Re: [PATCH net] bpf: fix allocation warnings in bpf maps and integer overflow

[David Miller]

From: Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx>
Date: Sun, 29 Nov 2015 16:59:35 -0800

> From: Alexei Starovoitov <ast@xxxxxxxxxx>
> 
> For large map->value_size the user space can trigger memory allocation warnings like:
 ...
> To avoid never succeeding kmalloc with order >= MAX_ORDER check that
> elem->value_size and computed elem_size are within limits for both hash and
> array type maps.
> Also add __GFP_NOWARN to kmalloc(value_size | elem_size) to avoid OOM warnings.
> Note kmalloc(key_size) is highly unlikely to trigger OOM, since key_size <= 512,
> so keep those kmalloc-s as-is.
> 
> Large value_size can cause integer overflows in elem_size and map.pages
> formulas, so check for that as well.
> 
> Fixes: aaac3ba95e4c ("bpf: charge user for creation of BPF maps and programs")
> Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>

Applied and queued up for -stable, thanks.
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