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Subject[tip:locking/core] lkdtm: Convert to refcount_t testing
Commit-ID:  ff86b30010eee8249dc244ce1868b886bbee6449
Gitweb: http://git.kernel.org/tip/ff86b30010eee8249dc244ce1868b886bbee6449
Author: Kees Cook <keescook@chromium.org>
AuthorDate: Fri, 3 Feb 2017 15:26:50 -0800
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 10 Feb 2017 09:04:20 +0100

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@chromium.org>
Signed-off-by: Peter 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: Ingo Molnar <mingo@kernel.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 cfa1039..67d27be 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 91edd0b..cba0837 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 {
@@ -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)
diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c
index 7eeb71a..16e4cf1 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),
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