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Subject: Re: [PATCH] net: cxgb3_main: Add CAP_NET_ADMIN check to
 CHELSIO_GET_MEM
To:     Michael Ellerman <mpe@ellerman.id.au>, netdev@vger.kernel.org
Cc:     davem@davemloft.net, linux-kernel@vger.kernel.org,
        security@kernel.org, ivansprundel@ioactive.com, vishal@chelsio.com
References: <20200124094144.15831-1-mpe@ellerman.id.au>
From:   Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Message-ID: <7a7d18d3-8c8d-af05-9aa0-fa54fa0dc0b7@cogentembedded.com>
Date:   Sat, 25 Jan 2020 11:48:51 +0300
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Hello!

On 24.01.2020 12:41, Michael Ellerman wrote:

> The cxgb3 driver for "Chelsio T3-based gigabit and 10Gb Ethernet
> adapters" implements a custom ioctl as SIOCCHIOCTL/SIOCDEVPRIVATE in
> cxgb_extension_ioctl().
> 
> One of the subcommands of the ioctl is CHELSIO_GET_MEM, which appears
> to read memory directly out of the adapter and return it to userspace.
> It's not entirely clear what the contents of the adapter memory
> contains, but the assumption is that it shouldn't be accessible to all

    s/contains/is/? Else it sounds tautological. :-)

> users.
> 
> So add a CAP_NET_ADMIN check to the CHELSIO_GET_MEM case. Put it after
> the is_offload() check, which matches two of the other subcommands in
> the same function which also check for is_offload() and CAP_NET_ADMIN.
> 
> Found by Ilja by code inspection, not tested as I don't have the
> required hardware.
> 
> Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
[...]

MBR, Sergei