This is a note to let you know that I've just added the patch titled
kasan: test: Silence GCC 12 warnings
to the 5.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kasan-test-silence-gcc-12-warnings.patch
and it can be found in the queue-5.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 19a747206b86cb332c58ccd1c8e13faf5b46321f
Author: Kees Cook <keescook@xxxxxxxxxxxx>
Date: Wed Jun 8 14:40:24 2022 -0700
kasan: test: Silence GCC 12 warnings
[ Upstream commit aaf50b1969d7933a51ea421b11432a7fb90974e3 ]
GCC 12 continues to get smarter about array accesses. The KASAN tests
are expecting to explicitly test out-of-bounds conditions at run-time,
so hide the variable from GCC, to avoid warnings like:
../lib/test_kasan.c: In function 'ksize_uaf':
../lib/test_kasan.c:790:61: warning: array subscript 120 is outside array bounds of 'void[120]' [-Warray-bounds]
790 | KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size]);
| ~~~~~~~~~~~~~~~~~~~~~~^~~~~~
../lib/test_kasan.c:97:9: note: in definition of macro 'KUNIT_EXPECT_KASAN_FAIL'
97 | expression; \
| ^~~~~~~~~~
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: kasan-dev@xxxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220608214024.1068451-1-keescook@xxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index c233b1a4e984..58c1b01ccfe2 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -131,6 +131,7 @@ 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.
* Only generic KASAN can precisely detect these.
@@ -159,6 +160,7 @@ static void kmalloc_oob_left(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 = *(ptr - 1));
kfree(ptr);
}
@@ -171,6 +173,7 @@ static void kmalloc_node_oob_right(struct kunit *test)
ptr = kmalloc_node(size, GFP_KERNEL, 0);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(ptr);
KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = ptr[size]);
kfree(ptr);
}
@@ -191,6 +194,7 @@ 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);
@@ -271,6 +275,7 @@ 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);
}
@@ -410,6 +415,8 @@ static void kmalloc_oob_16(struct kunit *test)
ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2);
+ OPTIMIZER_HIDE_VAR(ptr1);
+ OPTIMIZER_HIDE_VAR(ptr2);
KUNIT_EXPECT_KASAN_FAIL(test, *ptr1 = *ptr2);
kfree(ptr1);
kfree(ptr2);
@@ -756,6 +763,8 @@ static void ksize_unpoisons_memory(struct kunit *test)
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
real_size = ksize(ptr);
+ OPTIMIZER_HIDE_VAR(ptr);
+
/* This access shouldn't trigger a KASAN report. */
ptr[size] = 'x';
@@ -778,6 +787,7 @@ static void ksize_uaf(struct kunit *test)
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
kfree(ptr);
+ OPTIMIZER_HIDE_VAR(ptr);
KUNIT_EXPECT_KASAN_FAIL(test, ksize(ptr));
KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[0]);
KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size]);
