Commit 6943ee7c authored by Len Baker's avatar Len Baker Committed by Greg Kroah-Hartman
Browse files

usb: ohci: 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



Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarLen Baker <len.baker@gmx.com>
Link: https://lore.kernel.org/r/20210911112631.10004-1-len.baker@gmx.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9c172d4c

drivers/usb/host/ohci-hcd.c

+1 −2
Original line number Diff line number Diff line
@@ -191,8 +191,7 @@ static int ohci_urb_enqueue ( 
	}



	/* allocate the private part of the URB */

	urb_priv = kzalloc (sizeof (urb_priv_t) + size * sizeof (struct td *),

			mem_flags);

	urb_priv = kzalloc(struct_size(urb_priv, td, size), mem_flags);

	if (!urb_priv)

		return -ENOMEM;

	INIT_LIST_HEAD (&urb_priv->pending);