diff mbox series

[143/212] kasan: test: avoid writing invalid memory

Message ID 20210902215735.v8iHp51ea%akpm@linux-foundation.org (mailing list archive)
State New
Headers show
Series [001/212] ia64: fix typo in a comment | expand

Commit Message

Andrew Morton Sept. 2, 2021, 9:57 p.m. UTC 
From: Andrey Konovalov <andreyknvl@gmail.com>
Subject: kasan: test: avoid writing invalid memory

Multiple KASAN tests do writes past the allocated objects or writes to
freed memory.  Turn these writes into reads to avoid corrupting memory. 
Otherwise, these tests might lead to crashes with the HW_TAGS mode, as it
neither uses quarantine nor redzones.

Link: https://lkml.kernel.org/r/c3cd2a383e757e27dd9131635fc7d09a48a49cf9.1628779805.git.andreyknvl@gmail.com
Signed-off-by: Andrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/test_kasan.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)
diff mbox series

Patch

--- a/lib/test_kasan.c~kasan-test-avoid-writing-invalid-memory
+++ a/lib/test_kasan.c
@@ -167,7 +167,7 @@  static void kmalloc_node_oob_right(struc
 	ptr = kmalloc_node(size, GFP_KERNEL, 0);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
 
-	KUNIT_EXPECT_KASAN_FAIL(test, ptr[size] = 0);
+	KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = ptr[size]);
 	kfree(ptr);
 }
 
@@ -203,7 +203,7 @@  static void kmalloc_pagealloc_uaf(struct
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
 	kfree(ptr);
 
-	KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = 0);
+	KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[0]);
 }
 
 static void kmalloc_pagealloc_invalid_free(struct kunit *test)
@@ -237,7 +237,7 @@  static void pagealloc_oob_right(struct k
 	ptr = page_address(pages);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
 
-	KUNIT_EXPECT_KASAN_FAIL(test, ptr[size] = 0);
+	KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = ptr[size]);
 	free_pages((unsigned long)ptr, order);
 }
 
@@ -252,7 +252,7 @@  static void pagealloc_uaf(struct kunit *
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
 	free_pages((unsigned long)ptr, order);
 
-	KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = 0);
+	KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[0]);
 }
 
 static void kmalloc_large_oob_right(struct kunit *test)
@@ -514,7 +514,7 @@  static void kmalloc_uaf(struct kunit *te
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
 
 	kfree(ptr);
-	KUNIT_EXPECT_KASAN_FAIL(test, *(ptr + 8) = 'x');
+	KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[8]);
 }
 
 static void kmalloc_uaf_memset(struct kunit *test)
@@ -553,7 +553,7 @@  again:
 		goto again;
 	}
 
-	KUNIT_EXPECT_KASAN_FAIL(test, ptr1[40] = 'x');
+	KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr1)[40]);
 	KUNIT_EXPECT_PTR_NE(test, ptr1, ptr2);
 
 	kfree(ptr2);
@@ -700,7 +700,7 @@  static void ksize_unpoisons_memory(struc
 	ptr[size] = 'x';
 
 	/* This one must. */
-	KUNIT_EXPECT_KASAN_FAIL(test, ptr[real_size] = 'y');
+	KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[real_size]);
 
 	kfree(ptr);
 }