Re: [PATCH 1/2] lib: kasan: remove reference of non-existent test_kasan.o

[Sascha Hauer <s.hauer@pengutronix.de>]

On Mon, Sep 28, 2020 at 04:41:45PM +0200, Ahmad Fatoum wrote:
> We don't have anything that test_kasan.o can be generated out of,
> thus drop it to fix the build.
> 
> It would still be nice to have this as a command, but that
> should be a separate patch.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  lib/kasan/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

I prefer to add the code that I have forgotten to git add ;)

Sascha

----------------------8<-----------------


From ff5cbfcbbe21d7883e3ce661fec3751f7cb7e58c Mon Sep 17 00:00:00 2001
From: Sascha Hauer <s.hauer@pengutronix.de>
Date: Mon, 28 Sep 2020 16:56:36 +0200
Subject: [PATCH] KASan: Add missing test code

Add missing test code.

Fixes: 6cd9d2d600 ("Add KASan support")
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 lib/kasan/test_kasan.c | 478 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 478 insertions(+)
 create mode 100644 lib/kasan/test_kasan.c

diff --git a/lib/kasan/test_kasan.c b/lib/kasan/test_kasan.c
new file mode 100644
index 0000000000..e472bb3499
--- /dev/null
+++ b/lib/kasan/test_kasan.c
@@ -0,0 +1,478 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ * Author: Andrey Ryabinin <a.ryabinin@samsung.com>
+ */
+
+#define pr_fmt(fmt) "kasan test: " fmt
+
+#include <common.h>
+#include <command.h>
+#include <complete.h>
+
+#include "kasan.h"
+
+/*
+ * We assign some test results to these globals to make sure the tests
+ * are not eliminated as dead code.
+ */
+
+int kasan_int_result;
+void *kasan_ptr_result;
+
+/*
+ * Note: test functions are marked noinline so that their names appear in
+ * reports.
+ */
+
+static noinline void malloc_oob_right(void)
+{
+	char *ptr;
+	size_t size = 123;
+
+	pr_info("out-of-bounds to right\n");
+	ptr = malloc(size);
+	if (!ptr) {
+		pr_err("Allocation failed\n");
+		return;
+	}
+
+	ptr[size] = 'x';
+
+	free(ptr);
+}
+
+static noinline void malloc_oob_left(void)
+{
+	char *ptr;
+	size_t size = 15;
+
+	pr_info("out-of-bounds to left\n");
+	ptr = malloc(size);
+	if (!ptr) {
+		pr_err("Allocation failed\n");
+		return;
+	}
+
+	*ptr = *(ptr - 1);
+	free(ptr);
+}
+
+static noinline void malloc_oob_realloc_more(void)
+{
+	char *ptr1, *ptr2;
+	size_t size1 = 17;
+	size_t size2 = 19;
+
+	pr_info("out-of-bounds after krealloc more\n");
+	ptr1 = malloc(size1);
+	ptr2 = realloc(ptr1, size2);
+	if (!ptr1 || !ptr2) {
+		pr_err("Allocation failed\n");
+		free(ptr1);
+		free(ptr2);
+		return;
+	}
+
+	ptr2[size2] = 'x';
+
+	free(ptr2);
+}
+
+static noinline void malloc_oob_realloc_less(void)
+{
+	char *ptr1, *ptr2;
+	size_t size1 = 17;
+	size_t size2 = 15;
+
+	pr_info("out-of-bounds after krealloc less\n");
+	ptr1 = malloc(size1);
+	ptr2 = realloc(ptr1, size2);
+	if (!ptr1 || !ptr2) {
+		pr_err("Allocation failed\n");
+		free(ptr1);
+		return;
+	}
+
+	ptr2[size2] = 'x';
+
+	free(ptr2);
+}
+
+static noinline void malloc_oob_16(void)
+{
+	struct {
+		u64 words[2];
+	} *ptr1, *ptr2;
+
+	pr_info("malloc out-of-bounds for 16-bytes access\n");
+	ptr1 = malloc(sizeof(*ptr1) - 3);
+	ptr2 = malloc(sizeof(*ptr2));
+	if (!ptr1 || !ptr2) {
+		pr_err("Allocation failed\n");
+		free(ptr1);
+		free(ptr2);
+		return;
+	}
+	*ptr1 = *ptr2;
+	free(ptr1);
+	free(ptr2);
+}
+
+static noinline void malloc_oob_memset_2(void)
+{
+	char *ptr;
+	size_t size = 8;
+
+	pr_info("out-of-bounds in memset2\n");
+	ptr = malloc(size);
+	if (!ptr) {
+		pr_err("Allocation failed\n");
+		return;
+	}
+
+	memset(ptr + 7, 0, 2);
+
+	free(ptr);
+}
+
+static noinline void malloc_oob_memset_4(void)
+{
+	char *ptr;
+	size_t size = 8;
+
+	pr_info("out-of-bounds in memset4\n");
+	ptr = malloc(size);
+	if (!ptr) {
+		pr_err("Allocation failed\n");
+		return;
+	}
+
+	memset(ptr + 5, 0, 4);
+
+	free(ptr);
+}
+
+
+static noinline void malloc_oob_memset_8(void)
+{
+	char *ptr;
+	size_t size = 8;
+
+	pr_info("out-of-bounds in memset8\n");
+	ptr = malloc(size);
+	if (!ptr) {
+		pr_err("Allocation failed\n");
+		return;
+	}
+
+	memset(ptr + 1, 0, 8);
+
+	free(ptr);
+}
+
+static noinline void malloc_oob_memset_16(void)
+{
+	char *ptr;
+	size_t size = 16;
+
+	pr_info("out-of-bounds in memset16\n");
+	ptr = malloc(size);
+	if (!ptr) {
+		pr_err("Allocation failed\n");
+		return;
+	}
+
+	memset(ptr + 1, 0, 16);
+
+	free(ptr);
+}
+
+static noinline void malloc_oob_in_memset(void)
+{
+	char *ptr;
+	size_t size = 666;
+
+	pr_info("out-of-bounds in memset\n");
+	ptr = malloc(size);
+	if (!ptr) {
+		pr_err("Allocation failed\n");
+		return;
+	}
+
+	memset(ptr, 0, size + 5);
+
+	free(ptr);
+}
+
+static noinline void malloc_uaf(void)
+{
+	char *ptr;
+	size_t size = 10;
+
+	pr_info("use-after-free\n");
+	ptr = malloc(size);
+	if (!ptr) {
+		pr_err("Allocation failed\n");
+		return;
+	}
+
+	free(ptr);
+	*(ptr + 8) = 'x';
+}
+
+static noinline void malloc_uaf_memset(void)
+{
+	char *ptr;
+	size_t size = 33;
+
+	pr_info("use-after-free in memset\n");
+	ptr = malloc(size);
+	if (!ptr) {
+		pr_err("Allocation failed\n");
+		return;
+	}
+
+	free(ptr);
+	memset(ptr, 0, size);
+}
+
+static noinline void malloc_uaf2(void)
+{
+	char *ptr1, *ptr2;
+	size_t size = 43;
+
+	pr_info("use-after-free after another malloc\n");
+	ptr1 = malloc(size);
+	if (!ptr1) {
+		pr_err("Allocation failed\n");
+		return;
+	}
+
+	free(ptr1);
+	ptr2 = malloc(size);
+	if (!ptr2) {
+		pr_err("Allocation failed\n");
+		return;
+	}
+
+	ptr1[40] = 'x';
+	if (ptr1 == ptr2)
+		pr_err("Could not detect use-after-free: ptr1 == ptr2\n");
+	free(ptr2);
+}
+
+static char global_array[10];
+
+static noinline void kasan_global_oob(void)
+{
+	volatile int i = 3;
+	char *p = &global_array[ARRAY_SIZE(global_array) + i];
+
+	pr_info("out-of-bounds global variable\n");
+	*(volatile char *)p;
+}
+
+static noinline void kasan_stack_oob(void)
+{
+	char stack_array[10];
+	volatile int i = 0;
+	char *p = &stack_array[ARRAY_SIZE(stack_array) + i];
+
+	pr_info("out-of-bounds on stack\n");
+	*(volatile char *)p;
+}
+
+static noinline void kasan_alloca_oob_left(void)
+{
+	volatile int i = 10;
+	char alloca_array[i];
+	char *p = alloca_array - 1;
+
+	pr_info("out-of-bounds to left on alloca\n");
+	*(volatile char *)p;
+}
+
+static noinline void kasan_alloca_oob_right(void)
+{
+	volatile int i = 10;
+	char alloca_array[i];
+	char *p = alloca_array + i;
+
+	pr_info("out-of-bounds to right on alloca\n");
+	*(volatile char *)p;
+}
+
+static noinline void kasan_memchr(void)
+{
+	char *ptr;
+	size_t size = 24;
+
+	pr_info("out-of-bounds in memchr\n");
+	ptr = kzalloc(size, 0);
+	if (!ptr)
+		return;
+
+	kasan_ptr_result = memchr(ptr, '1', size + 1);
+	free(ptr);
+}
+
+static noinline void kasan_memcmp(void)
+{
+	char *ptr;
+	size_t size = 24;
+	int arr[9];
+
+	pr_info("out-of-bounds in memcmp\n");
+	ptr = kzalloc(size, 0);
+	if (!ptr)
+		return;
+
+	memset(arr, 0, sizeof(arr));
+	kasan_int_result = memcmp(ptr, arr, size + 1);
+	free(ptr);
+}
+
+static noinline void kasan_strings(void)
+{
+	char *ptr;
+	size_t size = 24;
+
+	pr_info("use-after-free in strchr\n");
+	ptr = malloc(size);
+	if (!ptr)
+		return;
+
+	free(ptr);
+
+	/*
+	 * Try to cause only 1 invalid access (less spam in dmesg).
+	 * For that we need ptr to point to zeroed byte.
+	 * Skip metadata that could be stored in freed object so ptr
+	 * will likely point to zeroed byte.
+	 */
+	ptr += 16;
+	kasan_ptr_result = strchr(ptr, '1');
+
+	pr_info("use-after-free in strrchr\n");
+	kasan_ptr_result = strrchr(ptr, '1');
+
+	pr_info("use-after-free in strcmp\n");
+	kasan_int_result = strcmp(ptr, "2");
+
+	pr_info("use-after-free in strncmp\n");
+	kasan_int_result = strncmp(ptr, "2", 1);
+
+	pr_info("use-after-free in strlen\n");
+	kasan_int_result = strlen(ptr);
+
+	pr_info("use-after-free in strnlen\n");
+	kasan_int_result = strnlen(ptr, 1);
+}
+
+static noinline void kasan_bitops(void)
+{
+	/*
+	 * Allocate 1 more byte, which causes kzalloc to round up to 16-bytes;
+	 * this way we do not actually corrupt other memory.
+	 */
+	long *bits = xzalloc(sizeof(*bits) + 1);
+	if (!bits)
+		return;
+
+	/*
+	 * Below calls try to access bit within allocated memory; however, the
+	 * below accesses are still out-of-bounds, since bitops are defined to
+	 * operate on the whole long the bit is in.
+	 */
+	pr_info("out-of-bounds in set_bit\n");
+	set_bit(BITS_PER_LONG, bits);
+
+	pr_info("out-of-bounds in __set_bit\n");
+	__set_bit(BITS_PER_LONG, bits);
+
+	pr_info("out-of-bounds in clear_bit\n");
+	clear_bit(BITS_PER_LONG, bits);
+
+	pr_info("out-of-bounds in __clear_bit\n");
+	__clear_bit(BITS_PER_LONG, bits);
+
+	pr_info("out-of-bounds in change_bit\n");
+	change_bit(BITS_PER_LONG, bits);
+
+	pr_info("out-of-bounds in __change_bit\n");
+	__change_bit(BITS_PER_LONG, bits);
+
+	/*
+	 * Below calls try to access bit beyond allocated memory.
+	 */
+	pr_info("out-of-bounds in test_and_set_bit\n");
+	test_and_set_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
+
+	pr_info("out-of-bounds in __test_and_set_bit\n");
+	__test_and_set_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
+
+	pr_info("out-of-bounds in test_and_clear_bit\n");
+	test_and_clear_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
+
+	pr_info("out-of-bounds in __test_and_clear_bit\n");
+	__test_and_clear_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
+
+	pr_info("out-of-bounds in test_and_change_bit\n");
+	test_and_change_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
+
+	pr_info("out-of-bounds in __test_and_change_bit\n");
+	__test_and_change_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
+
+	pr_info("out-of-bounds in test_bit\n");
+	kasan_int_result = test_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
+
+#if defined(clear_bit_unlock_is_negative_byte)
+	pr_info("out-of-bounds in clear_bit_unlock_is_negative_byte\n");
+	kasan_int_result = clear_bit_unlock_is_negative_byte(BITS_PER_LONG +
+		BITS_PER_BYTE, bits);
+#endif
+	free(bits);
+}
+
+static int do_kasan_test(int argc, char *argv[])
+{
+	/*
+	 * Temporarily enable multi-shot mode. Otherwise, we'd only get a
+	 * report for the first case.
+	 */
+	bool multishot = kasan_save_enable_multi_shot();
+
+	malloc_oob_right();
+	malloc_oob_left();
+	malloc_oob_realloc_more();
+	malloc_oob_realloc_less();
+	malloc_oob_16();
+	malloc_oob_in_memset();
+	malloc_oob_memset_2();
+	malloc_oob_memset_4();
+	malloc_oob_memset_8();
+	malloc_oob_memset_16();
+	malloc_uaf();
+	malloc_uaf_memset();
+	malloc_uaf2();
+	kasan_stack_oob();
+	kasan_global_oob();
+	kasan_alloca_oob_left();
+	kasan_alloca_oob_right();
+	kasan_memchr();
+	kasan_memcmp();
+	kasan_strings();
+	kasan_bitops();
+
+	kasan_restore_multi_shot(multishot);
+
+        return 0;
+}
+
+BAREBOX_CMD_START(kasan_tests)
+        .cmd            = do_kasan_test,
+        BAREBOX_CMD_DESC("Run KAsan tests")
+        BAREBOX_CMD_COMPLETE(empty_complete)
+BAREBOX_CMD_END
-- 
2.28.0

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