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From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, andreyknvl@google.com,
	davidgow@google.com, linux-mm@kvack.org,
	mm-commits@vger.kernel.org, torvalds@linux-foundation.org
Subject: [patch 05/15] kasan: adopt KUNIT tests to SW_TAGS mode
Date: Sun, 01 Nov 2020 17:07:37 -0800	[thread overview]
Message-ID: <20201102010737.6S4Uo6WPN%akpm@linux-foundation.org> (raw)
In-Reply-To: <20201101170656.48abbd5e88375219f868af5e@linux-foundation.org>

From: Andrey Konovalov <andreyknvl@google.com>
Subject: kasan: adopt KUNIT tests to SW_TAGS mode

Now that we have KASAN-KUNIT tests integration, it's easy to see that some
KASAN tests are not adopted to the SW_TAGS mode and are failing.

Adjust the allocation size for kasan_memchr() and kasan_memcmp() by roung
it up to OOB_TAG_OFF so the bad access ends up in a separate memory
granule.

Add a new kmalloc_uaf_16() tests that relies on UAF, and a new
kasan_bitops_tags() test that is tailored to tag-based mode, as it's hard
to adopt the existing kmalloc_oob_16() and kasan_bitops_generic() (renamed
from kasan_bitops()) without losing the precision.

Add new kmalloc_uaf_16() and kasan_bitops_uaf() tests that rely on UAFs,
as it's hard to adopt the existing kmalloc_oob_16() and kasan_bitops_oob()
(rename from kasan_bitops()) without losing the precision.

Disable kasan_global_oob() and kasan_alloca_oob_left/right() as SW_TAGS
mode doesn't instrument globals nor dynamic allocas.

Link: https://lkml.kernel.org/r/76eee17b6531ca8b3ca92b240cb2fd23204aaff7.1603129942.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: David Gow <davidgow@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/test_kasan.c |  149 ++++++++++++++++++++++++++++++++-------------
 1 file changed, 107 insertions(+), 42 deletions(-)

--- a/lib/test_kasan.c~kasan-adopt-kunit-tests-to-sw_tags-mode
+++ a/lib/test_kasan.c
@@ -216,6 +216,12 @@ static void kmalloc_oob_16(struct kunit
 		u64 words[2];
 	} *ptr1, *ptr2;
 
+	/* This test is specifically crafted for the generic mode. */
+	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+		kunit_info(test, "CONFIG_KASAN_GENERIC required\n");
+		return;
+	}
+
 	ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1);
 
@@ -227,6 +233,23 @@ static void kmalloc_oob_16(struct kunit
 	kfree(ptr2);
 }
 
+static void kmalloc_uaf_16(struct kunit *test)
+{
+	struct {
+		u64 words[2];
+	} *ptr1, *ptr2;
+
+	ptr1 = kmalloc(sizeof(*ptr1), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1);
+
+	ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2);
+	kfree(ptr2);
+
+	KUNIT_EXPECT_KASAN_FAIL(test, *ptr1 = *ptr2);
+	kfree(ptr1);
+}
+
 static void kmalloc_oob_memset_2(struct kunit *test)
 {
 	char *ptr;
@@ -429,6 +452,12 @@ static void kasan_global_oob(struct kuni
 	volatile int i = 3;
 	char *p = &global_array[ARRAY_SIZE(global_array) + i];
 
+	/* Only generic mode instruments globals. */
+	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+		kunit_info(test, "CONFIG_KASAN_GENERIC required");
+		return;
+	}
+
 	KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p);
 }
 
@@ -467,6 +496,12 @@ static void kasan_alloca_oob_left(struct
 	char alloca_array[i];
 	char *p = alloca_array - 1;
 
+	/* Only generic mode instruments dynamic allocas. */
+	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+		kunit_info(test, "CONFIG_KASAN_GENERIC required");
+		return;
+	}
+
 	if (!IS_ENABLED(CONFIG_KASAN_STACK)) {
 		kunit_info(test, "CONFIG_KASAN_STACK is not enabled");
 		return;
@@ -481,6 +516,12 @@ static void kasan_alloca_oob_right(struc
 	char alloca_array[i];
 	char *p = alloca_array + i;
 
+	/* Only generic mode instruments dynamic allocas. */
+	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+		kunit_info(test, "CONFIG_KASAN_GENERIC required");
+		return;
+	}
+
 	if (!IS_ENABLED(CONFIG_KASAN_STACK)) {
 		kunit_info(test, "CONFIG_KASAN_STACK is not enabled");
 		return;
@@ -551,6 +592,9 @@ static void kasan_memchr(struct kunit *t
 		return;
 	}
 
+	if (OOB_TAG_OFF)
+		size = round_up(size, OOB_TAG_OFF);
+
 	ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
 
@@ -573,6 +617,9 @@ static void kasan_memcmp(struct kunit *t
 		return;
 	}
 
+	if (OOB_TAG_OFF)
+		size = round_up(size, OOB_TAG_OFF);
+
 	ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
 	memset(arr, 0, sizeof(arr));
@@ -619,13 +666,50 @@ static void kasan_strings(struct kunit *
 	KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = strnlen(ptr, 1));
 }
 
-static void kasan_bitops(struct kunit *test)
+static void kasan_bitops_modify(struct kunit *test, int nr, void *addr)
+{
+	KUNIT_EXPECT_KASAN_FAIL(test, set_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, __set_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, clear_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, clear_bit_unlock(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit_unlock(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, change_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, __change_bit(nr, addr));
+}
+
+static void kasan_bitops_test_and_modify(struct kunit *test, int nr, void *addr)
+{
+	KUNIT_EXPECT_KASAN_FAIL(test, test_and_set_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, __test_and_set_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, test_and_set_bit_lock(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, test_and_clear_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, __test_and_clear_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, test_and_change_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, __test_and_change_bit(nr, addr));
+	KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = test_bit(nr, addr));
+
+#if defined(clear_bit_unlock_is_negative_byte)
+	KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result =
+				clear_bit_unlock_is_negative_byte(nr, addr));
+#endif
+}
+
+static void kasan_bitops_generic(struct kunit *test)
 {
+	long *bits;
+
+	/* This test is specifically crafted for the generic mode. */
+	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+		kunit_info(test, "CONFIG_KASAN_GENERIC required\n");
+		return;
+	}
+
 	/*
 	 * Allocate 1 more byte, which causes kzalloc to round up to 16-bytes;
 	 * this way we do not actually corrupt other memory.
 	 */
-	long *bits = kzalloc(sizeof(*bits) + 1, GFP_KERNEL);
+	bits = kzalloc(sizeof(*bits) + 1, GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bits);
 
 	/*
@@ -633,55 +717,34 @@ static void kasan_bitops(struct kunit *t
 	 * below accesses are still out-of-bounds, since bitops are defined to
 	 * operate on the whole long the bit is in.
 	 */
-	KUNIT_EXPECT_KASAN_FAIL(test, set_bit(BITS_PER_LONG, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test, __set_bit(BITS_PER_LONG, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test, clear_bit(BITS_PER_LONG, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit(BITS_PER_LONG, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test, clear_bit_unlock(BITS_PER_LONG, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit_unlock(BITS_PER_LONG, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test, change_bit(BITS_PER_LONG, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test, __change_bit(BITS_PER_LONG, bits));
+	kasan_bitops_modify(test, BITS_PER_LONG, bits);
 
 	/*
 	 * Below calls try to access bit beyond allocated memory.
 	 */
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		test_and_set_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		__test_and_set_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));
+	kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, bits);
 
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		test_and_set_bit_lock(BITS_PER_LONG + BITS_PER_BYTE, bits));
-
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		test_and_clear_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));
+	kfree(bits);
+}
 
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		__test_and_clear_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));
+static void kasan_bitops_tags(struct kunit *test)
+{
+	long *bits;
 
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		test_and_change_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));
+	/* This test is specifically crafted for the tag-based mode. */
+	if (IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+		kunit_info(test, "CONFIG_KASAN_SW_TAGS required\n");
+		return;
+	}
 
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		__test_and_change_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));
+	/* Allocation size will be rounded to up granule size, which is 16. */
+	bits = kzalloc(sizeof(*bits), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bits);
 
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		kasan_int_result =
-			test_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));
+	/* Do the accesses past the 16 allocated bytes. */
+	kasan_bitops_modify(test, BITS_PER_LONG, &bits[1]);
+	kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, &bits[1]);
 
-#if defined(clear_bit_unlock_is_negative_byte)
-	KUNIT_EXPECT_KASAN_FAIL(test,
-		kasan_int_result = clear_bit_unlock_is_negative_byte(
-			BITS_PER_LONG + BITS_PER_BYTE, bits));
-#endif
 	kfree(bits);
 }
 
@@ -728,6 +791,7 @@ static struct kunit_case kasan_kunit_tes
 	KUNIT_CASE(kmalloc_oob_krealloc_more),
 	KUNIT_CASE(kmalloc_oob_krealloc_less),
 	KUNIT_CASE(kmalloc_oob_16),
+	KUNIT_CASE(kmalloc_uaf_16),
 	KUNIT_CASE(kmalloc_oob_in_memset),
 	KUNIT_CASE(kmalloc_oob_memset_2),
 	KUNIT_CASE(kmalloc_oob_memset_4),
@@ -751,7 +815,8 @@ static struct kunit_case kasan_kunit_tes
 	KUNIT_CASE(kasan_memchr),
 	KUNIT_CASE(kasan_memcmp),
 	KUNIT_CASE(kasan_strings),
-	KUNIT_CASE(kasan_bitops),
+	KUNIT_CASE(kasan_bitops_generic),
+	KUNIT_CASE(kasan_bitops_tags),
 	KUNIT_CASE(kmalloc_double_kzfree),
 	KUNIT_CASE(vmalloc_oob),
 	{}
_


  parent reply	other threads:[~2020-11-02  1:07 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-02  1:06 incoming Andrew Morton
2020-11-02  1:07 ` [patch 01/15] mm/mremap_pages: fix static key devmap_managed_key updates Andrew Morton
2020-11-02  1:07 ` [patch 02/15] hugetlb_cgroup: fix reservation accounting Andrew Morton
2020-11-02  1:07 ` [patch 03/15] mm: memcontrol: correct the NR_ANON_THPS counter of hierarchical memcg Andrew Morton
2020-11-02  1:07 ` [patch 04/15] mm: memcg: link page counters to root if use_hierarchy is false Andrew Morton
2020-11-02  1:07 ` Andrew Morton [this message]
2020-11-02  1:07 ` [patch 06/15] mm: mempolicy: fix potential pte_unmap_unlock pte error Andrew Morton
2020-11-02  1:07 ` [patch 07/15] ptrace: fix task_join_group_stop() for the case when current is traced Andrew Morton
2020-11-02  1:07 ` [patch 08/15] lib/crc32test: remove extra local_irq_disable/enable Andrew Morton
2020-11-02  1:07 ` [patch 09/15] mm/truncate.c: make __invalidate_mapping_pages() static Andrew Morton
2020-11-02  1:07 ` [patch 10/15] kthread_worker: prevent queuing delayed work from timer_fn when it is being canceled Andrew Morton
2020-11-02  1:07 ` [patch 11/15] mm, oom: keep oom_adj under or at upper limit when printing Andrew Morton
2020-11-02  1:08 ` [patch 12/15] mm: always have io_remap_pfn_range() set pgprot_decrypted() Andrew Morton
2020-11-02  1:08 ` [patch 13/15] epoll: check ep_events_available() upon timeout Andrew Morton
2020-11-02 17:08   ` Linus Torvalds
2020-11-02 17:48     ` Soheil Hassas Yeganeh
2020-11-02 18:51       ` Linus Torvalds
2020-11-02 19:38         ` Linus Torvalds
2020-11-02 19:54         ` Soheil Hassas Yeganeh
2020-11-02 20:12           ` Linus Torvalds
2020-11-02  1:08 ` [patch 14/15] epoll: add a selftest for epoll timeout race Andrew Morton
2020-11-02  1:08 ` [patch 15/15] kernel/hung_task.c: make type annotations consistent Andrew Morton

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