diff mbox series

kunit/fortify: Validate __alloc_size attribute results

Message ID 20221018082559.never.406-kees@kernel.org
State New
Headers
Series kunit/fortify: Validate __alloc_size attribute results |

Commit Message

Kees Cook Oct. 18, 2022, 8:27 a.m. UTC 
  Validate the effect of the __alloc_size attribute on allocators. If the
compiler doesn't support __builtin_dynamic_object_size(), skip the test.

Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
To pass this depends on the following patches:
https://lore.kernel.org/lkml/20221018073430.never.551-kees@kernel.org/
https://lore.kernel.org/lkml/20221018082232.never.213-kees@kernel.org/
To not be skipped, either GCC 12 or Clang is needed.
---
 lib/fortify_kunit.c | 92 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)

Comments

David Gow Oct. 19, 2022, 3:35 a.m. UTC | #1 
On Tue, Oct 18, 2022 at 4:27 PM Kees Cook <keescook@chromium.org> wrote:
>
> Validate the effect of the __alloc_size attribute on allocators. If the
> compiler doesn't support __builtin_dynamic_object_size(), skip the test.
>
> Cc: linux-hardening@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> To pass this depends on the following patches:
> https://lore.kernel.org/lkml/20221018073430.never.551-kees@kernel.org/
> https://lore.kernel.org/lkml/20221018082232.never.213-kees@kernel.org/
> To not be skipped, either GCC 12 or Clang is needed.
> ---

While this _looks_ good, I can't actually get the tests to pass on my
machine, with the following all having a
__builtin_dynamic_object_size() of -1:
- kmalloc_node(size++, gfp, NUMA_NO_NODE)
- kzalloc(size++, gfp)
- kzalloc_node(size++, gfp, NUMA_NO_NODE)
- kcalloc(1, size++, gfp)
- kcalloc_node(1, size++, gfp, NUMA_NO_NODE)
- kmalloc_array(1, size++, gfp)
- kmalloc_array_node(1, size++, gfp, NUMA_NO_NODE)

I've been using the following command to run the tests:
./tools/testing/kunit/kunit.py run --kconfig_add CONFIG_FORTIFY_SOURCE=y

And I've also tried it on x86_64 and arm64 under qemu, with both gcc
12.2.0 and clang 14.0.6-2, with the same failures.

Is there a dependency somewhere I've missed? (I've tried it on the
ksefltest/kunit branch, with the mentioned dependencies applied, and
also on your for-next/hardening branch, with the missing patches
applied.)

Cheers,
-- David

>  lib/fortify_kunit.c | 92 +++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 92 insertions(+)
>
> diff --git a/lib/fortify_kunit.c b/lib/fortify_kunit.c
> index 409af07f340a..5076ba11adfd 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/string.h>
> +#include <linux/slab.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 +63,98 @@ static void control_flow_split_test(struct kunit *test)
>         KUNIT_EXPECT_EQ(test, want_minus_one(pick), SIZE_MAX);
>  }
>
> +#define check_alloc(alloc, free)       do {                            \
> +       size_t expected = size;                                         \
> +       void *p = alloc;                                                \
> +       KUNIT_EXPECT_TRUE_MSG(test, p != NULL, #alloc " failed?!\n");   \
> +       KUNIT_EXPECT_EQ_MSG(test, __builtin_dynamic_object_size(p, 1),  \
> +               expected,                                               \
> +               "__alloc_size() not working with " #alloc "\n");        \
> +       free;                                                           \
> +} while (0)
> +
> +static volatile size_t unknown_size = 50;
> +
> +static void alloc_size_test(struct kunit *test)
> +{
> +#if !__has_builtin(__builtin_dynamic_object_size)
> +       kunit_skip(test, "Compiler is missing __builtin_dynamic_object_size() support\n");
> +#else
> +       const char device_name[] = "fortify-test";
> +       struct device *dev;
> +       gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
> +       size_t size = unknown_size, prev_size;
> +       void *orig;
> +
> +       /* kmalloc()-family */
> +       check_alloc(kmalloc(size++, gfp),                       kfree(p));
> +       check_alloc(kmalloc_node(size++, gfp, NUMA_NO_NODE),    kfree(p));
> +       check_alloc(kzalloc(size++, gfp),                       kfree(p));
> +       check_alloc(kzalloc_node(size++, gfp, NUMA_NO_NODE),    kfree(p));
> +       check_alloc(kcalloc(1, size++, gfp),                    kfree(p));
> +       check_alloc(kcalloc_node(1, size++, gfp, NUMA_NO_NODE), kfree(p));
> +       check_alloc(kmalloc_array(1, size++, gfp),              kfree(p));
> +       check_alloc(kmalloc_array_node(1, size++, gfp, NUMA_NO_NODE), kfree(p));
> +       check_alloc(__kmalloc(size++, gfp),                     kfree(p));
> +       check_alloc(__kmalloc_node(size++, gfp, NUMA_NO_NODE),  kfree(p));
> +
> +       /* kmemdup() */
> +       prev_size = size;
> +       size = 11;
> +       check_alloc(kmemdup("hello there", size, gfp),          kfree(p));
> +       size = prev_size + 1;
> +
> +       /* krealloc()-family */
> +       orig = kmalloc(size++, gfp);
> +       check_alloc(krealloc(orig, size++, gfp),                kfree(p));
> +       orig = kmalloc(size++, gfp);
> +       check_alloc(krealloc_array(orig, 1, size++, gfp),       kfree(p));
> +
> +       /* vmalloc()-family */
> +       check_alloc(vmalloc(size++),                            vfree(p));
> +       check_alloc(vzalloc(size++),                            vfree(p));
> +       check_alloc(__vmalloc(size++, gfp),                     vfree(p));
> +
> +       /* kvalloc()-family */
> +       check_alloc(kvmalloc(size++, gfp),                      kvfree(p));
> +       check_alloc(kvmalloc_node(size++, gfp, NUMA_NO_NODE),   kvfree(p));
> +       check_alloc(kvzalloc(size++, gfp),                      kvfree(p));
> +       check_alloc(kvzalloc_node(size++, gfp, NUMA_NO_NODE),   kvfree(p));
> +       check_alloc(kvcalloc(1, size++, gfp),                   kvfree(p));
> +       check_alloc(kvmalloc_array(1, size++, gfp),             kvfree(p));
> +
> +       /* kvrealloc() */
> +       prev_size = size++;
> +       orig = kvmalloc(prev_size, gfp);
> +       check_alloc(kvrealloc(orig, prev_size, size++, gfp),    kfree(p));
> +
> +       /* Create dummy device for devm_kmalloc()-family tests. */
> +       dev = root_device_register(device_name);
> +       KUNIT_ASSERT_FALSE_MSG(test, IS_ERR(dev),
> +                              "Cannot register test device\n");
> +
> +       /* devm_kmalloc()-family */
> +       check_alloc(devm_kmalloc(dev, size++, gfp),             devm_kfree(dev, p));
> +       check_alloc(devm_kzalloc(dev, size++, gfp),             devm_kfree(dev, p));
> +
> +       /* devm_kmemdup() */
> +       prev_size = size;
> +       size = 4;
> +       check_alloc(devm_kmemdup(dev, "Ohai", size, gfp),       devm_kfree(dev, p));
> +       size = prev_size + 1;
> +
> +       /* devm_kremalloc() */
> +       orig = devm_kmalloc(dev, size++, gfp);
> +       check_alloc(devm_krealloc(dev, orig, size++, gfp),      devm_kfree(dev, p));
> +
> +       device_unregister(dev);
> +#endif
> +}
> +
>  static struct kunit_case fortify_test_cases[] = {
>         KUNIT_CASE(known_sizes_test),
>         KUNIT_CASE(control_flow_split_test),
> +       KUNIT_CASE(alloc_size_test),
>         {}
>  };
>
> --
> 2.34.1
>
Kees Cook Oct. 19, 2022, 5:45 a.m. UTC | #2 
On Wed, Oct 19, 2022 at 11:35:40AM +0800, David Gow wrote:
> On Tue, Oct 18, 2022 at 4:27 PM Kees Cook <keescook@chromium.org> wrote:
> >
> > Validate the effect of the __alloc_size attribute on allocators. If the
> > compiler doesn't support __builtin_dynamic_object_size(), skip the test.
> >
> > Cc: linux-hardening@vger.kernel.org
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> > To pass this depends on the following patches:
> > https://lore.kernel.org/lkml/20221018073430.never.551-kees@kernel.org/
> > https://lore.kernel.org/lkml/20221018082232.never.213-kees@kernel.org/
> > To not be skipped, either GCC 12 or Clang is needed.
> > ---
> 
> While this _looks_ good, I can't actually get the tests to pass on my
> machine, with the following all having a
> __builtin_dynamic_object_size() of -1:
> - kmalloc_node(size++, gfp, NUMA_NO_NODE)
> - kzalloc(size++, gfp)
> - kzalloc_node(size++, gfp, NUMA_NO_NODE)
> - kcalloc(1, size++, gfp)
> - kcalloc_node(1, size++, gfp, NUMA_NO_NODE)
> - kmalloc_array(1, size++, gfp)
> - kmalloc_array_node(1, size++, gfp, NUMA_NO_NODE)
> 
> I've been using the following command to run the tests:
> ./tools/testing/kunit/kunit.py run --kconfig_add CONFIG_FORTIFY_SOURCE=y
> 
> And I've also tried it on x86_64 and arm64 under qemu, with both gcc
> 12.2.0 and clang 14.0.6-2, with the same failures.
> 
> Is there a dependency somewhere I've missed? (I've tried it on the
> ksefltest/kunit branch, with the mentioned dependencies applied, and
> also on your for-next/hardening branch, with the missing patches
> applied.)

I would expect this to pass with v6.1-rc1 when used with the above two
patches added, but it seems those _did_ pass, but not the k*alloc()
helpers for you? That is curious. Here's my testing:

$ ./tools/testing/kunit/kunit.py run --arch x86_64 \
	--kconfig_add CONFIG_FORTIFY_SOURCE=y --make_options LLVM=1 fortify
...
[22:43:32] =================== fortify (3 subtests) ===================
[22:43:32] [PASSED] known_sizes_test
[22:43:32] [PASSED] control_flow_split_test
[22:43:32] [PASSED] alloc_size_test
[22:43:32] ===================== [PASSED] fortify =====================
[22:43:32] ============================================================
[22:43:32] Testing complete. Ran 3 tests: passed: 3
[22:43:32] Elapsed time: 33.210s total, 3.369s configuring, 28.367s
building, 0.799s running

$ clang --version
ClangBuiltLinux clang version 16.0.0 (https://github.com/llvm/llvm-project.git 3291eac12340f465084f347720d99352241f621c)
David Gow Oct. 19, 2022, 6:29 a.m. UTC | #3 
On Wed, Oct 19, 2022 at 1:45 PM Kees Cook <keescook@chromium.org> wrote:
>
> On Wed, Oct 19, 2022 at 11:35:40AM +0800, David Gow wrote:
> > On Tue, Oct 18, 2022 at 4:27 PM Kees Cook <keescook@chromium.org> wrote:
> > >
> > > Validate the effect of the __alloc_size attribute on allocators. If the
> > > compiler doesn't support __builtin_dynamic_object_size(), skip the test.
> > >
> > > Cc: linux-hardening@vger.kernel.org
> > > Signed-off-by: Kees Cook <keescook@chromium.org>
> > > ---
> > > To pass this depends on the following patches:
> > > https://lore.kernel.org/lkml/20221018073430.never.551-kees@kernel.org/
> > > https://lore.kernel.org/lkml/20221018082232.never.213-kees@kernel.org/
> > > To not be skipped, either GCC 12 or Clang is needed.
> > > ---
> >
> > While this _looks_ good, I can't actually get the tests to pass on my
> > machine, with the following all having a
> > __builtin_dynamic_object_size() of -1:
> > - kmalloc_node(size++, gfp, NUMA_NO_NODE)
> > - kzalloc(size++, gfp)
> > - kzalloc_node(size++, gfp, NUMA_NO_NODE)
> > - kcalloc(1, size++, gfp)
> > - kcalloc_node(1, size++, gfp, NUMA_NO_NODE)
> > - kmalloc_array(1, size++, gfp)
> > - kmalloc_array_node(1, size++, gfp, NUMA_NO_NODE)
> >
> > I've been using the following command to run the tests:
> > ./tools/testing/kunit/kunit.py run --kconfig_add CONFIG_FORTIFY_SOURCE=y
> >
> > And I've also tried it on x86_64 and arm64 under qemu, with both gcc
> > 12.2.0 and clang 14.0.6-2, with the same failures.
> >
> > Is there a dependency somewhere I've missed? (I've tried it on the
> > ksefltest/kunit branch, with the mentioned dependencies applied, and
> > also on your for-next/hardening branch, with the missing patches
> > applied.)
>
> I would expect this to pass with v6.1-rc1 when used with the above two
> patches added, but it seems those _did_ pass, but not the k*alloc()
> helpers for you? That is curious. Here's my testing:
>
> $ ./tools/testing/kunit/kunit.py run --arch x86_64 \
>         --kconfig_add CONFIG_FORTIFY_SOURCE=y --make_options LLVM=1 fortify
> ...
> [22:43:32] =================== fortify (3 subtests) ===================
> [22:43:32] [PASSED] known_sizes_test
> [22:43:32] [PASSED] control_flow_split_test
> [22:43:32] [PASSED] alloc_size_test
> [22:43:32] ===================== [PASSED] fortify =====================
> [22:43:32] ============================================================
> [22:43:32] Testing complete. Ran 3 tests: passed: 3
> [22:43:32] Elapsed time: 33.210s total, 3.369s configuring, 28.367s
> building, 0.799s running
>
> $ clang --version
> ClangBuiltLinux clang version 16.0.0 (https://github.com/llvm/llvm-project.git 3291eac12340f465084f347720d99352241f621c)
>
>

Running the exact same command here gives the following output (spam incoming):
[13:55:34] Configuring KUnit Kernel ...
[13:55:34] Building KUnit Kernel ...
Populating config with:
$ make ARCH=x86_64 O=.kunit olddefconfig LLVM=1
Building with:
$ make ARCH=x86_64 O=.kunit --jobs=48 LLVM=1
[13:55:43] Starting KUnit Kernel (1/1)...
[13:55:43] ============================================================
Running tests with:
$ qemu-system-x86_64 -nodefaults -m 1024 -kernel
.kunit/arch/x86/boot/bzImage -append 'kunit.filter_glob=fortify
kunit.enable=1 console=ttyS0 kunit_shutdown=reboot' -no-reboot
-nographic -serial stdio
[13:55:44] =================== fortify (3 subtests) ===================
[13:55:44] [PASSED] known_sizes_test
[13:55:44] [PASSED] control_flow_split_test
[13:55:44] # alloc_size_test: EXPECTATION FAILED at lib/fortify_kunit.c:91
[13:55:44] Expected __builtin_dynamic_object_size(p, 1) == expected, but
[13:55:44] __builtin_dynamic_object_size(p, 1) == -1
[13:55:44] expected == 51
[13:55:44] __alloc_size() not working with kmalloc_node(size++, gfp,
NUMA_NO_NODE)
[13:55:44] # alloc_size_test: EXPECTATION FAILED at lib/fortify_kunit.c:92
[13:55:44] Expected __builtin_dynamic_object_size(p, 1) == expected, but
[13:55:44] __builtin_dynamic_object_size(p, 1) == -1
[13:55:44] expected == 52
[13:55:44] __alloc_size() not working with kzalloc(size++, gfp)
[13:55:44] # alloc_size_test: EXPECTATION FAILED at lib/fortify_kunit.c:93
[13:55:44] Expected __builtin_dynamic_object_size(p, 1) == expected, but
[13:55:44] __builtin_dynamic_object_size(p, 1) == -1
[13:55:44] expected == 53
[13:55:44] __alloc_size() not working with kzalloc_node(size++, gfp,
NUMA_NO_NODE)
[13:55:44] # alloc_size_test: EXPECTATION FAILED at lib/fortify_kunit.c:94
[13:55:44] Expected __builtin_dynamic_object_size(p, 1) == expected, but
[13:55:44] __builtin_dynamic_object_size(p, 1) == -1
[13:55:44] expected == 54
[13:55:44] __alloc_size() not working with kcalloc(1, size++, gfp)
[13:55:44] # alloc_size_test: EXPECTATION FAILED at lib/fortify_kunit.c:95
[13:55:44] Expected __builtin_dynamic_object_size(p, 1) == expected, but
[13:55:44] __builtin_dynamic_object_size(p, 1) == -1
[13:55:44] expected == 55
[13:55:44] __alloc_size() not working with kcalloc_node(1, size++,
gfp, NUMA_NO_NODE)
[13:55:44] # alloc_size_test: EXPECTATION FAILED at lib/fortify_kunit.c:96
[13:55:44] Expected __builtin_dynamic_object_size(p, 1) == expected, but
[13:55:44] __builtin_dynamic_object_size(p, 1) == -1
[13:55:44] expected == 56
[13:55:44] __alloc_size() not working with kmalloc_array(1, size++, gfp)
[13:55:44] # alloc_size_test: EXPECTATION FAILED at lib/fortify_kunit.c:97
[13:55:44] Expected __builtin_dynamic_object_size(p, 1) == expected, but
[13:55:44] __builtin_dynamic_object_size(p, 1) == -1
[13:55:44] expected == 57
[13:55:44] __alloc_size() not working with kmalloc_array_node(1,
size++, gfp, NUMA_NO_NODE)
[13:55:44] not ok 3 - alloc_size_test
[13:55:44] [FAILED] alloc_size_test
[13:55:44] # Subtest: fortify
[13:55:44] 1..3
[13:55:44] # fortify: pass:2 fail:1 skip:0 total:3
[13:55:44] # Totals: pass:2 fail:1 skip:0 total:3
[13:55:44] not ok 1 - fortify
[13:55:44] ===================== [FAILED] fortify =====================
[13:55:44] ============================================================
[13:55:44] Testing complete. Ran 3 tests: passed: 2, failed: 1
[13:55:45] Elapsed time: 10.424s total, 0.002s configuring, 8.950s
building, 0.835s running

With:
clang --version
Debian clang version 14.0.6-2
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin

Same thing with gcc:
gcc (Debian 12.2.0-1) 12.2.0
Copyright (C) 2022 Free Software Foundation, Inc.

I can also reproduce it on a different machine, running openSUSE
Tumbleweed's gcc 12.2 and clang 15.0.2.

It also fails the same way with just the mentioned patches, applied to
torvalds/master at aae803b02f92.

Do you have a specific working tree somewhere public I should try?

-- David
Kees Cook Nov. 1, 2022, 10:04 p.m. UTC | #4 
On Wed, Oct 19, 2022 at 02:29:44PM +0800, David Gow wrote:
> [13:55:44] # alloc_size_test: EXPECTATION FAILED at lib/fortify_kunit.c:91
> [13:55:44] Expected __builtin_dynamic_object_size(p, 1) == expected, but
> [13:55:44] __builtin_dynamic_object_size(p, 1) == -1
> [13:55:44] expected == 51
> [13:55:44] __alloc_size() not working with kmalloc_node(size++, gfp,
> NUMA_NO_NODE)

So, this turned out to be a rat-hole de-ja-vu. The short version is "I
was using Clang 16 where this doesn't manifest", and the long version is
"some inline attributes are broke on all versions of GCC[1] and on Clang
until version 16". :(

I will send the work-around series I've put together to address it. At
the end of the day I now have a WAY more robust set of __alloc_size
KUnit tests. :P

-Kees

[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96503
diff mbox series

Patch

diff --git a/lib/fortify_kunit.c b/lib/fortify_kunit.c
index 409af07f340a..5076ba11adfd 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/string.h>
+#include <linux/slab.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 +63,98 @@  static void control_flow_split_test(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, want_minus_one(pick), SIZE_MAX);
 }
 
+#define check_alloc(alloc, free)	do {				\
+	size_t expected = size;						\
+	void *p = alloc;						\
+	KUNIT_EXPECT_TRUE_MSG(test, p != NULL, #alloc " failed?!\n");	\
+	KUNIT_EXPECT_EQ_MSG(test, __builtin_dynamic_object_size(p, 1),	\
+		expected,						\
+		"__alloc_size() not working with " #alloc "\n");	\
+	free;								\
+} while (0)
+
+static volatile size_t unknown_size = 50;
+
+static void alloc_size_test(struct kunit *test)
+{
+#if !__has_builtin(__builtin_dynamic_object_size)
+	kunit_skip(test, "Compiler is missing __builtin_dynamic_object_size() support\n");
+#else
+	const char device_name[] = "fortify-test";
+	struct device *dev;
+	gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
+	size_t size = unknown_size, prev_size;
+	void *orig;
+
+	/* kmalloc()-family */
+	check_alloc(kmalloc(size++, gfp),			kfree(p));
+	check_alloc(kmalloc_node(size++, gfp, NUMA_NO_NODE),	kfree(p));
+	check_alloc(kzalloc(size++, gfp),			kfree(p));
+	check_alloc(kzalloc_node(size++, gfp, NUMA_NO_NODE),	kfree(p));
+	check_alloc(kcalloc(1, size++, gfp),			kfree(p));
+	check_alloc(kcalloc_node(1, size++, gfp, NUMA_NO_NODE),	kfree(p));
+	check_alloc(kmalloc_array(1, size++, gfp),		kfree(p));
+	check_alloc(kmalloc_array_node(1, size++, gfp, NUMA_NO_NODE), kfree(p));
+	check_alloc(__kmalloc(size++, gfp),			kfree(p));
+	check_alloc(__kmalloc_node(size++, gfp, NUMA_NO_NODE),	kfree(p));
+
+	/* kmemdup() */
+	prev_size = size;
+	size = 11;
+	check_alloc(kmemdup("hello there", size, gfp),		kfree(p));
+	size = prev_size + 1;
+
+	/* krealloc()-family */
+	orig = kmalloc(size++, gfp);
+	check_alloc(krealloc(orig, size++, gfp),		kfree(p));
+	orig = kmalloc(size++, gfp);
+	check_alloc(krealloc_array(orig, 1, size++, gfp),	kfree(p));
+
+	/* vmalloc()-family */
+	check_alloc(vmalloc(size++),				vfree(p));
+	check_alloc(vzalloc(size++),				vfree(p));
+	check_alloc(__vmalloc(size++, gfp),			vfree(p));
+
+	/* kvalloc()-family */
+	check_alloc(kvmalloc(size++, gfp),			kvfree(p));
+	check_alloc(kvmalloc_node(size++, gfp, NUMA_NO_NODE),	kvfree(p));
+	check_alloc(kvzalloc(size++, gfp),			kvfree(p));
+	check_alloc(kvzalloc_node(size++, gfp, NUMA_NO_NODE),	kvfree(p));
+	check_alloc(kvcalloc(1, size++, gfp),			kvfree(p));
+	check_alloc(kvmalloc_array(1, size++, gfp),		kvfree(p));
+
+	/* kvrealloc() */
+	prev_size = size++;
+	orig = kvmalloc(prev_size, gfp);
+	check_alloc(kvrealloc(orig, prev_size, size++, gfp),	kfree(p));
+
+	/* Create dummy device for devm_kmalloc()-family tests. */
+	dev = root_device_register(device_name);
+	KUNIT_ASSERT_FALSE_MSG(test, IS_ERR(dev),
+			       "Cannot register test device\n");
+
+	/* devm_kmalloc()-family */
+	check_alloc(devm_kmalloc(dev, size++, gfp),		devm_kfree(dev, p));
+	check_alloc(devm_kzalloc(dev, size++, gfp),		devm_kfree(dev, p));
+
+	/* devm_kmemdup() */
+	prev_size = size;
+	size = 4;
+	check_alloc(devm_kmemdup(dev, "Ohai", size, gfp),	devm_kfree(dev, p));
+	size = prev_size + 1;
+
+	/* devm_kremalloc() */
+	orig = devm_kmalloc(dev, size++, gfp);
+	check_alloc(devm_krealloc(dev, orig, size++, gfp),	devm_kfree(dev, p));
+
+	device_unregister(dev);
+#endif
+}
+
 static struct kunit_case fortify_test_cases[] = {
 	KUNIT_CASE(known_sizes_test),
 	KUNIT_CASE(control_flow_split_test),
+	KUNIT_CASE(alloc_size_test),
 	{}
 };