From cd677f83c4a2783c70d975752db7b02c438242a8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= <mic@digikod.net>
Date: Mon, 8 Apr 2024 09:46:20 +0200
Subject: [PATCH] kunit: Fix kthread reference
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[ Upstream commit f8aa1b98ce40184521ed95ec26cc115a255183b2 ]
There is a race condition when a kthread finishes after the deadline and
before the call to kthread_stop(), which may lead to use after free.
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Fixes: adf505457032 ("kunit: fix UAF when run kfence test case test_gfpzero")
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Rae Moar <rmoar@google.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Link: https://lore.kernel.org/r/20240408074625.65017-3-mic@digikod.net
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
lib/kunit/try-catch.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/lib/kunit/try-catch.c b/lib/kunit/try-catch.c
index f7825991d576a..d9d1df28cc52e 100644
--- a/lib/kunit/try-catch.c
+++ b/lib/kunit/try-catch.c
@@ -11,6 +11,7 @@
#include <linux/completion.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
+#include <linux/sched/task.h>
#include "try-catch-impl.h"
@@ -65,13 +66,14 @@ void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context)
try_catch->context = context;
try_catch->try_completion = &try_completion;
try_catch->try_result = 0;
- task_struct = kthread_run(kunit_generic_run_threadfn_adapter,
- try_catch,
- "kunit_try_catch_thread");
+ task_struct = kthread_create(kunit_generic_run_threadfn_adapter,
+ try_catch, "kunit_try_catch_thread");
if (IS_ERR(task_struct)) {
try_catch->catch(try_catch->context);
return;
}
+ get_task_struct(task_struct);
+ wake_up_process(task_struct);
time_remaining = wait_for_completion_timeout(&try_completion,
kunit_test_timeout());
@@ -81,6 +83,7 @@ void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context)
kthread_stop(task_struct);
}
+ put_task_struct(task_struct);
exit_code = try_catch->try_result;
if (!exit_code)
--
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