From: Jiasheng Jiang Date: Thu, 20 Jan 2022 09:29:36 +0000 (+0800) Subject: lkdtm/bugs: Check for the NULL pointer after calling kmalloc X-Git-Tag: v5.10.122~171 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=56ac04f35fc5dc8b5b67a1fa2f7204282aa887d5;p=users%2Fdwmw2%2Flinux.git lkdtm/bugs: Check for the NULL pointer after calling kmalloc [ Upstream commit 4a9800c81d2f34afb66b4b42e0330ae8298019a2 ] 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. Also, we need to kfree the 'not_checked' and 'checked' to avoid the memory leak if fails. 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 Acked-by: Dan Carpenter Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220120092936.1874264-1-jiasheng@iscas.ac.cn Signed-off-by: Sasha Levin --- diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c index a337f97b30e28..d39b8139b0961 100644 --- a/drivers/misc/lkdtm/bugs.c +++ b/drivers/misc/lkdtm/bugs.c @@ -231,6 +231,11 @@ 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) { + kfree(not_checked); + kfree(checked); + return; + } pr_info("Array access within bounds ...\n"); /* For both, touch all bytes in the actual member size. */