Instrument copy_from_kernel_nofault(), copy_to_kernel_nofault() with instrument_memcpy_before() for KASAN, KCSAN checks and instrument_memcpy_after() for KMSAN. Tested on x86_64 and arm64 with CONFIG_KASAN_SW_TAGS. On arm64 with CONFIG_KASAN_HW_TAGS, kunit test currently fails. Need more clarification on it - currently, disabled in kunit test. Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxx> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=210505 Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@xxxxxxxxx> --- mm/kasan/kasan_test.c | 31 +++++++++++++++++++++++++++++++ mm/maccess.c | 8 ++++++-- 2 files changed, 37 insertions(+), 2 deletions(-) diff --git a/mm/kasan/kasan_test.c b/mm/kasan/kasan_test.c index 567d33b49..329d81518 100644 --- a/mm/kasan/kasan_test.c +++ b/mm/kasan/kasan_test.c @@ -1944,6 +1944,36 @@ static void match_all_mem_tag(struct kunit *test) kfree(ptr); } +static void copy_from_to_kernel_nofault_oob(struct kunit *test) +{ + char *ptr; + char buf[128]; + size_t size = sizeof(buf); + + /* Not detecting fails currently with HW_TAGS */ + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_HW_TAGS); + + ptr = kmalloc(size - KASAN_GRANULE_SIZE, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + OPTIMIZER_HIDE_VAR(ptr); + + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) { + /* Check that the returned pointer is tagged. */ + KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN); + KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL); + } + + KUNIT_EXPECT_KASAN_FAIL(test, + copy_from_kernel_nofault(&buf[0], ptr, size)); + KUNIT_EXPECT_KASAN_FAIL(test, + copy_from_kernel_nofault(ptr, &buf[0], size)); + KUNIT_EXPECT_KASAN_FAIL(test, + copy_to_kernel_nofault(&buf[0], ptr, size)); + KUNIT_EXPECT_KASAN_FAIL(test, + copy_to_kernel_nofault(ptr, &buf[0], size)); + kfree(ptr); +} + static struct kunit_case kasan_kunit_test_cases[] = { KUNIT_CASE(kmalloc_oob_right), KUNIT_CASE(kmalloc_oob_left), @@ -2017,6 +2047,7 @@ static struct kunit_case kasan_kunit_test_cases[] = { KUNIT_CASE(match_all_not_assigned), KUNIT_CASE(match_all_ptr_tag), KUNIT_CASE(match_all_mem_tag), + KUNIT_CASE(copy_from_to_kernel_nofault_oob), {} }; diff --git a/mm/maccess.c b/mm/maccess.c index 518a25667..2c4251df4 100644 --- a/mm/maccess.c +++ b/mm/maccess.c @@ -15,7 +15,7 @@ bool __weak copy_from_kernel_nofault_allowed(const void *unsafe_src, #define copy_from_kernel_nofault_loop(dst, src, len, type, err_label) \ while (len >= sizeof(type)) { \ - __get_kernel_nofault(dst, src, type, err_label); \ + __get_kernel_nofault(dst, src, type, err_label); \ dst += sizeof(type); \ src += sizeof(type); \ len -= sizeof(type); \ @@ -32,6 +32,7 @@ long copy_from_kernel_nofault(void *dst, const void *src, size_t size) return -ERANGE; pagefault_disable(); + instrument_memcpy_before(dst, src, size); if (!(align & 7)) copy_from_kernel_nofault_loop(dst, src, size, u64, Efault); if (!(align & 3)) @@ -39,6 +40,7 @@ long copy_from_kernel_nofault(void *dst, const void *src, size_t size) if (!(align & 1)) copy_from_kernel_nofault_loop(dst, src, size, u16, Efault); copy_from_kernel_nofault_loop(dst, src, size, u8, Efault); + instrument_memcpy_after(dst, src, size, 0); pagefault_enable(); return 0; Efault: @@ -49,7 +51,7 @@ EXPORT_SYMBOL_GPL(copy_from_kernel_nofault); #define copy_to_kernel_nofault_loop(dst, src, len, type, err_label) \ while (len >= sizeof(type)) { \ - __put_kernel_nofault(dst, src, type, err_label); \ + __put_kernel_nofault(dst, src, type, err_label); \ dst += sizeof(type); \ src += sizeof(type); \ len -= sizeof(type); \ @@ -63,6 +65,7 @@ long copy_to_kernel_nofault(void *dst, const void *src, size_t size) align = (unsigned long)dst | (unsigned long)src; pagefault_disable(); + instrument_memcpy_before(dst, src, size); if (!(align & 7)) copy_to_kernel_nofault_loop(dst, src, size, u64, Efault); if (!(align & 3)) @@ -70,6 +73,7 @@ long copy_to_kernel_nofault(void *dst, const void *src, size_t size) if (!(align & 1)) copy_to_kernel_nofault_loop(dst, src, size, u16, Efault); copy_to_kernel_nofault_loop(dst, src, size, u8, Efault); + instrument_memcpy_after(dst, src, size, 0); pagefault_enable(); return 0; Efault: -- 2.34.1
