Instrument copy_from_kernel_nofault(), copy_to_kernel_nofault(), strncpy_from_kernel_nofault() where __put_kernel_nofault, __get_kernel_nofault macros are used. __get_kernel_nofault needs instrument_memcpy_before() which handles KASAN, KCSAN checks for src, dst address, whereas for __put_kernel_nofault macro, instrument_write() check should be enough as it's validated via kmsan_copy_to_user() in instrument_put_user(). copy_from_to_kernel_nofault_oob() kunit test triggers 4 KASAN OOB bug reports as expected, one for each copy_from/to_kernel_nofault call. Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxx> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=210505 Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@xxxxxxxxx> --- v3: changed kunit test from UAF to OOB case and git commit message. v4: updated a grammar in git commit message. v5: copy_from_to_kernel_nofault_oob() works only for x86 arch, remove instrument_get_user() from __get_user_size on !CONFIG_CC_HAS_ASM_GOTO_OUTPUT --- arch/x86/include/asm/uaccess.h | 3 +++ mm/kasan/kasan_test.c | 23 +++++++++++++++++++++++ 2 files changed, 26 insertions(+) diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 3a7755c1a441..e8e5185dd65c 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -620,6 +620,7 @@ do { \ #ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT #define __get_kernel_nofault(dst, src, type, err_label) \ + instrument_memcpy_before(dst, src, sizeof(type)); \ __get_user_size(*((type *)(dst)), (__force type __user *)(src), \ sizeof(type), err_label) #else // !CONFIG_CC_HAS_ASM_GOTO_OUTPUT @@ -627,6 +628,7 @@ do { \ do { \ int __kr_err; \ \ + instrument_memcpy_before(dst, src, sizeof(type)); \ __get_user_size(*((type *)(dst)), (__force type __user *)(src), \ sizeof(type), __kr_err); \ if (unlikely(__kr_err)) \ @@ -635,6 +637,7 @@ do { \ #endif // CONFIG_CC_HAS_ASM_GOTO_OUTPUT #define __put_kernel_nofault(dst, src, type, err_label) \ + instrument_write(dst, sizeof(type)); \ __put_user_size(*((type *)(src)), (__force type __user *)(dst), \ sizeof(type), err_label) diff --git a/mm/kasan/kasan_test.c b/mm/kasan/kasan_test.c index 567d33b493e2..c369a5b1c6a7 100644 --- a/mm/kasan/kasan_test.c +++ b/mm/kasan/kasan_test.c @@ -1944,6 +1944,28 @@ 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); + + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_X86); + + ptr = kmalloc(size - KASAN_GRANULE_SIZE, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + 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 +2039,7 @@ 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), {} }; -- 2.34.1
