![Alexander Potapenko](/assets/img/avatar_default.png)
This patchset implements SLAB support for KASAN Unlike SLUB, SLAB doesn't store allocation/deallocation stacks for heap objects, therefore we reimplement this feature in mm/kasan/stackdepot.c. The intention is to ultimately switch SLUB to use this implementation as well, which will save a lot of memory (right now SLUB bloats each object by 256 bytes to store the allocation/deallocation stacks). Also neither SLUB nor SLAB delay the reuse of freed memory chunks, which is necessary for better detection of use-after-free errors. We introduce memory quarantine (mm/kasan/quarantine.c), which allows delayed reuse of deallocated memory. This patch (of 7): Rename kmalloc_large_oob_right() to kmalloc_pagealloc_oob_right(), as the test only checks the page allocator functionality. Also reimplement kmalloc_large_oob_right() so that the test allocates a large enough chunk of memory that still does not trigger the page allocator fallback. Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andrey Konovalov <adech.fo@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
373 lines
6.9 KiB
C
373 lines
6.9 KiB
C
/*
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*
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* Copyright (c) 2014 Samsung Electronics Co., Ltd.
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* Author: Andrey Ryabinin <a.ryabinin@samsung.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#define pr_fmt(fmt) "kasan test: %s " fmt, __func__
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#include <linux/kernel.h>
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#include <linux/printk.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/module.h>
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static noinline void __init kmalloc_oob_right(void)
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{
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char *ptr;
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size_t size = 123;
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pr_info("out-of-bounds to right\n");
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ptr = kmalloc(size, GFP_KERNEL);
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if (!ptr) {
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pr_err("Allocation failed\n");
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return;
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}
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ptr[size] = 'x';
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kfree(ptr);
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}
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static noinline void __init kmalloc_oob_left(void)
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{
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char *ptr;
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size_t size = 15;
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pr_info("out-of-bounds to left\n");
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ptr = kmalloc(size, GFP_KERNEL);
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if (!ptr) {
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pr_err("Allocation failed\n");
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return;
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}
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*ptr = *(ptr - 1);
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kfree(ptr);
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}
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static noinline void __init kmalloc_node_oob_right(void)
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{
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char *ptr;
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size_t size = 4096;
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pr_info("kmalloc_node(): out-of-bounds to right\n");
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ptr = kmalloc_node(size, GFP_KERNEL, 0);
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if (!ptr) {
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pr_err("Allocation failed\n");
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return;
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}
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ptr[size] = 0;
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kfree(ptr);
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}
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#ifdef CONFIG_SLUB
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static noinline void __init kmalloc_pagealloc_oob_right(void)
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{
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char *ptr;
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size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
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/* Allocate a chunk that does not fit into a SLUB cache to trigger
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* the page allocator fallback.
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*/
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pr_info("kmalloc pagealloc allocation: out-of-bounds to right\n");
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ptr = kmalloc(size, GFP_KERNEL);
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if (!ptr) {
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pr_err("Allocation failed\n");
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return;
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}
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ptr[size] = 0;
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kfree(ptr);
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}
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#endif
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static noinline void __init kmalloc_large_oob_right(void)
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{
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char *ptr;
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size_t size = KMALLOC_MAX_CACHE_SIZE - 256;
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/* Allocate a chunk that is large enough, but still fits into a slab
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* and does not trigger the page allocator fallback in SLUB.
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*/
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pr_info("kmalloc large allocation: out-of-bounds to right\n");
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ptr = kmalloc(size, GFP_KERNEL);
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if (!ptr) {
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pr_err("Allocation failed\n");
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return;
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}
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ptr[size] = 0;
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kfree(ptr);
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}
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static noinline void __init kmalloc_oob_krealloc_more(void)
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{
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char *ptr1, *ptr2;
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size_t size1 = 17;
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size_t size2 = 19;
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pr_info("out-of-bounds after krealloc more\n");
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ptr1 = kmalloc(size1, GFP_KERNEL);
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ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
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if (!ptr1 || !ptr2) {
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pr_err("Allocation failed\n");
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kfree(ptr1);
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return;
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}
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ptr2[size2] = 'x';
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kfree(ptr2);
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}
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static noinline void __init kmalloc_oob_krealloc_less(void)
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{
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char *ptr1, *ptr2;
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size_t size1 = 17;
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size_t size2 = 15;
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pr_info("out-of-bounds after krealloc less\n");
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ptr1 = kmalloc(size1, GFP_KERNEL);
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ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
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if (!ptr1 || !ptr2) {
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pr_err("Allocation failed\n");
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kfree(ptr1);
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return;
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}
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ptr2[size2] = 'x';
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kfree(ptr2);
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}
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static noinline void __init kmalloc_oob_16(void)
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{
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struct {
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u64 words[2];
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} *ptr1, *ptr2;
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pr_info("kmalloc out-of-bounds for 16-bytes access\n");
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ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL);
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ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL);
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if (!ptr1 || !ptr2) {
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pr_err("Allocation failed\n");
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kfree(ptr1);
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kfree(ptr2);
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return;
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}
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*ptr1 = *ptr2;
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kfree(ptr1);
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kfree(ptr2);
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}
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static noinline void __init kmalloc_oob_memset_2(void)
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{
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char *ptr;
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size_t size = 8;
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pr_info("out-of-bounds in memset2\n");
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ptr = kmalloc(size, GFP_KERNEL);
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if (!ptr) {
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pr_err("Allocation failed\n");
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return;
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}
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memset(ptr+7, 0, 2);
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kfree(ptr);
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}
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static noinline void __init kmalloc_oob_memset_4(void)
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{
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char *ptr;
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size_t size = 8;
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pr_info("out-of-bounds in memset4\n");
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ptr = kmalloc(size, GFP_KERNEL);
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if (!ptr) {
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pr_err("Allocation failed\n");
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return;
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}
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memset(ptr+5, 0, 4);
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kfree(ptr);
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}
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static noinline void __init kmalloc_oob_memset_8(void)
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{
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char *ptr;
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size_t size = 8;
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pr_info("out-of-bounds in memset8\n");
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ptr = kmalloc(size, GFP_KERNEL);
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if (!ptr) {
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pr_err("Allocation failed\n");
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return;
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}
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memset(ptr+1, 0, 8);
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kfree(ptr);
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}
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static noinline void __init kmalloc_oob_memset_16(void)
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{
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char *ptr;
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size_t size = 16;
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pr_info("out-of-bounds in memset16\n");
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ptr = kmalloc(size, GFP_KERNEL);
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if (!ptr) {
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pr_err("Allocation failed\n");
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return;
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}
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memset(ptr+1, 0, 16);
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kfree(ptr);
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}
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static noinline void __init kmalloc_oob_in_memset(void)
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{
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char *ptr;
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size_t size = 666;
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pr_info("out-of-bounds in memset\n");
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ptr = kmalloc(size, GFP_KERNEL);
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if (!ptr) {
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pr_err("Allocation failed\n");
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return;
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}
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memset(ptr, 0, size+5);
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kfree(ptr);
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}
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static noinline void __init kmalloc_uaf(void)
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{
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char *ptr;
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size_t size = 10;
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pr_info("use-after-free\n");
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ptr = kmalloc(size, GFP_KERNEL);
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if (!ptr) {
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pr_err("Allocation failed\n");
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return;
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}
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kfree(ptr);
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*(ptr + 8) = 'x';
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}
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static noinline void __init kmalloc_uaf_memset(void)
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{
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char *ptr;
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size_t size = 33;
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pr_info("use-after-free in memset\n");
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ptr = kmalloc(size, GFP_KERNEL);
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if (!ptr) {
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pr_err("Allocation failed\n");
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return;
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}
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kfree(ptr);
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memset(ptr, 0, size);
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}
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static noinline void __init kmalloc_uaf2(void)
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{
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char *ptr1, *ptr2;
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size_t size = 43;
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pr_info("use-after-free after another kmalloc\n");
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ptr1 = kmalloc(size, GFP_KERNEL);
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if (!ptr1) {
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pr_err("Allocation failed\n");
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return;
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}
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kfree(ptr1);
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ptr2 = kmalloc(size, GFP_KERNEL);
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if (!ptr2) {
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pr_err("Allocation failed\n");
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return;
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}
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ptr1[40] = 'x';
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kfree(ptr2);
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}
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static noinline void __init kmem_cache_oob(void)
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{
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char *p;
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size_t size = 200;
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struct kmem_cache *cache = kmem_cache_create("test_cache",
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size, 0,
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0, NULL);
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if (!cache) {
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pr_err("Cache allocation failed\n");
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return;
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}
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pr_info("out-of-bounds in kmem_cache_alloc\n");
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p = kmem_cache_alloc(cache, GFP_KERNEL);
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if (!p) {
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pr_err("Allocation failed\n");
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kmem_cache_destroy(cache);
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return;
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}
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*p = p[size];
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kmem_cache_free(cache, p);
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kmem_cache_destroy(cache);
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}
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static char global_array[10];
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static noinline void __init kasan_global_oob(void)
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{
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volatile int i = 3;
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char *p = &global_array[ARRAY_SIZE(global_array) + i];
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pr_info("out-of-bounds global variable\n");
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*(volatile char *)p;
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}
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static noinline void __init kasan_stack_oob(void)
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{
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char stack_array[10];
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volatile int i = 0;
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char *p = &stack_array[ARRAY_SIZE(stack_array) + i];
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pr_info("out-of-bounds on stack\n");
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*(volatile char *)p;
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}
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static int __init kmalloc_tests_init(void)
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{
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kmalloc_oob_right();
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kmalloc_oob_left();
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kmalloc_node_oob_right();
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#ifdef CONFIG_SLUB
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kmalloc_pagealloc_oob_right();
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#endif
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kmalloc_large_oob_right();
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kmalloc_oob_krealloc_more();
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kmalloc_oob_krealloc_less();
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kmalloc_oob_16();
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kmalloc_oob_in_memset();
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kmalloc_oob_memset_2();
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kmalloc_oob_memset_4();
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kmalloc_oob_memset_8();
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kmalloc_oob_memset_16();
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kmalloc_uaf();
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kmalloc_uaf_memset();
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kmalloc_uaf2();
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kmem_cache_oob();
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kasan_stack_oob();
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kasan_global_oob();
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return -EAGAIN;
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}
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module_init(kmalloc_tests_init);
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MODULE_LICENSE("GPL");
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