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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id e13sm20544264pfi.210.2021.08.24.19.32.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Aug 2021 19:32:52 -0700 (PDT) Date: Tue, 24 Aug 2021 19:32:51 -0700 From: Kees Cook To: David Gow Cc: Linux Kernel Mailing List , Rasmus Villemoes , Daniel Micay , Francis Laniel , Bart Van Assche , Linux Memory Management List , clang-built-linux@googlegroups.com, linux-hardening@vger.kernel.org Subject: Re: [PATCH for-next 21/25] lib: Introduce CONFIG_TEST_MEMCPY Message-ID: <202108241921.26866A8F@keescook> References: <20210822075122.864511-1-keescook@chromium.org> <20210822075122.864511-22-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 24, 2021 at 03:00:19PM +0800, David Gow wrote: > On Sun, Aug 22, 2021 at 3:56 PM Kees Cook wrote: > > > > Before changing anything about memcpy(), memmove(), and memset(), add > > run-time tests to check basic behaviors for any regressions. > > > > Signed-off-by: Kees Cook > > --- > > Thanks for adding a KUnit test here: it's great to have better > coverage of some of these basic functions! > > There's a name mismatch with the Kconfig entry and the Makefile, > otherwise this looks good and works fine on my machine (under both UML > and qemu/x86_64). Hah! Whoops. Thanks for noticing this -- I think I didn't use a clean tree and never noticed because I had the old module. > It would be possible to split these tests up further if you wanted, > which could be useful if there's a desire to track the individual > assertion results independently. That's probably what I'd've done, but > It's a matter of personal preference either way, though: the tests > aren't absurdly huge or over-complicated as-is. Noted. Yeah, for me, I think it's "does memcpy work or not?" and each of the EXPECTs are required, so it felt like 1 test with lots of EXPECTs. > > +FORTIFY_SOURCE > > +M: Kees Cook > > +L: linux-hardening@vger.kernel.org > > +S: Supported > > +F: include/linux/fortify-string.h > > +F: lib/test_fortify/* > > +F: scripts/test_fortify.sh > > +K: \b__NO_FORTIFY\b > > + > > Do you want this to be part of the memcpy() KUnit test commit, or is > it better suited in one of the changes to the actual fortify stuff? Whoops, thanks. This got --fixup'ed into the wrong patch. I've moved it now. > > FPGA DFL DRIVERS > > M: Wu Hao > > R: Tom Rix > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > > index 831212722924..9199be57ba2a 100644 > > --- a/lib/Kconfig.debug > > +++ b/lib/Kconfig.debug > > @@ -2467,6 +2467,17 @@ config RATIONAL_KUNIT_TEST > > > > If unsure, say N. > > > > +config MEMCPY_KUNIT_TEST > > + tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS > > + depends on KUNIT > > + default KUNIT_ALL_TESTS > > + help > > + Builds unit tests for memcpy(), memmove(), and memset() functions. > > + For more information on KUnit and unit tests in general please refer > > + to the KUnit documentation in Documentation/dev-tools/kunit/. > > + > > + If unsure, say N. > > + > > config TEST_UDELAY > > tristate "udelay test driver" > > help > > diff --git a/lib/Makefile b/lib/Makefile > > index bd17c2bf43e1..8a4c8bdb38a2 100644 > > --- a/lib/Makefile > > +++ b/lib/Makefile > > @@ -77,6 +77,7 @@ obj-$(CONFIG_TEST_MIN_HEAP) += test_min_heap.o > > obj-$(CONFIG_TEST_LKM) += test_module.o > > obj-$(CONFIG_TEST_VMALLOC) += test_vmalloc.o > > obj-$(CONFIG_TEST_OVERFLOW) += test_overflow.o > > +obj-$(CONFIG_TEST_MEMCPY) += test_memcpy.o > > This doesn't match CONFIG_MEMCPY_KUNIT_TEST above, so the test is > never compiled in. Now fixed to be CONFIG_MEMCPY_KUNIT_TEST. > > > obj-$(CONFIG_TEST_RHASHTABLE) += test_rhashtable.o > > obj-$(CONFIG_TEST_SORT) += test_sort.o > > obj-$(CONFIG_TEST_USER_COPY) += test_user_copy.o > > diff --git a/lib/test_memcpy.c b/lib/test_memcpy.c > > new file mode 100644 > > index 000000000000..ec546cec883e > > --- /dev/null > > +++ b/lib/test_memcpy.c > > @@ -0,0 +1,265 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * Test cases for memcpy(), memmove(), and memset(). > > + */ > > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > > + > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > + > > +struct some_bytes { > > + union { > > + u8 data[32]; > > + struct { > > + u32 one; > > + u16 two; > > + u8 three; > > + /* 1 byte hole */ > > + u32 four[4]; > > + }; > > + }; > > +}; > > + > > +#define check(instance, v) do { \ > > + int i; \ > > + BUILD_BUG_ON(sizeof(instance.data) != 32); \ > > + for (i = 0; i < sizeof(instance.data); i++) { \ > > + KUNIT_ASSERT_EQ_MSG(test, instance.data[i], v, \ > > + "line %d: '%s' not initialized to 0x%02x @ %d (saw 0x%02x)\n", \ > > + __LINE__, #instance, v, i, instance.data[i]); \ > > + } \ > > +} while (0) > > + > > +#define compare(name, one, two) do { \ > > + int i; \ > > + BUILD_BUG_ON(sizeof(one) != sizeof(two)); \ > > + for (i = 0; i < sizeof(one); i++) { \ > > + KUNIT_EXPECT_EQ_MSG(test, one.data[i], two.data[i], \ > > + "line %d: %s.data[%d] (0x%02x) != %s.data[%d] (0x%02x)\n", \ > > + __LINE__, #one, i, one.data[i], #two, i, two.data[i]); \ > > + } \ > > + kunit_info(test, "ok: " TEST_OP "() " name "\n"); \ > > +} while (0) > > + > > +static void memcpy_test(struct kunit *test) > > +{ > > +#define TEST_OP "memcpy" > > + struct some_bytes control = { > > + .data = { 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, > > + 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, > > + 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, > > + 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, > > + }, > > + }; > > + struct some_bytes zero = { }; > > + struct some_bytes middle = { > > + .data = { 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, > > + 0x20, 0x20, 0x20, 0x20, 0x00, 0x00, 0x00, 0x00, > > + 0x00, 0x00, 0x00, 0x20, 0x20, 0x20, 0x20, 0x20, > > + 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, > > + }, > > + }; > > + struct some_bytes three = { > > + .data = { 0x00, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, > > + 0x20, 0x00, 0x00, 0x20, 0x20, 0x20, 0x20, 0x20, > > + 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, > > + 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, > > + }, > > + }; > > + struct some_bytes dest = { }; > > + int count; > > + u8 *ptr; > > + > > + /* Verify static initializers. */ > > + check(control, 0x20); > > + check(zero, 0); > > + compare("static initializers", dest, zero); > > + > > + /* Verify assignment. */ > > + dest = control; > > + compare("direct assignment", dest, control); > > + > > + /* Verify complete overwrite. */ > > + memcpy(dest.data, zero.data, sizeof(dest.data)); > > + compare("complete overwrite", dest, zero); > > + > > + /* Verify middle overwrite. */ > > + dest = control; > > + memcpy(dest.data + 12, zero.data, 7); > > + compare("middle overwrite", dest, middle); > > + > > + /* Verify argument side-effects aren't repeated. */ > > + dest = control; > > + ptr = dest.data; > > + count = 1; > > + memcpy(ptr++, zero.data, count++); > > + ptr += 8; > > + memcpy(ptr++, zero.data, count++); > > + compare("argument side-effects", dest, three); > > +#undef TEST_OP > > +} > > + > > +static void memmove_test(struct kunit *test) > > +{ > > +#define TEST_OP "memmove" > > + struct some_bytes control = { > > + .data = { 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, > > + 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, > > + 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, > > + 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, > > + }, > > + }; > > + struct some_bytes zero = { }; > > + struct some_bytes middle = { > > + .data = { 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, > > + 0x99, 0x99, 0x99, 0x99, 0x00, 0x00, 0x00, 0x00, > > + 0x00, 0x00, 0x00, 0x99, 0x99, 0x99, 0x99, 0x99, > > + 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, > > + }, > > + }; > > + struct some_bytes five = { > > + .data = { 0x00, 0x00, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, > > + 0x99, 0x99, 0x00, 0x00, 0x00, 0x99, 0x99, 0x99, > > + 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, > > + 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, > > + }, > > + }; > > + struct some_bytes overlap = { > > + .data = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, > > + 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, > > + 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, > > + 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, > > + }, > > + }; > > + struct some_bytes overlap_expected = { > > + .data = { 0x00, 0x01, 0x00, 0x01, 0x02, 0x03, 0x04, 0x07, > > + 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, > > + 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, > > + 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, > > + }, > > + }; > > + struct some_bytes dest = { }; > > + int count; > > + u8 *ptr; > > + > > + /* Verify static initializers. */ > > + check(control, 0x99); > > + check(zero, 0); > > + compare("static initializers", zero, dest); > > + > > + /* Verify assignment. */ > > + dest = control; > > + compare("direct assignment", dest, control); > > + > > + /* Verify complete overwrite. */ > > + memmove(dest.data, zero.data, sizeof(dest.data)); > > + compare("complete overwrite", dest, zero); > > + > > + /* Verify middle overwrite. */ > > + dest = control; > > + memmove(dest.data + 12, zero.data, 7); > > + compare("middle overwrite", dest, middle); > > + > > + /* Verify argument side-effects aren't repeated. */ > > + dest = control; > > + ptr = dest.data; > > + count = 2; > > + memmove(ptr++, zero.data, count++); > > + ptr += 9; > > + memmove(ptr++, zero.data, count++); > > + compare("argument side-effects", dest, five); > > + > > + /* Verify overlapping overwrite is correct. */ > > + ptr = &overlap.data[2]; > > + memmove(ptr, overlap.data, 5); > > + compare("overlapping write", overlap, overlap_expected); > > +#undef TEST_OP > > +} > > + > > +static void memset_test(struct kunit *test) > > +{ > > +#define TEST_OP "memset" > > + struct some_bytes control = { > > + .data = { 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, > > + 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, > > + 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, > > + 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, > > + }, > > + }; > > + struct some_bytes complete = { > > + .data = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, > > + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, > > + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, > > + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, > > + }, > > + }; > > + struct some_bytes middle = { > > + .data = { 0x30, 0x30, 0x30, 0x30, 0x31, 0x31, 0x31, 0x31, > > + 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, > > + 0x31, 0x31, 0x31, 0x31, 0x30, 0x30, 0x30, 0x30, > > + 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, > > + }, > > + }; > > + struct some_bytes three = { > > + .data = { 0x60, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, > > + 0x30, 0x61, 0x61, 0x30, 0x30, 0x30, 0x30, 0x30, > > + 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, > > + 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, > > + }, > > + }; > > + struct some_bytes dest = { }; > > + int count, value; > > + u8 *ptr; > > + > > + /* Verify static initializers. */ > > + check(control, 0x30); > > + check(dest, 0); > > + > > + /* Verify assignment. */ > > + dest = control; > > + compare("direct assignment", dest, control); > > + > > + /* Verify complete overwrite. */ > > + memset(dest.data, 0xff, sizeof(dest.data)); > > + compare("complete overwrite", dest, complete); > > + > > + /* Verify middle overwrite. */ > > + dest = control; > > + memset(dest.data + 4, 0x31, 16); > > + compare("middle overwrite", dest, middle); > > + > > + /* Verify argument side-effects aren't repeated. */ > > + dest = control; > > + ptr = dest.data; > > + value = 0x60; > > + count = 1; > > + memset(ptr++, value++, count++); > > + ptr += 8; > > + memset(ptr++, value++, count++); > > + compare("argument side-effects", dest, three); > > +#undef TEST_OP > > +} > > + > > +static struct kunit_case memcpy_test_cases[] = { > > + KUNIT_CASE(memset_test), > > + KUNIT_CASE(memcpy_test), > > + KUNIT_CASE(memmove_test), > > + {} > > +}; > > + > > +static struct kunit_suite memcpy_test_suite = { > > + .name = "memcpy-test", > > It may be better to just name the suite "memcpy", since -- by > definition -- it's a test if it's a KUnit test suite. Sounds good. I will adjust this. > > > + .test_cases = memcpy_test_cases, > > +}; > > + > > +kunit_test_suite(memcpy_test_suite); > > + > > +MODULE_LICENSE("GPL"); > > -- > > 2.30.2 > > Thanks! -Kees -- Kees Cook