netdev - Re: [PATCH net-next] bpf, lpm: fix overflows in trie

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Message-Id: <20170208.144038.1724270145023687764.davem@davemloft.net>
Date:   Wed, 08 Feb 2017 14:40:38 -0500 (EST)
From:   David Miller <davem@...emloft.net>
To:     daniel@...earbox.net
Cc:     ast@...nel.org, daniel@...que.org, dh.herrmann@...il.com,
        netdev@...r.kernel.org
Subject: Re: [PATCH net-next] bpf, lpm: fix overflows in trie_alloc checks

From: Daniel Borkmann <daniel@...earbox.net>
Date: Wed,  8 Feb 2017 01:19:43 +0100

> Cap the maximum (total) value size and bail out if larger than KMALLOC_MAX_SIZE
> as otherwise it doesn't make any sense to proceed further, since we're
> guaranteed to fail to allocate elements anyway in lpm_trie_node_alloc();
> likleyhood of failure is still high for large values, though, similarly
> as with htab case in non-prealloc.
> 
> Next, make sure that cost vars are really u64 instead of size_t, so that we
> don't overflow on 32 bit and charge only tiny map.pages against memlock while
> allowing huge max_entries; cap also the max cost like we do with other map
> types.
> 
> Fixes: b95a5c4db09b ("bpf: add a longest prefix match trie map implementation")
> Signed-off-by: Daniel Borkmann <daniel@...earbox.net>
> Acked-by: Alexei Starovoitov <ast@...nel.org>

Applied, thanks Daniel.