Re: [PATCH] net: cdc_ncm: Deal with too low values of dwNtbOutMaxSize

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@xxxxxxxxxx>:

On Wed, 17 May 2023 13:38:08 +0000 you wrote:
> Currently in cdc_ncm_check_tx_max(), if dwNtbOutMaxSize is lower than
> the calculated "min" value, but greater than zero, the logic sets
> tx_max to dwNtbOutMaxSize. This is then used to allocate a new SKB in
> cdc_ncm_fill_tx_frame() where all the data is handled.
> 
> For small values of dwNtbOutMaxSize the memory allocated during
> alloc_skb(dwNtbOutMaxSize, GFP_ATOMIC) will have the same size, due to
> how size is aligned at alloc time:
> 	size = SKB_DATA_ALIGN(size);
>         size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
> Thus we hit the same bug that we tried to squash with
> commit 2be6d4d16a084 ("net: cdc_ncm: Allow for dwNtbOutMaxSize to be unset or zero")
> 
> [...]

Here is the summary with links:
  - net: cdc_ncm: Deal with too low values of dwNtbOutMaxSize
    https://git.kernel.org/netdev/net/c/7e01c7f7046e

You are awesome, thank you!
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