[PATCH] s390/keyboard: Allocate key_maps and func_table with ARRAY_SIZE()

[PATCH] s390/keyboard: Allocate key_maps and func_table with ARRAY_SIZE()

[Kees Cook]

From: Kees Cook <kees+treewide@kernel.org>

In preparation for converting the kmalloc family of allocators to the
type-aware kmalloc_obj family, we need to make sure that the returned
type from the allocation matches the type of the variable being
assigned. (The kmalloc family returns "void *", which can be implicitly
cast to any pointer type.)

These allocate as many pointers as ebc_key_maps and ebc_func_table hold,
but the sizes were taken from the whole arrays, which would make the
allocation types pointers to those arrays rather than the "u_short **"
and "char **" being assigned. Allocate ARRAY_SIZE-many entries instead.
The resulting allocation sizes are the same.

Build tested ARCH=s390 allmodconfig with GCC s390x-linux-gnu 16.1.0:
drivers/s390/char/keyboard.o

Assisted-by: LLM coccinelle
Signed-off-by: Kees Cook <kees+treewide@kernel.org>
---
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: <linux-s390@vger.kernel.org>
---
 drivers/s390/char/keyboard.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/s390/char/keyboard.c b/drivers/s390/char/keyboard.c
index ecd9ace2b3aa..63bcb52d6e87 100644
--- a/drivers/s390/char/keyboard.c
+++ b/drivers/s390/char/keyboard.c
@@ -81,7 +81,8 @@ kbd_alloc(void) {
 	kbd = kzalloc_obj(struct kbd_data);
 	if (!kbd)
 		goto out;
-	kbd->key_maps = kzalloc(sizeof(ebc_key_maps), GFP_KERNEL);
+	kbd->key_maps = kcalloc(ARRAY_SIZE(ebc_key_maps),
+				sizeof(*kbd->key_maps), GFP_KERNEL);
 	if (!kbd->key_maps)
 		goto out_kbd;
 	for (i = 0; i < ARRAY_SIZE(ebc_key_maps); i++) {
@@ -93,7 +94,8 @@ kbd_alloc(void) {
 				goto out_maps;
 		}
 	}
-	kbd->func_table = kzalloc(sizeof(ebc_func_table), GFP_KERNEL);
+	kbd->func_table = kcalloc(ARRAY_SIZE(ebc_func_table),
+				  sizeof(*kbd->func_table), GFP_KERNEL);
 	if (!kbd->func_table)
 		goto out_maps;
 	for (i = 0; i < ARRAY_SIZE(ebc_func_table); i++) {
-- 
2.34.1

Re: [PATCH] s390/keyboard: Allocate key_maps and func_table with ARRAY_SIZE()

[Heiko Carstens]

On Thu, Sep 17, 2026 at 02:12:40PM -0700, Kees Cook wrote:
> From: Kees Cook <kees+treewide@kernel.org>
> 
> In preparation for converting the kmalloc family of allocators to the
> type-aware kmalloc_obj family, we need to make sure that the returned
> type from the allocation matches the type of the variable being
> assigned. (The kmalloc family returns "void *", which can be implicitly
> cast to any pointer type.)
> 
> These allocate as many pointers as ebc_key_maps and ebc_func_table hold,
> but the sizes were taken from the whole arrays, which would make the
> allocation types pointers to those arrays rather than the "u_short **"
> and "char **" being assigned. Allocate ARRAY_SIZE-many entries instead.
> The resulting allocation sizes are the same.
> 
> Build tested ARCH=s390 allmodconfig with GCC s390x-linux-gnu 16.1.0:
> drivers/s390/char/keyboard.o
> 
> Assisted-by: LLM coccinelle
> Signed-off-by: Kees Cook <kees+treewide@kernel.org>
> ---
> Cc: Heiko Carstens <hca@linux.ibm.com>
> Cc: Vasily Gorbik <gor@linux.ibm.com>
> Cc: Alexander Gordeev <agordeev@linux.ibm.com>
> Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
> Cc: Sven Schnelle <svens@linux.ibm.com>
> Cc: <linux-s390@vger.kernel.org>
> ---
>  drivers/s390/char/keyboard.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)

Applied, thanks!