Commit ff86b300 authored by Kees Cook's avatar Kees Cook Committed by Ingo Molnar
Browse files

lkdtm: Convert to refcount_t testing 



Since we'll be using refcount_t instead of atomic_t for refcounting,
change the LKDTM tests to reflect the new interface and test conditions.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Hans Liljestrand <ishkamiel@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arnd@arndb.de
Cc: dhowells@redhat.com
Cc: dwindsor@gmail.com
Cc: elena.reshetova@intel.com
Cc: gregkh@linuxfoundation.org
Cc: h.peter.anvin@intel.com
Cc: kernel-hardening@lists.openwall.com
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1486164412-7338-3-git-send-email-keescook@chromium.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 10383aea

drivers/misc/lkdtm.h

+6 −2
Original line number Diff line number Diff line
@@ -19,8 +19,12 @@ void lkdtm_SOFTLOCKUP(void); 
void lkdtm_HARDLOCKUP(void);

void lkdtm_SPINLOCKUP(void);

void lkdtm_HUNG_TASK(void);

void lkdtm_ATOMIC_UNDERFLOW(void);

void lkdtm_ATOMIC_OVERFLOW(void);

void lkdtm_REFCOUNT_SATURATE_INC(void);

void lkdtm_REFCOUNT_SATURATE_ADD(void);

void lkdtm_REFCOUNT_ZERO_DEC(void);

void lkdtm_REFCOUNT_ZERO_INC(void);

void lkdtm_REFCOUNT_ZERO_SUB(void);

void lkdtm_REFCOUNT_ZERO_ADD(void);

void lkdtm_CORRUPT_LIST_ADD(void);

void lkdtm_CORRUPT_LIST_DEL(void);

drivers/misc/lkdtm_bugs.c

+73 −14
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
 */

#include "lkdtm.h"

#include <linux/list.h>

#include <linux/refcount.h>

#include <linux/sched.h>



struct lkdtm_list {
@@ -129,28 +130,86 @@ void lkdtm_HUNG_TASK(void) 
	schedule();

}



void lkdtm_ATOMIC_UNDERFLOW(void)

void lkdtm_REFCOUNT_SATURATE_INC(void)

{

	atomic_t under = ATOMIC_INIT(INT_MIN);

	refcount_t over = REFCOUNT_INIT(UINT_MAX - 1);



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

	atomic_inc(&under);

	atomic_dec(&under);

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

	refcount_dec(&over);

	refcount_inc(&over);



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

	atomic_dec(&under);

	pr_info("attempting bad refcount inc overflow\n");

	refcount_inc(&over);

	refcount_inc(&over);

	if (refcount_read(&over) == UINT_MAX)

		pr_err("Correctly stayed saturated, but no BUG?!\n");

	else

		pr_err("Fail: refcount wrapped\n");

}



void lkdtm_REFCOUNT_SATURATE_ADD(void)

{

	refcount_t over = REFCOUNT_INIT(UINT_MAX - 1);



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

	refcount_dec(&over);

	refcount_inc(&over);



	pr_info("attempting bad refcount add overflow\n");

	refcount_add(2, &over);

	if (refcount_read(&over) == UINT_MAX)

		pr_err("Correctly stayed saturated, but no BUG?!\n");

	else

		pr_err("Fail: refcount wrapped\n");

}



void lkdtm_REFCOUNT_ZERO_DEC(void)

{

	refcount_t zero = REFCOUNT_INIT(1);



	pr_info("attempting bad refcount decrement to zero\n");

	refcount_dec(&zero);

	if (refcount_read(&zero) == 0)

		pr_err("Stayed at zero, but no BUG?!\n");

	else

		pr_err("Fail: refcount went crazy\n");

}



void lkdtm_ATOMIC_OVERFLOW(void)

void lkdtm_REFCOUNT_ZERO_SUB(void)

{

	atomic_t over = ATOMIC_INIT(INT_MAX);

	refcount_t zero = REFCOUNT_INIT(1);



	pr_info("attempting bad refcount subtract past zero\n");

	if (!refcount_sub_and_test(2, &zero))

		pr_info("wrap attempt was noticed\n");

	if (refcount_read(&zero) == 1)

		pr_err("Correctly stayed above 0, but no BUG?!\n");

	else

		pr_err("Fail: refcount wrapped\n");

}



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

	atomic_dec(&over);

	atomic_inc(&over);

void lkdtm_REFCOUNT_ZERO_INC(void)

{

	refcount_t zero = REFCOUNT_INIT(0);



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

	atomic_inc(&over);

	pr_info("attempting bad refcount increment from zero\n");

	refcount_inc(&zero);

	if (refcount_read(&zero) == 0)

		pr_err("Stayed at zero, but no BUG?!\n");

	else

		pr_err("Fail: refcount went past zero\n");

}



void lkdtm_REFCOUNT_ZERO_ADD(void)

{

	refcount_t zero = REFCOUNT_INIT(0);



	pr_info("attempting bad refcount addition from zero\n");

	refcount_add(2, &zero);

	if (refcount_read(&zero) == 0)

		pr_err("Stayed at zero, but no BUG?!\n");

	else

		pr_err("Fail: refcount went past zero\n");

}



void lkdtm_CORRUPT_LIST_ADD(void)

drivers/misc/lkdtm_core.c

+6 −2
Original line number Diff line number Diff line
@@ -220,8 +220,12 @@ struct crashtype crashtypes[] = { 
	CRASHTYPE(WRITE_RO),

	CRASHTYPE(WRITE_RO_AFTER_INIT),

	CRASHTYPE(WRITE_KERN),

	CRASHTYPE(ATOMIC_UNDERFLOW),

	CRASHTYPE(ATOMIC_OVERFLOW),

	CRASHTYPE(REFCOUNT_SATURATE_INC),

	CRASHTYPE(REFCOUNT_SATURATE_ADD),

	CRASHTYPE(REFCOUNT_ZERO_DEC),

	CRASHTYPE(REFCOUNT_ZERO_INC),

	CRASHTYPE(REFCOUNT_ZERO_SUB),

	CRASHTYPE(REFCOUNT_ZERO_ADD),

	CRASHTYPE(USERCOPY_HEAP_SIZE_TO),

	CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),

	CRASHTYPE(USERCOPY_HEAP_FLAG_TO),

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