causes problems if tests are included in a module which already defines module_init/exit_module functions, as they'll conflict with the kunit-provided ones. This change removes the kunit-defined module inits, and instead parses the kunit tests from their own section in the module. After module init, we call __kunit_test_suites_init() on the contents of that section, which prepares and runs the suite. This essentially unifies the module- and non-module kunit init formats. Tested-by: Maíra Canal Reviewed-by: Brendan Higgins Signed-off-by: Jeremy Kerr Signed-off-by: Daniel Latypov Signed-off-by: David Gow Signed-off-by: Shuah Khan --- include/kunit/test.h | 49 ++++++----------------------------------------- include/linux/module.h | 5 +++++ kernel/module/main.c | 6 ++++++ lib/kunit/test.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++++- 4 files changed, 68 insertions(+), 44 deletions(-) (limited to 'kernel') diff --git a/include/kunit/test.h b/include/kunit/test.h index 7646d1bcf685..cb155d3da284 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -250,42 +250,9 @@ static inline int kunit_run_all_tests(void) } #endif /* IS_BUILTIN(CONFIG_KUNIT) */ -#ifdef MODULE -/** - * kunit_test_suites_for_module() - used to register one or more - * &struct kunit_suite with KUnit. - * - * @__suites: a statically allocated list of &struct kunit_suite. - * - * Registers @__suites with the test framework. See &struct kunit_suite for - * more information. - * - * If a test suite is built-in, module_init() gets translated into - * an initcall which we don't want as the idea is that for builtins - * the executor will manage execution. So ensure we do not define - * module_{init|exit} functions for the builtin case when registering - * suites via kunit_test_suites() below. - */ -#define kunit_test_suites_for_module(__suites) \ - static int __init kunit_test_suites_init(void) \ - { \ - return __kunit_test_suites_init(__suites); \ - } \ - module_init(kunit_test_suites_init); \ - \ - static void __exit kunit_test_suites_exit(void) \ - { \ - return __kunit_test_suites_exit(__suites); \ - } \ - module_exit(kunit_test_suites_exit) \ - MODULE_INFO(test, "Y"); -#else -#define kunit_test_suites_for_module(__suites) -#endif /* MODULE */ - #define __kunit_test_suites(unique_array, unique_suites, ...) \ + MODULE_INFO(test, "Y"); \ static struct kunit_suite *unique_array[] = { __VA_ARGS__, NULL }; \ - kunit_test_suites_for_module(unique_array); \ static struct kunit_suite **unique_suites \ __used __section(".kunit_test_suites") = unique_array @@ -295,16 +262,12 @@ static inline int kunit_run_all_tests(void) * * @__suites: a statically allocated list of &struct kunit_suite. * - * Registers @suites with the test framework. See &struct kunit_suite for - * more information. - * - * When builtin, KUnit tests are all run via executor; this is done - * by placing the array of struct kunit_suite * in the .kunit_test_suites - * ELF section. + * Registers @suites with the test framework. + * This is done by placing the array of struct kunit_suite * in the + * .kunit_test_suites ELF section. * - * An alternative is to build the tests as a module. Because modules do not - * support multiple initcall()s, we need to initialize an array of suites for a - * module. + * When builtin, KUnit tests are all run via the executor at boot, and when + * built as a module, they run on module load. * */ #define kunit_test_suites(__suites...) \ diff --git a/include/linux/module.h b/include/linux/module.h index abd9fa916b7d..2490223c975d 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -505,6 +505,11 @@ struct module { int num_static_call_sites; struct static_call_site *static_call_sites; #endif +#if IS_ENABLED(CONFIG_KUNIT) + int num_kunit_suites; + struct kunit_suite ***kunit_suites; +#endif + #ifdef CONFIG_LIVEPATCH bool klp; /* Is this a livepatch module? */ diff --git a/kernel/module/main.c b/kernel/module/main.c index 4723f1316709..324a770f789c 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -2094,6 +2094,12 @@ static int find_module_sections(struct module *mod, struct load_info *info) sizeof(*mod->static_call_sites), &mod->num_static_call_sites); #endif +#ifdef CONFIG_KUNIT + mod->kunit_suites = section_objs(info, ".kunit_test_suites", + sizeof(*mod->kunit_suites), + &mod->num_kunit_suites); +#endif + mod->extable = section_objs(info, "__ex_table", sizeof(*mod->extable), &mod->num_exentries); diff --git a/lib/kunit/test.c b/lib/kunit/test.c index 8b11552dc215..246645eb3cef 100644 --- a/lib/kunit/test.c +++ b/lib/kunit/test.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -613,6 +614,49 @@ void __kunit_test_suites_exit(struct kunit_suite **suites) } EXPORT_SYMBOL_GPL(__kunit_test_suites_exit); +#ifdef CONFIG_MODULES +static void kunit_module_init(struct module *mod) +{ + unsigned int i; + + for (i = 0; i < mod->num_kunit_suites; i++) + __kunit_test_suites_init(mod->kunit_suites[i]); +} + +static void kunit_module_exit(struct module *mod) +{ + unsigned int i; + + for (i = 0; i < mod->num_kunit_suites; i++) + __kunit_test_suites_exit(mod->kunit_suites[i]); +} + +static int kunit_module_notify(struct notifier_block *nb, unsigned long val, + void *data) +{ + struct module *mod = data; + + switch (val) { + case MODULE_STATE_LIVE: + kunit_module_init(mod); + break; + case MODULE_STATE_GOING: + kunit_module_exit(mod); + break; + case MODULE_STATE_COMING: + case MODULE_STATE_UNFORMED: + break; + } + + return 0; +} + +static struct notifier_block kunit_mod_nb = { + .notifier_call = kunit_module_notify, + .priority = 0, +}; +#endif + struct kunit_kmalloc_array_params { size_t n; size_t size; @@ -707,13 +751,19 @@ EXPORT_SYMBOL_GPL(kunit_cleanup); static int __init kunit_init(void) { kunit_debugfs_init(); - +#ifdef CONFIG_MODULES + return register_module_notifier(&kunit_mod_nb); +#else return 0; +#endif } late_initcall(kunit_init); static void __exit kunit_exit(void) { +#ifdef CONFIG_MODULES + unregister_module_notifier(&kunit_mod_nb); +#endif kunit_debugfs_cleanup(); } module_exit(kunit_exit); -- cgit v1.2.3-59-g8ed1b From 426752b25377487807455bb2f55c09b01bb6aaf0 Mon Sep 17 00:00:00 2001 From: David Gow Date: Fri, 15 Jul 2022 14:40:52 +0800 Subject: kcsan: test: Add a .kunitconfig to run KCSAN tests Add a .kunitconfig file, which provides a default, working config for running the KCSAN tests. Note that it needs to run on an SMP machine, so to run under kunit_tool, the --qemu_args option should be used (on a supported architecture, like x86_64). For example: ./tools/testing/kunit/kunit.py run --arch=x86_64 --qemu_args='-smp 8' --kunitconfig=kernel/kcsan Signed-off-by: David Gow Reviewed-by: Marco Elver Acked-by: Brendan Higgins Tested-by: Daniel Latypov Signed-off-by: Shuah Khan --- kernel/kcsan/.kunitconfig | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) create mode 100644 kernel/kcsan/.kunitconfig (limited to 'kernel') diff --git a/kernel/kcsan/.kunitconfig b/kernel/kcsan/.kunitconfig new file mode 100644 index 000000000000..e82f0f52ab0a --- /dev/null +++ b/kernel/kcsan/.kunitconfig @@ -0,0 +1,24 @@ +# Note that the KCSAN tests need to run on an SMP setup. +# Under kunit_tool, this can be done by using the --qemu_args +# option to configure a machine with several cores. For example: +# ./tools/testing/kunit/kunit.py run --kunitconfig=kernel/kcsan \ +# --arch=x86_64 --qemu_args="-smp 8" + +CONFIG_KUNIT=y + +CONFIG_DEBUG_KERNEL=y + +# Need some level of concurrency to test a concurrency sanitizer. +CONFIG_SMP=y + +CONFIG_KCSAN=y +CONFIG_KCSAN_KUNIT_TEST=y + +# Set these if you want to run test_barrier_nothreads +#CONFIG_KCSAN_STRICT=y +#CONFIG_KCSAN_WEAK_MEMORY=y + +# This prevents the test from timing out on many setups. Feel free to remove +# (or alter) this, in conjunction with setting a different test timeout with, +# for example, the --timeout kunit_tool option. +CONFIG_KCSAN_REPORT_ONCE_IN_MS=100 -- cgit v1.2.3-59-g8ed1b