[PATCH 6/6] kunit/fortify: Validate __alloc_size attribute results
From: Kees Cook
Date: Tue Nov 01 2022 - 18:34:27 EST
Validate the effect of the __alloc_size attribute on allocators. If the
compiler doesn't support __builtin_dynamic_object_size(), skip the
associated tests.
(For GCC, just remove the "--make_options" line below...)
$ ./tools/testing/kunit/kunit.py run --arch x86_64 \
--kconfig_add CONFIG_FORTIFY_SOURCE=y \
--make_options LLVM=1
fortify
...
[15:16:30] ================== fortify (10 subtests) ===================
[15:16:30] [PASSED] known_sizes_test
[15:16:30] [PASSED] control_flow_split_test
[15:16:30] [PASSED] alloc_size_kmalloc_const_test
[15:16:30] [PASSED] alloc_size_kmalloc_dynamic_test
[15:16:30] [PASSED] alloc_size_vmalloc_const_test
[15:16:30] [PASSED] alloc_size_vmalloc_dynamic_test
[15:16:30] [PASSED] alloc_size_kvmalloc_const_test
[15:16:30] [PASSED] alloc_size_kvmalloc_dynamic_test
[15:16:30] [PASSED] alloc_size_devm_kmalloc_const_test
[15:16:30] [PASSED] alloc_size_devm_kmalloc_dynamic_test
[15:16:30] ===================== [PASSED] fortify =====================
[15:16:30] ============================================================
[15:16:30] Testing complete. Ran 10 tests: passed: 10
[15:16:31] Elapsed time: 8.348s total, 0.002s configuring, 6.923s building, 1.075s running
For earlier GCC prior to version 12, the dynamic tests will be skipped:
[15:18:59] ================== fortify (10 subtests) ===================
[15:18:59] [PASSED] known_sizes_test
[15:18:59] [PASSED] control_flow_split_test
[15:18:59] [PASSED] alloc_size_kmalloc_const_test
[15:18:59] [SKIPPED] alloc_size_kmalloc_dynamic_test
[15:18:59] [PASSED] alloc_size_vmalloc_const_test
[15:18:59] [SKIPPED] alloc_size_vmalloc_dynamic_test
[15:18:59] [PASSED] alloc_size_kvmalloc_const_test
[15:18:59] [SKIPPED] alloc_size_kvmalloc_dynamic_test
[15:18:59] [PASSED] alloc_size_devm_kmalloc_const_test
[15:18:59] [SKIPPED] alloc_size_devm_kmalloc_dynamic_test
[15:18:59] ===================== [PASSED] fortify =====================
[15:18:59] ============================================================
[15:18:59] Testing complete. Ran 10 tests: passed: 6, skipped: 4
[15:18:59] Elapsed time: 11.965s total, 0.002s configuring, 10.540s building, 1.068s running
Cc: David Gow <davidgow@xxxxxxxxxx>
Cc: linux-hardening@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
lib/Makefile | 1 +
lib/fortify_kunit.c | 255 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 256 insertions(+)
diff --git a/lib/Makefile b/lib/Makefile
index 77c7951c8cf0..d197079ef22a 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -377,6 +377,7 @@ obj-$(CONFIG_IS_SIGNED_TYPE_KUNIT_TEST) += is_signed_type_kunit.o
obj-$(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
+CFLAGS_fortify_kunit.o += $(call cc-disable-warning, unsequenced)
obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o
obj-$(CONFIG_STRSCPY_KUNIT_TEST) += strscpy_kunit.o
obj-$(CONFIG_SIPHASH_KUNIT_TEST) += siphash_kunit.o
diff --git a/lib/fortify_kunit.c b/lib/fortify_kunit.c
index 409af07f340a..78acfdbda835 100644
--- a/lib/fortify_kunit.c
+++ b/lib/fortify_kunit.c
@@ -16,7 +16,10 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <kunit/test.h>
+#include <linux/device.h>
+#include <linux/slab.h>
#include <linux/string.h>
+#include <linux/vmalloc.h>
static const char array_of_10[] = "this is 10";
static const char *ptr_of_11 = "this is 11!";
@@ -60,9 +63,261 @@ static void control_flow_split_test(struct kunit *test)
KUNIT_EXPECT_EQ(test, want_minus_one(pick), SIZE_MAX);
}
+#define KUNIT_EXPECT_BOS(test, p, expected, name) \
+ KUNIT_EXPECT_EQ_MSG(test, __builtin_object_size(p, 1), \
+ expected, \
+ "__alloc_size() not working with __bos on " name "\n")
+
+#if !__has_builtin(__builtin_dynamic_object_size)
+#define KUNIT_EXPECT_BDOS(test, p, expected, name) \
+ /* Silence "unused variable 'expected'" warning. */ \
+ KUNIT_EXPECT_EQ(test, expected, expected)
+#else
+#define KUNIT_EXPECT_BDOS(test, p, expected, name) \
+ KUNIT_EXPECT_EQ_MSG(test, __builtin_dynamic_object_size(p, 1), \
+ expected, \
+ "__alloc_size() not working with __bdos on " name "\n")
+#endif
+
+/* If the execpted size is a constant value, __bos can see it. */
+#define check_const(_expected, alloc, free) do { \
+ size_t expected = (_expected); \
+ void *p = alloc; \
+ KUNIT_EXPECT_TRUE_MSG(test, p != NULL, #alloc " failed?!\n"); \
+ KUNIT_EXPECT_BOS(test, p, expected, #alloc); \
+ KUNIT_EXPECT_BDOS(test, p, expected, #alloc); \
+ free; \
+} while (0)
+
+/* If the execpted size is NOT a constant value, __bos CANNOT see it. */
+#define check_dynamic(_expected, alloc, free) do { \
+ size_t expected = (_expected); \
+ void *p = alloc; \
+ KUNIT_EXPECT_TRUE_MSG(test, p != NULL, #alloc " failed?!\n"); \
+ KUNIT_EXPECT_BOS(test, p, SIZE_MAX, #alloc); \
+ KUNIT_EXPECT_BDOS(test, p, expected, #alloc); \
+ free; \
+} while (0)
+
+/* Assortment of constant-value kinda-edge cases. */
+#define CONST_TEST_BODY(TEST_alloc) do { \
+ /* Special-case vmalloc()-family to skip 0-sized allocs. */ \
+ if (strcmp(#TEST_alloc, "TEST_vmalloc") != 0) \
+ TEST_alloc(check_const, 0, 0); \
+ TEST_alloc(check_const, 1, 1); \
+ TEST_alloc(check_const, 128, 128); \
+ TEST_alloc(check_const, 1023, 1023); \
+ TEST_alloc(check_const, 1025, 1025); \
+ TEST_alloc(check_const, 4096, 4096); \
+ TEST_alloc(check_const, 4097, 4097); \
+} while (0)
+
+static volatile size_t zero_size;
+static volatile size_t unknown_size = 50;
+
+#if !__has_builtin(__builtin_dynamic_object_size)
+#define DYNAMIC_TEST_BODY(TEST_alloc) \
+ kunit_skip(test, "Compiler is missing __builtin_dynamic_object_size() support\n")
+#else
+#define DYNAMIC_TEST_BODY(TEST_alloc) do { \
+ size_t size = unknown_size; \
+ \
+ /* \
+ * Expected size is "size" in each test, before it is then \
+ * internally incremented in each test. Requires we disable \
+ * -Wunsequenced. \
+ */ \
+ TEST_alloc(check_dynamic, size, size++); \
+ /* Make sure incrementing actually happened. */ \
+ KUNIT_EXPECT_NE(test, size, unknown_size); \
+} while (0)
+#endif
+
+#define DEFINE_ALLOC_SIZE_TEST_PAIR(allocator) \
+static void alloc_size_##allocator##_const_test(struct kunit *test) \
+{ \
+ CONST_TEST_BODY(TEST_##allocator); \
+} \
+static void alloc_size_##allocator##_dynamic_test(struct kunit *test) \
+{ \
+ DYNAMIC_TEST_BODY(TEST_##allocator); \
+}
+
+#define TEST_kmalloc(checker, expected_size, alloc_size) do { \
+ gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; \
+ void *orig; \
+ size_t len; \
+ \
+ checker(expected_size, kmalloc(alloc_size, gfp), \
+ kfree(p)); \
+ checker(expected_size, \
+ kmalloc_node(alloc_size, gfp, NUMA_NO_NODE), \
+ kfree(p)); \
+ checker(expected_size, kzalloc(alloc_size, gfp), \
+ kfree(p)); \
+ checker(expected_size, \
+ kzalloc_node(alloc_size, gfp, NUMA_NO_NODE), \
+ kfree(p)); \
+ checker(expected_size, kcalloc(1, alloc_size, gfp), \
+ kfree(p)); \
+ checker(expected_size, kcalloc(alloc_size, 1, gfp), \
+ kfree(p)); \
+ checker(expected_size, \
+ kcalloc_node(1, alloc_size, gfp, NUMA_NO_NODE), \
+ kfree(p)); \
+ checker(expected_size, \
+ kcalloc_node(alloc_size, 1, gfp, NUMA_NO_NODE), \
+ kfree(p)); \
+ checker(expected_size, kmalloc_array(1, alloc_size, gfp), \
+ kfree(p)); \
+ checker(expected_size, kmalloc_array(alloc_size, 1, gfp), \
+ kfree(p)); \
+ checker(expected_size, \
+ kmalloc_array_node(1, alloc_size, gfp, NUMA_NO_NODE), \
+ kfree(p)); \
+ checker(expected_size, \
+ kmalloc_array_node(alloc_size, 1, gfp, NUMA_NO_NODE), \
+ kfree(p)); \
+ checker(expected_size, __kmalloc(alloc_size, gfp), \
+ kfree(p)); \
+ checker(expected_size, \
+ __kmalloc_node(alloc_size, gfp, NUMA_NO_NODE), \
+ kfree(p)); \
+ \
+ orig = kmalloc(alloc_size, gfp); \
+ KUNIT_EXPECT_TRUE(test, orig != NULL); \
+ checker((expected_size) * 2, \
+ krealloc(orig, (alloc_size) * 2, gfp), \
+ kfree(p)); \
+ orig = kmalloc(alloc_size, gfp); \
+ KUNIT_EXPECT_TRUE(test, orig != NULL); \
+ checker((expected_size) * 2, \
+ krealloc_array(orig, 1, (alloc_size) * 2, gfp), \
+ kfree(p)); \
+ orig = kmalloc(alloc_size, gfp); \
+ KUNIT_EXPECT_TRUE(test, orig != NULL); \
+ checker((expected_size) * 2, \
+ krealloc_array(orig, (alloc_size) * 2, 1, gfp), \
+ kfree(p)); \
+ \
+ len = 11; \
+ /* Using memdup() with fixed size, so force unknown length. */ \
+ if (!__builtin_constant_p(expected_size)) \
+ len += zero_size; \
+ checker(len, kmemdup("hello there", len, gfp), kfree(p)); \
+} while (0)
+DEFINE_ALLOC_SIZE_TEST_PAIR(kmalloc)
+
+/* Sizes are in pages, not bytes. */
+#define TEST_vmalloc(checker, expected_pages, alloc_pages) do { \
+ gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; \
+ checker((expected_pages) * PAGE_SIZE, \
+ vmalloc((alloc_pages) * PAGE_SIZE), vfree(p)); \
+ checker((expected_pages) * PAGE_SIZE, \
+ vzalloc((alloc_pages) * PAGE_SIZE), vfree(p)); \
+ checker((expected_pages) * PAGE_SIZE, \
+ __vmalloc((alloc_pages) * PAGE_SIZE, gfp), vfree(p)); \
+} while (0)
+DEFINE_ALLOC_SIZE_TEST_PAIR(vmalloc)
+
+/* Sizes are in pages (and open-coded for side-effects), not bytes. */
+#define TEST_kvmalloc(checker, expected_pages, alloc_pages) do { \
+ gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; \
+ size_t prev_size; \
+ void *orig; \
+ \
+ checker((expected_pages) * PAGE_SIZE, \
+ kvmalloc((alloc_pages) * PAGE_SIZE, gfp), \
+ vfree(p)); \
+ checker((expected_pages) * PAGE_SIZE, \
+ kvmalloc_node((alloc_pages) * PAGE_SIZE, gfp, NUMA_NO_NODE), \
+ vfree(p)); \
+ checker((expected_pages) * PAGE_SIZE, \
+ kvzalloc((alloc_pages) * PAGE_SIZE, gfp), \
+ vfree(p)); \
+ checker((expected_pages) * PAGE_SIZE, \
+ kvzalloc_node((alloc_pages) * PAGE_SIZE, gfp, NUMA_NO_NODE), \
+ vfree(p)); \
+ checker((expected_pages) * PAGE_SIZE, \
+ kvcalloc(1, (alloc_pages) * PAGE_SIZE, gfp), \
+ vfree(p)); \
+ checker((expected_pages) * PAGE_SIZE, \
+ kvcalloc((alloc_pages) * PAGE_SIZE, 1, gfp), \
+ vfree(p)); \
+ checker((expected_pages) * PAGE_SIZE, \
+ kvmalloc_array(1, (alloc_pages) * PAGE_SIZE, gfp), \
+ vfree(p)); \
+ checker((expected_pages) * PAGE_SIZE, \
+ kvmalloc_array((alloc_pages) * PAGE_SIZE, 1, gfp), \
+ vfree(p)); \
+ \
+ prev_size = (expected_pages) * PAGE_SIZE; \
+ orig = kvmalloc(prev_size, gfp); \
+ KUNIT_EXPECT_TRUE(test, orig != NULL); \
+ checker(((expected_pages) * PAGE_SIZE) * 2, \
+ kvrealloc(orig, prev_size, \
+ ((alloc_pages) * PAGE_SIZE) * 2, gfp), \
+ kvfree(p)); \
+} while (0)
+DEFINE_ALLOC_SIZE_TEST_PAIR(kvmalloc)
+
+#define TEST_devm_kmalloc(checker, expected_size, alloc_size) do { \
+ gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; \
+ const char const dev_name[] = "fortify-test"; \
+ struct device *dev; \
+ void *orig; \
+ size_t len; \
+ \
+ /* Create dummy device for devm_kmalloc()-family tests. */ \
+ dev = root_device_register(dev_name); \
+ KUNIT_ASSERT_FALSE_MSG(test, IS_ERR(dev), \
+ "Cannot register test device\n"); \
+ \
+ checker(expected_size, devm_kmalloc(dev, alloc_size, gfp), \
+ devm_kfree(dev, p)); \
+ checker(expected_size, devm_kzalloc(dev, alloc_size, gfp), \
+ devm_kfree(dev, p)); \
+ checker(expected_size, \
+ devm_kmalloc_array(dev, 1, alloc_size, gfp), \
+ devm_kfree(dev, p)); \
+ checker(expected_size, \
+ devm_kmalloc_array(dev, alloc_size, 1, gfp), \
+ devm_kfree(dev, p)); \
+ checker(expected_size, \
+ devm_kcalloc(dev, 1, alloc_size, gfp), \
+ devm_kfree(dev, p)); \
+ checker(expected_size, \
+ devm_kcalloc(dev, alloc_size, 1, gfp), \
+ devm_kfree(dev, p)); \
+ \
+ orig = devm_kmalloc(dev, alloc_size, gfp); \
+ KUNIT_EXPECT_TRUE(test, orig != NULL); \
+ checker((expected_size) * 2, \
+ devm_krealloc(dev, orig, (alloc_size) * 2, gfp), \
+ devm_kfree(dev, p)); \
+ \
+ len = 4; \
+ /* Using memdup() with fixed size, so force unknown length. */ \
+ if (!__builtin_constant_p(expected_size)) \
+ len += zero_size; \
+ checker(len, devm_kmemdup(dev, "Ohai", len, gfp), \
+ devm_kfree(dev, p)); \
+ \
+ device_unregister(dev); \
+} while (0)
+DEFINE_ALLOC_SIZE_TEST_PAIR(devm_kmalloc)
+
static struct kunit_case fortify_test_cases[] = {
KUNIT_CASE(known_sizes_test),
KUNIT_CASE(control_flow_split_test),
+ KUNIT_CASE(alloc_size_kmalloc_const_test),
+ KUNIT_CASE(alloc_size_kmalloc_dynamic_test),
+ KUNIT_CASE(alloc_size_vmalloc_const_test),
+ KUNIT_CASE(alloc_size_vmalloc_dynamic_test),
+ KUNIT_CASE(alloc_size_kvmalloc_const_test),
+ KUNIT_CASE(alloc_size_kvmalloc_dynamic_test),
+ KUNIT_CASE(alloc_size_devm_kmalloc_const_test),
+ KUNIT_CASE(alloc_size_devm_kmalloc_dynamic_test),
{}
};
--
2.34.1