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Subject: Re: net/tcp: null-ptr-deref in
 __inet_lookup_listener/inet_exact_dif_match
To: Eric Dumazet <eric.dumazet@gmail.com>,
        Andrey Konovalov <andreyknvl@google.com>
References: <CAAeHK+z9bqpWqONBBL1rztkY-+NdzY4jfCzNzfnm63psxbW-2g@mail.gmail.com>
 <1478107305.7065.382.camel@edumazet-glaptop3.roam.corp.google.com>
Cc: "David S. Miller" <davem@davemloft.net>,
        Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
        James Morris <jmorris@namei.org>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        Patrick McHardy <kaber@trash.net>, netdev <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Dmitry Vyukov <dvyukov@google.com>,
        Alexander Potapenko <glider@google.com>,
        Kostya Serebryany <kcc@google.com>, Eric Dumazet <edumazet@google.com>,
        syzkaller <syzkaller@googlegroups.com>
From: David Ahern <dsa@cumulusnetworks.com>
Message-ID: <f92b8a3e-9318-90c4-009a-15da3897ff6b@cumulusnetworks.com>
Date: Wed, 2 Nov 2016 12:31:20 -0600
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On 11/2/16 11:21 AM, Eric Dumazet wrote:
> Thanks for your report.
> 
> David, please take a look.
> 
> TCP MD5 can call __inet_lookup_listener() with a NULL skb.

interesting. I did not test md5 before sending, but doing so now I am not able to trigger the panic with any combination of passwords - correct, wrong, none, no listener, etc. perhaps I am missing a sysctl setting.

Will send a fix. I see the call to __inet_lookup_listener with null skb.

> 
> Bug added in commit a04a480d4392ea6efd117be2de564117b2a009c0