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[tip:locking/core] lkdtm: Convert to refcount_t testing

From tip-bot for Kees Cook <tipbot@zytor.com>
Newsgroups linux.kernel
Subject [tip:locking/core] lkdtm: Convert to refcount_t testing
Date 2017-02-10 09:50 +0100
Message-ID <t9f3Z-140-23@gated-at.bofh.it> (permalink)
References <t6VsJ-7S-9@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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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Thread

[PATCH 0/4] refcount_t followups... Kees Cook <keescook@chromium.org> - 2017-02-04 00:30 +0100
  [PATCH 2/4] lkdtm: convert to refcount_t testing Kees Cook <keescook@chromium.org> - 2017-02-04 00:30 +0100
    [tip:locking/core] lkdtm: Convert to refcount_t testing tip-bot for Kees Cook <tipbot@zytor.com> - 2017-02-10 09:50 +0100
  [PATCH 3/4] bug: Switch data corruption check to __must_check Kees Cook <keescook@chromium.org> - 2017-02-04 00:30 +0100
  [PATCH 1/4] refcount_t: fix Kconfig help Kees Cook <keescook@chromium.org> - 2017-02-04 00:30 +0100
  [PATCH 4/4] refcount: Report failures through CHECK_DATA_CORRUPTION Kees Cook <keescook@chromium.org> - 2017-02-04 00:30 +0100
    Re: [PATCH 4/4] refcount: Report failures through  CHECK_DATA_CORRUPTION Peter Zijlstra <peterz@infradead.org> - 2017-02-05 16:50 +0100
      Re: [PATCH 4/4] refcount: Report failures through CHECK_DATA_CORRUPTION Kees Cook <keescook@chromium.org> - 2017-02-06 00:40 +0100
        Re: [PATCH 4/4] refcount: Report failures through  CHECK_DATA_CORRUPTION Peter Zijlstra <peterz@infradead.org> - 2017-02-06 10:00 +0100
          Re: [PATCH 4/4] refcount: Report failures through CHECK_DATA_CORRUPTION Kees Cook <keescook@chromium.org> - 2017-02-06 18:00 +0100
            Re: [PATCH 4/4] refcount: Report failures through  CHECK_DATA_CORRUPTION Peter Zijlstra <peterz@infradead.org> - 2017-02-07 09:40 +0100
              Re: [kernel-hardening] Re: [PATCH 4/4] refcount: Report failures  through CHECK_DATA_CORRUPTION Mark Rutland <mark.rutland@arm.com> - 2017-02-07 12:20 +0100
                Re: [kernel-hardening] Re: [PATCH 4/4] refcount: Report failures  through CHECK_DATA_CORRUPTION Peter Zijlstra <peterz@infradead.org> - 2017-02-07 13:40 +0100
                Re: [kernel-hardening] Re: [PATCH 4/4] refcount: Report failures  through CHECK_DATA_CORRUPTION Mark Rutland <mark.rutland@arm.com> - 2017-02-07 15:00 +0100
                Re: [kernel-hardening] Re: [PATCH 4/4] refcount: Report failures  through CHECK_DATA_CORRUPTION Peter Zijlstra <peterz@infradead.org> - 2017-02-07 16:10 +0100
                Re: [kernel-hardening] Re: [PATCH 4/4] refcount: Report failures  through CHECK_DATA_CORRUPTION Mark Rutland <mark.rutland@arm.com> - 2017-02-07 17:10 +0100
                Re: [kernel-hardening] Re: [PATCH 4/4] refcount: Report failures  through CHECK_DATA_CORRUPTION Peter Zijlstra <peterz@infradead.org> - 2017-02-07 18:40 +0100
                Re: [kernel-hardening] Re: [PATCH 4/4] refcount: Report failures  through CHECK_DATA_CORRUPTION Mark Rutland <mark.rutland@arm.com> - 2017-02-07 19:00 +0100
                Re: [kernel-hardening] Re: [PATCH 4/4] refcount: Report failures  through CHECK_DATA_CORRUPTION Peter Zijlstra <peterz@infradead.org> - 2017-02-08 10:20 +0100
                Re: [kernel-hardening] Re: [PATCH 4/4] refcount: Report failures  through CHECK_DATA_CORRUPTION Peter Zijlstra <peterz@infradead.org> - 2017-02-08 10:50 +0100
                Re: [kernel-hardening] Re: [PATCH 4/4] refcount: Report failures  through CHECK_DATA_CORRUPTION Mark Rutland <mark.rutland@arm.com> - 2017-02-08 16:00 +0100
                Re: [kernel-hardening] Re: [PATCH 4/4] refcount: Report failures  through CHECK_DATA_CORRUPTION Kees Cook <keescook@chromium.org> - 2017-02-08 22:30 +0100
                Re: [kernel-hardening] Re: [PATCH 4/4] refcount: Report failures  through CHECK_DATA_CORRUPTION Peter Zijlstra <peterz@infradead.org> - 2017-02-09 11:30 +0100
                Re: [kernel-hardening] Re: [PATCH 4/4] refcount: Report failures  through CHECK_DATA_CORRUPTION Kees Cook <keescook@chromium.org> - 2017-02-11 00:40 +0100

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