| Message ID | 20220504014440.3697851-4-keescook@chromium.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Introduce flexible array struct memcpy() helpers | expand |
On Wed, May 4, 2022 at 9:47 AM Kees Cook <keescook@chromium.org> wrote: > > Add tests for the new flexible array structure helpers. These can be run > with: > > make ARCH=um mrproper > ./tools/testing/kunit/kunit.py config Nit: it shouldn't be necessary to run kunit.py config separately: kunit.py run will configure the kernel if necessary. > ./tools/testing/kunit/kunit.py run flex_array > > Cc: David Gow <davidgow@google.com> > Cc: kunit-dev@googlegroups.com > Signed-off-by: Kees Cook <keescook@chromium.org> > --- This looks pretty good to me: it certainly worked on the different setups I tried (um, x86_64, x86_64+KASAN). A few minor nitpicks inline, mostly around minor config-y things, or things which weren't totally clear on my first read-through. Hopefully one day, with the various stubbing features or something similar, we'll be able to check against allocation failures in flex_dup(), too, but otherwise nothing seems too obviously missing. Reviewed-by: David Gow <davidgow@google.com> -- David > lib/Kconfig.debug | 12 +- > lib/Makefile | 1 + > lib/flex_array_kunit.c | 523 +++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 531 insertions(+), 5 deletions(-) > create mode 100644 lib/flex_array_kunit.c > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 9077bb38bc93..8bae6b169c50 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -2551,11 +2551,6 @@ config OVERFLOW_KUNIT_TEST > Builds unit tests for the check_*_overflow(), size_*(), allocation, and > related 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. > - Nit: while I'm not against removing some of this boilerplate, is it better suited for a separate commit? > config STACKINIT_KUNIT_TEST > tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS > depends on KUNIT > @@ -2567,6 +2562,13 @@ config STACKINIT_KUNIT_TEST > CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, > or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. > > +config FLEX_ARRAY_KUNIT_TEST > + tristate "Test flex_*() family of helper functions at runtime" if !KUNIT_ALL_TESTS > + depends on KUNIT > + default KUNIT_ALL_TESTS > + help > + Builds unit tests for flexible array copy helper functions. > + Nit: checkpatch warns that the description here may be insufficient: WARNING: please write a help paragraph that fully describes the config symbol > config TEST_UDELAY > tristate "udelay test driver" > help > diff --git a/lib/Makefile b/lib/Makefile > index 6b9ffc1bd1ee..9884318db330 100644 > --- a/lib/Makefile > +++ b/lib/Makefile > @@ -366,6 +366,7 @@ obj-$(CONFIG_MEMCPY_KUNIT_TEST) += memcpy_kunit.o > obj-$(CONFIG_OVERFLOW_KUNIT_TEST) += overflow_kunit.o > CFLAGS_stackinit_kunit.o += $(call cc-disable-warning, switch-unreachable) > obj-$(CONFIG_STACKINIT_KUNIT_TEST) += stackinit_kunit.o > +obj-$(CONFIG_FLEX_ARRAY_KUNIT_TEST) += flex_array_kunit.o > > obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) += devmem_is_allowed.o > > diff --git a/lib/flex_array_kunit.c b/lib/flex_array_kunit.c > new file mode 100644 > index 000000000000..48bee88945b4 > --- /dev/null > +++ b/lib/flex_array_kunit.c > @@ -0,0 +1,523 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Test cases for flex_*() array manipulation helpers. > + */ > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > + > +#include <kunit/test.h> > +#include <linux/device.h> > +#include <linux/init.h> > +#include <linux/kernel.h> > +#include <linux/flex_array.h> > + > +#define COMPARE_STRUCTS(STRUCT_A, STRUCT_B) do { \ > + STRUCT_A *ptr_A; \ > + STRUCT_B *ptr_B; \ > + int rc; \ > + size_t size_A, size_B; \ > + \ > + /* matching types for flex array elements and count */ \ > + KUNIT_EXPECT_EQ(test, sizeof(*ptr_A), sizeof(*ptr_B)); \ > + KUNIT_EXPECT_TRUE(test, __same_type(*ptr_A->data, \ > + *ptr_B->__flex_array_elements)); \ > + KUNIT_EXPECT_TRUE(test, __same_type(ptr_A->datalen, \ > + ptr_B->__flex_array_elements_count)); \ > + KUNIT_EXPECT_EQ(test, sizeof(*ptr_A->data), \ > + sizeof(*ptr_B->__flex_array_elements)); \ > + KUNIT_EXPECT_EQ(test, offsetof(typeof(*ptr_A), data), \ > + offsetof(typeof(*ptr_B), \ > + __flex_array_elements)); \ > + KUNIT_EXPECT_EQ(test, offsetof(typeof(*ptr_A), datalen), \ > + offsetof(typeof(*ptr_B), \ > + __flex_array_elements_count)); \ > + \ > + /* struct_size() vs __fas_bytes() */ \ > + size_A = struct_size(ptr_A, data, 13); \ > + rc = __fas_bytes(ptr_B, __flex_array_elements, \ > + __flex_array_elements_count, 13, &size_B); \ > + KUNIT_EXPECT_EQ(test, rc, 0); \ > + KUNIT_EXPECT_EQ(test, size_A, size_B); \ > + \ > + /* flex_array_size() vs __fas_elements_bytes() */ \ > + size_A = flex_array_size(ptr_A, data, 13); \ > + rc = __fas_elements_bytes(ptr_B, __flex_array_elements, \ > + __flex_array_elements_count, 13, &size_B); \ > + KUNIT_EXPECT_EQ(test, rc, 0); \ > + KUNIT_EXPECT_EQ(test, size_A, size_B); \ > + \ > + KUNIT_EXPECT_EQ(test, sizeof(*ptr_A) + size_A, \ > + offsetof(typeof(*ptr_A), data) + \ > + (sizeof(*ptr_A->data) * 13)); \ > + KUNIT_EXPECT_EQ(test, sizeof(*ptr_B) + size_B, \ > + offsetof(typeof(*ptr_B), \ > + __flex_array_elements) + \ > + (sizeof(*ptr_B->__flex_array_elements) * \ > + 13)); \ > +} while (0) > + > +struct normal { > + size_t datalen; > + u32 data[]; > +}; > + > +struct decl_normal { > + DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(size_t, datalen); > + DECLARE_FLEX_ARRAY_ELEMENTS(u32, data); > +}; > + > +struct aligned { > + unsigned short datalen; > + char data[] __aligned(__alignof__(u64)); > +}; > + > +struct decl_aligned { > + DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(unsigned short, datalen); > + DECLARE_FLEX_ARRAY_ELEMENTS(char, data) __aligned(__alignof__(u64)); > +}; > + > +static void struct_test(struct kunit *test) > +{ > + COMPARE_STRUCTS(struct normal, struct decl_normal); > + COMPARE_STRUCTS(struct aligned, struct decl_aligned); > +} If I understand it, the purpose of this is to ensure that structs both with and without the flexible array declaration have the same memory layout? If so, any chance of a comment briefly stating that's the purpose (or renaming this test struct_layout_test())? Also, would it make sense to do the same with the struct with internal padding below? > + > +/* Flexible array structure with internal padding. */ > +struct flex_cpy_obj { > + DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(u8, count); > + unsigned long empty; > + char induce_padding; > + /* padding ends up here */ > + unsigned long after_padding; > + DECLARE_FLEX_ARRAY_ELEMENTS(u32, flex); > +}; > + > +/* Encapsulating flexible array structure. */ > +struct flex_dup_obj { > + unsigned long flags; > + int junk; > + struct flex_cpy_obj fas; > +}; > + > +/* Flexible array struct of only bytes. */ > +struct tiny_flex { > + DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(u8, count); > + DECLARE_FLEX_ARRAY_ELEMENTS(u8, byte_array); > +}; > + > +#define CHECK_COPY(ptr) do { \ > + typeof(*(ptr)) *_cc_dst = (ptr); \ > + KUNIT_EXPECT_EQ(test, _cc_dst->induce_padding, 0); \ > + memcpy(&padding, &_cc_dst->induce_padding + sizeof(_cc_dst->induce_padding), \ > + sizeof(padding)); \ > + /* Padding should be zero too. */ \ > + KUNIT_EXPECT_EQ(test, padding, 0); \ > + KUNIT_EXPECT_EQ(test, src->count, _cc_dst->count); \ > + KUNIT_EXPECT_EQ(test, _cc_dst->count, TEST_TARGET); \ > + for (i = 0; i < _cc_dst->count - 1; i++) { \ > + /* 'A' is 0x41, and here repeated in a u32. */ \ Would it be simpler to just note that the magic value is 0x41, rather than have it be the character 'A'? > + KUNIT_EXPECT_EQ(test, _cc_dst->flex[i], 0x41414141); \ > + } \ > + /* Last item should be different. */ \ > + KUNIT_EXPECT_EQ(test, _cc_dst->flex[_cc_dst->count - 1], 0x14141414); \ > +} while (0) > + > +/* Test copying from one flexible array struct into another. */ > +static void flex_cpy_test(struct kunit *test) > +{ > +#define TEST_BOUNDS 13 > +#define TEST_TARGET 12 > +#define TEST_SMALL 10 > + struct flex_cpy_obj *src, *dst; > + unsigned long padding; > + int i, rc; > + > + /* Prepare open-coded source. */ > + src = kzalloc(struct_size(src, flex, TEST_BOUNDS), GFP_KERNEL); > + src->count = TEST_BOUNDS; > + memset(src->flex, 'A', flex_array_size(src, flex, TEST_BOUNDS)); As above, it's possibly nicer to just state 0x41 here, rather than 'A', since all we're doing is checking against a hex value. > + src->flex[src->count - 2] = 0x14141414; > + src->flex[src->count - 1] = 0x24242424; > + > + /* Prepare open-coded destination, alloc only. */ > + dst = kzalloc(struct_size(src, flex, TEST_BOUNDS), GFP_KERNEL); > + /* Pre-fill with 0xFE marker. */ > + memset(dst, 0xFE, struct_size(src, flex, TEST_BOUNDS)); > + /* Pretend we're 1 element smaller. */ > + dst->count = TEST_TARGET; > + > + /* Pretend to match the target destination size. */ > + src->count = TEST_TARGET; > + > + rc = flex_cpy(dst, src); > + KUNIT_EXPECT_EQ(test, rc, 0); > + CHECK_COPY(dst); > + /* Item past last copied item is unchanged from initial memset. */ > + KUNIT_EXPECT_EQ(test, dst->flex[dst->count], 0xFEFEFEFE); > + > + /* Now trip overflow, and verify we didn't clobber beyond end. */ > + src->count = TEST_BOUNDS; > + rc = flex_cpy(dst, src); > + KUNIT_EXPECT_EQ(test, rc, -E2BIG); > + /* Item past last copied item is unchanged from initial memset. */ > + KUNIT_EXPECT_EQ(test, dst->flex[dst->count], 0xFEFEFEFE); > + > + /* Reset destination contents. */ > + memset(dst, 0xFD, struct_size(src, flex, TEST_BOUNDS)); > + dst->count = TEST_TARGET; > + > + /* Copy less than max. */ > + src->count = TEST_SMALL; > + rc = flex_cpy(dst, src); > + KUNIT_EXPECT_EQ(test, rc, 0); > + /* Verify count was adjusted. */ > + KUNIT_EXPECT_EQ(test, dst->count, TEST_SMALL); > + /* Verify element beyond src size was wiped. */ > + KUNIT_EXPECT_EQ(test, dst->flex[TEST_SMALL], 0); > + /* Verify element beyond original dst size was untouched. */ > + KUNIT_EXPECT_EQ(test, dst->flex[TEST_TARGET], 0xFDFDFDFD); > + > + kfree(dst); > + kfree(src); > +#undef TEST_BOUNDS > +#undef TEST_TARGET > +#undef TEST_SMALL > +} > + > +static void flex_dup_test(struct kunit *test) > +{ > +#define TEST_TARGET 12 > + struct flex_cpy_obj *src, *dst = NULL, **null = NULL; > + struct flex_dup_obj *encap = NULL; > + unsigned long padding; > + int i, rc; > + > + /* Prepare open-coded source. */ > + src = kzalloc(struct_size(src, flex, TEST_TARGET), GFP_KERNEL); > + src->count = TEST_TARGET; > + memset(src->flex, 'A', flex_array_size(src, flex, TEST_TARGET)); > + src->flex[src->count - 1] = 0x14141414; > + > + /* Reject NULL @alloc. */ > + rc = flex_dup(null, src, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, -EINVAL); > + > + /* Check good copy. */ > + rc = flex_dup(&dst, src, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, 0); > + KUNIT_ASSERT_TRUE(test, dst != NULL); > + CHECK_COPY(dst); > + > + /* Reject non-NULL *@alloc. */ > + rc = flex_dup(&dst, src, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, -EINVAL); > + > + kfree(dst); > + > + /* Check good encap copy. */ > + rc = __flex_dup(&encap, .fas, src, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, 0); > + KUNIT_ASSERT_TRUE(test, dst != NULL); > + CHECK_COPY(&encap->fas); > + /* Check that items external to "fas" are zero. */ > + KUNIT_EXPECT_EQ(test, encap->flags, 0); > + KUNIT_EXPECT_EQ(test, encap->junk, 0); > + kfree(encap); > +#undef MAGIC_WORD MAGIC_WORD isn't defined (or used) for flux_dup_test? Is it worth using it (or something similar) for the 'A' / 0x14141414 and the CHECK_COPY() macro? > +#undef TEST_TARGET > +} > + > +static void mem_to_flex_test(struct kunit *test) > +{ > +#define TEST_TARGET 9 > +#define TEST_MAX U8_MAX > +#define MAGIC_WORD 0x03030303 > + u8 magic_byte = MAGIC_WORD & 0xff; > + struct flex_cpy_obj *dst; > + size_t big = (size_t)INT_MAX + 1; > + char small[] = "Hello"; > + char *src; > + u32 src_len; > + int rc; > + > + /* Open coded allocations, 1 larger than actually used. */ > + src_len = flex_array_size(dst, flex, TEST_MAX + 1); > + src = kzalloc(src_len, GFP_KERNEL); > + dst = kzalloc(struct_size(dst, flex, TEST_MAX + 1), GFP_KERNEL); > + dst->count = TEST_TARGET; > + > + /* Fill source. */ > + memset(src, magic_byte, src_len); > + > + /* Short copy is fine. */ > + KUNIT_EXPECT_EQ(test, dst->flex[0], 0); > + KUNIT_EXPECT_EQ(test, dst->flex[1], 0); > + rc = mem_to_flex(dst, src, 1); > + KUNIT_EXPECT_EQ(test, rc, 0); > + KUNIT_EXPECT_EQ(test, dst->count, 1); > + KUNIT_EXPECT_EQ(test, dst->after_padding, 0); > + KUNIT_EXPECT_EQ(test, dst->flex[0], MAGIC_WORD); > + KUNIT_EXPECT_EQ(test, dst->flex[1], 0); > + dst->count = TEST_TARGET; > + > + /* Reject negative elements count. */ > + rc = mem_to_flex(dst, small, -1); > + KUNIT_EXPECT_EQ(test, rc, -E2BIG); > + /* Make sure dst is unchanged. */ > + KUNIT_EXPECT_EQ(test, dst->flex[0], MAGIC_WORD); > + KUNIT_EXPECT_EQ(test, dst->flex[1], 0); > + > + /* Reject compile-time read overflow. */ > + rc = mem_to_flex(dst, small, 20); > + KUNIT_EXPECT_EQ(test, rc, -E2BIG); > + /* Make sure dst is unchanged. */ > + KUNIT_EXPECT_EQ(test, dst->flex[0], MAGIC_WORD); > + KUNIT_EXPECT_EQ(test, dst->flex[1], 0); > + > + /* Reject giant buffer source. */ > + rc = mem_to_flex(dst, small, big); > + KUNIT_EXPECT_EQ(test, rc, -E2BIG); > + /* Make sure dst is unchanged. */ > + KUNIT_EXPECT_EQ(test, dst->flex[0], MAGIC_WORD); > + KUNIT_EXPECT_EQ(test, dst->flex[1], 0); > + > + /* Copy beyond storage size is rejected. */ > + dst->count = TEST_MAX; > + KUNIT_EXPECT_EQ(test, dst->flex[TEST_MAX - 1], 0); > + KUNIT_EXPECT_EQ(test, dst->flex[TEST_MAX], 0); > + rc = mem_to_flex(dst, src, TEST_MAX + 1); > + KUNIT_EXPECT_EQ(test, rc, -E2BIG); > + /* Make sure dst is unchanged. */ > + KUNIT_EXPECT_EQ(test, dst->flex[0], MAGIC_WORD); > + KUNIT_EXPECT_EQ(test, dst->flex[1], 0); > + > + kfree(dst); > + kfree(src); > +#undef MAGIC_WORD > +#undef TEST_MAX > +#undef TEST_TARGET > +} > + > +static void mem_to_flex_dup_test(struct kunit *test) > +{ > +#define ELEMENTS_COUNT 259 > +#define MAGIC_WORD 0xABABABAB > + u8 magic_byte = MAGIC_WORD & 0xff; > + struct flex_dup_obj *obj = NULL; > + struct tiny_flex *tiny = NULL, **null = NULL; > + size_t src_len, count, big = (size_t)INT_MAX + 1; > + char small[] = "Hello"; > + u8 *src; > + int rc; > + > + src_len = struct_size(tiny, byte_array, ELEMENTS_COUNT); > + src = kzalloc(src_len, GFP_KERNEL); > + KUNIT_ASSERT_TRUE(test, src != NULL); > + /* Fill with bytes. */ > + memset(src, magic_byte, src_len); > + KUNIT_EXPECT_EQ(test, src[0], magic_byte); > + KUNIT_EXPECT_EQ(test, src[src_len / 2], magic_byte); > + KUNIT_EXPECT_EQ(test, src[src_len - 1], magic_byte); > + > + /* Reject storage exceeding elements_count type. */ > + count = ELEMENTS_COUNT; > + rc = mem_to_flex_dup(&tiny, src, count, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, -E2BIG); > + KUNIT_EXPECT_TRUE(test, tiny == NULL); > + > + /* Reject negative elements count. */ > + rc = mem_to_flex_dup(&tiny, src, -1, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, -E2BIG); > + KUNIT_EXPECT_TRUE(test, tiny == NULL); > + > + /* Reject compile-time read overflow. */ > + rc = mem_to_flex_dup(&tiny, small, 20, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, -E2BIG); > + KUNIT_EXPECT_TRUE(test, tiny == NULL); > + > + /* Reject giant buffer source. */ > + rc = mem_to_flex_dup(&tiny, small, big, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, -E2BIG); > + KUNIT_EXPECT_TRUE(test, tiny == NULL); > + > + /* Reject NULL @alloc. */ > + rc = mem_to_flex_dup(null, src, count, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, -EINVAL); > + > + /* Allow reasonable count.*/ > + count = ELEMENTS_COUNT / 2; > + rc = mem_to_flex_dup(&tiny, src, count, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, 0); > + KUNIT_ASSERT_TRUE(test, tiny != NULL); > + /* Spot check the copy happened. */ > + KUNIT_EXPECT_EQ(test, tiny->count, count); > + KUNIT_EXPECT_EQ(test, tiny->byte_array[0], magic_byte); > + KUNIT_EXPECT_EQ(test, tiny->byte_array[count / 2], magic_byte); > + KUNIT_EXPECT_EQ(test, tiny->byte_array[count - 1], magic_byte); > + > + /* Reject non-NULL *@alloc. */ > + rc = mem_to_flex_dup(&tiny, src, count, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, -EINVAL); > + kfree(tiny); > + > + /* Works with encapsulation too. */ > + count = ELEMENTS_COUNT / 10; > + rc = __mem_to_flex_dup(&obj, .fas, src, count, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, 0); > + KUNIT_ASSERT_TRUE(test, obj != NULL); > + /* Spot check the copy happened. */ > + KUNIT_EXPECT_EQ(test, obj->fas.count, count); > + KUNIT_EXPECT_EQ(test, obj->fas.after_padding, 0); > + KUNIT_EXPECT_EQ(test, obj->fas.flex[0], MAGIC_WORD); > + KUNIT_EXPECT_EQ(test, obj->fas.flex[count / 2], MAGIC_WORD); > + KUNIT_EXPECT_EQ(test, obj->fas.flex[count - 1], MAGIC_WORD); > + /* Check members before flexible array struct are zero. */ > + KUNIT_EXPECT_EQ(test, obj->flags, 0); > + KUNIT_EXPECT_EQ(test, obj->junk, 0); > + kfree(obj); > +#undef MAGIC_WORD > +#undef ELEMENTS_COUNT > +} > + > +static void flex_to_mem_test(struct kunit *test) > +{ > +#define ELEMENTS_COUNT 200 > +#define MAGIC_WORD 0xF1F2F3F4 > + struct flex_cpy_obj *src; > + typeof(*src->flex) *cast; > + size_t src_len = struct_size(src, flex, ELEMENTS_COUNT); > + size_t copy_len = flex_array_size(src, flex, ELEMENTS_COUNT); > + int i, rc; > + size_t bytes = 0; > + u8 too_small; > + u8 *dst; > + > + /* Create a filled flexible array struct. */ > + src = kzalloc(src_len, GFP_KERNEL); > + KUNIT_ASSERT_TRUE(test, src != NULL); > + src->count = ELEMENTS_COUNT; > + src->after_padding = 13; > + for (i = 0; i < ELEMENTS_COUNT; i++) > + src->flex[i] = MAGIC_WORD; > + > + /* Over-allocate space to do past-src_len checking. */ > + dst = kzalloc(src_len * 2, GFP_KERNEL); > + KUNIT_ASSERT_TRUE(test, dst != NULL); > + cast = (void *)dst; > + > + /* Fail if dst is too small. */ > + rc = flex_to_mem(dst, copy_len - 1, src, &bytes); > + KUNIT_EXPECT_EQ(test, rc, -E2BIG); > + /* Make sure nothing was copied. */ > + KUNIT_EXPECT_EQ(test, bytes, 0); > + KUNIT_EXPECT_EQ(test, cast[0], 0); > + > + /* Fail if type too small to hold size of copy. */ > + KUNIT_EXPECT_GT(test, copy_len, type_max(typeof(too_small))); > + rc = flex_to_mem(dst, copy_len, src, &too_small); > + KUNIT_EXPECT_EQ(test, rc, -E2BIG); > + /* Make sure nothing was copied. */ > + KUNIT_EXPECT_EQ(test, bytes, 0); > + KUNIT_EXPECT_EQ(test, cast[0], 0); > + > + /* Check good copy. */ > + rc = flex_to_mem(dst, copy_len, src, &bytes); > + KUNIT_EXPECT_EQ(test, rc, 0); > + KUNIT_EXPECT_EQ(test, bytes, copy_len); > + /* Spot check the copy */ > + KUNIT_EXPECT_EQ(test, cast[0], MAGIC_WORD); > + KUNIT_EXPECT_EQ(test, cast[ELEMENTS_COUNT / 2], MAGIC_WORD); > + KUNIT_EXPECT_EQ(test, cast[ELEMENTS_COUNT - 1], MAGIC_WORD); > + /* Make sure nothing was written after last element. */ > + KUNIT_EXPECT_EQ(test, cast[ELEMENTS_COUNT], 0); > + > + kfree(dst); > + kfree(src); > +#undef MAGIC_WORD > +#undef ELEMENTS_COUNT > +} > + > +static void flex_to_mem_dup_test(struct kunit *test) > +{ > +#define ELEMENTS_COUNT 210 > +#define MAGIC_WORD 0xF0F1F2F3 > + struct flex_dup_obj *obj, **null = NULL; > + struct flex_cpy_obj *src; > + typeof(*src->flex) *cast; > + size_t obj_len = struct_size(obj, fas.flex, ELEMENTS_COUNT); > + size_t src_len = struct_size(src, flex, ELEMENTS_COUNT); > + size_t copy_len = flex_array_size(src, flex, ELEMENTS_COUNT); > + int i, rc; > + size_t bytes = 0; > + u8 too_small = 0; > + u8 *dst = NULL; > + > + /* Create a filled flexible array struct. */ > + obj = kzalloc(obj_len, GFP_KERNEL); > + KUNIT_ASSERT_TRUE(test, obj != NULL); > + obj->fas.count = ELEMENTS_COUNT; > + obj->fas.after_padding = 13; > + for (i = 0; i < ELEMENTS_COUNT; i++) > + obj->fas.flex[i] = MAGIC_WORD; > + src = &obj->fas; > + > + /* Fail if type too small to hold size of copy. */ > + KUNIT_EXPECT_GT(test, src_len, type_max(typeof(too_small))); > + rc = flex_to_mem_dup(&dst, &too_small, src, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, -E2BIG); > + KUNIT_EXPECT_TRUE(test, dst == NULL); > + KUNIT_EXPECT_EQ(test, too_small, 0); > + > + /* Fail if @alloc_size is NULL. */ > + KUNIT_EXPECT_TRUE(test, dst == NULL); > + rc = flex_to_mem_dup(&dst, dst, src, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, -EINVAL); > + KUNIT_EXPECT_TRUE(test, dst == NULL); > + > + /* Fail if @alloc is NULL. */ > + rc = flex_to_mem_dup(null, &bytes, src, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, -EINVAL); > + KUNIT_EXPECT_TRUE(test, dst == NULL); > + KUNIT_EXPECT_EQ(test, bytes, 0); > + > + /* Check good copy. */ > + rc = flex_to_mem_dup(&dst, &bytes, src, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, 0); > + KUNIT_EXPECT_TRUE(test, dst != NULL); > + KUNIT_EXPECT_EQ(test, bytes, copy_len); > + cast = (void *)dst; > + /* Spot check the copy */ > + KUNIT_EXPECT_EQ(test, cast[0], MAGIC_WORD); > + KUNIT_EXPECT_EQ(test, cast[ELEMENTS_COUNT / 2], MAGIC_WORD); > + KUNIT_EXPECT_EQ(test, cast[ELEMENTS_COUNT - 1], MAGIC_WORD); > + > + /* Fail if *@alloc is non-NULL. */ > + bytes = 0; > + rc = flex_to_mem_dup(&dst, &bytes, src, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, -EINVAL); > + KUNIT_EXPECT_EQ(test, bytes, 0); > + > + kfree(dst); > + kfree(obj); > +#undef MAGIC_WORD > +#undef ELEMENTS_COUNT > +} > + > +static struct kunit_case flex_array_test_cases[] = { > + KUNIT_CASE(struct_test), > + KUNIT_CASE(flex_cpy_test), > + KUNIT_CASE(flex_dup_test), > + KUNIT_CASE(mem_to_flex_test), > + KUNIT_CASE(mem_to_flex_dup_test), > + KUNIT_CASE(flex_to_mem_test), > + KUNIT_CASE(flex_to_mem_dup_test), > + {} > +}; > + > +static struct kunit_suite flex_array_test_suite = { > + .name = "flex_array", > + .test_cases = flex_array_test_cases, > +}; > + > +kunit_test_suite(flex_array_test_suite); > + > +MODULE_LICENSE("GPL"); > -- > 2.32.0 >
On Wed, May 04, 2022 at 11:00:38AM +0800, David Gow wrote: > On Wed, May 4, 2022 at 9:47 AM Kees Cook <keescook@chromium.org> wrote: > > > > Add tests for the new flexible array structure helpers. These can be run > > with: > > > > make ARCH=um mrproper > > ./tools/testing/kunit/kunit.py config > > Nit: it shouldn't be necessary to run kunit.py config separately: > kunit.py run will configure the kernel if necessary. Ah yes, I think you mentioned this before. I'll adjust the commit log. > > > ./tools/testing/kunit/kunit.py run flex_array > > > > Cc: David Gow <davidgow@google.com> > > Cc: kunit-dev@googlegroups.com > > Signed-off-by: Kees Cook <keescook@chromium.org> > > --- > > This looks pretty good to me: it certainly worked on the different > setups I tried (um, x86_64, x86_64+KASAN). > > A few minor nitpicks inline, mostly around minor config-y things, or > things which weren't totally clear on my first read-through. > > Hopefully one day, with the various stubbing features or something > similar, we'll be able to check against allocation failures in > flex_dup(), too, but otherwise nothing seems too obviously missing. > > Reviewed-by: David Gow <davidgow@google.com> Great; thanks for the review and testing! > > -- David > > > lib/Kconfig.debug | 12 +- > > lib/Makefile | 1 + > > lib/flex_array_kunit.c | 523 +++++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 531 insertions(+), 5 deletions(-) > > create mode 100644 lib/flex_array_kunit.c > > > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > > index 9077bb38bc93..8bae6b169c50 100644 > > --- a/lib/Kconfig.debug > > +++ b/lib/Kconfig.debug > > @@ -2551,11 +2551,6 @@ config OVERFLOW_KUNIT_TEST > > Builds unit tests for the check_*_overflow(), size_*(), allocation, and > > related 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. > > - > > Nit: while I'm not against removing some of this boilerplate, is it > better suited for a separate commit? Make sense, yes. I'll drop this for now. > > > config STACKINIT_KUNIT_TEST > > tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS > > depends on KUNIT > > @@ -2567,6 +2562,13 @@ config STACKINIT_KUNIT_TEST > > CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, > > or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. > > > > +config FLEX_ARRAY_KUNIT_TEST > > + tristate "Test flex_*() family of helper functions at runtime" if !KUNIT_ALL_TESTS > > + depends on KUNIT > > + default KUNIT_ALL_TESTS > > + help > > + Builds unit tests for flexible array copy helper functions. > > + > > Nit: checkpatch warns that the description here may be insufficient: > WARNING: please write a help paragraph that fully describes the config symbol Yeah, I don't know anything to put here that isn't just more boilerplate, so I'm choosing to ignore this for now. :) > > [...] > > +struct normal { > > + size_t datalen; > > + u32 data[]; > > +}; > > + > > +struct decl_normal { > > + DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(size_t, datalen); > > + DECLARE_FLEX_ARRAY_ELEMENTS(u32, data); > > +}; > > + > > +struct aligned { > > + unsigned short datalen; > > + char data[] __aligned(__alignof__(u64)); > > +}; > > + > > +struct decl_aligned { > > + DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(unsigned short, datalen); > > + DECLARE_FLEX_ARRAY_ELEMENTS(char, data) __aligned(__alignof__(u64)); > > +}; > > + > > +static void struct_test(struct kunit *test) > > +{ > > + COMPARE_STRUCTS(struct normal, struct decl_normal); > > + COMPARE_STRUCTS(struct aligned, struct decl_aligned); > > +} > > If I understand it, the purpose of this is to ensure that structs both > with and without the flexible array declaration have the same memory > layout? > > If so, any chance of a comment briefly stating that's the purpose (or > renaming this test struct_layout_test())? Yeah, good idea; I'll improve the naming. > > Also, would it make sense to do the same with the struct with internal > padding below? Heh, yes, good point! :) > [...] > > +#define CHECK_COPY(ptr) do { \ > > + typeof(*(ptr)) *_cc_dst = (ptr); \ > > + KUNIT_EXPECT_EQ(test, _cc_dst->induce_padding, 0); \ > > + memcpy(&padding, &_cc_dst->induce_padding + sizeof(_cc_dst->induce_padding), \ > > + sizeof(padding)); \ > > + /* Padding should be zero too. */ \ > > + KUNIT_EXPECT_EQ(test, padding, 0); \ > > + KUNIT_EXPECT_EQ(test, src->count, _cc_dst->count); \ > > + KUNIT_EXPECT_EQ(test, _cc_dst->count, TEST_TARGET); \ > > + for (i = 0; i < _cc_dst->count - 1; i++) { \ > > + /* 'A' is 0x41, and here repeated in a u32. */ \ > > Would it be simpler to just note that the magic value is 0x41, rather > than have it be the character 'A'? Yeah, now fixed. > [...] > > + CHECK_COPY(&encap->fas); > > + /* Check that items external to "fas" are zero. */ > > + KUNIT_EXPECT_EQ(test, encap->flags, 0); > > + KUNIT_EXPECT_EQ(test, encap->junk, 0); > > + kfree(encap); > > +#undef MAGIC_WORD > > MAGIC_WORD isn't defined (or used) for flux_dup_test? Is it worth > using it (or something similar) for the 'A' / 0x14141414 and the > CHECK_COPY() macro? Oops, yes. Fixed. Thanks again! -Kees
On Tue, May 3, 2022 at 8:47 PM Kees Cook <keescook@chromium.org> wrote: > +#define COMPARE_STRUCTS(STRUCT_A, STRUCT_B) do { \ > + STRUCT_A *ptr_A; \ > + STRUCT_B *ptr_B; \ > + int rc; \ > + size_t size_A, size_B; \ > + \ > + /* matching types for flex array elements and count */ \ > + KUNIT_EXPECT_EQ(test, sizeof(*ptr_A), sizeof(*ptr_B)); \ > + KUNIT_EXPECT_TRUE(test, __same_type(*ptr_A->data, \ > + *ptr_B->__flex_array_elements)); \ Leaving some minor suggestions to go along with David's comments. Should we make these KUNIT_ASSERT_.* instead? I assume if we have a type-mismatch, then we should bail out instead of continuing to produce more error messages. > + KUNIT_EXPECT_TRUE(test, __same_type(ptr_A->datalen, \ > + ptr_B->__flex_array_elements_count)); \ > + KUNIT_EXPECT_EQ(test, sizeof(*ptr_A->data), \ > + sizeof(*ptr_B->__flex_array_elements)); \ > + KUNIT_EXPECT_EQ(test, offsetof(typeof(*ptr_A), data), \ > + offsetof(typeof(*ptr_B), \ > + __flex_array_elements)); \ > + KUNIT_EXPECT_EQ(test, offsetof(typeof(*ptr_A), datalen), \ > + offsetof(typeof(*ptr_B), \ > + __flex_array_elements_count)); \ > + \ > + /* struct_size() vs __fas_bytes() */ \ > + size_A = struct_size(ptr_A, data, 13); \ > + rc = __fas_bytes(ptr_B, __flex_array_elements, \ > + __flex_array_elements_count, 13, &size_B); \ > + KUNIT_EXPECT_EQ(test, rc, 0); \ Hmm, what do you think about inlining the call/dropping rc? i.e. something like KUNIT_EXPECT_EQ(test, 0, __fas_bytes(ptr_B, __flex_array_elements, \ __flex_array_elements_count, 13, &size_B)); That would give a slightly clearer error message on failure. Otherwise the user only really gets a line number to try and start to understand what went wrong. > + > +#define CHECK_COPY(ptr) do { \ > + typeof(*(ptr)) *_cc_dst = (ptr); \ > + KUNIT_EXPECT_EQ(test, _cc_dst->induce_padding, 0); \ > + memcpy(&padding, &_cc_dst->induce_padding + sizeof(_cc_dst->induce_padding), \ > + sizeof(padding)); \ > + /* Padding should be zero too. */ \ > + KUNIT_EXPECT_EQ(test, padding, 0); \ > + KUNIT_EXPECT_EQ(test, src->count, _cc_dst->count); \ This also seems like a good place to use ASSERT instead of EXPECT. > + KUNIT_EXPECT_EQ(test, _cc_dst->count, TEST_TARGET); \ > + for (i = 0; i < _cc_dst->count - 1; i++) { \ > + /* 'A' is 0x41, and here repeated in a u32. */ \ > + KUNIT_EXPECT_EQ(test, _cc_dst->flex[i], 0x41414141); \ > + } \ > + /* Last item should be different. */ \ > + KUNIT_EXPECT_EQ(test, _cc_dst->flex[_cc_dst->count - 1], 0x14141414); \ > +} while (0) > + > +/* Test copying from one flexible array struct into another. */ > +static void flex_cpy_test(struct kunit *test) > +{ > +#define TEST_BOUNDS 13 > +#define TEST_TARGET 12 > +#define TEST_SMALL 10 > + struct flex_cpy_obj *src, *dst; > + unsigned long padding; > + int i, rc; > + > + /* Prepare open-coded source. */ > + src = kzalloc(struct_size(src, flex, TEST_BOUNDS), GFP_KERNEL); Looks like we could use kunit_kzalloc() here and avoid needing the manual call to kfree? This also holds for the other test cases where they don't have early calls to kfree(). Doing so would also let you use KUNIT_ASSERT's without fear of leaking these allocations. > + src->count = TEST_BOUNDS; > + memset(src->flex, 'A', flex_array_size(src, flex, TEST_BOUNDS)); > + src->flex[src->count - 2] = 0x14141414; > + src->flex[src->count - 1] = 0x24242424; > + > + /* Prepare open-coded destination, alloc only. */ > + dst = kzalloc(struct_size(src, flex, TEST_BOUNDS), GFP_KERNEL); > + /* Pre-fill with 0xFE marker. */ > + memset(dst, 0xFE, struct_size(src, flex, TEST_BOUNDS)); > + /* Pretend we're 1 element smaller. */ > + dst->count = TEST_TARGET; > + > + /* Pretend to match the target destination size. */ > + src->count = TEST_TARGET; > + > + rc = flex_cpy(dst, src); > + KUNIT_EXPECT_EQ(test, rc, 0); > + CHECK_COPY(dst); > + /* Item past last copied item is unchanged from initial memset. */ > + KUNIT_EXPECT_EQ(test, dst->flex[dst->count], 0xFEFEFEFE); > + > + /* Now trip overflow, and verify we didn't clobber beyond end. */ > + src->count = TEST_BOUNDS; > + rc = flex_cpy(dst, src); > + KUNIT_EXPECT_EQ(test, rc, -E2BIG); > + /* Item past last copied item is unchanged from initial memset. */ > + KUNIT_EXPECT_EQ(test, dst->flex[dst->count], 0xFEFEFEFE); > + > + /* Reset destination contents. */ > + memset(dst, 0xFD, struct_size(src, flex, TEST_BOUNDS)); > + dst->count = TEST_TARGET; > + > + /* Copy less than max. */ > + src->count = TEST_SMALL; > + rc = flex_cpy(dst, src); > + KUNIT_EXPECT_EQ(test, rc, 0); > + /* Verify count was adjusted. */ > + KUNIT_EXPECT_EQ(test, dst->count, TEST_SMALL); Just an FYI, macros get evaluated before the expect macros can stringify them. So the error message would look something like Expected dest->count == 10 but dest->count = 9 Not a big concern, but just noting that "TEST_SMALL" won't be visible at all. Could opt for KUNIT_EXPECT_EQ_MSG(test, dst->count, TEST_SMALL, "my custom extra message"); if you think it'd be usable to make the test more grokkable. > + /* Verify element beyond src size was wiped. */ > + KUNIT_EXPECT_EQ(test, dst->flex[TEST_SMALL], 0); > + /* Verify element beyond original dst size was untouched. */ > + KUNIT_EXPECT_EQ(test, dst->flex[TEST_TARGET], 0xFDFDFDFD); > + > + kfree(dst); > + kfree(src); > +#undef TEST_BOUNDS > +#undef TEST_TARGET > +#undef TEST_SMALL > +} > + > +static void flex_dup_test(struct kunit *test) > +{ > +#define TEST_TARGET 12 > + struct flex_cpy_obj *src, *dst = NULL, **null = NULL; > + struct flex_dup_obj *encap = NULL; > + unsigned long padding; > + int i, rc; > + > + /* Prepare open-coded source. */ > + src = kzalloc(struct_size(src, flex, TEST_TARGET), GFP_KERNEL); > + src->count = TEST_TARGET; > + memset(src->flex, 'A', flex_array_size(src, flex, TEST_TARGET)); > + src->flex[src->count - 1] = 0x14141414; > + > + /* Reject NULL @alloc. */ > + rc = flex_dup(null, src, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, -EINVAL); > + > + /* Check good copy. */ > + rc = flex_dup(&dst, src, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, 0); > + KUNIT_ASSERT_TRUE(test, dst != NULL); > + CHECK_COPY(dst); > + > + /* Reject non-NULL *@alloc. */ > + rc = flex_dup(&dst, src, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, -EINVAL); > + > + kfree(dst); > + > + /* Check good encap copy. */ > + rc = __flex_dup(&encap, .fas, src, GFP_KERNEL); > + KUNIT_EXPECT_EQ(test, rc, 0); > + KUNIT_ASSERT_TRUE(test, dst != NULL); FYI, there's a new KUNIT_ASSERT_NOT_NULL() macro in the -kselftest/kunit branch, https://patchwork.kernel.org/project/linux-kselftest/patch/20220211164246.410079-1-ribalda@chromium.org/ But that's not planned for inclusion into mainline until 5.19, so leaving this as-is is better for now.
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 9077bb38bc93..8bae6b169c50 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2551,11 +2551,6 @@ config OVERFLOW_KUNIT_TEST Builds unit tests for the check_*_overflow(), size_*(), allocation, and related 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 STACKINIT_KUNIT_TEST tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS depends on KUNIT @@ -2567,6 +2562,13 @@ config STACKINIT_KUNIT_TEST CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. +config FLEX_ARRAY_KUNIT_TEST + tristate "Test flex_*() family of helper functions at runtime" if !KUNIT_ALL_TESTS + depends on KUNIT + default KUNIT_ALL_TESTS + help + Builds unit tests for flexible array copy helper functions. + config TEST_UDELAY tristate "udelay test driver" help diff --git a/lib/Makefile b/lib/Makefile index 6b9ffc1bd1ee..9884318db330 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -366,6 +366,7 @@ obj-$(CONFIG_MEMCPY_KUNIT_TEST) += memcpy_kunit.o obj-$(CONFIG_OVERFLOW_KUNIT_TEST) += overflow_kunit.o CFLAGS_stackinit_kunit.o += $(call cc-disable-warning, switch-unreachable) obj-$(CONFIG_STACKINIT_KUNIT_TEST) += stackinit_kunit.o +obj-$(CONFIG_FLEX_ARRAY_KUNIT_TEST) += flex_array_kunit.o obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) += devmem_is_allowed.o diff --git a/lib/flex_array_kunit.c b/lib/flex_array_kunit.c new file mode 100644 index 000000000000..48bee88945b4 --- /dev/null +++ b/lib/flex_array_kunit.c @@ -0,0 +1,523 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Test cases for flex_*() array manipulation helpers. + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <kunit/test.h> +#include <linux/device.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/flex_array.h> + +#define COMPARE_STRUCTS(STRUCT_A, STRUCT_B) do { \ + STRUCT_A *ptr_A; \ + STRUCT_B *ptr_B; \ + int rc; \ + size_t size_A, size_B; \ + \ + /* matching types for flex array elements and count */ \ + KUNIT_EXPECT_EQ(test, sizeof(*ptr_A), sizeof(*ptr_B)); \ + KUNIT_EXPECT_TRUE(test, __same_type(*ptr_A->data, \ + *ptr_B->__flex_array_elements)); \ + KUNIT_EXPECT_TRUE(test, __same_type(ptr_A->datalen, \ + ptr_B->__flex_array_elements_count)); \ + KUNIT_EXPECT_EQ(test, sizeof(*ptr_A->data), \ + sizeof(*ptr_B->__flex_array_elements)); \ + KUNIT_EXPECT_EQ(test, offsetof(typeof(*ptr_A), data), \ + offsetof(typeof(*ptr_B), \ + __flex_array_elements)); \ + KUNIT_EXPECT_EQ(test, offsetof(typeof(*ptr_A), datalen), \ + offsetof(typeof(*ptr_B), \ + __flex_array_elements_count)); \ + \ + /* struct_size() vs __fas_bytes() */ \ + size_A = struct_size(ptr_A, data, 13); \ + rc = __fas_bytes(ptr_B, __flex_array_elements, \ + __flex_array_elements_count, 13, &size_B); \ + KUNIT_EXPECT_EQ(test, rc, 0); \ + KUNIT_EXPECT_EQ(test, size_A, size_B); \ + \ + /* flex_array_size() vs __fas_elements_bytes() */ \ + size_A = flex_array_size(ptr_A, data, 13); \ + rc = __fas_elements_bytes(ptr_B, __flex_array_elements, \ + __flex_array_elements_count, 13, &size_B); \ + KUNIT_EXPECT_EQ(test, rc, 0); \ + KUNIT_EXPECT_EQ(test, size_A, size_B); \ + \ + KUNIT_EXPECT_EQ(test, sizeof(*ptr_A) + size_A, \ + offsetof(typeof(*ptr_A), data) + \ + (sizeof(*ptr_A->data) * 13)); \ + KUNIT_EXPECT_EQ(test, sizeof(*ptr_B) + size_B, \ + offsetof(typeof(*ptr_B), \ + __flex_array_elements) + \ + (sizeof(*ptr_B->__flex_array_elements) * \ + 13)); \ +} while (0) + +struct normal { + size_t datalen; + u32 data[]; +}; + +struct decl_normal { + DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(size_t, datalen); + DECLARE_FLEX_ARRAY_ELEMENTS(u32, data); +}; + +struct aligned { + unsigned short datalen; + char data[] __aligned(__alignof__(u64)); +}; + +struct decl_aligned { + DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(unsigned short, datalen); + DECLARE_FLEX_ARRAY_ELEMENTS(char, data) __aligned(__alignof__(u64)); +}; + +static void struct_test(struct kunit *test) +{ + COMPARE_STRUCTS(struct normal, struct decl_normal); + COMPARE_STRUCTS(struct aligned, struct decl_aligned); +} + +/* Flexible array structure with internal padding. */ +struct flex_cpy_obj { + DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(u8, count); + unsigned long empty; + char induce_padding; + /* padding ends up here */ + unsigned long after_padding; + DECLARE_FLEX_ARRAY_ELEMENTS(u32, flex); +}; + +/* Encapsulating flexible array structure. */ +struct flex_dup_obj { + unsigned long flags; + int junk; + struct flex_cpy_obj fas; +}; + +/* Flexible array struct of only bytes. */ +struct tiny_flex { + DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(u8, count); + DECLARE_FLEX_ARRAY_ELEMENTS(u8, byte_array); +}; + +#define CHECK_COPY(ptr) do { \ + typeof(*(ptr)) *_cc_dst = (ptr); \ + KUNIT_EXPECT_EQ(test, _cc_dst->induce_padding, 0); \ + memcpy(&padding, &_cc_dst->induce_padding + sizeof(_cc_dst->induce_padding), \ + sizeof(padding)); \ + /* Padding should be zero too. */ \ + KUNIT_EXPECT_EQ(test, padding, 0); \ + KUNIT_EXPECT_EQ(test, src->count, _cc_dst->count); \ + KUNIT_EXPECT_EQ(test, _cc_dst->count, TEST_TARGET); \ + for (i = 0; i < _cc_dst->count - 1; i++) { \ + /* 'A' is 0x41, and here repeated in a u32. */ \ + KUNIT_EXPECT_EQ(test, _cc_dst->flex[i], 0x41414141); \ + } \ + /* Last item should be different. */ \ + KUNIT_EXPECT_EQ(test, _cc_dst->flex[_cc_dst->count - 1], 0x14141414); \ +} while (0) + +/* Test copying from one flexible array struct into another. */ +static void flex_cpy_test(struct kunit *test) +{ +#define TEST_BOUNDS 13 +#define TEST_TARGET 12 +#define TEST_SMALL 10 + struct flex_cpy_obj *src, *dst; + unsigned long padding; + int i, rc; + + /* Prepare open-coded source. */ + src = kzalloc(struct_size(src, flex, TEST_BOUNDS), GFP_KERNEL); + src->count = TEST_BOUNDS; + memset(src->flex, 'A', flex_array_size(src, flex, TEST_BOUNDS)); + src->flex[src->count - 2] = 0x14141414; + src->flex[src->count - 1] = 0x24242424; + + /* Prepare open-coded destination, alloc only. */ + dst = kzalloc(struct_size(src, flex, TEST_BOUNDS), GFP_KERNEL); + /* Pre-fill with 0xFE marker. */ + memset(dst, 0xFE, struct_size(src, flex, TEST_BOUNDS)); + /* Pretend we're 1 element smaller. */ + dst->count = TEST_TARGET; + + /* Pretend to match the target destination size. */ + src->count = TEST_TARGET; + + rc = flex_cpy(dst, src); + KUNIT_EXPECT_EQ(test, rc, 0); + CHECK_COPY(dst); + /* Item past last copied item is unchanged from initial memset. */ + KUNIT_EXPECT_EQ(test, dst->flex[dst->count], 0xFEFEFEFE); + + /* Now trip overflow, and verify we didn't clobber beyond end. */ + src->count = TEST_BOUNDS; + rc = flex_cpy(dst, src); + KUNIT_EXPECT_EQ(test, rc, -E2BIG); + /* Item past last copied item is unchanged from initial memset. */ + KUNIT_EXPECT_EQ(test, dst->flex[dst->count], 0xFEFEFEFE); + + /* Reset destination contents. */ + memset(dst, 0xFD, struct_size(src, flex, TEST_BOUNDS)); + dst->count = TEST_TARGET; + + /* Copy less than max. */ + src->count = TEST_SMALL; + rc = flex_cpy(dst, src); + KUNIT_EXPECT_EQ(test, rc, 0); + /* Verify count was adjusted. */ + KUNIT_EXPECT_EQ(test, dst->count, TEST_SMALL); + /* Verify element beyond src size was wiped. */ + KUNIT_EXPECT_EQ(test, dst->flex[TEST_SMALL], 0); + /* Verify element beyond original dst size was untouched. */ + KUNIT_EXPECT_EQ(test, dst->flex[TEST_TARGET], 0xFDFDFDFD); + + kfree(dst); + kfree(src); +#undef TEST_BOUNDS +#undef TEST_TARGET +#undef TEST_SMALL +} + +static void flex_dup_test(struct kunit *test) +{ +#define TEST_TARGET 12 + struct flex_cpy_obj *src, *dst = NULL, **null = NULL; + struct flex_dup_obj *encap = NULL; + unsigned long padding; + int i, rc; + + /* Prepare open-coded source. */ + src = kzalloc(struct_size(src, flex, TEST_TARGET), GFP_KERNEL); + src->count = TEST_TARGET; + memset(src->flex, 'A', flex_array_size(src, flex, TEST_TARGET)); + src->flex[src->count - 1] = 0x14141414; + + /* Reject NULL @alloc. */ + rc = flex_dup(null, src, GFP_KERNEL); + KUNIT_EXPECT_EQ(test, rc, -EINVAL); + + /* Check good copy. */ + rc = flex_dup(&dst, src, GFP_KERNEL); + KUNIT_EXPECT_EQ(test, rc, 0); + KUNIT_ASSERT_TRUE(test, dst != NULL); + CHECK_COPY(dst); + + /* Reject non-NULL *@alloc. */ + rc = flex_dup(&dst, src, GFP_KERNEL); + KUNIT_EXPECT_EQ(test, rc, -EINVAL); + + kfree(dst); + + /* Check good encap copy. */ + rc = __flex_dup(&encap, .fas, src, GFP_KERNEL); + KUNIT_EXPECT_EQ(test, rc, 0); + KUNIT_ASSERT_TRUE(test, dst != NULL); + CHECK_COPY(&encap->fas); + /* Check that items external to "fas" are zero. */ + KUNIT_EXPECT_EQ(test, encap->flags, 0); + KUNIT_EXPECT_EQ(test, encap->junk, 0); + kfree(encap); +#undef MAGIC_WORD +#undef TEST_TARGET +} + +static void mem_to_flex_test(struct kunit *test) +{ +#define TEST_TARGET 9 +#define TEST_MAX U8_MAX +#define MAGIC_WORD 0x03030303 + u8 magic_byte = MAGIC_WORD & 0xff; + struct flex_cpy_obj *dst; + size_t big = (size_t)INT_MAX + 1; + char small[] = "Hello"; + char *src; + u32 src_len; + int rc; + + /* Open coded allocations, 1 larger than actually used. */ + src_len = flex_array_size(dst, flex, TEST_MAX + 1); + src = kzalloc(src_len, GFP_KERNEL); + dst = kzalloc(struct_size(dst, flex, TEST_MAX + 1), GFP_KERNEL); + dst->count = TEST_TARGET; + + /* Fill source. */ + memset(src, magic_byte, src_len); + + /* Short copy is fine. */ + KUNIT_EXPECT_EQ(test, dst->flex[0], 0); + KUNIT_EXPECT_EQ(test, dst->flex[1], 0); + rc = mem_to_flex(dst, src, 1); + KUNIT_EXPECT_EQ(test, rc, 0); + KUNIT_EXPECT_EQ(test, dst->count, 1); + KUNIT_EXPECT_EQ(test, dst->after_padding, 0); + KUNIT_EXPECT_EQ(test, dst->flex[0], MAGIC_WORD); + KUNIT_EXPECT_EQ(test, dst->flex[1], 0); + dst->count = TEST_TARGET; + + /* Reject negative elements count. */ + rc = mem_to_flex(dst, small, -1); + KUNIT_EXPECT_EQ(test, rc, -E2BIG); + /* Make sure dst is unchanged. */ + KUNIT_EXPECT_EQ(test, dst->flex[0], MAGIC_WORD); + KUNIT_EXPECT_EQ(test, dst->flex[1], 0); + + /* Reject compile-time read overflow. */ + rc = mem_to_flex(dst, small, 20); + KUNIT_EXPECT_EQ(test, rc, -E2BIG); + /* Make sure dst is unchanged. */ + KUNIT_EXPECT_EQ(test, dst->flex[0], MAGIC_WORD); + KUNIT_EXPECT_EQ(test, dst->flex[1], 0); + + /* Reject giant buffer source. */ + rc = mem_to_flex(dst, small, big); + KUNIT_EXPECT_EQ(test, rc, -E2BIG); + /* Make sure dst is unchanged. */ + KUNIT_EXPECT_EQ(test, dst->flex[0], MAGIC_WORD); + KUNIT_EXPECT_EQ(test, dst->flex[1], 0); + + /* Copy beyond storage size is rejected. */ + dst->count = TEST_MAX; + KUNIT_EXPECT_EQ(test, dst->flex[TEST_MAX - 1], 0); + KUNIT_EXPECT_EQ(test, dst->flex[TEST_MAX], 0); + rc = mem_to_flex(dst, src, TEST_MAX + 1); + KUNIT_EXPECT_EQ(test, rc, -E2BIG); + /* Make sure dst is unchanged. */ + KUNIT_EXPECT_EQ(test, dst->flex[0], MAGIC_WORD); + KUNIT_EXPECT_EQ(test, dst->flex[1], 0); + + kfree(dst); + kfree(src); +#undef MAGIC_WORD +#undef TEST_MAX +#undef TEST_TARGET +} + +static void mem_to_flex_dup_test(struct kunit *test) +{ +#define ELEMENTS_COUNT 259 +#define MAGIC_WORD 0xABABABAB + u8 magic_byte = MAGIC_WORD & 0xff; + struct flex_dup_obj *obj = NULL; + struct tiny_flex *tiny = NULL, **null = NULL; + size_t src_len, count, big = (size_t)INT_MAX + 1; + char small[] = "Hello"; + u8 *src; + int rc; + + src_len = struct_size(tiny, byte_array, ELEMENTS_COUNT); + src = kzalloc(src_len, GFP_KERNEL); + KUNIT_ASSERT_TRUE(test, src != NULL); + /* Fill with bytes. */ + memset(src, magic_byte, src_len); + KUNIT_EXPECT_EQ(test, src[0], magic_byte); + KUNIT_EXPECT_EQ(test, src[src_len / 2], magic_byte); + KUNIT_EXPECT_EQ(test, src[src_len - 1], magic_byte); + + /* Reject storage exceeding elements_count type. */ + count = ELEMENTS_COUNT; + rc = mem_to_flex_dup(&tiny, src, count, GFP_KERNEL); + KUNIT_EXPECT_EQ(test, rc, -E2BIG); + KUNIT_EXPECT_TRUE(test, tiny == NULL); + + /* Reject negative elements count. */ + rc = mem_to_flex_dup(&tiny, src, -1, GFP_KERNEL); + KUNIT_EXPECT_EQ(test, rc, -E2BIG); + KUNIT_EXPECT_TRUE(test, tiny == NULL); + + /* Reject compile-time read overflow. */ + rc = mem_to_flex_dup(&tiny, small, 20, GFP_KERNEL); + KUNIT_EXPECT_EQ(test, rc, -E2BIG); + KUNIT_EXPECT_TRUE(test, tiny == NULL); + + /* Reject giant buffer source. */ + rc = mem_to_flex_dup(&tiny, small, big, GFP_KERNEL); + KUNIT_EXPECT_EQ(test, rc, -E2BIG); + KUNIT_EXPECT_TRUE(test, tiny == NULL); + + /* Reject NULL @alloc. */ + rc = mem_to_flex_dup(null, src, count, GFP_KERNEL); + KUNIT_EXPECT_EQ(test, rc, -EINVAL); + + /* Allow reasonable count.*/ + count = ELEMENTS_COUNT / 2; + rc = mem_to_flex_dup(&tiny, src, count, GFP_KERNEL); + KUNIT_EXPECT_EQ(test, rc, 0); + KUNIT_ASSERT_TRUE(test, tiny != NULL); + /* Spot check the copy happened. */ + KUNIT_EXPECT_EQ(test, tiny->count, count); + KUNIT_EXPECT_EQ(test, tiny->byte_array[0], magic_byte); + KUNIT_EXPECT_EQ(test, tiny->byte_array[count / 2], magic_byte); + KUNIT_EXPECT_EQ(test, tiny->byte_array[count - 1], magic_byte); + + /* Reject non-NULL *@alloc. */ + rc = mem_to_flex_dup(&tiny, src, count, GFP_KERNEL); + KUNIT_EXPECT_EQ(test, rc, -EINVAL); + kfree(tiny); + + /* Works with encapsulation too. */ + count = ELEMENTS_COUNT / 10; + rc = __mem_to_flex_dup(&obj, .fas, src, count, GFP_KERNEL); + KUNIT_EXPECT_EQ(test, rc, 0); + KUNIT_ASSERT_TRUE(test, obj != NULL); + /* Spot check the copy happened. */ + KUNIT_EXPECT_EQ(test, obj->fas.count, count); + KUNIT_EXPECT_EQ(test, obj->fas.after_padding, 0); + KUNIT_EXPECT_EQ(test, obj->fas.flex[0], MAGIC_WORD); + KUNIT_EXPECT_EQ(test, obj->fas.flex[count / 2], MAGIC_WORD); + KUNIT_EXPECT_EQ(test, obj->fas.flex[count - 1], MAGIC_WORD); + /* Check members before flexible array struct are zero. */ + KUNIT_EXPECT_EQ(test, obj->flags, 0); + KUNIT_EXPECT_EQ(test, obj->junk, 0); + kfree(obj); +#undef MAGIC_WORD +#undef ELEMENTS_COUNT +} + +static void flex_to_mem_test(struct kunit *test) +{ +#define ELEMENTS_COUNT 200 +#define MAGIC_WORD 0xF1F2F3F4 + struct flex_cpy_obj *src; + typeof(*src->flex) *cast; + size_t src_len = struct_size(src, flex, ELEMENTS_COUNT); + size_t copy_len = flex_array_size(src, flex, ELEMENTS_COUNT); + int i, rc; + size_t bytes = 0; + u8 too_small; + u8 *dst; + + /* Create a filled flexible array struct. */ + src = kzalloc(src_len, GFP_KERNEL); + KUNIT_ASSERT_TRUE(test, src != NULL); + src->count = ELEMENTS_COUNT; + src->after_padding = 13; + for (i = 0; i < ELEMENTS_COUNT; i++) + src->flex[i] = MAGIC_WORD; + + /* Over-allocate space to do past-src_len checking. */ + dst = kzalloc(src_len * 2, GFP_KERNEL); + KUNIT_ASSERT_TRUE(test, dst != NULL); + cast = (void *)dst; + + /* Fail if dst is too small. */ + rc = flex_to_mem(dst, copy_len - 1, src, &bytes); + KUNIT_EXPECT_EQ(test, rc, -E2BIG); + /* Make sure nothing was copied. */ + KUNIT_EXPECT_EQ(test, bytes, 0); + KUNIT_EXPECT_EQ(test, cast[0], 0); + + /* Fail if type too small to hold size of copy. */ + KUNIT_EXPECT_GT(test, copy_len, type_max(typeof(too_small))); + rc = flex_to_mem(dst, copy_len, src, &too_small); + KUNIT_EXPECT_EQ(test, rc, -E2BIG); + /* Make sure nothing was copied. */ + KUNIT_EXPECT_EQ(test, bytes, 0); + KUNIT_EXPECT_EQ(test, cast[0], 0); + + /* Check good copy. */ + rc = flex_to_mem(dst, copy_len, src, &bytes); + KUNIT_EXPECT_EQ(test, rc, 0); + KUNIT_EXPECT_EQ(test, bytes, copy_len); + /* Spot check the copy */ + KUNIT_EXPECT_EQ(test, cast[0], MAGIC_WORD); + KUNIT_EXPECT_EQ(test, cast[ELEMENTS_COUNT / 2], MAGIC_WORD); + KUNIT_EXPECT_EQ(test, cast[ELEMENTS_COUNT - 1], MAGIC_WORD); + /* Make sure nothing was written after last element. */ + KUNIT_EXPECT_EQ(test, cast[ELEMENTS_COUNT], 0); + + kfree(dst); + kfree(src); +#undef MAGIC_WORD +#undef ELEMENTS_COUNT +} + +static void flex_to_mem_dup_test(struct kunit *test) +{ +#define ELEMENTS_COUNT 210 +#define MAGIC_WORD 0xF0F1F2F3 + struct flex_dup_obj *obj, **null = NULL; + struct flex_cpy_obj *src; + typeof(*src->flex) *cast; + size_t obj_len = struct_size(obj, fas.flex, ELEMENTS_COUNT); + size_t src_len = struct_size(src, flex, ELEMENTS_COUNT); + size_t copy_len = flex_array_size(src, flex, ELEMENTS_COUNT); + int i, rc; + size_t bytes = 0; + u8 too_small = 0; + u8 *dst = NULL; + + /* Create a filled flexible array struct. */ + obj = kzalloc(obj_len, GFP_KERNEL); + KUNIT_ASSERT_TRUE(test, obj != NULL); + obj->fas.count = ELEMENTS_COUNT; + obj->fas.after_padding = 13; + for (i = 0; i < ELEMENTS_COUNT; i++) + obj->fas.flex[i] = MAGIC_WORD; + src = &obj->fas; + + /* Fail if type too small to hold size of copy. */ + KUNIT_EXPECT_GT(test, src_len, type_max(typeof(too_small))); + rc = flex_to_mem_dup(&dst, &too_small, src, GFP_KERNEL); + KUNIT_EXPECT_EQ(test, rc, -E2BIG); + KUNIT_EXPECT_TRUE(test, dst == NULL); + KUNIT_EXPECT_EQ(test, too_small, 0); + + /* Fail if @alloc_size is NULL. */ + KUNIT_EXPECT_TRUE(test, dst == NULL); + rc = flex_to_mem_dup(&dst, dst, src, GFP_KERNEL); + KUNIT_EXPECT_EQ(test, rc, -EINVAL); + KUNIT_EXPECT_TRUE(test, dst == NULL); + + /* Fail if @alloc is NULL. */ + rc = flex_to_mem_dup(null, &bytes, src, GFP_KERNEL); + KUNIT_EXPECT_EQ(test, rc, -EINVAL); + KUNIT_EXPECT_TRUE(test, dst == NULL); + KUNIT_EXPECT_EQ(test, bytes, 0); + + /* Check good copy. */ + rc = flex_to_mem_dup(&dst, &bytes, src, GFP_KERNEL); + KUNIT_EXPECT_EQ(test, rc, 0); + KUNIT_EXPECT_TRUE(test, dst != NULL); + KUNIT_EXPECT_EQ(test, bytes, copy_len); + cast = (void *)dst; + /* Spot check the copy */ + KUNIT_EXPECT_EQ(test, cast[0], MAGIC_WORD); + KUNIT_EXPECT_EQ(test, cast[ELEMENTS_COUNT / 2], MAGIC_WORD); + KUNIT_EXPECT_EQ(test, cast[ELEMENTS_COUNT - 1], MAGIC_WORD); + + /* Fail if *@alloc is non-NULL. */ + bytes = 0; + rc = flex_to_mem_dup(&dst, &bytes, src, GFP_KERNEL); + KUNIT_EXPECT_EQ(test, rc, -EINVAL); + KUNIT_EXPECT_EQ(test, bytes, 0); + + kfree(dst); + kfree(obj); +#undef MAGIC_WORD +#undef ELEMENTS_COUNT +} + +static struct kunit_case flex_array_test_cases[] = { + KUNIT_CASE(struct_test), + KUNIT_CASE(flex_cpy_test), + KUNIT_CASE(flex_dup_test), + KUNIT_CASE(mem_to_flex_test), + KUNIT_CASE(mem_to_flex_dup_test), + KUNIT_CASE(flex_to_mem_test), + KUNIT_CASE(flex_to_mem_dup_test), + {} +}; + +static struct kunit_suite flex_array_test_suite = { + .name = "flex_array", + .test_cases = flex_array_test_cases, +}; + +kunit_test_suite(flex_array_test_suite); + +MODULE_LICENSE("GPL");
Add tests for the new flexible array structure helpers. These can be run with: make ARCH=um mrproper ./tools/testing/kunit/kunit.py config ./tools/testing/kunit/kunit.py run flex_array Cc: David Gow <davidgow@google.com> Cc: kunit-dev@googlegroups.com Signed-off-by: Kees Cook <keescook@chromium.org> --- lib/Kconfig.debug | 12 +- lib/Makefile | 1 + lib/flex_array_kunit.c | 523 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 531 insertions(+), 5 deletions(-) create mode 100644 lib/flex_array_kunit.c