netdev - Re: [PATCH net] 6lowpan: Off by one handling ->nexthdr

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Message-Id: <18F5B032-F127-4EB9-8DB8-F760C6455431@holtmann.org>
Date:   Tue, 23 Apr 2019 19:10:28 +0200
From:   Marcel Holtmann <marcel@...tmann.org>
To:     Dan Carpenter <dan.carpenter@...cle.com>
Cc:     Alexander Aring <alex.aring@...il.com>,
        Jukka Rissanen <jukka.rissanen@...ux.intel.com>,
        "David S. Miller" <davem@...emloft.net>,
        linux-bluetooth@...r.kernel.org, linux-wpan@...r.kernel.org,
        netdev@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH net] 6lowpan: Off by one handling ->nexthdr

Hi Dan,

> NEXTHDR_MAX is 255.  What happens here is that we take a u8 value
> "hdr->nexthdr" from the network and then look it up in
> lowpan_nexthdr_nhcs[].  The problem is that if hdr->nexthdr is 0xff then
> we read one element beyond the end of the array so the array needs to
> be one element larger.
> 
> Fixes: 92aa7c65d295 ("6lowpan: add generic nhc layer interface")
> Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
> ---
> This is the only place which uses the NEXTHDR_MAX define, so I considered
> changing that to 256 instead.  Either fix would work.
> 
> net/6lowpan/nhc.c  | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)

patch has been applied to bluetooth-next tree.

Regards

Marcel