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 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);
}
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);
}
/*
* With 32-bit mode, a bounds directory is 4MB, and the size of each
* bounds table is 16KB. With 64-bit mode, a bounds directory is 2GB,
* and the size of each bounds table is 4MB.
*/
static int allocate_bt(struct mm_struct *mm, long __user *bd_entry)
{
unsigned long expected_old_val = 0;
unsigned long actual_old_val = 0;
unsigned long bt_addr;
unsigned long bd_new_entry;
int ret = 0;
/*
* Carve the virtual space out of userspace for the new
* bounds table:
*/
bt_addr = mpx_mmap(mpx_bt_size_bytes(mm));
if (IS_ERR((void *)bt_addr))
return PTR_ERR((void *)bt_addr);
/*
* Set the valid flag (kinda like _PAGE_PRESENT in a pte)
*/
bd_new_entry = bt_addr | MPX_BD_ENTRY_VALID_FLAG;
/*
* Go poke the address of the new bounds table in to the
* bounds directory entry out in userspace memory. Note:
* we may race with another CPU instantiating the same table.
* In that case the cmpxchg will see an unexpected
* 'actual_old_val'.
*
* This can fault, but that's OK because we do not hold
* mmap_sem at this point, unlike some of the other part
* of the MPX code that have to pagefault_disable().
*/
ret = mpx_cmpxchg_bd_entry(mm, &actual_old_val, bd_entry,
expected_old_val, bd_new_entry);
if (ret)
goto out_unmap;
/*
* The user_atomic_cmpxchg_inatomic() will only return nonzero
* for faults, *not* if the cmpxchg itself fails. Now we must
* verify that the cmpxchg itself completed successfully.
*/
/*
* We expected an empty 'expected_old_val', but instead found
* an apparently valid entry. Assume we raced with another
* thread to instantiate this table and desclare succecss.
*/
if (actual_old_val & MPX_BD_ENTRY_VALID_FLAG) {
ret = 0;
goto out_unmap;
}
/*
* We found a non-empty bd_entry but it did not have the
* VALID_FLAG set. Return an error which will result in
* a SEGV since this probably means that somebody scribbled
* some invalid data in to a bounds table.
*/
if (expected_old_val != actual_old_val) {
ret = -EINVAL;
goto out_unmap;
}
trace_mpx_new_bounds_table(bt_addr);
return 0;
out_unmap:
vm_munmap(bt_addr, mpx_bt_size_bytes(mm));
return ret;
}
static void lkdtm_do_action(enum ctype which)
{
switch (which) {
case CT_PANIC:
panic("dumptest");
break;
case CT_BUG:
BUG();
break;
case CT_WARNING:
WARN_ON(1);
break;
case CT_EXCEPTION:
*((int *) 0) = 0;
break;
case CT_LOOP:
for (;;)
;
break;
case CT_OVERFLOW:
(void) recursive_loop(recur_count);
break;
case CT_CORRUPT_STACK:
corrupt_stack();
break;
case CT_UNALIGNED_LOAD_STORE_WRITE: {
static u8 data[5] __attribute__((aligned(4))) = {1, 2,
3, 4, 5};
u32 *p;
u32 val = 0x12345678;
p = (u32 *)(data + 1);
if (*p == 0)
val = 0x87654321;
*p = val;
break;
}
case CT_OVERWRITE_ALLOCATION: {
size_t len = 1020;
u32 *data = kmalloc(len, GFP_KERNEL);
data[1024 / sizeof(u32)] = 0x12345678;
kfree(data);
break;
}
case CT_WRITE_AFTER_FREE: {
size_t len = 1024;
u32 *data = kmalloc(len, GFP_KERNEL);
kfree(data);
schedule();
memset(data, 0x78, len);
break;
}
case CT_SOFTLOCKUP:
preempt_disable();
for (;;)
cpu_relax();
break;
case CT_HARDLOCKUP:
local_irq_disable();
for (;;)
cpu_relax();
break;
case CT_SPINLOCKUP:
/* Must be called twice to trigger. */
spin_lock(&lock_me_up);
/* Let sparse know we intended to exit holding the lock. */
__release(&lock_me_up);
break;
case CT_HUNG_TASK:
set_current_state(TASK_UNINTERRUPTIBLE);
schedule();
break;
case CT_EXEC_DATA:
execute_location(data_area);
break;
case CT_EXEC_STACK: {
u8 stack_area[EXEC_SIZE];
execute_location(stack_area);
break;
}
case CT_EXEC_KMALLOC: {
u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL);
execute_location(kmalloc_area);
kfree(kmalloc_area);
break;
}
case CT_EXEC_VMALLOC: {
u32 *vmalloc_area = vmalloc(EXEC_SIZE);
execute_location(vmalloc_area);
vfree(vmalloc_area);
break;
}
case CT_EXEC_USERSPACE: {
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);
break;
}
case CT_ACCESS_USERSPACE: {
unsigned long user_addr, tmp;
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;
}
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);
break;
}
case CT_WRITE_RO: {
unsigned long *ptr;
ptr = (unsigned long *)&rodata;
pr_info("attempting bad write at %p\n", ptr);
*ptr ^= 0xabcd1234;
break;
}
case CT_WRITE_KERN: {
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();
break;
}
case CT_NONE:
default:
break;
}
}
int munmap(void *addr, size_t len){
int ret;
blocking_notifier_call_chain(&munmap_notifier, 0, addr);
ret = vm_munmap((unsigned long)addr, len);
return ret;
}
static int __init test_user_copy_init(void)
{
int ret = 0;
char *kmem;
char __user *usermem;
char *bad_usermem;
unsigned long user_addr;
unsigned long value = 0x5A;
kmem = kmalloc(PAGE_SIZE * 2, GFP_KERNEL);
if (!kmem)
return -ENOMEM;
user_addr = vm_mmap(NULL, 0, PAGE_SIZE * 2,
PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_ANONYMOUS | MAP_PRIVATE, 0);
if (user_addr >= (unsigned long)(TASK_SIZE)) {
pr_warn("Failed to allocate user memory\n");
kfree(kmem);
return -ENOMEM;
}
usermem = (char __user *)user_addr;
bad_usermem = (char *)user_addr;
/* Legitimate usage: none of these should fail. */
ret |= test(copy_from_user(kmem, usermem, PAGE_SIZE),
"legitimate copy_from_user failed");
ret |= test(copy_to_user(usermem, kmem, PAGE_SIZE),
"legitimate copy_to_user failed");
ret |= test(get_user(value, (unsigned long __user *)usermem),
"legitimate get_user failed");
ret |= test(put_user(value, (unsigned long __user *)usermem),
"legitimate put_user failed");
/* Invalid usage: none of these should succeed. */
ret |= test(!copy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE),
PAGE_SIZE),
"illegal all-kernel copy_from_user passed");
ret |= test(!copy_from_user(bad_usermem, (char __user *)kmem,
PAGE_SIZE),
"illegal reversed copy_from_user passed");
ret |= test(!copy_to_user((char __user *)kmem, kmem + PAGE_SIZE,
PAGE_SIZE),
"illegal all-kernel copy_to_user passed");
ret |= test(!copy_to_user((char __user *)kmem, bad_usermem,
PAGE_SIZE),
"illegal reversed copy_to_user passed");
ret |= test(!get_user(value, (unsigned long __user *)kmem),
"illegal get_user passed");
ret |= test(!put_user(value, (unsigned long __user *)kmem),
"illegal put_user passed");
vm_munmap(user_addr, PAGE_SIZE * 2);
kfree(kmem);
if (ret == 0) {
pr_info("tests passed.\n");
return 0;
}
return -EINVAL;
}
static int __init test_user_copy_init(void)
{
int ret = 0;
char *kmem;
char __user *usermem;
char *bad_usermem;
unsigned long user_addr;
u8 val_u8;
u16 val_u16;
u32 val_u32;
#ifdef TEST_U64
u64 val_u64;
#endif
kmem = kmalloc(PAGE_SIZE * 2, GFP_KERNEL);
if (!kmem)
return -ENOMEM;
user_addr = vm_mmap(NULL, 0, PAGE_SIZE * 2,
PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_ANONYMOUS | MAP_PRIVATE, 0);
if (user_addr >= (unsigned long)(TASK_SIZE)) {
pr_warn("Failed to allocate user memory\n");
kfree(kmem);
return -ENOMEM;
}
usermem = (char __user *)user_addr;
bad_usermem = (char *)user_addr;
/*
* Legitimate usage: none of these copies should fail.
*/
memset(kmem, 0x3a, PAGE_SIZE * 2);
ret |= test(copy_to_user(usermem, kmem, PAGE_SIZE),
"legitimate copy_to_user failed");
memset(kmem, 0x0, PAGE_SIZE);
ret |= test(copy_from_user(kmem, usermem, PAGE_SIZE),
"legitimate copy_from_user failed");
ret |= test(memcmp(kmem, kmem + PAGE_SIZE, PAGE_SIZE),
"legitimate usercopy failed to copy data");
#define test_legit(size, check) \
do { \
val_##size = check; \
ret |= test(put_user(val_##size, (size __user *)usermem), \
"legitimate put_user (" #size ") failed"); \
val_##size = 0; \
ret |= test(get_user(val_##size, (size __user *)usermem), \
"legitimate get_user (" #size ") failed"); \
ret |= test(val_##size != check, \
"legitimate get_user (" #size ") failed to do copy"); \
if (val_##size != check) { \
pr_info("0x%llx != 0x%llx\n", \
(unsigned long long)val_##size, \
(unsigned long long)check); \
} \
} while (0)
test_legit(u8, 0x5a);
test_legit(u16, 0x5a5b);
test_legit(u32, 0x5a5b5c5d);
#ifdef TEST_U64
test_legit(u64, 0x5a5b5c5d6a6b6c6d);
#endif
#undef test_legit
/*
* Invalid usage: none of these copies should succeed.
*/
/* Prepare kernel memory with check values. */
memset(kmem, 0x5a, PAGE_SIZE);
memset(kmem + PAGE_SIZE, 0, PAGE_SIZE);
/* Reject kernel-to-kernel copies through copy_from_user(). */
ret |= test(!copy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE),
PAGE_SIZE),
"illegal all-kernel copy_from_user passed");
/* Destination half of buffer should have been zeroed. */
ret |= test(memcmp(kmem + PAGE_SIZE, kmem, PAGE_SIZE),
"zeroing failure for illegal all-kernel copy_from_user");
#if 0
/*
* When running with SMAP/PAN/etc, this will Oops the kernel
* due to the zeroing of userspace memory on failure. This needs
* to be tested in LKDTM instead, since this test module does not
* expect to explode.
*/
ret |= test(!copy_from_user(bad_usermem, (char __user *)kmem,
PAGE_SIZE),
"illegal reversed copy_from_user passed");
#endif
ret |= test(!copy_to_user((char __user *)kmem, kmem + PAGE_SIZE,
PAGE_SIZE),
"illegal all-kernel copy_to_user passed");
ret |= test(!copy_to_user((char __user *)kmem, bad_usermem,
PAGE_SIZE),
"illegal reversed copy_to_user passed");
#define test_illegal(size, check) \
do { \
val_##size = (check); \
ret |= test(!get_user(val_##size, (size __user *)kmem), \
"illegal get_user (" #size ") passed"); \
ret |= test(val_##size != (size)0, \
"zeroing failure for illegal get_user (" #size ")"); \
if (val_##size != (size)0) { \
pr_info("0x%llx != 0\n", \
(unsigned long long)val_##size); \
} \
ret |= test(!put_user(val_##size, (size __user *)kmem), \
"illegal put_user (" #size ") passed"); \
} while (0)
test_illegal(u8, 0x5a);
test_illegal(u16, 0x5a5b);
test_illegal(u32, 0x5a5b5c5d);
#ifdef TEST_U64
test_illegal(u64, 0x5a5b5c5d6a6b6c6d);
#endif
#undef test_illegal
vm_munmap(user_addr, PAGE_SIZE * 2);
kfree(kmem);
if (ret == 0) {
pr_info("tests passed.\n");
return 0;
}
return -EINVAL;
}
