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From: Sami Tolvanen <samitolvanen@google.com>
To: Kees Cook <keescook@chromium.org>
Cc: Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Will Deacon <will@kernel.org>, Jessica Yu <jeyu@kernel.org>,
	Arnd Bergmann <arnd@arndb.de>, Tejun Heo <tj@kernel.org>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Christoph Hellwig <hch@infradead.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Sedat Dilek <sedat.dilek@gmail.com>,
	bpf@vger.kernel.org, linux-hardening@vger.kernel.org,
	linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kbuild@vger.kernel.org, linux-pci@vger.kernel.org,
	linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com,
	Sami Tolvanen <samitolvanen@google.com>
Subject: [PATCH v4 06/17] kthread: use WARN_ON_FUNCTION_MISMATCH
Date: Wed, 31 Mar 2021 14:27:10 -0700	[thread overview]
Message-ID: <20210331212722.2746212-7-samitolvanen@google.com> (raw)
In-Reply-To: <20210331212722.2746212-1-samitolvanen@google.com>

With CONFIG_CFI_CLANG, a callback function passed to
__kthread_queue_delayed_work from a module points to a jump table
entry defined in the module instead of the one used in the core
kernel, which breaks function address equality in this check:

  WARN_ON_ONCE(timer->function != ktead_delayed_work_timer_fn);

Use WARN_ON_FUNCTION_MISMATCH() instead to disable the warning
when CFI and modules are both enabled.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
 kernel/kthread.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/kthread.c b/kernel/kthread.c
index 1578973c5740..a1972eba2917 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -963,7 +963,8 @@ static void __kthread_queue_delayed_work(struct kthread_worker *worker,
 	struct timer_list *timer = &dwork->timer;
 	struct kthread_work *work = &dwork->work;
 
-	WARN_ON_ONCE(timer->function != kthread_delayed_work_timer_fn);
+	WARN_ON_FUNCTION_MISMATCH(timer->function,
+				  kthread_delayed_work_timer_fn);
 
 	/*
 	 * If @delay is 0, queue @dwork->work immediately.  This is for
-- 
2.31.0.291.g576ba9dcdaf-goog


WARNING: multiple messages have this Message-ID (diff)
From: Sami Tolvanen <samitolvanen@google.com>
To: Kees Cook <keescook@chromium.org>
Cc: Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	 Masahiro Yamada <masahiroy@kernel.org>,
	Will Deacon <will@kernel.org>, Jessica Yu <jeyu@kernel.org>,
	 Arnd Bergmann <arnd@arndb.de>, Tejun Heo <tj@kernel.org>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	 Christoph Hellwig <hch@infradead.org>,
	Peter Zijlstra <peterz@infradead.org>,
	 Sedat Dilek <sedat.dilek@gmail.com>,
	bpf@vger.kernel.org,  linux-hardening@vger.kernel.org,
	linux-arch@vger.kernel.org,
	 linux-arm-kernel@lists.infradead.org,
	linux-kbuild@vger.kernel.org,  linux-pci@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	 clang-built-linux@googlegroups.com,
	Sami Tolvanen <samitolvanen@google.com>
Subject: [PATCH v4 06/17] kthread: use WARN_ON_FUNCTION_MISMATCH
Date: Wed, 31 Mar 2021 14:27:10 -0700	[thread overview]
Message-ID: <20210331212722.2746212-7-samitolvanen@google.com> (raw)
In-Reply-To: <20210331212722.2746212-1-samitolvanen@google.com>

With CONFIG_CFI_CLANG, a callback function passed to
__kthread_queue_delayed_work from a module points to a jump table
entry defined in the module instead of the one used in the core
kernel, which breaks function address equality in this check:

  WARN_ON_ONCE(timer->function != ktead_delayed_work_timer_fn);

Use WARN_ON_FUNCTION_MISMATCH() instead to disable the warning
when CFI and modules are both enabled.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
 kernel/kthread.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/kthread.c b/kernel/kthread.c
index 1578973c5740..a1972eba2917 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -963,7 +963,8 @@ static void __kthread_queue_delayed_work(struct kthread_worker *worker,
 	struct timer_list *timer = &dwork->timer;
 	struct kthread_work *work = &dwork->work;
 
-	WARN_ON_ONCE(timer->function != kthread_delayed_work_timer_fn);
+	WARN_ON_FUNCTION_MISMATCH(timer->function,
+				  kthread_delayed_work_timer_fn);
 
 	/*
 	 * If @delay is 0, queue @dwork->work immediately.  This is for
-- 
2.31.0.291.g576ba9dcdaf-goog


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2021-03-31 21:28 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-31 21:27 [PATCH v4 00/17] Add support for Clang CFI Sami Tolvanen
2021-03-31 21:27 ` Sami Tolvanen
2021-03-31 21:27 ` [PATCH v4 01/17] add " Sami Tolvanen
2021-03-31 21:27   ` Sami Tolvanen
2021-03-31 21:27 ` [PATCH v4 02/17] cfi: add __cficanonical Sami Tolvanen
2021-03-31 21:27   ` Sami Tolvanen
2021-03-31 21:27 ` [PATCH v4 03/17] mm: add generic function_nocfi macro Sami Tolvanen
2021-03-31 21:27   ` Sami Tolvanen
2021-03-31 21:27 ` [PATCH v4 04/17] module: ensure __cfi_check alignment Sami Tolvanen
2021-03-31 21:27   ` Sami Tolvanen
2021-04-01  1:31   ` kernel test robot
2021-04-01 16:24     ` Sami Tolvanen
2021-03-31 21:27 ` [PATCH v4 05/17] workqueue: use WARN_ON_FUNCTION_MISMATCH Sami Tolvanen
2021-03-31 21:27   ` Sami Tolvanen
2021-03-31 21:27 ` Sami Tolvanen [this message]
2021-03-31 21:27   ` [PATCH v4 06/17] kthread: " Sami Tolvanen
2021-03-31 21:27 ` [PATCH v4 07/17] kallsyms: strip ThinLTO hashes from static functions Sami Tolvanen
2021-03-31 21:27   ` Sami Tolvanen
2021-03-31 21:27 ` [PATCH v4 08/17] bpf: disable CFI in dispatcher functions Sami Tolvanen
2021-03-31 21:27   ` Sami Tolvanen
2021-03-31 21:27 ` [PATCH v4 09/17] treewide: Change list_sort to use const pointers Sami Tolvanen
2021-03-31 21:27   ` Sami Tolvanen
2021-03-31 21:27 ` [PATCH v4 10/17] lkdtm: use function_nocfi Sami Tolvanen
2021-03-31 21:27   ` Sami Tolvanen
2021-03-31 21:27 ` [PATCH v4 11/17] psci: use function_nocfi for cpu_resume Sami Tolvanen
2021-03-31 21:27   ` Sami Tolvanen
2021-03-31 21:27 ` [PATCH v4 12/17] arm64: implement function_nocfi Sami Tolvanen
2021-03-31 21:27   ` Sami Tolvanen
2021-03-31 21:27 ` [PATCH v4 13/17] arm64: use function_nocfi with __pa_symbol Sami Tolvanen
2021-03-31 21:27   ` Sami Tolvanen
2021-03-31 21:27 ` [PATCH v4 14/17] arm64: add __nocfi to functions that jump to a physical address Sami Tolvanen
2021-03-31 21:27   ` Sami Tolvanen
2021-03-31 21:27 ` [PATCH v4 15/17] arm64: add __nocfi to __apply_alternatives Sami Tolvanen
2021-03-31 21:27   ` Sami Tolvanen
2021-03-31 21:27 ` [PATCH v4 16/17] KVM: arm64: Disable CFI for nVHE Sami Tolvanen
2021-03-31 21:27   ` Sami Tolvanen
2021-03-31 21:27 ` [PATCH v4 17/17] arm64: allow CONFIG_CFI_CLANG to be selected Sami Tolvanen
2021-03-31 21:27   ` Sami Tolvanen
2021-03-31 21:46 ` [PATCH v4 00/17] Add support for Clang CFI Kees Cook
2021-03-31 21:46   ` Kees Cook

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