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Commit b5484527 authored by Kees Cook's avatar Kees Cook
Browse files

lkdtm: split atomic test into over and underflow 



Each direction of the atomic wrapping should be individually testable.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent aa981a66

drivers/misc/lkdtm_core.c

+20 −6
Original line number Diff line number Diff line
@@ -111,7 +111,8 @@ enum ctype { 
	CT_WRITE_RO,

	CT_WRITE_RO_AFTER_INIT,

	CT_WRITE_KERN,

	CT_WRAP_ATOMIC,

	CT_ATOMIC_UNDERFLOW,

	CT_ATOMIC_OVERFLOW,

	CT_USERCOPY_HEAP_SIZE_TO,

	CT_USERCOPY_HEAP_SIZE_FROM,

	CT_USERCOPY_HEAP_FLAG_TO,
@@ -161,7 +162,8 @@ static char* cp_type[] = { 
	"WRITE_RO",

	"WRITE_RO_AFTER_INIT",

	"WRITE_KERN",

	"WRAP_ATOMIC",

	"ATOMIC_UNDERFLOW",

	"ATOMIC_OVERFLOW",

	"USERCOPY_HEAP_SIZE_TO",

	"USERCOPY_HEAP_SIZE_FROM",

	"USERCOPY_HEAP_FLAG_TO",
@@ -911,13 +913,25 @@ static void lkdtm_do_action(enum ctype which) 
		do_overwritten();

		break;

	}

	case CT_WRAP_ATOMIC: {

	case CT_ATOMIC_UNDERFLOW: {

		atomic_t under = ATOMIC_INIT(INT_MIN);

		atomic_t over = ATOMIC_INIT(INT_MAX);



		pr_info("attempting atomic underflow\n");

		pr_info("attempting good atomic increment\n");

		atomic_inc(&under);

		atomic_dec(&under);



		pr_info("attempting bad atomic underflow\n");

		atomic_dec(&under);

		pr_info("attempting atomic overflow\n");

		break;

	}

	case CT_ATOMIC_OVERFLOW: {

		atomic_t over = ATOMIC_INIT(INT_MAX);



		pr_info("attempting good atomic decrement\n");

		atomic_dec(&over);

		atomic_inc(&over);



		pr_info("attempting bad atomic overflow\n");

		atomic_inc(&over);



		return;