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Message-Id: <1486164412-7338-3-git-send-email-keescook@chromium.org>
Date: Fri, 3 Feb 2017 15:26:50 -0800
From: Kees Cook <keescook@...omium.org>
To: Peter Zijlstra <peterz@...radead.org>
Cc: Kees Cook <keescook@...omium.org>, elena.reshetova@...el.com,
gregkh@...uxfoundation.org, arnd@...db.de, tglx@...utronix.de,
mingo@...nel.org, h.peter.anvin@...el.com, will.deacon@....com,
dwindsor@...il.com, Hans Liljestrand <ishkamiel@...il.com>,
dhowells@...hat.com, linux-kernel@...r.kernel.org,
kernel-hardening@...ts.openwall.com
Subject: [PATCH 2/4] 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: Kees Cook <keescook@...omium.org>
---
drivers/misc/lkdtm.h | 8 +++--
drivers/misc/lkdtm_bugs.c | 87 +++++++++++++++++++++++++++++++++++++++--------
drivers/misc/lkdtm_core.c | 8 +++--
3 files changed, 85 insertions(+), 18 deletions(-)
diff --git a/drivers/misc/lkdtm.h b/drivers/misc/lkdtm.h
index cfa1039c62e7..67d27be60405 100644
--- a/drivers/misc/lkdtm.h
+++ b/drivers/misc/lkdtm.h
@@ -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);
diff --git a/drivers/misc/lkdtm_bugs.c b/drivers/misc/lkdtm_bugs.c
index bb3bb8ef5f44..e3f4cd8876b5 100644
--- a/drivers/misc/lkdtm_bugs.c
+++ b/drivers/misc/lkdtm_bugs.c
@@ -6,6 +6,7 @@
*/
#include "lkdtm.h"
#include <linux/list.h>
+#include <linux/refcount.h>
#include <linux/sched.h>
struct lkdtm_list {
@@ -134,28 +135,86 @@ 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)
diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c
index 4d44084071d8..b9a4cd4a9b68 100644
--- a/drivers/misc/lkdtm_core.c
+++ b/drivers/misc/lkdtm_core.c
@@ -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),
--
2.7.4
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