KASAN: port KASAN Tests to KUnit

Transfer all previous tests for KASAN to KUnit so they can be run more
easily.  Using kunit_tool, developers can run these tests with their other
KUnit tests and see "pass" or "fail" with the appropriate KASAN report
instead of needing to parse each KASAN report to test KASAN
functionalities.  All KASAN reports are still printed to dmesg.

Stack tests do not work properly when KASAN_STACK is enabled so those
tests use a check for "if IS_ENABLED(CONFIG_KASAN_STACK)" so they only run
if stack instrumentation is enabled.  If KASAN_STACK is not enabled, KUnit
will print a statement to let the user know this test was not run with
KASAN_STACK enabled.

copy_user_test and kasan_rcu_uaf cannot be run in KUnit so there is a
separate test file for those tests, which can be run as before as a
module.

[trishalfonso@google.com: v14]
  Link: https://lkml.kernel.org/r/20200915035828.570483-4-davidgow@google.com

Signed-off-by: Patricia Alfonso <trishalfonso@google.com>
Signed-off-by: David Gow <davidgow@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20200910070331.3358048-4-davidgow@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 111 insertions, 0 deletions

diff --git a/lib/test_kasan_module.c b/lib/test_kasan_module.c
new file mode 100644
index 000000000000..2d68db6ae67b
--- /dev/null
+++ b/lib/test_kasan_module.c
@@ -0,0 +1,111 @@
+// 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: %s " fmt, __func__
+
+#include <linux/mman.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+#include "../mm/kasan/kasan.h"
+
+#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_SHADOW_SCALE_SIZE)
+
+static noinline void __init copy_user_test(void)
+{
+	char *kmem;
+	char __user *usermem;
+	size_t size = 10;
+	int unused;
+
+	kmem = kmalloc(size, GFP_KERNEL);
+	if (!kmem)
+		return;
+
+	usermem = (char __user *)vm_mmap(NULL, 0, PAGE_SIZE,
+			    PROT_READ | PROT_WRITE | PROT_EXEC,
+			    MAP_ANONYMOUS | MAP_PRIVATE, 0);
+	if (IS_ERR(usermem)) {
+		pr_err("Failed to allocate user memory\n");
+		kfree(kmem);
+		return;
+	}
+
+	pr_info("out-of-bounds in copy_from_user()\n");
+	unused = copy_from_user(kmem, usermem, size + 1 + OOB_TAG_OFF);
+
+	pr_info("out-of-bounds in copy_to_user()\n");
+	unused = copy_to_user(usermem, kmem, size + 1 + OOB_TAG_OFF);
+
+	pr_info("out-of-bounds in __copy_from_user()\n");
+	unused = __copy_from_user(kmem, usermem, size + 1 + OOB_TAG_OFF);
+
+	pr_info("out-of-bounds in __copy_to_user()\n");
+	unused = __copy_to_user(usermem, kmem, size + 1 + OOB_TAG_OFF);
+
+	pr_info("out-of-bounds in __copy_from_user_inatomic()\n");
+	unused = __copy_from_user_inatomic(kmem, usermem, size + 1 + OOB_TAG_OFF);
+
+	pr_info("out-of-bounds in __copy_to_user_inatomic()\n");
+	unused = __copy_to_user_inatomic(usermem, kmem, size + 1 + OOB_TAG_OFF);
+
+	pr_info("out-of-bounds in strncpy_from_user()\n");
+	unused = strncpy_from_user(kmem, usermem, size + 1 + OOB_TAG_OFF);
+
+	vm_munmap((unsigned long)usermem, PAGE_SIZE);
+	kfree(kmem);
+}
+
+static struct kasan_rcu_info {
+	int i;
+	struct rcu_head rcu;
+} *global_rcu_ptr;
+
+static noinline void __init kasan_rcu_reclaim(struct rcu_head *rp)
+{
+	struct kasan_rcu_info *fp = container_of(rp,
+						struct kasan_rcu_info, rcu);
+
+	kfree(fp);
+	fp->i = 1;
+}
+
+static noinline void __init kasan_rcu_uaf(void)
+{
+	struct kasan_rcu_info *ptr;
+
+	pr_info("use-after-free in kasan_rcu_reclaim\n");
+	ptr = kmalloc(sizeof(struct kasan_rcu_info), GFP_KERNEL);
+	if (!ptr) {
+		pr_err("Allocation failed\n");
+		return;
+	}
+
+	global_rcu_ptr = rcu_dereference_protected(ptr, NULL);
+	call_rcu(&global_rcu_ptr->rcu, kasan_rcu_reclaim);
+}
+
+
+static int __init test_kasan_module_init(void)
+{
+	/*
+	 * Temporarily enable multi-shot mode. Otherwise, we'd only get a
+	 * report for the first case.
+	 */
+	bool multishot = kasan_save_enable_multi_shot();
+
+	copy_user_test();
+	kasan_rcu_uaf();
+
+	kasan_restore_multi_shot(multishot);
+	return -EAGAIN;
+}
+
+module_init(test_kasan_module_init);
+MODULE_LICENSE("GPL");