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: Len Baker <[email protected]>
---
drivers/i3c/master/mipi-i3c-hci/dma.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/i3c/master/mipi-i3c-hci/dma.c b/drivers/i3c/master/mipi-i3c-hci/dma.c
index af873a9be050..2990ac9eaade 100644
--- a/drivers/i3c/master/mipi-i3c-hci/dma.c
+++ b/drivers/i3c/master/mipi-i3c-hci/dma.c
@@ -223,7 +223,7 @@ static int hci_dma_init(struct i3c_hci *hci)
}
if (nr_rings > XFER_RINGS)
nr_rings = XFER_RINGS;
- rings = kzalloc(sizeof(*rings) + nr_rings * sizeof(*rh), GFP_KERNEL);
+ rings = kzalloc(struct_size(rings, headers, nr_rings), GFP_KERNEL);
if (!rings)
return -ENOMEM;
hci->io_data = rings;
--
2.25.1
On Sun, 5 Sep 2021, Len Baker wrote:
> 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: Len Baker <[email protected]>
Acked-by: Nicolas Pitre <[email protected]>
> ---
> drivers/i3c/master/mipi-i3c-hci/dma.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/i3c/master/mipi-i3c-hci/dma.c b/drivers/i3c/master/mipi-i3c-hci/dma.c
> index af873a9be050..2990ac9eaade 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/dma.c
> +++ b/drivers/i3c/master/mipi-i3c-hci/dma.c
> @@ -223,7 +223,7 @@ static int hci_dma_init(struct i3c_hci *hci)
> }
> if (nr_rings > XFER_RINGS)
> nr_rings = XFER_RINGS;
> - rings = kzalloc(sizeof(*rings) + nr_rings * sizeof(*rh), GFP_KERNEL);
> + rings = kzalloc(struct_size(rings, headers, nr_rings), GFP_KERNEL);
> if (!rings)
> return -ENOMEM;
> hci->io_data = rings;
> --
> 2.25.1
>
>
On Sun, 5 Sep 2021 16:40:54 +0200, Len Baker wrote:
> 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.
>
> [...]
Applied, thanks!
[1/1] i3c/master/mipi-i3c-hci: Prefer struct_size over open coded arithmetic
commit: 605fa23646dd9a86c4300e1719542a865111d1b6
Best regards,
--
Alexandre Belloni <[email protected]>