linux-kernel - Re: [PATCH] Remove hardcoded static string length

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Message-ID: <CAOWid-dYtkcKuNxoOyf3yqSJ7OtcNjaqJLVX1QhRUhYSOO6vHA@mail.gmail.com>
Date:   Wed, 24 May 2023 14:01:17 -0400
From:   Kenny Ho <y2kenny@...il.com>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     Marc Dionne <marc.dionne@...istor.com>,
        Kenny Ho <Kenny.Ho@....com>,
        David Howells <dhowells@...hat.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>, linux-afs@...ts.infradead.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Remove hardcoded static string length

On Wed, May 24, 2023 at 1:43 PM Andrew Lunn <andrew@...n.ch> wrote:
>
> The other end of the socket should not blow up, because that would be
> an obvious DOS or buffer overwrite attack vector. So you need to
> decide, do you want to expose such issues and see if anything does
> actually blow up, or do you want to do a bit more work and correctly
> terminate the string when capped?

Right... I guess it's not clear to me that existing implementations
null-terminate correctly when UTS_RELEASE causes the string to exceed
the 65 byte size of rxrpc_version_string.  We can of course do better,
but I hesitate to do strncpy because I am not familiar with this code
base enough to tell if this function is part of some hot path where
strncpy matters.

Regards,
Kenny