linux-kernel - [PATCH] lkdtm/bugs: Check for the NULL pointer after calling kmalloc

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Message-Id: <20220114082119.1270966-1-jiasheng@iscas.ac.cn>
Date:   Fri, 14 Jan 2022 16:21:19 +0800
From:   Jiasheng Jiang <jiasheng@...as.ac.cn>
To:     keescook@...omium.org, arnd@...db.de, gregkh@...uxfoundation.org
Cc:     linux-kernel@...r.kernel.org, Jiasheng Jiang <jiasheng@...as.ac.cn>
Subject: [PATCH] lkdtm/bugs: Check for the NULL pointer after calling kmalloc

As the possible failure of the kmalloc(), the not_checked and checked
could be NULL pointer.
Therefore, it should be better to check it in order to avoid the
dereference of the NULL pointer.
And since it is just a test, it may directly return without error
number.

Fixes: ae2e1aad3e48 ("drivers/misc/lkdtm/bugs.c: add arithmetic overflow and array bounds checks")
Signed-off-by: Jiasheng Jiang <jiasheng@...as.ac.cn>
---
 drivers/misc/lkdtm/bugs.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
index f4cb94a9aa9c..12c474a38494 100644
--- a/drivers/misc/lkdtm/bugs.c
+++ b/drivers/misc/lkdtm/bugs.c
@@ -325,6 +325,8 @@ void lkdtm_ARRAY_BOUNDS(void)
 
 	not_checked = kmalloc(sizeof(*not_checked) * 2, GFP_KERNEL);
 	checked = kmalloc(sizeof(*checked) * 2, GFP_KERNEL);
+	if (!not_checked || !checked)
+		return;
 
 	pr_info("Array access within bounds ...\n");
 	/* For both, touch all bytes in the actual member size. */
-- 
2.25.1