[PATCH] scsi: hpsa: Make buff allocation type unsigned

[PATCH] scsi: hpsa: Make buff allocation type unsigned

[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.)

The assigned type is "unsigned char **", but the converted allocation
type would be "char **", whose elements point to a character type of a
different signedness, so the two pointer types are not compatible. Take
the size from the assignment target instead. No change in allocation
size results.

Build tested ARCH=x86_64 allmodconfig with GCC 16.2.0:
drivers/scsi/hpsa.o

Assisted-by: LLM coccinelle
Signed-off-by: Kees Cook <kees+treewide@kernel.org>
---
Cc: Don Brace <don.brace@microchip.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: "Martin K. Petersen" <mkp@kernel.org>
Cc: <storagedev@microchip.com>
Cc: <linux-scsi@vger.kernel.org>
---
 drivers/scsi/hpsa.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index 8edad1830abe..364cff7671e5 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -6499,7 +6499,7 @@ static int hpsa_big_passthru_ioctl(struct ctlr_info *h,
 		return -EINVAL;
 	if (ioc->buf_size > ioc->malloc_size * SG_ENTRIES_IN_CMD)
 		return -EINVAL;
-	buff = kcalloc(SG_ENTRIES_IN_CMD, sizeof(char *), GFP_KERNEL);
+	buff = kcalloc(SG_ENTRIES_IN_CMD, sizeof(*buff), GFP_KERNEL);
 	if (!buff) {
 		status = -ENOMEM;
 		goto cleanup1;
-- 
2.34.1

Re: [PATCH] scsi: hpsa: Make buff allocation type unsigned

[Martin K. Petersen (Oracle)]

Kees,

> The assigned type is "unsigned char **", but the converted allocation
> type would be "char **", whose elements point to a character type of a
> different signedness, so the two pointer types are not compatible.
> Take the size from the assignment target instead. No change in
> allocation size results.

Applied to 7.4/scsi-staging, thanks!

-- 
Martin K. Petersen

Re: [PATCH] scsi: hpsa: Make buff allocation type unsigned

[Martin K. Petersen (Oracle)]

On Thu, 17 Sep 2026 14:11:38 -0700, Kees Cook wrote:

> 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.)
> 
> The assigned type is "unsigned char **", but the converted allocation
> type would be "char **", whose elements point to a character type of a
> different signedness, so the two pointer types are not compatible. Take
> the size from the assignment target instead. No change in allocation
> size results.
> 
> [...]

Applied to 7.4/scsi-queue, thanks!

[1/1] scsi: hpsa: Make buff allocation type unsigned
      https://git.kernel.org/mkp/scsi/c/d0105247ca7e

-- 
Martin K. Petersen