linux/drivers/misc/lkdtm_heap.c
Ingo Molnar 5b825c3af1 sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>
Add #include <linux/cred.h> dependencies to all .c files rely on sched.h
doing that for them.

Note that even if the count where we need to add extra headers seems high,
it's still a net win, because <linux/sched.h> is included in over
2,200 files ...

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:31 +01:00

144 lines
3.2 KiB
C

/*
* 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/sched.h>
/*
* 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_OVERWRITE_ALLOCATION(void)
{
size_t len = 1020;
u32 *data = kmalloc(len, GFP_KERNEL);
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);
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 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) {
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);
BUG();
}
pr_info("Memory was not poisoned\n");
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);
BUG();
}
pr_info("Buddy page was not poisoned\n");
kfree(val);
}