Commit dc6a7eff authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

Merge tag 'lkdtm-next' of... 

Merge tag 'lkdtm-next' of https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux into char-misc-next

Kees writes:

lkdtm updates for -next

- Test for new usercopy memory regions
- avoid GCC 12 warnings
- update expected CONFIGs for selftests

* tag 'lkdtm-next' of https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  lkdtm/heap: Hide allocation size from -Warray-bounds
  selftests/lkdtm: Add configs for stackleak and "after free" tests
  lkdtm/usercopy: Check vmalloc and >0-order folios
  lkdtm/usercopy: Rename "heap" to "slab"
  lkdtm: cfi: Fix type width for masking PAC bits
parents bab6ffa2 f260fd59

drivers/misc/lkdtm/heap.c

+1 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ static void lkdtm_SLAB_LINEAR_OVERFLOW(void) 
		return;



	pr_info("Attempting slab linear overflow ...\n");

	OPTIMIZER_HIDE_VAR(data);

	data[1024 / sizeof(u32)] = 0x12345678;

	kfree(data);

}

drivers/misc/lkdtm/usercopy.c

+98 −15
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
 */

#include "lkdtm.h"

#include <linux/slab.h>

#include <linux/highmem.h>

#include <linux/vmalloc.h>

#include <linux/sched/task_stack.h>

#include <linux/mman.h>
@@ -130,7 +131,7 @@ static noinline void do_usercopy_stack(bool to_user, bool bad_frame) 
 * This checks for whole-object size validation with hardened usercopy,

 * with or without usercopy whitelisting.

 */

static void do_usercopy_heap_size(bool to_user)

static void do_usercopy_slab_size(bool to_user)

{

	unsigned long user_addr;

	unsigned char *one, *two;
@@ -196,9 +197,9 @@ static void do_usercopy_heap_size(bool to_user) 


/*

 * This checks for the specific whitelist window within an object. If this

 * test passes, then do_usercopy_heap_size() tests will pass too.

 * test passes, then do_usercopy_slab_size() tests will pass too.

 */

static void do_usercopy_heap_whitelist(bool to_user)

static void do_usercopy_slab_whitelist(bool to_user)

{

	unsigned long user_alloc;

	unsigned char *buf = NULL;
@@ -272,24 +273,24 @@ static void do_usercopy_heap_whitelist(bool to_user) 
}



/* Callable tests. */

static void lkdtm_USERCOPY_HEAP_SIZE_TO(void)

static void lkdtm_USERCOPY_SLAB_SIZE_TO(void)

{

	do_usercopy_heap_size(true);

	do_usercopy_slab_size(true);

}



static void lkdtm_USERCOPY_HEAP_SIZE_FROM(void)

static void lkdtm_USERCOPY_SLAB_SIZE_FROM(void)

{

	do_usercopy_heap_size(false);

	do_usercopy_slab_size(false);

}



static void lkdtm_USERCOPY_HEAP_WHITELIST_TO(void)

static void lkdtm_USERCOPY_SLAB_WHITELIST_TO(void)

{

	do_usercopy_heap_whitelist(true);

	do_usercopy_slab_whitelist(true);

}



static void lkdtm_USERCOPY_HEAP_WHITELIST_FROM(void)

static void lkdtm_USERCOPY_SLAB_WHITELIST_FROM(void)

{

	do_usercopy_heap_whitelist(false);

	do_usercopy_slab_whitelist(false);

}



static void lkdtm_USERCOPY_STACK_FRAME_TO(void)
@@ -341,6 +342,86 @@ static void lkdtm_USERCOPY_KERNEL(void) 
	vm_munmap(user_addr, PAGE_SIZE);

}



/*

 * This expects "kaddr" to point to a PAGE_SIZE allocation, which means

 * a more complete test that would include copy_from_user() would risk

 * memory corruption. Just test copy_to_user() here, as that exercises

 * almost exactly the same code paths.

 */

static void do_usercopy_page_span(const char *name, void *kaddr)

{

	unsigned long uaddr;



	uaddr = vm_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_WRITE,

			MAP_ANONYMOUS | MAP_PRIVATE, 0);

	if (uaddr >= TASK_SIZE) {

		pr_warn("Failed to allocate user memory\n");

		return;

	}



	/* Initialize contents. */

	memset(kaddr, 0xAA, PAGE_SIZE);



	/* Bump the kaddr forward to detect a page-spanning overflow. */

	kaddr += PAGE_SIZE / 2;



	pr_info("attempting good copy_to_user() from kernel %s: %px\n",

		name, kaddr);

	if (copy_to_user((void __user *)uaddr, kaddr,

			 unconst + (PAGE_SIZE / 2))) {

		pr_err("copy_to_user() failed unexpectedly?!\n");

		goto free_user;

	}



	pr_info("attempting bad copy_to_user() from kernel %s: %px\n",

		name, kaddr);

	if (copy_to_user((void __user *)uaddr, kaddr, unconst + PAGE_SIZE)) {

		pr_warn("Good, copy_to_user() failed, but lacked Oops(?!)\n");

		goto free_user;

	}



	pr_err("FAIL: bad copy_to_user() not detected!\n");

	pr_expected_config_param(CONFIG_HARDENED_USERCOPY, "hardened_usercopy");



free_user:

	vm_munmap(uaddr, PAGE_SIZE);

}



static void lkdtm_USERCOPY_VMALLOC(void)

{

	void *addr;



	addr = vmalloc(PAGE_SIZE);

	if (!addr) {

		pr_err("vmalloc() failed!?\n");

		return;

	}

	do_usercopy_page_span("vmalloc", addr);

	vfree(addr);

}



static void lkdtm_USERCOPY_FOLIO(void)

{

	struct folio *folio;

	void *addr;



	/*

	 * FIXME: Folio checking currently misses 0-order allocations, so

	 * allocate and bump forward to the last page.

	 */

	folio = folio_alloc(GFP_KERNEL | __GFP_ZERO, 1);

	if (!folio) {

		pr_err("folio_alloc() failed!?\n");

		return;

	}

	addr = folio_address(folio);

	if (addr)

		do_usercopy_page_span("folio", addr + PAGE_SIZE);

	else

		pr_err("folio_address() failed?!\n");

	folio_put(folio);

}



void __init lkdtm_usercopy_init(void)

{

	/* Prepare cache that lacks SLAB_USERCOPY flag. */
@@ -358,13 +439,15 @@ void __exit lkdtm_usercopy_exit(void) 
}



static struct crashtype crashtypes[] = {

	CRASHTYPE(USERCOPY_HEAP_SIZE_TO),

	CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),

	CRASHTYPE(USERCOPY_HEAP_WHITELIST_TO),

	CRASHTYPE(USERCOPY_HEAP_WHITELIST_FROM),

	CRASHTYPE(USERCOPY_SLAB_SIZE_TO),

	CRASHTYPE(USERCOPY_SLAB_SIZE_FROM),

	CRASHTYPE(USERCOPY_SLAB_WHITELIST_TO),

	CRASHTYPE(USERCOPY_SLAB_WHITELIST_FROM),

	CRASHTYPE(USERCOPY_STACK_FRAME_TO),

	CRASHTYPE(USERCOPY_STACK_FRAME_FROM),

	CRASHTYPE(USERCOPY_STACK_BEYOND),

	CRASHTYPE(USERCOPY_VMALLOC),

	CRASHTYPE(USERCOPY_FOLIO),

	CRASHTYPE(USERCOPY_KERNEL),

};

tools/testing/selftests/lkdtm/config

+2 −0
Original line number Diff line number Diff line
@@ -2,8 +2,10 @@ CONFIG_LKDTM=y 
CONFIG_DEBUG_LIST=y

CONFIG_SLAB_FREELIST_HARDENED=y

CONFIG_FORTIFY_SOURCE=y

CONFIG_GCC_PLUGIN_STACKLEAK=y

CONFIG_HARDENED_USERCOPY=y

CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT=y

CONFIG_INIT_ON_FREE_DEFAULT_ON=y

CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y

CONFIG_UBSAN=y

CONFIG_UBSAN_BOUNDS=y

tools/testing/selftests/lkdtm/tests.txt

+4 −4
Original line number Diff line number Diff line
@@ -64,10 +64,10 @@ REFCOUNT_DEC_AND_TEST_SATURATED Saturation detected: still saturated 
REFCOUNT_SUB_AND_TEST_SATURATED Saturation detected: still saturated

#REFCOUNT_TIMING timing only

#ATOMIC_TIMING timing only

USERCOPY_HEAP_SIZE_TO

USERCOPY_HEAP_SIZE_FROM

USERCOPY_HEAP_WHITELIST_TO

USERCOPY_HEAP_WHITELIST_FROM

USERCOPY_SLAB_SIZE_TO

USERCOPY_SLAB_SIZE_FROM

USERCOPY_SLAB_WHITELIST_TO

USERCOPY_SLAB_WHITELIST_FROM

USERCOPY_STACK_FRAME_TO

USERCOPY_STACK_FRAME_FROM

USERCOPY_STACK_BEYOND