316 lines
7.2 KiB
C
316 lines
7.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* This is for all the tests relating directly to heap memory, including
|
|
* page allocation and slab allocations.
|
|
*/
|
|
#include "lkdtm.h"
|
|
#include <linux/slab.h>
|
|
#include <linux/vmalloc.h>
|
|
#include <linux/sched.h>
|
|
|
|
static struct kmem_cache *double_free_cache;
|
|
static struct kmem_cache *a_cache;
|
|
static struct kmem_cache *b_cache;
|
|
|
|
/*
|
|
* Using volatile here means the compiler cannot ever make assumptions
|
|
* about this value. This means compile-time length checks involving
|
|
* this variable cannot be performed; only run-time checks.
|
|
*/
|
|
static volatile int __offset = 1;
|
|
|
|
/*
|
|
* If there aren't guard pages, it's likely that a consecutive allocation will
|
|
* let us overflow into the second allocation without overwriting something real.
|
|
*/
|
|
void lkdtm_VMALLOC_LINEAR_OVERFLOW(void)
|
|
{
|
|
char *one, *two;
|
|
|
|
one = vzalloc(PAGE_SIZE);
|
|
two = vzalloc(PAGE_SIZE);
|
|
|
|
pr_info("Attempting vmalloc linear overflow ...\n");
|
|
memset(one, 0xAA, PAGE_SIZE + __offset);
|
|
|
|
vfree(two);
|
|
vfree(one);
|
|
}
|
|
|
|
/*
|
|
* This tries to stay within the next largest power-of-2 kmalloc cache
|
|
* to avoid actually overwriting anything important if it's not detected
|
|
* correctly.
|
|
*/
|
|
void lkdtm_SLAB_LINEAR_OVERFLOW(void)
|
|
{
|
|
size_t len = 1020;
|
|
u32 *data = kmalloc(len, GFP_KERNEL);
|
|
if (!data)
|
|
return;
|
|
|
|
pr_info("Attempting slab linear overflow ...\n");
|
|
data[1024 / sizeof(u32)] = 0x12345678;
|
|
kfree(data);
|
|
}
|
|
|
|
void lkdtm_WRITE_AFTER_FREE(void)
|
|
{
|
|
int *base, *again;
|
|
size_t len = 1024;
|
|
/*
|
|
* The slub allocator uses the first word to store the free
|
|
* pointer in some configurations. Use the middle of the
|
|
* allocation to avoid running into the freelist
|
|
*/
|
|
size_t offset = (len / sizeof(*base)) / 2;
|
|
|
|
base = kmalloc(len, GFP_KERNEL);
|
|
if (!base)
|
|
return;
|
|
pr_info("Allocated memory %p-%p\n", base, &base[offset * 2]);
|
|
pr_info("Attempting bad write to freed memory at %p\n",
|
|
&base[offset]);
|
|
kfree(base);
|
|
base[offset] = 0x0abcdef0;
|
|
/* Attempt to notice the overwrite. */
|
|
again = kmalloc(len, GFP_KERNEL);
|
|
kfree(again);
|
|
if (again != base)
|
|
pr_info("Hmm, didn't get the same memory range.\n");
|
|
}
|
|
|
|
void lkdtm_READ_AFTER_FREE(void)
|
|
{
|
|
int *base, *val, saw;
|
|
size_t len = 1024;
|
|
/*
|
|
* The slub allocator will use the either the first word or
|
|
* the middle of the allocation to store the free pointer,
|
|
* depending on configurations. Store in the second word to
|
|
* avoid running into the freelist.
|
|
*/
|
|
size_t offset = sizeof(*base);
|
|
|
|
base = kmalloc(len, GFP_KERNEL);
|
|
if (!base) {
|
|
pr_info("Unable to allocate base memory.\n");
|
|
return;
|
|
}
|
|
|
|
val = kmalloc(len, GFP_KERNEL);
|
|
if (!val) {
|
|
pr_info("Unable to allocate val memory.\n");
|
|
kfree(base);
|
|
return;
|
|
}
|
|
|
|
*val = 0x12345678;
|
|
base[offset] = *val;
|
|
pr_info("Value in memory before free: %x\n", base[offset]);
|
|
|
|
kfree(base);
|
|
|
|
pr_info("Attempting bad read from freed memory\n");
|
|
saw = base[offset];
|
|
if (saw != *val) {
|
|
/* Good! Poisoning happened, so declare a win. */
|
|
pr_info("Memory correctly poisoned (%x)\n", saw);
|
|
} else {
|
|
pr_err("FAIL: Memory was not poisoned!\n");
|
|
pr_expected_config_param(CONFIG_INIT_ON_FREE_DEFAULT_ON, "init_on_free");
|
|
}
|
|
|
|
kfree(val);
|
|
}
|
|
|
|
void lkdtm_WRITE_BUDDY_AFTER_FREE(void)
|
|
{
|
|
unsigned long p = __get_free_page(GFP_KERNEL);
|
|
if (!p) {
|
|
pr_info("Unable to allocate free page\n");
|
|
return;
|
|
}
|
|
|
|
pr_info("Writing to the buddy page before free\n");
|
|
memset((void *)p, 0x3, PAGE_SIZE);
|
|
free_page(p);
|
|
schedule();
|
|
pr_info("Attempting bad write to the buddy page after free\n");
|
|
memset((void *)p, 0x78, PAGE_SIZE);
|
|
/* Attempt to notice the overwrite. */
|
|
p = __get_free_page(GFP_KERNEL);
|
|
free_page(p);
|
|
schedule();
|
|
}
|
|
|
|
void lkdtm_READ_BUDDY_AFTER_FREE(void)
|
|
{
|
|
unsigned long p = __get_free_page(GFP_KERNEL);
|
|
int saw, *val;
|
|
int *base;
|
|
|
|
if (!p) {
|
|
pr_info("Unable to allocate free page\n");
|
|
return;
|
|
}
|
|
|
|
val = kmalloc(1024, GFP_KERNEL);
|
|
if (!val) {
|
|
pr_info("Unable to allocate val memory.\n");
|
|
free_page(p);
|
|
return;
|
|
}
|
|
|
|
base = (int *)p;
|
|
|
|
*val = 0x12345678;
|
|
base[0] = *val;
|
|
pr_info("Value in memory before free: %x\n", base[0]);
|
|
free_page(p);
|
|
pr_info("Attempting to read from freed memory\n");
|
|
saw = base[0];
|
|
if (saw != *val) {
|
|
/* Good! Poisoning happened, so declare a win. */
|
|
pr_info("Memory correctly poisoned (%x)\n", saw);
|
|
} else {
|
|
pr_err("FAIL: Buddy page was not poisoned!\n");
|
|
pr_expected_config_param(CONFIG_INIT_ON_FREE_DEFAULT_ON, "init_on_free");
|
|
}
|
|
|
|
kfree(val);
|
|
}
|
|
|
|
void lkdtm_SLAB_INIT_ON_ALLOC(void)
|
|
{
|
|
u8 *first;
|
|
u8 *val;
|
|
|
|
first = kmalloc(512, GFP_KERNEL);
|
|
if (!first) {
|
|
pr_info("Unable to allocate 512 bytes the first time.\n");
|
|
return;
|
|
}
|
|
|
|
memset(first, 0xAB, 512);
|
|
kfree(first);
|
|
|
|
val = kmalloc(512, GFP_KERNEL);
|
|
if (!val) {
|
|
pr_info("Unable to allocate 512 bytes the second time.\n");
|
|
return;
|
|
}
|
|
if (val != first) {
|
|
pr_warn("Reallocation missed clobbered memory.\n");
|
|
}
|
|
|
|
if (memchr(val, 0xAB, 512) == NULL) {
|
|
pr_info("Memory appears initialized (%x, no earlier values)\n", *val);
|
|
} else {
|
|
pr_err("FAIL: Slab was not initialized\n");
|
|
pr_expected_config_param(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, "init_on_alloc");
|
|
}
|
|
kfree(val);
|
|
}
|
|
|
|
void lkdtm_BUDDY_INIT_ON_ALLOC(void)
|
|
{
|
|
u8 *first;
|
|
u8 *val;
|
|
|
|
first = (u8 *)__get_free_page(GFP_KERNEL);
|
|
if (!first) {
|
|
pr_info("Unable to allocate first free page\n");
|
|
return;
|
|
}
|
|
|
|
memset(first, 0xAB, PAGE_SIZE);
|
|
free_page((unsigned long)first);
|
|
|
|
val = (u8 *)__get_free_page(GFP_KERNEL);
|
|
if (!val) {
|
|
pr_info("Unable to allocate second free page\n");
|
|
return;
|
|
}
|
|
|
|
if (val != first) {
|
|
pr_warn("Reallocation missed clobbered memory.\n");
|
|
}
|
|
|
|
if (memchr(val, 0xAB, PAGE_SIZE) == NULL) {
|
|
pr_info("Memory appears initialized (%x, no earlier values)\n", *val);
|
|
} else {
|
|
pr_err("FAIL: Slab was not initialized\n");
|
|
pr_expected_config_param(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, "init_on_alloc");
|
|
}
|
|
free_page((unsigned long)val);
|
|
}
|
|
|
|
void lkdtm_SLAB_FREE_DOUBLE(void)
|
|
{
|
|
int *val;
|
|
|
|
val = kmem_cache_alloc(double_free_cache, GFP_KERNEL);
|
|
if (!val) {
|
|
pr_info("Unable to allocate double_free_cache memory.\n");
|
|
return;
|
|
}
|
|
|
|
/* Just make sure we got real memory. */
|
|
*val = 0x12345678;
|
|
pr_info("Attempting double slab free ...\n");
|
|
kmem_cache_free(double_free_cache, val);
|
|
kmem_cache_free(double_free_cache, val);
|
|
}
|
|
|
|
void lkdtm_SLAB_FREE_CROSS(void)
|
|
{
|
|
int *val;
|
|
|
|
val = kmem_cache_alloc(a_cache, GFP_KERNEL);
|
|
if (!val) {
|
|
pr_info("Unable to allocate a_cache memory.\n");
|
|
return;
|
|
}
|
|
|
|
/* Just make sure we got real memory. */
|
|
*val = 0x12345679;
|
|
pr_info("Attempting cross-cache slab free ...\n");
|
|
kmem_cache_free(b_cache, val);
|
|
}
|
|
|
|
void lkdtm_SLAB_FREE_PAGE(void)
|
|
{
|
|
unsigned long p = __get_free_page(GFP_KERNEL);
|
|
|
|
pr_info("Attempting non-Slab slab free ...\n");
|
|
kmem_cache_free(NULL, (void *)p);
|
|
free_page(p);
|
|
}
|
|
|
|
/*
|
|
* We have constructors to keep the caches distinctly separated without
|
|
* needing to boot with "slab_nomerge".
|
|
*/
|
|
static void ctor_double_free(void *region)
|
|
{ }
|
|
static void ctor_a(void *region)
|
|
{ }
|
|
static void ctor_b(void *region)
|
|
{ }
|
|
|
|
void __init lkdtm_heap_init(void)
|
|
{
|
|
double_free_cache = kmem_cache_create("lkdtm-heap-double_free",
|
|
64, 0, 0, ctor_double_free);
|
|
a_cache = kmem_cache_create("lkdtm-heap-a", 64, 0, 0, ctor_a);
|
|
b_cache = kmem_cache_create("lkdtm-heap-b", 64, 0, 0, ctor_b);
|
|
}
|
|
|
|
void __exit lkdtm_heap_exit(void)
|
|
{
|
|
kmem_cache_destroy(double_free_cache);
|
|
kmem_cache_destroy(a_cache);
|
|
kmem_cache_destroy(b_cache);
|
|
}
|