mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-20 14:16:02 +00:00
![Kees Cook](/assets/img/avatar_default.png)
When building under W=1, the lack of lkdtm.h in lkdtm_usercopy.c and lkdtm_rodata.c was discovered. This fixes the issue and consolidates the common header and the pr_fmt macro for simplicity and regularity across each test source file. Signed-off-by: Kees Cook <keescook@chromium.org>
199 lines
4.6 KiB
C
199 lines
4.6 KiB
C
/*
|
|
* This is for all the tests related to validating kernel memory
|
|
* permissions: non-executable regions, non-writable regions, and
|
|
* even non-readable regions.
|
|
*/
|
|
#include "lkdtm.h"
|
|
#include <linux/slab.h>
|
|
#include <linux/vmalloc.h>
|
|
#include <linux/mman.h>
|
|
#include <linux/uaccess.h>
|
|
#include <asm/cacheflush.h>
|
|
|
|
/* Whether or not to fill the target memory area with do_nothing(). */
|
|
#define CODE_WRITE true
|
|
#define CODE_AS_IS false
|
|
|
|
/* How many bytes to copy to be sure we've copied enough of do_nothing(). */
|
|
#define EXEC_SIZE 64
|
|
|
|
/* This is non-const, so it will end up in the .data section. */
|
|
static u8 data_area[EXEC_SIZE];
|
|
|
|
/* This is cost, so it will end up in the .rodata section. */
|
|
static const unsigned long rodata = 0xAA55AA55;
|
|
|
|
/* This is marked __ro_after_init, so it should ultimately be .rodata. */
|
|
static unsigned long ro_after_init __ro_after_init = 0x55AA5500;
|
|
|
|
/*
|
|
* This just returns to the caller. It is designed to be copied into
|
|
* non-executable memory regions.
|
|
*/
|
|
static void do_nothing(void)
|
|
{
|
|
return;
|
|
}
|
|
|
|
/* Must immediately follow do_nothing for size calculuations to work out. */
|
|
static void do_overwritten(void)
|
|
{
|
|
pr_info("do_overwritten wasn't overwritten!\n");
|
|
return;
|
|
}
|
|
|
|
static noinline void execute_location(void *dst, bool write)
|
|
{
|
|
void (*func)(void) = dst;
|
|
|
|
pr_info("attempting ok execution at %p\n", do_nothing);
|
|
do_nothing();
|
|
|
|
if (write == CODE_WRITE) {
|
|
memcpy(dst, do_nothing, EXEC_SIZE);
|
|
flush_icache_range((unsigned long)dst,
|
|
(unsigned long)dst + EXEC_SIZE);
|
|
}
|
|
pr_info("attempting bad execution at %p\n", func);
|
|
func();
|
|
}
|
|
|
|
static void execute_user_location(void *dst)
|
|
{
|
|
/* Intentionally crossing kernel/user memory boundary. */
|
|
void (*func)(void) = dst;
|
|
|
|
pr_info("attempting ok execution at %p\n", do_nothing);
|
|
do_nothing();
|
|
|
|
if (copy_to_user((void __user *)dst, do_nothing, EXEC_SIZE))
|
|
return;
|
|
flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE);
|
|
pr_info("attempting bad execution at %p\n", func);
|
|
func();
|
|
}
|
|
|
|
void lkdtm_WRITE_RO(void)
|
|
{
|
|
/* Explicitly cast away "const" for the test. */
|
|
unsigned long *ptr = (unsigned long *)&rodata;
|
|
|
|
pr_info("attempting bad rodata write at %p\n", ptr);
|
|
*ptr ^= 0xabcd1234;
|
|
}
|
|
|
|
void lkdtm_WRITE_RO_AFTER_INIT(void)
|
|
{
|
|
unsigned long *ptr = &ro_after_init;
|
|
|
|
/*
|
|
* Verify we were written to during init. Since an Oops
|
|
* is considered a "success", a failure is to just skip the
|
|
* real test.
|
|
*/
|
|
if ((*ptr & 0xAA) != 0xAA) {
|
|
pr_info("%p was NOT written during init!?\n", ptr);
|
|
return;
|
|
}
|
|
|
|
pr_info("attempting bad ro_after_init write at %p\n", ptr);
|
|
*ptr ^= 0xabcd1234;
|
|
}
|
|
|
|
void lkdtm_WRITE_KERN(void)
|
|
{
|
|
size_t size;
|
|
unsigned char *ptr;
|
|
|
|
size = (unsigned long)do_overwritten - (unsigned long)do_nothing;
|
|
ptr = (unsigned char *)do_overwritten;
|
|
|
|
pr_info("attempting bad %zu byte write at %p\n", size, ptr);
|
|
memcpy(ptr, (unsigned char *)do_nothing, size);
|
|
flush_icache_range((unsigned long)ptr, (unsigned long)(ptr + size));
|
|
|
|
do_overwritten();
|
|
}
|
|
|
|
void lkdtm_EXEC_DATA(void)
|
|
{
|
|
execute_location(data_area, CODE_WRITE);
|
|
}
|
|
|
|
void lkdtm_EXEC_STACK(void)
|
|
{
|
|
u8 stack_area[EXEC_SIZE];
|
|
execute_location(stack_area, CODE_WRITE);
|
|
}
|
|
|
|
void lkdtm_EXEC_KMALLOC(void)
|
|
{
|
|
u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL);
|
|
execute_location(kmalloc_area, CODE_WRITE);
|
|
kfree(kmalloc_area);
|
|
}
|
|
|
|
void lkdtm_EXEC_VMALLOC(void)
|
|
{
|
|
u32 *vmalloc_area = vmalloc(EXEC_SIZE);
|
|
execute_location(vmalloc_area, CODE_WRITE);
|
|
vfree(vmalloc_area);
|
|
}
|
|
|
|
void lkdtm_EXEC_RODATA(void)
|
|
{
|
|
execute_location(lkdtm_rodata_do_nothing, CODE_AS_IS);
|
|
}
|
|
|
|
void lkdtm_EXEC_USERSPACE(void)
|
|
{
|
|
unsigned long user_addr;
|
|
|
|
user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
|
|
PROT_READ | PROT_WRITE | PROT_EXEC,
|
|
MAP_ANONYMOUS | MAP_PRIVATE, 0);
|
|
if (user_addr >= TASK_SIZE) {
|
|
pr_warn("Failed to allocate user memory\n");
|
|
return;
|
|
}
|
|
execute_user_location((void *)user_addr);
|
|
vm_munmap(user_addr, PAGE_SIZE);
|
|
}
|
|
|
|
void lkdtm_ACCESS_USERSPACE(void)
|
|
{
|
|
unsigned long user_addr, tmp = 0;
|
|
unsigned long *ptr;
|
|
|
|
user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
|
|
PROT_READ | PROT_WRITE | PROT_EXEC,
|
|
MAP_ANONYMOUS | MAP_PRIVATE, 0);
|
|
if (user_addr >= TASK_SIZE) {
|
|
pr_warn("Failed to allocate user memory\n");
|
|
return;
|
|
}
|
|
|
|
if (copy_to_user((void __user *)user_addr, &tmp, sizeof(tmp))) {
|
|
pr_warn("copy_to_user failed\n");
|
|
vm_munmap(user_addr, PAGE_SIZE);
|
|
return;
|
|
}
|
|
|
|
ptr = (unsigned long *)user_addr;
|
|
|
|
pr_info("attempting bad read at %p\n", ptr);
|
|
tmp = *ptr;
|
|
tmp += 0xc0dec0de;
|
|
|
|
pr_info("attempting bad write at %p\n", ptr);
|
|
*ptr = tmp;
|
|
|
|
vm_munmap(user_addr, PAGE_SIZE);
|
|
}
|
|
|
|
void __init lkdtm_perms_init(void)
|
|
{
|
|
/* Make sure we can write to __ro_after_init values during __init */
|
|
ro_after_init |= 0xAA;
|
|
|
|
}
|