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Message-Id: <20180504.113920.1481897063505688262.davem@davemloft.net>
Date: Fri, 04 May 2018 11:39:20 -0400 (EDT)
From: David Miller <davem@...emloft.net>
To: daniel@...earbox.net
Cc: alexei.starovoitov@...il.com, netdev@...r.kernel.org,
bjorn.topel@...el.com
Subject: Re: [PATCH bpf-next] bpf, xskmap: fix crash in xsk_map_alloc error
path handling
From: Daniel Borkmann <daniel@...earbox.net>
Date: Fri, 4 May 2018 16:27:53 +0200
> If bpf_map_precharge_memlock() did not fail, then we set err to zero.
> However, any subsequent failure from either alloc_percpu() or the
> bpf_map_area_alloc() will return ERR_PTR(0) which in find_and_alloc_map()
> will cause NULL pointer deref.
>
> In devmap we have the convention that we return -EINVAL on page count
> overflow, so keep the same logic here and just set err to -ENOMEM
> after successful bpf_map_precharge_memlock().
>
> Fixes: fbfc504a24f5 ("bpf: introduce new bpf AF_XDP map type BPF_MAP_TYPE_XSKMAP")
> Signed-off-by: Daniel Borkmann <daniel@...earbox.net>
Acked-by: David S. Miller <davem@...emloft.net>
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