kasan: migrate copy_user_test to kunit

Migrate the copy_user_test to the KUnit framework to verify out-of-bound
detection via KASAN reports in copy_from_user(), copy_to_user() and their
static functions.

This is the last migrated test in kasan_test_module.c, therefore delete
the file.

[arnd@arndb.de: export copy_to_kernel_nofault]
Link: https://lkml.kernel.org/r/20241018151112.3533820-1-arnd@kernel.org
Link: https://lkml.kernel.org/r/20241016131802.3115788-3-snovitoll@gmail.com
Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Marco Elver <elver@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile
index b88543e..1a958e7 100644 (file)
--- a/mm/kasan/Makefile
+++ b/mm/kasan/Makefile
@@ -46,7 +46,6 @@ endif
 
 CFLAGS_kasan_test_c.o := $(CFLAGS_KASAN_TEST)
 RUSTFLAGS_kasan_test_rust.o := $(RUSTFLAGS_KASAN)
-CFLAGS_kasan_test_module.o := $(CFLAGS_KASAN_TEST)
 
 obj-y := common.o report.o
 obj-$(CONFIG_KASAN_GENERIC) += init.o generic.o report_generic.o shadow.o quarantine.o
@@ -59,4 +58,3 @@ ifdef CONFIG_RUST
 endif
 
 obj-$(CONFIG_KASAN_KUNIT_TEST) += kasan_test.o
-obj-$(CONFIG_KASAN_MODULE_TEST) += kasan_test_module.o

diff --git a/mm/kasan/kasan_test_c.c b/mm/kasan/kasan_test_c.c
index fe132ce..fd5058c 100644 (file)
--- a/mm/kasan/kasan_test_c.c
+++ b/mm/kasan/kasan_test_c.c
@@ -1963,6 +1963,52 @@ static void copy_to_kernel_nofault_oob(struct kunit *test)
        kfree(ptr);
 }
 
+static void copy_user_test_oob(struct kunit *test)
+{
+       char *kmem;
+       char __user *usermem;
+       unsigned long useraddr;
+       size_t size = 128 - KASAN_GRANULE_SIZE;
+       int __maybe_unused unused;
+
+       kmem = kunit_kmalloc(test, size, GFP_KERNEL);
+       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, kmem);
+
+       useraddr = kunit_vm_mmap(test, NULL, 0, PAGE_SIZE,
+                                       PROT_READ | PROT_WRITE | PROT_EXEC,
+                                       MAP_ANONYMOUS | MAP_PRIVATE, 0);
+       KUNIT_ASSERT_NE_MSG(test, useraddr, 0,
+               "Could not create userspace mm");
+       KUNIT_ASSERT_LT_MSG(test, useraddr, (unsigned long)TASK_SIZE,
+               "Failed to allocate user memory");
+
+       OPTIMIZER_HIDE_VAR(size);
+       usermem = (char __user *)useraddr;
+
+       KUNIT_EXPECT_KASAN_FAIL(test,
+               unused = copy_from_user(kmem, usermem, size + 1));
+       KUNIT_EXPECT_KASAN_FAIL(test,
+               unused = copy_to_user(usermem, kmem, size + 1));
+       KUNIT_EXPECT_KASAN_FAIL(test,
+               unused = __copy_from_user(kmem, usermem, size + 1));
+       KUNIT_EXPECT_KASAN_FAIL(test,
+               unused = __copy_to_user(usermem, kmem, size + 1));
+       KUNIT_EXPECT_KASAN_FAIL(test,
+               unused = __copy_from_user_inatomic(kmem, usermem, size + 1));
+       KUNIT_EXPECT_KASAN_FAIL(test,
+               unused = __copy_to_user_inatomic(usermem, kmem, size + 1));
+
+       /*
+       * Prepare a long string in usermem to avoid the strncpy_from_user test
+       * bailing out on '\0' before it reaches out-of-bounds.
+       */
+       memset(kmem, 'a', size);
+       KUNIT_EXPECT_EQ(test, copy_to_user(usermem, kmem, size), 0);
+
+       KUNIT_EXPECT_KASAN_FAIL(test,
+               unused = strncpy_from_user(kmem, usermem, size + 1));
+}
+
 static struct kunit_case kasan_kunit_test_cases[] = {
        KUNIT_CASE(kmalloc_oob_right),
        KUNIT_CASE(kmalloc_oob_left),
@@ -2037,6 +2083,7 @@ static struct kunit_case kasan_kunit_test_cases[] = {
        KUNIT_CASE(match_all_mem_tag),
        KUNIT_CASE(copy_to_kernel_nofault_oob),
        KUNIT_CASE(rust_uaf),
+       KUNIT_CASE(copy_user_test_oob),
        {}
 };
 

diff --git a/mm/kasan/kasan_test_module.c b/mm/kasan/kasan_test_module.c
deleted file mode 100644 (file)
index 27ec227..0000000
--- a/mm/kasan/kasan_test_module.c
+++ /dev/null
@@ -1,81 +0,0 @@
-// 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 <linux/mman.h>
-#include <linux/module.h>
-#include <linux/printk.h>
-#include <linux/slab.h>
-#include <linux/uaccess.h>
-
-#include "kasan.h"
-
-static noinline void __init copy_user_test(void)
-{
-       char *kmem;
-       char __user *usermem;
-       size_t size = 128 - KASAN_GRANULE_SIZE;
-       int __maybe_unused 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;
-       }
-
-       OPTIMIZER_HIDE_VAR(size);
-
-       pr_info("out-of-bounds in copy_from_user()\n");
-       unused = copy_from_user(kmem, usermem, size + 1);
-
-       pr_info("out-of-bounds in copy_to_user()\n");
-       unused = copy_to_user(usermem, kmem, size + 1);
-
-       pr_info("out-of-bounds in __copy_from_user()\n");
-       unused = __copy_from_user(kmem, usermem, size + 1);
-
-       pr_info("out-of-bounds in __copy_to_user()\n");
-       unused = __copy_to_user(usermem, kmem, size + 1);
-
-       pr_info("out-of-bounds in __copy_from_user_inatomic()\n");
-       unused = __copy_from_user_inatomic(kmem, usermem, size + 1);
-
-       pr_info("out-of-bounds in __copy_to_user_inatomic()\n");
-       unused = __copy_to_user_inatomic(usermem, kmem, size + 1);
-
-       pr_info("out-of-bounds in strncpy_from_user()\n");
-       unused = strncpy_from_user(kmem, usermem, size + 1);
-
-       vm_munmap((unsigned long)usermem, PAGE_SIZE);
-       kfree(kmem);
-}
-
-static int __init kasan_test_module_init(void)
-{
-       /*
-        * Temporarily enable multi-shot mode. Otherwise, KASAN would only
-        * report the first detected bug and panic the kernel if panic_on_warn
-        * is enabled.
-        */
-       bool multishot = kasan_save_enable_multi_shot();
-
-       copy_user_test();
-
-       kasan_restore_multi_shot(multishot);
-       return -EAGAIN;
-}
-
-module_init(kasan_test_module_init);
-MODULE_LICENSE("GPL");

diff --git a/mm/maccess.c b/mm/maccess.c
index 3ca55ec..8f09061 100644 (file)
--- a/mm/maccess.c
+++ b/mm/maccess.c
@@ -82,6 +82,7 @@ Efault:
        pagefault_enable();
        return -EFAULT;
 }
+EXPORT_SYMBOL_GPL(copy_to_kernel_nofault);
 
 long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count)
 {