Hi,
On Sat, Sep 11, 2021 at 12:28:18PM +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.
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-ari...
Signed-off-by: Len Baker len.baker@gmx.com
drivers/net/ethernet/microsoft/mana/hw_channel.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/microsoft/mana/hw_channel.c b/drivers/net/ethernet/microsoft/mana/hw_channel.c index 1a923fd99990..0efdc6c3c32a 100644 --- a/drivers/net/ethernet/microsoft/mana/hw_channel.c +++ b/drivers/net/ethernet/microsoft/mana/hw_channel.c @@ -398,9 +398,7 @@ static int mana_hwc_alloc_dma_buf(struct hw_channel_context *hwc, u16 q_depth, int err; u16 i;
- dma_buf = kzalloc(sizeof(*dma_buf) +
q_depth * sizeof(struct hwc_work_request),GFP_KERNEL);
- dma_buf = kzalloc(struct_size(dma_buf, reqs, q_depth), GFP_KERNEL); if (!dma_buf) return -ENOMEM;
-- 2.25.1
I have received a email from the linux-media subsystem telling that this patch is not applicable. The email is the following:
Hello,
The following patch (submitted by you) has been updated in Patchwork:
* linux-media: net: mana: Prefer struct_size over open coded arithmetic - http://patchwork.linuxtv.org/project/linux-media/patch/20210911102818.3804-1... - for: Linux Media kernel patches was: New now: Not Applicable
This email is a notification only - you do not need to respond.
The question is: Why it is not applicable?. I have no received any bad comment and a "Reviewed-by:" tag from Haiyang Zhang. So, what is the reason for the "Not Applicable" state?.
Regards, Len