* [PATCH] kasan: test: Silence allocation warnings from GCC 12
@ 2022-02-13 18:32 Kees Cook
2022-02-16 15:26 ` Andrey Konovalov
0 siblings, 1 reply; 3+ messages in thread
From: Kees Cook @ 2022-02-13 18:32 UTC (permalink / raw)
To: Andrey Ryabinin
Cc: Kees Cook, Alexander Potapenko, Andrey Konovalov, Dmitry Vyukov,
kasan-dev, linux-kernel, linux-hardening
GCC 12 is able to see more problems with allocation sizes at compile
time, so these must be silenced so the runtime checks will still be
available. Use OPTIMIZER_HIDE_VAR() to silence the new warnings:
lib/test_kasan.c: In function 'ksize_uaf':
lib/test_kasan.c:781:61: warning: array subscript 120 is outside array bounds of 'void[120]' [-Warray-bounds]
781 | KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size]);
| ~~~~~~~~~~~~~~~~~~~~~~^~~~~~
lib/test_kasan.c:96:9: note: in definition of macro 'KUNIT_EXPECT_KASAN_FAIL'
96 | expression; \
| ^~~~~~~~~~
In function 'kmalloc',
inlined from 'ksize_uaf' at lib/test_kasan.c:775:8:
./include/linux/slab.h:581:24: note: at offset 120 into object of size 120 allocated by 'kmem_cache_alloc_trace'
581 | return kmem_cache_alloc_trace(
| ^~~~~~~~~~~~~~~~~~~~~~~
582 | kmalloc_caches[kmalloc_type(flags)][index],
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
583 | flags, size);
| ~~~~~~~~~~~~
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: kasan-dev@googlegroups.com
Signed-off-by: Kees Cook <keescook@chromium.org>
---
lib/test_kasan.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 26a5c9007653..a19b3d608e3e 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -124,6 +124,7 @@ static void kmalloc_oob_right(struct kunit *test)
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(ptr);
/*
* An unaligned access past the requested kmalloc size.
@@ -185,6 +186,7 @@ static void kmalloc_pagealloc_oob_right(struct kunit *test)
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(ptr);
KUNIT_EXPECT_KASAN_FAIL(test, ptr[size + OOB_TAG_OFF] = 0);
kfree(ptr);
@@ -265,6 +267,7 @@ static void kmalloc_large_oob_right(struct kunit *test)
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(ptr);
KUNIT_EXPECT_KASAN_FAIL(test, ptr[size] = 0);
kfree(ptr);
}
@@ -748,6 +751,7 @@ static void ksize_unpoisons_memory(struct kunit *test)
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(ptr);
real_size = ksize(ptr);
/* This access shouldn't trigger a KASAN report. */
--
2.30.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] kasan: test: Silence allocation warnings from GCC 12
2022-02-13 18:32 [PATCH] kasan: test: Silence allocation warnings from GCC 12 Kees Cook
@ 2022-02-16 15:26 ` Andrey Konovalov
2022-02-16 16:22 ` Kees Cook
0 siblings, 1 reply; 3+ messages in thread
From: Andrey Konovalov @ 2022-02-16 15:26 UTC (permalink / raw)
To: Kees Cook
Cc: Andrey Ryabinin, Alexander Potapenko, Dmitry Vyukov, kasan-dev,
LKML, linux-hardening
On Sun, Feb 13, 2022 at 7:32 PM Kees Cook <keescook@chromium.org> wrote:
>
> GCC 12 is able to see more problems with allocation sizes at compile
> time, so these must be silenced so the runtime checks will still be
> available. Use OPTIMIZER_HIDE_VAR() to silence the new warnings:
>
> lib/test_kasan.c: In function 'ksize_uaf':
Hm, the warning mentions ksize_uaf, but none of the changes touch it.
> lib/test_kasan.c:781:61: warning: array subscript 120 is outside array bounds of 'void[120]' [-Warray-bounds]
> 781 | KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size]);
> | ~~~~~~~~~~~~~~~~~~~~~~^~~~~~
> lib/test_kasan.c:96:9: note: in definition of macro 'KUNIT_EXPECT_KASAN_FAIL'
> 96 | expression; \
> | ^~~~~~~~~~
> In function 'kmalloc',
> inlined from 'ksize_uaf' at lib/test_kasan.c:775:8:
> ./include/linux/slab.h:581:24: note: at offset 120 into object of size 120 allocated by 'kmem_cache_alloc_trace'
> 581 | return kmem_cache_alloc_trace(
> | ^~~~~~~~~~~~~~~~~~~~~~~
> 582 | kmalloc_caches[kmalloc_type(flags)][index],
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 583 | flags, size);
> | ~~~~~~~~~~~~
>
> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
> Cc: Alexander Potapenko <glider@google.com>
> Cc: Andrey Konovalov <andreyknvl@gmail.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Cc: kasan-dev@googlegroups.com
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> lib/test_kasan.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> index 26a5c9007653..a19b3d608e3e 100644
> --- a/lib/test_kasan.c
> +++ b/lib/test_kasan.c
> @@ -124,6 +124,7 @@ static void kmalloc_oob_right(struct kunit *test)
>
> ptr = kmalloc(size, GFP_KERNEL);
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> + OPTIMIZER_HIDE_VAR(ptr);
>
> /*
> * An unaligned access past the requested kmalloc size.
> @@ -185,6 +186,7 @@ static void kmalloc_pagealloc_oob_right(struct kunit *test)
> ptr = kmalloc(size, GFP_KERNEL);
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
>
> + OPTIMIZER_HIDE_VAR(ptr);
> KUNIT_EXPECT_KASAN_FAIL(test, ptr[size + OOB_TAG_OFF] = 0);
>
> kfree(ptr);
> @@ -265,6 +267,7 @@ static void kmalloc_large_oob_right(struct kunit *test)
> ptr = kmalloc(size, GFP_KERNEL);
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
>
> + OPTIMIZER_HIDE_VAR(ptr);
> KUNIT_EXPECT_KASAN_FAIL(test, ptr[size] = 0);
> kfree(ptr);
> }
> @@ -748,6 +751,7 @@ static void ksize_unpoisons_memory(struct kunit *test)
>
> ptr = kmalloc(size, GFP_KERNEL);
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> + OPTIMIZER_HIDE_VAR(ptr);
> real_size = ksize(ptr);
>
> /* This access shouldn't trigger a KASAN report. */
> --
> 2.30.2
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] kasan: test: Silence allocation warnings from GCC 12
2022-02-16 15:26 ` Andrey Konovalov
@ 2022-02-16 16:22 ` Kees Cook
0 siblings, 0 replies; 3+ messages in thread
From: Kees Cook @ 2022-02-16 16:22 UTC (permalink / raw)
To: Andrey Konovalov
Cc: Andrey Ryabinin, Alexander Potapenko, Dmitry Vyukov, kasan-dev,
LKML, linux-hardening
On Wed, Feb 16, 2022 at 04:26:46PM +0100, Andrey Konovalov wrote:
> On Sun, Feb 13, 2022 at 7:32 PM Kees Cook <keescook@chromium.org> wrote:
> >
> > GCC 12 is able to see more problems with allocation sizes at compile
> > time, so these must be silenced so the runtime checks will still be
> > available. Use OPTIMIZER_HIDE_VAR() to silence the new warnings:
> >
> > lib/test_kasan.c: In function 'ksize_uaf':
>
> Hm, the warning mentions ksize_uaf, but none of the changes touch it.
Excellent point -- let me go re-test this.
-Kees
>
> > lib/test_kasan.c:781:61: warning: array subscript 120 is outside array bounds of 'void[120]' [-Warray-bounds]
> > 781 | KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size]);
> > | ~~~~~~~~~~~~~~~~~~~~~~^~~~~~
> > lib/test_kasan.c:96:9: note: in definition of macro 'KUNIT_EXPECT_KASAN_FAIL'
> > 96 | expression; \
> > | ^~~~~~~~~~
> > In function 'kmalloc',
> > inlined from 'ksize_uaf' at lib/test_kasan.c:775:8:
> > ./include/linux/slab.h:581:24: note: at offset 120 into object of size 120 allocated by 'kmem_cache_alloc_trace'
> > 581 | return kmem_cache_alloc_trace(
> > | ^~~~~~~~~~~~~~~~~~~~~~~
> > 582 | kmalloc_caches[kmalloc_type(flags)][index],
> > | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > 583 | flags, size);
> > | ~~~~~~~~~~~~
> >
> > Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
> > Cc: Alexander Potapenko <glider@google.com>
> > Cc: Andrey Konovalov <andreyknvl@gmail.com>
> > Cc: Dmitry Vyukov <dvyukov@google.com>
> > Cc: kasan-dev@googlegroups.com
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> > lib/test_kasan.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> > index 26a5c9007653..a19b3d608e3e 100644
> > --- a/lib/test_kasan.c
> > +++ b/lib/test_kasan.c
> > @@ -124,6 +124,7 @@ static void kmalloc_oob_right(struct kunit *test)
> >
> > ptr = kmalloc(size, GFP_KERNEL);
> > KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> > + OPTIMIZER_HIDE_VAR(ptr);
> >
> > /*
> > * An unaligned access past the requested kmalloc size.
> > @@ -185,6 +186,7 @@ static void kmalloc_pagealloc_oob_right(struct kunit *test)
> > ptr = kmalloc(size, GFP_KERNEL);
> > KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> >
> > + OPTIMIZER_HIDE_VAR(ptr);
> > KUNIT_EXPECT_KASAN_FAIL(test, ptr[size + OOB_TAG_OFF] = 0);
> >
> > kfree(ptr);
> > @@ -265,6 +267,7 @@ static void kmalloc_large_oob_right(struct kunit *test)
> > ptr = kmalloc(size, GFP_KERNEL);
> > KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> >
> > + OPTIMIZER_HIDE_VAR(ptr);
> > KUNIT_EXPECT_KASAN_FAIL(test, ptr[size] = 0);
> > kfree(ptr);
> > }
> > @@ -748,6 +751,7 @@ static void ksize_unpoisons_memory(struct kunit *test)
> >
> > ptr = kmalloc(size, GFP_KERNEL);
> > KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> > + OPTIMIZER_HIDE_VAR(ptr);
> > real_size = ksize(ptr);
> >
> > /* This access shouldn't trigger a KASAN report. */
> > --
> > 2.30.2
> >
--
Kees Cook
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-02-13 18:32 [PATCH] kasan: test: Silence allocation warnings from GCC 12 Kees Cook
2022-02-16 15:26 ` Andrey Konovalov
2022-02-16 16:22 ` Kees Cook
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