On Tue, Feb 09, 2021 at 11:18PM -0600, Timur Tabi wrote: > [accidentally sent from the wrong email address, so resending] > > [The list of email addresses on CC: is getting quite lengthy, > so I hope I've included everyone.] > > Although hashing addresses printed via printk does make the > kernel more secure, it interferes with debugging, especially > with some functions like print_hex_dump() which always uses > hashed addresses. > > To avoid having to choose between %p and %px, it's easier to > add a kernel command line that treats all %p as %px. This > encourages developers to use %p more without making debugging > more difficult. > > Patches #1 and #2 upgrade the kselftest framework so that > it can report on tests that were skipped outright. This > is needed for the test_printf module which will now skip > %p hashing tests if hashing is disabled. > > Patch #2 upgrades the printf library to check the command > line. It also updates test_printf(). > > Timur Tabi (3): > lib/test_printf: use KSTM_MODULE_GLOBALS macro > kselftest: add support for skipped tests > [v2] lib/vsprintf: make-printk-non-secret printks all addresses as > unhashed > > .../admin-guide/kernel-parameters.txt | 15 +++++++ > lib/test_printf.c | 12 +++++- > lib/vsprintf.c | 40 ++++++++++++++++++- > tools/testing/selftests/kselftest_module.h | 18 ++++++--- > 4 files changed, 75 insertions(+), 10 deletions(-) I wanted to test this for deciding if we can show sensitive info in KFENCE reports, which works just fine now that debug_never_hash_pointers is non-static. FWIW, Acked-by: Marco Elver <elver@xxxxxxxxxx> But unfortunately this series broke some other test: | In file included from lib/test_bitmap.c:17: | lib/test_bitmap.c: In function ‘test_bitmap_init’: | lib/../tools/testing/selftests/kselftest_module.h:45:48: error: ‘skipped_tests’ undeclared (first use in this function); did you mean ‘failed_tests’? | 45 | return kstm_report(total_tests, failed_tests, skipped_tests); \ | | ^~~~~~~~~~~~~ | lib/test_bitmap.c:637:1: note: in expansion of macro ‘KSTM_MODULE_LOADERS’ | 637 | KSTM_MODULE_LOADERS(test_bitmap); | | ^~~~~~~~~~~~~~~~~~~ | lib/../tools/testing/selftests/kselftest_module.h:45:48: note: each undeclared identifier is reported only once for each function it appears in | 45 | return kstm_report(total_tests, failed_tests, skipped_tests); \ | | ^~~~~~~~~~~~~ | lib/test_bitmap.c:637:1: note: in expansion of macro ‘KSTM_MODULE_LOADERS’ | 637 | KSTM_MODULE_LOADERS(test_bitmap); | | ^~~~~~~~~~~~~~~~~~~ | lib/../tools/testing/selftests/kselftest_module.h:46:1: error: control reaches end of non-void function [-Werror=return-type] | 46 | } \ | | ^ | lib/test_bitmap.c:637:1: note: in expansion of macro ‘KSTM_MODULE_LOADERS’ | 637 | KSTM_MODULE_LOADERS(test_bitmap); | | ^~~~~~~~~~~~~~~~~~~ My allyesconfig build suggests test_bitmap.c is the only one, so it should probably be fixed up in this series. Thanks, -- Marco
