Commit 16e9bde2 authored by Len Baker's avatar Len Baker Committed by Ulf Hansson
Browse files

memstick: jmb38x_ms: Prefer struct_size over open coded arithmetic 

As noted in the "Deprecated Interfaces, Language Features, Attributes,
and Conventions" documentation [1], size calculations (especially
multiplication) should not be performed in memory allocator (or similar)
function arguments due to the risk of them overflowing. This could lead
to values wrapping around and a smaller allocation being made than the
caller was expecting. Using those allocations could lead to linear
overflows of heap memory and other misbehaviors.

So, use the struct_size() helper to do the arithmetic instead of the
argument "size + count * size" in the kzalloc() function.

[1] https://www.kernel.org/doc/html/v5.14/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments



Signed-off-by: default avatarLen Baker <len.baker@gmx.com>
Link: https://lore.kernel.org/r/20210911131933.2089-1-len.baker@gmx.com


Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent d47f163c

drivers/memstick/host/jmb38x_ms.c

+1 −2
Original line number Diff line number Diff line
@@ -927,8 +927,7 @@ static int jmb38x_ms_probe(struct pci_dev *pdev, 
		goto err_out_int;

	}



	jm = kzalloc(sizeof(struct jmb38x_ms)

		     + cnt * sizeof(struct memstick_host *), GFP_KERNEL);

	jm = kzalloc(struct_size(jm, hosts, cnt), GFP_KERNEL);

	if (!jm) {

		rc = -ENOMEM;

		goto err_out_int;