From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, andreyknvl@gmail.com,
brendanhiggins@google.com, dvyukov@google.com, elver@google.com,
glider@google.com, keescook@chromium.org, linux-mm@kvack.org,
mm-commits@vger.kernel.org, npache@redhat.com,
ryabinin.a.a@gmail.com, torvalds@linux-foundation.org
Subject: [patch 07/12] kasan: test: fix compatibility with FORTIFY_SOURCE
Date: Sat, 29 Jan 2022 13:41:11 -0800 [thread overview]
Message-ID: <20220129214111.2i2Jilwui%akpm@linux-foundation.org> (raw)
In-Reply-To: <20220129134026.8ccf701012f26eb2c2c269c9@linux-foundation.org>
From: Marco Elver <elver@google.com>
Subject: kasan: test: fix compatibility with FORTIFY_SOURCE
With CONFIG_FORTIFY_SOURCE enabled, string functions will also perform
dynamic checks using __builtin_object_size(ptr), which when failed will
panic the kernel.
Because the KASAN test deliberately performs out-of-bounds operations, the
kernel panics with FORTIFY_SOURCE, for example:
| kernel BUG at lib/string_helpers.c:910!
| invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
| CPU: 1 PID: 137 Comm: kunit_try_catch Tainted: G B 5.16.0-rc3+ #3
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
| RIP: 0010:fortify_panic+0x19/0x1b
| ...
| Call Trace:
| <TASK>
| kmalloc_oob_in_memset.cold+0x16/0x16
| ...
Fix it by also hiding `ptr` from the optimizer, which will ensure that
__builtin_object_size() does not return a valid size, preventing fortified
string functions from panicking.
Link: https://lkml.kernel.org/r/20220124160744.1244685-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Reported-by: Nico Pache <npache@redhat.com>
Reviewed-by: Nico Pache <npache@redhat.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
lib/test_kasan.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/lib/test_kasan.c~kasan-test-fix-compatibility-with-fortify_source
+++ a/lib/test_kasan.c
@@ -492,6 +492,7 @@ static void kmalloc_oob_in_memset(struct
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, 0, size + KASAN_GRANULE_SIZE));
@@ -515,6 +516,7 @@ static void kmalloc_memmove_negative_siz
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
memset((char *)ptr, 0, 64);
+ OPTIMIZER_HIDE_VAR(ptr);
OPTIMIZER_HIDE_VAR(invalid_size);
KUNIT_EXPECT_KASAN_FAIL(test,
memmove((char *)ptr, (char *)ptr + 4, invalid_size));
@@ -531,6 +533,7 @@ static void kmalloc_memmove_invalid_size
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
memset((char *)ptr, 0, 64);
+ OPTIMIZER_HIDE_VAR(ptr);
KUNIT_EXPECT_KASAN_FAIL(test,
memmove((char *)ptr, (char *)ptr + 4, invalid_size));
kfree(ptr);
@@ -893,6 +896,7 @@ static void kasan_memchr(struct kunit *t
ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(ptr);
OPTIMIZER_HIDE_VAR(size);
KUNIT_EXPECT_KASAN_FAIL(test,
kasan_ptr_result = memchr(ptr, '1', size + 1));
@@ -919,6 +923,7 @@ static void kasan_memcmp(struct kunit *t
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
memset(arr, 0, sizeof(arr));
+ OPTIMIZER_HIDE_VAR(ptr);
OPTIMIZER_HIDE_VAR(size);
KUNIT_EXPECT_KASAN_FAIL(test,
kasan_int_result = memcmp(ptr, arr, size+1));
_
next prev parent reply other threads:[~2022-01-29 21:41 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-29 21:40 incoming Andrew Morton
2022-01-29 21:40 ` [patch 01/12] include/linux/sysctl.h: fix register_sysctl_mount_point() return type Andrew Morton
2022-01-29 21:40 ` [patch 02/12] binfmt_misc: fix crash when load/unload module Andrew Morton
2022-01-29 21:40 ` [patch 03/12] ia64: make IA64_MCA_RECOVERY bool instead of tristate Andrew Morton
2022-01-29 21:41 ` [patch 04/12] memory-failure: fetch compound_head after pgmap_pfn_valid() Andrew Morton
2022-01-29 21:41 ` [patch 05/12] mm: page->mapping folio->mapping should have the same offset Andrew Morton
2022-01-29 21:41 ` [patch 06/12] tools/testing/scatterlist: add missing defines Andrew Morton
2022-01-29 21:41 ` Andrew Morton [this message]
2022-01-29 21:41 ` [patch 08/12] mm, kasan: use compare-exchange operation to set KASAN page tag Andrew Morton
2022-01-29 21:41 ` [patch 09/12] psi: fix "no previous prototype" warnings when CONFIG_CGROUPS=n Andrew Morton
2022-01-29 21:41 ` [patch 10/12] psi: fix "defined but not used" warnings when CONFIG_PROC_FS=n Andrew Morton
2022-01-29 21:41 ` [patch 11/12] jbd2: export jbd2_journal_[grab|put]_journal_head Andrew Morton
2022-01-29 21:41 ` [patch 12/12] ocfs2: fix a deadlock when commit trans Andrew Morton
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