The patch titled
Subject: kunit: kasan_test: disable fortify string checker on kmalloc_oob_memset
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
kunit-kasan_test-disable-fortify-string-checker-on-kmalloc_oob_memset.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kunit-kasan_test-disable-fortify-string-checker-on-kmalloc_oob_memset.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Nico Pache <npache@xxxxxxxxxx>
Subject: kunit: kasan_test: disable fortify string checker on kmalloc_oob_memset
Date: Tue, 12 Dec 2023 16:26:59 -0700
Similar to commit 09c6304e38e4 ("kasan: test: fix compatibility with
FORTIFY_SOURCE") the kernel is panicing in kmalloc_oob_memset_*.
This is due to the `ptr` not being hidden from the optimizer which would
disable the runtime fortify string checker.
kernel BUG at lib/string_helpers.c:1048!
Call Trace:
[<00000000272502e2>] fortify_panic+0x2a/0x30
([<00000000272502de>] fortify_panic+0x26/0x30)
[<001bffff817045c4>] kmalloc_oob_memset_2+0x22c/0x230 [kasan_test]
Hide the `ptr` variable from the optimizer to fix the kernel panic. Also
define a size2 variable and hide that as well. This cleans up the code
and follows the same convention as other tests.
Link: https://lkml.kernel.org/r/20231212232659.18839-1-npache@xxxxxxxxxx
Signed-off-by: Nico Pache <npache@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/kasan/kasan_test.c | 20 ++++++++++++++++----
1 file changed, 16 insertions(+), 4 deletions(-)
--- a/mm/kasan/kasan_test.c~kunit-kasan_test-disable-fortify-string-checker-on-kmalloc_oob_memset
+++ a/mm/kasan/kasan_test.c
@@ -493,14 +493,17 @@ static void kmalloc_oob_memset_2(struct
{
char *ptr;
size_t size = 128 - KASAN_GRANULE_SIZE;
+ size_t size2 = 2;
KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test);
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(ptr);
OPTIMIZER_HIDE_VAR(size);
- KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 1, 0, 2));
+ OPTIMIZER_HIDE_VAR(size2);
+ KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 1, 0, size2));
kfree(ptr);
}
@@ -508,14 +511,17 @@ static void kmalloc_oob_memset_4(struct
{
char *ptr;
size_t size = 128 - KASAN_GRANULE_SIZE;
+ size_t size2 = 4;
KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test);
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(ptr);
OPTIMIZER_HIDE_VAR(size);
- KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 3, 0, 4));
+ OPTIMIZER_HIDE_VAR(size2);
+ KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 3, 0, size2));
kfree(ptr);
}
@@ -523,14 +529,17 @@ static void kmalloc_oob_memset_8(struct
{
char *ptr;
size_t size = 128 - KASAN_GRANULE_SIZE;
+ size_t size2 = 8;
KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test);
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(ptr);
OPTIMIZER_HIDE_VAR(size);
- KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 7, 0, 8));
+ OPTIMIZER_HIDE_VAR(size2);
+ KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 7, 0, size2));
kfree(ptr);
}
@@ -538,14 +547,17 @@ static void kmalloc_oob_memset_16(struct
{
char *ptr;
size_t size = 128 - KASAN_GRANULE_SIZE;
+ size_t size2 = 16;
KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test);
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(ptr);
OPTIMIZER_HIDE_VAR(size);
- KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 15, 0, 16));
+ OPTIMIZER_HIDE_VAR(size2);
+ KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 15, 0, size2));
kfree(ptr);
}
_
Patches currently in -mm which might be from npache@xxxxxxxxxx are
kunit-kasan_test-disable-fortify-string-checker-on-kmalloc_oob_memset.patch
