// 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/bitops.h>
#include <linux/delay.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/vmalloc.h>

#include <asm/page.h>

/*
 * Note: test functions are marked noinline so that their names appear in
 * reports.
 */

static noinline void __init kmalloc_oob_right(void)
{
        char *ptr;
        size_t size = 123;

        pr_info("out-of-bounds to right\n");
        ptr = kmalloc(size, GFP_KERNEL);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }

        ptr[size] = 'x';
        kfree(ptr);
}

static noinline void __init kmalloc_oob_left(void)
{
        char *ptr;
        size_t size = 15;

        pr_info("out-of-bounds to left\n");
        ptr = kmalloc(size, GFP_KERNEL);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }

        *ptr = *(ptr - 1);
        kfree(ptr);
}

static noinline void __init kmalloc_node_oob_right(void)
{
        char *ptr;
        size_t size = 4096;

        pr_info("kmalloc_node(): out-of-bounds to right\n");
        ptr = kmalloc_node(size, GFP_KERNEL, 0);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }

        ptr[size] = 0;
        kfree(ptr);
}

#ifdef CONFIG_SLUB
static noinline void __init kmalloc_pagealloc_oob_right(void)
{
        char *ptr;
        size_t size = KMALLOC_MAX_CACHE_SIZE + 10;

        /* Allocate a chunk that does not fit into a SLUB cache to trigger
         * the page allocator fallback.
         */
        pr_info("kmalloc pagealloc allocation: out-of-bounds to right\n");
        ptr = kmalloc(size, GFP_KERNEL);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }

        ptr[size] = 0;
        kfree(ptr);
}

static noinline void __init kmalloc_pagealloc_uaf(void)
{
        char *ptr;
        size_t size = KMALLOC_MAX_CACHE_SIZE + 10;

        pr_info("kmalloc pagealloc allocation: use-after-free\n");
        ptr = kmalloc(size, GFP_KERNEL);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }

        kfree(ptr);
        ptr[0] = 0;
}

static noinline void __init kmalloc_pagealloc_invalid_free(void)
{
        char *ptr;
        size_t size = KMALLOC_MAX_CACHE_SIZE + 10;

        pr_info("kmalloc pagealloc allocation: invalid-free\n");
        ptr = kmalloc(size, GFP_KERNEL);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }

        kfree(ptr + 1);
}
#endif

static noinline void __init kmalloc_large_oob_right(void)
{
        char *ptr;
        size_t size = KMALLOC_MAX_CACHE_SIZE - 256;
        /* Allocate a chunk that is large enough, but still fits into a slab
         * and does not trigger the page allocator fallback in SLUB.
         */
        pr_info("kmalloc large allocation: out-of-bounds to right\n");
        ptr = kmalloc(size, GFP_KERNEL);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }

        ptr[size] = 0;
        kfree(ptr);
}

static noinline void __init kmalloc_oob_krealloc_more(void)
{
        char *ptr1, *ptr2;
        size_t size1 = 17;
        size_t size2 = 19;

        pr_info("out-of-bounds after krealloc more\n");
        ptr1 = kmalloc(size1, GFP_KERNEL);
        ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
        if (!ptr1 || !ptr2) {
                pr_err("Allocation failed\n");
                kfree(ptr1);
                kfree(ptr2);
                return;
        }

        ptr2[size2] = 'x';
        kfree(ptr2);
}

static noinline void __init kmalloc_oob_krealloc_less(void)
{
        char *ptr1, *ptr2;
        size_t size1 = 17;
        size_t size2 = 15;

        pr_info("out-of-bounds after krealloc less\n");
        ptr1 = kmalloc(size1, GFP_KERNEL);
        ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
        if (!ptr1 || !ptr2) {
                pr_err("Allocation failed\n");
                kfree(ptr1);
                return;
        }
        ptr2[size2] = 'x';
        kfree(ptr2);
}

static noinline void __init kmalloc_oob_16(void)
{
        struct {
                u64 words[2];
        } *ptr1, *ptr2;

        pr_info("kmalloc out-of-bounds for 16-bytes access\n");
        ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL);
        ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL);
        if (!ptr1 || !ptr2) {
                pr_err("Allocation failed\n");
                kfree(ptr1);
                kfree(ptr2);
                return;
        }
        *ptr1 = *ptr2;
        kfree(ptr1);
        kfree(ptr2);
}

static noinline void __init kmalloc_oob_memset_2(void)
{
        char *ptr;
        size_t size = 8;

        pr_info("out-of-bounds in memset2\n");
        ptr = kmalloc(size, GFP_KERNEL);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }

        memset(ptr+7, 0, 2);
        kfree(ptr);
}

static noinline void __init kmalloc_oob_memset_4(void)
{
        char *ptr;
        size_t size = 8;

        pr_info("out-of-bounds in memset4\n");
        ptr = kmalloc(size, GFP_KERNEL);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }

        memset(ptr+5, 0, 4);
        kfree(ptr);
}


static noinline void __init kmalloc_oob_memset_8(void)
{
        char *ptr;
        size_t size = 8;

        pr_info("out-of-bounds in memset8\n");
        ptr = kmalloc(size, GFP_KERNEL);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }

        memset(ptr+1, 0, 8);
        kfree(ptr);
}

static noinline void __init kmalloc_oob_memset_16(void)
{
        char *ptr;
        size_t size = 16;

        pr_info("out-of-bounds in memset16\n");
        ptr = kmalloc(size, GFP_KERNEL);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }

        memset(ptr+1, 0, 16);
        kfree(ptr);
}

static noinline void __init kmalloc_oob_in_memset(void)
{
        char *ptr;
        size_t size = 666;

        pr_info("out-of-bounds in memset\n");
        ptr = kmalloc(size, GFP_KERNEL);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }

        memset(ptr, 0, size+5);
        kfree(ptr);
}

static noinline void __init kmalloc_uaf(void)
{
        char *ptr;
        size_t size = 10;

        pr_info("use-after-free\n");
        ptr = kmalloc(size, GFP_KERNEL);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }

        kfree(ptr);
        *(ptr + 8) = 'x';
}

static noinline void __init kmalloc_uaf_memset(void)
{
        char *ptr;
        size_t size = 33;

        pr_info("use-after-free in memset\n");
        ptr = kmalloc(size, GFP_KERNEL);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }

        kfree(ptr);
        memset(ptr, 0, size);
}

static noinline void __init kmalloc_uaf2(void)
{
        char *ptr1, *ptr2;
        size_t size = 43;

        pr_info("use-after-free after another kmalloc\n");
        ptr1 = kmalloc(size, GFP_KERNEL);
        if (!ptr1) {
                pr_err("Allocation failed\n");
                return;
        }

        kfree(ptr1);
        ptr2 = kmalloc(size, GFP_KERNEL);
        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");
        kfree(ptr2);
}

static noinline void __init kfree_via_page(void)
{
        char *ptr;
        size_t size = 8;
        struct page *page;
        unsigned long offset;

        pr_info("invalid-free false positive (via page)\n");
        ptr = kmalloc(size, GFP_KERNEL);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }

        page = virt_to_page(ptr);
        offset = offset_in_page(ptr);
        kfree(page_address(page) + offset);
}

static noinline void __init kfree_via_phys(void)
{
        char *ptr;
        size_t size = 8;
        phys_addr_t phys;

        pr_info("invalid-free false positive (via phys)\n");
        ptr = kmalloc(size, GFP_KERNEL);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }

        phys = virt_to_phys(ptr);
        kfree(phys_to_virt(phys));
}

static noinline void __init kmem_cache_oob(void)
{
        char *p;
        size_t size = 200;
        struct kmem_cache *cache = kmem_cache_create("test_cache",
                                                size, 0,
                                                0, NULL);
        if (!cache) {
                pr_err("Cache allocation failed\n");
                return;
        }
        pr_info("out-of-bounds in kmem_cache_alloc\n");
        p = kmem_cache_alloc(cache, GFP_KERNEL);
        if (!p) {
                pr_err("Allocation failed\n");
                kmem_cache_destroy(cache);
                return;
        }

        *p = p[size];
        kmem_cache_free(cache, p);
        kmem_cache_destroy(cache);
}

static noinline void __init memcg_accounted_kmem_cache(void)
{
        int i;
        char *p;
        size_t size = 200;
        struct kmem_cache *cache;

        cache = kmem_cache_create("test_cache", size, 0, SLAB_ACCOUNT, NULL);
        if (!cache) {
                pr_err("Cache allocation failed\n");
                return;
        }

        pr_info("allocate memcg accounted object\n");
        /*
         * Several allocations with a delay to allow for lazy per memcg kmem
         * cache creation.
         */
        for (i = 0; i < 5; i++) {
                p = kmem_cache_alloc(cache, GFP_KERNEL);
                if (!p)
                        goto free_cache;

                kmem_cache_free(cache, p);
                msleep(100);
        }

free_cache:
        kmem_cache_destroy(cache);
}

static char global_array[10];

static noinline void __init 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 __init 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 __init ksize_unpoisons_memory(void)
{
        char *ptr;
        size_t size = 123, real_size;

        pr_info("ksize() unpoisons the whole allocated chunk\n");
        ptr = kmalloc(size, GFP_KERNEL);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }
        real_size = ksize(ptr);
        /* This access doesn't trigger an error. */
        ptr[size] = 'x';
        /* This one does. */
        ptr[real_size] = 'y';
        kfree(ptr);
}

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);

        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 noinline void __init 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 __init 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 __init kmem_cache_double_free(void)
{
        char *p;
        size_t size = 200;
        struct kmem_cache *cache;

        cache = kmem_cache_create("test_cache", size, 0, 0, NULL);
        if (!cache) {
                pr_err("Cache allocation failed\n");
                return;
        }
        pr_info("double-free on heap object\n");
        p = kmem_cache_alloc(cache, GFP_KERNEL);
        if (!p) {
                pr_err("Allocation failed\n");
                kmem_cache_destroy(cache);
                return;
        }

        kmem_cache_free(cache, p);
        kmem_cache_free(cache, p);
        kmem_cache_destroy(cache);
}

static noinline void __init kmem_cache_invalid_free(void)
{
        char *p;
        size_t size = 200;
        struct kmem_cache *cache;

        cache = kmem_cache_create("test_cache", size, 0, SLAB_TYPESAFE_BY_RCU,
                                  NULL);
        if (!cache) {
                pr_err("Cache allocation failed\n");
                return;
        }
        pr_info("invalid-free of heap object\n");
        p = kmem_cache_alloc(cache, GFP_KERNEL);
        if (!p) {
                pr_err("Allocation failed\n");
                kmem_cache_destroy(cache);
                return;
        }

        /* Trigger invalid free, the object doesn't get freed */
        kmem_cache_free(cache, p + 1);

        /*
         * Properly free the object to prevent the "Objects remaining in
         * test_cache on __kmem_cache_shutdown" BUG failure.
         */
        kmem_cache_free(cache, p);

        kmem_cache_destroy(cache);
}

static noinline void __init kasan_memchr(void)
{
        char *ptr;
        size_t size = 24;

        pr_info("out-of-bounds in memchr\n");
        ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
        if (!ptr)
                return;

        memchr(ptr, '1', size + 1);
        kfree(ptr);
}

static noinline void __init kasan_memcmp(void)
{
        char *ptr;
        size_t size = 24;
        int arr[9];

        pr_info("out-of-bounds in memcmp\n");
        ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
        if (!ptr)
                return;

        memset(arr, 0, sizeof(arr));
        memcmp(ptr, arr, size+1);
        kfree(ptr);
}

static noinline void __init kasan_strings(void)
{
        char *ptr;
        size_t size = 24;

        pr_info("use-after-free in strchr\n");
        ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
        if (!ptr)
                return;

        kfree(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;
        strchr(ptr, '1');

        pr_info("use-after-free in strrchr\n");
        strrchr(ptr, '1');

        pr_info("use-after-free in strcmp\n");
        strcmp(ptr, "2");

        pr_info("use-after-free in strncmp\n");
        strncmp(ptr, "2", 1);

        pr_info("use-after-free in strlen\n");
        strlen(ptr);

        pr_info("use-after-free in strnlen\n");
        strnlen(ptr, 1);
}

static noinline void __init 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 = kzalloc(sizeof(*bits) + 1, GFP_KERNEL);
        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 clear_bit_unlock\n");
        clear_bit_unlock(BITS_PER_LONG, bits);

        pr_info("out-of-bounds in __clear_bit_unlock\n");
        __clear_bit_unlock(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_set_bit_lock\n");
        test_and_set_bit_lock(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");
        (void)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");
        clear_bit_unlock_is_negative_byte(BITS_PER_LONG + BITS_PER_BYTE, bits);
#endif
        kfree(bits);
}

static noinline void __init kmalloc_double_kzfree(void)
{
        char *ptr;
        size_t size = 16;

        pr_info("double-free (kzfree)\n");
        ptr = kmalloc(size, GFP_KERNEL);
        if (!ptr) {
                pr_err("Allocation failed\n");
                return;
        }

        kzfree(ptr);
        kzfree(ptr);
}

#ifdef CONFIG_KASAN_VMALLOC
static noinline void __init vmalloc_oob(void)
{
        void *area;

        pr_info("vmalloc out-of-bounds\n");

        /*
         * We have to be careful not to hit the guard page.
         * The MMU will catch that and crash us.
         */
        area = vmalloc(3000);
        if (!area) {
                pr_err("Allocation failed\n");
                return;
        }

        ((volatile char *)area)[3100];
        vfree(area);
}
#else
static void __init vmalloc_oob(void) {}
#endif

static int __init kmalloc_tests_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();

        kmalloc_oob_right();
        kmalloc_oob_left();
        kmalloc_node_oob_right();
#ifdef CONFIG_SLUB
        kmalloc_pagealloc_oob_right();
        kmalloc_pagealloc_uaf();
        kmalloc_pagealloc_invalid_free();
#endif
        kmalloc_large_oob_right();
        kmalloc_oob_krealloc_more();
        kmalloc_oob_krealloc_less();
        kmalloc_oob_16();
        kmalloc_oob_in_memset();
        kmalloc_oob_memset_2();
        kmalloc_oob_memset_4();
        kmalloc_oob_memset_8();
        kmalloc_oob_memset_16();
        kmalloc_uaf();
        kmalloc_uaf_memset();
        kmalloc_uaf2();
        kfree_via_page();
        kfree_via_phys();
        kmem_cache_oob();
        memcg_accounted_kmem_cache();
        kasan_stack_oob();
        kasan_global_oob();
        kasan_alloca_oob_left();
        kasan_alloca_oob_right();
        ksize_unpoisons_memory();
        copy_user_test();
        kmem_cache_double_free();
        kmem_cache_invalid_free();
        kasan_memchr();
        kasan_memcmp();
        kasan_strings();
        kasan_bitops();
        kmalloc_double_kzfree();
        vmalloc_oob();

        kasan_restore_multi_shot(multishot);

        return -EAGAIN;
}

module_init(kmalloc_tests_init);
MODULE_LICENSE("GPL");