lkdtm: split memory permissions tests to separate file
This splits the EXEC_*, WRITE_* and related tests into the new lkdtm_perms.c
file to help separate things better for readability.
Signed-off-by: Kees Cook <keescook@chromium.org>
diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c
index 7437692..0b3e377 100644
--- a/drivers/misc/lkdtm_core.c
+++ b/drivers/misc/lkdtm_core.c
@@ -44,9 +44,6 @@
#include <linux/slab.h>
#include <scsi/scsi_cmnd.h>
#include <linux/debugfs.h>
-#include <linux/vmalloc.h>
-#include <linux/mman.h>
-#include <asm/cacheflush.h>
#ifdef CONFIG_IDE
#include <linux/ide.h>
@@ -67,7 +64,6 @@
#define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2)
#define DEFAULT_COUNT 10
-#define EXEC_SIZE 64
enum cname {
CN_INVALID,
@@ -191,11 +187,6 @@
static DEFINE_SPINLOCK(count_lock);
static DEFINE_SPINLOCK(lock_me_up);
-static u8 data_area[EXEC_SIZE];
-
-static const unsigned long rodata = 0xAA55AA55;
-static unsigned long ro_after_init __ro_after_init = 0x55AA5500;
-
module_param(recur_count, int, 0644);
MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
module_param(cpoint_name, charp, 0444);
@@ -348,18 +339,6 @@
return recursive_loop(remaining - 1);
}
-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 corrupt_stack(void)
{
/* Use default char array length that triggers stack protection. */
@@ -368,38 +347,6 @@
memset((void *)data, 0, 64);
}
-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) {
- 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();
-}
-
-
static void lkdtm_do_action(enum ctype which)
{
switch (which) {
@@ -577,116 +524,35 @@
schedule();
break;
case CT_EXEC_DATA:
- execute_location(data_area, true);
+ lkdtm_EXEC_DATA();
break;
- case CT_EXEC_STACK: {
- u8 stack_area[EXEC_SIZE];
- execute_location(stack_area, true);
+ case CT_EXEC_STACK:
+ lkdtm_EXEC_STACK();
break;
- }
- case CT_EXEC_KMALLOC: {
- u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL);
- execute_location(kmalloc_area, true);
- kfree(kmalloc_area);
+ case CT_EXEC_KMALLOC:
+ lkdtm_EXEC_KMALLOC();
break;
- }
- case CT_EXEC_VMALLOC: {
- u32 *vmalloc_area = vmalloc(EXEC_SIZE);
- execute_location(vmalloc_area, true);
- vfree(vmalloc_area);
+ case CT_EXEC_VMALLOC:
+ lkdtm_EXEC_VMALLOC();
break;
- }
case CT_EXEC_RODATA:
- execute_location(lkdtm_rodata_do_nothing, false);
+ lkdtm_EXEC_RODATA();
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);
+ case CT_EXEC_USERSPACE:
+ lkdtm_EXEC_USERSPACE();
break;
- }
- case CT_ACCESS_USERSPACE: {
- 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);
-
+ case CT_ACCESS_USERSPACE:
+ lkdtm_ACCESS_USERSPACE();
break;
- }
- case CT_WRITE_RO: {
- /* 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;
-
+ case CT_WRITE_RO:
+ lkdtm_WRITE_RO();
break;
- }
- case CT_WRITE_RO_AFTER_INIT: {
- 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);
- break;
- }
-
- pr_info("attempting bad ro_after_init write at %p\n", ptr);
- *ptr ^= 0xabcd1234;
-
+ case CT_WRITE_RO_AFTER_INIT:
+ lkdtm_WRITE_RO_AFTER_INIT();
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();
+ case CT_WRITE_KERN:
+ lkdtm_WRITE_KERN();
break;
- }
case CT_ATOMIC_UNDERFLOW: {
atomic_t under = ATOMIC_INIT(INT_MIN);
@@ -1024,11 +890,9 @@
int i;
/* Handle test-specific initialization. */
+ lkdtm_perms_init();
lkdtm_usercopy_init();
- /* Make sure we can write to __ro_after_init values during __init */
- ro_after_init |= 0xAA;
-
/* Register debugfs interface */
lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
if (!lkdtm_debugfs_root) {